Hydrocarbon Cracking In A Regenerable Molten Media

Abstract

Hydrocarbon feedstocks are cracked at elevated temperatures in a regenerable molten media comprising a glassforming oxide, such as an oxide of boron, in combination with an alkali or alkaline earth metal oxide or hydroxide including mixtures thereof, to produce high yields of light olefins which olefins such as ethylene are useful in the synthesis of polymers and other valuable chemicals. The carbonaceous materials, such as coke, which are formed and suspended in the molten media during the cracking operation are gasified by contacting said carbonaceous materials with a gaseous stream containing oxygen, such as air, steam or carbon dioxide at temperatures of from about above the melting point of said medium to about 3,000.degree.F. in order to regenerate the melt. Preferably, the mole ratio of the alkkali alkali alkaline earth metal oxide and/or hydroxide, expressed as the oxide thereof, to the glass-forming oxide in the melt is maintained in the range of at least about 1 in order to significantly increase the gasification rate of the carbonaceous materials which are suspended in the molten media while at the same time suppressing the evolution of sulfur oxides from the gasification zone when the hydrocarbon feedstock contains sulfur and when a gaseous stream containing oxygen is employed as the gasifying reagent.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. Ser. No. 186,771, filed Oct. 5, 1971 and now abandoned.

Description

FIELD OF THE INVENTION

This invention relates to the preparation of unsaturated organic compounds such as ethylene from hydrocarbon feedstocks. More particularly, this invention relates to cracking a hydrocarbon feedstock at elevated temperatures in a regenerable molten media. Still more particularly, this invention relates to the cracking of a heavy hydrocarbon feedstock, e.g., hydrocarbons such as gas oils, crude oils, atmospheric or vacuum residua, in a regenerable molten media containing a glass-forming oxide such as an oxide of boron in combination with an alkali or alkaline earth metal oxide or hydroxide including mixtures thereof to produce cracked hydrocarbon products such as ethylene and carbonaceous materials. The carbonaceous materials such as coke which are formed during the cracking process are gasified by contacting said carbonaceous materials in the molten media with a gaseous stream containing an oxygen, i.e., air; water, i.e., steam; or carbon dioxide reagent at elevated temperatures in order to regenerate the melt. The cracked hydrocarbon products find use in the synthesis of polymers and other valuable chemicals.

DESCRIPTION OF THE PRIOR ART

The thermal cracking of hydrocarbons at elevated temperatures to produce olefinic compounds such as ethylene by employing a molten salt such as eutectic mixtures of lithium and potassium-chloride as the heat transfer medium is wellknown to the art. The cracking of hydrocarbon feedstocks in molten heat transfer media such as lead to produce ethylene has likewise been disclosed in the art.

However, the molten media which have heretofore been employed to crack hydrocarbons have suffered from one or more disadvantages which has resulted in limited industrial application of these processes. The difficulty primarily encountered in the prior art processes such as molten lead was the fact that the carbonaceous particles produced during the cracking operation were not suspended in the melt, but formed a separate phase which contaminated the liquid and gaseous products. Further, with molten media that partially suspended the coke, such as lithium-potassium chloride eutectics, the buildup of such carbonaceous material in or above the molten medium necessitated additional steps such as to physically remove the carbonaceous particles from the melt. In addition, numerous contacting media have been proposed in the literature including metals, alloys, slags, basalt and glass (see Czechoslovakian Patent No. 109,952) in order to effectuate the thermal cleavage of hydrocarbon feedstocks.

Recently it has been suggested that hydrocarbon feedstocks can be cracked in a molten salt of either alkali metal carbonate, alkali metal hydroxide, or a mixture thereof, to form hydrocarbon products containing ethylene and thereafter regenerating the molten salt by intimate contact with oxygen or steam (see U.S. Pat. Nos. 3,553,279 and 3,252,774). Such a molten medium, however, suffers from the disadvantage of undergoing decomposition at operating conditions normally employed for cracking hydrocarbon feedstocks, i.e., temperatures in range of from about 1,200.degree. to 1,650.degree.F. Accordingly, the art is in need of an alternate molten medium which, in addition to providing the heat transfer medium for the cracking of the hydrocarbon feedstock, will permit the rapid regeneration of the melt.

SUMMARY OF THE INVENTION

It has now been discovered that hydrocarbon feedstocks are converted to produce high yields of light olefins such as ethylene by a process which comprises contacting the hydrocarbon feedstock with a regenerable molten medium containing a glass-forming oxide, as hereinafter defined, in combination with an alkali or alkaline earth metal oxide or hydroxide, including mixtures thereof, at a temperature in the range of from about above the melting point of the medium to about 2,500.degree.F. for a time sufficient to form cracked hydrocarbon products and carbonaceous materials. Thereafter, the carbonaceous materials formed and suspended in the molten medium during the cracking operation are contacted with a gaseous stream containing as a reagent oxygen, e.g., air, steam or carbon dioxide including mixtures thereof, at a temperature in the range of from about the melting point of said medium to about 3,000.degree.F. for a period of time in order to regenerate the molten media. The regenerable molten media of the instant invention comprises a glass-forming oxide, by which is meant an oxide of boron, silicon, aluminum, titanium, vanadium, molybdenum, tungsten and mixtures thereof. It has been discovered that not all oxides of primary and secondary glass-forming compounds known in the art are amenable to the process of the instant invention. Specifically, oxides of such primary glass-forming elements as germanium, arsenic and antimony have been found unsuitable for the cracking or gasification processes described herein in that the oxides of these elements, i.e., glass-forming oxides of germanium, arsenic and antimony, are excessively reduced to their metal state in the presence of carbon at temperatures which would normally be employed to crack or gasify a hydrocarbon feedstock. Carbon in the form of coke will normally be present in the molten media to a greater or lesser degree in the practice of the process of the instant invention, as will be hereinafter described, in view of the fact that it is preferred to gasify only that amount of coke which is being formed in cracking zone in order to achieve a heat balanced system as well as to maintain a steady state coke concentration in the melt. In addition, a secondary glass-forming oxide, namely bismuth oxide, is likewise reduced in a molten media at elevated temperatures to its metal state in the presence of carbon.

Accordingly, the preferred glass-forming oxides which can be employed in the practice of the instant invention are selected from the group consisting of boron, silicon, vanadium, molybdenum, tungsten and mixtures thereof. The most preferred glass-forming oxide is an oxide of boron.

The glass-forming oxides are employed in combination with an alkali or alkaline earth metal oxide or hydroxide, including mixtures thereof, to comprise the molten media which is initially charged to the cracking zone. The preferred alkali metal oxides or hydroxides including sodium, potassium, lithium, cesium, and mixtures thereof. The preferred alkaline earth metals which are introduced into the cracking zone in either their corresponding oxide or hydroxide form include barium, strontium, calcium and magnesium. While the alkaline earth metal oxides or hydroxides may be employed alone in combination with a glass-forming oxide, it is preferred that when employing an alkaline earth metal oxide or hydroxide in the molten media system of this invention that alkali metal oxides or hydroxides be present in order to lower the melting point of the molten media to that temperature range which is preferred for conducting the cracking or gasification of a hydrocarbon feedstock.

The mole ratio of the alkali metal compound, that is the mole ratio of the alkali metal(s) and/or alkaline earth metal(s) oxide(s) and/or hydroxide(s) to the glass-forming oxide(s) is an important feature of the instant invention. It has been surprisingly discovered that when the mole ratio of the alkali and/or alkaline earth metal oxide(s) and/or hydroxide(s) expressed as the oxide(s) thereof to the glass-forming oxide is at least 1, and more preferably from about 1 to about 3, and still more preferably from about 1.2 to about 2.5, there occurs an unexpected increase in the gasification rate of the carbonaceous materials present in the molten media when the carbonaceous materials are contacted with a gasifying reagent such as air, in order to burn off the carbonaceous materials and thus regenerate the melt. In addition, by maintaining the mole ratio within this range, it has been discovered further that the sulfur emissions in the flue gas during gasification of the carbonaceous materials with a gaseous stream containing oxygen, i.e., air, are significantly reduced. Furthermore, maintaining the mole ratio below 3.0, and preferably below about 2.5, minimizes carbon dioxide emissions from the cracking zone.

As mentioned above, the mole ratio of the alkali metal compound is defined in terms of the oxide(s) of the alkali or alkaline earth metal(s) that is employed in combination with the glass-forming oxide. The basis for defining the mole ratio of the alkali metal compound in terms of its oxide form, i.e., "expressed as the oxide(s) thereof," is the fact that the alkali metal constituent of the alkali metal oxide(s), e.g., lithium oxide (Li.sub.2 O), alkaline earth metal oxide(s), e.g., barium oxide (BaO) and alkaline earth metal hydroxide, e.g., barium hydroxide (Ba(OH).sub.2) all possess a total number of equivalents of alkali metal or alkaline earth metal of two. The total number of equivalents of alkali metal in an alkali metal hydroxide, e.g., lithium hydroxide (LiOH), however, is one. Accordingly, it has been discovered that when an alkali metal hydroxide is employed as an alkali metal compound in combination with a glass-forming oxide to comprise the molten media of the instant invention, it is necessary to employ 2 moles of alkali metal hydroxide(s) for each mole of glass-forming oxide in order to achieve the same advantages exhibited by a molten media containing a glass-forming oxide in combination with 1 mole of either an alkali metal oxide, alkaline earth metal oxide or alkaline earth metal hydroxide. Therefore, it is evident that it is necessary to employ twice as many moles of an alkali metal hydroxide as compared to alkali metal oxide(s) or alkaline earth metal oxide(s) or hydroxide(s) in order to achieve the identical mole ratio of alkali metal compound to the glass-forming oxide. Hence, when the mole ratio of the alkali metal compound is expressed as the oxide of the particular alkali or alkaline earth metal employed, the singular effect is that the number of moles of alkali metal hydroxides that are employed in the molten media must be divided by two and then combined with the total number of moles of alkali metal oxides and alkaline earth metal oxides and hydroxides in order to determine the total number of moles of alkali metal compound expressed as oxide that are employed in a particular molten media. Thereafter, the total number of moles of the alkali metal compound is divided by the total number of moles of the glass-forming oxide(s) that is present in the molten media in order to determine the mole ratio of the alkali metal compound to the glass-forming oxide component in the melt.

Still further, it has been discovered that when an oxide of boron is employed as the glass-forming oxide, that the gasification rate as well as the suppression of sulfur emissions from the flue gas during air gasification is related not only to the mole ratio of the alkali or alkaline earth metal oxide or hydroxide to the oxide of boron but, in addition, to the mole ratio of the different alkali or alkaline earth metal oxides that are employed. Accordingly, it has been found that during the gasification of carbonaceous materials such as coke with an oxidizing gas such as air in a molten media containing boron oxide, that the gasification rate and the suppression of sulfur emissions is directly related to the basicity of the molten media in accordance with the following equation: ##SPC1##

The factor before each alkali or alkaline earth metal oxide has been experimentally determined and reflects the relative basicity of each component. When the hydroxide of an alkali or alkaline earth metal is employed in combination with an oxide of boron, the identical factors described in Equation I are multipled by the number of moles of alkali or alkaline earth metal hydroxides present in the melt, subject, however, to dividing the number of moles of alkali metal hydroxide by two, as described above, before multiplying by the factors indicated in Equation I. The basicity (R'), which is a modified mole ratio of the alkali and alkaline earth oxides to boron oxide and is equivalent to the mole ratio of those components times their appropriate weight factors as specified in Equation I above, should be maintained at a level of at least about 0.5, and preferably in the range of from about 0.5 to about 1.5, and more preferably from about 0.5 to about 1.0, to achieve the advantages mentioned above relating to increasing the gasification rate, suppressing the emissions of sulfur oxides from the gasification zone and minimizing carbon dioxide emissions from the cracking zone.

Further advantages of cracking a hydrocarbon feedstock in the above-mentioned molten medium reside in the ability of the molten media of this invention to: (a) suspend the carbonaceous materials formed in situ during the cracking operations uniformly throughout the melt, and (b) thereafter, upon contact with a gaseous stream containing oxygen or steam at elevated temperature, to promote the rapid gasification of said carbonaceous materials. Accordingly, the instant invention permits the thermal cracking of a heavy hydrocarbon feedstock such as atmospheric or vacuum residuum, the cracking of which feedstocks have heretofore not been feasible due to excessive coking in tubular reactors. In addition, in view of the fact that heavy hydrocarbon feedstocks, as hereinafter defined, such as residua and crude oils normally contain sulfur, e.g., thiols, thiophenes and sulfides, the molten media of the instant invention offers the additional advantages of significantly lowering the emission of pollutants into the the atmosphere by retaining the sulfur compounds produced during the burning of the carbonaceous materials with a gasifying reagent containing oxygen. Further, sulfur impurities initially present in the hydrocarbon feedstock are retained by the molten media of the instant invention in view of the fact that a major portion of the hydrogen sulfide formed during the cracking operation is retained by melt, particularly when the cracking step is conducted in the essential absence of steam. Also, a portion of the sulfur impurities that are present in the carbonaceous materials are believed to be leached out of the carbonaceous material by the molten media of the instant invention, thereby effectuating a further removal of sulfur from the carbonaceous materials. Furthermore, the molten media of the instant invention: (a) have a sufficiently low melting point and possess a suitably wide liquid range to permit a wide range of operating temperatures to be employed; (b) possess good thermal conductivity to allow efficient heat transfer; and (c) possess high stability such as to undergo essentially no decomposition to volatile products under high severity cracking and/or gasification conditions. Thus, it is evident that these advantageous properties exhibited by the stable molten media of the instant invention offer significant advantages in the thermal cracking of hydrocarbon feedstocks.

While not wishing to be bound to any particular theory, it is believed that the glass-forming oxides of the instant invention consist of network polymers or lineary chains. When a network-forming oxide (which network-forming oxide is referred to as a glass-forming oxide throughout the specification) is melted in combination with a network-modifying oxide (which network-modifying oxide is referred to as an alkali or alkaline earth metal oxide or hydroxide, including mixtures thereof), it is believed that the network structure of the glass is modified. This modification occurs as the metal oxide enters the glass structure and in so doing breaks some of the network connections (crosslinks). Addition of sufficient alkali metal oxide results in monomeric oxides, and upon further addition of alkali metal oxide results in the presence of unbound excess alkali metal oxide or hydroxide. In the molten state these network and/or linear chains are believed to be of sufficient length in order to effectuate the suspension of carbonaceous materials therein and, when contacted with a gasification reagent such as a gaseous stream containing oxygen, carbon dioxide or steam at elevated temperatures, to promote the rapid gasification of said carbonaceous materials.

Accordingly, the only requirement of the molten media of this invention is that said molten media contain a sufficient amount of the alkali or alkaline earth metal oxide(s) or hydroxide(s) in combination with the glass-forming oxides to be regenerable, that is both suspend the carbonaceous materials formed during the cracking reaction uniformly throughout the melt and thereafter promote the rapid gasification of said materials upon contact with a gaseous stream containing oxygen or steam or carbon dioxide at elevated temperatures. The use of the term glass-forming oxide is not meant to imply that all of the molten media described above can be rapidly cooled without crystallizing, that is upon cooling having the melt form a solid glass in the classical sense. While certain of the molten media of this invention can, in fact, form a solid glass upon cooling, others are well outside the classical solid glass-forming region. While the glass-forming oxides in combination with an alkali or alkaline earth metal oxide or hydroxide may be employed alone as the regenerable molten media, it is clear that the molten media of this invention may be employed in combination with other components such as metallic and nonmetallic oxides, sulfides, sulfates and various other salts in varying amounts so long as a sufficient amount of glass-forming oxide is employed in order that the molten media be regenerable. Typical examples of regenerable molten media containing alkali metal oxides, alkaline earth metal oxides and mixtures thereof in combination with glass-forming oxide that may be employed in the practice of the instant invention are shown in Table I, following:

TABLE I ______________________________________ Molten Glass Composition, Melting Mixture Mole Ratio Point.degree.F. ______________________________________ Na.sub.2 O.sup.. B.sub.2 O.sub.3 2/1 1157 Li.sub.2 O.sup.. K.sub.2 O.sup.. B.sub.2 O.sub.3 0.5/0.5/1 1070 Li.sub.2 O.sup.. Na.sub.2 O.sup.. B.sub.2 O.sub.3 0.5/0.5/1 1140 Li.sub.2 O.sup.. Cs.sub.2 O.sup.. B.sub.2 O.sub.3 0.3/0.7/1 1076 K.sub.2 O.sup.. V.sub.2 O.sub.5 0.6/1 734 Li.sub.2 O.sup.. Na.sub.2 O.sup.. WO.sub.3 1.1/1/2.1 917 K.sub.2 O.sup.. Li.sub.2 O.sup.. MoO.sub.3 0.4/1/1.4 955 Na.sub.2 O.sup.. SiO.sub.2.sup.. B.sub.2 O.sub.3 0.8/0.8/1 968 Li.sub.2 O.sup.. MgO.sup.. B.sub.2 O.sub.3 1.6/0.4/1 1450 Li.sub.2 O.sup.. BaO.sup.. B.sub.2 O.sub.3 1.6/0.4/1 1150 MgO.sup.. BaO.sup.. B.sub.2 O.sub.3 1.2/0.8/1 1600 ______________________________________

It is to be understood that although the molten medium of the instant invention is described in terms of the glass-forming and alkali or alkaline earth metal oxide or hydroxide components thereof, it is clearly within the scope of this invention to employ and define the molten media of this invention with respect to the compounds which are believed to be formed when a glass-forming oxide is heated to the molten state in combination with an alkali or alkaline earth metal oxide or hydroxide. For example, a molten media containing lithium oxide and potassium oxide as the alkali metal oxides and boron oxide as the glass-forming oxide in the following mole ratios, 0.53 Li.sub.2 O, 0.47 K.sub.2 O, 1.0 B.sub.2 O.sub.3, can also be expressed in the molten state as an alkali metal borate, specifically a lithium potassium metaborate on the basis of the following reaction:

0.53 mole Li.sub.2 O + 0.47 mole K.sub.2 O + 1 mole B.sub.2 O.sub.3 .fwdarw. 1.06 LiBO.sub.2 + .94 KBO.sub.2

hence, when a molar excess of the glass-forming oxide (B.sub.2 O.sub.3) is employed, the melt may comprise a glass-forming oxide in combination with an alkali metal borate in accordance with the following reaction:

0.53 Li.sub.2 O + 0.47 K.sub.2 O + 2 B.sub.2 O.sub.3 .fwdarw. 1.06 LiBO.sub.2 + 0.94 KBO.sub.2 + B.sub.2 O.sub.3

Accordingly, it is clearly with the purview of the instant invention to employ as the stable molten medium of this invention a glass-forming oxide, as defined above, in combination with an alkali metal compound wherein the alkali metal compound comprises either an alkali metal oxide or hydroxide, an alkaline earth metal oxide or hydroxide, or an alkali metal salt of the glass-forming oxide employed, e.g., alkali or alkaline earth metal borate. It is to be understood that any of the molten glass melts of this invention may be prepared by fusing any combination of raw materials, which upon heating will form a glass-forming oxide in combination with an alkali or alkaline earth metal oxide or hydroxide. Typically, the composition of a molten glass melt of the instant invention is achieved by mixing a glass-forming oxide with an alkali or alkaline earth metal hydroxide, carbonate or the like and thereafter heating the mixture to a molten state.

In the process of this invention, a wide variety of feedstocks may be converted to produce high yields of light olefins such as ethylene. Generally, cracking can be conducted in the above-described molten media with any hydrocarbon feedstock such as low boiling hydrocarbons, e.g., ethane, propane, butane, as well as high boiling hydrocarbons such as naphthas, gas oils and the like. Preferably the hydrocarbon feedstocks of this invention are heavy hydrocarbon feedstocks such as crude oils, heavy residua, atmospheric and vacuum residua, crude bottoms, pitch, asphalt, other heavy hydrocarbon pitch-forming residua, coal, coal tar or distillate, natural tars including mixtures thereof. Preferably, the hydrocarbon feedstock which is cracked in the stable molten media of the instant invention comprises a hydrocarbon feedstock which contains material boiling above about 400.degree.F at atmospheric pressure. The preferred hydrocarbon feedstocks which can be employed in the practice of the instant invention are crude oils, aromatic tars, and atmospheric or vacuum residua containing material boiling above about 650.degree.F at atmospheric pressure. Aromatic tar, atmospheric or vacuum residua are particularly preferred.

While not essential to the reaction, an inert diluent can be employed in order to regulate the hydrocarbon partial pressure in the molten media cracking zone. The inert diluent should normally be employed in a molar ratio of from about 1 to about 50 moles of diluent per mole of hydrocarbon feed, and more preferably 1 to 10. Illustrative of the diluents that may be employed are helium, carbon dioxide, nitrogen, steam, methane and the like.

This invention will be further understood by reference to the accompanying drawing which is a schematic flow diagram for thermally cracking a heavy hydrocarbon feedstock in the molten media of the instant invention.

A heavy hydrocarbon residua fraction having a boiling point at atmospheric pressure of above 650.degree.F and Conradson carbon content of 12 is passed by the way of line 1 into the cracking zone 2. Within the cracking zone 2 is maintained a molten bed containing lithium oxide and sodium oxide and an oxide of boron wherein the mole ratio of lithium oxide to sodium oxide is 70- 30 and the mole ratio of lithium and sodium oxide to boron oxide is 2, such that the basicity of the molten media is about 0.75. The liquid hydrocarbon feedstock passing by way of line 1 is introduced into the cracking zone 2 by bubbling the feedstock through the molten glass media 3. Alternatively, the molten media may be sprayed into the reactor or trickled down the reactor walls as the hydrocarbon feedstock passes through the reactor. The molten media may flow either concurrently or countercurrently to the flow of the hydrocarbon feedstock.

The temperature of the molten media 3 is maintained in the range of from about 1,200.degree. to about 2,000.degree.F., and more preferably from about 1,300.degree. to about 1,700.degree.F. in order to form cracked hydrocarbon products and carbonaceous materials. The temperature of the molten media is maintained within the abovementioned range due to the exothermic gasification reaction of the carbonaceous materials formed during the cracking reaction, as will be hereinafter described, such that the molten media provides the heat for the cracking operation. Depending upon the temperature and the specific type of hydrocarbon feedstock, the rate at which the feedstock is passed via line 1 into cracking zone 2 is in the range of from about 0.1 to about 100 w./w./hr. (weight of feed/weight of melt/hour), and more preferably from about 0.1 to about 20 w./w./hr. Pressures are not a critical feature of the instant invention such that the reaction may be conducted at a pressure ranging from subatmospheric, e.g., 0.1 atmosphere to about 50 atmospheres, preferably from about 1 to about 10 atmospheres. The reaction time, as expressed in the amount of time the feedstock is in contact with the melt 3, i.e., residence time, is in the range of from about 0.01 to about 20 seconds, and more preferably from about 0.3 to about 5.0 seconds.

After the hydrocarbon feedstock has been cracked in the molten glass media at the desired temperature and pressure, the gaseous effluent emanating from the molten media 3 passes overhead from the cracking zone 2 and is recovered by the way of line 4. The cracked products passing by way of line 4 are cooled by being subjected to a quenching medium introduced by way of line 5. Thereafter, the cracked products are further cooled to condense and separate liquid products from the gaseous products containing light olefins by passing the quenched products by the way of line 6 to a fractionation zone, not shown. Most of the hydrogen sulfide formed during the cracking operation is absorbed by the melt particularly when the cracking operation is conducted in absence of significant amounts of steam. The product distribution obtained by cracking a hydrocarbon feedstock in the manner described above is substantially identical to the product distribution obtained by subjecting the same feedstock, under identical conditions, to the well known steam cracking process.

The significant advantage of employing the molten glass media of the instant invention is that the carbonaceous materials which are formed during the above-described cracking process become uniformly suspended throughout the melt and can be gasified, i.e., burned to gaseous products, when contacted with a gasifying reagent such as an oxidizing gas, i.e., air steam or carbon dioxide at elevated temperatures in order to rapidly regenerate the molten glass media. Accordingly, the molten media containing suspended carbonaceous material is withdrawn from the cracking zone 2 by way of line 7 and is passed by way of line 7 into a gasification zone 8. The rate at which the molten media is withdrawn from the cracking zone depends on the type of hydrocarbon feedstock being pyrolyzed and the rate at which the feedstock is being introduced into the cracking zone 2. Preferably, a vapor lift is employed in order to circulate the molten media by way of line 7 from the cracking zone 2 to the gasification zone 8.

The carbonaceous materials which are formed during the thermal cracking reaction may be generally described as solid particle-like materials having a high carbon content such as those materials formed during high temperature pyrolysis of organic compounds and normally referred to as coke. While the carbonaceous material heretofore discussed has been produced in situ during the cracking of a hydrocarbon feedstock, as described above, it should be emphasized that it is clearly within the scope of the instant invention to gasify carbonaceous materials which may be added, in conjunction with or independently of a thermal cracking reaction, to the molten media of the instant invention in the form of coal of various grades, polygnite, lignite coal, coke of various types such as coal coke and petroleum coke, peat, graphite, charcoal and the like. Accordingly, the term gasification as used herein describes the contacting of such carbonaceous materials in the molten glass media of the instant invention with a gasifying reagent comprising a gaseous stream containing oxygen, steam, carbon dioxide and mixtures thereof. The gasification reaction is carried out by contacting the carbonaceous material in the molten media 9 with the gasifying reagent introduced into the gasification zone 8 by the way of line 10. The gasification reaction is carried out at temperatures in the range of from about the melting point of the molten media to 3,000.degree.F. or higher and at a pressure in the range of from subatmospheric to about 100 atmospheres. Preferably, the temperature at which the gasification reaction is carried out is in the range of from about 1,200.degree. to about 2,000.degree.F., and more preferably from about 1,400.degree. to about 1,800.degree.F. It is preferred to maintain the pressure in the gasification zone in the range of from 1 to about 10 atmospheres.

When a gaseous stream containing oxygen is employed as the gasifying reagent in order to regenerate the molten media, the amount of oxygen which must be present in the gaseous stream is in the range of from about 1 to about 100 weight % oxygen, and more preferably in the range of from about 10 to about 25 weight % oxygen. Normally, the gaseous stream containing oxygen is passed through the molten media 9 at a rate of less than about 0.01 w./w./hr. (weight of oxygen/weight of molten media/hour) to about 50 w./w./hr., and more preferably from about 0.01 w./w./hr. to about 10 w./w./hr. Most preferably, air is introduced by way of line 10 at a temperature in the range of from about 100.degree. to about 1,000.degree.F. in order to effect a rapid regeneration of the molten media.

Alternatively, a gaseous stream containing steam or carbon dioxide may also be introduced as the gasifying reagent by way of line 10 into the gasification zone 8 in order to regenerate the molten media. When steam is employed as the gasifying reagent, the amount of steam which must be present in the gaseous stream is in the range of from about 10 to 100 weight % and more preferably from about 50 to 100 weight %. The steam is normally introduced by way of line 10 at a temperature in the range of from about 300.degree. to about 1,000.degree.F., and at a pressure in the range from about 100 to about 500 psig in order to regenerate the molten media. In the event a gaseous stream containing carbon dioxide is employed as the gasifying reagent, the amount of carbon dioxide that must be present in the gaseous stream is in the range of from about 10 to about 100 weight %. Preferably, the temperature and pressure at which carbon dioxide is introduced into the gasification zone 8 is in the range of from about 100.degree. to 1,000.degree.F. and 100 to 1,000 psig, respectively.

The specific gasification rate of the carbonaceous materials in individual stable, regenerable molten media, as defined by the amount of carbonaceous material which is gasified per hour per cubic foot of melt, is dependent upon the temperature at which the gasification process is carried out, as well as the residence time of the oxygen containing gas or steam in the melt, the concentration of carbonaceous material in the melt, and feed rate of oxygen containing gas into the media. As a general rule, the carbon gasification rate increaes as the temperature of the melt, concentration of carbonaceous materials and feed rate of the oxygen containing gas increase. Preferably, the concentration of carbonaceous materials in the molten medium is maintained idn the range of from 0.1 to about 60 weight %, and more preferably from about 1.0 to about 20 weight %, in order to effect a rapid gasification thereof.

The gaseous products produced by contacting the carbonaceous materials in the molten glass media with either an oxidizing gas, steam or CO.sub.2 are recovered from the gasification zone by way of line 11. When steam is employed as the gasifying reagent, a hydrogen-rich gaseous effluent is produced and recovered by way of line 11. The contacting of the carbonaceous materials with steam under the preferred conditions of temperature and pressure for regenerating the molten media of the instant invention, normally 1,500.degree.F. and atmospheric pressure, respectively, result in a gaseous effluent containing about 75 mole % hydrogen and about 24 mole % carbon oxides. Based on thermodynamic considerations, however, the gasification of carbonaceous materials with steam in the molten media of the instant invention at lower temperatures, preferably below 1,000.degree.F., and at elevated pressures would result in formation of a methane-rich gaseous effluent.

As opposed to the production of either a hydrogen or methane-rich steam when steam is employed as the gasifying reagent, the use of an oxygen containing gas such as air as the gasifying reagent results in the formation of a nitrogen-rich gaseous effluent. As mentioned above, when air is employed as the gasifying reagent, it has surprisingly been discovered that the mole ratio of the alkali component to the glass-forming oxide significantly affects the amount of sulfur oxides that are present in the gaseous effluent recovered from the gasification zone. Accordingly, when the mole ratio of the alkali or alkaline earth component to the glass-forming oxide is at least one or when the basicity of the molten media is at least 0.5 when an oxide of boron is employed as the glass-forming oxide, as defined above, it has been discovered that the emissions of sulfur oxides, predominantly in the form of sulfur dioxide in the flue gas, i.e., gaseous effluent, from the gasification zone is drastically reduced to a level of at least below about 500 parts per million by volume and preferably below 200 ppm by volume.

Thus, it is evident that the practice of the process of the instant invention offers the further advantage of removing objectionable contaminants such as sulfur impurities which are inherently formed during the processing of heavy hydrocarbon feedstocks. During the gasification of the carbonaceous materials with an oxidizing gas such as air, it is believed that the sulfur impurities present in the carbonaceous material are oxidized to sulfur oxides and are absorbed by the molten media of the instant invention. In addition, the process of the instant invention further serves to remove other contaminants present in a heavy hydrocarbon feedstock such as ash forming impurities which includes trace metals such as vanadium, iron and nickel that are normally present to a greater or lesser degree depending on the specific type of hydrocarbon feedstock being cracked and/or gasified.

The melt which has been regenerated as described above in gasification zone 8 is with drawn by way of line 12 and reintroduced back into the cracking zone 2. Normally, the amount of carbonaceous material that is gasified in the gasification zone 8 is substantially equivalent to the amount of carbonaceous material being formed during the cracking operation in the cracking zone 2, such that an overall balance of carbonaceous material is maintained throughout the system. A further advantage of employing a gaseous stream containing oxygen as the gasifying reagent is the fact that the gasification, i.e., burning of carbonaceous materials with oxygen is an exothermic reaction. Thus, when an oxidizing gas such as air is employed to gasify the carbonaceous materials in gasification zone 8, a sufficient amount of heat is liberated in order to provide an overall heat balance for both the gasification and cracking processes. Accordingly, in addition to regenerating the melt, the gasification of the carbonaceous materials with an oxidizing gas maintains the temperature of the melt such that the melt being passed by way of line 12 into the cracking zone 2 provides the heat required for the thermal cracking of the hydrocarbon feedstock.

As can be appreciated, while the molten media of the instant invention effectuates the removal of sulfur and ash-forming impurities from the carbonaceous materials by retaining these impurities during the gasification of the carbonaceous materials with an oxygen containing gasifying reagent, the continual buildup of these impurities in the melt requires that a slip-stream be withdrawn from the integrated cracking and gasification processes described above in order to restore the level of these impurities present in the melt to an acceptable level. While the slip-stream may be withdrawn from either the cracking or gasification zone or from any of the transfer lines wherein the molten media is being passed to either the cracking or gasification zone, i.e., lines 7 and 12, respectively, it is preferred to withdraw a stream of the molten media from transfer line 7. The basis for this preference of removing a portion of the contaminated molten media from the cracking zone resides in the fact that the cracking zone contains a greater amount of carbonaceous material, which carbonaceous material effects the reduction of alkali or alkaline earth metal sulfur oxides to metal sulfides, thereby facilitating the subsequent removal of the sulfur from the molten media, as will be hereinafter described.

The sulfur impurities present in the carbonaceous material as mentioned above are retained by the molten media during gasification with an oxidizing gas stream as well as being leached from the coke by the melt at elevated temperatures. When steam is employed as the gasifying reagent, however, the sulfur impurities are not converted to sulfur oxides and are not absorbed by the melt but rather the sulfur in carbonaceous material is primarily converted to hydrogen sulfide and is recovered in the effluent from the gasification zone. Thus, when an oxidizing gas stream is employed as the gasifying reagent, the sulfur impurities are absorbed by the melt in the form of metal sulfites or sulfates. The presence of carbonaceous materials in the molten media serves to reduce the metal sulfites or sulfates, predominantly alkali or alkaline earth metal sulfites, to their sulfide form. The metal sulfides are thereafter contacted with carbon dioxide and water in order to recover the sulfur impurities as hydrogen sulfide. Accordingly, a slip-stream 13 is withdrawn from line 7 and is passed to a sulfur recovery zone 14, wherein carbon dioxide and steam is introduced by way of line 15 and passed through the melt 16 at a temperature in the range of from about 800.degree. to about 1,800.degree.F. Alternatively, the molten media containing the sulfur impurity as a metal sulfide is passed into a sulfur recovery zone and is contacted with water in order to dissolve the melt and recover precipitated metals and ash and thereafter carbon dioxide is bubbled through the solution in order to recover the sulfur impurity as a hydrogen sulfide rich stream. In either embodiment, it is essential that the sulfur impurities be present in the sulfide form before being contacted with water or steam and carbon dioxide. In the event that a sufficient amount of carbonaceous material is not present in the system described above, and specifically in the cracking zone 2 in order to reduce the metal sulfate and sulfite to their sulfide form, it may be necessary to employ a reducing zone prior to passing the molten media into the sulfur recovery zone 16. If a reducing zone is required, it is evident that the slip-stream may be withdrawn from any point in the system and thereafter passed to the reducing zone wherein such reducing agents as carbon, hydrogen, carbon monoxide, methane, ethane or the like may be employed in order to reduce the metal sulfite or sulfates to their sulfide form. If such a reducing zone is required, it is preferred to have a holding zone below the cracking zone wherein the addition of further amounts of carbon may or may not be necessary, depending on the specific type of hydrocarbon feedstock, to effectuate the reduction of substantially all of the metal sulfate or sulfites to their sulfide form.

The hydrogen sulfide rich stream is recovered from the sulfur recovery zone by the way of line 17 and may be ultimately passed to a Claus plant for sulfur recovery. The molten media with a reduced sulfur content is withdrawn from the sulfur recovery zone by way of line 18, wherein this molten media containing a reduced sulfur level is returned to the gasification zone by way of line 19.

It will, likewise, be necessary to treat the molten media in order to remove trace metals and ash which have accumulated in the melt. Accordingly, a stream of the melt with a reduced sulfur content is withdrawn by way of line 20 from line 18 and is passed to an ash recovery zone, not shown, wherein the ash is separated from the melt by dissolution in water.

While the initial charge of the molten media to the cracking zone may consist solely of an alkali or alkaline earth metal oxide or hydroxide in combination with a glass-forming oxide, as described above, it is to be understood that the cracking and gasification of a heavy hydrocarbon feedstock in such a molten media in accordance with the processing scheme disclosed above will necessarily result over a prolonged period of time in varying the overall composition of the melt. For example, during the gasification when an oxygen containing gas is employed to gasify the carbonaceous materials present in the melt, a portion of the carbon dioxide that is formed during combustion, i.e., the gasification reaction, is absorbed by the melt. A fraction of this portion of carbon dioxide that is absorbed by the melt forms a carbonate in the melt, and predominantly an alkali or alkaline earth metal carbonate depending upon the specific alkali or alkaline earth metal oxide or hydroxide that is employed as the alkali or alkaline earth metal component of the molten media of the instant invention. The extent of the absorption of carbon dioxide by the molten glass media and thus the amount of carbonate that is formed in the melt of the instant invention is a function of the mole ratio of the alkali metal component to the glass-forming component, the specific alkali metal component employed, as well as the temperature of the melt and the carbon dioxide partial pressure existing over the bed of the molten media. As mentioned above, after a prolonged period of conducting the gasification process in the molten media of the instant invention such as will occur in a commercial unit, an equilibrium carbonate concentration will exist in the melt. The equilibrium carbonate concentration in any glass-forming melt will generally increase as the mole ratio of alkali metal oxide or hydroxide to glass-forming oxide increases, as the molecular weight of the cation increases, i.e., a melt containing potassium will absorb more carbon dioxide than a melt containing sodium, and a melt containing sodium will absorb more carbon dioxide than a melt containing lithium. The carbonate concentration predominantly in the form of alkali or alkaline earth metal carbonates in molten media of the instant invention is preferably kept to a minimum and, depending on the factors indicated above, will comprise below about 30 weight % of the melt, preferably below about 20, and more preferably below about 15 weight % of the melt.

In addition, the continuous melt cracking and gasification process of this invention will result in the composition of the molten media being effected by the presence of alkali or alkaline earth metal sulfates, sulfites and sulfides, as mentioned above, as well as with ash components, including that amount of residual carbonaceous material that may be tolerated in the melt. Accordingly, after continuous operation the steady state composition of the molten media will normally contain, in addition to the alkali and alkaline earth metal carbonates referred to above, from about 10 to about 20 weight % sulfates, 0 to about 10 weight % metal sulfites, 0 to about 10 weight % metal sulfides, from 3 to about 5 weight % carbonaceous materials and from about 2 to about 10 weight % ash. As will be appreciated, the melt composition will vary from the gasification zone to the cracking zone as well as in the reducing and sulfur recovery zones. For example, while the metal sulfate may be present in the melt in the gasification zone in an amount in the range of from 10 to 20 weight %, the amount of metal sulfate in the cracking, reducing and sulfur recovery zones will normally vary from about 0 to about 10 weight %. Likewise, whereas the amount of metal sulfide in the cracking, reducing and sulfur recovery zones is in the range of from about 5 to about 20 weight %, the amount of metal sulfide in the melt in the gasification zone is normally in the range of from about 0 to about 10 weight %. Thus, after continuous practice of the cracking and gasification processes described herein, the amount of alkali and alkaline earth metal glass-forming compound, such as alkali and alkaline earth metal borates, that is present in the melt when an oxide of boron is employed as the glass-forming oxide will normally constitute from about 15 to about 85 weight %, preferably at least about 30 weight %, and more preferably about 50 weight % of the molten media.

It should be noted that the presence of such alkali and alkaline earth metal sulfides, sulfates, sulfites, carbonates as well as ash components in the molten media of the instant invention will effectively alter, to a slight degree, the mole ratio of the alkali or alkaline earth metal oxide or hydroxide component to the glass-forming oxide component, as well as the basicity of the melt from the initial mole ratio and/or basicity of the molten media that was initially charged to the cracking zone. For example, the existence of an equilibrium carbonate concentration in the molten media as well as the presence of metal sulfates and sulfides will effectively lower, to a slight degree, the initial mole ratio of the alkali metal component to the glass-forming component which was charged to the cracking zone. Accordingly, the critical mole ratios, as well as the basicity, disclosed and claimed herein defines that mole ratio of the alkali metal compound expressed as the oxide thereof to the glass-forming oxide and basicity that must be maintained in the molten media in the cracking and gasification zones in the presence of the above-mentioned carbonate compounds, sulfur compounds, and ash components in order to obtain the advantages of the instant invention. By this is meant that after continuous cracking and gasification operations wherein a buildup of contaminants such as sulfur and carbonate compounds, coke, ash and the like occurs in the melt, the mole ratio of alkali metal compound to glass-forming compound does not include that amount of alkali metal compound that is present in these contaminants. Accordingly, due to the buildup of these contaminants in the melt and the loss, to a slight degree, of a small amount of alkali metal compound and thus a slight reduction in the mole ratio of the alkali metal compound to the glass-forming compound, it may be necessary to add additional amounts of alkali metal compound to the melt in order to maintain a specifically desired mole ratio of the alkali metal compound to the glass-forming oxide in the melt.

This invention will be further understood by reference to the following examples.

In the following examples, namely Examples 1 through 8, the molten media described therein was not employed under glass-forming carbonate equilibrium conditions, as discussed above.

EXAMPLE 1

A heavy residua hydrocarbon feedstock containing materials boiling above 650.degree.F. was introduced by means of a pump at a rate of about 2 grams per minute through a 1/4 inch inlet tube into a reactor containing a molten medium consisting of boron oxide as the glass-forming oxide in combination with lithium oxide and potassium oxide as the alkali metal oxide component. The cracking zone was 2 inches in diameter and 12 inches in length, and was placed in a Lindberg furnace. The melt temperature was measured by a thermocouple inserted into a thermowell positioned in the center of the molten media connected to a portable pyrometer. The effluent gases were passed directly to a gas chromatography for analysis. The quantity of C.sub.5 + liquid products and carbonaceous material, namely coke, produced was also measured.

TABLE II ______________________________________ CRACKING HEAVY HYDROCARBON IN REGENERABLE MOLTEN MEDIUM ______________________________________ Melt 0.53 Li.sub.2 O--0.47 K.sub.2 O--1.0 B.sub.2 O.sub.3 Temperature, .degree.F 1350 Feed (grams) 85 Pressure Atm. Product Yield, Wt.% on Feed ______________________________________ Hydrogen 0.5 Methane 10.8 Ethylene 17.2 Ethane 5.2 Propane 1.3 Propylene 17.0 C.sub.3 - Conversion 52.0 Butanes 0.4 i-Butylene 2.7 n-Butylenes 4.0 Butadiene 4.5 Total C.sub.4 11.6 Total C.sub.5 + Liquid 37.6 Coke 5.1 Weight Balance 106.3 ______________________________________

As can be seen from the results as shown in Table II, the cracking of a heavy hydrocarbon residual feedstock in the lithium oxide, potassium oxide, boron oxide melt of the instant invention results in a high conversion to C.sub.3 .sup.- products.

As discussed above, the carbonaceous particles which are formed during this cracking reaction become suspended in the molten medium. The specific operating conditions employed and the results obtained in gasifying with air the carbonaceous materials which became suspended in the melt during the cracking operation described above are set forth in the following Table III.

TABLE III ______________________________________ COKE GASIFICATION ______________________________________ Melt 0.53 LiO.sub.2 --0.47 K.sub.2 O -- 1.0 B.sub.2 O.sub.3 Temperature, .degree.F 1500 1500 Air Flow Rate (1/min.) 0.5 -- Steam Rate (gram/min.) -- 0.25 Pressure Atm. Atm. Effluent Gas Composi- tion, Mole % ______________________________________ H.sub.2 0.0 74.6 N.sub.2 82.2 0.0 O.sub.2 15.8 0.0 CO 0.0 3.4 CH.sub.4 0.0 0.7 CO.sub.2 2.0 20.8 H.sub.2 S 0.0 0.5 Sulfur in Effluent (Nanograms/cc) 10 400 H.sub.2 O Conversion, % -- 7.7 O.sub.2 Conversion, % 36 -- % Coke Gasified 100 100 % Coke Carried Out of Reactor Nil Nil ______________________________________

As can be seen from the results as shown in Table III, the gasification of the carbonaceous material with steam results in a hydrogen-rich gaseous effluent, while the gasification of the carbonaceous material with air as the oxygen-containing gas stream results in a nitrogen-rich gaseous effluent. Furthermore, it can be seen that the carbonaceous materials were completely converted to their respective gaseous streams.

EXAMPLE 2

This example indicates the excellent carbon gasification rates that are obtainable in accordance with the instant invention when carbonaceous materials present in the molten melts of the instant invention are contacted with air as the oxygen-containing gas stream at 1,500.degree.F.

TABLE IV ______________________________________ COKE GASIFICATION WITH AIR IN VARIOUS MELTS ______________________________________ Temperature: 1500.degree. F; Pressure: Atmospheric; Air Flow Rate: 4 STP Liters/min.; 950 grams melt containing 5 weight % (50 grams) fluid coke. Carbon Oxygen Gasification Conver- Rate (lb./ Run Melt sion (%) ft..sup.3 /hr.) ______________________________________ A 0.53 Li.sub.2 O -- 0.47 K.sub.2 O -- B.sub.2 O.sub.3 60 1.8 B 1.4 Na.sub.2 O -- 0.05 TiO.sub.2 --V.sub.2 O.sub.5 58 1.6 C 0.7 Li.sub.2 O -- 0.3 K.sub.2 O -- MoO.sub.3 52 1.6 D 2Na.sub.2 O -- B.sub.2 O.sub.3 45 1.5 E 0.48 Li.sub.2 O -- 0.52 Na.sub.2 O -- B.sub.2 O.sub.3 33 1.1 F 0.52 Li.sub.2 O -- 0.48 Na.sub.2 O -- WO.sub.3 17 1.0 G 1.4 Li.sub.2 CO.sub.3 -- K.sub.2 CO.sub.3.sup.(1) 14 0.4 H 1.3 LiCl -- KCl.sup.(2) 32 0.2 ______________________________________ .sup.(1) Run conducted at 1250.degree.F to avoid excessive decomposition of the melt. .sup.(2) Run conducted at air flow rate of 1 STP liters/min. as LiCl -- KCl melt volatilizes.

As can be seen from the results as shown in Table IV, the molten media of the instant invention (Runs A through F) which contain a glass-forming oxide(s) in combination with an alkali metal oxide promote the rapid gasification of the carbonaceous materials present in said melts, which gasification permits facile regeneration of the melt after the melt has been employed as the cracking medium for a hydrocarbon feedstock, as described in Example I.

The molten medium employed in Run G could not be conducted at the temperatures employed in Run A through F in view of the fact that this particular molten medium, at such temperature, evolves carbon dixide. Likewise in the particular molten media employed in Run H could not be conducted at the air flow rate employed for Runs A through F in view of the fact that, at such air flow rates, there occurs a significant loss of the molten media from the reactor due to volatization of the melt.

EXAMPLE 3

This example shows that steam may also be employed in order to gasify carbonaceous materials present in the molten medium of this invention.

TABLE V ______________________________________ COKE GASIFICATION WITH STEAM IN VARIOUS MELTS ______________________________________ Temperature: 1700.degree.F; Steam Flow Rate: 0.5 grams/min.; 950 Grams of melt containing 5 weight % (50 grams) Fluid Coke; Atmospheric Pressure. Carbon Steam Gasification Conver- Rate (lb./ Run Melt sion (%) ft..sup.3 /hr.) ______________________________________ A 0.53 Li.sub.2 O -- 0.47 K.sub.2 O -- B.sub.2 O.sub.3 87 1.8 B 0.48 Li.sub.2 O -- 0.52 Na.sub.2 O -- B.sub.2 O.sub.3 69 1.3 C 0.7 Na.sub.2 O -- V.sub.2 O.sub.5 55 0.8 D 0.52 Li.sub.2 O -- 0.48 Na.sub.2 O -- WO.sub.3 41 1.7 E Na.sub.2 O -- 2B.sub.2 O.sub.3 27 0.5 F 1.4 Na.sub.2 O -- V.sub.2 O.sub.5 13 0.2 G 2Na.sub.2 O -- B.sub.2 O.sub.3 12 0.2 ______________________________________

Table V indicates that steam is effective as a gasification reagent; however, it is noted that in order to obtain a gasification rate equivalent to those obtained when air is employed as the gasification reagent (Run A), higher gasification temperatures are required. Accordingly, employing gasification temperatures higher than 1,700.degree.F would likewise increase the gasification rates exhibited by the molten media in Runs E through G.

EXAMPLE 5

This example indicates the significant effect of the mole ratio of the alkali metal oxide in the glass-forming oxide in the gasification of carbonaceous materials with steam and air respectively in the molten medium of the instant invention.

TABLE VI ______________________________________ EFFECT OF ALKALI OXIDE/BORON OXIDE MOLE RATIO ON STEAM GASIFICATION OF COKE ______________________________________ Temperature: 1700.degree.F; H.sub.2 O Feed Rate: 0.53 gram/min.; 5 weight % fluid coke in 950 gram melt; Atmospheric Pressure. - Mole Ratio of Steam Carbon Alkali Oxide to Conver- Gasification Boron Oxide sion Rate (lb./cu.) Melt (R) % ft./hr.) ______________________________________ Na.sub.2 O.sup.. 2B.sub.2 O.sub.3 0.5 27 0.51 Li.sub.2 O.sup.. Na.sub.2 O.sup.. 2B.sub.2 O.sub.3 1 69 1.33 2Na.sub.2 O.sup.. B.sub.2 O.sub.3 2 13 0.25 ______________________________________

TABLE VII ______________________________________ EFFECT OF MELT COMPOSITION ON AIR BURNING OF COKE ______________________________________ Temperature: 1400.degree.F; Air Flow Rate: 4 STP liters/min.; 480 grams 50:50 mole % Lithium: Potassium borate; 4 weight % Sarnia Fluid Coke; Atmospheric Pressure. Mole Ratio of Carbon Alkali Oxide to Gasification Boron Oxide Rate (R) Oxygen Conversion (%) (lb./ft.3/hr.) ______________________________________ 0.5 2.4 0.2 1 17 1.4 1.3 22 2.1 1.6 30 2.9 2 22 1.9 ______________________________________

As can be seen from the results shown in Tables VI and VII, when the mole ratio of alkali metal oxide to glass-forming oxide was varied over the range of from about 0.5 mole alkali metal oxide to about 2.0 moles of alkali metal oxide per mole of glass-forming oxide, the carbon gasification rate was highest when the alkali metal oxide to glass-forming oxide was equal to approximately 1 when the carbonaceous materials were gasified with steam and at about 1.6 when the carbonaceous materials were gasified with an oxygen-containing gas stream namely air.

EXAMPLE 5

This example shows the effect of increasing the cconcentration of the carbonaceous materials on the gasification of said materials with air in a molten medium of the instant invention.

TABLE VIII ______________________________________ EFFECT OF COKE CONCENTRATION ON AIR GASIFICATION OF FLUID COKE ______________________________________ Temperature: 1500.degree.F; 480 grams Li/K borate; Air Flow Rate: 8STP L/min.; R no = 1. % Oxygen Carbon Gasification Coke, Weight % Conversion Rate (lb./ft..sup.3 /hr.) ______________________________________ 2 8.3 1.03 4 21.5 2.63 10 30.5 3.78 ______________________________________

As can be seen from the results as shown in Table VIII, for a given air flow through the melt, the oxygen conversion and carbon gasification rate increases rapidly with the amount of carbonaceous materials, i.e., coke, present in the melt.

EXAMPLE 6

This example shows the result of increasing the temperature in the molten medium of the instant invention when carbonaceous materials are gasified therein with either air or steam.

TABLE IX ______________________________________ TEMPERATURE EFFECT ON STEAM GASIFICATION OF COKE ______________________________________ Melt: 950 grams Li/K Borate; R = 1 Coke: 50 grams fluid coke Reactor: 2" I.D. Hastelloy H.sub.2 O Feed Rate (grams/min.): 0.25 Pressure: Atmospheric Melt Temperature, Steam Carbon Gasification .degree.F Conversion % Rate (lb./ft..sup.3 /hr.) ______________________________________ 1600 24 0.23 1700 50 0.60 1800 61 0.79 ______________________________________

TABLE X ______________________________________ TEMPERATURE EFFECT ON AIR BURNING OF COKE ______________________________________ Melt: 480 grams Li/K borate; R = 1 Coke: 20 grams fluid coke Reactor: 2" I.D. Pressure: Atmospheric Melt Air Oxygen Temp. Flow Rate Conversion Carbon Gasificcation .degree.F STP 1./min. % Rate (lb./ft..sup.3 /hr.) ______________________________________ 1400 2 15.7 0.45 1500 2 55.8 1.28 1600 2 83.0 1.96 1700 2 93.6 2.36 1500 4 29.0 1.60 1600 4 50.5 2.75 1700 4 71.0 3.44 ______________________________________

As can be seen from the results as shown in Tables IX and X, an increase in temperature during the air or steam gasification of carbonaceous materials in the molten medium of the instant invention results in an increase in the rate of carbon gasification in the melt.

EXAMPLE 7

This example shows the effect of increasing the superficial velocity in the molten medium of the instant invention when carbonaceous materials are gasified therein with air.

TABLE XI ______________________________________ EFFECT OF SUPERFICIAL GAS VELOCITY ON AIR BURNING OF COKE ______________________________________ Melt: 480 grams Li/K borate; R = 1 Coke: 20 grams fluid coke Temperature: 1500.degree.F Reactor: 2" I.D. Hastelloy Pressure: Atmospheric Carbon Superficial Oxygen Gasification Gas Velocity Air Flow Rate Conversion Rate (ft./sec.) (STP 1./min.) % (lb./ft..sup.3 /hr.) ______________________________________ 0.21 2 55.8 1.28 0.43 4 29.0 1.60 0.64 6 25.1 2.25 0.86 8 21.5 2.63 1.28 12 14.7 2.82 1.50 14 14.6 3.28 ______________________________________

As can be seen from the results shown in Table XI, an increase in superficial gas velocity above the melt results in increasing the rate of carbon gasification in the melt.

EXAMPLE 8

This example shows the effect of space time, defined as expanded melt volume/air feed rate, on the gasification of carbonaceous materials with air in the melts of the instant invention.

TABLE XII ______________________________________ EFFECT OF SPACE-TIME ON AIR BURNING OF FLUID COKE ______________________________________ Melt: Li/K borate: R=1 Coke: 5 wt.% fluid coke Temperature: 1400.degree.F Air Feed Rate: 6 STP liters/min. Superficial Gas Velocity: 0.6 ft./sec. Melt Space Oxygen Carbon Gasifica- Melt Coke Depth Time Conv. tion Rate (g) (g) (in.) (sec.) (%) (lb./ft..sup.3 /hr.) ______________________________________ 475 25 4.5 3.2 17.3 2.1 950 50 9.0 6.4 40.7 2.4 1425 75 13.5 9.6 58.5 2.3 ______________________________________

As can be seen from the results as shown in Table XII, for a given air flow rate and given coke concentration, the oxygen conversion increases rapidly with increasing space time, whereas the carbon gasification rate is unaffected.

In the following examples, namely Examples 9 through 18, the molten media employed therein was treated with a gaseous stream containing carbon dioxide in the amount and in the manner indicated in each example such that the molten media was employed under glass-forming carbonate equilibrium conditions.

EXAMPLE 9

This example, wherein boron oxide was employed as the glass-forming oxide, indicates the effect of the mole ratio of teh alkali metal component to the glass-forming oxide (R number) as well as the basicity of the molten medium on the amount of sulfur that is emitted from the bed of molten media during the air gasification of carbonaceous materials present in the molten media.,

TABLE XIII __________________________________________________________________________ SULFUR EMISSIONS IN FLUE GAS DURING AIR BURNING OF COKE __________________________________________________________________________ Melt: 225 g; Temperature: 1500.degree.F.; Air Feed Rate: 2 STP 1/min.; Reactor: 1.6" ID Silicon Carbide; Coke: 4 wt. % Fluid Coke (4.5 wt. % sulfur) 10% CO.sub.2 /N.sub.2 for 1.5 hrs. at 2 1/min. Li.sub.2 /Na.sub.2 O + K.sub.2 O R Basicity SO.sub.2 Level in Oxygen Con- Carbon Gasification Rate Melt Mole Ratio Number R.sup.1 flue gas, v ppm version, % (lb./cu. ft./hr.) __________________________________________________________________________ Li/Na 72/28 1.6 0.60 160 26 1.8 Li/Na 80/20 2.0 0.68 140 43 3.1 Li/K 64/36 1.6 0.76 50 58 4.3 Li/K 72/28 2.0 0.80 25 87 5.8 __________________________________________________________________________

As can be seen from the results as shown in Table XIII, as the basicity and the mole ratio of the alkali metal component (R number) increased, the sulfur emissions in the flue gas during gasification with an oxygen-containing gas decreased.

EXAMPLE 10

This example, wherein boron oxide was employed as the glass-forming oxide, indicates the effect of the basicity and the R number of the melt on the foaming of the molten media during the cracking operation of hydrocarbon feedstocks.

TABLE XIV __________________________________________________________________________ EFFECT OF BORATE MELT BASICITY ON FOAMING __________________________________________________________________________ Melt: 1300 g; Reactor: 2" 446 stainless steel; Feed Rate: 2 g/min Temperature: 1300-1350.degree.F; Atm. Pressure * Melt pretreated with 10% CO.sub.2 /N.sub.2 Li.sub.2 O/Na.sub.2 O/K.sub.2 O R Basicity Feed Run Melt Mole Ratio Number R.sup.1 Type Length (min) Comments __________________________________________________________________________ Li/Na 60/40 2.5 1.05 Gas Oil 130 No foaming. Li/Na* do. do. 1.05 Gas Oil 100 No foaming. Li/Na do. do. 1.05 Resid 30 Some foaming; small amount of melt came out of re- actor. Li/Na do. 3.0 1.26 Resid 43 Some foaming. Li/Na/K* 43/31/36 2.5 1.60 Gas Oil 92 Small amount of melt foamed out of reactor. __________________________________________________________________________

As can be seen from the results as shown in Table XIV, both the basicity of the molten media and specific type of hydrocarbon feedstock being treated by the cracking process influence whether or not the melt foams out of the cracking zone.

EXAMPLE 11

In this example, vanadium was employed as the glass-forming oxide and the effect of varying the mole ratio of the alkali metal oxide in the molten vanadate melt upon the gasification rate of carbonaceous materials present in the melt was studied.

TABLE XV ______________________________________ EFFECT OF R NUMBER ON AIR BURNING OF COKE IN VANADATE MELTS ______________________________________ Melt: 480 g K/Vanadate; Temperature 1600.degree.F; Air Flow Rate: 4 STP 1/min; Melt Pretreated with 2 STP 1/min 10% CO.sub.2 /N.sub.2 for 2 hours Coke: 20 gm Fluid Coke. Initial Initial Carbon Oxygen Gasification Rate R Number Conversion, % (lb/cu ft/hr) ______________________________________ 0.5 100 4.9 1.0 100 9.0 1.5 100 6.8 2.0* 100 9.4 ______________________________________ *1700.degree.F.

As can be seen from the results as shown in the above Table XV, the gasification rates in vanadate melts were extremely high at all of the mole ratios (R number) of alkali oxide employed. While these melts are reduced by the presence of carbonaceous materials, and thus are unstable, small amounts of this melt system may be employed in conjunction with more stable molten media in order to accelerate the overall gasification rates in the more stable melt systems.

EXAMPLE 12

In this example, silicon and tungsten were employed as the glass-forming oxides and the effect of gasifying carbonaceous materials in these melt systems were studied.

TABLE XVI ______________________________________ AIR BURNING OF COKE IN A SILICATE MELT ______________________________________ Melt: 480 g Na/Zn Silicate with Na/Zn mole Ratio: 75/25; R number = 1.5; Temperature: 1800.degree.F; Coke: 20 g fluid coke; Air Flow Rate: 0.5 STP 1/min; Melt pretreated with 2 STP 1/min 10% CO.sub.2 /N.sub.2 for 2 hours. Oxygen Conversion, % Carbon Gasification Rate (lb/cu ft/hr) ______________________________________ 100 0.14 ______________________________________

TABLE XVII ______________________________________ AIR BURNING OF COKE IN TUNGSTATE MELTS ______________________________________ Melt: 480 g, Li/Na Tungstate, 50/50 Mole ratio Li.sub.2 O/Na.sub.2 O; Temperature: 1600.degree.F; Air Flow Rate: 4 STP 1/min; Coke: 20 g Fluid Coke; Melt Pretreated with 2 STP 1/min, 10% CO.sub.2 /N.sub.2 for 2 hours. Initial Oxygen R Number Conversion, % ______________________________________ 1.0 29 ______________________________________

As can be seen from the results as shown in Tables XVI and XVII, respectively, silicon and tungsten were effective in gasifying the carbonaceous materials present in these melt systems.

EXAMPLE 13

In this example, molybdenum was employed as the glass-forming oxide and the data obtained for gasifying carbonaceous materials with air in this system is shown in Table XVIII.

TABLE XVIII ______________________________________ AIR BURNING OF COKE IN MOLYBDATE MELTS ______________________________________ Melt: 480 g, Li/Na Molybdate; 50/50 Li/Na mole ratio; Temperature: 1600.degree.F; Air Flow Rate: 4 STP 1/min; Coke: 20 g Fluid Coke; Melt pretreated with 2 STP 1/min, 10% CO.sub.2 /N.sub.2 for 2 hours. Initial Oxygen Carbon Gasification R Number Conversion, % Rate (lb/cu ft/hr) ______________________________________ 0.5* 56 1.5 1.0 21 1.6 1.5 65 6.8 2.0 46 4.3 2.5 60 3.8 ______________________________________ *1700.degree.F

The results as shown in Table XVIII indicate that the gasification rates of carbonaceous material present in this melt system increase with an increase in the R number of the melt.

EXAMPLE 14

This example, wherein boron oxide is employed as the glass-forming oxide, indicates the effect of basicity and R number on the gasification rates when alkali oxides are employed in the alkali metal component of the melt.

TABLE XIX __________________________________________________________________________ EFFECT OF ALKALI METAL BORATE MELT BASICITY ON COKE BURNING __________________________________________________________________________ RATES Melt: 490 g; Air Feed Rate: 4 STP 1/min; Coke: 20g Fluid Coke; Melt Pretreated with 4 1/min 10% CO.sub.2 /N.sub.2 for 1.5 hrs; Temperature: 1500.degree.F. Oxygen* Coke Burn- Mole Ratio R Basicity Conver- ing*Rate Melt Li.sub.2 O/Na.sub.2 O + K.sub.2 O Number R.sup.1 sion, % (lb/cu ft/hr) __________________________________________________________________________ Li/Na 60/40 1.0 0.42 20 1.5 do. 64/36 1.2 0.45 27 2.2 do. 71/29 1.6 0.59 44 3.8 do. 75/25 1.8 0.62 51 3.9 do. 78/22 2.0 0.68 74 5.8 Li/K 53/47 1.0 0.55 48 3.7 do. 50/50 1.2 0.69 88 6.5 do. 65/35 1.6 0.76 89 7.1 do. 71/29 1.8 0.79 94 7.2 do. 77/23 2.0 0.80 96 7.6 __________________________________________________________________________ *Initial conversion and rate.

As can be seen from the results as shown in Table XIX, excellent gasification rates are obtained when the basicity of the melt is above about 0.50 and the R number is above about 1.

EXAMPLE 15

This example shows the effect of employing alkaline earth metal oxides alone, and in combination with alkali metal oxide in the air gasification of carbonaceous materials in a boron oxide glass-forming melt.

TABLE XX __________________________________________________________________________ EFFECT OF ALKALINE EARTH OXIDES ON AIR BURNING OF COKE __________________________________________________________________________ Temperature: 1600.degree.F; Air Feed Rate: 4 STP 1/min; Melt: 480g; Fluid Coke: 20 g (4 wt.%, 60-100 mesh) Melt Pretreated with 2 1/min 20% CO.sub.2 /N.sub.2 for 2 hours. Carbon Gasification Rate at 50% Oxide Mole R Basicity Initial Oxygen Oxygen Conversion at Carbon Consumed Melt Ratio Number R.sup.1 Conversion, % 50% Carbon Consumed, % (lb/cu ft/hr) __________________________________________________________________________ Li/Mg 80/20 2.0 0.54 21 40 3.2 Li/Ca do. do. 0.53 27 42 3.4 Li/Sr do. do. 0.56 34 43 3.5 Li/Ba do. do. 0.58 30 46 3.6 Li/Ba 80/20 1.0 0.27 5 39 2.4 do. do. 2.0 0.54 30 46 3.6 do. do. 2.5 0.67 46 55 4.3 Mg/Ba** 60/40 2.0 0.76 14 20 1.6 __________________________________________________________________________ ** Run at 1700.degree.F.

As can be seen from the results as shown in Table XX, alkaline earth metal oxides are not nearly as active in promoting gasification as are the alkali metal oxides when the alkali metal oxides are employed alone (Example 14) or in combination with an alkaline earth metal oxide.

EXAMPLE 16

This example shows the effect of varying the basicity and thus the R number in gasifying carbonaceous materials in a borate melt with steam.

TABLE XXI ______________________________________ EFFECT OF ALKALI OXIDE/BORON OXIDE MOLE RATIO ON STEAM GASIFICATION OF COKE ______________________________________ Temperature: 1600.degree.F; H.sub.2 O Feed Rate: 0.23 g/min; 5 wt.% Fluid Coke in 475 gm melt; 60:40 mole % Lithium: Sodium Borate; Melt Pretreated with 2 STP 1/min 10% CO.sub.2 in N.sub.2. Carbon Mole Ratio Gasification* Alkali Oxide to Basicity Steam* Rate Boron Oxide (R) (R.sup.1) Conversion % (lb/cu ft/hr) ______________________________________ 0.75 0.32 15 0.28 1.0 0.42 22 0.38 1.4 0.59 22 0.38 2.0 0.84 45 0.75 2.5 1.05 48 0.95 ______________________________________ * At 10% carbon converted.

As can be seen from the results as shown in Table XXI, increasing the basicity and R number of the melt increases the steam gasification rate.

EXAMPLE 17

This example indicates that coal can be effectively gasified with steam in the glass-forming melts of the instant invention.

TABLE XXII ______________________________________ STEAM GASIFICATION OF COAL IN BORATE MELTS* ______________________________________ Melt: 450 g Li/Na Borate; Li.sub.2 O/Na.sub.2 O Mole Ratio = 60/40; R number = 2; Basicity = 0.78; 10 wt% Illinois No. 6 coal (< 100 mesh); H.sub.2 O feed rate: 0.23 g/min Temperature, .degree.F. 1200.degree.F. 1400.degree.F. 1600.degree.F. ______________________________________ Steam Conversion, % 46 90 80 Carbon Gasification Rate 0.7 2.1 2.0 (lb/cu ft/hr) Product Yield, Mole % Hydrogen 52.2 56.0 54.5 Carbon Monoxide 12.2 32.0 43.5 Methane 0.7 0.3 0.2 Carbon Dioxide 34.5 12.0 2.0 ______________________________________ * Data at 10% coal converted.

As can be seen from the results as shown in Table XXII, lowering the temperature, while lowering the gasification rate, increases the methane yield. Based on thermodynamic considerations, increasing the pressure while lowering the temperature would be expected to markedly increase the yield of methane.

EXAMPLE 18

This example indicates the effect of melt composition, specifically the effect on the gasification rate of carbonaceous materials with an oxygen-containing gas in molten borate-carbonate equilibrium melts.

TABLE XXIII __________________________________________________________________________ EFFECT OF MELT COMPOSITION ON COKE BURNING __________________________________________________________________________ Temp: 1500.degree.F; Melt: 480g Air Flow Rate: 4 STP 1/min; Fluid Coke: 20 g Carbonate Oxygen Carbon Gasifica- Melt R Melt Ratio in melt Conversion tion Rate (lb/ (Li/Na) Number Li.sub.2 O/Na.sub.2 O Mole % % ft.sup.3 /hr) __________________________________________________________________________ Borate 1.0 60/40 2.8 20 1.4 do. 1.2 64/36 -- 27 1.9 do. 1.6 71/29 4.6 44 2.8 Borate 1.8 75/25 -- 51 3.7 do. 2.0 78/22 5.0 74 5.0 do. 3.5 75/25 42.5.sup.(1) 68 5.7 Carbon- ate -- 78/22 100 30 2.2 __________________________________________________________________________ .sup.(1) Excess carbonate present.

As can be seen from the results as shown in Table XXIII, the gasification rate increases with an increase in the R number and with an increase in the carbonate concentration of the melt. It should be noted, however, that the gasification rate with a pure carbonate (100 percent) melt results in a lower burning rate than is obtained in the borate melt at an R number of between 1.2 and 1.6. Referring to Example 14, it can be seen that a borate melt having a basicity of about 0.5 under identical conditions also results in a higher gasification rate than the pure carbonate melt.

EXAMPLE 19

This example indicates that the sulfur impurities in the melt in the form of sulfides, specifically alkali or alkaline earth metal sulfides, can be effectively removed by contacting the metal sulfides with carbon dioxide and steam in molten media of the instant invention.

TABLE XXIV ______________________________________ REMOVING SULFUR FROM GLASS-FORMING MELTS WITH CO.sub.2 AND WATER ______________________________________ Reactor: Vycor Glass Melt: 225 grams of lithium, potassium borate, 50:50 ratio of lithium to potassium; 30 grams of Na.sub.2 S R Number = 1 Basicity = 0.58 Temperature: 1400.degree.F. H.sub.2 O Feed Rate: 0.75 grams/min Rate of H.sub.2 S Formation, CO.sub.2 Feed Rate 35 Min. on Stream, mmoles/min. mmoles/min ______________________________________ 2.9 6.57 5.9 5.25 8.7 6.15 ______________________________________

Claims

What is claimed is:

1. A process for cracking a hydrocarbon feedstock which comprises contacting said feedstock with a regenerable molten media comprising a glass-forming oxide selected from the group consisting of oxides of boron, vanadium silicon, tungsten, molybdenum and mixtures thereof in combination with an alkali metal compound selected from the group consisting of alkali metal oxides, alkali metal hydroxides, alkaline earth metal oxides, alkaline earth metal hydroxides and mixtures thereof wherein the mole ratio of the alkali metal compound expressed as the oxide thereof to the glass-forming oxide is at least about 1, at a temperature from above the melting point of said media to about 2,500.degree.F. for a time sufficient to form cracked hydrocarbon products.

2. The process of claim 1 wherein the temperature of the molten media is maintained in the range of from about 1,200.degree. to about 2,000.degree.F.

3. The process of claim 2 wherein said molten media contains a carbonate selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates and mixtures thereof.

4. The process of claim 2 wherein the glass-forming oxide is an oxide of boron.

5. The process of claim 2 wherein said molten media contains carbonaceous materials and is regenerated by contacting said molten media with a reagent selected from the group consisting of oxygen, steam, carbon dioxide and mixtures thereof at a temperature in the range of from about the melting point of said molten media to about 3,000.degree.F.

6. The process of claim 2 wherein the hydrocarbon feedstock contains sulfur.

7. The process of claim 6 wherein the amount of sulfur present in the molten media is reduced by:

a. contacting the sulfur compounds in the molten media with a reducing agent; and

b. thereafter contacting the reduced sulfur compounds formed in step (a) with carbon dioxide and water to form hydrogen sulfide as a recoverable product.

8. The process of claim 2 wherein the molten media contains an alkali metal borate and wherein the basicity of the molten media is in the range of from about 0.5 to about 2.0.

9. The process of claim 2 wherein the hydrocarbon feedstock is a heavy hydrocarbon feedstock containing sulfur.

10. A process for cracking a hyrocarbon feedstock which comprises contacting said hydrocarbon feedstock with a regenerable molten media comprising a glass-forming oxide selected from the group consisting of oxides of boron, vanadium, silicon, tungsten, molybdenum and mixtures thereof in combination with an alkali metal compound selected from the group consisting of alkali metal oxides, alkali metal hydroxides, alkaline earth metal oxides, alkaline earth metal hydroxides and mixtures wherein the mole ratio of the alkali metal compound expressed as the oxide thereof to glass-forming oxide is at least about 1, at a temperature in the range of from about the melting point of said media to about 2,500.degree.F. to form cracked hydrocarbon products and carbonaceous materials, and thereafter gasifying said carbonaceous materials formed during said cracking process by contacting said molten media containing the carbonaceous materials with a reagent selected from the group consisting of oxygen, carbon dioxide, steam and mixtures thereof at a temperature in the range of from about above the melting point of said medium to about 3,000.degree.F.

11. The process of claim 10 wherein the temperature of the molten media is maintained in the range of from about 1,200.degree. to about 2,000.degree.F.

12. The process of claim 11 wherein said molten media contains a carbonate selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates and mixtures thereof.

13. The process of claim 12 wherein the glass-forming oxide is an oxide of boron.

14. The process of claim 13, wherein the basicity of the molten media is at least about 0.5.

15. The process of claim 14 wherein said gasifying reagent is oxygen.

16. The process of claim 15 wherein the molten media contains an alkali metal borate and wherein the basicity of the molten media is in the range of from about 0.5 to about 2.0.

17. The process of claim 16 wherein the hydrocarbon feedstock is a heavy hydrocarbon feedstock containing sulfur.

18. The process of claim 17 wherein the amount of sulfur present in the molten media is reduced by:

a. contacting the sulfur compounds in the molten media with a reducing agent; and

b. thereafter contacting the reduced sulfur compounds formed in step (a) with carbon dioxide and water to form hydrogen sulfide as a recoverable product.

19. The process of claim 18 wherein said reducing agent is carbon.

20. The process of claim 19 wherein the reduced sulfur compounds formed in step (a) are selected from the group consisting of alkali metal sulfides, alkaline earth metal sulfides and mixtures thereof.

21. A process for gasifying carbonaceous materials which comprises contacting said carbonaceous materials in a regenerable molten media comprising a glass-forming oxide selected from the group consisting of oxides of boron, vanadium, silicon, tungsten, molybdenum and mixtures thereof in combination with an alkali metal compound selected from the group consisting of alkali metal oxides, alkali metal hydroxides, alkaline earth metal oxides, alkaline earth metal hydroxides and mixtures thereof wherein the mole ratio of the alkaline metal compound expressed as the oxide thereof to the glass-forming oxide is at least about 1 at a temperature in the range of from about the melting point of said molten media to about 3,000.degree.F. with a reagent selected from the group consisting of oxygen, carbon dioxide, steam and mixtures thereof.

22. The process of claim 21 wherein the temperature of the molten media is maintained in the range of from about 1,200.degree. to about 2,000.degree.F.

23. The process of claim 22 wherein the carbonaceous material is selected from the group consisting of coal, coke and mixtures thereof.

24. The process of claim 23 wherein the glass-forming oxide is an oxide of boron.

25. The process of claim 24 wherein the basicity of the molten media is at least about 0.5.

26. The process of claim 25 wherein the molten media contains a carbonate selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates, and mixtures thereof.

27. The process of claim 26 wherein the molten media contains an alkali metal borate and wherein the basicity of the molten media is in the range of from about 0.5 to about 2.0.

28. The process of claim 27 wherein the gasifying reagent is oxygen.

29. The process of claim 26 wherein the gaseous stream containing oxygen is air.

30. The process of claim 29 wherein the alkali metal compound is selected from the group consisting of alkali metal oxides, alkali metal hydroxides and mixtures thereof.

31. The process of claim 2 wherein the mole ratio of the alkali metal compound expressed as the oxide thereof to the glass-forming oxide is in the range of from about 1.2 to about 2.5.

32. The process of claim 7 wherein the reduced sulfur compounds are contacted with carbon dioxide and water at a temperature in the range of from about 800.degree. to about 1,800.degree.F.

33. The process of claim 32 wherein the mole ratio of the alkali metal compound expressed as the oxide thereof to the glass-forming oxide is in the range of about 1.2 to about 2.5.

34. The process of claim 33 wherein the hydrocarbon feedstock is a heavy hydrocarbon feedstock containing sulfur.

35. The process of claim 12 wherein the mole ratio of an alkali metal compound expressed as the oxide thereof to the glass-forming oxide is in the range of from about 1.2 to about 2.5.

36. The process of claim 35 wherein the gasifying reagent is oxygen.

37. The process of claim 36 wherein the hydrocarbon feedstock is a heavy hydrocarbon feedstock containing sulfur.

38. The process of claim 37 wherein the amount of sulfur present in the molten media is reduced by:

a. contacting the sulfur compound in the molten media with a reducing agent; and

b. thereafter contacting the reduced sulfur compound formed in step (a) with carbon dioxide and water to form hydrogen sulfide as a recoverable product.

39. The process of claim 38 wherein the reduced sulfur compounds are contacted with carbon dioxide and water at a temperature in the range of from about 800.degree. to about 1,800.degree.F.

40. The process of claim 39 wherein said reducing agent is carbon.

41. The process of claim 23 wherein the mole ratio of the alkali metal compound expressed as the oxide thereof to the glass-forming oxide is in the range of from about 1.2 to about 2.5.

42. The process of claim 41 wherein the gasifying reagent is oxygen.

43. A process for cracking a hydrogen feedstock which comprisess contacting said feedstock with a regenerable molten media comprising an oxide of boron in combination with an alkali metal compound selected from the group consisting of alkali metal oxides, alkali metal hydroxides, alkaline earth metal oxides, alkaline earth metal hydroxides and mixtures thereof at a temperature from above the melting point of said media to about 2,500.degree.F. for a time sufficient to form hydrocarbon products.

44. The process of claim 43 wherein the temperature of the molten media is maintained in the range of from about 1,200 to about 2,000.degree.F.

45. The process of claim 44 wherein the basicity of the molten media is maintained in the range of from about 0.5 to about 1.5.

46. The process of claim 45 wherein the hyrocarbon feedstock contains material boiling above about 400.degree.F. at atmospheric pressure.

47. The process of claim 46 wherein the hydrocarbon feedstock contains sulfur.

48. The process of claim 47 wherein the amount of sulfur present in the molten media is reduced by:

a. contacting the sulfur compounds in the molten media with a reducing agent; and

b. thereafter contacting the reduced sulfur compounds formed in step (a) with carbon dioxide and water at a temperature in the range of from about 800.degree. to about 1,800.degree.F. to form hydrogen sulfide as a recoverable product.

49. The process of claim 48 wherein the hyrocarbon feedstock is a heavy hydrocarbon residua fraction containing materials boiling above about the 650.degree.F. at atmospheric pressure.

50. The process of claim 49 wherein the alkali metal compound is selected from the group consisting of alkali metal oxides, alkali metal hydroxides and mixtures thereof.

51. The process of claim 50 wherein the molten media contains an alkali metal borate and wherein the basicity of the molten media is in the range of from about 0.5 to about 1.0.

52. A process for cracking a hydrocarbon feedstock which comprises contacting said hydrocarbon feedstock with a regenerable molten media comprising an oxide of boron in combination with an alkali metal compound selected from the group consisting of alkali metal oxides, alkali metal hydroxides, alkaline earth metal oxides, alkaline earth metal hydroxides and mixtures thereof at a temperature in the range of from about the melting point of said media to about 2,500.degree.F. to form cracked hydrocarbon products and carbonaceous materials, and thereafter gasifying a portion of said carbonaceous materials formed during said cracking process by contacting said molten media containing the carbonaceous materials with a reagent selected from the group consisting of oxygen, carbon dioxide, steam and mixtures thereof at a temperature in the range of from above about the melting point of said media to about 3,000.degree.F.

53. The process of claim 52 wherein said molten media contains a carbonate selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates and mixtures thereof.

54. The process of claim 53 wherein the basicity of the molten media is in the range of from about 0.5 to about 1.5.

55. The process of claim 54 said gasifying reagent is oxygen.

56. The process of claim 55 wherein the hydrocarbon feedstock is a heavy hydrocarbon feedstock containing sulfur.

57. The process of claim 56 wherein the amount of sulfur present in the molten media is reduced by:

a. contacting the sulfur compounds in the molten media with a reducing agent; and

b. thereafter contacting the reduced sulfur compounds formed in step (a) with carbon dioxide and water at a temperature in the range of from about 800.degree. to about 1,800.degree.F. to form hydrogen sulfide as a recoverable product.

58. The process of claim 57 wherein said reducing agent is carbon.

59. The process of claim 58 wherein the reduced sulfur compounds formed in step (a) are selected from the group consisting of alkali metal sulfides, alkaline earth metal sulfides and mixtures thereof.

60. The process of claim 59 wherein the cracking reaction is carried out at a temperature in the range of from about 1,300.degree.F. to about 1,700.degree.F. and wherein the gasification reaction is carried out at a temperature in the range from about 1,400.degree.F. to about 1,800.degree.F.

61. The process of claim 60 wherein the feedstock is a heavy hydrocarbon feedstock containing materials boiling above about 650.degree.F. at atmospheric pressure.

62. The process of claim 61 wherein the alkali metal compound is selected from the group consisting of alkali metal oxides, alkali metal hydroxides and mixtures thereof.

63. The process of claim 62 wherein the basicity of the molten media is maintained in the range of from about 0.5 to about 1.0.

64. The process of claim 63 wherein the alkali metal compound is selected from the group consisting of sodium oxide, lithium oxide, sodium hydroxide, lithium hydroxide, and mixtures

65. A process for gasifying carbonaceous materials which comprises contacting said carbonaceous materials in a regenerable molten media comprising an oxide of boron in combination with an alkali metal compound selected from the group consisting of alkali metal oxides, alkali metal hyroxides, alkaline earth metal oxides, alkaline earth metal hydroxides and mixtures thereof with a reagent selected from the group consisting of oxygen, carbon dioxide, steam and mixtures thereof at a temperature in the range of from about the melting point of said molten media to about 3,000.degree.F.

66. The process of claim 65 wherein the basicity of the molten media is in the range of from about 0.5 to about 1.5.

67. The process of claim 66 wherein the gasifying reagent is oxygen.

68. The process of claim 67 wherein the carbonaceous material is selected from the group consisting of coal, coke, and mixtures thereof.

69. The process of claim 68 wherein the alkali metal compound is selected from the group consisting of alkali metal oxides, alkali metal hydroxides and mixtures thereof.

70. The process of claim 69 wherein the carbonaceous materials contain sulfur.

71. The process of claim 70 wherein the amount of sulfur present in the molten media is reduced by:

a. contacting the sulfur compounds in the molten media with a reducing agent; and

b. thereafter contacting the reduced sulfur compounds formed in step (a) with carbon dioxide and water at a temperature in the range of from about 800.degree.F. to form hydrogen sulfide as a recoverable product.