U.S. patent application number 14/350758 was filed with the patent office on 2014-12-04 for process for dry cooling of coke with steam with subsequent use of the synthesis gas produced.
This patent application is currently assigned to THYSSENKRUPP INDUSTRIAL SOLUTIONS AG. The applicant listed for this patent is THYSSENKRUPP INDUSTRIAL SOLUTIONS AG. Invention is credited to Holger Thielert.
Application Number | 20140352207 14/350758 |
Document ID | / |
Family ID | 47022619 |
Filed Date | 2014-12-04 |
United States Patent
Application |
20140352207 |
Kind Code |
A1 |
Thielert; Holger |
December 4, 2014 |
PROCESS FOR DRY COOLING OF COKE WITH STEAM WITH SUBSEQUENT USE OF
THE SYNTHESIS GAS PRODUCED
Abstract
A method for the dry quenching of coke using steam with
subsequent use of the synthesis gas generated, the method involving
the cyclic coking of coal to coke with the coke being sent to a
quenching device after being discharged from the coke oven and
steam being introduced into the quenching device for dry quenching,
thus creating synthesis gas made up of carbon monoxide (CO) and
hydrogen (H.sub.2) via a water-gas reaction, and the synthesis gas
produced being fed to a further application. This method allows the
heat generated during coking to be used for the production of
useful synthesis gas which, in turn, can be used for a further
purpose or in the heating process, thus on the whole achieving an
extremely even energy balance throughout the entire process.
Inventors: |
Thielert; Holger; (Dortmund,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THYSSENKRUPP INDUSTRIAL SOLUTIONS AG |
Essen |
|
DE |
|
|
Assignee: |
THYSSENKRUPP INDUSTRIAL SOLUTIONS
AG
Essen
DE
|
Family ID: |
47022619 |
Appl. No.: |
14/350758 |
Filed: |
September 22, 2012 |
PCT Filed: |
September 22, 2012 |
PCT NO: |
PCT/EP2012/003969 |
371 Date: |
April 9, 2014 |
Current U.S.
Class: |
44/607 |
Current CPC
Class: |
C10K 3/006 20130101;
Y02P 20/129 20151101; C10B 49/02 20130101; C01B 3/56 20130101; C01B
3/12 20130101; C10B 39/02 20130101; C01B 2203/0283 20130101; C01B
2203/043 20130101; C10K 3/00 20130101; C10B 39/00 20130101 |
Class at
Publication: |
44/607 |
International
Class: |
C10B 39/00 20060101
C10B039/00; C10B 49/02 20060101 C10B049/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2011 |
DE |
10 2011 115 698.8 |
Claims
1. Method for the dry quenching of coke in which coal is heated in
a coke oven via heating by means of a high calorific gas and coke
is obtained via cyclic coking, said coke being pushed out into a
coke quenching car on completion of the coking, and the
incandescent coke is transported to a coke quenching device in a
coke quenching car in which said incandescent coke is quenched to a
temperature below the kindling temperature by means of a quenching
gas, wherein gaseous steam (H2O) is used as the quenching gas under
the exclusion of air, said steam reacting at least partially with
the incandescent coke according to the water-gas reaction to form
synthesis gas made up of hydrogen (H2) and carbon monoxide (CO),
and due to the dry quenching being carried out in a coke quenching
device the hydrogenous quenching gas obtained is collected, and the
gas mixture thus obtained is used for a further purpose.
2. Method for the dry quenching of coke according to claim 1,
wherein use for a further purpose relates to the gas mixture being
added to the fuel gas of the coke oven(s).
3. Method for the dry quenching of coke according to claim 2,
wherein a hydrocarbonaceous fuel gas is mixed with the synthesis
gas used to heat the coke oven before it is added to the coke
oven.
4. Method for the dry quenching of coke according to claim 3,
wherein the fuel gas is natural gas.
5. Method for the dry quenching of coke according to claim 3,
wherein the fuel gas is coke oven gas.
6. Method for the dry quenching of coke according to claim 1,
wherein the synthesis gas is subjected to a heat recovery process
before being used for a further purpose.
7. Method for the dry quenching of coke according to claim 6,
wherein steam is generated during the heat recovery process.
8. Method for the dry quenching of coke according to claim 1,
wherein use for a further purpose relates to conversion of the
carbon monoxide (CO) contained in the gas mixture using steam
(H2O), said carbon monoxide (CO) being converted to carbon dioxide
(CO2).
9. Method for the dry quenching of coke according to claim 8,
wherein use for a further purpose relates to conversion of the
carbon monoxide (CO) using steam (H2O) and subsequent purification
of the hydrogen (H2) obtained in a pressure-swing adsorption
unit.
10. Method for the dry quenching of coke according to claim 1,
wherein the steam for quenching is split into at least two part
streams, with one part stream of the steam being fed into the coke
quenching device from below in a vertically upward flow direction
and a further part stream of the steam being fed into a part of the
coke quenching device in which the coke to be quenched has a
temperature of 500 to 900.degree. C.
11. Method for the dry quenching of coke according to claim 1,
wherein the coke quenching device is a coke quenching shaft.
12. Method for the dry quenching of coke according to claim 1,
wherein the coke quenching device is a coke quenching chamber.
13. Method for the dry quenching of coke according to claim 12,
wherein the coke quenching chamber is equipped with an antechamber.
Description
[0001] The invention relates to a method for the dry quenching of
coke by means of steam with subsequent use of the synthesis gas
generated, said method involving the cyclic coking of coal to coke
with the coke being sent to a quenching device after being
discharged from the coke oven and steam being introduced into the
quenching device for dry quenching, thus creating synthesis gas
made up of carbon monoxide (CO) and hydrogen (H.sub.2) via a
water-gas reaction, and the synthesis gas produced being fed to a
further application. This method allows the heat generated during
coking to be used for the production of useful synthesis gas which,
in turn, can be used for a further purpose or used in the heating
process, thus on the whole achieving an extremely even energy
balance throughout the entire process.
[0002] Most methods for the production of coke take place in large
coke oven batteries or coke oven banks that comprise conventional
coke oven chambers or coke oven chambers of the "heat recovery" or
"non-recovery" type. In conventional coke oven chambers the coking
gas is collected and processed, while the coking gas in "heat
recovery" or "non-recovery"-type coke oven banks is combusted in
the coke oven in order to heat said oven. Here, in many embodiments
the heating of the coke oven is carried out in several steps in a
gas space above the coke cake and in a coke oven sole below the
coke oven chamber.
[0003] The coking process is performed cyclically, the cycles being
charging, coking, discharging and quenching. After coking, the coke
is pushed out of the coke oven chamber at a temperature of
approximately 1100.degree. C. It is pushed out into a quenching car
that collects the coke cake and transports it to a quenching
device. In many embodiments this is a wet quench tower, where the
coke cake is sprayed with water which evaporates and cools the coke
cake to a temperature below the kindling temperature of the coke so
that it can be transported in the open air without posing a hazard.
After quenching, the temperature of the coke is unevenly
distributed in the coke cake but is usually less than 100.degree.
C.
[0004] DE19614482C1 gives one embodiment of a wet quench tower.
This teaching describes a plant for the wet quenching of hot coke
in a process for the coking of coal using a coke sluice and a coke
transfer chute that is located in a quench tower with a water feed
device. On the other side, the chute fits onto a coke quenching car
equipped at the bottom end with a coke discharge device and water
discharge flaps. The water feed system is located directly at the
transfer chute and empties into the coke quenching car, which can
be sealed watertightly, and said car is equipped with a control
system which keeps the coke discharge flaps closed watertightly
while the water is being fed in and opens the water discharge flaps
once the water feed has been completed. When water is used for
quenching, all of the thermal energy stored in the coke cake is
lost without being used.
[0005] For this reason, increasing efforts have recently been made
to dry quench hot coke using gases instead of water. Here, the
gases are passed through the hot coke and collected or extracted
until the coke has cooled to a temperature below its kindling
temperature. The hot gas is usually passed through a heat recovery
unit in which steam is generated, thus recovering the thermal
energy. In turn, the steam can be used to drive auxiliary units or
to generate electric power. For these purposes, inert gases, such
as nitrogen or blast furnace gas, are often used.
[0006] WO9109094B1 describes a method for the dry quenching of coke
in a quenching chamber with the aid of circulating quenching gas,
said method allowing the velocity of the gas corning from the coke
to be adjusted so that the grain size of the entrained coke dust
particles is less than 3 mm and when the hot quenching gas enters
the waste heat recovery boiler the grain size of the entrained coke
dust is less than 1 mm, said method involving this gas being passed
through a device that consists of a quenching chamber and an
antechamber with a round cross section of about equal size and a
cylindrical outer casing made of metal, and in particular the roof
of the quenching chamber being in an inclined position so that it
rises to the hot gas channel, thus increasing the cross section of
the annular gas channel above the coke pile enough to allow the gas
velocity of the hot quenching gas to be adjusted during quenching
so that it remains virtually uniform across the length.
[0007] WO8602939A1 describes a method for dry coke quenching using
quenching gas, said method involving the coke and the quenching gas
being fed in countercurrent direction through a two-stage quencher,
the first stage involving quenching to coke temperatures of
approximately 800.degree. C. and the quenching gas fed through the
second quenching stage containing steam, the quenching gas loop
thus being directly coupled with a thermal treatment step in which
steam is added so that there is essentially no char burnout, which
is achieved by the quenching in the first quenching stage taking
place solely by indirect heat exchange between the coke and a
coolant via heat exchanger walls and the quenching in the second
stage being carried out solely by means of the steam-containing
quenching gas.
[0008] State-of-the-art methods for dry coke quenching may include
a variety of embodiments. EP0317752A2 describes a method for
improving the performance of coke dry quenchers which involves hot
coke being broken up before entering the quenching shaft.
DE3030969A1 describes a method for the dry quenching of hot raw
coke that is pushed out of the chambers of a coke oven battery and
discharged in a quenching chamber, where it is quenched by means of
direct or indirect contact, or both, with a quenching agent, and
therefore the raw coke is preclassified into two or more size
fractions before entering the quenching chamber and the individual
size fractions are subjected to quenching in separate quenching
chambers.
[0009] Further embodiments relate to the heat recovery or cleaning
of the quenching gas. DE2435500A1 describes a method for preheating
coking coal using superheated waste heat steam which is generated
in a dry coke quencher by the coke releasing, at its highest
temperature level, some of its heat to the walls of a steam jacket.
DE3217146A1 describes a device for dedusting the loop gas of a coke
dry quencher in which the gas inlet channel and the gas outlet
channel are located at right angles to each other, the gas outlet
channel being directly connected, via a conical expansion, with the
inlet opening of the waste heat recovery boiler integrated into the
gas loop and a dust collection chamber with an inclined dust
discharge area being positioned on the opposite side to the gas
inlet channel.
[0010] However, the said methods and their embodiments have the
disadvantage that during quenching the heat of the coke either
cannot be recovered or the heat of the coke can only be
inefficiently recovered as during quenching a large gas volume is
generated and this needs to be passed through a heat recovery unit,
making quenching technically difficult or economically inefficient.
For this reason, it would be advantageous to utilise the heat that
exists in the pushed coke via an endothermic chemical reaction that
makes this energy available in chemical form.
[0011] One suitable endothermic chemical reaction is the water-gas
reaction with the corresponding water-gas equilibrium. To carry out
this reaction, steam (H.sub.2O) is passed through the hot coke,
which reacts with the steam (H.sub.2O) to form hydrogen (H.sub.2)
and carbon monoxide (CO). This reaction is endothermic and
reads:
C+H.sub.2OH.sub.2+CO; .DELTA.H=+131.3 kj/mol
[0012] An additional reaction between the steam and the coke to
form carbon dioxide and two equivalents of hydrogen is possible but
according to the invention it does not generally take place due to
suitable metering and a suitable gas velocity of the steam. This
reaction is strongly endothermic and can only be carried out with
additional heating of the coke.
[0013] GB347601A describes a method for the production of a gas
mixture made up of nitrogen and hydrogen which is suitable for the
synthesis of ammonia and which is produced in a coke quenching
device in which the coke is sprayed with water and permeated by air
and in which the carbon monoxide is directed into a plant section
in which the carbon monoxide is converted into an equivalent of
hydrogen via a subsequent conversion of the carbon monoxide using
steam. Here, the steam for converting the carbon monoxide comes
from the water that is sprayed into the coke cake in order to
quench the coke. The application does not describe quenching the
coke cake with permeating gaseous steam.
[0014] Therefore, the objective is to provide a method that
cyclically carbonises coal and uses gaseous steam (H.sub.2O) to dry
quench hot coke after a coking cycle, with the steam (H.sub.2O)
thus reacting at least partially with the coke to form hydrogen
(H.sub.2) and carbon monoxide (CO) according to the water-gas
equilibrium, the hydrogen (H.sub.2) obtained being collected and
the gas mixture thus obtained being used for a further purpose. In
this way synthesis gas is obtained.
[0015] According to the invention, coke quenching using steam takes
place in a quenching device that is preferably designed as a
quenching shaft. Following coking of the coal and completion of the
coking process, the coke cake is taken to, or tipped onto, a
quenching car, which transports the coke cake to the quenching
device. Here, the coke cake is sealed off from the surrounding
atmosphere and gaseous steam is passed through it. Preferably, this
is done in a vertically upward gas flow direction so that the
specifically heavier steam is displaced by the lighter hydrogen
during the quenching process. The steam may be a gas mixture in any
state and even be in a mixture with other gases, but it is
preferably used in pure form.
[0016] What is claimed in particular is a method for the dry
quenching of coke, in which [0017] coal is heated in a coke oven
via heating by means of a high calorific gas and coke is obtained
via cyclic coking, said coke being pushed out into a coke quenching
car on completion of the coking, and [0018] the incandescent coke
is transported to a coke quenching device in a coke quenching car
in which said incandescent coke is quenched to a temperature below
the kindling temperature by means of a quenching gas,
[0019] and said process being characterised in that [0020] gaseous
steam (H.sub.2O) is used as the quenching gas under the exclusion
of air, said steam reacting at least partially with the
incandescent coke (C) according to the water-gas reaction to form
synthesis gas made up of hydrogen (H.sub.2) and carbon monoxide
(CO), and [0021] due to the dry quenching being carried out in a
coke quenching device the hydrogenous quenching gas obtained is
collected, and [0022] the gas mixture thus obtained is used for a
further purpose.
[0023] The synthesis gas generated may also contain impurities, but
if the reaction is carried out correctly, it consists mainly of the
constituents hydrogen (H.sub.2) and carbon monoxide (CO).
[0024] For implementing the method the steam is preferably
generated in a steam boiler. Said steam is kept hot through
suitable possibilities for intermediate storage and is then fed
into the coke quenching device under pressure using a metering
device. In order to prevent condensation of the steam on
introduction into the coke quenching device, the feed pipes can, in
an advantageous embodiment, be heated. When the steam reacts with
the hot coke, hydrogen (H.sub.2) and carbon monoxide (CO) are
produced. In a preferred embodiment the gaseous steam used is dry,
i.e. there are no adhering water droplets or mist. Via the method
according to the invention the thermal energy of the coke that is
released during quenching following the coking process is used to
generate useful products. As a result, the energy balance of the
overall coke production process can be improved.
[0025] The synthesis gas generated and the hydrogen contained
therein can be used for any further purpose. In one embodiment of
the invention use of this gas mixture for a further purpose
involves it being added to the fuel gas of the coke oven(s). In
this way, the coke oven is heated with the gas generated during
quenching of the coke. For this, the hydrogen used to heat the coke
oven can be mixed with a hydrocarbonaceous fuel gas before being
fed to the coke oven. In an exemplary embodiment the fuel gas is
natural gas. In a further embodiment, the fuel gas is coke oven
gas. It is also possible to use blast furnace gas from a blast
furnace process as the fuel gas instead of a hydrocarbonaceous fuel
gas.
[0026] In an further embodiment the synthesis gas is subjected to a
heat recovery process before being used for a further purpose or
being fed to the coke oven for heating purposes. This may, for
example, be achieved by passing the gas through a waste heat
recovery boiler. In one embodiment of the invention steam is
generated during the heat recovery process. In a typical embodiment
the steam is then used to generate mechanical energy by driving a
turbine. This can, in turn, be used to generate electric power. It
is also possible to direct the synthesis gas generated through a
heat exchanger in which the steam used for quenching is preheated
in countercurrent direction.
[0027] In a further embodiment of the invention a water-gas shift
reaction is carried out to convert the carbon monoxide (CO) into
carbon dioxide (CO.sub.2) after the coke has been quenched with
steam (H.sub.2O). As a result, a gas mixture is obtained. This gas
mixture mainly consists of hydrogen (H.sub.2) and carbon dioxide
(CO.sub.2) and can be easily converted into pure hydrogen, for
example by means of pressure-swing adsorption. Here, in one
embodiment the steam required for this can be added in excess to
the quenching process or added to the synthesis gas already
generated. It may also be sprayed in as liquid water after the coke
has been quenched.
[0028] In a further embodiment of the invention use for a further
purpose relates to a conversion of the carbon monoxide with steam
and subsequent purification of the hydrogen obtained during the
conversion in a pressure-swing adsorption unit. The hydrogen can
then be used, for example, in a chemical process in a subsequent
application. Pressure-swing adsorption units for the purification
of hydrogen from hydrogenous gases are well-known in the state of
the art. WO2006066892A1 teaches one example of a method for
purifying hydrogen by means of pressure-swing adsorption.
[0029] In a further embodiment of the invention the steam is split
into at least two part streams for quenching. In one embodiment of
the invention a part stream of the steam is introduced into the
coke quenching device from below in a vertically upward flow
direction and a further part stream of the steam is fed into a part
of the shaft in which the coke to be quenched has a temperature of
500 to 900.degree. C. This may, for example, be done via feed
nozzles installed in the side of the shaft that inject the steam
directly into the coke.
[0030] In one exemplary embodiment of the invention the coke
quenching device is a coke quenching shaft. In a further exemplary
embodiment of the invention the coke quenching device is a coke
quenching chamber. In addition, this may, for example, be equipped
with an antechamber. The quenching device or the subsequent
transfer line for the hydrogen may also be equipped with a
dedusting device. This allows the dust to be reduced if a
dust-laden coal is used or large amounts of dust are created during
quenching.
[0031] For it to be used in implementing the method, the coke oven
battery or coke oven bank may be of any design and configured in
any way. The coke oven battery from which the coke comes and which
is heated by the synthesis gas may, for example, be a coke oven
battery in which the coking gas is collected and processed. The
coke oven bank from which the coke comes may, for example, be a
"heat-recovery"-type coke oven battery. Finally, the coke oven bank
from which the coke comes may also be a "nonrecovery"-type coke
oven battery. Even the coke ovens that are located in a coke oven
battery or bank may ultimately be of any design as long as they are
suitable for the production of coke and for being heated by
synthesis gas when appropriate. The coke pushing may also be
carried out at a different coke oven battery or bank from that to
which the synthesis gas obtained during quenching is fed, but this
is not usual practice.
[0032] Furthermore, auxiliary equipment, such as storage tanks for
liquids or gases, pumps, valves, heating or quenching equipment,
knock-out drums or meters for measuring temperatures or
concentrations of gas constituents may be used at any point in the
method according to the invention.
[0033] The invention has the advantage of utilising the thermal
energy of the coke after coking by means of an endothermic chemical
reaction and so the thermal energy of the hot coke can be utilised
much better than in prior-art methods. Furthermore, the invention
has the advantage of providing hydrogen as a useful product without
the addition of further energy, thus allowing the energy balance of
the overall method to be improved. The environmental compatibility
of this method can thus be considerably improved.
[0034] The invention is further explained by means of a drawing,
this drawing merely representing an exemplary embodiment and not
being limited thereto.
[0035] FIG. 1 shows a coke oven which serves to carbonise coal. It
depicts the coke oven chamber (1) with the coal cake (2), the coke
oven chamber doors (3), the primary heating space (4) above the
coke cake (2) and the secondary heating space (5) below the coke
cake (2). The quenching car (6), which collects the coke cake (2)
for quenching, is parked in front of the coke oven chamber (1).
Said quenching car (6) is brought in front of the coke quenching
chamber (7) and the coke cake (2) is emptied into the coke
quenching chamber (7) via a feed flap (7a). Said flap (7a) is
closed once the coke quenching chamber (7) has been filled. Steam
(8, H.sub.2O) then flows into the coke quenching chamber (7) from
below and reacts with the hot coke cake (5a) according to the
water-gas equilibrium to form hydrogen and carbon monoxide (9,
H.sub.2 and CO) as synthesis gas. The steam (8) is generated via a
steam boiler (10) with a downstream metering device (10a). The
synthesis gas (9) generated during quenching is extracted in an
upwards direction and, following dedusting in a dedusting unit
(11), it is directed into the secondary heating space (5) of the
coke oven (1) as fuel gas (9a). This is done via a heat exchanger
(12), which, in countercurrent direction, preheats the steam (8)
fed in to quench the coke (2). Here, it is added to the partially
combusted coking gas which has already flowed into the secondary
heating space (5) from the primary heating space (4) and combusted.
As a result, it contributes to the heating of the coke cake (2)
through the floor of the coke oven chamber (1). After combustion,
the fully combusted coking gas is exported out of the secondary
heating space (5) as waste gas (13) and sent to a gas scrubbing
device (14). The cleaned waste gas (14a) is exported from the gas
scrubbing device (13) and sent to a heat recovery unit (15). Here,
a generator (15a) that generates electric power is driven via a
turbine. The cooled waste gas (15b) is exported via a flue (16).
The quenched coke (5a) or the coke to be quenched (5a) is
discharged via a discharge flap (7b) and sent for final
quenching.
LIST OF REFERENCE NUMBERS AND DESIGNATIONS
[0036] 1 Coke oven chamber [0037] 2 Coal or coke cake [0038] 3 Coke
oven chamber doors [0039] 4 Primary heating space [0040] 5
Secondary heating space [0041] 5a Coke to be quenched [0042] 6
Quenching car [0043] 7 Coke quenching chamber [0044] 7a Feed flap
[0045] 7b Discharge flap [0046] 8 Steam [0047] 9 Synthesis gas
[0048] 9a Fuel gas for the secondary heating space [0049] 10 Steam
boiler [0050] 10a Control valve for steam [0051] 11 Storage tank
[0052] 12 Heat exchanger [0053] 13 Waste gas [0054] 14 Gas
scrubbing device [0055] 14a Cleaned waste gas [0056] 15 Heat
recovery unit [0057] 15a Generator [0058] 15b Cooled waste gas
[0059] 16 Flue
* * * * *