U.S. patent application number 14/508049 was filed with the patent office on 2015-05-14 for process for processing inorganic matter containing residue.
This patent application is currently assigned to INEOS BIO SA. The applicant listed for this patent is INEOS BIO SA. Invention is credited to Peter Simpson Bell, Dustin Freyaldenhoven.
Application Number | 20150129178 14/508049 |
Document ID | / |
Family ID | 51982760 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150129178 |
Kind Code |
A1 |
Bell; Peter Simpson ; et
al. |
May 14, 2015 |
PROCESS FOR PROCESSING INORGANIC MATTER CONTAINING RESIDUE
Abstract
A process and system provide for processing inorganic
matter-containing residue in a thermal decomposition process. The
process and system are effective for reducing pressures which can
occur during processing of inorganic matter-containing residue. A
process for processing inorganic matter-containing residue in a
thermal decomposition process includes conveying inorganic matter
containing residue from a thermal decomposition unit to a burn-out
section and conveying the inorganic matter containing residue from
the burn-out section through a transition section to an ash sump.
The inorganic matter containing residue is cooled to remove about
10% or more of heat in the inorganic matter containing residue
before reaching the ash sump. The process further includes
contacting the inorganic matter containing residue with a cooling
medium in the gas sump and venting gaseous material generated back
to the thermal decomposition unit.
Inventors: |
Bell; Peter Simpson;
(Dunblane, GB) ; Freyaldenhoven; Dustin; (Vero
Beach, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INEOS BIO SA |
Dolle |
|
CH |
|
|
Assignee: |
INEOS BIO SA
Rolle
CH
|
Family ID: |
51982760 |
Appl. No.: |
14/508049 |
Filed: |
October 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61907232 |
Nov 21, 2013 |
|
|
|
61902520 |
Nov 11, 2013 |
|
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Current U.S.
Class: |
165/104.31 ;
165/104.11 |
Current CPC
Class: |
F28C 3/06 20130101; C10J
3/84 20130101; C10J 2300/1807 20130101; C10J 2200/154 20130101;
C10J 2300/0976 20130101; C10J 2300/1628 20130101; C10J 3/002
20130101 |
Class at
Publication: |
165/104.31 ;
165/104.11 |
International
Class: |
C10J 3/84 20060101
C10J003/84; F28C 3/06 20060101 F28C003/06 |
Claims
1. A process for processing inorganic matter-containing residue in
a thermal decomposition process, the process comprising: conveying
inorganic matter containing residue from a thermal decomposition
unit to a burn-out section; conveying the inorganic matter
containing residue from the burn-out section through a transition
section to an ash sump, wherein organic matter containing residue
is cooled to remove about 10% or more of heat in the inorganic
matter containing residue before reaching the ash sump; contacting
the inorganic matter containing residue with a cooling medium in
the ash sump, wherein a gaseous material is generated; and venting
the gaseous material back to the thermal decomposition unit.
2. The process of claim 1 wherein the burn-out section is effective
for reducing an amount of carbon in the inorganic matter containing
residue.
3. The process of claim 1 wherein inorganic matter containing
residue is conveyed through the transition section with an ash
ram.
4. The process of claim 1 wherein the inorganic matter containing
residue is cooled by spraying a cooling medium onto the inorganic
matter containing residue in the transition section.
5. The process of claim 4 wherein the cooling medium is water.
6. The process of claim 3 where the ash ram is moved at a rate
effective for allowing inorganic matter containing residue to cool
to about 2700.degree. F. or less.
7. The process of claim 3 wherein the ash ram is moved for about 2
to about 5 seconds and then paused for about 8 to about 15
seconds.
8. The process of claim 1 wherein the gaseous material includes
steam.
9. The process of claim 8 wherein a ratio of an amount of steam
vented back to the thermal decomposition unit to steam added to the
thermal decomposition unit from other sources is about 0.6 to 1 or
less.
10. The process of claim 8 wherein a ratio of ash generated to
steam generated is about 2:1 to about 6:1.
11. The process of claim 1 wherein a ratio of ash generated to
cooling medium applied is about 2:1 to about 10:1.
12. A process for reducing pressure in a thermal decomposition
unit, the process comprising: conveying inorganic matter containing
residue from a thermal decomposition unit through a transition
section into an ash sump, wherein inorganic matter containing
residue being conveyed through the transition section is contacted
with a cooling medium and conveyed through the transition section
at a rate effective for removing about 10% or more heat in the
inorganic matter containing residue before reaching the ash sump;
and venting a gaseous material from the ash sump to the thermal
decomposition unit, wherein the process is effective for
maintaining a pressure in the ash sump of about 15 inches gauge or
less of water pressure.
13. The process of claim 12 wherein inorganic matter containing
residue is conveyed through the transition section with an ash
ram.
14. The process of claim 13 where the ash ram is moved at a rate
effective for allowing inorganic matter containing residue to cool
to about 2700.degree. F. or less.
15. The process of claim 13 wherein the ash ram is moved for about
2 to about 5 seconds and then paused for about 8 to about 15
seconds.
16. The process of claim 12 wherein the cooling medium is
water.
17. The process of claim 12 wherein the ash sump includes a cooling
medium.
18. The process of claim 17 wherein the cooling medium is
water.
19. The process of claim 12 wherein the gaseous material includes
steam.
20. The process of claim 19 wherein a ratio of an amount of steam
vented back to the thermal decomposition unit to steam added to the
thermal decomposition unit from other sources is about 0.6 to 1 or
less.
21. The process of claim 19 wherein a ratio of ash generated to
steam generated is about 2:1 to about 6:1.
22. The process of claim 12 wherein a ratio of ash generated to
cooling medium applied is about 2:1 to about 10:1.
23. A system for reducing pressure in a thermal decomposition unit,
the system comprising: a burnout section configured to receive
inorganic matter containing residue; an ash ram effective moving
inorganic matter containing residue from a burnout section through
a transition section and into an ash sump; a cooling medium sprayer
configured to apply cooling medium to inorganic matter containing
residue in the transition section; and a vent line effective for
venting a gaseous material back to the thermal decomposition
unit.
24. The system of claim 23 wherein the burnout section includes one
or more addition points for addition of steam and oxygen in amounts
effective for reducing an amount of carbon in the inorganic matter
containing residue.
25. The system of claim 23 wherein the ash ram is moved at a rate
effective for allowing inorganic matter containing residue to cool
to about 2700.degree. F. or less.
26. The system of claim 25 wherein the ash ram is moved for about 2
to about 5 seconds and then paused for about 8 to about 15
seconds.
27. The system of claim 23 wherein the cooling medium is water.
28. The process of claim 23 wherein the ash sump includes a cooling
medium.
29. The process of claim 28 wherein the cooling medium is
water.
30. The process of claim 23 wherein the gaseous material includes
steam.
31. The process of claim 30 wherein a ratio of an amount of steam
vented back to the thermal decomposition unit to steam added to the
thermal decomposition unit from other sources is about 0.6 to 1 or
less.
32. The process of claim 30 wherein a ratio of ash generated to
steam generated is about 2:1 to about 6:1.
33. The process of claim 23 wherein a ratio of ash generated to
cooling medium applied is about 2:1 to about 10:1.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/902,520, filed Nov. 11, 2013 and U.S.
Provisional Application No. 61/907,232, filed Nov. 21, 2013, which
are incorporated in their entirety herein by reference.
[0002] A process provides for processing inorganic matter
containing residue during thermal decomposition of a carbonaceous
material feedstock. More specifically, the process is effective for
cooling inorganic matter containing residue and preventing pressure
build-up.
BACKGROUND
[0003] Thermal decomposition processes, often referred to as
gasification, include processes that are effective to convert
carbonaceous feedstock, such as municipal solid waste (MSW) or
coal, into a combustible gas. The gas can be used to generate
electricity, steam or as a basic raw material to produce chemicals
and liquid fuels.
[0004] The thermal decomposition process includes feeding
carbonaceous feedstock into a heated chamber (the thermal
decomposition unit or gasifier) along with a controlled and/or
limited amount of oxygen and optionally steam. In contrast to
incineration or combustion, which operate with excess oxygen to
produce CO.sub.2, H.sub.2O, SO.sub.x, and NO.sub.x, thermal
decomposition processes produce a raw gas composition that includes
CO and H.sub.2. More specifically, the thermal decomposition
process involves a partial oxidation or starved-air oxidation of
carbonaceous material in which a sub-stoichiometric amount of
oxygen is supplied to the gasification process to promote
production of carbon monoxide as described in WO 2009/154788.
Success of a gasification process greatly depends on quality of
syngas produced. Increased content of carbon monoxide (CO) and
hydrogen (H.sub.2) is desirable in syngas produced.
[0005] As feedstock is heated in a thermal decomposition process,
carbonaceous materials in the feedstock are converted into CO,
CO.sub.2 and H.sub.2. Mineral matter in the feedstock along with
any unconverted carbonaceous material or unconverted carbon form
ash. The amount and composition of ash (e.g. carbon content) can
have an impact on the smooth running of the decomposition process
as well as on the disposal of ash. Processing of hot ash may result
in steam generation and increased pressure in processing
equipment.
SUMMARY
[0006] A process and system are provided for processing inorganic
matter-containing residue in a thermal decomposition process. The
process and system are effective for reducing pressures which can
occur during processing of inorganic matter-containing residue. The
process is effective for use during start-up where inorganic matter
containing residue may have higher levels of carbon, as well as
being effective after start-up.
[0007] A process for processing inorganic matter-containing residue
in a thermal decomposition process includes conveying inorganic
matter containing residue from a thermal decomposition unit to a
burn-out section and conveying the inorganic matter containing
residue from the burn-out section through a transition section to
an ash sump. The inorganic matter containing residue is cooled to
remove about 10% or more of heat in the inorganic matter containing
residue before reaching the ash sump. The process further includes
contacting the inorganic matter containing residue with a cooling
medium in the ash sump and venting gaseous material generated back
to the thermal decomposition unit.
[0008] In another aspect, a process for reducing pressure in a
thermal decomposition unit includes conveying inorganic matter
containing residue from a thermal decomposition unit through a
transition section into an ash sump. The process includes cooling
inorganic matter containing residue being conveyed through the
transition section by contacting the inorganic matter containing
residue with a cooling medium and conveyed through the transition
section at a rate effective for removing about 10% or more heat in
the inorganic matter containing residue before reaching the ash
sump. Gaseous material generated from the ash sump is vented to the
thermal decomposition unit to maintain a pressure in the ash sump
of about 15 inches of water pressure (gauge pressure) or less.
[0009] In another aspect, a system for reducing pressure in a
thermal decomposition unit includes a burnout section configured to
receive inorganic matter containing residue; an ash ram effective
for moving inorganic matter containing residue from a burnout
section through a transition section and into an ash sump; a
cooling medium sprayer configured to apply cooling medium to
inorganic matter containing residue in the transition section; and
a vent line effective for venting a gaseous material back to the
thermal decomposition unit.
BRIEF DESCRIPTION OF FIGURES
[0010] The above and other aspects, features and advantages of
several aspects of the process will be more apparent from the
following figures.
[0011] FIG. 1 is a schematic diagram of a thermal decomposition
apparatus that includes a gasification zone and a burn-up zone.
[0012] FIG. 2 is a schematic diagram of an aspect of a thermal
decomposition apparatus that includes a gasification zone and a
burn-up zone wherein the gasification zone includes four sections
or hearths.
[0013] FIG. 3 is a schematic diagram of an aspect of a thermal
decomposition apparatus that includes a gasification zone, a
burn-up zone and a tar reduction zone wherein the gasification zone
includes five sections or hearths.
[0014] FIG. 4 illustrates material flow through a thermal
decomposition unit.
[0015] Corresponding reference characters indicate corresponding
components throughout the several views of the drawings. Skilled
artisans will appreciate that elements in the figures are
illustrated for simplicity and clarity and have not necessarily
been drawn to scale. For example, the dimensions of some of the
elements in the figures may be exaggerated relative to other
elements to help to improve understanding of various aspects of the
present process and apparatus. Also, common but well-understood
elements that are useful or necessary in commercially feasible
aspects are often not depicted in order to facilitate a less
obstructed view of these various aspects.
DETAILED DESCRIPTION
[0016] The following description is not to be taken in a limiting
sense, but is made merely for the purpose of describing the general
principles of exemplary embodiments. The scope of the invention
should be determined with reference to the claims.
Definitions
[0017] Unless otherwise defined, the following terms as used
throughout this specification for the present disclosure are
defined as follows and can include either the singular or plural
forms of definitions below defined:
[0018] The term "about" modifying any amount refers to the
variation in that amount encountered in real world conditions,
e.g., in the lab, pilot plant, or production facility. For example,
an amount of an ingredient or measurement employed in a mixture or
quantity when modified by "about" includes the variation and degree
of care typically employed in measuring in an experimental
condition in production plant or lab. For example, the amount of a
component of a product when modified by "about" includes the
variation between batches in a multiple experiments in the plant or
lab and the variation inherent in the analytical method. Whether or
not modified by "about," the amounts include equivalents to those
amounts. Any quantity stated herein and modified by "about" can
also be employed in the present disclosure as the amount not
modified by "about".
[0019] "Carbonaceous material" as used herein refers to carbon rich
material such as coal, and petrochemicals. However, in this
specification, carbonaceous material includes any carbon material
whether in solid, liquid, gas, or plasma state. Among the numerous
items that can be considered carbonaceous material, the present
disclosure contemplates: carbonaceous material, carbonaceous liquid
product, carbonaceous industrial liquid recycle, carbonaceous
municipal solid waste (MSW or msw), carbonaceous urban waste,
carbonaceous agricultural material, carbonaceous forestry material,
carbonaceous wood waste, carbonaceous construction material,
carbonaceous vegetative material, carbonaceous industrial waste,
carbonaceous fermentation waste, carbonaceous petrochemical co
products, carbonaceous alcohol production co-products, carbonaceous
coal, tires, plastics, waste plastic, coke oven tar, fibersoft,
lignin, black liquor, polymers, waste polymers, polyethylene
terephthalate (PETA), polystyrene (PS), sewage sludge, animal
waste, crop residues, energy crops, forest processing residues,
wood processing residues, livestock wastes, poultry wastes, food
processing residues, fermentative process wastes, ethanol
co-products, spent grain, spent microorganisms, or their
combinations.
[0020] The term "fibersoft" or "Fibersoft" or "fibrosoft" or
"fibrousoft" means a type of carbonaceous material that is produced
as a result of softening and concentration of various substances;
in an example carbonaceous material is produced via steam
autoclaving of various substances. In another example, the
fibersoft can include steam autoclaving of municipal, industrial,
commercial, and medical waste resulting in a fibrous mushy
material.
[0021] The term "municipal solid waste" or "MSW" or "msw" means
waste that may include household, commercial, industrial and/or
residual waste.
[0022] The term "syngas" or "synthesis gas" means synthesis gas
which is the name given to a gas mixture that contains varying
amounts of carbon monoxide and hydrogen. Examples of production
methods include steam reforming of natural gas or hydrocarbons to
produce hydrogen, the gasification of coal and in some types of
waste-to-energy gasification facilities. The name comes from their
use as intermediates in creating synthetic natural gas (SNG) and
for producing ammonia or methanol. Syngas is combustible and is
often used as a fuel source or as an intermediate for the
production of other chemicals.
[0023] "Ton" or "ton" refers to U.S. short ton, i.e. about 907.2 kg
(2000 lbs).
[0024] In addition to carbon and hydrogen, feedstocks will include
a certain quantity of inorganic incombustible material, often
referred to by the term "ash," which is separated during the
complete or partial combustion of the feedstock. At certain
temperatures, the ash may fuse to form agglomerates or "slag". The
process by which slag is formed is referred to as "slagging".
Thermal Decomposition Unit Design and Operation
[0025] Some examples of suitable thermal decomposition processes
and apparatus are provided in U.S. Ser. Nos. 13/427,144, 13/427,193
and 13/427,247, all of which were filed on Apr. 6, 2011, and all of
which are incorporated herein by reference.
[0026] Referring now to FIG. 1, the thermal decomposition apparatus
10 includes a gasification zone 103 and a burn-up zone 200. The
gasification zone may include one inlet for adding gas (e.g.,
oxygen containing gas, steam, carbon dioxide), inlet 102; and the
burn-up zone may include one inlet for adding gas, inlet 202. The
gasification zone 103 receives carbonaceous material feedstock 101.
A transfer ram 710 moves a material bed of the feedstock through
the thermal decomposition apparatus. A transfer ram face 715 may
receive gas (e.g., oxygen containing gas, steam, carbon dioxide)
and allow the gas to exit at its face.
[0027] A stream of solid ash 205 may be removed from burn-up zone
200. An ash transfer ram 720 may move ash out of the thermal
decomposition unit. An ash transfer ram face 725 may receive gas
(e.g., oxygen containing gas, steam, carbon dioxide) and allow the
gas to exit at its face. A stream of raw syngas 105 may be removed
from the gasification zone 103.
[0028] Referring now to FIG. 2, the gasification-apparatus 11
includes a gasification zone 113 and a burn-up zone 230. As shown
in this aspect, the gasification zone 113 includes four
gasification hearths: Hearth-I 310, Hearth-II 320, Hearth-III 330,
and Hearth-IV 340. In other aspects, the gasification zone may
include from 1 to 10 hearths. One or more of the gasification
hearths may include a transfer ram 710. A transfer ram face 715 may
receive gas and allow the gas to exit at its face.
[0029] Each gasification hearth includes one inlet for adding gas:
gas inlet 111 to Hearth-I, gas inlet 121 to Hearth-II, gas inlet
131 to Hearth-III, and gas inlet 141 to Hearth-IV. The burn-up zone
includes one inlet for adding gas: gas inlet 202. A carbonaceous
material feedstock 101 can be added into Hearth-I (entry hearth) of
the gasification zone 113. A stream of solid ash 205 can be removed
from the burn-up zone 230. An ash transfer ram 720 may be utilized
to move ash out of the thermal decomposition unit. An ash transfer
ram face 725 may receive gas and allow the gas to exit at its face.
A stream of raw syngas 105 can be removed from the gasification
zone 113.
[0030] Referring now to FIG. 3, the gasification-apparatus 13
includes a gasification zone 143, a burn-up zone 500, a connecting
zone or throat 300 and a tar reduction zone 400. The gasification
zone 143 includes five gasification hearths: Hearth-I 110,
Hearth-II 120, Hearth-III 130, Hearth-IV 140, and Hearth-V 150.
Each gasification hearth includes one inlet for adding gas: gas
inlet 611 to Hearth-I, gas inlet 621 to Hearth-II, gas inlet 631 to
Hearth-III, gas inlet 641 to Hearth-IV and gas inlet 651 to
Hearth-V. The burn-up zone includes one inlet for adding gas: gas
inlet 202. The connecting zone or throat 300 includes one inlet for
adding gas: gas inlet 301.
[0031] A carbonaceous material feed 101 can be added into Hearth-I
(entry hearth) of the gasification zone 143. One or more of the
gasification hearths may include a transfer ram 710. A transfer ram
face 715 may receive gas and allow the gas to exit at its face. A
stream of solid ash 205 can be removed from the burn-up zone 500.
An ash transfer ram 720 may be utilized to move ash out of the
thermal decomposition unit. An ash transfer ram face 725 may
receive gas and allow the gas to exit at its face. A stream of hot
syngas 405 can be removed from the tar reduction zone 400.
[0032] Burn-Out Section: FIG. 4 illustrates more detailed aspects
of a thermal decomposition unit. In this aspect, feedstock material
101 moves into a feed hearth 820 and then a main hearth of a
gasification zone 103. A transfer ram 710 moves material through
the gasification zone 103. A poker arm 800 may extend from the
transfer ram 710 into the material. Material moves into a burnout
section 920. Solid ash 205 is conveyed through a transition section
822 into an ash sump 860 by an ash transfer ram 720. As ash 205 is
conveyed through the transition section 822, the ash may be
contacted with a cooling medium provided from one or more cooling
medium sprayers 927. In this aspect, the process includes providing
cooling medium through the cooling medium sparger 927 at a rate of
about 5 to about 15 gallon per minute, in another aspect, about 6
to about 14 gallons per minute, in another aspect, about 7 to about
13 gallons per minute, in another aspect, about 8 to about 12
gallons per minute, and in another aspect, about 9 to about 11
gallons per minute.
[0033] In another aspect, the amount of cooling medium sprayed onto
ash is a function of the amount of ash generated. In this aspect, a
ratio of ash generated (in pounds per hour) to cooling medium
applied (in gallons per hour) is about 2:1 to about 10:1, in
another aspect, about 3:1 to about 9:1, in another aspect, about
4:1 to about 8:1, and in another aspect, about 5:1 to about
7:1.
[0034] In one aspect, feedstock material 101 follows a material
path 840 through the thermal decomposition unit. In another aspect,
gas 900 may be supplied to the transfer ram 710. Oxygen and steam
may be introduced at one or more points in the burnout section 920.
A stream of raw syngas 105 may be removed from the gasification
zone 103.
[0035] In one aspect, feedstock is moved through the burn-out
section at a rate effective for providing a retention time of
feedstock in the burn-up zone of about 0.5 hours to about 5 hours,
in another aspect, about 1 to about 4 hours, and in another aspect,
about 2 to about 3 hours. In addition to containing
non-carbonaceous mineral matter, solid ash may include unconverted
carbon or unconverted carbonaceous matter.
[0036] The burn-out section is effective for reducing an amount of
carbon in inorganic matter containing residue. In one aspect,
carbon content of said solid ash leaving the burn-out section is
less than about 10 wt %. In one aspect, carbon content of solid ash
is less than 5 wt %. In one aspect, ratio of carbon content of
solid ash to carbon content of carbonaceous material feed is less
than about 0.1. In one aspect, ratio of carbon content of solid ash
to carbon content of carbonaceous material feed is less than about
0.01.
[0037] The carbon content of ash and carbon content of carbonaceous
material feed refers to carbon or a chemical that contains carbon.
In this aspect, numerous known techniques may be utilized to
measure carbon content. Some examples of techniques that may be
used to measure carbon include and are not limited to
loss-on-ignition (LOI) tests, thermogravimetric analysis (TGA),
laser probe based optical methods, methods using microwave
radiation, methods using nuclear magnetic resonance (NMR), and
various ASTM methods (see for example ASTM D6316).
[0038] Raw syngas is produced that may include carbon monoxide (CO)
and carbon dioxide (CO.sub.2). It is desirable to have more CO and
less CO.sub.2 in the raw syngas. In one aspect, the CO/CO.sub.2
molar ratio in said raw syngas is greater than about 0.75. In one
aspect, the CO/CO.sub.2 molar ratio in said raw syngas is greater
than about 1.0. In one aspect, CO/CO.sub.2 molar ratio in said raw
syngas is greater than about 1.5. Hot syngas may include carbon
monoxide (CO) and carbon dioxide (CO.sub.2). It is desirable to
have more CO and less CO.sub.2 in the hot syngas. In one aspect,
the CO/CO.sub.2 molar ratio in said hot syngas is greater than
about 0.75. In one aspect, the CO/CO.sub.2 molar ratio in said hot
syngas is greater than about 1.0. In one aspect, CO/CO.sub.2 molar
ratio in said hot syngas is greater than about 1.5.
[0039] Transition Section and Ash Sump: As further shown in FIG. 4,
ash 205 is conveyed through the transition section 822 into an ash
sump 860. The ash sump 860 includes a cooling medium 922. In one
aspect, the cooling medium 922 is water. Cooling medium 922 in the
ash sump 860 is maintained at a cooling medium level 924. The
cooling medium level 924 defines an open area 827 above the cooling
medium 922. The cooling medium level 924 is effective for providing
a water seal such that any gaseous material in open section 827
cannot vent into the environment through ash sump opening 832. Ash
sump 860 includes a conveyor 947 which can continually remove wet
ash for disposal in dumpster 948.
[0040] In one aspect, the ash ram is moved at a rate effective for
allowing inorganic matter containing residue to cool to about
2700.degree. F. or less as measured at the end of the transition
section and prior to entering the ash sump. In another aspect, the
inorganic matter containing residue cools to about 2600.degree. F.
or less, in another aspect, about 2500.degree. F. or less, in
another aspect, about 2400.degree. F. or less, in another aspect,
about 2300.degree. F. or less, in another aspect, about
2200.degree. F. or less, in another aspect, about 2100.degree. F.
or less, and in another aspect, about 2000.degree. F. or less. In
another aspect, the ash ram is moved for about 2 to about 5 seconds
and then paused for about 8 to about 15 seconds, and in another
aspect, the ash ram is moved for about 3 to about 4 seconds and
then paused for about 9 to about 14 seconds. In one aspect, each
ram push or ash ram frequency is about 1 push or less per hour, and
in another aspect, about 1 push or less every two hours.
[0041] Vent Line: As ash 205 is conveyed through the transition
section 822 and contacted with a cooling medium, the wet ash may
form a gas tight seal in transition section 822. Vent line 930 is
effective for dissipating any pressure that builds up in open area
827. Vent line 930 proceed through valve/control mechanism 940 and
allow gaseous material to vent back into the thermal decomposition
unit. In this aspect, the vent line is effective for maintaining a
pressure in the ash sump of about 15 inches gauge or less of water
pressure, in another aspect, the vent line is effective for
maintaining a pressure in the ash sump of about 10 inches gauge or
less of water pressure, and in another aspect, the vent line is
effective for maintaining a pressure in the ash sump of about 5
inches gauge or less of water pressure. Venting back to the thermal
decomposition unit is important as the gaseous material being
vented back may include CO and ash.
[0042] In one aspect, application of cooling medium and movement of
the ash ram is effective for providing about 500 to about 1000
pounds of steam per hour, in another aspect, about 600 to about 900
pounds of steam per hour, and in another aspect, about 700 to about
800 pounds of steam per hour. In another aspect, a ratio of an
amount of steam (in pounds per hour) vented back to the thermal
decomposition unit to a total amount of steam added to the thermal
decomposition unit from other sources (in pounds per hour) is about
0.6 to about 1 or less, in another aspect, about 0.55 to about 1 or
less, in another aspect, about 0.5 to about 1 or less, in another
aspect, about 0.4 to about 1 or less, in another aspect, about 0.3
or less, in another aspect, about 0.25 or less, and in another
aspect, about 0.1 to about 1 or less.
[0043] In another aspect, the amount of steam generated is a
function of the amount of ash generated. In this aspect, a ratio of
ash generated (in pounds per hour) to steam generated (in pounds
per hour) is about 2:1 to about 6:1, and in another aspect, about
3:1 to about 4:1.
[0044] Feedstock: In accordance with the process, the feedstock
material provided to the thermal decomposition units forms a moving
material bed inside the thermal decomposition unit. A temperature
of the material bed effects slagging. In this aspect, the process
is effective for maintaining a material bed temperature not
exceeding about 2300.degree. F. at any point in the material bed,
in another aspect, the material bed temperature does no exceed
about 2200.degree. F., in another aspect, about 2100.degree. F., in
another aspect, about 2000.degree. F., in another aspect, about
1900.degree. F., in another aspect, about 1800.degree. F., in
another aspect, about 1700.degree. F., in another aspect, about
1600.degree. F., in another aspect, about 1500.degree. F., and in
another aspect, the material bed temperature does not exceed about
1400.degree. F. Temperature may be measured by any known methods,
including for example the use of thermo-couples which are inserted
into the material bed.
[0045] Feedstock/Oxygen: A carbonaceous material feed is introduced
into the thermal decomposition unit. A first molecular oxygen
containing gas is supplied to the gasification zone and thus the
carbonaceous material feed is treated with molecular oxygen in
order to initiate and facilitate chemical transformation of
carbonaceous material. A portion of the carbonaceous material feed
is gasified produce a first gaseous product. Supply of oxygen into
the thermal decomposition unit is controlled in order to
preferentially promote formation of carbon monoxide from
carbonaceous material. A sub-stoichiometric amount of oxygen is
supplied in order to promote production of carbon monoxide. In one
aspect, oxygen is provided to the gasification zone at a rate of
about 0.5 to about 1.5 lb-mol/hr-ft.sup.2 of the thermal
decomposition bed and in another aspect, about 0.75 to about 1.25
lb-mol/hr-ft.sup.2 of thermal decomposition bed.
[0046] While the invention herein disclosed has been described by
means of specific embodiments, examples and applications thereof,
numerous modifications and variations could be made thereto by
those skilled in the art without departing from the scope of the
invention set forth in the claims.
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