U.S. patent application number 13/496986 was filed with the patent office on 2012-10-25 for method for the combined residue gasification of liquid and solid fuels.
This patent application is currently assigned to THYSSENKRUPP UHDE GMBH. Invention is credited to Adrian Brandl, Christoph Hanrott, Max Heinritz-Adrian.
Application Number | 20120266539 13/496986 |
Document ID | / |
Family ID | 43603419 |
Filed Date | 2012-10-25 |
United States Patent
Application |
20120266539 |
Kind Code |
A1 |
Hanrott; Christoph ; et
al. |
October 25, 2012 |
METHOD FOR THE COMBINED RESIDUE GASIFICATION OF LIQUID AND SOLID
FUELS
Abstract
A process for joint entrained-bed gasification of ash-containing
solid fuels and liquid fuels which are fed separately of each other
to the coal gasification reactor via several burners, said burners
having a concentric firing angle of greater than 0 degree such that
soot formation is reduced and the conversion efficiency is
increased, and the solid is conveyed to the gasification reactor
together with an inert gas, and at least part of the ash-containing
solid fuel contains fine coal particles which originate from coal
mining and are not suited for fixed-bed gasification, and the
liquid ash-containing fuel contains residues from a fixed-bed
gasification.
Inventors: |
Hanrott; Christoph;
(Muenster, DE) ; Heinritz-Adrian; Max; (Muenster,
DE) ; Brandl; Adrian; (Schwerte, DE) |
Assignee: |
THYSSENKRUPP UHDE GMBH
Dortmund
DE
|
Family ID: |
43603419 |
Appl. No.: |
13/496986 |
Filed: |
September 9, 2010 |
PCT Filed: |
September 9, 2010 |
PCT NO: |
PCT/EP2010/005542 |
371 Date: |
April 24, 2012 |
Current U.S.
Class: |
48/210 |
Current CPC
Class: |
C10J 2300/0936 20130101;
C10J 2300/0959 20130101; C10J 3/721 20130101; C10J 2300/093
20130101; C10J 3/506 20130101; C10J 2300/1223 20130101; C10J
2300/0933 20130101; C10J 2300/0989 20130101 |
Class at
Publication: |
48/210 |
International
Class: |
C10J 3/00 20060101
C10J003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2009 |
DE |
10 2009 041 854.7 |
Claims
1. Process for the recovery of syngas by the gasification of
ash-containing liquid residues from a fixed-bed gasification at a
pressure of 0.3 to 8.0 MPa and a temperature above 1400.degree. C.
using oxygen-containing gaseous gasification agents in a cooled
reactor, characterised in that the ash-containing liquid fuel is
fed to the reactor together with an ash-containing solid fuel, and
the liquid and the solid fuel are fed to the reactor separately via
several burner systems, and the liquid and the solid fuel are fed
to the reactor secantly to the circumference of the reactor at a
firing angle above 0.degree., and the ash-containing solid fuel,
dispersed in a carrier gas is fed to the reactor, and the
ash-containing solid fuel constitutes at least part of the portion
of fine coal particles from coal mining which cannot be used for
fixed-bed gasification.
2. Process according to claim 1, characterised in that the residue
product from the fixed-bed gasification contains hydrocarbons, in
particular tars, but also phenols, fatty acids and ammonia.
3. Process according to claim 1, characterised in that carbonaceous
solid fuel is a coal of a fine grain size, preferably below 5 mm,
which cannot be used in a fixed-bed gasification.
4. Process according to claim 1, characterised in that the burner
system for the supply of the ash-containing liquid fuel consists of
three tubes arranged concentrically, oxygen or an oxygen-containing
gas being conveyed through the inner and the outer tube of the
burner system and the ash-containing liquid fuel being conveyed
through the central annular gap formed by the inner and the outer
tube.
5. Process according to claim 4, characterised in that the burner
system including the three tubes concentrically arranged has a
conically tapered end and is equipped with a cooling chamber in the
area of the burner outlets.
6. Process according to claim 1, characterised in that the
carbonaceous fuel is supplied via two or more burner systems facing
each other and, staggered by 90 degrees in relation to these in the
horizontal, the ash-containing liquid fuel is supplied via two or
more burner systems facing each other.
7. Process according to claim 1, characterised in that the burner
systems are distributed over one or several horizontal planes.
8. Process according to claim 1, characterised in that the firing
angle between the discharge direction of the fuel and the
connection line between the burner nozzle and the axis of symmetry
of the reactor is 3-6.
9. Process according to claim 1, characterised in that the firing
angle opposite the horizontal plane is greater than 0 degree.
10. Process according to claim 9, characterised in that the
transport gas consists of 100% or less of nitrogen or carbon
dioxide or a combination of both gases.
Description
[0001] The invention relates to a process for the simultaneous
gasification of solid fuels and ash-containing liquid fuels under
pressure, the solid fuel and the liquid fuel being fed separately
of each other to the gasification reactor and the ash content of
both fuels being discharged from the reactor as molten slag at a
temperature above 1500.degree. C.
STATE OF THE ART
[0002] Since many years different gasifier types have been known
for the gasification of solid carbonaceous fuels under pressure.
The best known processes are fixed-bed, fluidised-bed and
entrained-bed gasification. Before the 80s gasification project
designs had almost exclusively been based on the fixed-bed
gasification process whereas today's units are usually designed as
entrained-bed gasifiers. Most of the installed fixed-bed gasifiers
are still in operation today.
[0003] In comparison to today's entrained-bed gasification
processes the fixed-bed gasification has some disadvantages, such
as increased water and space requirement and the more complex gas
and water treatment. Furthermore, in fixed-bed gasification, tar
oils with fine-grained ash particles are obtained as liquid residue
product. These residues may in addition contain phenols, fatty
acids, heavy metals, ammonia and other impurities. Therefore, the
residues must be treated in a complex way. Furthermore, in coal
mining large amounts of fine coal particles are obtained (approx.
20-30% of the total amount of coal). This fine coal dust cannot be
used for fixed-bed gasification at all or only after complex
treatment. In most cases, however, these residues are not useful in
the generation of syngas and are passed to a simple combustion
unit.
[0004] As mentioned in DE 42 26 034 B4 and DE 43 17 319 C1, the
liquid residues from the fixed-bed gasification are passed as
slurry to the entrained-bed gasification. A technical solution for
the gasification of residues in the entrained-bed gasification is
not mentioned. An optional utilisation of fine coal particles
obtained from coal mining is not mentioned either.
[0005] The abstract of DE 42 26 015 C1 mentions the direct process
coupling of fixed-bed gasification and oil gasification. However,
the oil gasification is only rated for liquid hydrocarbons of a
very low concentration of solids or ash, well below one percent by
weight. The liquid residues of the fixed-bed gasification, however,
contain up to 10% solid particles. The gasification temperatures in
the oil gasification are considerably below those of an
entrained-bed gasification of coal. This means that any ash
particles contained in the fuel continue to be separated as ash and
must be disposed of in a complex way. Temperatures above
1400.degree. C., preferably above 1500.degree. C., are required for
a separation of the ash particles contained in the residues in
molten state from the fixed-bed gasification. The bricklining of
the oil gasification unit and the downstream syngas cooling units
are not designed for such temperatures.
[0006] Thus, only the coal gasification process is suited for a
gasification of the residues including the withdrawal of the molten
slag. As mentioned in DE 38 20 013 A1, there are coal gasification
processes using either a bricklined or a cooled reactor. As
explained in DE 38 20 013 A1, a gasifier equipped with a bricklined
reactor is also not suited for the gasification of dust-containing
tar residues because the forming liquid slag infiltrates and
destroys the refractory masonry of the reactors, in particular, in
the case of high concentrations of heavy metals or alkali metals in
the residues.
[0007] Therefore, it is suggested in DE 38 20 013 A1 to degas the
dust-containing tar residues in a gasifier equipped with a cooled
reactor vessel, the tar residues being fed--independently of the
burner--to the reactor together with the steam, i.e. not in a
burner having its own oxygen supply. In this process, however, the
input of liquid residues is very limited. In addition, in this
process, a considerably lower conversion efficiency is to be
expected because there is no intensive mixing of the tar residues
and the oxygen.
[0008] A further disadvantage of the processes described in DE 42
26 034 C1 and DE 43 17 319 B4 is the limited ash concentration in
the fuel. The solid fuel is fed to the gasifier as a fuel/water
mixture. The supplied water and the ash content must be brought to
the required gasifier temperature with the aid of the energy
released in fuel gasification. With high ash contents, however, the
energy released by gasification is no longer sufficient to maintain
the gasifier temperature. As, however, high-ash coal is used in
particular in fixed-bed gasification, the combination of an
entrained-bed gasification with coal/water supply is very
limited.
[0009] In addition, the problem of a possible soot formation in the
gasification of liquid hydrocarbons is not mentioned in none of the
patents. As the downstream plant sections of the coal gasification
are not rated for a higher soot load, an increased soot formation
would result in considerable problems in these plant sections.
Objectives
[0010] It is therefore the target and objective of the invention to
flexibly use the ash-containing liquid residues from a fixed-bed
gasification and the fine coal particles which cannot be used in a
fixed-bed gasification jointly in an entrained-bed gasification and
to simultaneously minimise soot formation.
[0011] The invention achieves the objective by a process according
to the features of the first claim.
[0012] The dependent claims disclose an advantageous embodiment of
the claims.
[0013] The inventive solution provides a process for the recovery
of syngas by the gasification of ash-containing liquid residues
from a fixed-bed gasification at a pressure of 0.3 to 8.0 MPa and a
temperature above 1400.degree. C. using oxygen-containing gaseous
gasification agents in a cooled reactor,
in which [0014] the ash-containing liquid fuel is fed to the
reactor together with an ash-containing solid fuel, and [0015] the
liquid and the solid fuel are fed separately to the reactor via
several burners, and [0016] the liquid and the solid fuel are fed
to the reactor secantly to the circumference of the reactor at a
firing angle above 0.degree., and [0017] the ash-containing solid
fuel, dispersed in a supplied gas, is fed to the reactor, and
[0018] the ash-containing solid fuel constitutes at least part of
the portion of fine coal particles from coal mining which cannot be
used for fixed-bed gasification.
[0019] Normally, coal lumps from coal mining are gasified in a
fixed-bed gasification. Fine coal particles below 5 mm cannot be
gasified in the fixed-bed gasification and must be gasified in a
different way or disposed of. The fixed-bed gasification
additionally yields a mixture of condensates as residue, said
mixture containing mainly phenols, fatty acids, ammonia, tar oils
and medium-heavy oils as well as ash-containing and carbonaceous
solid particles. The residue must be treated in a complex way such
that it can be passed to further use if required or be disposed
of.
[0020] Thus, economic operation of a fixed-bed gasification
requires a flexible use of the solid and liquid residues obtained
from fixed-bed gasification. For this, an entrained-bed
gasification with cooled reactor and a separate supply of the
ash-containing liquid and solid fuels, the latter being conveyed in
a transport gas, is an ideal solution. In an optional embodiment
the transport gas consists of 100% or less nitrogen or carbon
dioxide or a combination of both gases.
[0021] The cooled reactor can be operated at temperatures above
1400.degree. C., preferably above 1500.degree. C. such that the
ash-containing fuel particles0 can be discharged as granulated
slag. The slag requires no further treatment because possible
impurities are not washed out in contrast to the ash in the
fixed-bed gasification. Moreover, the cooled reactor is resistant
to any impurities contained in the fuels, e.g. heavy metals.
[0022] The separate supply of the solid and liquid fuels
facilitates the optimum use of the fuels. Typically, the
carbonaceous solid fuel is a coal of a fine grain size, preferably
below 5 mm, which cannot be used in a fixed-bed gasification.
Therefore, the fine coal particles from coal mining which are not
suitable for fixed-bed gasification can advantageously be used for
being conveyed in a transport gas since a diameter below 0.1 mm is
required for conveying the coal in a transport gas. This reduces
the normal expenditure by coal grinding. Moreover, the separate
supply of the solid fuel facilitates a compensation of possible
variances in quality or quantity of the liquid fuel. Moreover,
additional coal may be mixed to the solid fuel to increase the
overall performance.
[0023] On the other hand, a burner which largely reduces soot
formation may be used for the ash-containing liquid fuel. Such a
burner is described in EP 00 95 103 A1. This burner consists of
three tubes arranged concentrically which form a central supply
tube and two enclosing annular gaps, the liquid fuel being supplied
via the central annular gap formed by the inner and the outer tube.
The oxygen or oxygen-containing gas is supplied via the supply tube
and the outer annular gap. In a typical embodiment the burner
system consists of three concentric tubes with conically tapered
end finely distributing the escaping fuel upon exit. This increases
the conversion efficiency and thus reduces soot formation to a
minimum. The burner system can be equipped with a cooling chamber
in the area of the burner outlet.
[0024] The carbonaceous solid fuel is preferably conveyed via two
burner systems facing each other and, staggered by 90 degrees in
relation to these in the horizontal, the ash-containing liquid fuel
is also supplied via two burner systems facing each other. Of
course, the burner systems may also be provided in any other number
and thus also be staggered by an angle greater or smaller than 90
degrees. Burner planes arranged in parallel are also feasible for
performance adaptation.
[0025] A further reduction of soot formation is achieved by all
burners having a firing angle greater than 0 degree and preferably
3-6 degrees, a swirl thus being created inside the reactor. This
increases, on the one hand both the residence time and the
conversion efficiency, the firing angle being the angle between the
discharge direction of the fuel and the horizontal connection line
between the burner nozzle and the axis of symmetry of the reactor.
The discharge direction of the fuel may also be inclined towards
the horizontal if necessary. On the other hand, the separation of
the molten slag and of the non-converted carbon particles towards
the reactor wall is intensified. There, the non-converted carbon
particles are further converted or retained in the slag.
[0026] It is also possible to provide several horizontal planes for
the burners. Hence, the burner systems can be distributed over one
or several horizontal planes. Normally, the firing angle relative
to the horizontal plane is 0 degree. However, it is also possible
that the firing angle relative to the horizontal plane is greater
than 0 degree.
EMBODIMENT EXAMPLES
[0027] The following example is to explain the invention. The
embodiment example is shown in FIGS. 1 to 3 and detailed in the
following sections. FIG. 1 shows an inventive process of a
fixed-bed and an entrained-bed gasification. FIG. 2 shows the
lateral and vertical view of a gasifier including burners for solid
and liquid fuels. FIG. 3 shows a burner suited for running the
inventive process. The drawings only show embodiment examples of
the invention, the invention not being restricted to these
embodiment examples.
[0028] In a preferred embodiment, the residues of a fixed-bed
gasification are conveyed to an entrained-bed gasifier. Here, the
residues are a liquid tar/fine coal mixture obtained as residue
from the fixed-bed gasification and non-usable fine coal particles
from coal mining.
[0029] Every hour 400 t/h of coal are extracted from a coal mine
(1), FIG. 1. Of these, approx. 280 t/h of lumpy coal (1a) are
suited for fixed-bed gasification (2). Synthesis gas (2a) is
produced in the fixed-bed gasification (2). The remaining fine coal
(1b) has a diameter lower 5 mm and cannot be used for fixed-bed
gasification (2). The remaining 120 t/h of fine coal (1b) are
conveyed to the entrained-bed gasification (3) and there converted
to synthesis gas (3a). In addition, the fixed-bed gasification (2)
yields approx. 95 t/h of fine-coal-containing tar oils to be
further conveyed (2b) to the entrained-bed gasification (3). The
solid carbon content of the tar oils is approx. 5%. The amount of
energy of 95 t/h of the residue product roughly corresponds to 25%
of the amount of energy supplied to the fixed-bed gasification via
the 280 t/h of lumpy coal.
[0030] Thus, the total amount of synthesis gas produced can be
increased by the described combination of fixed-bed and
entrained-bed gasification from 270,000 Nm.sup.3/h to 490,000
Nm.sup.3/h.
[0031] In the preferred embodiment, FIG. 2, the residues from the
fixed-bed gasification and the fine coal are fed separately via
four burners to the gasification reactor (4) of the entrained-bed
gasifier. Two burners are provided for the solid fuel (5a,5c) and
two burners for the liquid fuel (5b,5d). All burners (5a-d) are in
a horizontal plane, two burners each facing each other. The burners
are designed in such a manner that the fuel escapes from the
burners (10) secantly to the circumference of the reactor, the
firing angle (9) between the discharge direction of the fuel (11)
and the connection line between the burner nozzle and the axis of
symmetry of the reactor being greater than 0 degree, preferably 3-6
degrees.
[0032] FIG. 3 shows the preferred burner for the gasification of
the tar oils of fine coal content. This burner consists of three
tubes arranged concentrically (6,7,8) which form a central supply
tube (6) and two enclosing annular gaps (7,8), the liquid fuel
being supplied via the central supply tube (6). The fuel is
supplied via the annular gap (7). The oxygen-containing gas is
supplied via outer supply tube (8). The three tubes have a
conically tapered end finely distributing the escaping fuel upon
exit. This increases the conversion efficiency and reduces soot
formation to a minimum.
LIST OF REFERENCES USED
[0033] 1 Coal mine [0034] 1a Lumpy coal [0035] 1b Fine coal [0036]
2 Fixed-bed gasification [0037] 2a Synthesis gas [0038] 3
Entrained-bed gasification [0039] 3a Synthesis gas [0040] 4
Gasification reactor [0041] 5a-d Burners [0042] 6 Central supply
tube [0043] 7 Annular gap [0044] 8 Outer supply tube [0045] 9
Firing angle [0046] 10 Transversal discharge [0047] 11 Radial
discharge
* * * * *