U.S. patent application number 12/085398 was filed with the patent office on 2010-02-11 for combustion installation.
Invention is credited to Tor Bruun, Stellan Hamrin.
Application Number | 20100031859 12/085398 |
Document ID | / |
Family ID | 37811282 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100031859 |
Kind Code |
A1 |
Bruun; Tor ; et al. |
February 11, 2010 |
Combustion Installation
Abstract
A combustion installation comprising a combustion device for
combustion of a fuel and an oxygen-containing gas to a combustion
gas and a method for such combustion is described. A nozzle means
is arranged for injection of the fuel into the combustion device
and a membrane device for supplying oxygen to the combustion gases
for production of the oxygen-containing gas, wherein the combustion
device comprises at least a first inlet for the oxygen-containing
gas and an outlet for the combustion gases. The combustion
installation comprises at least a first ejector including the
nozzle means and the first inlet, wherein the nozzle means and the
first inlet are arranged to drive the flow of oxygen containing gas
and fuel through the combustion device.
Inventors: |
Bruun; Tor; (Porsgrunn,
NO) ; Hamrin; Stellan; (Kungsor, SE) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
37811282 |
Appl. No.: |
12/085398 |
Filed: |
November 23, 2006 |
PCT Filed: |
November 23, 2006 |
PCT NO: |
PCT/EP2006/068851 |
371 Date: |
October 23, 2009 |
Current U.S.
Class: |
110/205 ;
110/297; 122/4D |
Current CPC
Class: |
F23C 2900/09002
20130101; Y02E 20/344 20130101; Y02E 20/32 20130101; F02C 3/20
20130101; F23C 2900/13002 20130101; Y02E 20/34 20130101; B01D
2257/104 20130101; F23L 7/007 20130101; F23C 13/00 20130101; B01D
53/22 20130101; F23L 2900/07001 20130101; Y02E 20/322 20130101;
F02C 3/32 20130101; F02C 3/34 20130101; F23C 9/00 20130101 |
Class at
Publication: |
110/205 ;
110/297; 122/4.D |
International
Class: |
F23C 9/00 20060101
F23C009/00; F23L 7/00 20060101 F23L007/00; F23C 13/06 20060101
F23C013/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 23, 2005 |
SE |
0502571-3 |
Claims
1-7. (canceled)
8. A combustion installation, comprising: a combustion device with
an inner space that combusts a fuel and an oxygen containing gas to
a combustion gas, wherein the combustion device comprises: a first
inlet for the oxygen containing gas, an outlet for the combustion
gases, and a catalyst arranged between a nozzle device that injects
the fuel into the inner space of the combustion device and the
outlet of the combustion device; a membrane device that supplies
oxygen to the combustion gases for production of the
oxygen-containing gas, wherein the membrane device is arranged
between the outlet of the combustion device and the first inlet of
the combustion device so that the combustion gases are arranged to:
be directed from the outlet of the combustion device into the
membrane device, and be supplied with oxygen and be directed back
to the first inlet of the combustion device as a oxygen-containing
gas; and an ejector arranged to maintain the circulation of
combustion gas, where the fuel is included in the primary flow of
the ejector and the combustion gas is the secondary flow.
9. The combustion installation according to claim 8, wherein the
primary flow is fuel.
10. The combustion installation according to claim 9, wherein the
combustion device comprises a second inlet.
11. The combustion installation according to claim 10, wherein a
second inlet comprises part of a second ejector.
12. The combustion installation according to claim 11, wherein the
primary flow for the second ejector comprises the outlet flow from
first ejector.
13. The combustion installation according to claim 10, wherein the
first inlet and the second inlet are arranged such that at least
half of the gas from the membrane device is directed into the
second inlet.
14. The combustion installation according to claim 10, wherein the
first inlet and the second inlet are arranged such that 50 to 80
percent of the gas from the membrane device is directed into the
second inlet.
15. The combustion installation according to claim 14, wherein the
first inlet and the second inlet are arranged such that 55 to 65
percent of the gas from the membrane device is directed into the
second inlet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the U.S. National Stage of International
Application No. PCT/EP2006/068851, filed Nov. 23, 2006 and claims
the benefit thereof. The International Application claims the
benefits of Swedish application No. 0502571-3 filed Nov. 23, 2005.
Both of the applications are incorporated by reference herein in
their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a combustion installation
comprising a combustion device and a membrane device arranged to
separate oxygen from a gas mixture.
BACKGROUND OF THE INVENTION
[0003] It is desirable to decrease unwanted exhausts from
combustion installations and it is for instance desirable to reduce
nitrogen oxides as far as possible.
[0004] It is also desirable to decrease exhausts of carbon dioxide
that is produced during combustion. It is possible to separate
carbon dioxide from a combustion gas but as the concentration of
carbon dioxide usually is low and as the combustion gas comprises
other components, such as oxygen and nitrogen, it is relatively
complicated to separate the carbon dioxide from the combustion
gas.
[0005] One possibility to facilitate the separation of carbon
dioxide is to perform the combustion in another medium than air,
from which medium carbon dioxide more easily can be separated. If
air is not used as combustion medium it is necessary to provide
oxygen to the medium. It is, however, relatively expensive to
provide pure oxygen in the necessary volumes. One possibility for
providing oxygen is to use a suitable membrane which is arranged to
separate oxygen from a gas mixture, which gas mixture usually is
air.
[0006] Such membranes are described in U.S. Pat. No. 5,118,395. A
combustion cycle using an ejector to mixed fuel with air or pure
oxygen is known from instants from EP 1 095 202 A1, EP 0 141 594 A2
and WO 96/01968 A1
[0007] One type of such membranes is called "mixed conducting
membrane (MCM)". This type of membrane device comprises an MCM
material and works without a voltage being applied. Such a membrane
device works through the partial pressure of oxygen being lower on
the side of the filter to which oxygen is transported. Oxygen ions
are here directed in the one direction through the membrane and
electrons are directed back through the membrane in the opposite
direction.
[0008] EP-A-658,367 describes as well different types of such
membranes. This document describes different combustion
installations with a membrane device from which oxygen is
extracted. The oxygen-depleted gas which is produced in the
membrane device is led to one or more combustion devices and
combustion gases from the combustion devices are used to drive a
turbine.
[0009] The Norwegian published patent application NO-A-972,631
describes the use of an MCM in combustion processes. According to
the described processes compressed air is directed to an MCM
reactor. The MCM reactor comprises a membrane device, which
separates oxygen from the air. The air from which oxygen has been
separated is led away via a heat exchanger. The separated oxygen is
used during combustion and combustion. The combustion gases
comprise mainly steam and carbon dioxide. The steam may be
condensed which makes it possible to separate the carbon dioxide.
As nitrogen essentially not takes part in the combustion process
the exhaust of unwanted nitrogen oxides is avoided. The diluted
air, heated by heat exchange expands in the turbine, which
generates power output.
[0010] In the PCT application WO 01/92703 a combustion installation
is described in which fuel is combusted without nitrogen. A
compressor is arranged to compress air to create a first flow of
compressed air. The first flow of compressed air from the
compressor passes an MCM reactor in which the compressed air is
heated by a second flow of combustion gases, and oxygen from the
air is transported over to the other flow of combustion gases. The
combustion gases which have been cooled off and to which oxygen has
been added are led back to a combustion chamber. In the combustion
chamber fuel is added which is combusted with the oxygen, which was
added from the air in the MCM reactor. The flow of air in the MCM
reactor is counter-current to the flow of combustion gases. The
PCT-application WO 2004/094909 describes a method and a device for
operating a burner of a heat engine, especially a gas turbine. A
first oxygen-enriched carrier gas flow called a first oxidizer
mixture is provided, to which the fuel is admixed so as to form a
first fuel/oxidizer mixture, and a second oxygen enriched carrier
gas flow called a second oxidizer mixture is provided. The first
fuel-oxidizer mixture is catalyzed so as to form a catalyzed first
fuel/oxidizer mixture in which the fuel is at least partly
oxidized. The catalyzed first fuel/oxidizer mixture is mixed with
the second oxidizer mixture in order to form a second fuel/oxidizer
mixture, which is ignited and burned.
[0011] To maintain circulation of this gas mixture, some kind of
pumping de-vice is needed. It is a technical problem to find a
suitable equipment for this, mainly because of the high temperature
of the gas. Above documents do not take into account this
problem.
[0012] The ejector in a system works as a compressor. An ejector
has no moving parts, there is no greasing needed, which means that
an installation in a high temperature environment is
favourable.
[0013] The ejector consists of a suction manifold, a pipe ending
with a nozzle, a mixing chamber and a diffuser.
[0014] The gas, which is to be pumped, flows through the suction
manifold. A narrow pipe, in which the fuel or fuel mixture flows,
is preferably placed concentrically in the suction manifold. Both
these parts of the ejector discharge preferably concentrically into
the mixing chamber, whereas the narrow pipe ends with a nozzle.
[0015] Attached to and downstream the mixing chamber follows the
diffuser as the finishing component of the ejector.
[0016] The nozzle could be of subsonic, sonic or supersonic (Laval)
type. The ejector is the part of a system, where the colder high
pressure fuel, called primary flow, actuating fluid or suction
flow, mixes with the hot low pressure recycle gas, which is called
secondary flow, induced fluid or injection flow.
[0017] The main tasks of the ejector are to maintain the pressure
needed by the system to re-circulate a specific secondary mass flow
for a re-forming process.
[0018] The pressure of the recycle gas is affected by pressure
losses in the system. These losses are compensated by the pressure
increase in the ejector. The primary high pressure fluid expands
supersonically out through the nozzle (for the nozzle designed as a
Laval nozzle) to the mixing chamber.
[0019] This causes suction in the suction manifold, which entrains
the secondary low pressure flow into the mixing chamber. Now the
primary flow transfers part of its momentum (m-v) to the secondary
flow and the two flows mix until uniformity in reference to
velocity, pressure, temperature and chemical composition is
reached. This mixed high speed flow enters the diffuser, where part
of the kinetic energy is converted into pressure with the aim to
reach a higher pressure value than at the recycle inlet. The mixing
chamber could be designed on the basis of two principles: constant
area mixing or constant pressure mixing. In the first case the
cross sectional area of the mixing chamber is hold constant from
inlet of the mixing tube to the diffuser inlet. In the second case
they hold the pressure constant along the mixing chamber length
which causes a convergent chamber profile.
SUMMARY OF INVENTION
[0020] The invention is to arrange at least one ejector in order to
pump the flow of an oxygen containing gas through the described
combustion installation.
[0021] According to a first aspect of the present invention a
combustion installation is provided, comprising a combustion device
with a space for combustion of a fuel and an oxygen-containing gas
as combustion gas, a nozzle means for injection of the fuel into
the inner space of the combustion device, and a membrane device for
supplying oxygen to the combustion gases for production of the
oxygen-containing gas. The combustion device further comprises at
least a first inlet for the oxygen-containing gas, an outlet for
the combustion gases and a catalyst arranged between the nozzle
means and the outlet of the combustion device. The membrane device
is arranged between the outlet of the combustion device and the
first inlet of the combustion device so that the combustion gases
are arranged to be directed from the outlet of the combustion
device into the membrane device, be supplied with oxygen and be
directed back to the first inlet of the combustion device as the
oxygen-containing gas. The combustion installation is characterised
in that it comprises at least a first ejector arranged to pump the
flow of combustion gases
[0022] With a combustion installation according to the present
invention flow of the oxygen containing gas is provided through the
injection of fuel or a mixture of fuel and a carrying gas. Thus, no
additional device is required in order to provide the flow of the
oxygen containing gas through the combustion device.
[0023] The use of an ejector to inject the fuel into the inner
space of the combustion device also provides for a fast and
efficient mixing of the fuel with the oxygen containing gas.
[0024] The combustion device may be arranged to inject a carrier
gas together with the fuel into the inner space of the combustion
device. By arranging the nozzle means in this way it is possible to
alter the speed of the flow without altering the amount of fuel
being injected through the nozzle means. The carrier gas is
preferably a gas which does not take part in the combustion and may
e.g. be steam.
[0025] In case the nozzle means comprises a plurality of nozzles,
each nozzle may form part of an ejector. The flows from the
different ejectors are then combined into a common flow through the
combustion de-vice. The inner space between the catalyst and the
outlet of the combustion device may form a combustion compartment
for combustion of the fuel and the oxygen-containing gas.
[0026] The combustion device may comprise a second inlet being
connected to the outlet of the membrane device, wherein the second
inlet is arranged next to the combustion device. With a second
inlet more efficient combustion of the fuel and the
oxygen-containing gas may be achieved. It is then possible to allow
only a part of the oxygen-containing gas to be mixed with the fuel
and to pass the catalyst.
[0027] The combustion installation may comprise at least a second
ejector including the second inlet. In this way the flow of the
oxygen containing gas from the second inlet may be driven by the
flow of gas from the first ejector.
[0028] The combustion device may comprise a length axis which
extends from the second inlet of the combustion device to the
outlet of the combustion device, wherein the second inlet is
ring-formed and en-circles the length axis.
[0029] The first inlet and the second inlet may be arranged so that
at least half of the gas from the membrane device is directed into
the second inlet. This has proved to be advantageous for the
catalytic reaction in the catalyst.
[0030] The first inlet and the second inlet are preferably arranged
so that 50 to 80 percent and most preferred 55 to 65 percent of the
gas from the membrane device is directed into the second inlet.
[0031] The membrane device may comprise a first compartment with an
inlet and an outlet and a second compartment with an inlet and an
outlet, which membrane device is arranged to allow oxygen to pass
between the first compartment and the second compartment. There are
also other ways of arranging membrane devices but the described way
of arranging the membrane device is the conventional way of
arranging membrane devices in. The purpose of the membrane device
is, however, for the first compartment to be separated from an
oxygen reservoir using an oxygen-transparable membrane. Arranging
the second compartment with an inlet and an outlet makes it
possible to arrange for the oxygen-containing gas to flow through
the second compartment and thereby allowing oxygen to be
transported over to the compartment.
[0032] The first inlet of the combustion device and the outlet of
the combustion device may be connected to the outlet of the first
compartment of the membrane device and the inlet of the first
compartment of the membrane device, respectively, wherein the
membrane device is arranged in such a way that an oxygen-containing
gas, which passes the second compartment of the second membrane
device is heated by the combustion gas passing the first
compartment of the membrane device and which has been heated during
combustion of the fuel in the said combustion device and in such a
way that oxygen passes from the second compartment of the membrane
device to the first compartment of the membrane device.
[0033] The combustion device may comprise a first heat exchanger
comprising a first and a second compartment, wherein the outlet of
the combustion device is connected to the inlet of the first
compartment of the membrane device via the first compartment of the
first heat exchanger. By arranging such a heat exchanger effective
heat exchanging is possible between the first compartment and the
second compartment at the same time as a part of the heat
exchanging may take place outside the membrane device. As the
membranes, that are used in membrane devices, usually are very
expensive, it is de-sirable to limit the size of the membrane. As
the effectiveness of the membrane usually is dependent on the
temperature and as too high temperatures may damage the membrane it
is desirable to avoid excessively high or excessively low
temperatures in the membrane device. By arranging the first heat
exchanger connected to the outlet of the combustion device the
combustion gases will be cooled before they reach the membrane
device. This decreases the risk of too high temperatures in the
membrane device.
[0034] The combustion installation may comprise a second heat
exchanger comprising a first and a second compartment, wherein the
first inlet of the combustion device is connected to the outlet of
the first compartment of the membrane device via the first
compartment of the second heat exchanger. In this way a higher
temperature is achieved in the membrane device thereby an increased
efficiency of the oxy-gen transport in the membrane device is
achieved.
[0035] It is possible to have only the second heat exchanger and to
dispose with the first heat exchanger.
[0036] The second compartment of the first heat exchanger may be
connected to the outlet of the second compartment of the membrane
device. In this way combustion gases will flow in the
counter-current direction to the air which is heated by the
combustion gases and which passes the second compartment of the
heat exchanger
[0037] The following preferred embodiments of the invention will be
described with reference to the appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1 shows schematically a combustion installation with a
compressor, turbine and a generator according to an embodiment of
the present invention. FIG. 2 shows in great detail a combustion
device FIG. 3 shows schematically a combustion installation with a
compressor, turbine and a generator according to an alternative
embodiment of the present invention.
[0039] FIG. 4 shows a schematic picture of an ejector and its main
components.
DETAILED DESCRIPTION OF INVENTION
[0040] In the following description of preferred embodiments of the
invention similar parts in the different figures will be denoted
with the same reference numeral.
[0041] In FIG. 1 a combustion installation 1 is shown partly in
cross-section. The combustion installation 1 comprises a combustion
device 2 with an inner space 3 for combustion of the fuel and an
oxygen-containing gas to a combustion gas in order to produce heat.
A fuel supply pipe 4 is connected to the combustion device. The
combustion device 2 comprises a first inlet 5 for the
oxygen-containing gas and an outlet 6 for combustion gases. In FIG.
1 an optional second inlet 30 to the combustion device 2 is also
shown. The combustion installation 1 also comprises a membrane
device 7, which is shown in cross-section in FIG. 1. The membrane
device 7 comprises a first compartment 8 with an inlet 9 and an
outlet 10 and a second compartment 11 with an inlet 12 and an
outlet 13. An oxygen-permeable membrane 29 divides the first
compartment 8 of the membrane device 7 from the second compartment
1 1 of the membrane device 7. The outlet 10 of the first
compartment 8 of the membrane device 7 is connected to the first
inlet 5 of the combustion device 2 via a combustion gas pipe 15.
The outlet 6 of the combustion device 2 is correspondingly
connected to the inlet 9 of the first compartment 8 of the membrane
de-vice 7 via an oxygen gas pipe 14. The combustion installation 1
comprises a compressor 16 being connected to the inlet 12 of the
second compartment 11 of the membrane device 7 via an air supply
pipe 17. The combustion installation further comprises a turbine
18, which is connected to the outlet 13 of the second compartment
11 of the membrane device 7 via a pipe 19. The compressor 16
comprises a compressor inlet 20. The turbine 18 comprises a shaft
21, which is arranged to drive the compressor 16 and a generator
22. A bleed off pipe 23 for draining a part of the combustion gases
is connected to the combustion pipe 14 and to a cooler 24. The
cooler 24 comprises a cooling-water inlet 25 and a cooling-water
outlet 26. The cooler 24 also comprises a condensed-water outlet 28
for water in the corn bustion gases which has condensed in the
cooler 24 and a carbon dioxide outlet 27 for carbon dioxide which
has been separated from the combustion gases. The function of the
cooler 24 will not be described in detail here as coolers 24 in
which carbon dioxide and water are separated are well-known from
the art.
[0042] During operation the turbine 18 drives the compressor 16 and
the generator 22. The compressor 16 takes in air through the
compressor inlet 20. The air is compressed in the compressor 16 and
is di-rected by the air supply pipe 17 to the inlet 12 of the
second compartment 11 of the membrane device 7. When the compressed
air passes the second compartment 11 of the membrane device 7 the
air will be heated by the combustion gases passing the first
compartment 8 of the membrane device 7. When the compressed air
passes the second compartment 11 of the membrane device 7 oxygen in
the air will pass the membrane 29 into the first compartment 8 of
the membrane device 7. Combustion gases which are transported into
the first compartment 8 of the membrane device 7 via the inlet 9
will be supplied with oxygen and thereby be transformed into an
oxygen-containing gas while simultaneously being cooled off by the
air passing though the second compartment 11 of the membrane device
7.
[0043] The oxygen-containing gas is transported from the outlet 10
of the first compartment 8 of the membrane device 7 via pipe 15 to
the combustion device 2. Fuel is transported into the combustion
device 2 through the fuel supply pipe 4. The fuel, which is
injected into the combustion device 2 through the fuel supply pipe
4, is injected in a first ejector, which pumps the
oxygen-containing gas into the combustion device 2. After the
oxygen-containing gas has been mixed with fuel which has been
transported through the fuel-supply pipe 4 combustion of the fuel
with oxygen takes place so that combustion gases are formed. The
main part of the combustion gases are directed via the combustion
gas pipe 14 back into the membrane de-vice 7 through the inlet 9 of
the first compartment 8 of the membrane device 7. However, material
is added to the combustion gases through the injection of fuel in
the combustion device 2. In order to keep the pressure in the
combustion gas pipe 14 constant over time part of the combustion
gases must be directed away through the bleed off pipe 23. The
combustion gases in the bleed off pipe 23 are directed to the
cooler 24, where the combustion gases are cooled off using cooling
water, which passes the cooler 24 from the cooling water to the
cooling water outlet 26.
[0044] The air passing the second compartment 11 of the membrane
device 7 will be heated by the combustion gases passing the first
compartment 8 of the membrane device 7. The flow direction of air
in the membrane device 7 is preferably counter-directed to the flow
direction of the combustion gases. Thus, the highest temperature in
the first compartment 8 and the highest temperature in second
compartment 11 are found in the same end of the membrane device 7.
The flows in the different compartments of the membrane device 7
are preferably chosen so, that they are essentially equally big.
This means that the combustion gases are cooled down to the order
of same temperature as the temperature of the compressed air at the
inlet 12 of the second compartment 11 of the membrane device 7. The
heated air leaving the outlet 13 of the second compartment 11 of
the membrane device 7 is directed via the turbine pipe 19 to the
turbine 18, where the heated air drives the turbine 18, which in
turn drives the compressor 16 and the generator 22.
[0045] The oxygen-containing gas leaving the outlet 10 of the first
compartment 8 of the membrane device 7 is directed to the first
inlet 5 of the combustion device 7 and the second inlet 30 of the
combustion device in case it exists. The combustion device 2 will
now be described in further detail with reference to FIG. 2.
[0046] In FIG. 2 the combustion device 2 is shown in cross-section.
A nozzle means 31 in the form of a nozzle is arranged at the first
inlet 5. The nozzle means 31 is connected to the fuel supply pipe
4, which in turn is connected to the fuel tank (not shown). The
first inlet 5 and the second inlet 30 are connected to the
oxygen-containing gas pipe 15. A catalyst 32 is arranged after
diffuser 33. The pipe 37 is the mixing chamber for mixing of the
fuel and the oxygen-containing gas. Before outlet (6) is a
combustion compartment 34 for combustion of the fuel and the
oxygen-containing gas. The combustion arrangement de-scribed forms
an ejector 46 as a pump device.
[0047] It is possible to arrange the nozzle means to inject a
carrier gas together with the fuel. The carrier gas is preferably a
gas which does not take part in the reaction. The carrier gas may
be e.g. steam. By altering the flow of the carrier gas the pump
effect of the ejector 46 may be altered without altering the amount
of fuel being injected into the combustion device 2. Thus, the flow
speed in the combustion device 2 may be altered independently from
the amount of fuel being injected into the combustion device 2.
[0048] The second inlet 30 is arranged downstream the catalyst 32
between the catalyst 32 and the outlet 6 of the combustion device
2. Between the catalyst 32 and the combustion compartment 34 there
is an outlet compartment 50 having a outlet 36.
[0049] The combustion installation forms a second ejector 47
including the outlet 36 and the second inlet 30.
[0050] The first inlet 5 and the second inlet 30 are arranged in
such a way that 50 to 80 percent and preferably 35 to 65 percent of
the oxygen-containing gas is directed into the second inlet.
Accordingly 20 to 50 percent and preferably 35 to 45 percent of the
oxygen-containing gas is directed into the first inlet 5.
[0051] FIG. 3 shows an alternative configuration of combustion
installation 1, where heat exchange between the compressed air and
the circulating gas from the combustion device 2 is showed as
separate heat exchangers. Only differences between the combustion
installation 1 in FIG. 1 and the combustion installation 1 in FIG.
3 will be described. The combustion installation 1 comprises a
first heat exchanger 40 with a first compartment 41 and a second
compartment 42. The outlet 6 of the combustion device 2 is
connected to the inlet 9 of the first compartment 8 of the membrane
device 7 via the first compartment 41 of the first heat exchanger
40. Correspondingly the outlet 13 of the second compartment 11 of
the membrane device 7 is connected to turbine pipe 19 via the
second compartment 42 of the first heat exchanger 40.
[0052] The combustion installation 1 comprises a second heat
exchanger 43 with a first compartment 44 and a second compartment
45. The first inlet 5 of the combustion device 2 is connected to
the outlet 9 of the first compartment 8 of the membrane device 7
via the first compartment 44 of the second heat exchanger 43.
Correspondingly the inlet 12 of the second compartment 11 of the
membrane device 7 is connected to the air supply pipe 17 via the
second compartment 45 of the second heat exchanger 43.
[0053] When the combustion gases pass the first compartment 41 of
the first heat exchanger 40 the combustion gases will be cooled
down as heat is transferred to the air passing the second
compartment 42 of the first heat exchanger 40. The combustion gases
that come in contact with the membrane 29 are thereby cooled down.
Correspondingly heat will be transferred from the combustion gases
pass-ing the first compartment 44 of the second heat exchanger by
air passing the second compartment 45 of the second heat exchanger
43.
[0054] The above-described embodiments may be modified in many ways
without departing from the spirit and the scope of the present
invention. For example it is not necessary to have both a first
inlet and a second inlet into the combustion device.
[0055] FIG. 4 shows the main components of an ejector. Fuel inlet
pipe 51 ends in direction of flow with a nozzle 52. The primary
flow of an ejector goes through this pipe and nozzle. The
oxygen-containing gas in above described combustion installation is
the secondary flow of an ejector and goes through suction manifold
53. The mixing of primary flow and secondary flow takes place in
the mixing-chamber 54. The pressure recover of the gas mixture from
mixing-chamber 54 takes place in the diffuser 55.
* * * * *