CA2176617A1 - Process and apparatus for a rapid cooling of a hot gas mixture which contains hydrogen and elementary sulfur - Google Patents
Process and apparatus for a rapid cooling of a hot gas mixture which contains hydrogen and elementary sulfurInfo
- Publication number
- CA2176617A1 CA2176617A1 CA002176617A CA2176617A CA2176617A1 CA 2176617 A1 CA2176617 A1 CA 2176617A1 CA 002176617 A CA002176617 A CA 002176617A CA 2176617 A CA2176617 A CA 2176617A CA 2176617 A1 CA2176617 A1 CA 2176617A1
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- CA
- Canada
- Prior art keywords
- section
- tubes
- combustion chamber
- heat exchanger
- combustion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/0066—Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/02—Preparation of sulfur; Purification
- C01B17/04—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides
- C01B17/0404—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by processes comprising a dry catalytic conversion of hydrogen sulfide-containing gases, e.g. the Claus process
- C01B17/0413—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by processes comprising a dry catalytic conversion of hydrogen sulfide-containing gases, e.g. the Claus process characterised by the combustion step
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/02—Preparation of sulfur; Purification
- C01B17/04—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides
- C01B17/0404—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by processes comprising a dry catalytic conversion of hydrogen sulfide-containing gases, e.g. the Claus process
- C01B17/0413—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by processes comprising a dry catalytic conversion of hydrogen sulfide-containing gases, e.g. the Claus process characterised by the combustion step
- C01B17/0417—Combustion reactors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/06—Arrangements of devices for treating smoke or fumes of coolers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F27/00—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
- F28F27/02—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus for controlling the distribution of heat-exchange media between different channels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
- F28F9/22—Arrangements for directing heat-exchange media into successive compartments, e.g. arrangements of guide plates
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/30—Technologies for a more efficient combustion or heat usage
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Combustion & Propulsion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
- Treating Waste Gases (AREA)
Abstract
The combustion gas at temperatures in the range from about 1000 to 1800°C comes from the combustion chamber of a Claus process plant and immediately after the combustion chamber is conducted through an indirect heat exchanger. The first section of the indirect heat exchanger comprises numerous narrow tubes, which have a small diameter d from 5 to 50 mm and are flown through by the combustion gas. In the tubes of the first section the combustion gas is cooled to a temperature which is not in excess of 800°C within a residence time which is not in excess of 0.05 second. A succeeding second section of the heat exchanger comprises tubes which have a diameter D which is at least 2d.
Description
This invention relates to a process of cooling a combustion gas coming from a combustion chamber in which an H2S-containing gas is partially combusted at a maximum temperature in the range from about looo to 1800C to form a combustion gas that contains SO2, H2S, H2, H2O, and elementary sulfur, wherein the combustion gas immediately after it has left the combustion chamber is conducted through an indirect heat exchanger having a cooling space supplied with a cooling fluid for dissipating the heat, and to an apparatus for carrying out that process.
Such a process and the associated apparatus are known from EP-B-0 455 285. But in that case it is not desired to cool as rapidly as possible the combustion gas that has been produced in the combustion chamber for the Claus process.
In U.S. Patent 4,481,181 it is proposed that a gas mixture which has been produced by a combustion and contains hydrogen and elementary sulfur is cooled so rapidly by an admixing of cold gas that the sulfur can no longer combine or can combine only in part with the hydrogen to form H2S. For that purpose it is recommended to effect a sudden temperature drop from about 1100C to about 950C within less than 1 second.
It is an object of the invention that the combustion gas which is produced, e.g., in the combustion chamber of a Claus process plant, should rapidly be cooled in a succeeding indirect heat exchanger. That cooling should result in a cooled gas mixture which contains molecular hydrogen that has not combined with existing elementary sulfur to form H2S. In the process described first hereinbefore this is accomplished in accordance with the invention in that the combustion gas coming from the combustion chamber is first conducted in the first section of the indirect heat exchanger through numerous ~ 2176617 tubes which have a small diameter d from 5 to 50 mm and is thus cooled in the tubes of the first section to a temperature not in excess of 800C within a residence time not in excess of 0.05 second and the combustion gas coming from the narrow tubes is conducted in a second section of the indirect heat exchanger in tubes having a diameter D which is at least 2d.
In the process in accordance with the invention a single heat exchanger is preferably used, which is divided into two sections so that a most intense cooling can be effected in the first section. This permits the use of an inexpensive apparatus. Besides, the cooling conditions in the first section can be controlled substantially independently of the conditions in the second section.
In the first section of the heat exchanger the gas mixture is cooled to such a degree that the hydrogen can no longer combine with the elementary sulfur to form H2S. But a formation of condensate is avoided because it might partly clog the narrow tubes. Only in the second section, in which the tubes are much larger in diameter, is it permissible to cool to such a degree that condensate and particularly liquid sulfur is formed. It will be understood that the tubes of a section need not be perfectly uniform in diameter.
Water is usually employed as a cooling fluid in both sections of the heat exchanger and steam is produced, which in most cases is under a pressure in the range from 5 to 30 bars. On principle, other cooling fluids, such as air, may be used in the process in accordance with the invention. To still more effectively suppress the recombination of H2 and elementary sulfur to form H2S in the combustion gas being cooled, it is recommendable to cool in the tubes of the first section of the heat exchanger to a temperature not in excess of 750C within a residence time of the gas not in excess of 0.03 second. A cooling to a temperature in the range from 500 to 700C is preferably effected within that residence time.
The invention also provides a combustion chamber for a partial combustion of an H2S-containing gas at maximum ` 2176~17 .~
temperatures in the range from about 1000 to 1800C to produce a combustion gas which contains S02, H2S, H2, H2O, and elementary sulfur. An indirect heat exchanger is directly connected to the combustion chamber and comprises numerous tubes, which are flown through by the combustion gas. The heat exchanger comprises a first section and a second section, which communicates with the first section. The tubes of the first section have a small diameter d from 5 to 50 mm, and the tubes of the second section have a larger diameter D, which lo is at least 2d. The outlet ends of the tubes of the first section are disposed in the inlet region of the tubes of the - second section, and each section is provided with at least one æupply line for cooling fluid.
In the process in accordance with the invention it is possible to withdraw from the second section of the heat exchanger a gas mixture which on a dry basis contains 2 to 30%
by volume free hydrogen. In a Claus process plant that hydrogen is useful mainly for hydrogenating, and the Claus process plant is relieved from a part of the H2S which is to be reacted. This results in a considerable saving of operating costs of a Claus process plant such as is known from EP-B-0 455 285.
Further features of the process and of the apparatus will be explained with reference to the drawing, in which Figure 1 is a schematic longitudinal sectional view showing a combustion chamber and a heat e~ch~nger connected thereto, Figure 2 is a longitudinal sectional view showing the inlet portion of a tube of the first section of the heat exchanger, Figure 3 is a longitudinal sectional view showing a modified arrangement in which a plurality of tubes of the first section open into a tube of the second section of the heat exchanger, Figure 4 is an enlarged sectional view taken on line IV-IV in Figure 3, Figure 5 is an enlarged sectional view taken on line V-V in Figure 1, Figure 6 shows a heat exchanger provided with a by-pass line, and Figure 7 shows a further modification of a heat exchanger.
In accordance with Figure 1, a burner 1 of a combustion chamber 2 is supplied through line 3 with an H2S-containing gas and through line 4 with an oxygen-containing gas, such as air, oxygen-enriched air, or technically pure oxygen. In practice, a plurality of burners may be associated with a combustion chamber. The combustion space 5 in the combustion chamber 2 is defined by refractory walls because maximum combustion temperatures from about 1000 to 1800C and usually of at least 1200C will be adjusted.
Owing to the high temperatures and the simultaneous hypo-stoichiometric supply of oxygen, the combustion gas formed in the combustion space 5 contains SO2, H2O, and residual H2S and, as a result of a thermal cracking, also H2 and elementary sulfur. By a rapid cooling in the succeeding heat exchanger 6 it is ensured that the hydrogen content is not entirely eliminated by a recombination with sulfur. For that purpose the hot gases must rapidly be cooled to a temperature not in excess of 800C. That rapid cooling is effected in a first section 10 of the heat exchanger 6 in numerous narrow tubes 11, which are disposed in a first cooling space 12. A cooling fluid, particularly water, is supplied to the first cooling space 12 through line 13. Steam which has been formed is discharged through line 14. The outlet ends of the tubes 11 are held by a first tube plate 15.
Figure 2 shows the inlet end of a single tube 11, which receives in the direction indicated by the arrow 8 the hot combustion gas coming from the combustion chamber 5. A
ceramic sleeve 9 is provided for protection from the high temperatures because experience has shown that the cooling liquid which surrounds the tube 11 cannot sufficiently 217~617 effectively be cooled in that inlet region. The refractory lining defining the combustion space 5 is designated 5a.
A æecond section 20 of the heat exchanger 6 comprises a smaller number of gas-conducting tubes 21. Two or more tubes 11 of the first section are associated with each tube 21 of the second æection 20. The ratio of the diameter d of the tube 11 to the diameter D of the tubes 21 is in most cases in the range from 1:2 to 1:5. The tubes 21 of the second section extend between a second tube plate 22 and a lo third tube plate 23. A second cooling space 24 is supplied through line 25 with a cooling fluid, such as water, and steam is discharged through line 26.
The two tube plates 15 and 22 are gas-tightly interconnected by a ring 30. Besides, the exchange of liquid between the first and second cooling chambers is restricted by a perforated separating disk 31 provided between the ring 30 and the housing 7 of the heat exchanger. Because the disk 31 is permeable to the steam which has been formed, the same pressure is maintained in the two cooling spaces 12 and 24.
Furthermore, the disk 31 supports the two tube plates 15 and 22 against the housing 7.
Care is taken that the gas flowing through the tubes 11 in the first section 10 of the heat exchanger 6 will be cooled to a temperature in the range from 500 to 800C within a residence time which is not in excess of 0.05 second and preferably not in excess of 0.03 second. As is shown in the simplified Figure 1 the gas which has thus been cooled flows from two tubes 11 into one larger tube 21 of the second cooling section and is cooled further therein. The gas mixture leaving the tubes 21 first flows into a collecting chamber 28, from which any condensate which has been formed is withdrawn through line 29. Such condensate may contain, e.g., elementary sulfur. The gas which in addition to SO2, H2O, and H2S contains also molecular hydrogen finally leaves the heat exchanger 6 through a discharge line 33. The gas conducted through the discharge line 33 is usually at ~ 2176617 temperatures in the range from 200 to 400C and may be subjected to a catalystic further processing in a Claus process plant.
If it is desired to omit the two tube plates 15 and 22 shown in Figure 1 it will be possible to connect two or more tubes 11 to a larger tube 21 in the manner illustrated in Figure 3. In that case the tube 21 is provided at its inlet end with a cover 21a, through which the tubes 11 tightly extend. Figure 4 is associated with Figure 3 and a sectional view taken on line IV-IV in Figure 3 shows three tubes 11 associated with one larger tube 21. For mechanical stability a plurality of tubes 21 are supported in the housing 7 of the heat exchanger close to their covers 2la on a perforate separating wall 31, which is indicated in Figure 3.
If cooling water is used to indirectly dissipate heat from the tubes 11 of the first section 10 and a large number of tubes are provided, a problem may arise because the steam which has been formed substantially restricts the contact between the tubes and the cooling fluid so that a sufficient dissipation of heat is not effected. This is avoided in that, as is shown in Figure 5, rooflike guide walls 17 are provided in the first cooling space 12 and in different regions guide the steam into a central region 18 the steam which has been formed. That central region 18 flares in wedge shape upwardly to the steam outlet 14 and does not contain tubes 11. Broken lines 18a and 18b indicate the boundaries of the central region 18. In that case the cooling water which has been supplied through line 13 can freely rise along the inside surface of the housing 7 in the directions indicated by arrows 13a and 13b and can flow in partial streams through the channels defined by the guide plates 17 in order to contact each of the tubes 11 as effectively as possible. At the same time, the steam formed on the outside surface of each tube 11 can flow along the undersurface of the next upper guide wall 17 into the central region 18 without a disturbing flow past other tubes 11. Three narrow tubes 11 - 217~17 of the first section open into each of the wider tubes 21 of the second section, which are indicated by broken circular lines, see also Figures 1 and 4.
Figure 6 shows a heat exchanger, which is provided with a by-pass line 35, which extend continuously from the combustion chamber 2 to the collecting chamber 28. The rate at which the gas mixture flows through line 35 can be adjusted by a control valve, which is not shown in the drawing. It is thus possible to control the temperature of the gas mixture which is processed further after it has been treated in the heat exchanger. The remaining reference characters have the meanings explained hereinbefore.
In the heat exchanger shown in Figure 7 the two sections 10 and 20 may be disposed one over the other or one beside the other. A wall 37 which is permeable to gas and liquid extends between the cooling chambers 12 and 24. The gas-vapor mixture coming from the narrow tubes 11 flows into the intermediate chamber 38 and from the latter through the wide tubes 21 of the second section 20. If the second section is disposed under the first section, any condensate which has been formed will drain through a line 29. The lines for supplying the cooling fluid have been omitted in Figure 7.
~,XaM~;~E
In an arrangement as shown in Figures 1 and 5 but having no guide walls 17, the heat exchanger in its first section 10 comprises 279 tubes made of steel and having the dimensions stated in Column A.
A B
Length 1.6 m 6.4 m Outside diameter 20 mm 52.5 mm Wall thickness 1.5 mm 3.9 mm The dimensions of the 93 steel tubes of the second section are . ~
stated above in column B. Water is used as a cooling fluid and æaturated steam at 15 bare is produced.
The combustion chamber 2 of a Claus process plant is supplied with a gas as defined in column C of the flowing Table and with air at a rate of 4900 sm3/h ~sm3 = standard cubic metre) and technically pure oxygen at a rate of 644 sm3/h:
C D E F
Rate ~sm3/h) 3560 7930 7460 6950 H2S (vol-%) 77.1 5.2 8.8 7.3 H2O (vol-%) 12.3 32.5 33.9 38.6 NH3 (vol-%) 5.6 1.1 - ~
CO (vol.%) 4.5 - - -S2 (vol.%) _ 4.0 4.6 3.8 H2 (vol-%) ~ 7.2 4.9 5.2 C2 (vol-%) 0 5 1.4 COS (vol.%) - 0.03 <0.01 <0.01 Temperature (C) 40 1416 675 353 The maximum temperature in the combustion chamber is 1416C.
A gas mixture which is at that temperature and composed as stated in column D of the above Table flows through the 279 tubes of the first section. The N content of the mixture and traces of other gases are not taken into account in the Table.
During a residence time of 24 milliseconds in the tubes 11 the gas mixture is cooled to a temperature of 675C. At that temperatures and with the composition stated in column E of the above Table the gas mixture enters the second section 21.
The gas mixture which has been cooled to 353C and has the composition stated in column F of the above Table leaves the second section 21 of the heat exchanger. Liquid elementary sulfur is simultaneously withdrawn at a rate of 2040 kg/h.
The data stated in columnæ D and E have been calculated.
Such a process and the associated apparatus are known from EP-B-0 455 285. But in that case it is not desired to cool as rapidly as possible the combustion gas that has been produced in the combustion chamber for the Claus process.
In U.S. Patent 4,481,181 it is proposed that a gas mixture which has been produced by a combustion and contains hydrogen and elementary sulfur is cooled so rapidly by an admixing of cold gas that the sulfur can no longer combine or can combine only in part with the hydrogen to form H2S. For that purpose it is recommended to effect a sudden temperature drop from about 1100C to about 950C within less than 1 second.
It is an object of the invention that the combustion gas which is produced, e.g., in the combustion chamber of a Claus process plant, should rapidly be cooled in a succeeding indirect heat exchanger. That cooling should result in a cooled gas mixture which contains molecular hydrogen that has not combined with existing elementary sulfur to form H2S. In the process described first hereinbefore this is accomplished in accordance with the invention in that the combustion gas coming from the combustion chamber is first conducted in the first section of the indirect heat exchanger through numerous ~ 2176617 tubes which have a small diameter d from 5 to 50 mm and is thus cooled in the tubes of the first section to a temperature not in excess of 800C within a residence time not in excess of 0.05 second and the combustion gas coming from the narrow tubes is conducted in a second section of the indirect heat exchanger in tubes having a diameter D which is at least 2d.
In the process in accordance with the invention a single heat exchanger is preferably used, which is divided into two sections so that a most intense cooling can be effected in the first section. This permits the use of an inexpensive apparatus. Besides, the cooling conditions in the first section can be controlled substantially independently of the conditions in the second section.
In the first section of the heat exchanger the gas mixture is cooled to such a degree that the hydrogen can no longer combine with the elementary sulfur to form H2S. But a formation of condensate is avoided because it might partly clog the narrow tubes. Only in the second section, in which the tubes are much larger in diameter, is it permissible to cool to such a degree that condensate and particularly liquid sulfur is formed. It will be understood that the tubes of a section need not be perfectly uniform in diameter.
Water is usually employed as a cooling fluid in both sections of the heat exchanger and steam is produced, which in most cases is under a pressure in the range from 5 to 30 bars. On principle, other cooling fluids, such as air, may be used in the process in accordance with the invention. To still more effectively suppress the recombination of H2 and elementary sulfur to form H2S in the combustion gas being cooled, it is recommendable to cool in the tubes of the first section of the heat exchanger to a temperature not in excess of 750C within a residence time of the gas not in excess of 0.03 second. A cooling to a temperature in the range from 500 to 700C is preferably effected within that residence time.
The invention also provides a combustion chamber for a partial combustion of an H2S-containing gas at maximum ` 2176~17 .~
temperatures in the range from about 1000 to 1800C to produce a combustion gas which contains S02, H2S, H2, H2O, and elementary sulfur. An indirect heat exchanger is directly connected to the combustion chamber and comprises numerous tubes, which are flown through by the combustion gas. The heat exchanger comprises a first section and a second section, which communicates with the first section. The tubes of the first section have a small diameter d from 5 to 50 mm, and the tubes of the second section have a larger diameter D, which lo is at least 2d. The outlet ends of the tubes of the first section are disposed in the inlet region of the tubes of the - second section, and each section is provided with at least one æupply line for cooling fluid.
In the process in accordance with the invention it is possible to withdraw from the second section of the heat exchanger a gas mixture which on a dry basis contains 2 to 30%
by volume free hydrogen. In a Claus process plant that hydrogen is useful mainly for hydrogenating, and the Claus process plant is relieved from a part of the H2S which is to be reacted. This results in a considerable saving of operating costs of a Claus process plant such as is known from EP-B-0 455 285.
Further features of the process and of the apparatus will be explained with reference to the drawing, in which Figure 1 is a schematic longitudinal sectional view showing a combustion chamber and a heat e~ch~nger connected thereto, Figure 2 is a longitudinal sectional view showing the inlet portion of a tube of the first section of the heat exchanger, Figure 3 is a longitudinal sectional view showing a modified arrangement in which a plurality of tubes of the first section open into a tube of the second section of the heat exchanger, Figure 4 is an enlarged sectional view taken on line IV-IV in Figure 3, Figure 5 is an enlarged sectional view taken on line V-V in Figure 1, Figure 6 shows a heat exchanger provided with a by-pass line, and Figure 7 shows a further modification of a heat exchanger.
In accordance with Figure 1, a burner 1 of a combustion chamber 2 is supplied through line 3 with an H2S-containing gas and through line 4 with an oxygen-containing gas, such as air, oxygen-enriched air, or technically pure oxygen. In practice, a plurality of burners may be associated with a combustion chamber. The combustion space 5 in the combustion chamber 2 is defined by refractory walls because maximum combustion temperatures from about 1000 to 1800C and usually of at least 1200C will be adjusted.
Owing to the high temperatures and the simultaneous hypo-stoichiometric supply of oxygen, the combustion gas formed in the combustion space 5 contains SO2, H2O, and residual H2S and, as a result of a thermal cracking, also H2 and elementary sulfur. By a rapid cooling in the succeeding heat exchanger 6 it is ensured that the hydrogen content is not entirely eliminated by a recombination with sulfur. For that purpose the hot gases must rapidly be cooled to a temperature not in excess of 800C. That rapid cooling is effected in a first section 10 of the heat exchanger 6 in numerous narrow tubes 11, which are disposed in a first cooling space 12. A cooling fluid, particularly water, is supplied to the first cooling space 12 through line 13. Steam which has been formed is discharged through line 14. The outlet ends of the tubes 11 are held by a first tube plate 15.
Figure 2 shows the inlet end of a single tube 11, which receives in the direction indicated by the arrow 8 the hot combustion gas coming from the combustion chamber 5. A
ceramic sleeve 9 is provided for protection from the high temperatures because experience has shown that the cooling liquid which surrounds the tube 11 cannot sufficiently 217~617 effectively be cooled in that inlet region. The refractory lining defining the combustion space 5 is designated 5a.
A æecond section 20 of the heat exchanger 6 comprises a smaller number of gas-conducting tubes 21. Two or more tubes 11 of the first section are associated with each tube 21 of the second æection 20. The ratio of the diameter d of the tube 11 to the diameter D of the tubes 21 is in most cases in the range from 1:2 to 1:5. The tubes 21 of the second section extend between a second tube plate 22 and a lo third tube plate 23. A second cooling space 24 is supplied through line 25 with a cooling fluid, such as water, and steam is discharged through line 26.
The two tube plates 15 and 22 are gas-tightly interconnected by a ring 30. Besides, the exchange of liquid between the first and second cooling chambers is restricted by a perforated separating disk 31 provided between the ring 30 and the housing 7 of the heat exchanger. Because the disk 31 is permeable to the steam which has been formed, the same pressure is maintained in the two cooling spaces 12 and 24.
Furthermore, the disk 31 supports the two tube plates 15 and 22 against the housing 7.
Care is taken that the gas flowing through the tubes 11 in the first section 10 of the heat exchanger 6 will be cooled to a temperature in the range from 500 to 800C within a residence time which is not in excess of 0.05 second and preferably not in excess of 0.03 second. As is shown in the simplified Figure 1 the gas which has thus been cooled flows from two tubes 11 into one larger tube 21 of the second cooling section and is cooled further therein. The gas mixture leaving the tubes 21 first flows into a collecting chamber 28, from which any condensate which has been formed is withdrawn through line 29. Such condensate may contain, e.g., elementary sulfur. The gas which in addition to SO2, H2O, and H2S contains also molecular hydrogen finally leaves the heat exchanger 6 through a discharge line 33. The gas conducted through the discharge line 33 is usually at ~ 2176617 temperatures in the range from 200 to 400C and may be subjected to a catalystic further processing in a Claus process plant.
If it is desired to omit the two tube plates 15 and 22 shown in Figure 1 it will be possible to connect two or more tubes 11 to a larger tube 21 in the manner illustrated in Figure 3. In that case the tube 21 is provided at its inlet end with a cover 21a, through which the tubes 11 tightly extend. Figure 4 is associated with Figure 3 and a sectional view taken on line IV-IV in Figure 3 shows three tubes 11 associated with one larger tube 21. For mechanical stability a plurality of tubes 21 are supported in the housing 7 of the heat exchanger close to their covers 2la on a perforate separating wall 31, which is indicated in Figure 3.
If cooling water is used to indirectly dissipate heat from the tubes 11 of the first section 10 and a large number of tubes are provided, a problem may arise because the steam which has been formed substantially restricts the contact between the tubes and the cooling fluid so that a sufficient dissipation of heat is not effected. This is avoided in that, as is shown in Figure 5, rooflike guide walls 17 are provided in the first cooling space 12 and in different regions guide the steam into a central region 18 the steam which has been formed. That central region 18 flares in wedge shape upwardly to the steam outlet 14 and does not contain tubes 11. Broken lines 18a and 18b indicate the boundaries of the central region 18. In that case the cooling water which has been supplied through line 13 can freely rise along the inside surface of the housing 7 in the directions indicated by arrows 13a and 13b and can flow in partial streams through the channels defined by the guide plates 17 in order to contact each of the tubes 11 as effectively as possible. At the same time, the steam formed on the outside surface of each tube 11 can flow along the undersurface of the next upper guide wall 17 into the central region 18 without a disturbing flow past other tubes 11. Three narrow tubes 11 - 217~17 of the first section open into each of the wider tubes 21 of the second section, which are indicated by broken circular lines, see also Figures 1 and 4.
Figure 6 shows a heat exchanger, which is provided with a by-pass line 35, which extend continuously from the combustion chamber 2 to the collecting chamber 28. The rate at which the gas mixture flows through line 35 can be adjusted by a control valve, which is not shown in the drawing. It is thus possible to control the temperature of the gas mixture which is processed further after it has been treated in the heat exchanger. The remaining reference characters have the meanings explained hereinbefore.
In the heat exchanger shown in Figure 7 the two sections 10 and 20 may be disposed one over the other or one beside the other. A wall 37 which is permeable to gas and liquid extends between the cooling chambers 12 and 24. The gas-vapor mixture coming from the narrow tubes 11 flows into the intermediate chamber 38 and from the latter through the wide tubes 21 of the second section 20. If the second section is disposed under the first section, any condensate which has been formed will drain through a line 29. The lines for supplying the cooling fluid have been omitted in Figure 7.
~,XaM~;~E
In an arrangement as shown in Figures 1 and 5 but having no guide walls 17, the heat exchanger in its first section 10 comprises 279 tubes made of steel and having the dimensions stated in Column A.
A B
Length 1.6 m 6.4 m Outside diameter 20 mm 52.5 mm Wall thickness 1.5 mm 3.9 mm The dimensions of the 93 steel tubes of the second section are . ~
stated above in column B. Water is used as a cooling fluid and æaturated steam at 15 bare is produced.
The combustion chamber 2 of a Claus process plant is supplied with a gas as defined in column C of the flowing Table and with air at a rate of 4900 sm3/h ~sm3 = standard cubic metre) and technically pure oxygen at a rate of 644 sm3/h:
C D E F
Rate ~sm3/h) 3560 7930 7460 6950 H2S (vol-%) 77.1 5.2 8.8 7.3 H2O (vol-%) 12.3 32.5 33.9 38.6 NH3 (vol-%) 5.6 1.1 - ~
CO (vol.%) 4.5 - - -S2 (vol.%) _ 4.0 4.6 3.8 H2 (vol-%) ~ 7.2 4.9 5.2 C2 (vol-%) 0 5 1.4 COS (vol.%) - 0.03 <0.01 <0.01 Temperature (C) 40 1416 675 353 The maximum temperature in the combustion chamber is 1416C.
A gas mixture which is at that temperature and composed as stated in column D of the above Table flows through the 279 tubes of the first section. The N content of the mixture and traces of other gases are not taken into account in the Table.
During a residence time of 24 milliseconds in the tubes 11 the gas mixture is cooled to a temperature of 675C. At that temperatures and with the composition stated in column E of the above Table the gas mixture enters the second section 21.
The gas mixture which has been cooled to 353C and has the composition stated in column F of the above Table leaves the second section 21 of the heat exchanger. Liquid elementary sulfur is simultaneously withdrawn at a rate of 2040 kg/h.
The data stated in columnæ D and E have been calculated.
Claims (11)
1. A process of cooling a combustion gas coming from a combustion chamber in which an H2S-containing gas is partially combusted at a maximum temperature in the range from about 1000 to 1800°C to form a combustion gas that contains SO2, H2S, H2, H2O, and elementary sulfur, wherein the combustion gas immediately after it has left the combustion chamber is conducted through an indirect heat exchanger having a cooling space supplied with a cooling fluid for dissipating the heat, characterized in that the combustion gas coming from the combustion chamber is first conducted in the first section of the indirect heat exchanger through numerous tubes which have a small diameter d from 5 to 50 mm and is thus cooled in the tubes of the first section to a temperature not in excess of 800°C within a residence time not in excess of 0.05 second and the combustion gas coming from the narrow tubes is conducted in a second section of the indirect heat exchanger in tubes having a diameter D which is at least 2d.
2. A process according to claim 1, characterized in that the combustion gas is cooled in the tubes of the first section to a temperature which is not in excess of 750°C
within a residence time of the gas which is not in excess of 0.03 second.
within a residence time of the gas which is not in excess of 0.03 second.
3. A process according to claim 1 or 2, characterized in that the first cooling space contained in the first section of the heat exchanger is provided with a first supply line for the cooling fluid and with a first vapor outlet and the second cooling space contained in the second section of the heat exchanger is provided with a second supply line for cooling fluid and with a second vapor outlet.
4. A process according to claim 1 o r 2, characterized in that the pressures in those spaces of the heat exchanger which are flown through by the cooling fluid are equal.
5. A combustion chamber for a partial combustion of an H2S-containing gas at maximum temperatures in the range from about 1000 to 1800°C to produce a combustion gas which contains SO2, H2S, H2, H2O, and elementary sulfur in combi-nation with an indirect heat exchanger, which is directly con-nected to the combustion chamber and comprises numerous tubes into which the combustion gas from the combustion chamber enters directly, in said heat exchanger heat is dissipated by a cooling fluid which is fed into a cooling space surrounding the tubes, characterized in that the heat exchanger comprises a first section connected to the combustion chamber, and a second section, which communicates with the first section, wherein the first section, wherein the tubes of the first section have a small diameter d from 5 to 50 mm, the tubes of the second section have a larger diameter D, which is at least 2d, the outlet ends of the tubes of the first section are disposed in the inlet region of the tubes of the second section, and each section is provided with at least one supply line for cooling fluid.
6. A combustion chamber according to claim 5, characterized in that the tubes of the first section extend close to their outlet ends through a first tube plate, the tubes of the second section extend close to their inlet ends through a second tube plate, and the two tube plates are interconnected.
7. A combustion chamber according to claim 5, characterized in that the tubes of the second section are provided at their inlet ends with covers and the outlet ends of at least two tubes of the first section extend through one of said covers.
8. A combustion chamber according to claim 5, 6 or 7, characterized in that the first cooling space of the first section is partly separated by a gas-permeable wall from the second cooling space, which is contained in the second section.
9. A combustion chamber according to claim 5, 6 or 7, characterized in that the cooling space of the first section contains rooflike guide walls.
10. A combustion chamber according to claim 5, characterized in that the first and second sections are arranged one over the other or one beside the other and the outlet ends of the tubes of the first section and the inlet ends of the tubes of the second section communicate with each other through an intermediate chamber.
11. A combustion chamber according to claim 5, 6, 7 or 10, characterized in that a by-pass line extends through the first and second section.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19520394.1 | 1995-06-08 | ||
| DE19520394A DE19520394A1 (en) | 1995-06-08 | 1995-06-08 | Method and device for rapidly cooling a hot gas mixture containing hydrogen and elemental sulfur |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2176617A1 true CA2176617A1 (en) | 1996-12-09 |
Family
ID=7763597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002176617A Abandoned CA2176617A1 (en) | 1995-06-08 | 1996-05-14 | Process and apparatus for a rapid cooling of a hot gas mixture which contains hydrogen and elementary sulfur |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0747318B1 (en) |
| CA (1) | CA2176617A1 (en) |
| DE (2) | DE19520394A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2392907B (en) * | 2002-09-12 | 2007-01-17 | Amer Sarssam | A process for the recovery of sulphur from gas streams containing hydrogen sulphide |
| ITUD20060217A1 (en) * | 2006-09-27 | 2008-03-28 | Gen & Marine Applic S R L | EQUIPMENT FOR INTERIOR COATING OF CONDUCTURES, AND ITS PROCEDURE |
| EP3596406A4 (en) * | 2017-03-17 | 2021-04-28 | Beckett Gas, Inc. | Heat exchanger |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2836481A (en) * | 1951-03-06 | 1958-05-27 | Shell Dev | Method and apparatus for the combustion of hydrogen sulfide and the production of sulfur |
| US2834655A (en) * | 1955-09-09 | 1958-05-13 | Parsons Co Ralph M | Production of elemental sulfur |
| GB1054128A (en) * | 1963-08-14 | |||
| FR2198888A1 (en) * | 1972-09-08 | 1974-04-05 | Bogossian Antoi E | Sulphur recovery from gas mixt - contg hydrogen sulphide and hydrocarbons |
| US4207304A (en) * | 1977-06-27 | 1980-06-10 | The Ralph M. Parsons Company | Process for sulfur production |
| US4481181A (en) * | 1982-02-08 | 1984-11-06 | Ga Technologies Inc. | Hydrogen production from in situ partial burning of H2 S |
| JPH01270502A (en) * | 1988-04-20 | 1989-10-27 | Jgc Corp | Production of hydrogen from hydrogen sulfide |
-
1995
- 1995-06-08 DE DE19520394A patent/DE19520394A1/en not_active Withdrawn
-
1996
- 1996-04-18 DE DE59601979T patent/DE59601979D1/en not_active Expired - Lifetime
- 1996-04-18 EP EP96106066A patent/EP0747318B1/en not_active Expired - Lifetime
- 1996-05-14 CA CA002176617A patent/CA2176617A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0747318B1 (en) | 1999-05-26 |
| DE59601979D1 (en) | 1999-07-01 |
| EP0747318A1 (en) | 1996-12-11 |
| DE19520394A1 (en) | 1996-12-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |