Post-treatment equipment for acid gas

Abstract

The utility model relates to the technical field of desulfurization related equipment, in particular to acid gas post-treatment equipment which comprises a thermal incineration device and an alkali washing device which are arranged in sequence, the thermal incineration device is arranged and used for conducting high-temperature treatment on tail gas generated after the desulfurization oxidation reaction, sulfide contained in the tail gas is further combusted and oxidized, the purification effect of acid gas is improved, and the environmental protection requirement is better met; and then the tail gas passing through the thermal incineration workshop section is introduced into an alkali washing device, sulfur dioxide in the tail gas is absorbed through alkali liquor, and the treatment precision of tail gas aftertreatment is improved. The liquid sulfur storage device is arranged at the head end of the thermal incineration device, so that liquid sulfur generated after desulfurization and oxidation treatment is conveniently collected; in the storage process of the liquid sulfur, part of H2S escapes from the liquid sulfur, and the device disclosed by the utility model can be used for further treating the escaped hydrogen sulfide, so that the treatment effect of the whole acid gas is better, and sulfur-containing harmful substances are more thoroughly purified.

Description

Technical Field

[0001] The utility model relates to the technical field of desulfurization related equipment, in particular to post-processing equipment for acidic gas. Background Art

[0002] Acidic gases such as hydrogen sulfide are produced during the production process in the chemical industry such as petrochemicals, coal chemicals, natural gas, and sulfuric acid plants. These acidic gases are generally treated by a desulfurization process to convert H2S into elemental sulfur as much as possible. Desulfurization equipment is a device used to treat these acidic gases containing harmful sulfur-containing substances. The commonly used desulfurization process is to use an oxidation method to convert harmful sulfur-containing substances in acidic gases into elemental sulfur. During the acid gas desulfurization process, the SO2 concentration in the tail gas after treatment is a continuous monitoring item and the monitoring concentration requirements are becoming more and more stringent. In the commonly used desulfurization equipment, there is still hydrogen sulfide or harmful sulfur-containing substances in the tail gas after the oxidation reaction. The purification effect is not ideal, and it is difficult to achieve zero exhaust gas emissions. Therefore, post-treatment equipment is required to further treat the tail gas after desulfurization treatment. Utility Model Content

[0003] The utility model aims to provide an acid gas post-processing device, which is arranged at the end of the desulfurization oxidation reaction device to further process the hydrogen sulfide or sulfur-containing harmful substances that may remain in the tail gas after the desulfurization oxidation reaction, which is more environmentally friendly.

[0004] In order to solve the above technical problems, the technical solution provided by the utility model is as follows: a post-processing device for acid gas is provided, comprising a thermal incineration device and an alkali washing device arranged in sequence;

[0005] The thermal incineration device comprises an incinerator and a main burner of the incinerator, wherein the main burner of the incinerator is arranged on the incinerator, an exhaust gas pipeline and a first combustion-supporting gas pipeline are connected to the incinerator, and the main burner of the incinerator is connected to the fuel gas pipeline and the second combustion-supporting gas pipeline;

[0006] The alkali washing device comprises a reverse spray chamber and an alkali washing tower. The reverse spray chamber is provided with a multi-stage reverse nozzle. The head end of the reverse spray chamber is connected with the end of the incinerator through a pipeline, and the end is connected with the inside of the alkali washing tower. The alkali washing tower is provided with an alkali solution spray nozzle.

[0007] On the basis of the above technical solution, a liquid sulfur storage device is further included, which is arranged at the head end of the thermal incineration device. The liquid sulfur storage device includes a liquid sulfur pool, a degassing cylinder, an evacuator and a liquid sulfur pump. The liquid sulfur pool is used to store liquid sulfur. The head end of the degassing cylinder is connected to a fan, and the tail end is inserted into the liquid sulfur in the liquid sulfur pool. The evacuator is connected to the gas outlet of the liquid sulfur pool. The liquid sulfur pump is arranged in the liquid sulfur pool for discharging liquid sulfur.

[0008] On the basis of the above technical solution, a condenser is arranged in the liquid sulfur pool, and a steam coil is also arranged at the bottom of the liquid sulfur pool.

[0009] Based on the above technical solution, the thermal incineration device also includes a waste heat boiler and is arranged at the end of the incinerator. The waste heat boiler is provided with an exhaust gas heat exchange pipeline that allows exhaust gas to pass through. The bottom end of the waste heat boiler is connected to a medium-pressure boiler water pipeline, and the top end is connected to a steam pipeline.

[0010] On the basis of the above technical solution, the combustion-supporting gas is set to be air, and blowers are provided at the head ends of the first combustion-supporting gas pipeline and the second combustion-supporting gas pipeline; and the fuel gas is natural gas.

[0011] On the basis of the above technical scheme, a first-level reverse nozzle and a second-level reverse nozzle are arranged in the reverse spray chamber, and the first-level reverse nozzle and the second-level reverse nozzle are connected with the alkali liquid tank through the first-level reverse spray pipe and the second-level reverse spray pipe respectively, and the first-level reverse spray pipe and the second-level reverse spray pipe are both provided with a circulation pump.

[0012] Based on the above technical solution, a circulating liquid cooler is provided on the first-level reverse spray pipe and is located at the end of the circulating pump.

[0013] Based on the above technical solution, a demister is arranged at the top of the interior of the alkali washing tower, and a plurality of demisters are arranged.

[0014] Based on the above technical solution, the alkali solution is a 30% sodium hydroxide solution and the pH value is maintained at 7-9.

[0015] The beneficial effects of the technical solution provided by the utility model are:

[0016] 1. The utility model provides an acid gas post-treatment device, which is arranged at the end of the desulfurization oxidation reaction device, and further treats the hydrogen sulfide or sulfur-containing harmful substances that may remain in the tail gas after the desulfurization oxidation reaction, which is more environmentally friendly; by providing a thermal incineration device for high-temperature treatment of the tail gas generated after the desulfurization oxidation reaction, the sulfide contained in the tail gas is further burned and oxidized, thereby improving the purification effect of the acid gas and meeting the environmental protection requirements; and then further, the tail gas after the thermal incineration section is introduced into the alkali washing device, and the alkali solution is used to absorb and eliminate the sulfur dioxide in the tail gas, thereby improving the processing accuracy of the tail gas post-treatment.

[0017] 2. The present application provides a liquid sulfur storage device at the head end of the thermal incineration device, so as to facilitate the collection of liquid sulfur produced after desulfurization and oxidation treatment. At the same time, part of H2S will escape from the liquid sulfur during the liquid sulfur storage process, and the escaped hydrogen sulfide can be further treated to ensure better overall acid gas treatment effect and more thorough purification of sulfur-containing harmful substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the medium-heat incineration device of the utility model;

[0019] Figure 2 It is a structural schematic diagram of the alkali washing device in the utility model;

[0020] Figure 3 It is a structural schematic diagram of the liquid sulfur storage device in the utility model; DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the description of the present invention, it should be understood that the terms "left", "right", "front", "back", "top", "bottom", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0024] like Figures 1 to 3 As shown, a post-processing device for acid gas comprises a thermal incineration device and an alkali washing device arranged in sequence;

[0025] The thermal incineration device comprises an incinerator 10 and an incinerator main burner 11, wherein the incinerator main burner 11 is arranged on the incinerator 10, and an exhaust gas pipeline 12 and a first combustion-supporting gas pipeline 13 are connected to the incinerator 10, and the incinerator main burner 11 is connected to a fuel gas pipeline 14 and a second combustion-supporting gas pipeline 15;

[0026] The alkali washing device includes a back-spray chamber 20 and an alkali washing tower 21. The back-spray chamber 20 is provided with a multi-stage back-spray nozzle. The front end of the back-spray chamber 20 is connected to the end of the incinerator 10 through a pipeline, and the end is connected to the inside of the alkali washing tower 21. The alkali washing tower 21 is provided with an alkali solution spray nozzle 22.

[0027] The utility model provides an acid gas post-treatment device, which is arranged at the end of a desulfurization oxidation reaction device, and further treats hydrogen sulfide or sulfur-containing harmful substances that may remain in the tail gas after the desulfurization oxidation reaction, which is more environmentally friendly; a thermal incineration device is provided for high-temperature treatment of the tail gas generated after the desulfurization oxidation reaction, and the sulfide contained in the tail gas is further burned and oxidized, thereby improving the purification effect of the acid gas and meeting the environmental protection requirements; and then further, the tail gas after the thermal incineration section is introduced into an alkali washing device, and an alkali solution is used to absorb and eliminate sulfur dioxide in the tail gas, thereby improving the treatment accuracy of the tail gas post-treatment.

[0028] Specifically, the acidic gas tail gas treated in the previous stage, such as the tail gas from the selective oxidation stage or the exhaust gas from the liquid sulfur pool, contains residual H2S and other sulfides and cannot be directly discharged into the atmosphere, that is, it is introduced into the incinerator 10 through the tail gas pipeline 12, and the fuel gas is introduced into the main burner 11 of the incinerator through the fuel gas pipeline 14 and the combustion-supporting gas is introduced through the second combustion-supporting gas pipeline 15. After the mixture is burned, hot flue gas is generated. The hot flue gas enters the incinerator 10 and is incinerated together with the tail gas at 750-800°C. At the same time, an excess amount of combustion-supporting gas, i.e., air, is introduced into the incinerator 10 through the first combustion-supporting gas pipeline 13 to convert the residual hydrogen sulfide and sulfide in the tail gas into sulfur dioxide. Then the tail gas containing sulfur dioxide enters the reverse spray chamber 20, and the alkaline solution sprayed from the multi-stage reverse nozzle inside the chamber contacts the tail gas in reverse order to absorb the sulfur dioxide in the tail gas. The tail gas after absorption then enters the alkali washing tower 21, and is further absorbed by the alkali solution sprayed from the alkali solution spray nozzle 22 in the alkali washing tower 4, so that the sulfur dioxide in the tail gas is absorbed to the maximum extent, completing the post-treatment process and achieving a better tail gas post-treatment effect.

[0029] Among them, the main reactions occurring in the thermal incineration device are as follows: H2S+3 / 2O2→SO2+H2O; 1 / xS x +O2→SO2; COS+3 / 2O2→SO2+CO2; CS2+3O2→CO2+2SO2; At the same time, other combustible substances such as H2 and CO are also oxidized into water and CO2 respectively: H2+1 / 2O2→H2O; CO+1 / 2O2→CO2. Sodium hydroxide solution is used as the alkaline washing solution in the alkali washing device, which can react quickly with SO2 in the tail gas; under the action of excessive sodium hydroxide, most of the SO2 in the tail gas is converted into sulfite; the main reactions in the back spray chamber and the alkali washing tower are: 2NaOH+SO2→Na2SO3+H2O+reaction heat; Na2SO3+SO2+H2O→2NaHSO3.

[0030] On the basis of the above technical solution, a liquid sulfur storage device is further included, which is arranged at the head end of the thermal incineration device. The liquid sulfur storage device includes a liquid sulfur pool 30, a degassing cylinder 31, an evacuator 32 and a liquid sulfur pump 33. The liquid sulfur pool 30 is used to store liquid sulfur. The head end of the degassing cylinder 31 is connected to a fan 34, and the tail end is inserted into the liquid sulfur in the liquid sulfur pool 30. The evacuator 32 is connected to the gas outlet 35 of the liquid sulfur pool 30. The liquid sulfur pump 33 is arranged in the liquid sulfur pool 30 for discharging liquid sulfur.

[0031] In this embodiment, a liquid sulfur storage device is provided at the head end of the thermal incineration device to facilitate the collection of liquid sulfur produced after desulfurization and oxidation treatment. At the same time, part of H2S will escape from the liquid sulfur during the storage process of liquid sulfur, and the escaped hydrogen sulfide can be further treated to ensure better overall acid gas treatment effect and more thorough purification of sulfur-containing harmful substances. Specifically, the liquid sulfur produced after the desulfurization and oxidation process is stored in an underground liquid sulfur pool, and the liquid sulfur pool can be set with corresponding storage capacity according to actual working conditions to improve its applicability; when the liquid sulfur is stored in the liquid sulfur pool 30, the residual hydrogen sulfide escapes from the liquid sulfur, and a fan 34 is used to blow air into the liquid sulfur through the degassing cylinder 31 to assist in the discharge of harmful gases, and at the same time, the evacuator 32 works to extract the escaped and discharged hydrogen sulfide and air into the incinerator 10 for incineration, and the hydrogen sulfide in the tail gas is treated more thoroughly; finally, the liquid sulfur in the liquid sulfur pool 30 is discharged through the liquid sulfur pump 33.

[0032] On the basis of the above technical solution, a condenser 301 is provided in the liquid sulfur pool 30 , and a steam coil 302 is also provided at the bottom of the liquid sulfur pool 30 .

[0033] Preferably, by providing a condenser 301 in the liquid sulfur pool 30, the liquid sulfur entering the liquid sulfur pool 30 can be cooled when necessary to facilitate discharge; at the same time, by installing a steam coil 302 at the bottom of the liquid flow pool 30, it is enabled when the temperature of the liquid sulfur pool is lower than 130°C to avoid the liquid sulfur solidifying at a temperature lower than 120°C; that is, the condenser 301 or the steam coil 302 is turned on according to different working conditions, which is more convenient to use and has better applicability.

[0034] Based on the above technical solution, the thermal incineration device also includes a waste heat boiler 40 and is arranged at the end of the incinerator 10. The waste heat boiler 40 is provided with an exhaust gas heat exchange pipeline that allows exhaust gas to pass through. The bottom end of the waste heat boiler 40 is connected to a medium-pressure boiler water pipeline 41, and the top end is connected to a steam pipeline 42.

[0035] By arranging a waste heat boiler 40 at the end of the incinerator 10, the heat generated during the incineration of the tail gas can be recycled and utilized, so as to make full use of energy, improve energy utilization rate, and be more energy-saving and environmentally friendly; specifically, the tail gas after heat treatment in the incinerator 10 enters the tail gas heat exchange pipeline in the waste heat boiler 40, and the medium-pressure boiler water is introduced into the waste heat boiler 40 through the medium-pressure boiler water pipeline 41, that is, when the hot tail gas passes through, the medium-pressure boiler water absorbs the heat in the tail gas to form steam, and the steam flows out from the steam pipeline 42 connected to the top of the waste heat boiler 40, which is convenient for subsequent reuse. More preferably, the tail gas flows out of the tail gas heat exchange pipeline and enters the tail gas heat exchanger 43 to further recover the heat in the tail gas for reuse, and then flows out to the next alkali washing section.

[0036] Based on the above technical solution, the combustion-supporting gas is set to be air, and the first ends of the first combustion-supporting gas pipeline 13 and the second combustion-supporting gas pipeline 15 are provided with blowers 50; and the fuel gas is natural gas.

[0037] Specifically, the temperature of the incinerator 10 is controlled by controlling the flow rate of fuel gas, and the incinerator combustion-supporting gas is provided by a blower 50; preferably, the incinerator combustion-supporting gas in this embodiment is divided into three parts: primary air, i.e., the second combustion-supporting gas, is used for sub-chemical equivalent combustion of the fuel gas; secondary air, i.e., the first combustion-supporting gas, is used for over-chemical equivalent combustion of the fuel gas; and also includes secondary air for adjusting the furnace temperature of the incinerator.

[0038] On the basis of the above technical scheme, a primary reverse nozzle 201 and a secondary reverse nozzle 202 are arranged in the reverse spray chamber 20. The primary reverse nozzle 201 and the secondary reverse nozzle 202 are connected to the alkali liquid tank 60 through a primary reverse spray pipe 203 and a secondary reverse spray pipe 204 respectively. A circulation pump 205 is arranged on the primary reverse spray pipe 203 and the secondary reverse spray pipe 204.

[0039] Based on the above technical solution, a circulating liquid cooler 206 is provided on the first-level reverse spray pipe 203 and is located at the end of the circulating pump 205 .

[0040] In this embodiment, by providing a multi-stage reverse nozzle in the reverse spray chamber 20, the tail gas can be absorbed in multiple stages, the absorption effect of sulfur-containing substances is better, the post-treatment effect is improved, and serious pollution to the environment is avoided. Specifically, the tail gas generated by the thermal incineration section enters the reverse spray chamber 20, and a circulating liquid cooler 206 is provided at the outlet of the circulating pump on the first-level reverse spray pipe 203 to cool the circulating alkali solution to below 45°C, and the hot flue gas is adiabatically quenched by the cooled alkali solution, and the hot flue gas is cooled to 56°C, and is sprayed out through the first-level reverse nozzle 201 to absorb SO2 in the tail gas; then the alkali solution circulating in the circulating pump on the second-level reverse spray pipe 204 is sprayed out through the second-level reverse nozzle 202 to further absorb SO2 in the tail gas; then the treated tail gas enters the alkali washing tower 21; more preferably, the alkali solution spray nozzle 22 in the alkali washing tower 21 is also supplied through one of the branches of the second-level reverse spray pipe 204.

[0041] On the basis of the above technical solution, a demister 23 is arranged at the top of the alkali washing tower 21 , and a plurality of demisters 23 are arranged.

[0042] Before the tail gas after alkali washing in the alkali washing tower 21 is discharged into the air, the sodium sulfite / sodium sulfate droplets entrained in the gas are separated from the gas by a two-stage demister 23, and the gas is then discharged outdoors, and the exhaust gas emission is more environmentally friendly. More preferably, during long-term use, the demister 23 in the alkali washing tower 21 needs to be regularly flushed with desalted water to maintain its gas-liquid separation effect.

[0043] More preferably, air is sprayed inwardly by a main fan 70 at the bottom of the alkali washing tower 21 to generate appropriate bubbles, and oxygen reacts with sodium sulfite and sodium bisulfite in the circulating liquid to generate sodium sulfate. The main reactions involved are: 2NaHSO3+O2→Na2SO4+H2O, 2Na2SO3+O2→2Na2SO4, and the solution is discharged after the density exceeds the set value.

[0044] On the basis of the above technical solution, the alkali solution is a 30% sodium hydroxide solution and the pH value is maintained at 7-9. More preferably, the pH value of the alkali solution is maintained at 7.2. Specifically, an alkali solution metering pump can be used to replenish 30% of the alkali solution in real time to the alkali washing tower so that the pH value of the alkali solution remains stable during the tail gas treatment process. The pH value of 7.2 is the best value for absorbing the most sulfur dioxide without absorbing a large amount of carbon dioxide. More preferably, the pH is controlled by a pH meter, and the liquid level is controlled by a liquid level meter. The density, pH, and liquid level meter coordinately control the balance of the liquid level, density, and pH in the alkali washing tower to ensure the absorption effect of sulfur dioxide.

[0045] There may be a large amount of carbon dioxide in the exhaust gas. If the pH value of the solution is too high, it will react with NaOH to generate Na2CO3, which will consume a large amount of sodium hydroxide. If the pH value of the solution is too low, it will not be enough to remove SO2 in the exhaust gas, so the pH value of the alkali solution is controlled within the range of 7 to 9; 2NaOH+CO2→Na2CO3+H2O; different reactions of sulfur dioxide and sodium carbonate under different conditions: 2Na2CO3+SO2+H2O→2NaHCO3+Na2SO3; Na2CO3+SO2→CO2+Na2SO3; Na2CO3+2SO2+H2O→CO2+2NaHSO3.

[0046] It should be noted that the head end and the end end mentioned above are defined according to the flow direction of the medium such as liquid, gas or steam in the pipeline, which is only for the convenience of understanding and description of the present technical solution and does not constitute a limitation to the present application.

[0047] The basic principle and main features of the utility model are shown and described above. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the appended claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the utility model.

[0048] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A post-treatment device for acid gas, characterized in that: It includes a thermal incineration device and an alkali washing device which are arranged in sequence; The thermal incineration device comprises an incinerator (10) and an incinerator main burner (11); the incinerator main burner (11) is arranged on the incinerator (10); an exhaust gas pipeline (12) and a first combustion-supporting gas pipeline (13) are connected to the incinerator (10); the incinerator main burner (11) is in communication with a fuel gas pipeline (14) and a second combustion-supporting gas pipeline (15); The alkali washing device comprises a reverse spray chamber (20) and an alkali washing tower (21), wherein the reverse spray chamber (20) is provided with a multi-stage reverse nozzle, the head end of the reverse spray chamber (20) is connected to the end of the incinerator (10) through a pipeline, and the end is connected to the inside of the alkali washing tower (21), and the alkali washing tower (21) is provided with an alkali liquid spray nozzle (22).

2. The acid gas post-treatment equipment according to claim 1, characterized in that: The invention also comprises a liquid sulfur storage device arranged at the head end of the thermal incineration device, the liquid sulfur storage device comprising a liquid sulfur pool (30), a degassing cylinder (31), an evacuator (32) and a liquid sulfur pump (33), the liquid sulfur pool (30) is used to store liquid sulfur, the head end of the degassing cylinder (31) is connected to a fan (34), and the tail end is inserted into the liquid sulfur in the liquid sulfur pool (30), the evacuator (32) is connected to the gas outlet (35) of the liquid sulfur pool (30), and the liquid sulfur pump (33) is arranged in the liquid sulfur pool (30) for discharging liquid sulfur.

3. The acid gas post-treatment equipment according to claim 2, characterized in that: A condenser (301) is arranged in the liquid sulfur pool (30), and a steam coil (302) is also arranged at the bottom end of the liquid sulfur pool (30).

4. The acid gas post-treatment equipment according to claim 1, characterized in that: The thermal incineration device also includes a waste heat boiler (40) disposed at the end of the incinerator (10), wherein an exhaust gas heat exchange pipeline is disposed in the waste heat boiler (40) to allow exhaust gas to pass through, wherein the bottom end of the waste heat boiler (40) is connected to a medium-pressure boiler water pipeline (41), and the top end is connected to a steam pipeline (42).

5. The acid gas post-treatment equipment according to claim 1, characterized in that: The combustion-supporting gas is set to be air, and blowers (50) are provided at the head ends of the first combustion-supporting gas pipeline (13) and the second combustion-supporting gas pipeline (15); and the fuel gas is natural gas.

6. The acid gas post-treatment equipment according to claim 1, characterized in that: A primary reverse nozzle (201) and a secondary reverse nozzle (202) are arranged in the reverse spray chamber (20); the primary reverse nozzle (201) and the secondary reverse nozzle (202) are connected to the alkali liquid tank (60) through a primary reverse spray pipe (203) and a secondary reverse spray pipe (204), respectively; and a circulation pump (205) is arranged on the primary reverse spray pipe (203) and the secondary reverse spray pipe (204).

7. The acid gas post-treatment equipment according to claim 6, characterized in that: A circulating liquid cooler (206) is provided on the first-level reverse spray pipe (203) and is located at the end of the circulating pump (205).

8. The acid gas post-treatment equipment according to claim 1, characterized in that: A demister (23) is provided at the top of the interior of the alkali washing tower (21), and a plurality of demisters (23) are provided.

9. The acid gas post-treatment equipment according to claim 1, characterized in that: The alkali solution is 30% sodium hydroxide solution and the pH value is maintained at 7-9.

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