Device and process for the production of sulfuric acid from wet acid gas

Abstract

The application provides a device and a process for preparing sulfuric acid from wet acid gas, which comprises a combustion furnace, a first waste heat boiler, a sulfur dioxide converter, a second waste heat boiler, a condenser and an activated carbon reactor connected in sequence through pipelines, the sulfur dioxide converter comprises four catalyst beds arranged from top to bottom, two air supplement valves and two interlayer heat exchangers are arranged on the sulfur dioxide converter, and a reflux pipe is communicated between the activated carbon reactor and the condenser. The process can handle various working conditions of raw gas with different concentrations, the oxygen concentration in the catalyst bed can be adjusted according to the change of the concentration of the raw gas, the catalyst bed can be cooled in an emergency when over-temperature phenomenon occurs in the catalyst bed, the activated carbon reactor at the tail end is used to adsorb and convert sulfur dioxide to obtain dilute sulfuric acid, the dilute sulfuric acid is refluxed to the condenser to spray sulfur trioxide, high-concentration sulfuric acid is obtained, no waste water is generated in the whole process, and the tail gas can be discharged up to the standard.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sulfuric acid preparation, in particular to a device and process for preparing sulfuric acid from wet acid gas. BACKGROUND

[0002] Since the 21st century, China has built dozens of WSA sulfuric acid production devices relying on the WSA patent technology of Denmark's Topsoe Company, which has made the wet process for preparing sulfuric acid develop rapidly in China. These WSA sulfuric acid production devices are mainly used as environmental protection devices for treating acid gas in the desulfurization unit, and generally have a small scale, are used to directly produce acid liquid from sulfur-containing acid gas in production, and are mainly distributed in the oil refining, non-ferrous metal smelting, chemical fertilizer, viscose fiber, coal coking, coal chemical industry and other industries, are used for treating low-sulfur gas, obtain commercial-grade concentrated sulfuric acid, and the tail gas meets the emission standard. The process catalytically converts sulfur dioxide into sulfur trioxide in the presence of water vapor, and directly condenses into sulfuric acid without washing and drying, and has the advantages of simple process, high sulfur recovery rate, high energy efficiency, no waste water generation, large operation flexibility, low operation cost, no environmental pollution, etc.

[0003] The one-conversion-one-cooling process in the existing traditional wet acid gas acid-making device considers the problem of bed pressure drop, and the number of catalyst bed layers in the SO2 converter is at most three, and the total SO2 conversion rate can be improved by using a two-conversion-two-cooling process, but this will increase the equipment cost. In addition, whether it is a one-conversion-one-cooling mode or a two-conversion-two-cooling mode, only one kind of raw material gas component working condition can be adapted at the initial design, or the raw material gas component can only have slight changes, so that if the upstream working condition changes greatly, for example, after the upstream coal changes from low-sulfur coal to high-sulfur coal, the concentration at the inlet of the SO2 converter increases greatly, thereby causing the total SO2 conversion rate to fluctuate greatly. SUMMARY

[0004] The present application aims to provide a device and process for preparing sulfuric acid from wet acid gas.

[0005] To achieve the above-mentioned purpose, the present application proposes the following technical solutions:

[0006] A device for preparing sulfuric acid from wet acid gas, comprising a incinerator, a first waste heat boiler, a sulfur dioxide converter, a second waste heat boiler, a condenser and an activated carbon reactor connected in sequence by pipelines;

[0007] The sulfur dioxide converter comprises a first catalyst bed, a second catalyst bed, a third catalyst bed and a fourth catalyst bed arranged in sequence from top to bottom, the inlet and outlet of the second catalyst bed are respectively provided with a first air supplement valve and a second air supplement valve for supplementing oxygen and emergency cooling, and an interlayer heat exchanger is arranged between the second catalyst bed and the third catalyst bed and between the third catalyst bed and the fourth catalyst bed;

[0008] The condenser is connected with the first air supplement valve through a first branch pipe;

[0009] The activated carbon reactor is internally provided with an activated carbon catalyst bed and a first spraying device for spraying desalted water, and a reflux pipe is communicated between the activated carbon reactor and the condenser, and the reflux pipe is used for refluxing dilute sulfuric acid in the activated carbon reactor to the condenser to spray sulfur trioxide in the condenser.

[0010] As a preferred technical scheme of the present application, the condenser comprises a third shell, a third heat exchange pipe and a second spraying device;

[0011] The inner cavity of the third shell is respectively communicated with the second waste heat boiler and the activated carbon reactor through pipelines;

[0012] The third heat exchange pipe is arranged in the inner cavity of the third shell, and the outlet of the third heat exchange pipe is connected with the first air supplement valve through the first branch pipe;

[0013] The second spraying device is arranged at the top end of the inner cavity of the third shell, and the inlet of the second spraying device is connected with the outlet of the reflux pipe.

[0014] As a preferred technical scheme of the present application, the incinerator is provided with an air inlet pipe and a fuel supplement pipe, and the air inlet pipe is provided with a second branch pipe between the outlet of the third heat exchange pipe;

[0015] The inlet and outlet of the second catalyst bed are respectively provided with a first horizontal porous air column and a second horizontal porous air column;

[0016] The first air supplement valve is used for introducing hot air from the third heat exchange pipe into the first horizontal porous air column, and the hot air is mixed with process gas from the first catalyst bed and then enters the second catalyst bed, so as to supplement oxygen and perform emergency cooling for the second catalyst bed;

[0017] The second air supplement valve is used for introducing cold air into the second horizontal porous air column, and the cold air is mixed with process gas from the second catalyst bed and then enters the third catalyst bed, so as to supplement oxygen and perform emergency cooling for the third catalyst bed;

[0018] Air filters are arranged at air inlets of the first and second air supplement valves.

[0019] As a preferred technical solution of the present application, the first waste heat boiler comprises a first shell, first heat exchange pipes and a first steam drum, the first heat exchange pipes are arranged in the inner cavity of the first shell, the inlets and outlets of the first heat exchange pipes are connected with the incinerator and the sulfur dioxide converter respectively, and the first steam drum is in communication with the inner cavity of the first shell.

[0020] The second waste heat boiler comprises a second shell, second heat exchange pipes and a second steam drum, the second heat exchange pipes are arranged in the inner cavity of the second shell, the inlets and outlets of the second heat exchange pipes are connected with the sulfur dioxide converter and the condenser respectively, and the second steam drum is in communication with the inner cavity of the second shell.

[0021] The inlets of the interlayer heat exchangers are connected with the outlets of the first steam drum and / or the second steam drum, so that the water vapor generated by the first steam drum and / or the second steam drum enters the interlayer heat exchangers to exchange heat with the first process gas and the second process gas.

[0022] As a preferred technical solution of the present application, the first catalyst bed is filled with platinum-based catalyst, and the height of the first catalyst bed is 500-1000 mm.

[0023] The platinum-based catalyst has an outer size of 150*150*600 mm or 150*150*300 mm 60-hole honeycomb catalyst, and the carrier used by the platinum-based catalyst is titanium dioxide.

[0024] The second catalyst bed, the third catalyst bed and the fourth catalyst bed are all filled with vanadium-based catalyst, and the heights of the second catalyst bed, the third catalyst bed and the fourth catalyst bed are 500-600 mm.

[0025] As a preferred technical solution of the present application, the active carbon of the active carbon catalyst bed is filled in an amount of 80-100 m 3 .

[0026] As a preferred technical solution of the present application, the condenser is provided with an electrostatic precipitator at the top end, and the electrostatic precipitator is used for removing acid mist.

[0027] The present application provides a process for preparing sulfuric acid from wet acid gas, which uses the device for preparing sulfuric acid from wet acid gas as described above to prepare sulfuric acid, and the process comprises the following steps:

[0028] (1) the acid gas containing hydrogen sulfide and air enter the incinerator to burn, to generate the first process gas rich in sulfur dioxide;

[0029] (2) the first process gas enters the first waste heat boiler for heat exchange and cooling, and then enters the sulfur dioxide converter;

[0030] (3) the sulfur dioxide in the first process gas is converted into sulfur trioxide in the sulfur dioxide converter to obtain a second process gas rich in sulfur trioxide; the flow of hot air entering the second catalyst bed is adjusted by the first air supplement valve according to the concentration of sulfur dioxide in the first process gas, and the hot air is used for supplementing oxygen and removing heat; when over-temperature phenomenon occurs in the third catalyst bed, cold air is introduced into the third catalyst bed through the second air supplement valve, and the cold air is used for emergency cooling;

[0031] (4) the second process gas enters the second waste heat boiler for heat exchange and cooling, and then enters the condenser for heat exchange with air to condense, so that the sulfur trioxide in the second process gas is condensed and forms sulfuric acid under the spraying of dilute sulfuric acid, and the third process gas obtained at the same time enters the activated carbon reactor; the hot air heated by the condenser enters the second catalyst bed through the first branch pipe and the first air supplement valve;

[0032] (5) the sulfur dioxide in the third process gas is converted into sulfur trioxide under the catalytic oxidation of the activated carbon catalyst bed, the generated sulfur trioxide contacts with desalted water to obtain dilute sulfuric acid, and the sulfur dioxide in the remaining tail gas is discharged up to the standard;

[0033] (6) the dilute sulfuric acid generated in the activated carbon reactor enters the condenser through the reflux pipe to spray the sulfur trioxide inside the condenser, so that the sulfur trioxide is converted into sulfuric acid, and no waste water is generated.

[0034] As a preferred technical solution of the present application, a part of the hot air heated by the condenser is mixed with the acid gas containing hydrogen sulfide and then enters the incinerator;

[0035] The water vapor generated by the first waste heat boiler and / or the second waste heat boiler enters the interlayer heat exchanger.

[0036] As a preferred technical solution of the present application, when the acid gas containing hydrogen sulfide is burned in the incinerator, fuel is supplemented to the incinerator through the fuel supplement pipe, and the fuel is any one or more than one of natural gas and hydrocarbon compounds.

[0037] The technical solution of the present application provides a device and process for preparing sulfuric acid from wet acid gas, which has the following beneficial effects compared with the prior art:

[0038] (1) By setting four catalyst beds and two interlayer heat exchangers between two adjacent catalyst beds in the sulfur dioxide converter, and setting a makeup air valve between two adjacent catalyst beds without an interlayer heat exchanger, the makeup air valve can replace the interlayer heat exchanger. In the case of saving one interlayer heat exchanger, the sulfur dioxide converter can achieve the effect of one-stage conversion and one-stage condensation, thus saving equipment costs.

[0039] (2) The sulfuric acid preparation device and process can handle various working conditions of raw gas with different concentrations. The flow rate of hot air introduced by the first air supply valve can be adjusted according to the change of raw gas concentration, thereby dynamically adjusting the oxygen concentration entering the second catalyst bed, so that the oxygen concentration and the sulfur dioxide concentration in the raw gas are kept in the most suitable conversion ratio, and the conversion rate of sulfur dioxide is always kept at a high level.

[0040] (3) In addition, when the third catalyst bed overheats during the catalytic oxidation of sulfur dioxide, an appropriate amount of cold air is introduced through the second air supply valve to cool the third catalyst bed in an emergency, so as to prevent the third catalyst bed from being deactivated due to the high temperature and maximize the conversion rate of sulfur dioxide.

[0041] (4) An activated carbon reactor is installed at the end of the device so that the sulfur dioxide in the non-condensable gas discharged from the condenser is catalytically oxidized into sulfur trioxide, and then the sulfuric acid is formed by spraying with demineralized water. Then the sulfuric acid is returned to the condenser to spray sulfur trioxide to obtain sulfuric acid with a higher concentration. No wastewater is generated in the whole process, and the tail gas from the activated carbon reactor meets the emission standards, that is, the sulfur dioxide concentration is extremely low and meets the emission standards.

[0042] The process proposed in this invention adjusts the oxygen concentration of the catalyst bed according to the raw gas concentration, urgently cools the overheated catalyst bed, and uses an activated carbon reactor to treat the small amount of sulfur dioxide emitted after condensation in the condenser, converting it into sulfuric acid. These multiple measures ensure that the total conversion rate of sulfur dioxide is greater than or equal to 99.2% under various operating conditions.

[0043] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0044] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0045] The drawings are not drawn to scale. In the drawings, like or similar components of each figure can be denoted with the same reference number. For the sake of clarity, not every component can be labeled in every figure. Embodiments of various aspects of the present application will now be described, by way of example only, with reference to the drawings in which:

[0046] Figure 1 is a process flow diagram of the present application;

[0047] Figure 2 is a structural diagram of a sulfur dioxide converter of the present application.

[0048] 1 - first catalyst bed 2 - second catalyst bed 3 - third catalyst bed 4 - fourth catalyst bed 5 - first air supplement valve 6 - second air supplement valve 7 - inter-bed heat exchanger DETAILED DESCRIPTION

[0049] In order to make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described below clearly and completely with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as their common meanings to those skilled in the art of the present application.

[0050] The terms "first", "second", and similar terms used herein do not necessarily indicate any order, quantity, or importance, but are used to distinguish different components. Also, unless otherwise specified, the singular forms "a", "an", and "the" or similar terms do not necessarily indicate quantity restrictions, but indicate the existence of at least one. The terms "include", "comprise", and similar terms mean that the elements or objects before the "include" or "comprise" cover the features, integers, steps, operations, elements, and / or components listed after the "include" or "comprise", and do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. The terms "up", "down", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0051] As Figure 1As shown, the embodiment of the present application provides a device for preparing sulfuric acid from wet acid gas, which comprises a combustion furnace, a first waste heat boiler, a sulfur dioxide converter, a second waste heat boiler, a condenser and an activated carbon reactor connected in sequence through pipelines.

[0052] The combustion furnace is used for burning the acid gas containing hydrogen sulfide therein to generate a first process gas rich in sulfur dioxide.

[0053] The combustion furnace is provided with an air inlet pipe for introducing the acid gas containing hydrogen sulfide and air into the combustion furnace, and a fuel supplement pipe for introducing fuel into the combustion furnace to enable the hydrogen sulfide to be fully combusted to generate sulfur dioxide. The air inlet pipe is provided with a second branch pipe in communication with the condenser, which is used for mixing the hot air heated by the condenser with the acid gas containing hydrogen sulfide to supplement air and oxygen. The hearth of the combustion furnace is connected with the first waste heat boiler through a pipeline.

[0054] The first waste heat boiler is a high-temperature waste heat boiler, which is used for heat exchange with the first process gas from the combustion furnace to reduce the temperature of the first process gas and heat the water in the first waste heat boiler to form water vapor.

[0055] The first waste heat boiler comprises a first shell, a first heat exchange pipe and a first steam pocket. The first heat exchange pipe is arranged in the inner cavity of the first shell, the inlet of the first heat exchange pipe is connected with the hearth of the combustion furnace through a pipeline, thus the first process gas from the combustion furnace directly enters the first heat exchange pipe to exchange heat with the water in the inner cavity of the first shell, and the outlet of the first heat exchange pipe is connected with the inlet of the top end of the sulfur dioxide converter through a pipeline. The inlet of the first steam pocket is in communication with the inner cavity of the first shell, and the outlet of the first steam pocket is connected with the interlayer heat exchanger. The water in the inner cavity of the first shell is heated by the high-temperature first process gas to become water vapor which enters the first steam pocket and then enters the interlayer heat exchanger through a pipeline to exchange heat.

[0056] The sulfur dioxide converter is used for converting the sulfur dioxide in the first process gas into sulfur trioxide, and is a main conversion device for sulfur dioxide. Therefore, it is crucial to control and adjust the process conditions of the sulfur dioxide converter to keep the sulfur dioxide catalytic oxidation process in a suitable reaction environment to improve the conversion rate of sulfur dioxide.

[0057] The sulfur dioxide converter is a vertical multi-stage catalytic bed layer converter, which comprises a first catalyst bed layer 1, a second catalyst bed layer 2, a third catalyst bed layer 3 and a fourth catalyst bed layer 4 arranged in sequence from top to bottom. The inlet and outlet of the second catalyst bed layer 2 are respectively provided with a first air supplement valve 5 and a second air supplement valve 6 for supplementing oxygen and emergency cooling.

[0058] The second catalyst bed and the third catalyst bed are provided with inter-bed heat exchangers, and the second catalyst bed is provided with a first transverse porous air column and a second transverse porous air column.

[0059] The air filter screen is arranged at the air inlet of the first air supplement valve and the second air supplement valve.

[0060] The first catalyst bed 1 is filled with platinum-based catalyst, and the height of the first catalyst bed 1 is 500-1000 mm.

[0061] The platinum-based catalyst has an outer size of 150*150*600 mm or 150*150*300 mm 60-hole honeycomb catalyst, and the carrier used by the platinum-based catalyst is titanium dioxide.

[0062] The second catalyst bed 2, the third catalyst bed 3 and the fourth catalyst bed 4 are all filled with vanadium-based catalyst, and the height of the second catalyst bed 2, the third catalyst bed 3 and the fourth catalyst bed 4 is 500-600 mm.

[0063] The first air supplement valve is used for feeding the hot air from the third heat exchange pipe into the first transverse porous air column, and the hot air is mixed with the process gas from the first catalyst bed to enter the second catalyst bed, so as to supplement oxygen and perform emergency cooling for the second catalyst bed. Specifically, the air inlet of the first air supplement valve 5 is connected with the third heat exchange pipe through a first branch pipe, the air outlet of the first air supplement valve 5 is connected with the first transverse porous air column, the hot air is uniformly distributed through the first transverse porous air column, and the hot air is more easily mixed with the process gas from the first catalyst bed, the first air supplement valve 5 adjusts the flow of the hot air into the second catalyst bed according to the concentration of sulfur dioxide in the raw gas, so that the concentration of oxygen and the concentration of sulfur dioxide in the raw gas maintain the most suitable conversion ratio, and the conversion rate of sulfur dioxide is always maintained at a high level.

[0064] The second air supplement valve is used for feeding the cold air into the second transverse porous air column, and the cold air is mixed with the process gas from the second catalyst bed to enter the third catalyst bed, so as to supplement oxygen and perform emergency cooling for the third catalyst bed. Specifically, the air outlet of the second air supplement valve 6 is connected with the second transverse porous air column, the cold air is uniformly distributed through the second transverse porous air column, and the cold air is more easily mixed with the process gas from the second catalyst bed, so that when the third catalyst bed is overheated in the process of catalytically oxidizing sulfur dioxide, the second air supplement valve is used to feed appropriate cold air to perform emergency cooling for the third catalyst bed, so as to avoid the deactivation of the third catalyst bed due to over-high temperature, and to maximize the conversion rate of sulfur dioxide.

[0065] The air filter screen is arranged at the air inlet of the first air supplement valve 5 and the second air supplement valve 6, and the filtered hot air is delivered into the first transverse porous air column, and the filtered cold air is delivered into the second transverse porous air column.

[0066] As shown in Figure 2 The two interlayer heat exchangers 7 of the embodiment are arranged between the second catalyst bed 2 and the third catalyst bed 3, and between the third catalyst bed 3 and the fourth catalyst bed 4, respectively; the inlet of the interlayer heat exchanger 7 is connected with the outlet of the first steam drum or the second steam drum, or the inlet of the interlayer heat exchanger is connected with the first steam drum and the second steam drum through two pipes, so that the water vapor generated by the first steam drum or the second steam drum, or the water vapor generated by the first steam drum and the second steam drum is all delivered into the interlayer heat exchanger, and is used for removing heat from the reaction process gas in the sulfur dioxide converter.

[0067] The second waste heat boiler is a medium-temperature waste heat boiler, which is used for heat exchange with the second process gas from the sulfur dioxide converter, reduces the temperature of the second process gas, and heats the water in the second waste heat boiler to form water vapor. The second process gas contains a large amount of sulfur trioxide gas and a small amount of sulfur dioxide gas.

[0068] The second waste heat boiler comprises a second shell, a second heat exchange pipe and a second steam drum. The second heat exchange pipe is arranged in the inner cavity of the second shell, the inlet of the second heat exchange pipe is connected with the outlet of the sulfur dioxide converter through a pipe, so that the second process gas from the sulfur dioxide converter directly enters the second heat exchange pipe and exchanges heat with the water in the inner cavity of the second shell, and the outlet of the second heat exchange pipe is connected with the third shell inner cavity of the condenser through a pipe; the inlet of the second steam drum is communicated with the inner cavity of the second shell, and the outlet of the second steam drum is connected with the interlayer heat exchanger, the water in the inner cavity of the second shell is heated by the second process gas to become water vapor and enters the second steam drum, and then enters the interlayer heat exchanger through a pipe to exchange heat.

[0069] The condenser is used for condensing the second process gas, reducing the temperature of the sulfur trioxide in the second process gas, and forming a sulfuric acid solution with a higher concentration under the spraying of dilute sulfuric acid.

[0070] The condenser comprises a third shell, a third heat exchange pipe, a second spraying device and an electrostatic demister. The inlet of the inner cavity of the third shell is connected with the outlet of the second heat exchange pipe through a pipeline, and the outlet of the inner cavity of the third shell is connected with the inlet of the activated carbon reactor through a pipeline; the third heat exchange pipe is arranged in the inner cavity of the third shell, the inlet of the third heat exchange pipe is connected with the cold air, the outlet of the third heat exchange pipe is connected with the first air supplement valve through a first branch pipe and connected with the air inlet pipe through a second branch pipe; the second spraying device is arranged at the upper part of the inner cavity of the third shell, the inlet of the second spraying device is connected with the activated carbon reactor through a reflux pipe, and the dilute sulfuric acid from the activated carbon reactor is sprayed downward to make the sulfur trioxide in the second process gas contact with the water in the dilute sulfuric acid to form sulfuric acid; the electrostatic demister is arranged at the top end of the inner cavity of the third shell and above the second spraying device, and the electrostatic demister is used for removing acid mist.

[0071] During operation, the second process gas enters the inner cavity of the third shell, exchanges heat with the cold air in the third heat exchange pipe and is condensed, the dilute sulfuric acid sprayed by the second spraying device contacts with the sulfur trioxide in the second process gas to generate a sulfuric acid solution with a higher concentration, and at the same time, the third process gas is obtained, the sulfuric acid solution is discharged from the liquid outlet of the third shell for storage, and the third process gas (containing a small amount of sulfur dioxide) enters the activated carbon reactor after passing through the electrostatic demister at the top end of the inner cavity of the third shell, and at the same time, the air in the third heat exchange pipe is heated to form hot air and enters the first air supplement valve (sulfur dioxide converter) and the air inlet pipe (incinerator) through the first branch pipe and the second branch pipe respectively, to supplement the oxygen concentration in the sulfur dioxide converter and to supplement the air and oxygen for the incinerator.

[0072] The activated carbon reactor is used for catalytically oxidizing the sulfur dioxide in the third process gas delivered by the condenser into sulfur trioxide, and forms dilute sulfuric acid under the spraying of desalted water.

[0073] The activated carbon reactor is internally provided with an activated carbon catalytic bed layer and a first spraying device, the loading amount of the activated carbon in the activated carbon catalytic bed layer is 80-100 m 3 , and the activated carbon catalytic bed layer is used for catalytically oxidizing the sulfur dioxide into sulfur trioxide; the first spraying device is used for spraying desalted water to convert the generated sulfur trioxide into sulfuric acid; the activated carbon reactor is communicated with the condenser through a reflux pipe, and the reflux pipe is used for refluxing the dilute sulfuric acid in the activated carbon reactor to the second spraying device, and the dilute sulfuric acid sprayed by the second spraying device contacts with the sulfur trioxide in the condenser to generate sulfuric acid.

[0074] Through the arrangement of the activated carbon reactor, the small amount of sulfur dioxide in the third process gas is catalytically oxidized, the formed dilute sulfuric acid is refluxed to the condenser to react with the sulfur trioxide to generate sulfuric acid, no waste water is generated, the conversion rate of sulfur dioxide is further increased, and the remaining tail gas of the activated carbon reactor is discharged up to the emission standard, i.e. the content of sulfur dioxide is extremely low to reach the emission index.

[0075] The embodiment of the present application also provides a process for preparing sulfuric acid from wet acid gas, which uses the device for preparing sulfuric acid from wet acid gas as described above to prepare sulfuric acid, and the process comprises the following steps:

[0076] (1) the acid gas containing hydrogen sulfide and air are combusted in the incinerator to generate first process gas rich in sulfur dioxide; in addition, fuel can be supplied to the incinerator through the fuel supply pipe when the acid gas containing hydrogen sulfide is combusted in the incinerator, the fuel being any one or more than one of natural gas and hydrocarbon compounds, so that the hydrogen sulfide is combusted sufficiently to generate sulfur dioxide;

[0077] (2) the first process gas enters the first waste heat boiler to be heat-exchanged and cooled, and then enters the sulfur dioxide converter, water in the first waste heat boiler is heated to form water vapor, which enters the first steam drum, and then enters the interlayer heat exchanger through a pipeline to remove heat from the catalyst bed;

[0078] (3) the sulfur dioxide in the first process gas is converted into sulfur trioxide in the sulfur dioxide converter to obtain second process gas rich in sulfur trioxide; the flow of hot air entering the second catalyst bed is adjusted by the first air supply valve according to the concentration of sulfur dioxide in the first process gas to adjust the oxygen concentration and heat removal of the second catalyst bed, and when over-temperature occurs in the third catalyst bed, cold air is introduced into the third catalyst bed through the second air supply valve for emergency cooling to avoid the loss of activity of the catalyst bed due to over-temperature;

[0079] (4) the second process gas enters the second waste heat boiler to be heat-exchanged and cooled, water in the second waste heat boiler is heated to form water vapor, which enters the interlayer heat exchanger through a pipeline to remove heat from the catalyst bed; the second process gas then enters the condenser to be heat-exchanged with air to be condensed, so that the sulfur trioxide in the second process gas is condensed and forms sulfuric acid under the spraying of dilute sulfuric acid, and the third process gas obtained at the same time enters the activated carbon reactor, a part of the hot air heated by the condenser enters the sulfur dioxide converter through the first branch pipe and the first air supply valve, and the other part of the hot air enters the air inlet pipe through the second branch pipe to mix with the acid gas containing hydrogen sulfide for air and oxygen supply;

[0080] (5) the sulfur dioxide in the third process gas is converted into sulfur trioxide under the catalytic oxidation of the activated carbon catalyst bed, the generated sulfur trioxide contacts with desalted water to obtain dilute sulfuric acid, and the sulfur dioxide in the remaining tail gas is discharged up to the standard;

[0081] (6) the dilute sulfuric acid generated in the activated carbon reactor enters the condenser through the reflux pipe to spray the sulfur trioxide inside the condenser, so that the sulfur trioxide is converted into sulfuric acid, and no waste water is generated.

[0082] Example 1

[0083] The acidic gas containing hydrogen sulfide, produced from the combustion of medium-sulfur coal upstream, along with the fuel gas, is fed into the incinerator for combustion at a temperature of 1000℃. Subsequently, the first process gas undergoes heat exchange in a high-temperature waste heat boiler, and after nitrogen oxide removal, it enters an adjustable SO2 converter with an inlet temperature of 410℃ and an inlet gas flow rate of 20503 Nm³. 3 The inlet SO2 concentration is 4.1% per hour. The outlet temperature of the first catalyst bed is 500℃. The inlet temperature of the second catalyst bed is 420℃, regulated by the first make-up air valve at the inlet, and the outlet temperature is 425℃. The inlet temperature of the third catalyst bed is 390℃, regulated by the second make-up air valve at the outlet of the second catalyst bed, and the outlet temperature is 392℃. The inlet temperature of the fourth catalyst bed is 390℃, and the outlet temperature is 391℃. The total SO2 conversion rate is 99.2%. The second process gas from the SO2 converter outlet, after heat exchange with a medium-temperature waste heat boiler, enters the bottom of the condenser and exchanges heat with cold air from the top of the condenser to condense into acid. The inlet temperature of the second process gas is 290℃, and the outlet temperature is 90℃. The third process gas from the condenser outlet is transported to the activated carbon reactor via pipeline. Trace amounts of SO2 are catalytically oxidized to SO3, and after being sprayed with demineralized water to form dilute sulfuric acid, it is returned to the top of the condenser for spraying. The final SO2 content of the third process gas is 5 mg / m³. 3 It was then discharged into the air through a chimney.

[0084] Example 2

[0085] The acidic gas and fuel gas produced from the combustion of low-sulfur coal upstream are fed into the incinerator for combustion at a temperature of 1000℃. The first process gas then passes through a high-temperature waste heat boiler for heat exchange, undergoes nitrogen oxide removal, and enters an adjustable SO2 converter with an inlet temperature of 410℃, an inlet gas flow rate of 8167 Nm³ / h, and an inlet SO2 concentration of 2.01%. The outlet temperature of the first catalyst bed is 463℃. The inlet temperature of the second catalyst bed is regulated to 410℃ via a first make-up air valve, and the outlet temperature is 415℃. The inlet temperature of the third catalyst bed is regulated to 390℃ via a second make-up air valve at the outlet of the second catalyst bed, and the outlet temperature is 392℃. The inlet temperature of the fourth catalyst bed is 390℃, and the outlet temperature is 391℃. The overall SO2 conversion rate is 99.4%. The second process gas from the SO2 converter outlet, after heat exchange with a medium-temperature waste heat boiler, enters the bottom of the condenser and condenses into acid by exchanging heat with cold air from the top of the condenser. The inlet temperature of the second process gas is 288℃, and the outlet temperature is 85℃. The third process gas from the condenser outlet is transported via pipeline to an activated carbon reactor where trace amounts of SO2 are catalytically oxidized to SO3. After being sprayed with demineralized water to form dilute sulfuric acid, it is returned to the top of the condenser for further spraying. The final SO2 content of the third process gas is 3 mg / m³.3 It was then discharged into the air through a chimney.

[0086] Example 3

[0087] The acidic gas and fuel gas produced from the combustion of upstream medium-sulfur coal are fed into the incinerator for combustion at a temperature of 1000℃. The first process gas then undergoes heat exchange in a high-temperature waste heat boiler, is denitrified, and then enters an adjustable SO2 converter with an inlet temperature of 410℃ and an inlet gas flow rate of 20590 Nm³. 3 The inlet SO2 concentration is 3.72%. The outlet temperature of the first catalyst bed is 499℃. The inlet temperature of the second catalyst bed is 420℃, regulated by the first make-up air valve at the inlet, and the outlet temperature is 425℃. The inlet temperature of the third catalyst bed is 390℃, regulated by the second make-up air valve at the outlet of the second catalyst bed, and the outlet temperature is 392℃. The inlet temperature of the fourth catalyst bed is 390℃, and the outlet temperature is 391℃. The total SO2 conversion rate is 99.2%. The second process gas from the SO2 converter outlet, after heat exchange with the medium-temperature waste heat boiler, enters the bottom of the condenser and exchanges heat with the cold air from the top of the condenser to condense into acid. The inlet temperature of the second process gas is 290℃, and the outlet temperature is 90℃. The third process gas from the condenser outlet is transported by pipeline to the activated carbon reactor. Trace amounts of SO2 are catalytically oxidized to SO3, and after being sprayed with demineralized water to form dilute sulfuric acid, it is returned to the top of the condenser for spraying. The final SO2 content of the third process gas is 5 mg / m³. 3 It was then discharged into the air through a chimney.

[0088] Example 4

[0089] The acidic gas and fuel gas produced from the combustion of high-sulfur coal upstream are fed into the incinerator for combustion at a temperature of 1100℃. The first process gas then undergoes heat exchange in a high-temperature waste heat boiler, is denitrified, and then enters an adjustable SO2 converter with an inlet temperature of 430℃ and an inlet gas flow rate of 20802 Nm³. 3 / h, the SO2 concentration at the inlet was 5.1%. The outlet temperature of the first catalyst bed was 541°C, the inlet temperature of the second catalyst bed was adjusted to 430°C by the first air supplement valve at the inlet of the second catalyst bed, the outlet temperature of the second catalyst bed was 455°C, the inlet temperature of the third catalyst bed was adjusted to 400°C by the second air supplement valve at the outlet of the second catalyst bed, the outlet temperature of the third catalyst bed was 410°C, the inlet temperature of the fourth catalyst bed was 400°C, and the outlet temperature of the fourth catalyst bed was 405°C. The total conversion rate of SO2 was 99.5%. The second process gas at the outlet of the SO2 converter was heat-exchanged by the medium-temperature waste heat boiler, and then condensed into acid by heat exchange with cold air from the top of the condenser. The inlet temperature of the second process gas was 295°C, and the outlet temperature was 90°C. The third process gas at the outlet of the condenser was transported by pipeline to the activated carbon reactor, a trace amount of SO2 was catalytically oxidized to SO3, and then diluted sulfuric acid was formed by spraying desalted water and returned to the top of the condenser for spraying. The final SO2 content of the third process gas was 8 mg / m 3 and then discharged through the chimney.

[0090] Example 5

[0091] The acid gas containing acid gas and fuel gas generated after the upstream medium-sulfur coal was burned were burned in the incinerator, the incineration temperature was 1000°C, and then the first process gas was heat-exchanged by the high-temperature waste heat boiler, removed nitrogen oxides, and then entered the adjustable SO2 converter, the inlet temperature was 390°C, the inlet gas flow was 9258 Nm 3 / h, the SO2 concentration at the inlet was 4.1%. The outlet temperature of the first catalyst bed was 530°C, the inlet temperature of the second catalyst bed was adjusted to 390°C by the first air supplement valve at the inlet of the second catalyst bed, and the outlet temperature of the second catalyst bed was 405°C. The inlet temperature of the third catalyst bed was adjusted to 400°C by the second air supplement valve at the outlet of the second catalyst bed, the outlet temperature of the third catalyst bed was 410°C, the inlet temperature of the fourth catalyst bed was 400°C, and the outlet temperature of the fourth catalyst bed was 405°C. The total conversion rate of SO2 was 99.2%. The second process gas at the outlet of the SO2 converter was heat-exchanged by the medium-temperature waste heat boiler, and then condensed into acid by heat exchange with cold air from the top of the condenser. The inlet temperature of the second process gas was 296°C, and the outlet temperature was 89°C. The third process gas at the outlet of the condenser was transported by pipeline to the activated carbon reactor, a trace amount of SO2 was catalytically oxidized to SO3, and then diluted sulfuric acid was formed by spraying desalted water and returned to the top of the condenser for spraying. The final SO2 content of the third process gas was 10 mg / m 3 and then discharged through the chimney.

[0092] Example 6

[0093] The acid gas containing acid gas and fuel gas generated after combustion of upstream high-sulfur coal is passed into a incinerator for combustion, the incineration temperature is 1100℃, then the first process gas is passed into an adjustable SO2 converter after heat exchange by a high-temperature waste heat boiler and removal of nitrogen oxides, the inlet temperature is 410℃, the inlet gas flow is 15828Nm 3 / h, the inlet SO2 concentration is 5.05%. The first catalyst bed outlet temperature is 519℃, the second catalyst bed inlet temperature is adjusted to 410℃ by a first air supplement valve at the inlet of the second catalyst bed, the second catalyst bed outlet temperature is 422℃, the third catalyst bed inlet temperature is adjusted to 400℃ by a second air supplement valve at the outlet of the second catalyst bed, the third catalyst bed outlet temperature is 409℃, the fourth catalyst bed inlet temperature is 390℃, and the fourth catalyst bed outlet temperature is 400℃. The total SO2 conversion rate is 99.7%. The second process gas at the outlet of the SO2 converter is passed into a condenser bottom and cold air from the condenser top for heat exchange and condensation into acid after heat exchange by a medium-temperature waste heat boiler, the second process gas inlet temperature is 289℃, and the outlet temperature is 88℃. The third process gas at the outlet of the condenser is transported to an activated carbon reactor by a pipeline, a trace amount of SO2 is catalytically oxidized into SO3, and then diluted sulfuric acid is formed by spraying desalted water and returned to the condenser top for spraying, the final SO2 content of the third process gas is 5mg / m 3 , and then discharged through a chimney.

[0094] Example 7

[0095] The acid gas containing acid gas and fuel gas generated after combustion of upstream low-sulfur coal is passed into a incinerator for combustion, the incineration temperature is 1000℃, then the first process gas is passed into an adjustable SO2 converter after heat exchange by a high-temperature waste heat boiler and removal of nitrogen oxides, the inlet temperature is 390℃, the inlet gas flow is 8050Nm 3 / h, the inlet SO2 concentration is 1.98%. The first catalyst bed outlet temperature is 440℃, the second catalyst bed inlet temperature is adjusted to 390℃ by a first air supplement valve at the inlet of the second catalyst bed, the second catalyst bed outlet temperature is 395℃, the third catalyst bed inlet temperature is adjusted to 390℃ by a second air supplement valve at the outlet of the second catalyst bed, the third catalyst bed outlet temperature is 393℃, the fourth catalyst bed inlet temperature is 390℃, and the fourth catalyst bed outlet temperature is 392℃. The total SO2 conversion rate is 99.5%. The second process gas at the outlet of the SO2 converter is passed into a condenser bottom and cold air from the condenser top for heat exchange and condensation into acid after heat exchange by a medium-temperature waste heat boiler, the second process gas inlet temperature is 290℃, and the outlet temperature is 90℃. The third process gas at the outlet of the condenser is transported to an activated carbon reactor by a pipeline, a trace amount of SO2 is catalytically oxidized into SO3, and then diluted sulfuric acid is formed by spraying desalted water and returned to the condenser top for spraying, the final SO2 content of the third process gas is 2mg / m 3 , and then discharged through a chimney.

[0096] While the application has been described by way of example with reference to preferred embodiments, it is to be understood that this application is not limited to the embodiments disclosed, but is intended to cover various arrangements or modifications thereof which fall within the spirit and scope of the application. Hence, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and / or as a representative way by which the features can be practiced. Therefore, it is to be understood that other alternatives and modifications to the application can be effected without departing from the spirit and scope of the application.

Claims

1. A plant for the production of sulfuric acid from wet acid gas, characterized in that, The incinerator, the first waste heat boiler, the sulfur dioxide converter, the second waste heat boiler, the condenser and the activated carbon reactor are sequentially connected by pipes; The sulfur dioxide converter comprises first, second, third and fourth catalyst beds arranged from top to bottom, and the second catalyst bed is provided with first and second air supplement valves for supplementing oxygen and emergency cooling at its inlet and outlet respectively, and inter-bed heat exchangers are arranged between the second and third catalyst beds and between the third and fourth catalyst beds; The condenser is connected with the first air supplement valve through a first branch pipe; The activated carbon reactor is internally provided with an activated carbon catalyst bed and a first spraying device for spraying desalted water, and a reflux pipe is arranged between the activated carbon reactor and the condenser for refluxing dilute sulfuric acid in the activated carbon reactor to the condenser to spray sulfur trioxide in the condenser.

2. The apparatus for the production of sulfuric acid from wet acid gas according to claim 1, characterized in that, The condenser comprises a third shell, third heat exchange pipes and a second spraying device; The inner cavity of the third shell is communicated with the second waste heat boiler and the activated carbon reactor through pipes respectively; The third heat exchange pipes are arranged in the inner cavity of the third shell, and the outlet of the third heat exchange pipes is connected with the first air supplement valve through the first branch pipe; The second spraying device is arranged at the top end of the inner cavity of the third shell, and the inlet of the second spraying device is connected with the outlet of the reflux pipe.

3. The wet acid gas sulphuric acid plant according to claim 2, c h a r a c t e r i s e d in that The incinerator is provided with an air inlet pipe and a fuel supplement pipe, and a second branch pipe is arranged between the air inlet pipe and the outlet of the third heat exchange pipes; The inlet and outlet of the second catalyst bed are respectively provided with first and second horizontal porous air column pipes; The first air supplement valve introduces hot air from the third heat exchange pipes into the first horizontal porous air column pipe, and the hot air mixes with process gas from the first catalyst bed and then enters the second catalyst bed to supplement oxygen and provide emergency cooling for the second catalyst bed; The second air supplement valve introduces cold air into the second horizontal porous air column pipe, and the cold air mixes with process gas from the second catalyst bed and then enters the third catalyst bed to supplement oxygen and provide emergency cooling for the third catalyst bed; Air filters are arranged at the air inlets of the first and second air supplement valves.

4. The wet acid gas sulphuric acid plant according to claim 3, c h a r a c t e r i s e d i n that The first waste heat boiler comprises a first shell, first heat exchange pipes and a first steam drum, the first heat exchange pipes are arranged in the inner cavity of the first shell, the inlet and outlet of the first heat exchange pipes are connected with the incinerator and the sulfur dioxide converter respectively, and the first steam drum is communicated with the inner cavity of the first shell; The second waste heat boiler comprises a second shell, second heat exchange pipes and a second steam drum, the second heat exchange pipes are arranged in the inner cavity of the second shell, the inlet and outlet of the second heat exchange pipes are connected with the sulfur dioxide converter and the condenser respectively, and the second steam drum is communicated with the inner cavity of the second shell; The inlet of the interlayer heat exchanger is connected with the outlet of the first steam drum and / or the second steam drum, so that the water vapor generated by the first steam drum and / or the second steam drum enters the interlayer heat exchanger to exchange heat with the first process gas and the second process gas, The acid gas containing hydrogen sulfide and air enter the incinerator to be combusted to generate the first process gas rich in sulfur dioxide; The sulfur dioxide in the first process gas is converted into sulfur trioxide in the sulfur dioxide converter to obtain the second process gas rich in sulfur trioxide.

5. The wet acid gas sulphuric acid plant according to claim 1, c h a r a c t e r i s e d i n that The first catalyst bed is filled with platinum-based catalyst, and the height of the first catalyst bed is 500-1000 mm; The platinum-based catalyst has an outer size of 150*150*600 mm or 150*150*300 mm 60-hole honeycomb catalyst, and the carrier used by the platinum-based catalyst is titanium dioxide; The second catalyst bed, the third catalyst bed and the fourth catalyst bed are all filled with vanadium-based catalyst, and the height of the second catalyst bed, the third catalyst bed and the fourth catalyst bed is 500-600 mm.

6. The wet acid gas sulphuric acid plant according to claim 1, characterized in that The activated carbon loading of the activated carbon catalytic bed is 80~100m 3 .

7. The wet acid gas sulphuric acid plant according to claim 1, c h a r a c t e r i s e d i n that The top end of the condenser is provided with an electrostatic demister for removing acid mist.

8. A process for the production of sulfuric acid from wet acid gas, characterized in that, The device for preparing sulfuric acid by using the wet method is used to prepare sulfuric acid, and the process includes the following steps: (1) The acid gas containing hydrogen sulfide and air enter the incinerator to be combusted to generate the first process gas rich in sulfur dioxide; (2) The first process gas enters the first waste heat boiler to be heat-exchanged and cooled, and then enters the sulfur dioxide converter; (3) The sulfur dioxide in the first process gas is converted into sulfur trioxide in the sulfur dioxide converter to obtain the second process gas rich in sulfur trioxide; the flow of hot air entering the second catalyst bed is adjusted by the first air supplement valve according to the concentration of sulfur dioxide in the first process gas, and the oxygen is supplemented and heat is removed by the hot air; when the third catalyst bed is overheated, the cold air is introduced into the third catalyst bed through the second air supplement valve to perform emergency cooling; (4) The second process gas enters the second waste heat boiler to be heat-exchanged and cooled, and then enters the condenser to be heat-exchanged with air to be condensed, so that the sulfur trioxide in the second process gas is condensed and forms sulfuric acid under the spraying of dilute sulfuric acid, and the third process gas obtained at the same time enters the activated carbon reactor; the hot air heated by the condenser enters the second catalyst bed through the first branch pipe and the first air supplement valve; (5) The sulfur dioxide in the third process gas is converted into sulfur trioxide under the catalytic oxidation of the activated carbon catalytic bed, the generated sulfur trioxide contacts with desalted water to obtain dilute sulfuric acid, and the sulfur dioxide in the remaining tail gas is discharged up to the standard; (6) The dilute sulfuric acid generated in the activated carbon reactor enters the condenser through the reflux pipe to spray the sulfur trioxide inside the condenser, so that the sulfur trioxide is converted into sulfuric acid, and no waste water is generated.

9. The wet acid gas sulfuric acid process of claim 8, wherein, Part of the hot air heated by the condenser enters the incinerator after being mixed with the acid gas containing hydrogen sulfide through the second branch pipe; Water vapor produced by the first waste heat boiler and / or the second waste heat boiler enters the inter-stage heat exchanger.

10. The process for the production of sulfuric acid from wet acid gas according to claim 8, characterized in that, The hydrogen sulfide-containing acid gas is combusted in an incinerator, and fuel is supplied to the incinerator through a fuel supply pipe, the fuel being a hydrocarbon fuel.

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