CN112999843A

CN112999843A - Purification process of exhaust gas containing hydrogen sulfide and organic sulfur

Info

Publication number: CN112999843A
Application number: CN202110007134.6A
Authority: CN
Inventors: 马磊; 张新波; 谭建冬; 梁立
Original assignee: Southwest Research and Desigin Institute of Chemical Industry
Current assignee: Southwest Research and Desigin Institute of Chemical Industry
Priority date: 2021-01-05
Filing date: 2021-01-05
Publication date: 2021-06-22

Abstract

The invention belongs to the field of exhaust gas treatment, in particular to a purification process for exhaust gas containing hydrogen sulfide and organic sulfur. The steps of the process are: (1) heating the exhaust gas containing hydrogen sulfide and organic sulfur to the activation temperature of the catalytic oxidation catalyst through a regenerative heating body; (2) the exhaust gas enters the catalytic oxidation reactor for oxidation reaction, and the hydrogen sulfide is oxidized. , organic sulfur, hydrocarbons and other harmful substances are converted into sulfur dioxide, sulfur trioxide, carbon dioxide and water; (3) the high-temperature gas after the reaction passes through the regenerator, which heats the regenerator for heating the next feed gas; (4) ) The gas after heat exchange enters the moving bed calcium oxide desulfurization reaction device to remove sulfur dioxide and sulfur trioxide; (5) Two regenerators are installed in front of the catalytic oxidation reactor for switching. The process of the invention has the characteristics of simplicity, high efficiency, low energy consumption and high purification degree.

Description

Purification process of exhaust gas containing hydrogen sulfide and organic sulfur

Technical Field

The invention belongs to the field of exhaust gas treatment, relates to the treatment of sulfur-containing flue gas pollution of coking, semi-coke and coal chemical enterprises, and particularly relates to a purification process of exhaust gas containing hydrogen sulfide and organic sulfur.

Background

The coking field. A large number of coking enterprises bring a large amount of coking tail gas emission, wherein sulfur dioxide, hydrogen sulfide, benzene and benzo [ a ] are contained in the coking tail gas emission]Pyrene is an atmospheric pollutant. According to the requirements, the content of the hydrogen sulfide in the tail gas discharged by the coke oven is required to be lower than 0.01mg/Nm³The content of sulfur dioxide is required to be less than 50mg/Nm³The limit of benzene concentration is 0.4g/Nm³Benzo [ a ]]The limiting value of the concentration of pyrene was 0.01. mu.g/Nm³。

Other areas of coalification. A certain amount of carbon dioxide gas is discharged from the low-temperature methanol washing section in coal gasification. Which contains about 200ppm of hydrogen sulfide and other organic sulfur.

Currently, there are two types of desulfurization treatments, dry desulfurization and wet desulfurization, for hydrogen sulfide, organic sulfur, and the like. The dry desulfurization mainly adsorbs and oxidizes hydrogen sulfide in gas through iron oxide or active carbon, but the problems of high regeneration difficulty and high replacement frequency of a desulfurizer in the method and the problem that sulfur formed in the desulfurization treatment process is fused with the desulfurizer are solved. The adsorbent used for wet coating absorbs hydrogen sulfide, and is easy to block, has large residual liquid amount and is difficult to recycle, and has large energy consumption.

Some of them are desulfurized by catalytic oxidation, but the catalyst is required to be high, and it is necessary to use a catalyst containing iron, titanium or the like as an active component, and only hydrogen sulfide is treated, and benzene compounds are removed by a separate apparatus, which makes the process complicated.

Therefore, it is necessary to develop a simple process for treating the above exhaust gas to meet the regulations and then exhaust the exhaust gas, thereby avoiding environmental pollution.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a purification process of exhaust gas containing hydrogen sulfide and organic sulfur. The process has the advantages of simple flow, low investment, high conversion rate, good adaptability, capability of purifying various pollutants in the exhaust gas, good purification effect and accordance with or better than the emission standard.

In order to achieve the above purposes, the invention adopts the technical scheme that:

a purification process of exhaust gas containing hydrogen sulfide and organic sulfur comprises the following steps: the normal-temperature exhaust gas which does not reach the emission standard after the primary treatment enters a catalytic oxidation reactor for catalytic oxidation reaction after being regulated by a program control valve; in the reactor, hydrocarbons, carbon monoxide, hydrogen sulfide and the like in the flue gas are subjected to catalytic oxidation, so that the temperature of the flue gas is increased and the flue gas is converted into carbon dioxide and sulfur dioxide; high-temperature gas at the outlet of the reactor enters a second heat accumulator through the regulation of a program control valve, the second heat accumulator is heated, and tail gas after the second heat accumulator is heated enters a moving bed calcium oxide desulfurization device for desulfurization treatment, so that the content of sulfur dioxide is reduced to be below 0.5 ppm.

As a better implementation mode in the application, the normal-temperature exhaust gas needs to be heated to 160-350 ℃ by a heat accumulator before entering the catalytic oxidation reactor; the heat source for heating the heat accumulator is flue gas at the outlet of the catalytic oxidation reactor.

In a preferred embodiment of the present invention, the heat storage body is a cold heat storage body. In order to meet the requirement of the reaction temperature of the catalytic oxidation catalyst, the device adopts a heat accumulator heating mode to heat. The heat accumulator is heated by hot gas at the outlet of the catalytic oxidation reactor, and then is used as inlet cold gas for heating.

As a better implementation mode in the application, the heat accumulator is arranged in a double-channel mode, and the gas flow direction is controlled through two program control valves to heat the heat accumulator or heat gas by the heat accumulator.

As a better implementation mode in the application, the flue gas enters the catalytic oxidation reaction bed layer for reaction, and the space velocity of the catalytic oxidation reactor bed layer is 100h^-1～5000h^-1。

As a better implementation mode in the application, the catalytic oxidation reactor bed layer adopts a catalytic oxidation catalyst as a main catalyst, and the main component of the catalyst is titanium dioxide.

As a preferred embodiment of the present application, the heat source for heating the heat storage body may be a heat source supplemented by a fuel gas combustion heating device, wherein the fuel gas is coke oven gas or other combustible gas.

As a preferred embodiment in the present application, the moving bed calcium oxide desulfurization device is a desulfurization bed, and the sulfur content of the flue gas after desulfurization is superior to that of SO in the emission standard of pollutants for coking industry (GB16171-2012)₂≤50mg/Nm³The specification of (1).

As a better embodiment in the application, in the catalytic oxidation reactor, pollutants such as benzene, benzo [ a ] pyrene and the like in the flue gas are fully combusted, and the content of benzene and benzene compounds in the flue gas after desulfurization treatment by the moving bed calcium oxide desulfurization device is less than 0.1 ppm.

The process is also suitable for treating various industrial exhaust gases containing sulfur, such as coking flue gas, semi-coke tail gas, refinery gas, converter gas or low-temperature methanol scrubbing exhaust gas and the like.

As a preferred embodiment in the present application, the catalyst used in the catalytic oxidation reactor may be a clean-up catalyst (e.g., a catalyst in chinese patent CN 108722169a or CN 109603459 a) from southwestern chemical research and design institute limited company.

In a preferred embodiment of the present invention, the catalyst used for desulfurization is a calcium oxide desulfurizing agent (e.g., the catalyst described in chinese patent CN 108722169a or CN 109603459 a) from southwestern chemical research and design institute co.

Compared with the prior art, the positive effects of the invention are as follows:

purifying sulfur-containing exhaust gas by adopting a catalytic oxidation method, and matching with a calcium oxide moving bed desulfurization method to ensure that the sulfur-containing exhaust gas can reach the emission standard.

And (II) the process is simple, a large amount of additional equipment is not required, and the cost is low.

And (III) high conversion rate and good adaptability, and can simultaneously purify various pollutants.

And (IV) the method has wide application range, and is suitable for treating various industrial sulfur-containing exhaust gases, such as coking flue gas, semi-coke tail gas, refinery gas, converter gas or low-temperature methanol scrubbing exhaust gas and the like.

Drawings

FIG. 1 is a schematic process flow diagram of the present invention.

Detailed Description

The invention is further explained below with reference to examples and figures.

As shown in fig. 1, a process for purifying an exhaust gas containing hydrogen sulfide and organic sulfur, comprises the following steps:

the X gas containing hydrogen sulfide and organic sulfur is used as the exhaust gas, the exhaust gas enters the boundary area of the device, is heated to 160-350 ℃ by the heat accumulator A, and then enters the catalytic oxidation reactor for reaction. The air velocity of the catalytic bed layer is 100h^-1～5000h^-1In the catalytic bed layer, organic substances such as benzene and compounds, carbon monoxide, hydrogen sulfide, methane and the like are oxidized and release heat. If the outlet temperature of the catalytic oxidation reactor can not reach the temperature required by the heating heat accumulator, an external source synthesis gas combustion heating device is adopted to supplement heat. The high-temperature exhaust gas after catalytic oxidation passes through the heat storage body B and heats the heat storage body. The heated heat accumulator B is used for next purification and heating, the exhaust gas after heat exchange enters a calcium oxide movable desulfurization bed, and the exhaust gas is treated by the heat exchangeSulfur dioxide removal to 0.5mg/Nm³Then sent into a chimney. The heat accumulator A and the heat accumulator B are used alternately, and heat is provided through the hot exhaust gas at the outlet and the cold exhaust gas at the inlet.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1:

according to the process flow shown in FIG. 1, the dry basis flow rate of the coking flue gas is 150000Nm³H, pressure 0.6kPag, temperature 70 ℃. The composition (mole fraction, dry basis) of the flue gas is N₂81.7% of CO, 1.0% of CO₂3.0% of oxygen, O₂Accounting for 13.0 percent. The impurity contains 500mg/Nm of hydrogen sulfide³350mg/Nm of sulfur dioxide³Benzene and other organic Compounds 50mg/Nm³. Heating the flue gas to 200 ℃ through a heat accumulator A, allowing the flue gas to enter a catalytic oxidation reactor bed layer and carrying out oxidation reaction, reacting hydrogen sulfide to generate sulfur dioxide and water, oxidizing benzene and other organic matters into carbon dioxide and water, oxidizing the carbon monoxide into carbon dioxide, wherein the outlet temperature of the catalytic oxidation reactor is 295 ℃, and the outlet sulfur dioxide content is 850mg/Nm³The content of benzene and other organic matters is less than 0.01mg/Nm³Only traces of hydrogen sulfide, benzene and other organics did not react to completion. The high-temperature flue gas at the outlet passes through the heat accumulator B, and the flue gas is cooled to 205 ℃ while the heat accumulator B is heated to 200 ℃. The flue gas enters a moving bed desulfurization reactor through a pipeline, and sulfur dioxide in the flue gas is removed to be less than 20mg/Nm by utilizing a calcium oxide desulfurizer³. And (4) the flue gas reaching the standard enters a chimney to be discharged.

Example 2:

according to the process flow shown in figure 1, the dry basis flow of the coking flue gas is 200000Nm³H, pressure 0.5kPag, temperature 55 ℃. The composition (mole fraction, dry basis) of the flue gas is N₂81.7% of CO, 0.2% of CO₂3.0% of oxygen, O₂Accounting for 14.0 percent. The impurity contains 400mg/Nm of hydrogen sulfide³Oxidation of carbon dioxideSulfur 550mg/Nm³Benzene and other organic Compounds 70mg/Nm³. Heating the flue gas to 160 ℃ through a heat accumulator A, heating the flue gas to 200 ℃ through heat provided by an external hot blast stove, allowing the flue gas to enter a catalytic oxidation reactor bed layer to perform oxidation reaction, allowing hydrogen sulfide to react to generate sulfur dioxide and water, oxidizing benzene and other organic matters into carbon dioxide and water, oxidizing the carbon dioxide into carbon dioxide, and allowing the outlet temperature of the catalytic oxidation reactor to be 230 ℃ and the outlet sulfur dioxide content to be 950mg/Nm³The content of benzene and other organic matters is less than 0.01mg/Nm³Only traces of hydrogen sulfide, benzene and other organics did not react to completion. The high-temperature flue gas at the outlet passes through the heat accumulator B, and the flue gas is cooled to 165 ℃ while the heat accumulator B is heated to 160 ℃. The flue gas enters a moving bed desulfurization reactor through a pipeline, and sulfur dioxide in the flue gas is removed to less than 20mg/Nm by using a calcium oxide desulfurizer³. And the flue gas reaching the standard enters a chimney to be discharged.

Example 3:

according to the process flow shown in figure 1, the dry basis flow rate of the low-temperature methanol scrubbing exhaust gas is 400000Nm³H, pressure 0.5kPag, temperature 30 ℃. The composition (mole fraction, dry basis) of the flue gas is N₂24.7 percent of CO, 0.52 percent of CO₂75.19% of H₂Accounting for 0.02 percent. The impurity contains 100mg/Nm of hydrogen sulfide³Sulfur, oxygen and carbon 100mg/Nm³. After the flue gas is heated to 230 ℃ by the heat accumulator A, the flue gas is heated to 250 ℃ by heat provided by an external hot blast stove, enters a catalytic oxidation reactor bed layer and undergoes an oxidation reaction, hydrogen sulfide reacts to generate sulfur dioxide and water, benzene and other organic matters are oxidized into carbon dioxide and water, the carbon monoxide is oxidized into carbon dioxide, the outlet temperature of the catalytic oxidation reactor is 270 ℃, and the outlet sulfur dioxide content is 200mg/Nm 3. The high-temperature flue gas at the outlet passes through the heat accumulator B, and the flue gas is cooled to 235 ℃ while the heat accumulator B is heated to 230 ℃. The flue gas enters a moving bed desulfurization reactor through a pipeline, and sulfur dioxide in the flue gas is removed to be less than 5mg/Nm by utilizing a calcium oxide desulfurizer³. And (4) the flue gas reaching the standard enters a chimney to be discharged.

Example 4:

according to the process flow shown in figure 1, the dry basis flow rate of the sulfur-containing exhaust gas is 200000Nm³H, a pressure of 0.5kPag and a temperature of 30 ℃. The composition (mole fraction, dry basis) of the flue gas is N₂22.7 percent of CO, 0.53 percent of CO₂78.19%, H₂Accounting for 0.01 percent. The impurity contains 150mg/Nm of hydrogen sulfide³Sulfur, oxygen and carbon 150mg/Nm³. After the flue gas is heated to 190 ℃ by the heat accumulator A, the flue gas is heated to 250 ℃ by heat provided by an external hot blast stove and enters a catalytic oxidation reactor bed layer to react to generate sulfur dioxide and water, benzene and other organic matters are oxidized into carbon dioxide and water, the carbon monoxide is oxidized into carbon dioxide, the outlet temperature of the catalytic oxidation reactor is 270 ℃, and the outlet sulfur dioxide content is 300mg/Nm 3. The high-temperature flue gas at the outlet passes through a heat accumulator B, is cooled to 235 ℃, enters a moving bed desulfurization reactor, and sulfur dioxide in the flue gas is removed to less than 10mg/Nm by using a calcium oxide desulfurizer³. And (4) the flue gas reaching the standard enters a chimney to be discharged. Contrast other catalytic oxidation desulfurization and adopt the technical scheme who turns into elemental sulfur with hydrogen sulfide, this patent is sulfur dioxide, sulfur trioxide etc. with the direct oxidation of hydrogen sulfide, and the reaction is controllable, the pollution is still less. The calcium sulfate has better adaptability to sulfides such as sulfur, oxygen, carbon, thiophene and the like, and high-purity calcium sulfate can be obtained through a cheap calcium oxide desulfurizer after catalytic oxidation, so that gypsum can be directly produced.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.

Claims

1. the purification process containing hydrogen sulfide and organic sulfur exhaust gas is characterized in that comprising the steps: through preliminary treatment, the normal temperature exhaust gas that does not reach the emission standard, enters the catalytic oxidation reactor after being regulated by the process control valve and carries out catalytic oxidation reaction; this reaction The reactor catalyzes the oxidation of hydrocarbons, carbon monoxide, hydrogen sulfide, etc. in the flue gas, and converts the flue gas into carbon dioxide and sulfur dioxide while increasing the temperature of the flue gas; The second heat storage body is heated, and the exhaust gas after heating the second heat storage body enters the moving bed calcium oxide desulfurization device for desulfurization treatment, so that the content of sulfur dioxide is reduced to below 0.5ppm.

2. The purification process of exhaust gas containing hydrogen sulfide and organic sulfur according to claim 1, characterized in that: the exhaust gas at normal temperature must be heated to 160-350 °C by a regenerator before entering the catalytic oxidation reactor. ℃; the heat source for heating the regenerator comes from the flue gas at the outlet of the catalytic oxidation reactor.

3. The purification process of containing hydrogen sulfide and organic sulfur exhaust gas according to claim 1, is characterized in that: described regenerator is divided into two channels and is arranged, and the gas flow is controlled by two program-controlled valves to heat the regenerator or use The regenerator heats the gas.

4 . The coking sulfur-containing flue gas purification process according to claim 1 , wherein the space velocity of the catalytic oxidation reactor bed is 100h ^-1 to 5000h ^-1 . 5 .

5. The coking sulfur-containing flue gas purification process according to claim 1, wherein the catalytic oxidation reactor bed adopts a catalytic oxidation catalyst as the main catalyst, and the main component of the catalyst is titanium dioxide.

6. according to the purification process of containing hydrogen sulfide and organic sulfur exhaust gas described in claim 2, it is characterized in that: the heat source that heat accumulator one heats can also be to utilize fuel gas combustion heating device to supplement heat, and fuel gas selects coke oven for use Gas or other combustible gases.

7. the purification process of containing hydrogen sulfide and organic sulfur exhaust gas according to claim 1 is characterized in that: the described moving bed calcium oxide desulfurization device is a desulfurization bed, and the flue gas sulfur content after desulfurization is better than "coking". SO ₂ ≤50mg/Nm ³ in Industrial Pollutant Emission Standard (GB16171-2012).

8 . The purification process of hydrogen sulfide and organic sulfur-containing exhaust gas according to claim 1 , wherein the content of benzene and benzene compounds is less than 0.1 ppm in the flue gas after desulfurization treatment by the moving bed calcium oxide desulfurization device. 9 .

9. The purification process of hydrogen sulfide and organic sulfur-containing exhaust gas according to any one of claims 1 to 8, wherein the process is suitable for the treatment of various sulfur-containing industrial exhaust gases.

10. The purification process of hydrogen sulfide and organic sulfur-containing exhaust gas as claimed in claim 9, characterized in that: the various types of sulfur-containing industrial exhaust gases are coking flue gas, blue carbon tail gas, refinery gas, converter gas Or low temperature methanol wash exhaust gas.