Industrial waste gas pre-desulfurization system

Abstract

The utility model discloses an industrial waste gas pre-desulfurization system which comprises a low-temperature methanol washing decarburization tower, the gas inlet end of the low-temperature methanol washing decarburization tower is connected with a tubular heat exchanger through a gas inlet pipeline, a pressure reduction control valve is arranged on the gas inlet pipeline, and the gas inlet end of the tubular heat exchanger is communicated with an air compressor through a tail gas pipeline. The input end of the air compressor is connected with a carbon dioxide pipeline, the tubular heat exchanger is further provided with a refrigerant input pipeline, a refrigerant output pipeline and a condensate water pipeline, and the other end of the condensate water pipeline is communicated with the low-temperature methanol washing decarburization tower. According to the industrial waste gas pre-desulfurization system, before entering the low-temperature methanol washing decarburization tower for desulfurization, tail gas needs to be subjected to positive pressure heating and heat exchange pressure reduction processes of the air compressor and the tubular heat exchanger, so that the temperature of the tail gas is reduced, and the tail gas can be kept at a lower temperature in the low-temperature methanol washing decarburization pretreatment process; the solubility of acid gas (such as carbon dioxide) in methanol is improved, and tail gas pretreatment is carried out for a desulfurization process.

Description

TECHNICAL FIELD

[0001] The utility model relates to a tail gas treatment technical field, concretely is a kind of industrial waste gas pre-desulfurization system. BACKGROUND

[0002] Industrial tail gas is usually the flue gas generated after sulfur-containing fuel combustion, because it contains sulfur dioxide and other sulfur oxides, it can cause harm to the environment and human health, etc., after sulfur dioxide is discharged into the atmosphere, it will react with oxygen and water vapor in the air to form a series of chemical reactions, such as sulfuric acid and other acidic substances, these acidic substances fall to the ground with the rainfall, forming acid rain, sulfur dioxide can enter the plant body through the stomata of the plant, interfering with the normal physiological function of the plant, sulfur dioxide is a gas with pungent smell, after human body inhales, it will have a strong stimulating effect on respiratory tract, causing cough, asthma, dyspnea and other symptoms, therefore, tail gas needs to be desulfurized before discharging.

[0003] Tail gas contains a large amount of sulfide and carbon dioxide, using the characteristics of methanol that has high solubility for acidic gas (such as carbon dioxide) at low temperature to remove carbon dioxide in raw gas, there is no absolute standard for whether to remove carbon dioxide first or sulfur first in industrial gas treatment, which needs to be specified according to the composition of the gas and the purpose of treatment, and the current tail gas cooling method is only through spray cooling, which not only cannot control the temperature well, but also is limited in cooling, affecting the solubility of methanol for acidic gas and subsequent desulfurization, so that the purpose of decarburization and desulfurization cannot be effectively achieved, therefore, the present application improves the existing technology, adds a decarburization system at the front end of the industrial waste gas pre-desulfurization system, and improves the decarburization system to pretreat the desulfurized tail gas, improve the cooling temperature of the tail gas and the solubility of methanol for acidic gas. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing an industrial waste gas pre-desulfurization system to solve the problems raised in the above background.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical scheme:

[0006] An industrial waste gas pre-desulfurization system, comprising a low-temperature methanol wash decarburization tower, the gas inlet end of the low-temperature methanol wash decarburization tower is connected with a tubular heat exchanger through a gas inlet pipeline, a pressure reducing control valve is arranged on the gas inlet pipeline, the gas inlet end of the tubular heat exchanger is communicated with an air compressor through a tail gas pipeline, the input end of the air compressor is connected with a carbon dioxide pipeline, the tubular heat exchanger is further provided with a refrigerant input pipeline, a refrigerant output pipeline and a condensate pipeline, the other end of the condensate pipeline is communicated with the low-temperature methanol wash decarburization tower.

[0007] As a further scheme of the utility model: the top of the low temperature methanol wash decarburization tower is provided with a gas outlet, the gas outlet is communicated with a buffer tank through a buffer pipeline, and the gas outlet end of the buffer tank is provided with a decarburization tail gas pipeline to send tail gas to the next process.

[0008] As a further scheme of the utility model: the bottom of the buffer tank is further provided with a liquid phase reflux pipeline communicated with a condensate water pipeline at the other end, and a pressurizing pump is arranged on the liquid phase reflux pipeline.

[0009] As a further scheme of the utility model: the low temperature methanol wash decarburization tower is provided with a liquid distribution pipeline and a liquid discharge pipeline, the liquid discharge pipeline is communicated with a pre-heating heat exchanger, and the liquid outlet end of the pre-heating heat exchanger is communicated with a thermal desorption pipeline to send methanol to a thermal desorption recovery.

[0010] As a further scheme of the utility model: the refrigerant output pipeline is connected with the medium input end of the pre-heating heat exchanger at the end away from the tubular heat exchanger, and the medium output end of the pre-heating heat exchanger is provided with a medium output pipeline.

[0011] Compared with the prior art, the utility model has the beneficial effects that:

[0012] 1、The industrial waste gas pre-desulfurization system, tail gas needs to pass through the positive pressure temperature rise and heat exchange pressure reduction process of the air compressor and the tubular heat exchanger before entering the low temperature methanol wash decarburization tower for desulfurization, reduces the tail gas temperature, makes it be able to keep lower temperature in the low temperature methanol wash decarburization pretreatment process, improves the solubility of acid gas (such as carbon dioxide) in methanol, and carries out tail gas pretreatment for the desulfurization process.

[0013] 2、The industrial waste gas pre-desulfurization system carries out decarburization before desulfurization pretreatment, uses the medium output by the tubular heat exchanger as the temperature rise medium of the pre-heating heat exchanger, uses it for the heating pretreatment of recovery liquid, utilizes heat energy, can effectively save the heat required in the thermal decomposition process, thereby achieving the purpose of energy saving. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a structural schematic view of an industrial waste gas pre-desulfurization system.

[0015] In the drawing: 1, low temperature methanol wash decarburization tower;2, tubular heat exchanger;3, air compressor;4, pre-heating heat exchanger;5, gas inlet pipeline;6, refrigerant output pipeline;7, refrigerant input pipeline;8, tail gas pipeline;9, carbon dioxide pipeline;10, thermal desorption pipeline;11, medium output pipeline;12, liquid discharge pipeline;13, liquid phase reflux pipeline;14, condensate water pipeline;15, buffer tank;16, decarburization tail gas pipeline;17, buffer pipeline. DETAILED DESCRIPTION

[0016] Please refer toFigure 1 The utility model discloses an industrial waste gas pre -desulfurization system, including low temperature methanol washes carbon tower 1, the gas inlet end of low temperature methanol washes carbon tower 1 through gas inlet pipeline 5 connects pipe -type heat exchanger 2, be provided with pressure reducing control valve on gas inlet pipeline 5, the gas inlet end of pipe -type heat exchanger 2 through tail gas pipeline 8 with air compressor 3 intercommunication, tail gas is usually high temperature, if it is local tail gas, temperature can reach 100 DEG C-200 DEG C, methanol is dissolved to acid gas such as carbon dioxide under low temperature, therefore this mode obviously can not reach, and the cooling mode such as usual water cooling is far from enough, for this increase air compressor 3, carry out a compression to tail gas, air temperature is elevated after compression, tail gas is by a large number of gas molecules composition. When compressing air, the distance between gas molecules reduces, the motion space of molecule becomes small, the frequency of mutual collision of molecule collision container wall and between molecules increases, the average kinetic energy of molecule increases, and temperature is the macroscopic performance of average kinetic energy of molecule, so the temperature of air is elevated, after tail gas is elevated by pressurization, enter into pipe -type heat exchanger 2, be provided with pressure reducing control valve on gas inlet pipeline 5, pressure reducing control valve controls pressure through the opening degree, after tail gas enters low temperature methanol washes carbon tower 1, pressure is released, temperature is low, is dissolved into methanol, completes the separation of carbon dioxide, pipe -type heat exchanger 2 reduces tail gas temperature after heat exchange, then through setting in, the input end of air compressor 3 connects carbon dioxide pipeline 9, pipe -type heat exchanger 2 still is provided with refrigerant input pipeline 7, refrigerant output pipeline 6 and condensate pipeline 14, the other end of condensate pipeline 14 communicates with low temperature methanol washes carbon tower 1, after tail gas is compressed, temperature is elevated, in the process of heat exchange cooling, will produce condensate, condensate is sent to low temperature methanol washes carbon tower 1 through condensate pipeline 14, together enters pyrogenetic analysis and recovers methanol.

[0017] In a preferred embodiment, the top of the low temperature methanol washes carbon tower 1 is provided with a gas outlet, which is communicated with the buffer tank 15 through a buffer pipeline 17, and the gas outlet end of the buffer tank 15 is provided with a decarbonization tail gas pipeline 16 to send the tail gas to the next process. The raw gas with a pressure of 0.03 MPa gauge pressure is reduced in carbon content by the low temperature methanol washes carbon tower 1, and after buffering and pressure stabilization by the buffer tank 15, it is sent to the next step of the carbon dioxide compressor for secondary pressurization and further treatment.

[0018] In a preferred embodiment, the bottom of the buffer tank 15 is further provided with a liquid phase reflux pipeline 13 which is communicated with the condensate pipeline 14 at the other end, and the liquid phase reflux pipeline 13 is provided with a pressurizing pump. The pressure in the buffer tank 15 is small, and the internal pressure of the pipe-type heat exchanger 2 is relatively large, so the liquid phase in the liquid phase reflux pipeline 13 needs to be pressurized to be injected into the low temperature methanol washes carbon tower 1. A valve can be provided on the condensate pipeline 14 to control the discharge of condensate.

[0019] In one preferred embodiment, the low-temperature methanol washing carbon stripping column 1 is provided with a liquid distribution pipeline 18 and a liquid discharge pipeline 12, the liquid discharge pipeline 12 is communicated with a pre-heating heat exchanger 4, the liquid outlet end of the pre-heating heat exchanger 4 is communicated with a thermal desorption pipeline 10 to send the thermal desorption recovered methanol, the methanol rich liquid absorbing carbon dioxide enters a desorption tower and other regeneration equipment, through the operations of pressure reduction, temperature increase and gas stripping, the carbon dioxide dissolved in the methanol is desorbed, generally a multi-stage desorption way is adopted to gradually separate the carbon dioxide from the methanol solution, the desorbed carbon dioxide gas can be processed and utilized subsequently, and the regenerated methanol lean liquid is pumped back to the absorption tower for recycling.

[0020] In one preferred embodiment, the refrigerant output pipeline 6 is connected to the medium input end of the pre-heating heat exchanger 4 far from one end of the tubular heat exchanger 2, the medium output end of the pre-heating heat exchanger 4 is provided with a medium output pipeline 11, the medium temperature is increased after passing through the tubular heat exchanger 2, and is input to the pre-heating heat exchanger 4 as a temperature increasing medium, which is used for heating pre-treatment of the recovered liquid, the heat energy is utilized, the heat required in the thermal decomposition process can be effectively saved, and the purpose of saving energy is achieved.

[0021] It should be noted that the above embodiments all belong to the same utility model concept, the description of each embodiment has different emphases, and the description not fully described in individual embodiments can be referred to the description in other embodiments.

[0022] The above described embodiments only express the implementation of the utility model, the description is more specific and detailed, but it should not be understood as the limitation of the utility model patent range. It should be noted that for ordinary skilled in the art, without departing from the utility model concept, a number of variations and improvements can be made, which all belong to the protection range of the utility model. Therefore, the protection range of the utility model patent should be subject to the appended claims.

Claims

1. An industrial waste gas pre-desulfurization system comprising a low-temperature methanol washing carbon removal tower (1), characterized in that, The low-temperature methanol washing carbon removal tower (1) is connected with the tubular heat exchanger (2) through the gas inlet pipeline (5), the gas inlet pipeline (5) is provided with a pressure reducing control valve, the gas inlet end of the tubular heat exchanger (2) is communicated with the air compressor (3) through the tail gas pipeline (8), the input end of the air compressor (3) is connected with the carbon dioxide pipeline (9), the tubular heat exchanger (2) is further provided with the refrigerant input pipeline (7), the refrigerant output pipeline (6) and the condensate pipeline (14), the other end of the condensate pipeline (14) is communicated with the low-temperature methanol washing carbon removal tower (1).

2. The industrial waste gas pre-desulfurization system according to claim 1, characterized in that, The top of the low-temperature methanol washing carbon removal tower (1) is provided with a gas outlet, the gas outlet is communicated with the buffer tank (15) through the buffer pipeline (17), the gas outlet end of the buffer tank (15) is provided with the decarbonization tail gas pipeline (16) to send the tail gas to the next process.

3. The system for pre-desulfurization of industrial exhaust gas according to claim 2, wherein The bottom of the buffer tank (15) is further provided with the liquid phase reflux pipeline (13) which is communicated with the condensate pipeline (14) at the other end, the liquid phase reflux pipeline (13) is provided with a pressurizing pump.

4. The industrial waste gas pre-desulfurization system according to claim 1, characterized in that, The low-temperature methanol washing carbon removal tower (1) is provided with the liquid distribution pipeline (18) and the liquid discharge pipeline (12), the liquid discharge pipeline (12) is communicated with the pre-heating heat exchanger (4), the liquid outlet end of the pre-heating heat exchanger (4) is communicated with the thermal desorption pipeline (10) to send the methanol to the thermal desorption recovery.

5. The industrial waste gas pre-desulfurization system according to claim 4, characterized in that, The refrigerant output pipeline (6) is connected with the medium input end of the pre-heating heat exchanger (4) at the end away from the tubular heat exchanger (2), the medium output end of the pre-heating heat exchanger (4) is provided with the medium output pipeline (11).

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