Feed gas deep purification system

Abstract

The utility model relates to the technical field of gas purification, in particular to a feed gas deep purification system. The embodiment of the utility model provides a feed gas deep purification system. The feed gas deep purification system comprises a cleaning system, a low-temperature methanol washing system, a decomposition system and a filtering system which are connected in sequence. The low-temperature methanol washing system is used for removing acid gas in raw material gas, the low-temperature methanol washing system comprises an absorption tower storing a methanol solution, and the absorption tower is provided with a liquid inlet and a liquid outlet. According to the feed gas deep purification system provided by the invention, the low-temperature methanol washing system comprises the absorption tower in which the methanol solution is stored, and the absorption tower is provided with the liquid inlet and the liquid outlet, so that after the methanol solution is saturated, a certain amount of methanol solution is directly added through the liquid inlet, and a certain amount of saturated methanol solution is discharged through the liquid outlet; and the methanol solution in the absorption tower can be diluted without being replaced in a carrying manner, so that the manpower is greatly saved, and the safety is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of gas purification, in particular to a raw gas deep purification system. Background Art

[0002] In the field of mixed gas anaerobic bio-fermentation, the cleanliness of raw gas treatment directly affects the health of fermentation bacteria. Only healthy bacteria can ensure the continuous production of fuel ethanol. There is acidic gas in the raw gas. In related technologies, the acidic gas in the raw gas is removed by TSA (Temperature Swing Adsorption) purification system, that is, the acidic gas in the raw gas is adsorbed by adsorbent. In order to ensure the adsorption effect of TSA purification system, saturated fillers need to be replaced regularly. Since TSA purification system is a closed tower structure, there are safety risks such as suffocation in closed space operations, and carrying fillers is also time-consuming and laborious. Utility Model Content

[0003] The present application provides a raw gas deep purification system, which solves the technical problems in the related technology that in order to ensure the adsorption effect of the TSA purification system, the packing needs to be replaced regularly. Since the TSA purification system is a closed tower structure, operations in a closed space have safety risks such as suffocation, and are time-consuming and labor-intensive.

[0004] The present application provides a raw gas deep purification system, comprising:

[0005] Cleaning system, used to remove impurities from the raw gas;

[0006] A low-temperature methanol washing system, used to remove acidic gases in the feed gas, wherein the low-temperature methanol washing system comprises an absorption tower storing a methanol solution, and the absorption tower has a liquid inlet and a liquid outlet;

[0007] a decomposition system for decomposing the raw gas to generate hydrogen sulfide;

[0008] A filtration system is used to filter the raw gas.

[0009] In some embodiments, the cleaning system includes a connected impurity removal unit and a gas-liquid separation unit, the gas-liquid separation unit is connected to the low-temperature methanol washing system, the impurity removal unit is used to remove impurities in the raw gas, and the gas-liquid separation unit is used to remove free water in the raw gas.

[0010] In some embodiments, the impurity removal unit includes a water washing tower, a cooling tower and a decoking tower which are connected in sequence, the decoking tower is connected to the gas-liquid separation unit, the water washing tower is used to remove dust in the raw gas, the cooling tower is used to cool the raw gas, and the decoking tower is used to remove tar in the raw gas.

[0011] In some embodiments, the gas-liquid separation unit includes a buffer tank, a compression tank and a gas-liquid separation tank connected in sequence, the buffer tank is connected to the impurity removal unit, the gas-liquid separation tank is connected to the low-temperature methanol washing system, and the gas-liquid separation tank is used to remove free water in the raw gas.

[0012] In some embodiments, the decomposition system includes a mixing unit, a deoxygenation unit, and a decomposition unit that are connected in sequence, the mixing unit is connected to the low-temperature methanol washing system, and the decomposition unit is connected to the filtration system.

[0013] In some embodiments, the mixing unit includes a connected purified gas buffer tank and a gas mixing tank, the purified gas buffer tank is connected to the low-temperature methanol washing system, the gas mixing tank is connected to the deoxygenation unit, and the purified gas buffer tank is used to purify the raw gas.

[0014] In some embodiments, the deoxygenation unit includes a heat exchanger, a heater and a deoxygenation tower which are arranged in sequence, a circulation loop is formed between the heat exchanger, the heater and the deoxygenation tower, and the heat exchanger is connected to the mixing unit and the decomposition unit respectively, the heater is used to heat the raw gas, and the deoxygenation tower deoxygenates the raw gas.

[0015] In some embodiments, the decomposition unit comprises a thermostat and a carbonyl sulfide decomposer, and the carbonyl sulfide decomposer is used to decompose the feed gas to generate hydrogen sulfide.

[0016] In some embodiments, the filtration system includes a cooling unit and a filtration unit, the cooling unit is connected to the decomposition system, the filtration unit is connected to the gas use end, the cooling unit is used to cool the raw gas, and the filtration unit is used to filter the raw gas.

[0017] In some embodiments, the cooling unit is a water cooler, and the filtering unit includes a gas-liquid separator and a filter that are connected, and the gas-liquid separator is connected to the water cooler.

[0018] The beneficial effects of this application are as follows:

[0019] The present application provides a raw gas deep purification system, which adopts a low-temperature methanol washing system to remove acidic gases in the raw gas. Since the low-temperature methanol washing system includes an absorption tower storing a methanol solution, and the absorption tower has a liquid inlet and a liquid outlet, when the methanol solution is saturated, a certain amount of methanol solution is directly added through the liquid inlet, and a certain amount of saturated methanol solution is discharged through the liquid outlet, so as to dilute the methanol solution in the absorption tower. There is no need to replace the methanol solution by transporting it, which greatly saves manpower and ensures safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model.

[0021] Figure 1 This is a schematic diagram of the structure of the raw gas deep purification system provided in an embodiment of the present application.

[0022] Description of reference numerals:

[0023] 100-cleaning system, 110-impurity removal unit, 111-water washing tower, 112-cooling tower, 113-decoking tower, 120-gas-liquid separation unit, 121-buffer tank, 122-compression tank, 123-gas-liquid separation tank, 200-low-temperature methanol washing system, 300-decomposition system, 310-mixing unit, 311-purified gas buffer tank, 312-gas mixing tank, 320-deoxygenation unit, 321-heat exchanger, 322-heater, 323-deoxygenation tower, 330-decomposition unit, 331-thermostat, 332-carbonyl sulfide decomposer, 400-filtration system, 410-cooling unit, 420-filtration unit, 421-gas-liquid separator, 422-filter. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0026] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In addition, in the present utility model, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0028] The embodiment of the present application provides a raw gas deep purification system, comprising a cleaning system 100, a low-temperature methanol washing system 200, a decomposition system 300 and a filtering system 400 connected in sequence. The cleaning system 100 is used to remove impurities in the raw gas, the low-temperature methanol washing system 200 is used to remove acidic gases in the raw gas, the low-temperature methanol washing system 200 includes an absorption tower storing a methanol solution, the absorption tower has a liquid inlet and a liquid outlet, the decomposition system 300 is used to decompose the raw gas to generate hydrogen sulfide, and the filtering system 400 is used to filter the raw gas.

[0029] The cleaning system 100 is connected to the upstream gas supply system, and is used to clean the impurities in the raw gas after preliminary pressurization. The raw gas with free water removed enters the low-temperature methanol washing system 200 for deep purification and separation. The low-temperature methanol washing uses cold methanol as an absorbent, and utilizes the physical property of methanol having a large solubility in acidic gases at low temperatures to remove the acidic gases in the raw gas. The raw gas free of acidic gases enters the decomposition system 300, and the decomposition system 300 is used to decompose the raw gas to generate hydrogen sulfide. Hydrogen sulfide can participate in subsequent anaerobic biological fermentation production and can be used as a source of sulfur in biological fermentation for supplementation. The decomposed raw gas finally enters the filtration system 400 for filtration, and finally reaches the use conditions at the gas user end.

[0030] Low-temperature methanol washing uses cold methanol as the absorption solvent, and utilizes the excellent property of methanol's great solubility in acidic gases at low temperatures to remove acidic gases from the raw gas. Low-temperature methanol washing can remove a variety of impurities from the gas. At low temperatures of -30°C to -70°C, methanol can simultaneously remove H2S, COS, CS2, RSH, C4H4S, CO2, HCN, NH3, NO, as well as paraffin, aromatic hydrocarbons, crude gasoline and other impurities from the gas, and can simultaneously dehydrate the gas to make it completely dry. The absorbed useful components can be recovered during the regeneration process of methanol. The low-temperature methanol washing system 200 generally includes an absorption tower and multiple analysis towers. The absorption tower absorbs acidic gases, and the absorption tower has a liquid inlet and a liquid outlet to replenish the methanol solution. The analysis tower analyzes the acidic gases and returns the lean liquid methanol to the absorption tower to achieve the recycling of methanol. The low-temperature methanol washing system 200 can use the equipment in the prior art, and its structure and principle will not be repeated here.

[0031] The present application provides a raw gas deep purification system, which adopts a low-temperature methanol washing system 200 to remove acidic gases in the raw gas. Since the low-temperature methanol washing system 200 includes an absorption tower storing a methanol solution, and the absorption tower has a liquid inlet and a liquid outlet, when the methanol solution is saturated, a certain amount of methanol solution is directly added through the liquid inlet, and a certain amount of saturated methanol solution is discharged through the liquid outlet, so as to dilute the methanol solution in the absorption tower. There is no need to replace the methanol solution by transportation, which greatly saves manpower and ensures safety.

[0032] In some embodiments, the cleaning system 100 includes a connected impurity removal unit 110 and a gas-liquid separation unit 120, the gas-liquid separation unit 120 is connected to the low-temperature methanol washing system 200, the impurity removal unit 110 is used to remove impurities in the raw gas, and the gas-liquid separation unit 120 is used to remove free water in the raw gas.

[0033] In some embodiments, the impurity removal unit 110 includes a water washing tower 111, a cooling tower 112 and a decoking tower 113 which are connected in sequence, the decoking tower 113 is connected to the gas-liquid separation unit 120, the water washing tower 111 is used to remove dust in the raw gas, the cooling tower 112 is used to cool the raw gas, and the decoking tower 113 is used to remove tar in the raw gas.

[0034] The water washing tower 111 is connected to the upstream gas supply system. The raw gas after initial pressurization enters the water washing tower 111 for deep water washing, which can wash most of the dust out of the system; the cooling tower 112 cools the washed raw gas, which can effectively cool the raw gas in hot summer weather to ensure that the gas supply temperature does not impact the system, and it does not need to be operated in winter. The cooled raw gas is further passed through the decoking tower 113 of the electric coke collector or the packed adsorption tower to remove tar, and can also remove a small amount of benzene and naphthalene impurities, and the raw gas is initially decontaminated.

[0035] In some embodiments, the gas-liquid separation unit 120 includes a buffer tank 121, a compression tank 122 and a gas-liquid separation tank 123 which are connected in sequence, the buffer tank 121 is connected to the impurity removal unit 110, the gas-liquid separation tank 123 is connected to the low-temperature methanol washing system 200, and the gas-liquid separation tank 123 is used to remove free water in the raw gas.

[0036] The initially purified raw gas is buffered in the buffer tank 121 before entering the compressor for boosting, to ensure stable air intake of the compressor and prevent the compressor from tripping; the compressor further boosts the raw gas to ensure stable air intake of the fermentation tank; the upstream of the gas-liquid separation tank 123 is connected to the outlet of the compressor to remove free water in the compressed gas.

[0037] In some embodiments, the decomposition system 300 includes a mixing unit 310, a deoxygenation unit 320, and a decomposition unit 330 that are sequentially connected, the mixing unit 310 is connected to the low-temperature methanol washing system 200, and the decomposition unit 330 is connected to the filtering system 400. The mixing unit 310 is used to mix the raw gas to make each gas component fully uniform, the deoxygenation unit 320 is used to deoxygenate the gas, and the decomposition unit 330 is used to decompose the raw gas to generate hydrogen sulfide.

[0038] In some embodiments, the mixing unit 310 includes a connected purified gas buffer tank 311121 and a gas mixing tank 312, the purified gas buffer tank 311121 is connected to the low-temperature methanol washing system 200, the gas mixing tank 312 is connected to the deoxygenation unit 320, and the purified gas buffer tank 311121 is used to purify the raw gas.

[0039] After the low-temperature methanol washing system 200 purifies the raw gas, the purified gas enters the purified gas buffer tank 311121 for pressure stabilization, and the liquid entrained in the gas is separated, and the liquid is discharged from the bottom of the enterprise buffer tank 121; the clean gas after buffering is fully mixed in the gas mixing tank 312 to make the gas components fully uniform.

[0040] In some embodiments, the deoxygenation unit 320 includes a heat exchanger 321, a heater 322 and a deoxygenation tower 323 which are arranged in sequence, a circulation loop is formed among the heat exchanger 321, the heater 322 and the deoxygenation tower 323, and the heat exchanger 321 is connected to the mixing unit 310 and the decomposition unit 330 respectively, the heater 322 is used to heat the raw gas, and the deoxygenation tower 323 deoxygenates the raw gas.

[0041] Only when the temperature of the raw gas reaches about 280°C, the catalyst for deoxygenation in the deoxygenation tower 323 can achieve the deoxygenation effect. Therefore, before the gas enters the deoxygenation tower 323, it needs to be heated by the heater 322 to make the gas reach 280°C. Since a circulation loop is formed between the heat exchanger 321, the heater 322 and the deoxygenation tower 323, that is, the high-temperature raw gas after deoxygenation will enter the heat exchanger 321, the low-temperature raw gas without deoxygenation from the mixing unit 310 and the high-temperature raw gas after deoxygenation are heat exchanged in the heat exchanger 321, and then enter the heater 322, which can reduce the energy consumption of the heater 322 for heating the gas that continuously enters the deoxygenation tower 323, and the oxygen-free gas after deoxygenation enters the subsequent process.

[0042] In some embodiments, the decomposition unit 330 includes a thermostat 331 and a carbonyl sulfide decomposer 332. The carbonyl sulfide decomposer 332 is used to decompose the raw gas to generate hydrogen sulfide. The temperature of the gas after deoxygenation is relatively high, so it needs to be cooled by the thermostat 331. The carbonyl sulfide is fully decomposed after the temperature is adjusted to 80°C. The deoxygenated raw gas passes through the carbonyl sulfide decomposer 332 for carbonylation reaction. The hydrogen sulfide generated after decomposition can participate in the subsequent anaerobic biological fermentation production and can be supplemented as a source of sulfur in biological fermentation.

[0043] In some embodiments, the filtration system 400 includes a cooling unit 410 and a filtration unit 420. The cooling unit 410 is connected to the decomposition system 300, and the filtration unit 420 is connected to the gas use end. The cooling unit 410 is used to cool the raw gas, and the filtration unit 420 is used to filter the raw gas.

[0044] Specifically, the cooling unit 410 is a water cooler, and the filtering unit 420 includes a gas-liquid separator 421 and a filter 422 that are connected, and the gas-liquid separator 421 is connected to the water cooler. The raw gas decomposed by carbonyl sulfide is cooled by the water cooler, and the water in the gas is reduced by the gas-liquid separator 421, and finally the raw gas is filtered by the filter 422 to remove impurities such as filler debris that may be generated in the process, and finally reaches the use condition of the gas end.

[0045] It should be noted that the purification components included in the embodiments of the present application are all existing technologies, and the components in the existing technology can be directly adopted, and their structures and principles will not be described in detail here.

[0046] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0047] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A raw gas deep purification system, characterized in that: Includes the following connected in sequence: Cleaning system, used to remove impurities from the raw gas; A low-temperature methanol washing system, used to remove acidic gases in the feed gas, the low-temperature methanol washing system comprising an absorption tower storing a methanol solution, the absorption tower having a liquid inlet and a liquid outlet; A decomposition system, used for decomposing the raw gas to generate hydrogen sulfide, the decomposition system comprises a mixing unit, a deoxygenation unit and a decomposition unit which are connected in sequence, the mixing unit is connected to the low-temperature methanol washing system, the decomposition unit is connected to the filtering system, wherein the decomposition unit comprises a thermostat and a carbonyl sulfide decomposer, the carbonyl sulfide decomposer is used for decomposing the raw gas to generate hydrogen sulfide; A filtration system is used to filter the raw gas.

2. The raw gas deep purification system according to claim 1, characterized in that: The cleaning system includes a connected impurity removal unit and a gas-liquid separation unit, the gas-liquid separation unit is connected to the low-temperature methanol washing system, the impurity removal unit is used to remove impurities in the raw gas, and the gas-liquid separation unit is used to remove free water in the raw gas.

3. The raw gas deep purification system according to claim 2, characterized in that: The impurity removal unit includes a water washing tower, a cooling tower and a decoking tower which are connected in sequence, the decoking tower is connected to the gas-liquid separation unit, the water washing tower is used to remove dust in the raw gas, the cooling tower is used to cool the raw gas, and the decoking tower is used to remove tar in the raw gas.

4. The raw gas deep purification system according to claim 2, characterized in that: The gas-liquid separation unit includes a buffer tank, a compression tank and a gas-liquid separation tank which are connected in sequence. The buffer tank is connected to the impurity removal unit, and the gas-liquid separation tank is connected to the low-temperature methanol washing system. The gas-liquid separation tank is used to remove free water in the raw gas.

5. The raw gas deep purification system according to claim 1, characterized in that: The mixing unit comprises a connected purified gas buffer tank and a gas mixing tank, the purified gas buffer tank is connected to the low-temperature methanol washing system, the gas mixing tank is connected to the deoxygenation unit, and the purified gas buffer tank is used to purify the raw gas.

6. The raw gas deep purification system according to claim 1, characterized in that: The deoxygenation unit includes a heat exchanger, a heater and a deoxygenation tower which are arranged in sequence. A circulation loop is formed among the heat exchanger, the heater and the deoxygenation tower, and the heat exchanger is connected to the mixing unit and the decomposition unit respectively. The heater is used to heat the raw gas, and the deoxygenation tower deoxygenates the raw gas.

7. The raw gas deep purification system according to any one of claims 1 to 4, characterized in that: The filtering system includes a cooling unit and a filtering unit. The cooling unit is connected to the decomposition system, and the filtering unit is connected to the gas using end. The cooling unit is used to cool the raw gas, and the filtering unit is used to filter the raw gas.

8. The raw gas deep purification system according to claim 7, characterized in that: The cooling unit is a water cooler, and the filtering unit includes a gas-liquid separator and a filter that are connected, and the gas-liquid separator is connected to the water cooler.

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