Hydrogen sulfide purification system and hydrogen sulfide purification method

Abstract

The invention belongs to the technical field of gas purification, and particularly relates to a hydrogen sulfide purification system and a hydrogen sulfide purification method. The hydrogen sulfide purification system comprises multi-stage pre-absorption towers connected in series and multi-stage absorption towers connected with the multi-stage pre-absorption towers, a gas outlet of the last-stage pre-absorption tower of the multi-stage pre-absorption towers is connected with a gas inlet of the first-stage absorption tower of the multi-stage absorption towers through a pipeline, and a valve is arranged on the pipeline; the liquid level of the absorption tower included in the multi-stage absorption tower is higher than that of the pre-absorption tower included in the multi-stage pre-absorption tower. The hydrogen sulfide purification system disclosed by the invention consists of the multi-stage pre-absorption tower and the multi-stage absorption tower which are connected in series, and is low in equipment investment, simple to operate and good in purification effect.

Description

Technical Field

[0001] The invention belongs to the technical field of gas purification, and in particular relates to a hydrogen sulfide purification system and a hydrogen sulfide purification method. Background Art

[0002] There are many methods for purifying hydrogen sulfide gas. The Chinese invention patent with publication number CN108392948A discloses a hydrogen sulfide purification process and device, which uses alumina, silica gel, zeolite, activated carbon and other molecular sieves to adsorb gas phase impurities to obtain a 99.5% hydrogen sulfide product. The Chinese invention patent with publication number CN105731496A discloses a method for producing sodium bicarbonate from acidic gas and purifying hydrogen sulfide, which uses sodium carbonate as a solution to absorb hydrogen sulfide in acidic gas to generate sodium hydrosulfide and sodium bicarbonate, and then flashes and decomposes sodium hydrosulfide to obtain hydrogen sulfide with a purity greater than 99%. A Chinese invention patent with publication number CN102153053A discloses a method for purifying methane to prepare hydrogen sulfide, a byproduct of carbon disulfide. The method mainly involves desulfurization and distillation to obtain a mixer containing hydrogen sulfide and carbon disulfide, which is then further compressed, cooled, and distilled to obtain hydrogen sulfide with a purity greater than 99%.

[0003] However, actual research has found that when the above-mentioned means are used to extract and purify the target product, not only is the purification process complicated and the investment cost high, but there is also the defect that the purity of the extracted product is not ideal. Summary of the invention

[0004] In view of the defects of the prior art, the present invention provides a hydrogen sulfide purification system and a hydrogen sulfide purification method.

[0005] Specifically, the present invention is achieved through the following technologies:

[0006] A hydrogen sulfide purification system, comprising:

[0007] A multi-stage pre-absorption tower connected in series and a multi-stage absorption tower connected to the multi-stage pre-absorption tower, wherein the air outlet of the last stage pre-absorption tower of the multi-stage pre-absorption tower is connected to the air inlet of the first stage absorption tower of the multi-stage absorption tower through a pipeline, and a valve is provided on the pipeline; the liquid level of the absorption tower included in the multi-stage absorption tower is higher than the liquid level of the pre-absorption tower included in the multi-stage pre-absorption tower.

[0008] The multi-stage pre-absorption tower comprises a first pre-absorption tower, a second pre-absorption tower, and a third pre-absorption tower; the multi-stage absorption tower comprises a first absorption tower and a second absorption tower.

[0009] The first pre-absorption tower, the second pre-absorption tower, the third pre-absorption tower, the first absorption tower and the second absorption tower all include a liquid inlet, an air inlet, a liquid outlet and an air outlet; wherein the liquid inlet, the air inlet and the liquid outlet are located below each device, and the air outlet is located at the top of each device;

[0010] The air inlet of the first pre-absorption tower is connected to the carbonized tail gas supply device through a pipeline; the air outlet of the first pre-absorption tower is connected to the air inlet of the second pre-absorption tower through a pipeline; the air outlet of the second pre-absorption tower is connected to the air inlet of the third pre-absorption tower through a pipeline; the air outlet of the third pre-absorption tower is connected to the air inlet of the first absorption tower through a pipeline; the air outlet of the first absorption tower is connected to the air inlet of the second absorption tower through a pipeline; the air outlet of the second absorption tower is connected to the hydrogen sulfide treatment system through a pipeline; the liquid inlets of the first pre-absorption tower, the second pre-absorption tower, the third pre-absorption tower, the first absorption tower and the second absorption tower are connected to the yellow water supply equipment through a pipeline, and the liquid outlets are connected to the material storage equipment through a pipeline; wherein, a valve is provided on each connecting pipeline.

[0011] A gas distributor is arranged above the gas inlet of the first absorption tower and the second absorption tower.

[0012] A steam inlet is provided at the bottom of the first absorption tower and the second absorption tower, and the steam inlet is connected to a steam supply device.

[0013] Another gas outlet is provided at the top of the multi-stage pre-absorption tower and the multi-stage absorption tower, and the other gas outlet is connected to the hydrogen sulfide treatment system through a pipeline.

[0014] A pre-buffer tank, a booster pump and a flow meter are sequentially arranged on the pipeline in front of the air inlet and the liquid inlet of the first pre-absorption tower along the material flow direction.

[0015] The booster pump is a plunger type booster pump.

[0016] On the other hand, the present invention provides a method for purifying hydrogen sulfide, which adopts the above-mentioned hydrogen sulfide purification system, comprising:

[0017] (1) Pumping yellow water into the multi-stage pre-absorption tower and the multi-stage absorption tower; wherein the liquid level of the multi-stage absorption tower is higher than the liquid level of the multi-stage pre-absorption tower;

[0018] (2) closing the valve between the air outlet of the last stage pre-absorption tower and the air inlet of the first stage absorption tower;

[0019] (3) introducing the carbonized tail gas into the multi-stage pre-absorption tower, controlling the pressure of the carbonized tail gas by a booster pump, and slowly opening the valve when the last stage pre-absorption tower is saturated with pre-carbonization, and discharging high-purity hydrogen sulfide gas when the last stage absorption tower reaches the end point of pre-carbonization.

[0020] In the above-mentioned method for purifying hydrogen sulfide, the introduction rate of the carbonized tail gas is 30-40 L / min, and the pressure is 0.1-0.3 MPa.

[0021] The technical solution of the present invention has the following beneficial effects:

[0022] (1) The hydrogen sulfide purification system of the present invention is composed of a multi-stage pre-absorption tower and a multi-stage absorption tower connected in series, with small equipment investment, simple operation and good purification effect;

[0023] (2) The hydrogen sulfide purification method of the present invention overcomes the defect that yellow water cannot absorb hydrogen sulfide to the pre-carbonization end point due to solubility and impurity carbon dioxide, by pre-carbonizing the carbonized tail gas under a certain pressure before entering the multi-stage absorption tower, thereby greatly improving the purification effect of hydrogen sulfide. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the following detailed description of the preferred embodiment.The drawings are only for the purpose of illustrating the preferred embodiments and are not to be construed as limiting the invention.

[0025] Figure 1 Schematic diagram of the structure of a hydrogen sulfide purification system used in one embodiment;

[0026] Figure 2 Schematic diagram of the structure of a hydrogen sulfide purification system used in yet another embodiment. DETAILED DESCRIPTION

[0027] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific embodiments. Except for the following contents, the process method of the present invention adopts conventional methods or devices in the art. Unless otherwise specified, the following terms have the meanings commonly understood by those skilled in the art.

[0028] The terms "first", "second", etc. used herein do not indicate any order or importance, but are used to distinguish one element from another. The terms "the", "said", "one", and "an" do not indicate a limitation of quantity, but indicate the presence of at least one of the objects mentioned. The terms "preferred", "more preferred", etc. refer to embodiments of the present invention that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. In addition, the description of one or more embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0029] In order to further promote product diversification research and development, carefully cultivate new economic growth points, and enhance the company's market competitiveness, the applicant intends to use the current carbonized acid gas (hydrogen sulfide) as one of the main raw materials to produce the downstream product sodium hydrosulfide, thereby reducing costs and improving economic benefits.

[0030] During the research and development process, the applicant found that one of the key factors for success is the need for high-purity hydrogen sulfide gas as a reaction raw material. However, combined with traditional carbonization conditions, the purity of acid gas in the carbonization production process is relatively low, containing 15-20% CO2, which has a serious impact on the production cost and product quality of downstream sulfur products.

[0031] According to the barium carbonate production principle (BaS+CO2+H2O→BaCO3↓+H2S↑), the relatively high-concentration acid gas at the carbonization tail is pressurized and then enters a designated series purification and absorption device, and the hydrogen sulfide is purified by a yellow water multi-stage absorption process technology, thereby overcoming the defect that the yellow water cannot absorb the hydrogen sulfide to the carbonization predetermined end point due to the solubility and impurity carbon dioxide, and greatly improving the purification effect of hydrogen sulfide.

[0032] Specifically, a hydrogen sulfide purification system of the present invention comprises: a multi-stage pre-absorption tower connected in series and a multi-stage absorption tower connected to the multi-stage pre-absorption tower, wherein the gas outlet of the last stage pre-absorption tower of the multi-stage pre-absorption tower is connected to the gas inlet of the first stage absorption tower of the multi-stage absorption tower through a pipeline, and a valve is provided on the pipeline; the liquid level of the absorption tower included in the multi-stage absorption tower is higher than the liquid level of the pre-absorption tower included in the multi-stage pre-absorption tower.

[0033] Setting the liquid level in the absorption tower higher than that in the pre-absorption tower can effectively increase the gas-liquid contact area and reaction time in the absorption tower, which is beneficial to improving the absorption effect of the small amount of carbon dioxide contained in hydrogen sulfide and achieving the desired purification effect.

[0034] Among them, the number of pre-absorption towers connected in series in the multi-stage pre-absorption tower is more than 3; the number of absorption towers connected in series in the multi-stage absorption tower is more than 2.

[0035] In some preferred embodiments, Figure 1 As shown, the hydrogen sulfide purification system 10 of the present invention comprises a first pre-absorption tower 1, a second pre-absorption tower 2, a third pre-absorption tower 3, a first absorption tower 4 and a second absorption tower 5 which are connected in series in sequence.

[0036] Wherein, the first pre-absorption tower 1, the second pre-absorption tower 2, the third pre-absorption tower 3, the first absorption tower 4 and the second absorption tower 5 all include a liquid inlet, an air inlet, a liquid outlet and an air outlet; wherein, the liquid inlet, the air inlet and the liquid outlet are located at the bottom of each device, and the air outlet is located at the top of each device.

[0037] Wherein, the air inlet of the first pre-absorption tower 1 is connected to the carbonized tail gas supply device 6 through a pipeline; the air outlet of the first pre-absorption tower 1 is connected to the air inlet of the second pre-absorption tower 2 through a pipeline; the air outlet of the second pre-absorption tower 2 is connected to the air inlet of the third pre-absorption tower 3 through a pipeline; the air outlet of the third pre-absorption tower 3 is connected to the air inlet of the first absorption tower 4 through a pipeline; the air outlet of the first absorption tower 4 is connected to the air inlet of the second absorption tower 5 through a pipeline; the air outlet of the second absorption tower 5 is connected to the hydrogen sulfide treatment system 7 through a pipeline; the liquid inlets of the first pre-absorption tower 1, the second pre-absorption tower 2, the third pre-absorption tower 3, the first absorption tower 4 and the second absorption tower 5 are connected to the yellow water supply equipment 8 through a pipeline, and the liquid outlets are connected to the material storage equipment 9 through a pipeline; wherein, a valve is provided on each connecting pipeline.

[0038] In some preferred embodiments, the pre-absorption tower is a liquid separation tank with specifications of: Φ0.8m*2m, V 容积 =1m 3 .

[0039] Among them, the volume of yellow water in the pre-absorption tower shall be based on the overflow pipe scale.

[0040] In some preferred embodiments, the absorption tower is made of Φ219*4mm stainless steel pipe and has a total height of 5m.

[0041] In some preferred embodiments, a gas distributor is disposed above the gas inlet of the first absorption tower 4 and the second absorption tower 5 to promote uniform gas distribution and promote gas-liquid contact reaction.

[0042] In some preferred embodiments, in order to avoid the blockage of yellow water crystals caused by low temperature and ensure the smooth progress of the experiment, the present invention provides a steam inlet at the bottom of the first absorption tower 4 and the second absorption tower 5. The steam inlet is connected to a steam supply device (not shown).

[0043] In some preferred embodiments, Figure 2 As shown, another gas outlet is provided at the top of the multi-stage pre-absorption tower and the multi-stage absorption tower, and the other gas outlet is connected to the hydrogen sulfide treatment system 7 through a pipeline.

[0044] The present invention provides another gas outlet to facilitate the exhaustion of hydrogen sulfide gas in the tower during equipment failure or maintenance.

[0045] In some preferred embodiments, a pre-buffer tank (not shown), a booster pump (not shown) and a flow meter (not shown) are sequentially arranged on the pipeline in front of the air inlet and the liquid inlet of the first pre-absorption tower along the material flow direction.

[0046] The present invention can overcome the gas volume fluctuation factor by arranging the front buffer tank and the flow meter, so that the carbonized tail gas enters the pre-absorption tower at a stable rate.

[0047] The inventor found in the experiment that H2S and CO2 were released simultaneously after the H2S tail gas was absorbed by the second, third and fourth stages, and the highest H2S concentration was only 66.44%, indicating incomplete CO2 absorption. The results of the BaS content test of yellow water showed that: under low pressure conditions, when CO2 and H2S gases coexist, it is difficult for yellow water to absorb H2S gas to saturation. At this time, the selective absorption capacity of yellow water is weak, and the reaction rate is slow. After analysis, the inventor reached the following conclusion: the system pressure has a great influence on the gas-liquid absorption reaction. The test pressure is too low, which reduces the gas solubility, resulting in the yellow water absorbing H2S to fail to reach saturation, and the yellow water absorbing H2S fails to reach the carbonization pre-end point.

[0048] The present invention provides a booster pump to complete pre-carbonization of the carbonized tail gas under a certain pressure before entering the multi-stage absorption tower, thereby overcoming the defect that yellow water cannot absorb hydrogen sulfide to the pre-carbonization end point due to solubility and impurity carbon dioxide, and greatly improving the purification effect of hydrogen sulfide.

[0049] Further preferably, the booster pump used in the present invention is a plunger booster pump, which can be purchased from Jinan Simingte Technology Co., Ltd. The maximum gas volume of the plunger booster pump is 108L / min, and the rated pressure is adjustable within the range of 0.4-1Mpa.

[0050] In some optional embodiments, the yellow water feed pipe and the H2S intake pipe use the same pipe, thereby simplifying the equipment and reducing investment costs.

[0051] On the other hand, the present invention also provides a method for purifying hydrogen sulfide, which adopts the above-mentioned hydrogen sulfide purification system, comprising:

[0052] (1) Pumping yellow water into the multi-stage pre-absorption tower and the multi-stage absorption tower; wherein the liquid level of the multi-stage absorption tower is higher than the liquid level of the multi-stage pre-absorption tower;

[0053] (2) closing the valve between the air outlet of the last stage pre-absorption tower and the air inlet of the first stage absorption tower;

[0054] (3) introducing the carbonized tail gas into the multi-stage pre-absorption tower, controlling the pressure of the carbonized tail gas by a booster pump, and slowly opening the valve when the last stage pre-absorption tower is saturated with pre-carbonization, and discharging high-purity hydrogen sulfide gas when the last stage absorption tower reaches the end point of pre-carbonization.

[0055] After pre-carbonization and saturation, it enters the multi-stage absorption tower for absorption. At this time, the barium sulfide solution in the multi-stage absorption tower only absorbs carbon dioxide and no longer absorbs hydrogen sulfide, creating conditions for obtaining high-purity hydrogen sulfide in a short time and improving the test efficiency.

[0056] In some preferred embodiments, before using the hydrogen sulfide purification system of the present invention, the booster pump needs to be tested for air tightness to ensure normal operation and the instrument is sensitive and reliable.

[0057] In some preferred embodiments, the introduction rate of the carbonized tail gas is 30-40 L / min, and the pressure is 0.1-0.3 MPa.

[0058] In a preferred embodiment, the hydrogen sulfide purification system used in the present invention comprises a first pre-absorption tower 1, a second pre-absorption tower 2, a third pre-absorption tower 3, a first absorption tower 4 and a second absorption tower 5 connected in series. The first absorption tower 4 and the second absorption tower 5 are Φ219 pipelines with a total height of 5m and a liquid level of 4m. The total liquid level height of the first pre-absorption tower 1, the second pre-absorption tower 2, the third pre-absorption tower 3, the first absorption tower 4 and the second absorption tower 5 is about 12.5m.

[0059] According to the method of the present invention, the carbonized tail gas can be purified to a dry hydrogen sulfide concentration of ≧99.5%, and the average concentration of carbon dioxide after absorption is stable at ≦0.1%. The sodium carbonate index in the sodium hydrosulfide product obtained by using the purified hydrogen sulfide of the present invention as a raw material is far lower than the national standard requirement, which proves the feasibility of the purification process of the present invention.

[0060] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods without specific conditions in the following examples are based on conventional methods and conditions.

[0061] use Figure 1 The hydrogen sulfide purification system shown is used to purify carbonized tail gas, wherein a pre-buffer tank, a booster pump and a flow meter are sequentially arranged on the pipeline along the material flow direction in front of the air inlet and the liquid inlet of the first pre-absorption tower.

[0062] (1) Before use, perform an air tightness test on the H2S booster pump to ensure that it operates normally and the instrument is sensitive and reliable.

[0063] (2) Connect the booster pump to the test process to ensure that it meets the process design requirements.

[0064] (3) Check whether all preparatory work, including process flow, safety, environmental protection, and operability, is ready.

[0065] (4) The yellow water feed pipe and the H2S intake pipe use the same pipe to pump yellow water into the first pre-absorption tower, the second pre-absorption tower, the third pre-absorption tower, the first absorption tower, and the second absorption tower respectively. The concentration of yellow water is 120-130g / L; the volume of yellow water in the first pre-absorption tower, the second pre-absorption tower, and the third pre-absorption tower is 0.7m 3 , the liquid level is 0.8m; the volume of yellow water in the first absorption tower 4 and the second absorption tower is 0.17m 3 , the liquid level is 4.5m.

[0066] (5) Start the booster pump to deliver carbonized tail gas at a delivery rate of 30-40 L / min. Detect the carbonized tail gas composition multiple times. The test data are shown in Table 1. Pay attention to adjusting the pump outlet pressure, close the valve between the third pre-absorption tower and the first absorption tower, and allow the carbonized tail gas to enter the first pre-absorption tower, the second pre-absorption tower, and the third pre-absorption tower in turn.

[0067] Table 1 Carbonized exhaust gas detection data

[0068] 1st time 2nd 3rd 4th <![CDATA[H2S%]]> 48.73％ 45.44％ 69.72％ 52.01％ <![CDATA[CO2%]]> 25.27％ 25.27％ 12.47％ 12.90％

[0069] (6) As time goes by, the system pressure rises slowly, and the yellow water pre-carbonization of the first pre-absorption tower, the second pre-absorption tower, and the third pre-absorption tower is saturated in turn. After it is detected that the pre-carbonization of the third pre-absorption tower has reached the end point, the H2S valve between the third pre-absorption tower and the first absorption tower is slowly opened to allow the gas to enter the first absorption tower and the second absorption tower. The carbonization changes of the first absorption tower and the second absorption tower are continuously tracked and detected. When the pre-carbonization of the second absorption tower reaches the end point, high-purity hydrogen sulfide gas is discharged. After multiple sampling and analysis, the average CO2 concentration in the high-purity hydrogen sulfide gas is 0.0179%.

[0070] The present invention has been disclosed above with preferred embodiments, but those skilled in the art should understand that these embodiments are only used to describe the present invention and should not be understood as limiting the scope of the present invention. It should be noted that all changes and substitutions equivalent to these embodiments should be deemed to be included in the scope of the claims of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined in the claims.

Claims

1. A hydrogen sulfide purification system, characterized in that: include: A multi-stage pre-absorption tower connected in series and a multi-stage absorption tower connected to the multi-stage pre-absorption tower, wherein the air outlet of the last stage pre-absorption tower of the multi-stage pre-absorption tower is connected to the air inlet of the first stage absorption tower of the multi-stage absorption tower through a pipeline, and a valve is provided on the pipeline; the liquid level of the absorption tower included in the multi-stage absorption tower is higher than the liquid level of the pre-absorption tower included in the multi-stage pre-absorption tower.

2. The hydrogen sulfide purification system according to claim 1, characterized in that: The multi-stage pre-absorption tower comprises a first pre-absorption tower, a second pre-absorption tower, and a third pre-absorption tower; the multi-stage absorption tower comprises a first absorption tower and a second absorption tower.

3. The hydrogen sulfide purification system according to claim 2, characterized in that: The first pre-absorption tower, the second pre-absorption tower, the third pre-absorption tower, the first absorption tower and the second absorption tower all include a liquid inlet, an air inlet, a liquid outlet and an air outlet; wherein the liquid inlet, the air inlet and the liquid outlet are located below each device, and the air outlet is located at the top of each device; The air inlet of the first pre-absorption tower is connected to the carbonized tail gas supply device through a pipeline; the air outlet of the first pre-absorption tower is connected to the air inlet of the second pre-absorption tower through a pipeline; the air outlet of the second pre-absorption tower is connected to the air inlet of the third pre-absorption tower through a pipeline; the air outlet of the third pre-absorption tower is connected to the air inlet of the first absorption tower through a pipeline; the air outlet of the first absorption tower is connected to the air inlet of the second absorption tower through a pipeline; the air outlet of the second absorption tower is connected to the hydrogen sulfide treatment system through a pipeline; the liquid inlets of the first pre-absorption tower, the second pre-absorption tower, the third pre-absorption tower, the first absorption tower and the second absorption tower are connected to the yellow water supply equipment through a pipeline, and the liquid outlets are connected to the material storage equipment through a pipeline; wherein, a valve is provided on each connecting pipeline.

4. The hydrogen sulfide purification system according to claim 3, characterized in that: A gas distributor is arranged above the gas inlet of the first absorption tower and the second absorption tower.

5. The hydrogen sulfide purification system according to claim 3, characterized in that: A steam inlet is provided at the bottom of the first absorption tower and the second absorption tower, and the steam inlet is connected to a steam supply device.

6. The hydrogen sulfide purification system according to claim 2, characterized in that: Another gas outlet is provided at the top of the multi-stage pre-absorption tower and the multi-stage absorption tower, and the other gas outlet is connected to the hydrogen sulfide treatment system through a pipeline.

7. The hydrogen sulfide purification system according to claim 2, characterized in that: A pre-buffer tank, a booster pump and a flow meter are sequentially arranged on the pipeline in front of the air inlet and the liquid inlet of the first pre-absorption tower along the material flow direction.

8. The hydrogen sulfide purification system according to claim 7, characterized in that: The booster pump is a plunger type booster pump.

9. A method for purifying hydrogen sulfide, characterized in that: The hydrogen sulfide purification system according to any one of claims 1 to 8 comprises: (1) Pumping yellow water into the multi-stage pre-absorption tower and the multi-stage absorption tower; wherein the liquid level of the multi-stage absorption tower is higher than the liquid level of the multi-stage pre-absorption tower; (2) closing the valve between the air outlet of the last stage pre-absorption tower and the air inlet of the first stage absorption tower; (3) introducing the carbonized tail gas into the multi-stage pre-absorption tower, controlling the pressure of the carbonized tail gas by a booster pump, and slowly opening the valve when the last stage pre-absorption tower is saturated with pre-carbonization, and discharging high-purity hydrogen sulfide gas when the last stage absorption tower reaches the end point of pre-carbonization.

10. The method for purifying hydrogen sulfide according to claim 9, characterized in that: The introduction rate of the carbonized tail gas is 30-40 L / min, and the pressure is 0.1-0.3 MPa.

Images