Hydrogen sulfide adsorption method, hydrogen sulfide adsorption apparatus, and hydrogen gas production method using the hydrogen sulfide adsorption method.

Abstract

The objective is to provide a hydrogen sulfide adsorption method that is inexpensive, has excellent hydrogen sulfide adsorption capacity, and allows for continuous adsorption over long periods of time. A further problem that the present invention aims to solve is to provide a hydrogen sulfide adsorption apparatus for realizing the hydrogen sulfide adsorption method and a hydrogen gas production method using the hydrogen sulfide adsorption method. [Solution] The hydrogen sulfide adsorption method includes a first step of obtaining a first gas by passing a hydrogen sulfide-containing gas through a first adsorption section filled with a neutralizing precipitate having hydrogen sulfide adsorption capacity, and a second step of obtaining a second gas by passing the first gas through a second adsorption section filled with a hydrogen sulfide gas adsorbent.

Description

Technical Field

[0001] The present invention relates to a hydrogen sulfide adsorption method, a hydrogen sulfide adsorption device, and a hydrogen gas production method using the hydrogen sulfide adsorption method.

Background Art

[0002] Conventionally, as a method for adsorbing hydrogen sulfide, an adsorption method using a hydrogen storage alloy or other adsorbent substances is known. However, in the method using a hydrogen storage alloy, since rare metals such as rare earth elements are used, there are economic problems such as an increase in equipment costs, and there are also problems from the perspective of environmental load.

[0003] In addition to hydrogen storage alloys, there is also a method of using iron oxide or the like as an adsorbent substance, but it has not been possible to comprehensively cope with various hydrogen sulfide gases. Therefore, by using a combination of several types of materials, it is possible to cope with various hydrogen sulfide gases, and an increase in the size of the apparatus and an increase in processing costs have been inevitable.

[0004] In order to solve these problems, in Patent Document 1, it has been proposed to use a desulfurizer containing a neutralization precipitate obtained by neutralizing mine wastewater discharged from a mine as a raw material. On the other hand, from the viewpoint of realizing a system with low environmental load and high energy efficiency, a proposal has been made in recent years to use a fuel cell using hydrogen gas derived from biomass raw materials.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, since these neutralized sediments used as adsorbents are natural materials, it was not possible to accurately predict the breakthrough time of the adsorption capacity, and there was a problem that the purified gas discharged from the outlet may contain hydrogen sulfide. Furthermore, when using fuel cells, if hydrogen sulfide from the biomass raw materials remains in the hydrogen gas ultimately used, the power generation performance of the fuel cell will decrease, which can lead to problems such as an increase in the amount of hydrogen used and the need to increase the amount of metal catalyst used in the fuel cell.

[0007] The problem that the present invention aims to solve is to provide a hydrogen sulfide adsorption method that is inexpensive, has excellent hydrogen sulfide adsorption capacity, and allows for continuous adsorption over a long period of time, by using a neutralized precipitate having hydrogen sulfide adsorption capacity in the flow path of a hydrogen sulfide-containing gas. A further problem that the present invention aims to solve is to provide a hydrogen sulfide adsorption apparatus for realizing the hydrogen sulfide adsorption method and a hydrogen gas production method using the hydrogen sulfide adsorption method. [Means for solving the problem]

[0008] As a result of diligent research to solve the above problems, the inventors conceived of passing hydrogen sulfide-containing gas through a neutralizing precipitate and then adsorbing the hydrogen sulfide onto a hydrogen sulfide gas adsorbent. The gist of the hydrogen sulfide adsorption method, hydrogen sulfide adsorption apparatus, and hydrogen gas production method using the hydrogen sulfide adsorption method of the present invention is as follows.

[0009] [1] A first step is to obtain a first gas by passing a hydrogen sulfide-containing gas through a first adsorption section filled with a neutralized precipitate having hydrogen sulfide adsorption capacity, A second step involves obtaining a second gas by passing the first gas through a second adsorption section filled with a hydrogen sulfide gas adsorbent, A method for adsorbing hydrogen sulfide, including the following. [2] A measurement step, which is performed after the first step and before the second step, in which the hydrogen sulfide concentration of the first gas is measured, A hydrogen sulfide adsorption method according to [1], further comprising a neutralization sediment exchange step of exchanging the neutralization sediment based on the hydrogen sulfide concentration measured in the measurement step. [3] A measurement step, which is performed after the first step and before the second step, in which the hydrogen sulfide concentration of the first gas is measured, A hydrogen sulfide adsorption method according to [1] or [2], further comprising a prediction step of predicting the breakthrough time of the hydrogen sulfide gas adsorbent based on the history of hydrogen sulfide concentrations measured in the measurement step. [4] The hydrogen sulfide adsorption method according to any one of [1] to [3], wherein the neutralized sediment is a neutralized sediment obtained by neutralizing mine wastewater. [5] The hydrogen sulfide adsorption method according to [4], wherein the temperature of the first adsorption section in the first step is 150°C or higher. [6] The hydrogen sulfide gas adsorbent is LaNi5, as described in any of [1] to [5]. [7] The hydrogen sulfide adsorption method according to [6], wherein the temperature of the second adsorption section in the second step is 200°C or higher. [8] A first adsorption section comprising a neutralizing precipitate having hydrogen sulfide adsorption capacity, A second adsorption section is located downstream of the first adsorption section and is equipped with a hydrogen sulfide gas adsorbent, A hydrogen sulfide adsorption device having the following features. [9] The hydrogen sulfide adsorption apparatus according to [8], further comprising a gas measuring section downstream of the first adsorption section and upstream of the second adsorption section. A method for producing hydrogen gas, comprising adsorbing hydrogen sulfide from biomass-derived gas using the hydrogen sulfide adsorption method described in any of [1] to [7]

[10] . [Effects of the Invention]

[0010] According to the present invention, by using a neutralized precipitate having hydrogen sulfide adsorption capacity, it is possible to provide a hydrogen sulfide adsorption method that is inexpensive, has excellent hydrogen sulfide adsorption capacity, and allows for continuous adsorption over a long period of time in a flow path of hydrogen sulfide-containing gas. Furthermore, it is possible to provide a hydrogen sulfide adsorption apparatus for realizing this hydrogen sulfide adsorption method and a hydrogen gas production method using this hydrogen sulfide adsorption method. [Brief explanation of the drawing]

[0011] [Figure 1] It is a schematic diagram of the hydrogen sulfide adsorption device according to this embodiment. [Figure 2A] It is a graph showing the breakthrough curve of the neutral precipitate when a hydrogen sulfide-containing gas is passed through the hydrogen sulfide adsorption device according to this embodiment. [Figure 2B] It is a graph showing the breakthrough curve of the hydrogen sulfide gas adsorbent when a hydrogen sulfide-containing gas is passed through the hydrogen sulfide adsorption device according to this embodiment. [Figure 3] It is a flowchart of the hydrogen sulfide adsorption method according to this embodiment.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail. However, the present invention is not limited to the following description and can be variously modified and implemented within the scope of the gist.

[0013] [Definitions] Prior to the description of the embodiments according to the present invention, the neutral precipitate, the hydrogen sulfide gas adsorbent, and the breakthrough time in this specification will be described.

[0014] - Neutral precipitate having hydrogen sulfide adsorption ability - In this specification, the neutral precipitate having hydrogen sulfide adsorption ability is obtained by neutralizing mine wastewater. Typically, the one flowing out from the mine tunnels of abandoned mines can be used. Examples of mine wastewater include an iron salt aqueous solution containing iron ions and reduced inorganic sulfur compounds that exhibits acidity with a pH of 4 or less due to oxidation. By adding an alkali to this acidic mine wastewater, a neutral precipitate in which components containing a large amount of iron oxide contained in the mine wastewater are precipitated is obtained. Some neutral precipitates contain schwertmannite and goethite as secondary minerals, and these have particularly excellent hydrogen sulfide adsorption ability. When representing the constituent chemical components in the form of oxides, it is composed of ferric oxide (Fe2O3), aluminum oxide (Al2O3), silicon dioxide (SiO2), calcium oxide (CaO), sulfur trioxide (SO3), zinc oxide (ZnO), etc. Note that mine wastewater means all the groundwater flowing out to the surface from abandoned mines or operating mines where the mining of underground resources has ended. In the present invention, the mine wastewater of abandoned mines is used from the viewpoint of obtaining the neutral precipitate at a low cost.

[0015] - Hydrogen Sulfide Gas Adsorbent - In this specification, the hydrogen sulfide gas adsorbent is an adsorbent that physically or chemically adsorbs hydrogen sulfide gas. Also, in the present embodiment, when referring to the "hydrogen sulfide gas adsorbent", it refers to something that can accurately estimate the adsorption ability and predict the breakthrough time, and does not include the above-mentioned neutral precipitate. Specifically, it refers to hydrogen storage alloys such as Mg2Ni, CaNi5, LaNi5, MnNi 4.5 Al 0.5 and other metal intermetallic compounds and oxides such as iron oxide, iron hydroxide, and zinc oxide.

[0016] - Breakthrough Time - In this specification, breakthrough time refers to the time required when using a hydrogen sulfide adsorption device, from the start of flowing hydrogen sulfide-containing gas until hydrogen sulfide leaks out at the outlet (downstream of the adsorption section equipped with the neutralized sediment or hydrogen sulfide gas adsorbent) in an amount exceeding a certain permissible limit. In preliminary experiments, breakthrough time refers to the point at which the hydrogen sulfide concentration in the exhaust gas of the neutralized sediment exceeds 1.0 ppm, while in a hydrogen sulfide adsorption device simulating practical use, it refers to the point at which the hydrogen sulfide concentration in the exhaust gas exceeds 0.1 ppm.

[0017] Prior to describing this embodiment, the following preliminary experiments were conducted to confirm the breakthrough time of the hydrogen sulfide gas adsorbent and the neutralizing precipitate used for hydrogen sulfide adsorption, as well as the change in hydrogen sulfide concentration in the exhaust gas over time.

[0018] (Preliminary experiment) First, in order to confirm the properties of the neutralized precipitate as an adsorbent, Experimental Examples 1-9 were conducted under the following conditions, and the time to breakthrough conditions was confirmed when hydrogen sulfide-containing gas was adsorbed.

[0019] <Test Conditions> • Hydrogen sulfide gas composition: H2S = 196 ppm (H2 = balance) • Hydrogen sulfide gas flow rate: 20 ml / min • Breakthrough condition: In Experimental Examples 1-6, the breakthrough condition was when the hydrogen sulfide concentration in the exhaust gas exceeded 1.0 ppm, and in Experimental Examples 7-9, the breakthrough condition was when the concentration exceeded 0.1 ppm. -Neutralized sediment- • Sample temperature: 40℃~250℃ ·Filling amount: 0.2000g ·Particle size: 1.00mm~2.36mm

[0020] The measurement results are shown in Table 1 below.

[0021] [Table 1]

[0022] In preliminary experiments, the sample temperature was sequentially changed from 40°C to 250°C in Experiments 1-6. The results showed that the adsorption capacity of neutralized sediment is temperature-dependent, with higher temperatures tending to exhibit better adsorption capacity. Furthermore, the time to breakthrough was confirmed three times under the same conditions as Experiment 6, except that the breakthrough condition was set to 0.1 ppm (Experiments 7-9). These results indicate that when neutralized sediment is used as an adsorbent, even with standardized temperature conditions, there is variability in breakthrough time, making it difficult to accurately predict the breakthrough time.

[0023] (Examples) Next, as shown in Figure 1, neutralized sediment 30 was placed in the preceding first adsorption section 10, similar to the preliminary experiment. Then, LaNi5 was placed in the subsequent second adsorption section 20 as a hydrogen sulfide gas adsorbent 50, and the breakthrough time for each adsorbent was confirmed from the residual hydrogen sulfide concentration results from the gas measurement section 61 and gas measurement section 62. Here, assuming actual usage conditions, the residual hydrogen sulfide concentration used to determine the breakthrough time was set to 0.1 ppm. The sample temperature of the neutralized sediment 30 measured at the thermometer side section 71 was set to 250°C, which yielded the best results in the preliminary experiment. The test conditions are shown below.

[0024] <Test Conditions> • Hydrogen sulfide gas composition: H2S = 196 ppm (H2 = balance) • Hydrogen sulfide gas flow rate: 20 ml / min • Breakthrough condition: When the hydrogen sulfide concentration in the exhaust gas exceeds 0.1 ppm. -Neutralized sediment (first adsorption part)- • Sample temperature: 250℃ ·Filling amount: 0.2000g ·Particle size: 1.00mm~2.36mm ―LaNi5 (Second Adsorption Layer)― • Sample temperature: 250℃ ·Filling amount: 0.2000g ·Particle size: 1.59mm or less

[0025] In this example, after the neutralized sediment 30 reached breakthrough, that is, after the hydrogen sulfide concentration directly below the neutralized sediment exceeded 0.1 ppm, the hydrogen sulfide-containing gas was continued to flow until the subsequent hydrogen sulfide gas adsorbent 50 broke through. The hydrogen sulfide concentrations were measured in the gas measurement section 61 directly below the neutralized sediment and the gas measurement section 62 directly below the hydrogen sulfide gas adsorbent, and their history (breakthrough curves) was obtained. The obtained breakthrough curves for the neutralized sediment and hydrogen sulfide gas adsorbent are shown in Figures 2A and 2B.

[0026] (Reference example) Furthermore, the breakthrough time when only LaNi5 was used as the adsorbent in the first adsorption portion under the same temperature conditions as the example was used as a reference example.

[0027] The measurement results are shown in Table 2 below.

[0028] [Table 2]

[0029] Table 2 shows that in the example where LaNi5 was placed as the sulfur gas adsorbent 50 in the second adsorption section 20, the neutralized precipitate alone broke through in 8349.2 minutes, but the hydrogen sulfide concentration at the outlet gas of the second adsorption section measured in the gas measurement section 62 remained below 0.1 ppm until 10952.2 minutes. This indicates that hydrogen gas without hydrogen sulfide could be supplied for 2603 minutes even after the neutralized precipitate broke through. According to the reference example, the breakthrough time for LaNi5 alone was 687.8 minutes, whereas in the multi-stage configuration of the example, the time equivalent to the breakthrough time for LaNi5 alone was 2603 minutes. From this fact, it can be confirmed that in the configuration of this example, the LaNi5 in the second adsorption section exhibits hydrogen sulfide gas adsorption function for approximately 3 to 4 times longer than the LaNi5 in the reference example. The reason why the breakthrough time for LaNi5 alone is extended in this embodiment is that the amount of hydrogen sulfide gas supplied to LaNi5 is suppressed by the neutralization precipitate in the preceding step, thereby extending the lifespan of LaNi5.

[0030] These results show that, in the present invention, by using a neutralizing precipitate having hydrogen sulfide adsorption capacity and a hydrogen sulfide gas adsorbent (LaNi5 in the example) whose breakthrough time can be estimated in combination, the breakthrough time of the hydrogen sulfide adsorption device can be predicted and its lifespan can be significantly extended.

[0031] (Hydrogen sulfide adsorption method) Based on the preliminary experimental results described above, the hydrogen sulfide adsorption method according to an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described below with reference to the drawings. The hydrogen sulfide adsorption method according to this embodiment includes at least a first step and a second step. Details of each step will be described below.

[0032] <1st process> First, in the first step, a first gas is obtained by passing a hydrogen sulfide-containing gas through a first adsorption section filled with a neutralized sediment having hydrogen sulfide adsorption capacity. Here, it is preferable that the neutralized sediment having hydrogen sulfide adsorption capacity is a neutralized sediment obtained by neutralizing mine wastewater. This is because it has excellent hydrogen sulfide adsorption capacity due to its high content of iron hydroxide such as goethite, is inexpensive, and is an effective use of resources from the perspective of industrial waste reuse. Furthermore, when using a neutralized sediment obtained by neutralizing mine wastewater, the temperature of the neutralized sediment when used as an adsorbent is preferably 150°C or higher, more preferably 200°C or higher, and even more preferably 250°C or higher. This is because the hydrogen sulfide adsorption mechanism of the neutralized sediment is chemiadsorption, and the higher the temperature above a certain level, the more easily the chemical reaction proceeds.

[0033] <Second process> In the second step, the first gas is passed through a second adsorption section, which is filled with a hydrogen sulfide gas adsorbent after the first step, to obtain the second gas. Here, if a hydrogen sulfide gas adsorbent with a known hydrogen sulfide gas adsorption capacity is not used, the breakthrough time of the adsorbent in the second adsorption section cannot be predicted, and therefore residual hydrogen sulfide cannot be reliably removed. The type of hydrogen sulfide gas adsorbent is not limited, but it is preferable to use LaNi5. This is because the adsorption capacity can be accurately predicted and it functions even at relatively low temperatures. Furthermore, when using LaNi5 as the hydrogen sulfide gas adsorbent, the temperature of LaNi5 is preferably 200°C or higher, more preferably 250°C or higher, and even more preferably 300°C or higher. This is because below 200°C, LaNi5 does not have the ability to release hydrogen, and in the temperature range of 200°C or higher, the higher the temperature, the more hydrogen is released and only hydrogen selectively permeates.

[0034] <Measurement process> Furthermore, it is preferable to have a measurement step after the first step and before the second step to measure the hydrogen sulfide concentration of the first gas. Any measuring device can be used to measure the hydrogen sulfide concentration; for example, a gas chromatograph can be used. Based on the results obtained in the measurement step, a neutralization sediment exchange step and a prediction step can be carried out, and each of these steps will be described in detail below.

[0035] <<Neutralization precipitate exchange process>> In the hydrogen sulfide adsorption method according to this embodiment, it is preferable to have a neutralized sediment exchange step in which the neutralized sediment is exchanged based on the hydrogen sulfide concentration measured in the measurement step. Furthermore, from the viewpoint of minimizing the impact on the second adsorption section, it is preferable to use the point when the hydrogen sulfide concentration in the measurement step exceeds 1 ppm as the criterion for deciding whether to exchange the sediment. By providing this step, even if the neutralized sediment alone has broken through until the hydrogen sulfide gas adsorbent in the second adsorption section breaks through, only the neutralized sediment can be exchanged, and no hydrogen sulfide remains in the final exhaust gas (second gas).

[0036] <<Forecasting Process>> In the hydrogen sulfide adsorption method according to this embodiment, it is preferable to have a prediction step that predicts the breakthrough time of the hydrogen sulfide gas adsorbent based on the history of hydrogen sulfide concentration measured in the measurement step. By providing this step, even if the neutralized sediment alone has broken through, the breakthrough time of the hydrogen sulfide gas adsorbent can be accurately predicted from the cumulative hydrogen sulfide concentration measured after the first step and before the second step, so that no hydrogen sulfide remains in the final exhaust gas (second gas).

[0037] Furthermore, the neutralization sediment exchange process and prediction process, which include the measurement process described above, can be used individually, but they can also be used in combination in a more suitable configuration. Details will be explained below with reference to Figure 3.

[0038] In other words, it is preferable to further include, after the first step S10 and before the second step S50, a measurement step S20 for measuring the hydrogen sulfide concentration of the first gas, a neutralization precipitate exchange step S30 for exchanging the neutralization precipitate based on the hydrogen sulfide concentration measured in the measurement step S20, and a prediction step S40 for predicting the breakthrough time of the hydrogen sulfide gas adsorbent based on the history of the hydrogen sulfide concentration measured in the measurement step S20.

[0039] Here, since the measurement step S20, which continuously measures the hydrogen sulfide concentration of the first gas before and after the exchange, is continued, even if the neutralization sediment exchange step S30 is performed multiple times, the prediction step S40 can continue to accurately predict the breakthrough time of the hydrogen sulfide gas adsorbent. Therefore, in the hydrogen sulfide adsorption method according to the present invention, by combining the neutralization sediment exchange step and the prediction step, the hydrogen sulfide gas adsorbent can be reliably replaced before breakthrough, and the adsorption of hydrogen sulfide-containing gas can be continued, thereby achieving a longer lifespan for the hydrogen sulfide adsorption device without leaving hydrogen sulfide in the outlet gas (second gas).

[0040] By using the hydrogen sulfide adsorption method described above, hydrogen sulfide contained in biomass-derived hydrogen sulfide gas, such as biogas obtained from methane fermentation, can be adsorbed to obtain high-purity hydrogen gas. In particular, since biomass-derived gas can be used as hydrogen gas for fuel cell power generation, a system with a low environmental impact and high energy efficiency can be realized.

[0041] (Hydrogen sulfide adsorption device) The hydrogen sulfide adsorption method described above can be carried out using the hydrogen sulfide adsorption apparatus described in detail below. The hydrogen sulfide adsorption apparatus according to the present invention has at least a first adsorption section and a second adsorption section, and will be described in detail below with reference to Figure 1.

[0042] <1st suction part> The first adsorption section 10 is equipped with a neutralized sediment 30 having hydrogen sulfide adsorption capacity. As described above, the neutralized sediment is preferably obtained by neutralizing mine wastewater, and can be filled inside any sintered filter 41. The temperature of the neutralized sediment 30 stored in the first adsorption section 10 can be measured by a temperature measuring section 71, such as a thermocouple, which may be provided at the bottom of the sample section.

[0043] <Second suction part> The second adsorption section 20 is located downstream of the first adsorption section 10 and is equipped with a hydrogen sulfide gas adsorbent 50. The hydrogen sulfide gas adsorbent 50 is not particularly limited, but is preferably LaNi5 as described above, and can be packed inside any sintered filter 42. The temperature of the hydrogen sulfide gas adsorbent 50 stored in the second adsorption section 20 can be measured by a temperature measuring section 72, such as a thermocouple, which may be provided at the bottom of the sample section.

[0044] Furthermore, the hydrogen sulfide adsorption device preferably has a gas measuring unit 61 located downstream of the first adsorption unit 10 and upstream of the second adsorption unit 20. By having this gas measuring unit 61, the concentration of residual hydrogen sulfide in the gas that has passed through the first adsorption unit 10 can be confirmed, and a breakthrough curve can be obtained to predict the breakthrough time of the second adsorption unit 20. Although not essential, the device may further have an exhaust gas measuring unit 62 that has passed through the second adsorption unit 20 to detect whether the final exhaust gas contains hydrogen sulfide.

[0045] Here, in order to replace the neutralized sediment 30 at an appropriate time, it is preferable that the gas measuring unit 61 has a first notification means that issues an alarm when the measured hydrogen sulfide concentration reaches a specified concentration. Furthermore, it is preferable that the gas measuring unit 61 has a second notification means that issues an alarm when the breakthrough time of the hydrogen sulfide gas adsorbent 50 is reached based on the history of the measured hydrogen sulfide concentration. [Industrial applicability]

[0046] As described above, by using a neutralized precipitate with hydrogen sulfide adsorption capacity in the flow path of hydrogen sulfide-containing gas, it is possible to provide a hydrogen sulfide adsorption method that is inexpensive, has excellent hydrogen sulfide adsorption capacity, and allows for continuous adsorption over a long period of time. Furthermore, it is possible to provide a hydrogen sulfide adsorption apparatus for realizing this hydrogen sulfide adsorption method and a hydrogen gas production method using this hydrogen sulfide adsorption method.

[0047] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of this invention is considered to be a technology that can contribute to "No. 7: Affordable and Clean Energy" and "No. 12: Responsible Consumption and Production," among others. [Explanation of symbols]

[0048] 10 1st adsorption part 20 Second suction part 30 Neutralized sediment 41, 42 Sintered filters 50 Hydrogen sulfide gas adsorbent 61, 62 Gas measurement section 71, 72 Temperature measurement section

Claims

1. A first step involves obtaining a first gas by passing a hydrogen sulfide-containing gas through a first adsorption section filled with a neutralized precipitate having hydrogen sulfide adsorption capacity, A second step involves obtaining a second gas by passing the first gas through a second adsorption section filled with a hydrogen sulfide gas adsorbent, A method for adsorbing hydrogen sulfide, including the following.

2. A measurement step, which is performed after the first step and before the second step, to measure the hydrogen sulfide concentration of the first gas, The hydrogen sulfide adsorption method according to claim 1, further comprising a neutralization sediment exchange step of exchanging the neutralization sediment based on the hydrogen sulfide concentration measured in the measurement step.

3. A measurement step, which is performed after the first step and before the second step, to measure the hydrogen sulfide concentration of the first gas, The hydrogen sulfide adsorption method according to claim 1, further comprising a prediction step of predicting the breakthrough time of the hydrogen sulfide gas adsorbent based on the history of hydrogen sulfide concentration measured in the measurement step.

4. The hydrogen sulfide adsorption method according to claim 1, wherein the neutralized sediment is a neutralized sediment obtained by neutralizing mine wastewater.

5. The hydrogen sulfide adsorption method according to claim 4, wherein the temperature of the first adsorption section in the first step is 150°C or higher.

6. The hydrogen sulfide gas adsorbent is LaNi ５ The hydrogen sulfide adsorption method according to claim 1.

7. The hydrogen sulfide adsorption method according to claim 6, wherein the temperature of the second adsorption section in the second step is 200°C or higher.

8. A first adsorption section comprising a neutralizing precipitate having hydrogen sulfide adsorption capacity, A second adsorption section is located downstream of the first adsorption section and is equipped with a hydrogen sulfide gas adsorbent, A hydrogen sulfide adsorption device having the following features.

9. The hydrogen sulfide adsorption apparatus according to claim 8, further comprising a gas measuring unit located downstream of the first adsorption unit and upstream of the second adsorption unit.

10. A method for producing hydrogen gas, comprising adsorbing hydrogen sulfide from a biomass-derived gas using the hydrogen sulfide adsorption method described in claim 1 to obtain hydrogen gas.

Images