Algae hydrogen production device, waste gas purification method and algae hydrogen production method

Abstract

The invention discloses an algae hydrogen production device, and discloses a waste gas purification method applied to waste gas purification in the algae hydrogen production device and an algae hydrogen production method applied to algae hydrogen production in the algae hydrogen production device. The waste gas purification and algae hydrogen production device comprises a waste gas inlet, a desulfurization device, a water separator, a first adsorption tower, a hydrolysis tower, a second adsorption tower and a culture tank, the waste gas inlet is communicated with an external waste gas outlet, the desulfurization device is used for removing sulfur elements in waste gas, and the water separator is used for removing water in the waste gas transmitted from an exhaust port of the desulfurization device; the first adsorption tower is used for adsorbing particle solid impurities in the waste gas transmitted from the exhaust port of the water separator, the hydrolysis tower is used for decomposing macromolecular organic matters in the waste gas transmitted from the first adsorption tower, and the second adsorption tower is used for adsorbing water in the waste gas transmitted from the hydrolysis tower; the culture tank is used for culturing hydrogen-producing algae and producing hydrogen by using input raw material gas.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection, and in particular to an algae hydrogen production device, an exhaust gas purification method, and an algae hydrogen production method. Background Art

[0002] With the current development of industry, waste gas is generated in various industrial activities. These waste gases often contain harmful substances that can directly or indirectly harm the environment and biological health. In particular, sulfur compounds are generated in many industrial productions, including but not limited to SO2, H2S, SO3 and some sulfur-containing organic matter. Most of these chemicals will directly or indirectly pollute the environment and harm biological health, which will result in the waste gas needing to be treated before it can be discharged into the atmosphere.

[0003] As a clean energy source, hydrogen can not only be used in the energy field, but also as a catalyst and industrial raw material in many industrial production activities. Currently, most hydrogen is obtained from artificial production. In the artificial production of hydrogen, the mainstream is mainly water electrolysis and fossil fuel reforming. These two methods are not only inefficient, but also cause energy waste and potential environmental pollution. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an algae hydrogen production device that can purify harmful substances in exhaust gas and use the purified exhaust gas as feed gas for algae hydrogen production.

[0005] The present invention also proposes a waste gas purification method applied to the algae hydrogen production device.

[0006] The present invention also proposes an algae hydrogen production method applied to the algae hydrogen production device.

[0007] According to an embodiment of the first aspect of the present invention, an algae hydrogen production device includes: a waste gas inlet, a desulfurization device, a water separator, a first adsorption tower, a hydrolysis tower, a second adsorption tower and a culture tank, wherein the waste gas inlet is connected to the external waste gas outlet; the air inlet of the desulfurization device is connected to the waste gas inlet, and the desulfurization device is used to remove sulfur elements in the waste gas; the air inlet of the water separator is connected to the exhaust port of the desulfurization device, and the water separator is used to remove water in the waste gas transmitted from the exhaust port of the desulfurization device; the air inlet of the first adsorption tower is connected to the exhaust port of the water separator, and the first adsorption tower is used to remove water from ... for adsorbing particulate solid impurities in the waste gas transmitted from the exhaust port of the water separator; the air inlet of the hydrolysis tower is connected to the exhaust port of the first adsorption tower, and the hydrolysis tower is used to decompose the macromolecular organic matter in the waste gas transmitted from the first adsorption tower; the air inlet of the second adsorption tower is connected to the exhaust port of the hydrolysis tower, and the second adsorption tower is used to adsorb water in the waste gas transmitted from the hydrolysis tower; the air inlet of the culture tank is connected to the exhaust port of the second adsorption tower, and the exhaust port of the culture tank is connected to the hydrogen collection box, and the culture tank is used to cultivate hydrogen-producing algae and produce hydrogen using the input raw gas.

[0008] It has at least the following beneficial effects: the waste gas inlet is used to connect to the external waste gas outlet to receive the waste gas into the device; the desulfurization device is used to remove sulfur-containing compounds in the waste gas, including inorganic sulfur-containing compounds and organic sulfur-containing compounds; the water separator is used to remove moisture in the waste gas to prevent the moisture in the waste gas from affecting subsequent waste gas purification; the first adsorption tower is used to adsorb particulate solids in the waste gas; the hydrolysis tower is used to decompose large molecular organic impurities; the second adsorption tower is used to adsorb residual moisture in the waste gas; the culture tank is loaded with water and hydrogen-producing algae; the culture tank is used to provide a place for hydrogen-producing algae to produce hydrogen through photosynthesis.

[0009] According to some embodiments of the present invention, the bottom end of the water separator is connected to a first drainage pipe, and the first drainage pipe is used to drain water in the water separator.

[0010] According to some embodiments of the present invention, a water storage tank is further included, wherein a water inlet of the water storage tank is connected to the first drainage pipe, and the water storage tank is used to store water flowing out of the water separator.

[0011] According to some embodiments of the present invention, a second drainage pipe is connected to the lower side of the water storage tank, and a water outlet of the second drainage pipe is connected to the culture tank.

[0012] According to some embodiments of the present invention, a booster is further included, wherein the air inlet of the booster is connected to the exhaust port of the first adsorption tower, and the exhaust port of the booster is connected to the air inlet of the hydrolysis tower, and the booster is used to pressurize the gas in the pipeline.

[0013] According to some embodiments of the present invention, the device further comprises a heat exchanger, which is disposed outside the pipeline between the hydrolysis tower and the second adsorption tower, and is used to cool the gas in the pipeline.

[0014] According to some embodiments of the present invention, the culture tank is provided with several, several of the culture tank air inlets are connected in parallel and connected to the exhaust port of the second adsorption tower, and several of the culture tank air outlets are connected in parallel and connected to the hydrogen collection box.

[0015] According to some embodiments of the present invention, the tops of several of the culture tanks are connected to hydrogen exhaust pipes, several of the hydrogen exhaust pipes are connected in parallel and connected to the hydrogen collection box, and each of the hydrogen exhaust pipes is provided with a one-way hydrogen output valve, which is used to control the output of hydrogen in one direction.

[0016] A waste gas purification method according to a second embodiment of the present invention, applied to the algae hydrogen production device of the first embodiment, comprises the following steps: S1, after the exhaust gas enters this device, it first passes through the desulfurization device, where the sulfur element in the exhaust gas is removed through alkaline absorption and oxidation absorption; S2, the desulfurized waste gas passes through the water separator, and the water separator removes water from the waste gas; S3, the exhaust gas after the water is removed by the water separator passes through the first adsorption tower to remove the particulate solids in the exhaust gas; S4, the waste gas after the granular solids are removed from the first adsorption tower passes through the hydrolysis tower to remove macromolecular organic matter in the waste gas; S5, the gas after the macromolecular organic matter is removed from the hydrolysis tower passes through the second adsorption tower to remove water in the waste gas. After the above steps, the waste gas can be purified into raw gas that can be directly used for algae hydrogen production.

[0017] At least the following beneficial effects are achieved: This waste gas purification method has all the beneficial effects brought about by the above-mentioned algae hydrogen production device, which will not be repeated here.

[0018] A method for producing hydrogen from algae according to a third embodiment of the present invention, applied to the algae hydrogen production device of the first embodiment, includes the following steps: S1, placing water and hydrogen-producing algae in the culture tank, and maintaining negative pressure in the culture tank; S2, maintaining sunlight or light irradiation on the hydrogen-producing algae in the culture tank for 12 hours, so that the hydrogen-producing algae in the culture tank continuously perform photosynthesis and the bioaccumulation amount of the hydrogen-producing algae reaches a predetermined level; S3, filling the hydrogen-producing algae culture tank in the culture tank with a raw gas at a pressure of 0.15 MPa, and replacing all the gas in the hydrogen-producing algae culture tank with the raw gas within 45 seconds, and exhausting the original gas in the culture tank through the replacement air pipe, and then stopping the injection of raw gas, so that the hydrogen-producing algae can achieve hydrogen conversion in a sulfur-free and oxygen-free environment, and the one-way hydrogen output valve of the culture tank outputs hydrogen in one direction; S4, replacing the raw gas in the culture tank every 3 hours.

[0019] At least the following beneficial effects are achieved: This algae hydrogen production method has all the beneficial effects brought about by the above-mentioned algae hydrogen production device, which will not be repeated here.

[0020] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 Schematic diagram of the structure of an embodiment of the present invention; Figure Numbers: Figure Numbers: Exhaust gas inlet 100; Desulfurization device 200; Water separator 300, first drainage pipe 310; First adsorption tower 400; hydrolysis tower 500; Second adsorption tower 600; Culture tank 700, hydrogen exhaust pipe 710, one-way hydrogen output valve 711, second drainage pipe 720, replacement air pipe 730; Hydrogen collection box 800; Booster 900a, heat exchanger 900b, water storage tank 900c. DETAILED DESCRIPTION

[0022] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0023] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0024] Reference Figure 1The present invention discloses an algae hydrogen production device, including: a waste gas inlet 100, a desulfurization device 200, a water separator 300, a first adsorption tower 400, a hydrolysis tower 500, a second adsorption tower 600 and a culture tank 700.

[0025] The waste gas inlet 100 is connected to the external waste gas outlet, and the waste gas inlet 100 is used to receive the waste gas and introduce the waste gas into the algae hydrogen production device.

[0026] The desulfurization device 200 has an air inlet connected to the exhaust gas inlet 100. The desulfurization device 200 is used to remove sulfur elements in the exhaust gas. The desulfurization device 200 adopts a method combining alkaline absorption and oxidative absorption to remove inorganic sulfur-containing compounds such as SO2 and H2S in the exhaust gas. At the same time, it also removes sulfur-containing organic matter in the exhaust gas, effectively removing sulfur elements in the exhaust gas. It can be understood that the replaced sulfur elements can be reduced to sulfur elements and reused in industrial production. This process is a common technology in this field and will not be elaborated in detail.

[0027] The water separator 300 has an air inlet connected to the exhaust port of the desulfurization device 200. The water separator 300 is used to remove water from the exhaust gas transmitted from the exhaust port of the desulfurization device 200. When the exhaust gas passes through the desulfurization device 200, it carries a large amount of water due to the large amount of heat and the fast gas flow rate. The water separator 300 can not only effectively remove the water in the exhaust gas, but also adjust the flow rate and flow of the gas.

[0028] The first adsorption tower 400 has an air inlet connected to the exhaust port of the water separator 300. The first adsorption tower 400 is used to adsorb particulate solid impurities in the exhaust gas transmitted from the exhaust port of the water separator 300. Activated carbon material is provided in the first adsorption tower 400, which can effectively adsorb solid impurities in the exhaust gas. It is understandable that the first adsorption tower 400 can also be set to electrostatic adsorption or chemical adsorption designed according to the chemical properties of the solid particles, such as active sites (such as acidic sites of zeolite molecular sieves) forming stable compounds with heavy metal particles (Pb / Cd).

[0029] The hydrolysis tower 500 has an air inlet connected to the exhaust port of the first adsorption tower 400. The hydrolysis tower 500 is used to decompose the macromolecular organic matter in the exhaust gas transmitted from the first adsorption tower 400. The hydrolysis tower 500 decomposes the macromolecular organic matter into small molecular monomers through a hydrolysis reaction. Among them, toxic ester / amide compounds can be decomposed by breaking chemical bonds, and difficult-to-degrade substances such as plasticizers can also be hydrolyzed under high temperature and high pressure conditions.

[0030] The second adsorption tower 600 has an air inlet connected to the exhaust port of the hydrolysis tower 500. The second adsorption tower 600 is used to adsorb water in the exhaust gas transmitted from the hydrolysis tower 500. The culture tank 700 has an air inlet connected to the exhaust port of the second adsorption tower 600, and the exhaust port of the culture tank 700 is connected to the hydrogen collection box 800. The culture tank 700 is used to cultivate hydrogen-producing algae and produce hydrogen using the input raw gas.

[0031] In some embodiments, the bottom end of the water separator 300 is connected to a first drainage pipe 310, which is used to drain the water in the water separator 300. A valve is provided on the first drainage pipe 310. When the water in the water separator 300 accumulates to a certain amount, the valve is opened to drain the water accumulated in the water separator 300. The first drainage pipe 310 is a conventional setting in this field and will not be elaborated in detail.

[0032] In some embodiments, the device also includes a water tank 900c, the water inlet of the water tank 900c is connected to the first drainage pipe 310, and the water tank 900c is used to store water flowing out of the water separator 300. It can be understood that a water purification system should be provided in the water tank 900c, which is used to purify the water flowing from the water separator 300. The purified water can be kept for standby to achieve the recycling of water resources.

[0033] In some embodiments, the lower side of the water storage tank 900c is connected to a second drainage pipe 720, the water outlet of the second drainage pipe 720 is connected to the culture tank 700, one end of the second drainage pipe 720 is connected to the water storage tank 900c, and the other end of the second drainage pipe 720 is connected to the culture tank 700. The second drainage pipe 720 is used to discharge the purified water in the water storage tank 900c to the culture tank 700 as raw water for algae hydrogen production. It can be understood that a valve is provided on the second drainage pipe 720, which is used to control the connection or cutoff of the second drainage pipe 720.

[0034] In some embodiments, a booster 900a is further included, the air inlet of the booster 900a is connected to the exhaust port of the first adsorption tower 400, and the exhaust port of the booster 900a is connected to the air inlet of the hydrolysis tower 500. The booster 900a is used to pressurize the gas in the pipeline.

[0035] It can be understood that the algae hydrogen production device also includes a booster 900a, the air inlet of the booster 900a is connected to the exhaust port of the first adsorption tower 400, and the exhaust port of the booster 900a is connected to the air inlet of the hydrolysis tower 500. The booster 900a is used to pressurize the gas in the pipeline, and the booster 900a is used to drive the waste gas in the pipeline forward. The power of the booster 900a can be adjusted according to the actual gas flow of the waste gas to be treated and the raw gas demand for hydrogen production.

[0036] It should be noted that the algae hydrogen production device also includes a heat exchanger 900b, which is arranged on the outside of the pipeline between the hydrolysis tower 500 and the second adsorption tower 600. The heat exchanger 900b is used to cool the gas in the pipeline. Since the algae hydrogen production device usually directly uses the newly discharged exhaust gas as the raw gas, the gas temperature is relatively high, which is not conducive to the survival temperature of the hydrogen-producing algae and the catalytic temperature of the hydrogenase in the subsequent algae hydrogen production, the exhaust gas needs to be cooled.

[0037] It should be noted that there are several culture tanks 700, and several culture tanks 700 are connected in parallel and the gas outlets are connected to the hydrogen collection box 800. Several culture tanks 700 can increase the hydrogen production efficiency, thereby increasing the demand for waste gas, thereby increasing the waste gas purification efficiency. Several culture tanks 700 can ensure that when one or several culture tanks 700 fail to produce hydrogen, other culture tanks 700 can continue to produce hydrogen, ensuring the continuity of the waste gas purification process and the hydrogen production process. It can be understood that several culture tanks 700 can be set into two groups for alternating work. There are several second drainage pipes 720, and several drainage pipes are connected in parallel to the water tank 900c. The number of second drainage pipes 720 is the same as the number of culture tanks 700, and one second drainage pipe 720 is connected to one culture tank 700.

[0038] In some embodiments, a hydrogen exhaust pipe 710 is provided on the top of several culture tanks 700, and a one-way hydrogen output valve 711 is provided on each hydrogen exhaust pipe 710. The one-way hydrogen output valve 711 is used to control the one-way output of hydrogen. The one-way hydrogen output valve 711 ensures that only hydrogen can flow from the culture tank 700 into the hydrogen collection box 800 in one direction, thereby obtaining pure hydrogen, which can be directly stored or used without further purification. The one-way hydrogen output valve 711 is a valve that outputs hydrogen in one direction. It uses pressure difference and anti-backflow device to ensure that hydrogen can only flow out of the culture tank 700. The one-way hydrogen output valve 711 is a commonly used technology in this field and will not be described in detail here.

[0039] According to the second aspect of the present invention, a waste gas purification method is applied to the waste gas purification part of the algae hydrogen production device, comprising the following steps: ① After the exhaust gas enters this device, it first passes through the desulfurization device 200 to remove the sulfur element in the exhaust gas through alkaline absorption and oxidation absorption; ② The desulfurized waste gas passes through the water separator 300 to remove water from the waste gas; ③ After the water is removed from the waste gas by the water separator 300, it passes through the first adsorption tower 400 to remove the particulate solids in the waste gas; ④ After the granular solids are removed from the exhaust gas in the first adsorption tower 400, the exhaust gas passes through the hydrolysis tower 500 to remove the macromolecular organic matter in the exhaust gas; ⑤ After the large molecular organic matter is removed from the hydrolysis tower 500, the gas passes through the second adsorption tower 600 to remove water from the waste gas; After the above steps, the waste gas can be purified into raw gas that can be directly used for algae hydrogen production.

[0040] The above has described a method for purifying waste gas from the algae-based hydrogen production device, which will not be elaborated on here.

[0041] According to a third aspect of the present invention, a method for producing hydrogen from algae, which is applied to the algae hydrogen production part of the exhaust gas purification in the algae hydrogen production device, comprises the following steps: ① Place water and hydrogen-producing algae in the culture tank 700 and maintain negative pressure in the culture tank 700; ② Maintaining 12 hours of sunlight or light exposure to the hydrogen-producing algae in the culture tank 700, so that the hydrogen-producing algae in the culture tank 700 can continue to photosynthesize and the bioaccumulation of the hydrogen-producing algae can reach a high level; S3, the hydrogen-producing algae culture tank 700 is filled with raw gas at a pressure of 0.15 MPa, and the gas in the hydrogen-producing algae culture tank 700 is completely replaced by the raw gas within 45 seconds. The original gas in the culture tank 700 is discharged through the replacement gas pipe 730, and then the injection of raw gas is stopped, so that the hydrogen-producing algae can achieve hydrogen conversion in a sulfur-free and oxygen-free environment. The one-way hydrogen output valve 711 of the culture tank 700 outputs hydrogen in a one-way manner; ④ Replace the oxygen in the culture tank 700 every three hours.

[0042] After the above steps, algae can be used to efficiently produce hydrogen.

[0043] In the above-mentioned algae hydrogen production method, the hydrogen-producing algae used is cyanobacteria, which can also be replaced by hydrogen-producing algae among green algae or diatoms. It can be understood that during the culture stage, water and cyanobacteria are placed in the culture tank 700, and then the negative pressure in the culture tank 700 is maintained to effectively prevent the inside of the culture tank 700 from being contaminated by other bacteria or particulate matter. Subsequently, the cyanobacteria in the culture tank 700 are exposed to sunlight or light for 12-15 hours, during which the cyanobacteria biomass accumulates to a certain level, which is sufficient for the subsequent algae hydrogen production process. In preparation, when the cyanobacteria biomass accumulates to a certain level, the gas in the original culture tank 700 can be replaced within 45 seconds with raw gas at a pressure of 0.15 MPa. At this time, the culture tank 700 remains sulfur-free and oxygen-free, which can ensure that hydrogenase efficiently catalyzes hydrogen production. At this time, the one-way hydrogen output valve 711 is opened to start hydrogen production. Since cyanobacteria will produce hydrogen during photosynthesis, the culture tank 700 needs to be gas-replaced every three hours to ensure that the oxygen content in the culture tank 700 is always kept at a low level.

[0044] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] Of course, the present invention is not limited to the above-mentioned embodiments. Those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An algae hydrogen production device, characterized in that: include: An exhaust gas inlet (100) is connected to an external exhaust gas outlet; a desulfurization device (200), the air inlet of which is connected to the exhaust gas inlet (100), and the desulfurization device (200) is used to remove sulfur from the exhaust gas; a water separator (300), the air inlet of which is connected to the exhaust port of the desulfurization device (200), and the water separator (300) is used to remove water from the exhaust gas transmitted from the exhaust port of the desulfurization device (200); a first adsorption tower (400), the air inlet of which is connected to the exhaust port of the water separator (300), and the first adsorption tower (400) is used to adsorb particulate solid impurities in the exhaust gas transmitted from the exhaust port of the water separator (300); a hydrolysis tower (500), the air inlet of which is connected to the exhaust port of the first adsorption tower (400), and the hydrolysis tower (500) is used to decompose macromolecular organic matter in the waste gas transmitted from the first adsorption tower (400); A second adsorption tower (600), the air inlet of which is connected to the exhaust port of the hydrolysis tower (500), and the second adsorption tower (600) is used to adsorb water in the waste gas transmitted from the hydrolysis tower (500); The culture tank (700) has an air inlet connected to the exhaust port of the second adsorption tower (600), and the exhaust port of the culture tank (700) is connected to the hydrogen collection box (800). The culture tank (700) is used to cultivate hydrogen-producing algae and produce hydrogen using the input raw gas.

2. The algae hydrogen production device according to claim 1, characterized in that: The bottom end of the water separator (300) is connected to a first drainage pipe (310), and the first drainage pipe (310) is used to drain water from the water separator (300).

3. The algae hydrogen production device according to claim 2, characterized in that: It also includes a water storage tank (900c), the water inlet of the water storage tank (900c) is in communication with the first drainage pipe (310), and the water storage tank (900c) is used to store water flowing out of the water separator (300).

4. The algae hydrogen production device according to claim 3, characterized in that: The lower side of the water storage tank (900c) is connected to a second drainage pipe (720), and the water outlet of the second drainage pipe (720) is connected to the culture tank (700).

5. The algae hydrogen production device according to claim 1, characterized in that: It also includes a booster (900a), the air inlet of the booster (900a) is connected to the exhaust port of the first adsorption tower (400), and the exhaust port of the booster (900a) is connected to the air inlet of the hydrolysis tower (500), and the booster (900a) is used to pressurize the gas in the pipeline.

6. The algae hydrogen production device according to claim 1, characterized in that: It also includes a heat exchanger (900b), which is arranged outside the pipeline between the hydrolysis tower (500) and the second adsorption tower (600), and is used to cool the gas in the pipeline.

7. The algae hydrogen production device according to claim 1, characterized in that: The culture tank (700) is provided with several air inlets of the culture tank (700) connected in parallel and connected to the exhaust port of the second adsorption tower (600), and several air outlets of the culture tank (700) are connected in parallel and connected to the hydrogen collection box (800).

8. The algae hydrogen production device according to claim 7, characterized in that: The tops of several of the culture tanks (700) are connected to hydrogen exhaust pipes (710), and several of the hydrogen exhaust pipes (710) are connected in parallel and connected to the hydrogen collection box (800). Each of the hydrogen exhaust pipes (710) is provided with a one-way hydrogen output valve (711), and the one-way hydrogen output valve (711) is used to control the output of hydrogen in one direction.

9. A method for purifying waste gas, characterized in that: An algae hydrogen production device according to any one of claims 1 to 8 is used, comprising the following steps: S1, after the exhaust gas enters the device, it first passes through the desulfurization device (200), and the sulfur element in the exhaust gas is removed by alkaline absorption and oxidation absorption in the desulfurization device (200); S2, the desulfurized waste gas passes through the water separator (300), and the water separator (300) removes water from the waste gas; S3, the waste gas after the water is removed by the water separator (300) passes through the first adsorption tower (400), and the granular solids in the waste gas are removed; S4, the waste gas after the granular solids are removed by the first adsorption tower (400) passes through the hydrolysis tower (500) to remove macromolecular organic matter in the waste gas; S5, the gas after the macromolecular organic matter is removed from the hydrolysis tower (500) passes through the second adsorption tower (600) to remove water from the waste gas. After the above steps, the waste gas can be purified into raw gas that can be directly used for algae hydrogen production.

10. A method for producing hydrogen from algae, characterized in that: The method for purifying waste gas according to claim 9 is applied to the raw gas produced, comprising the following steps: S1, placing water and hydrogen-producing algae in the culture tank (700), and maintaining a negative pressure in the culture tank (700); S2, maintaining sunlight or light irradiation on the hydrogen-producing algae in the culture tank (700) for 12 hours, so that the hydrogen-producing algae in the culture tank (700) can continue to photosynthesize, and the bioaccumulation amount of the hydrogen-producing algae can reach a predetermined level; S3, charging the hydrogen-producing algae culture tank (700) in the culture tank (700) with a raw gas at a pressure of 0.15 MPa, replacing all the gas in the hydrogen-producing algae culture tank (700) with the raw gas within 45 seconds, and discharging the original gas in the culture tank (700) through the replacement gas pipe (730), and then stopping the injection of the raw gas, so that the hydrogen-producing algae can achieve hydrogen conversion in a sulfur-free and oxygen-free environment, and the one-way hydrogen output valve (711) of the culture tank (700) outputs hydrogen in a one-way manner; S4, replacing the raw gas in the culture tank (700) once every 3 hours.

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