A method for treating a hydrogen sulfide-containing tail gas based on microalgae

Abstract

The application provides a method for treating hydrogen sulfide-containing tail gas based on microalgae, and relates to a technology for converting hydrogen sulfide into solid microalgae biomass by utilizing the photosynthesis capacity of microalgae, so as to remove hydrogen sulfide. The technology comprises the following steps: feeding the tail gas containing hydrogen sulfide into a reactor, converting the hydrogen sulfide into microalgae biomass by utilizing the absorption, accumulation, conversion and photosynthesis mechanisms of specific microalgae, generating nutrients and energy, providing sufficient oxygen and light source through an aeration system, and adjusting the temperature, ORP, PH value and other conditions in the reactor to promote the growth and metabolism of microalgae. Finally, the purpose of removing hydrogen sulfide is achieved by collecting and processing the microalgae. The method provided by the application has the advantages of high desulfurization efficiency, low treatment cost and simple operation, and can be widely applied to the treatment of sulfur-containing tail gas, resource recovery and other fields.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gas purification, and particularly relates to a method for treating hydrogen sulfide-containing tail gas based on microalgae. BACKGROUND

[0002] Air pollution and atmospheric pollutants have become a serious problem in public health and environmental protection. Hydrogen sulfide is a toxic and harmful gas that poses a serious threat to human, animal and plant health and the environment. It is widely present in industries that produce waste gas, such as sewage treatment plants, chemical plants and food processing plants. Traditional methods for removing hydrogen sulfide include chemical methods, physical methods and biological methods. Among them, the chemical method mainly uses oxidizing agents, reducing agents and absorbents and other chemical reagents to remove hydrogen sulfide. This method has the problems of high cost, complex operation and secondary pollution. The physical method mainly uses adsorption, absorption and other physical processes to remove hydrogen sulfide. Although this method is more environmentally friendly than the chemical method, it has lower efficiency. The biological method uses the ability of microorganisms to metabolize hydrogen sulfide to remove hydrogen sulfide, and has the advantages of low cost, high efficiency, simple operation and environmental protection. However, the current method for removing hydrogen sulfide using microorganisms has the defects of slow growth rate of microorganisms and sensitivity of strains to environmental conditions. Therefore, it is of great significance to develop a new desulfurization technology that is efficient, economical and environmentally friendly.

[0003] Microalgae are a group of microscopic single-cell organisms that can only be distinguished under a microscope. They are the lowest autotrophic aquatic organisms and are widely distributed in various water bodies in nature, including oceans, freshwater, ponds and rivers. Microalgae play an important role in the entire global ecosystem. As the largest solar assimilator in the ecological circle, microalgae provide more than 50% of the primary productivity and oxygen to the earth with less than 1% of the biomass of higher plants. They are the highest-efficiency photosynthetic organisms.

[0004] There are many types of bioenergy that can be developed and sourced from a wide range of sources. Among the many raw materials for producing bioenergy, microalgae have the advantages of high photosynthetic efficiency, fast growth rate, high oil content, non-arable land occupation, waste water and waste gas cultivation, and year-round production, making them a typical representative of the third generation of bioenergy. They can be used to produce healthy food, cosmetics, medicine, biofuels and other products. In addition, microalgae can also be used for biological adsorption, water treatment and environmental purification.

[0005] At present, microalgae is only one of the tools for biological carbon sequestration and removal of other harmful gases, however, in recent years, the energy crisis has become increasingly prominent. Therefore, the use of microalgae resources to help solve the environmental and energy problems at the same time has attracted much attention. The microalgae desulfurization technology is still in the research stage, and the technology for removing hydrogen sulfide by using microalgae is less, and is mainly applied to the purification of biogas. Meier et al. used chlorella to purify biogas, completely removed the hydrogen sulfide gas in the biogas, and found that there was a high dissolved oxygen condition in the system and the final oxidation product of sulfide was sulfate. Prandini et al. used microalgae to remove 3000 ppm of hydrogen sulfide under autotrophic conditions. Unlike sulfur-oxidizing bacteria, the hydrogen sulfide removal process of microalgae can be attributed to direct assimilation and oxidation, and hydrogen sulfide is mainly oxidized to sulfide, thiosulfate and sulfite in the microalgae system, and then these sulfur oxides are further oxidized by oxygen to generate sulfate, and serve as the main sulfur source for the assimilation process of microalgae. The above results prove that microalgae have the potential to remove hydrogen sulfide.

[0006] The microalgae desulfurization technology is one of the hotspots of current research, and is still in the stage of continuous research and development and improvement. Compared with the traditional chemical absorption and biological desulfurization method, the microalgae desulfurization technology has the advantages of low cost, low energy consumption, long service life, no secondary pollution, etc., and has broad application prospect and very important significance. SUMMARY

[0007] The present application aims at the problems and deficiencies in the prior art, and provides a method for utilizing the photosynthesis and unique metabolic function of microalgae to realize the treatment of gas containing hydrogen sulfide under simple and efficient conditions, so as to achieve the purpose of removing harmful gas. Specifically, specific microalgae are selected, and the culture environment of the microalgae and the contact conditions of hydrogen sulfide are optimized, so that the microalgae have the ability to realize efficient desulfurization. The microalgae produce oxygen and other organic matter through photosynthesis, and utilize the metabolic function of the microalgae to react hydrogen sulfide with oxygen to form harmless substances such as sulfur, sulfate and water.

[0008] Therefore, the first aspect of the present application provides a method for treating tail gas containing hydrogen sulfide based on microalgae, and the process generally includes an absorption reactor, a photobioreactor, a microalgae aeration system, a circulation system and the like.

[0009] According to the method provided by the present application, the microalgae treatment of tail gas containing hydrogen sulfide mainly includes the following steps:

[0010] S1: The pre-processed tail gas containing hydrogen sulfide is sent to the input end of the first reactor, the input end of the second reactor is connected with the output end of the first reactor, and the output end of the second reactor is connected with the tail gas discharge;

[0011] S2: The microalgae desulfurization solution enters the liquid distributor from the upper part of the first reactor and the second reactor, is uniformly sprayed in the reactor, fully contacts with the hydrogen sulfide-containing tail gas to absorb hydrogen sulfide, and is discharged from the bottom;

[0012] S3: The discharged microalgae desulfurization solution is pumped into the heater and then enters the microalgae light reactor, the light source is adjusted to promote the photosynthesis of microalgae to produce nutrients and energy, and part of the sulfide in the liquid is converted into solid microalgae biomass;

[0013] S4: The solution flowing out of the light reactor enters the microalgae aeration reactor, air is introduced through the aeration system, and the temperature, ORP, DO, pH value and other conditions in the reactor are adjusted to promote the catalysis of sulfide by enzymes in the microalgae cells, reaction metabolism, generation of sulfur element and sulfate, and thus sulfur conversion;

[0014] S5: The solution of the microalgae reactor is pumped into the first reactor and the second reactor for recycling.

[0015] In the present application: the first reactor and the second reactor can be used in series, or can be used alone.

[0016] In the present application: the microalgae light reactor body is generally made of machine glass material or transparent plastic film, and the reactor structure can be flat plate type, column type, pipe type, conical type and other light bioreactor types with different sizes.

[0017] In the present application: the light source used in the microalgae light reactor selects white light or natural light between 400-700 nm,

[0018] The illumination time is 6-18h.

[0019] In the present application: the temperature in the microalgae light reactor and the microalgae aeration reactor is adjusted to 15-35℃.

[0020] In the present application: the pH value in the microalgae light reactor and the microalgae aeration reactor is adjusted to 6.0-8.5.

[0021] In the present application: the ORP in the microalgae light reactor and the microalgae aeration reactor is adjusted to-500--200ev.

[0022] In the present application: the DO value in the microalgae light reactor and the microalgae aeration reactor is adjusted to 2-10 mg / L.

[0023] In the present application: one of sodium carbonate or potassium carbonate is added in the microalgae desulfurization solution, and the concentration is 0.5-10 g / L.

[0024] In the present application: the density of microalgae in the microalgae desulfurization solution is 0.1-2.0 g / L.

[0025] In this invention: the ORP value of the microalgae aeration reactor is interlocked with the air intake volume.

[0026] In this invention: the microalgae aeration reactor periodically removes microalgae biomass, which can be added to the photoreactor.

[0027] A second aspect of this invention provides an optimized cultivation method for treating microalgae containing hydrogen sulfide tail gas:

[0028] S1: Select suitable microalgae species for pre-culture;

[0029] S2: Inoculate the pre-cultured microalgae into a culture medium containing appropriate nitrogen, phosphorus and carbon sources, and the culture time is generally about 5 to 20 days.

[0030] S3: Co-culturing with hydrogen sulfide optimizes the growth and reproduction of microalgae in a hydrogen sulfide environment, and increases the metabolic activity and resistance of microalgae to hydrogen sulfide.

[0031] S4: Under suitable light intensity and light cycle, maintain the pH of the culture medium between 6.5 and 8.0, the temperature between 15 and 40°C, and provide adequate oxygen to promote the growth and metabolism of microalgae.

[0032] S5: Collect microalgae.

[0033] In this invention: the microalgae include, but are not limited to, one or a mixture of green algae, blue algae, diatoms, and Chlamydomonas;

[0034] In this invention, the microalgae culture methods include static culture, suspension culture, flow culture, and continuous culture. Beneficial effects

[0035] This invention aims to provide a method for treating hydrogen sulfide-containing exhaust gas based on microalgae. This method employs a novel biological treatment technology, utilizing the adsorption, transformation, metabolism, and photolysis mechanisms of microalgae to achieve highly efficient removal of hydrogen sulfide. Compared with traditional hydrogen sulfide treatment methods:

[0036] (1) This method utilizes the photosynthesis and respiration of microalgae to absorb, transform, and fix hydrogen sulfide in waste gas. At the same time, the growth of microalgae releases a large amount of oxygen, which can further oxidize hydrogen sulfide and convert it into non-toxic substances such as sulfur, sulfate, and water, thereby achieving the purpose of efficiently removing hydrogen sulfide.

[0037] (2) Microalgae is a naturally growing biological resource, which has simple growth conditions, easy to cultivate, low cost, suitable for different environments and scenarios, has high applicability, no negative impact on the environment, and can be reused, with good sustainability. The method uses high-density culture and continuous gradient aeration, which effectively improves the utilization efficiency and desulfurization efficiency of microalgae.

[0038] (3) Using microalgae to treat hydrogen sulfide-containing waste gas will not produce secondary pollution, will not produce other waste and chemicals, and has little environmental pollution. Moreover, the useful substances produced by microalgae metabolism can be recycled and reused, reducing pollutant emissions. It can be widely used in industrial waste gas, sewage treatment and other fields, which can reduce air pollutant emissions, protect the environment, and at the same time, the biomass material produced can be recycled, realizing sustainable development.

[0039] (4) The microalgae desulfurization technology has the advantages of low cost, high treatment efficiency, energy saving and environmental protection. In addition, through reasonable microalgae cultivation and extraction methods, efficient recovery and reuse of microalgae can be achieved, further improving the economy and sustainability of the method, and having strong practicality and social value, with broad application prospect and popularization value. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The process flow diagram of the method for treating hydrogen sulfide-containing tail gas based on microalgae according to the embodiments of the present application is shown.

[0041] In the figure, 1 is a first reactor; 2 is a second reactor; 3 is a microalgae photoreactor; 4 is a microalgae aeration reactor; 5 and 6 are circulating pumps; and 7 is an electric heater. EMBODIMENT

[0042] In order to make the present application easier to understand, the present application will be described in detail below in combination with embodiments and examples, which are only illustrative and do not limit the scope of application of the present application.

[0043] All reagents used in the examples are commercially available analytical reagents.

[0044] The method for treating hydrogen sulfide-containing tail gas based on microalgae comprises the following steps:

[0045] S1: Selecting green algae, blue-green algae and chlorella and inoculating them in 9 culture devices, respectively, and marking them as A1, A2, A3, B1, B2, B3, C1, C2 and C3;

[0046] S2: Adding A1, B1 and C1 into the nutrient solution in batches, and irradiating under white light for 12 hours, keeping the temperature at 25℃, the pH value of the culture solution at 7.0-7.5, and the culture period at 15 days;

[0047] S3: A2, B2, C2 are added to the nutrient solution in batches, the light time is 12h under white light environment, the temperature is maintained at 25℃, 50ppm of hydrogen sulfide gas is introduced for optimization culture, and air is introduced, the pH value of the culture solution is 7.0-7.5, and the culture period is 15 days;

[0048] S4: A3, B3, C3 are added to the nutrient solution in batches, the light time is 12h under white light environment, the temperature is maintained at 25℃, 50ppm of hydrogen sulfide gas is introduced twice for optimization culture, and air is introduced, the pH value of the culture solution is 7.0-7.5, and the culture period is 15 days;

[0049] S5: Collecting microalgae: microalgae can be collected by precipitation, filtration, centrifugation and the like.

[0050] The cultured microalgae are subjected to hydrogen sulfide removal experiment, and the process flow is shown in FIG. 2. Figure 1 . Embodiment

[0051] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae, and the cultured microalgae desulfurization solution (green algae A1) is added to a desulfurization experimental device to prepare a microalgae desulfurization solution A1-1 containing 7 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0052] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the first reactor, is subjected to rough desulfurization by the microalgae solution sprayed downward, and is discharged from the top end to continue to enter the gas distributor of the second reactor, and is discharged from the top end to be vented after being fully contacted with the microalgae solution from top to bottom to absorb hydrogen sulfide;

[0053] S2: The microalgae solution containing hydrogen sulfide at the bottom of the first reactor and the second reactor is pumped into the microalgae photoreactor;

[0054] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 12L-12D, and the temperature is maintained at 25℃;

[0055] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 25℃, the pH value is 8.0, the ORP is-400ev, and the DO is 4 mg / L;

[0056] S5: The solution from the microalgae aeration system is pumped into the liquid distributor of the first reactor and the second reactor by the circulating pump to cyclically absorb hydrogen sulfide waste gas. Embodiment

[0057] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultivated microalgae desulfurization solution (green algae A2) is added into a desulfurization experimental device to prepare a microalgae desulfurization solution A2-1 containing 6.5 g / L of sodium carbonate. The specific desulfurization steps are as follows:

[0058] S1: the raw gas containing hydrogen sulfide enters the gas distributor of the primary reactor, is coarsely desulfurized by the microalgae solution sprayed downward, and is discharged from the top end to continue to enter the gas distributor of the secondary reactor, fully contacts the microalgae solution from top to bottom to absorb hydrogen sulfide, and is discharged from the top end to be vented;

[0059] S2: the microalgae solution containing absorbed hydrogen sulfide at the bottom of the primary reactor and the secondary reactor is pumped into the microalgae photoreactor;

[0060] S3: in the microalgae photoreactor, white light is used for illumination, the illumination cycle is 10L-14D, and the temperature is maintained at 25°C;

[0061] S4: the microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 25°C, the pH value is 8.0, the ORP is -380ev, and the DO is 4 mg / L;

[0062] S5: the solution from the microalgae aeration system is punched into the liquid distributor of the primary reactor and the secondary reactor by a circulating pump to cyclically absorb hydrogen sulfide waste gas. Embodiment

[0063] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultivated microalgae desulfurization solution (green algae A3) is added into a desulfurization experimental device to prepare a microalgae desulfurization solution A3-1 containing 6.5 g / L of sodium carbonate. The specific desulfurization steps are as follows:

[0064] S1: the raw gas containing hydrogen sulfide enters the gas distributor of the primary reactor, is coarsely desulfurized by the microalgae solution sprayed downward, and is discharged from the top end to continue to enter the gas distributor of the secondary reactor, fully contacts the microalgae solution from top to bottom to absorb hydrogen sulfide, and is discharged from the top end to be vented;

[0065] S2: the microalgae solution containing absorbed hydrogen sulfide at the bottom of the primary reactor and the secondary reactor is pumped into the microalgae photoreactor;

[0066] S3: in the microalgae photoreactor, white light is used for illumination, the illumination cycle is 8L-16D, and the temperature is maintained at 25°C;

[0067] S4: the microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 25°C, the pH value is 7.8, the ORP is -380ev, and the DO is 3.5 mg / L;

[0068] S5: The solution from the microalgae aeration system is pumped into the liquid distributors of the first and second reactors by a circulating pump to absorb hydrogen sulfide waste gas. Embodiment

[0069] This embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultured microalgae desulfurization solution (green algae A3) is added to the desulfurization experimental device to prepare a microalgae desulfurization solution A3-2 containing 6.5 g / L of sodium carbonate. The specific desulfurization steps are as follows:

[0070] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the second reactor, fully contacts with the microalgae solution from top to bottom to absorb hydrogen sulfide, and is discharged from the top end;

[0071] S2: The microalgae solution containing hydrogen sulfide at the bottom of the first and second reactors is pumped into the microalgae photoreactor;

[0072] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 10L-14D, and the temperature is maintained at 25°C;

[0073] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 20°C, the pH value is 7.8, the ORP is -380ev, and the DO is 4.5 mg / L;

[0074] S5: The solution from the microalgae aeration system is pumped into the liquid distributors of the first and second reactors by a circulating pump to absorb hydrogen sulfide waste gas. Embodiment

[0075] This embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultured microalgae desulfurization solution (green algae B1) is added to the desulfurization experimental device to prepare a microalgae desulfurization solution B1-1 containing 7.5 g / L of sodium carbonate. The specific desulfurization steps are as follows:

[0076] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the first reactor, is coarsely desulfurized by the microalgae solution sprayed from below, is discharged from the top end, and then enters the gas distributor of the second reactor, fully contacts with the microalgae solution from top to bottom to absorb hydrogen sulfide, and is discharged from the top end;

[0077] S2: The microalgae solution containing hydrogen sulfide at the bottom of the first and second reactors is pumped into the microalgae photoreactor;

[0078] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 12L-12D, and the temperature is maintained at 25°C;

[0079] S4: The microalgae solution overflowed from the microalgae photoreactor into the microalgae aeration system, air was introduced, the temperature was maintained at 25°C, the pH value was 8.0, the ORP was -400 ev, and the DO was 4 mg / L;

[0080] S5: The solution from the microalgae aeration system was pumped into the liquid distributors of the primary reactor and the secondary reactor by a circulating pump to recycle and absorb hydrogen sulfide waste gas. Embodiment

[0081] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. Cultured microalgae desulfurization solution (green algae B2) is added to a desulfurization experimental device to prepare microalgae desulfurization solution B2-1 containing 7.5 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0082] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the primary reactor, is coarsely desulfurized by the microalgae solution sprayed downward, is discharged from the top end, continues to enter the gas distributor of the secondary reactor, fully contacts and absorbs hydrogen sulfide from the microalgae solution from top to bottom, and is discharged from the top end and vented;

[0083] S2: The microalgae solution containing absorbed hydrogen sulfide at the bottom of the primary reactor and the secondary reactor is pumped into the microalgae photoreactor.

[0084] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 10L-14D, and the temperature is maintained at 25°C.

[0085] S4: The microalgae solution overflowed from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 25°C, the pH value is 8.0, the ORP is -400 ev, and the DO is 4 mg / L.

[0086] S5: The solution from the microalgae aeration system is pumped into the liquid distributors of the primary reactor and the secondary reactor by a circulating pump to recycle and absorb hydrogen sulfide waste gas. Embodiment

[0087] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. Cultured microalgae desulfurization solution (green algae B2) is added to a desulfurization experimental device to prepare microalgae desulfurization solution B2-1 containing 7.5 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0088] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the primary reactor, is coarsely desulfurized by the microalgae solution sprayed downward, is discharged from the top end, continues to enter the gas distributor of the secondary reactor, fully contacts and absorbs hydrogen sulfide from the microalgae solution from top to bottom, and is discharged from the top end and vented;

[0089] S2: The microalgae solution containing absorbed hydrogen sulfide at the bottom of the primary reactor and the secondary reactor is pumped into the microalgae photoreactor.

[0090] S3: In the microalgae photoreactor, white light is used for illumination, and the illumination cycle is 8L-16D, and the temperature is maintained at 25°C;

[0091] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 25°C, the pH value is 7.8, the ORP is-380ev, and the DO is 3.5 mg / L;

[0092] S5: The solution from the microalgae aeration system is pumped into the liquid distributor of the primary reactor and the secondary reactor by the circulating pump, and the hydrogen sulfide waste gas is recycled and absorbed. Embodiment

[0093] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultured microalgae desulfurization solution (green algae B3) is added to a desulfurization experimental device to prepare a microalgae desulfurization solution B3-2 containing 7.5 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0094] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the secondary reactor, fully contacts with the microalgae solution from top to bottom to absorb hydrogen sulfide, and is discharged and vented from the top end;

[0095] S2: The microalgae solution containing hydrogen sulfide at the bottom of the primary reactor and the secondary reactor is pumped into the microalgae photoreactor;

[0096] S3: In the microalgae photoreactor, white light is used for illumination, and the illumination cycle is 10L-14D, and the temperature is maintained at 25°C;

[0097] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 20°C, the pH value is 7.8, the ORP is-380ev, and the DO is 4.5 mg / L;

[0098] S5: The solution from the microalgae aeration system is pumped into the liquid distributor of the primary reactor and the secondary reactor by the circulating pump, and the hydrogen sulfide waste gas is recycled and absorbed. Embodiment

[0099] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultured microalgae desulfurization solution (green algae C1) is added to a desulfurization experimental device to prepare a microalgae desulfurization solution C1-1 containing 8 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0100] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the primary reactor, is coarsely desulfurized by the microalgae solution sprayed downward, is discharged from the top end, and then enters the gas distributor of the secondary reactor, fully contacts with the microalgae solution from top to bottom to absorb hydrogen sulfide, and is discharged and vented from the top end;

[0101] S2: The microalgae solution containing absorbed hydrogen sulfide at the bottom of the first reactor and the second reactor is pumped into the microalgae photoreactor;

[0102] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 12L-12D, and the temperature is maintained at 25°C;

[0103] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 25°C, the pH value is 8.0, the ORP is -400ev, and the DO is 4 mg / L;

[0104] S5: The solution from the microalgae aeration system is pumped into the liquid distributor of the first reactor and the second reactor by a circulating pump to absorb hydrogen sulfide waste gas. Embodiment

[0105] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultured microalgae desulfurization solution (green algae C2) is added to a desulfurization experimental device to prepare a microalgae desulfurization solution C2-1 containing 8 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0106] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the first reactor, is coarsely desulfurized by the microalgae solution sprayed downward, is discharged from the top end, continues to enter the gas distributor of the second reactor, is fully contacted with the microalgae solution from top to bottom to absorb hydrogen sulfide, and is discharged and vented from the top end;

[0107] S2: The microalgae solution containing absorbed hydrogen sulfide at the bottom of the first reactor and the second reactor is pumped into the microalgae photoreactor;

[0108] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 10L-14D, and the temperature is maintained at 25°C;

[0109] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 20°C, the pH value is 7.8, the ORP is -360ev, and the DO is 3.5 mg / L;

[0110] S5: The solution from the microalgae aeration system is pumped into the liquid distributor of the first reactor and the second reactor by a circulating pump to absorb hydrogen sulfide waste gas. Embodiment

[0111] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultured microalgae desulfurization solution (green algae C3) is added to a desulfurization experimental device to prepare a microalgae desulfurization solution C3-1 containing 7.6 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0112] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the first reactor, and the microalgae solution sprayed from the top is desulfurized and discharged from the top to continue to enter the gas distributor of the second reactor, and the microalgae solution from top to bottom is fully contacted and absorbed with hydrogen sulfide, and then discharged from the top and vented;

[0113] S2: The microalgae solution containing hydrogen sulfide at the bottom of the first reactor and the second reactor is pumped into the microalgae photoreactor;

[0114] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 8L-16D, and the temperature is maintained at 25°C;

[0115] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 20°C, the pH value is 7.8, the ORP is-360ev, and the DO is 3.5 mg / L;

[0116] S5: The solution from the microalgae aeration system is pumped into the liquid distributor of the first reactor and the second reactor by the circulating pump to recycle and absorb hydrogen sulfide waste gas. Embodiment

[0117] The embodiment provides a method for treating hydrogen sulfide-containing tail gas based on microalgae. The cultured microalgae desulfurization solution (green algae C3) is added to a desulfurization experimental device to prepare a microalgae desulfurization solution C3-2 containing 7.6 g / L of sodium carbonate, and the specific desulfurization steps are as follows:

[0118] S1: The raw gas containing hydrogen sulfide enters the gas distributor of the second reactor, and the microalgae solution from top to bottom is fully contacted and absorbed with hydrogen sulfide, and then discharged from the top and vented;

[0119] S2: The microalgae solution containing hydrogen sulfide at the bottom of the first reactor and the second reactor is pumped into the microalgae photoreactor;

[0120] S3: In the microalgae photoreactor, white light is used for illumination, the illumination cycle is 10L-14D, and the temperature is maintained at 25°C;

[0121] S4: The microalgae solution overflowing from the microalgae photoreactor enters the microalgae aeration system, air is introduced, the temperature is maintained at 20°C, the pH value is 7.8, the ORP is-370ev, and the DO is 4.5 mg / L;

[0122] S5: The solution from the microalgae aeration system is pumped into the liquid distributor of the first reactor and the second reactor by the circulating pump to recycle and absorb hydrogen sulfide waste gas.

[0123] Application example

[0124] A certain concentration of H2S raw gas was configured, and the microalgae desulfurization solution of examples 1-12 was used to treat the H2S raw gas, and the results are shown in table 1.

[0125] Table 1. Microalgae solution desulfurization data table

[0126] As shown in table 1, the method provided by the present application has high removal capacity for H2S-containing waste gas, can efficiently remove H2S gas, and at the same time, maintains the metabolic growth of microalgae.

[0127] It should be noted that the above-described examples are only used to explain the present application and do not constitute any limitation on the present application. The present application is described by referring to typical examples, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. The present application can be modified within the scope of the claims of the present application, and the present application can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and examples, it does not mean that the present application is limited to the specific examples disclosed therein, on the contrary, the present application can be extended to all other methods and applications with the same function.

Claims

1. A method for treating a sour hydrogen sulfide-containing tail gas based on microalgae, characterized in that: The hydrogen sulfide-containing tail gas treatment mainly comprises the following steps: S1: the pretreated hydrogen sulfide-containing tail gas is sent to the input end of the first reactor, the input end of the second reactor is connected with the output end of the first reactor, and the output end of the second reactor is connected with the tail gas discharge; S2: the microalgae desulfurization liquid enters the liquid distributor from the upper part of the first reactor and the second reactor, is uniformly sprayed in the reactor, fully contacts with the hydrogen sulfide-containing tail gas to absorb hydrogen sulfide, and is discharged from the bottom; one of sodium carbonate or potassium carbonate is matched in the microalgae desulfurization liquid, and the concentration is 0.5-10 g / L; S3: the discharged microalgae desulfurization liquid is sent to the heater and then enters the microalgae photoreactor, the light source is adjusted, the photosynthesis of the microalgae is promoted to produce nutrients and energy, and part of the sulfide in the liquid is converted into solid microalgae biomass; the light source used is selected from white light or natural light between 400-700 nm, and the illumination time is 6-18 h; S4: the solution flowing out of the microalgae photoreactor enters the microalgae aeration reactor, air is introduced through the aeration system, the temperature in the microalgae photoreactor and the microalgae aeration reactor is adjusted to 15-35℃, the pH value is adjusted to 6.0-8.5, the ORP value is-500--200 ev, and the DO value is 2-10 mg / L, so that the sulfide is catalyzed by the enzymes of the microalgae cells, reacts and metabolizes to generate sulfur and sulfate, and the sulfur conversion is carried out; the ORP value of the microalgae aeration reactor is interlocked with the air inlet amount; S5: the solution of the microalgae aeration reactor is sent to the first reactor and the second reactor for recycling; The microalgae need to be optimized and cultured first, and the specific optimization and culture method is as follows: S1: selecting the type of microalgae and pre-culturing; the microalgae include one or more of green algae, blue-green algae, diatoms and chlorella; S2: inoculating the pre-cultured microalgae into a culture medium containing a nitrogen source, a phosphorus source and a carbon source, and culturing for 5-20 days; S3: introducing hydrogen sulfide for co-culturing, optimizing the growth and reproduction of the microalgae in the hydrogen sulfide environment, and increasing the metabolic activity and resistance of the microalgae to hydrogen sulfide; S4: under the light intensity and light cycle, the pH value of the culture solution is maintained at 6.5-8.0, the temperature is maintained at 15-40℃, and oxygen is supplied to promote the growth and metabolism of the microalgae; S5: collecting the microalgae.

2. The method of claim 1, wherein: The microalgae photoreactor is made of machine glass material or transparent plastic film, and has a flat plate type, a column type, a tube type or a tapered light bioreactor type.

3. The method of claim 1, wherein: The density of the microalgae in the microalgae desulfurization liquid is 0.1-2.0 g / L.

4. The method of claim 1, wherein: The microalgae culture method includes static culture, suspension culture, flow culture or continuous culture.

5. The method of claim 1, wherein: The microalgae aeration reactor regularly takes out the microalgae biomass, and the microalgae biomass is added into the microalgae photoreactor.

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