WO2013107247A1

WO2013107247A1 - Method for cultivating microalgae and co-producing alkenes

Info

Publication number: WO2013107247A1
Application number: PCT/CN2012/087304
Authority: WO
Inventors: 刘中民; 董兴隆; 徐云鹏; 薛松; 张今令; 黄为
Original assignee: 中国科学院大连化学物理研究所
Priority date: 2012-01-20
Filing date: 2012-12-24
Publication date: 2013-07-25
Also published as: CN103215189A

Abstract

Provided is a method for cultivating microalgae using recycling and co-producing alkenes without requiring additional nutrient substances to be added. The method can be used for the cultivation of a microalgal suspension and the co-production of alkenes. The method primarily comprises a way to cultivate microalgae using recycling and co-produce alkenes using the recycling cultivation process. The collected microalgae are treated by hydrolysis so as to obtain the aqueous phase and the oil phase. The aqueous phase, being the nutrient solution for the cultivation of the microalgae using recycling, is added into the microalgae cultivation system, providing a carbon source, a nitrogen source, a phosphorus source and inorganic salt, so as to achieve the goal of recycling cultivation. The oil phase, obtained by separation, is cracked to prepare alkenes. The method is efficient in cultivating microalgae, brings a fast growth rate without requiring an additional nitrogen source and a phosphorus source as well as inorganic salt, and alkenes can be co-produced by this method.

Description

Method for parallel production of olefin by microalgae cultivation

The invention belongs to the field of microalgae cultivation, and in particular relates to a method suitable for the parallel production of olefins by microalgae and other photosynthetic biological cells. Background technique

Nowadays, with the depletion of fossil resources, the search for alternative green energy has received extensive attention. Microalgae is a kind of biological resource with great application value.

At present, the microalgae nutrition methods mainly include light autotrophic, heterogeneous and mixed nutrition. The photoautotrophic mode uses sunlight as an energy source, absorbs carbon dioxide as an inorganic carbon source, and adds inorganic salts to the nutrient solution to culture. Organic matter such as glucose can also be used to grow microalgae heterotrophic. The mixed nutrients are added to the photobioreactor to culture the microalgae. The photoautotrophic culture of microalgae has low cost and good algal cell quality, but it needs to add inorganic salt and nitrogen source phosphorus source. In addition, it has the disadvantages of low cell density, low growth efficiency, vulnerability to pollution and weather. The heterotrophic culture of microalgae has high growth efficiency and high algal cell density. However, in addition to the addition of inorganic salts and nitrogen source phosphorus sources, organic carbon sources need to be added. The heterotrophic cultured algae cells have low quality and cannot absorb carbon dioxide. Hybrid nutrition can both absorb sunlight by sunlight and maintain high growth efficiency.

Chinese patent CN101838606A proposes a self-supporting-heterotrophic coupling photobioreactor for wastewater treatment of carbon-reduced and circulated microalgae, using a model of autotrophic and heterogeneous coupling. By adding a heterotrophic zone, the carbon fixation efficiency is high and micro The algae culture concentration is high, suitable for sewage treatment carbon emission reduction and high-efficiency cultivation of microalgae on a large scale and low cost. Chinese patent CN102154110A proposes a high-yield method for cultivating microalgae, which is subjected to heterotrophic cultivation, and then the algae cells obtained by heterotrophic culture are used as seeds for self-cultivation. It can solve the problem of low growth efficiency in large-scale photoautotrophic culture of microalgae. Chinese patent CN101285075A proposes a coupling method for biogas fermentation and autotrophic freshwater microalgae cultivation. The biogas slurry is used as a culture medium for microalgae culture, and C0 _{2 in} biogas is used as a carbon source for self-cultivation of freshwater microalgae. Chinese patent CN101921811A uses the acid solution after the end of biogas fermentation as a medium to heterotrophic culture of the microalgae, and the resulting mixed gas is circulated into the photobioreactor for aeration and autotrophic culture. Chinese patent CN101914572A proposes a carbon dioxide zero The method for energy-saving utilization of waste organic waste, the biogas slurry after biogas fermentation is directly used as a whole nutrient medium of microalgae, and the biogas slurry and the inoculated algae liquid are mixed and then enter the photobioreactor, and the co-derived carbon dioxide storage tank is used. ₂ as a carbon source, carried out in the photosynthetic microalgae culture grow autotrophically fixing CO.'s ₂ ways. Chinese patent CN101575567A proposes a method for cultivating microalgae by light and a reactor thereof, and the dry weight concentration of the microalgae cells is more than 3.5 g/L when cultured for 5 days under the condition of 1% to 40% carbon dioxide. Chinese patent CN101979498A proposes a method for high-yield heterotrophic culture of microalgae. Using a semi-continuous culture method, during the cultivation process, a part of the algae liquid is released, and the same volume of the same medium and sterile water are added to achieve high yield. Rate training. Chinese patent CN102021208A proposes a method for rapidly accumulating intracellular fats and oils of microalgae. The heterotrophic cultured microalgae algae solution is diluted and subjected to light-induced culture, so that the microalgae rapidly accumulates in the light-induced stage. Chinese patent CN102089434A proposes an integrated system for the production of biofuel raw materials, which uses organic carbon and nutrients for heterotrophic seed culture, and then the resulting microalgae species are subjected to large-scale autotrophic cultivation for cell biomass accumulation. Chinese patent CN102174409A proposes a method for rapid growth and large accumulation of bio-oil by cultivating chlorella in mixed nutrient culture. The first stage uses chlorella autotrophic culture to obtain higher biomass, and the second stage uses aerated heterotrophic culture with added organic matter. Mode, the rapid accumulation of oil on a large biomass basis. Chinese patent CN101280328A proposes a method for producing biodiesel from self-cultivation to heterotrophic cultivation of chlorella, and transferring the concentrated autotrophic algae into a fermenter for heterotrophic growth to synthesize neutral fat. The biomass can reach 108g/L, and the oil content can reach 52% of the dry weight of the cells. Chinese patent CN1446882A—a method for preparing biodiesel by rapid pyrolysis of heterotrophic algae by amylase hydrolysis, using low-quality grain starch as raw material, enzymatically decomposing starch to make glucose, and obtaining heterotrophic chlorella, algal cells by heterotrophic transformation technology The preparation cost is reduced by 3-4 times; the fat content is 3-4 times higher than the autotrophic algae. Chinese patent CN101549932A proposes a production method of organic sewage waste residue treatment coupled with algae refining, which utilizes anaerobic biochemical technology to separately treat organic sewage and organic waste residue, and then aerobic biochemical treatment of sewage and biogas slurry, and then formulated into a culture solution. The oil-containing microalgae are cultured by the carbon dioxide exhaust gas generated after the combustion of the biogas. Chinese patent CN102161550A proposes a method for producing feed additives and purifying into medium water for livestock and poultry breeding. The biogas slurry after sewage treatment of livestock and poultry is filtered by ultrafiltration membrane and then enters photobioreactor for microalgae cultivation and separation. The microalgal slurry is fed into the fermentation/enzymatic tank (pool) for fermentation and enzymatic hydrolysis as a feed additive. Chinese patent CN200610089354.3 proposes a method for preparing olefins from vegetable oils or/and animal fats, and preparing ethylene and propylene by catalytic cracking using vegetable oils or/and animal fats and oils as raw materials. Alkene and butene. Chinese patent CN200710099839.5 proposes a catalytic conversion method of vegetable oil or/and animal fat, which is subjected to catalytic cracking reaction by contacting vegetable oil or/and animal fat raw material in a composite reactor with a catalyst containing modified zeolite beta. The target product is low-carbon olefins and gasoline, diesel, and heavy oil.

At present, the main products of microalgae conversion are biodiesel, bio-oil, and fuel products such as gases. The conversion of bio-alcohol bio-oil into low-carbon olefins such as ethylene, propylene and butene is a new research direction.

None of the prior art has addressed the low efficiency of photoautotrophic growth and the dependence of external carbon on heterotrophic addition. Summary of the invention

To overcome the difficulties in the prior art, the present invention provides a method for the parallel production of olefins for the cultivation of microalgae and other photosynthetic organism cells. The method of the invention utilizes a photobioreactor to carry out circulating culture of microalgae, and hydrolyzes a certain amount of microalgae collected by each generation and culture under a certain temperature and pressure, and obtains an aqueous phase and an oil phase by separation, and the aqueous phase serves as a nutrient. The liquid is added to the next-generation culture system for the cultivation of the microalgae, and the oil phase is catalytically cracked with the solid acid as a catalyst to prepare the low-carbon olefin. An advantage of the present invention is that no additional nutrients need to be added during the cycle culture of the microalgae.

The microalgae circulating culture method of the present invention for parallel production of olefins (hereinafter referred to as "the method of the present invention":) includes the following steps:

1) using a photobioreactor to culture microalgae, and hydrolyzing the microalgae collected by each generation at a temperature of 50 ° C to 250 ° C and a pressure of 0.1 MPa to 4.0 MPa to obtain a hydrolyzate;

2) separating the hydrolyzate obtained in the step 1) to obtain an aqueous phase and an oil phase, the aqueous phase being added as a nutrient solution to the next generation microalgae culture system to provide nutrition for the propagation of the microalgae, the oil phase being solid The acid is used as a catalyst for catalytic cracking reaction to prepare a low-carbon olefin;

In the process of circulating microalgae cultivation, no additional nutrients need to be added, especially the inorganic salt and nitrogen source phosphorus source that need to be added in the microalgae autotrophic mode.

In a preferred embodiment of the method of the invention, the microalgae are marine microalgae or freshwater microalgae.

In a preferred embodiment of the method of the present invention, the photobioreactor is a pipeline or a box reactor, and the circulation of the microalgae nutrient solution is a pump cycle or an airlift cycle. In a preferred embodiment of the method of the invention, the light source used in the photobioreactor can be a fluorescent lamp, a fluorescent lamp, sunlight or a mixture thereof, which can be used interchangeably.

In a preferred embodiment of the method of the invention, the collected microalgae can be processed into the form of dry microalgal flour or wet microalgae prior to hydrolysis.

In a preferred embodiment of the method of the present invention, the hydrolysis method of the microalgae may be acid hydrolysis under normal pressure, neutral condition hydrolysis under high temperature and high pressure or acid hydrolysis under high temperature and high pressure.

In a preferred embodiment of the process of the invention, the separation of the aqueous phase and the oil phase may be by liquid separation, filtration or extraction.

In a preferred embodiment of the process of the invention, the solid acid catalyst used in the catalytic cracking reaction may be a zeolite molecular sieve, preferably a natural or synthetic silicalite molecular sieve, a phosphoaluminum molecular sieve and a silicalite molecular sieve, more preferably HZSM-5 Molecular sieves. The catalytic cracking conditions are preferably set to: a temperature of 500 to 700 ° C, and a weight ratio of the solid acid catalyst to the oil phase of 1 to 50. The catalytic cracking reaction can be carried out in any of a solid fluidized bed, a circulating fluidized bed and a riser, and a solid bed reactor, a moving bed reactor.

In a preferred embodiment of the process of the present invention, the acid used in the acid hydrolysis may be selected from one or more of hydrochloric acid, sulfuric acid, and phosphoric acid, and may have a concentration of from 0.1 mol/L to 2 mol/L.

In another preferred embodiment of the method of the present invention, the high temperature and high pressure conditions may be a temperature of from 100 ° C to 250 ° C and a pressure of from 0.1 MPa to 4.0 MPa. The acid hydrolysis temperature under normal pressure may be 50 or more and 100 ° C or less, preferably 50 to 95 °C. Neutral conditional hydrolysis refers to hydrolysis in water or a dilute alkali solution (e.g., 5 to 10 wt% sodium hydroxide solution).

In the microalgae culture of conventional photoautotrophic mode, it is usually necessary to add sodium nitrate as a nitrogen source; sodium dihydrogen phosphate is added as a phosphorus source; potassium salt, sodium salt, calcium salt, iron salt, zinc salt, manganese salt, Inorganic salts such as magnesium salts, molybdenum salts, copper salts, and cobalt salts. In the cultivation of heterotrophic methods, it is usually necessary to continuously add an additional organic carbon source from the outside to maintain the growth of the microalgae.

According to the method of the present invention, the amino acid, glucose and glycerol contained in the aqueous phase obtained by separating the hydrolyzate can be used as a carbon source for the growth of the next generation microalgae; the amino acid can be used as a nitrogen source; the water-soluble phosphate can be used as a phosphorus source; The potassium salt, sodium salt, calcium salt, iron salt, zinc salt, manganese salt, magnesium salt, molybdenum salt, copper salt, cobalt salt or the like can be used as the inorganic salt component.

Further, in the method of the present invention, the oil phase obtained by separating the hydrolyzate mainly contains a fatty acid which is subjected to catalytic cracking to obtain a low-carbon olefin. In the present invention, a light olefin refers to 4 carbon atoms. Lower olefins, for example, ethylene, propylene and butene. The beneficial effects of the invention:

1. The method of the present invention solves the problem of low photoautotrophic growth efficiency and external carbon-dependent addition in heterotrophy, and is capable of co-production of olefins.

2. The method of the invention does not need to additionally add inorganic nutrient salts and organic carbon in the microalgae culture, has high growth efficiency and fast growth speed, and realizes the method of circulating culture. detailed description

The invention will be further illustrated by the following examples. However, it should be understood that the examples are for illustrative purposes only and are not intended to limit the scope and spirit of the invention. Comparative example

The initial concentration was 5 χ 10 ⁶ cells per ml of 10 L microalgae broth, and standard f/2 broth was added. Each liter contains 75 mg NaN0 ₃ , 5 mg NaH ₂ P0 ₄ -H ₂ 0. 3.15 mg FeCl ₃ -6H ₂ 0, 4.36 mg Na ₂ EDTA, 0.0098 mg CuSO ₄ -5H ₂ O, 0.0063 mg Na ₂ Mo0 ₄ -2H ₂ 0, 0.022 mg ZnS0 ₄ -7H ₂ 0, 0.01 mg CoCl ₂ -6H ₂ 0, 0.18 mg MnCl ₂ -4H ₂ 0. 0.001 mg Vitamin B ₁₂ , 0.2 mg Vitamin Bl, 0.001 mg biotin. Light The bioreactor is made of hard silicon borosilicate glass. 2-4 30W fluorescent tubes are evenly distributed around the reactor. The constant temperature water bath is controlled at 25-30 °C, and a 3wt% C0 ₂ air mixture is introduced. The gas flow rate is 200ml/ Mm. After 7 days of culture, the density was lg/L, and after collecting and drying, 10 g of algal flour was obtained. Example 1

18 g of the collected algae powder was added to 90 ml of a 5% by weight hydrochloric acid solution, and heated at 50 ° C for 2 hr under normal pressure, and filtered to obtain 6.3 g of a filter cake, and the hydrolysis rate was 65%. The filter cake was extracted with n-hexane to obtain 3.3 g of an extract, which was added to a fixed bed reactor, and the treatment temperature was programmed from room temperature to 700 ° C, and the temperature was raised at 10 ° C / min. The catalytic cracking reaction temperature is 600 °C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the ratio of the agent to the mixture is 10, the reaction pressure is 0.1 MPa, and the low carbon olefin (ethylene, propylene, butene) mass yield is 43.0%, liquid The product quality yield was 25.7%, mainly toluene and xylene. The filtrate was neutralized with 10% by weight aqueous NaOH solution and added to the beginning. The initial concentration is 5χ 10 ⁶ cells per ml of 10L microalgae culture solution. The photobioreactor is a plate-box reactor made of hard silicon borosilicate glass. The reactor is evenly distributed around 2-4 30W fluorescent tubes. The water bath was controlled at 25-30 ° C, and a 3 wt% CO ₂ air mixture was introduced, and the gas flow rate was 200 ml/min. The microalgae grew rapidly. After 3 days of culture, the density was 4><10 ⁷ cells per ml, and after 7 days, the density was 1.77 g/L. After collecting and drying, 17.7 g of algal flour was obtained. Example 2

18 g of the collected algae algae powder was added to 90 ml of a 5% by weight hydrochloric acid solution, and the mixture was heated under reflux at normal pressure and 100 ° C for 2 hr, and filtered to obtain a filter cake of 6.3 g, and a hydrolysis rate of 65%. The filter cake was extracted with n-hexane to obtain 3.3 g of an extract, which was added to a fixed bed reactor, and the treatment temperature was programmed from room temperature to 700 ° C, and the temperature was raised at 10 ° C / min. The catalytic cracking reaction temperature is 600 °C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the ratio of the agent to the material is 10, the reaction pressure is 0.1 MPa, and the mass yield of the low-carbon olefin (ethylene, propylene, butylene) is 44.28%. The product quality yield was 20%, mainly toluene and xylene. The filtrate was neutralized with 10% by weight aqueous NaOH solution and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass. 2-4 30W fluorescent tubes were evenly distributed around the reactor. The constant temperature water bath was controlled at 25-30 °C, and a 3 wt% CO ₂ air mixture was introduced. The gas flow rate was 200 ml/min. The microalgae grew rapidly. After 3 days of culture, the density was 4><10 ⁷ cells per ml, and after 7 days, the density was 1.78 g/L. After collecting and drying, 17.8 g of algal flour was obtained. Example 3

18 g of the collected chlorella algae powder was added to 90 ml of a 5% by weight hydrochloric acid solution, and heated at 80 ° C for 2 hr under normal pressure to obtain a filter cake of 7.3 g, and a hydrolysis rate of 59.4%. The filter cake was extracted with n-hexane, and the hexane was rotary evaporated to give 1.82 g of product, which was then charged to a fixed-bed reactor, and the temperature of the treatment was from room temperature to 700 ° C, and the temperature was raised at 10 ° C / min. The catalytic cracking reaction temperature is 600 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the ratio of the agent to the mixture is 10, the reaction pressure is 0.1 MPa, and the low carbon olefin (ethylene, propylene, butene) mass yield is 33.0%, liquid The product mass yield was 36.2%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a plate-box reactor made of hard borosilicate glass, and the reactor was evenly distributed around 2-4. 30W fluorescent tube, constant temperature water bath control At 25-30 ° C, a 3 wt% CO ₂ air mixture was introduced, and the gas flow rate was 200 ml/min. The microalgae grew rapidly, and the density was 1.69 g/L after 7 days of culture. After collecting and drying, 16.9 g of algal flour was obtained. Example 4

18 g of the collected algae powder was added to 90 ml of a 5% sulfuric acid solution, and heated at 95 ° C for 2 hr under normal pressure, and filtered to obtain 7.7 g of a filter cake, and the hydrolysis rate was 57%. The filter cake was extracted with n-hexane, and the hexane was rotary evaporated. The obtained product was added to a fixed-bed reactor, and the temperature was elevated from room temperature to 700 ° C, and the heating rate was 10 ° C / min. The catalytic cracking reaction temperature is 600 °C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the ratio of the agent to the mixture is 50, the reaction pressure is 0.1 MPa, and the low carbon olefin (ethylene, propylene, butene) mass yield is 48.50%, liquid The product quality yield was 18.9%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution with an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was made of hard borosilicate glass, and 2-4 30W fluorescent tubes were evenly distributed around the reactor. Controlled at 25-30 ° C, a 3 wt% CO ₂ air mixture was introduced, and the gas flow rate was 200 ml/min. The microalgae grew rapidly. After 3 days of culture, the density was 3.3 χ 10 ⁷ cells per ml, and after 7 days, the density was 1.46 g/L. After collecting and drying, 14.6 g of algal flour was obtained. Example 5

18 g of the collected algae algae powder was added to 90 ml of a 5% phosphoric acid solution, and the mixture was heated under reflux at normal pressure and 100 ° C for 2 hr, and filtered to obtain 10.9 g of a cake. The hydrolysis rate was 39%. The filter cake was extracted with n-hexane, and the hexane was rotary evaporated. The obtained product (2.1 g) was charged to a fixed-bed reactor, and the treatment temperature was programmed from room temperature to 700 ° C, and the heating rate was 10 ° C / min. The catalytic cracking reaction temperature is 600 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the ratio of the agent to the material is 1, the reaction pressure is 0.1 MPa, and the low carbon olefin (ethylene, propylene, butene) mass yield is 41.72%, liquid The product quality yield was 23%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution with an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was made of hard borosilicate glass, and 2-4 30W fluorescent tubes were evenly distributed around the reactor. The water bath was controlled at 25-30 ° C, and a 3 wt% CO ₂ air mixture was introduced, and the gas flow rate was 200 ml/min. The microalgae grew rapidly. After 3 days of culture, the density was 2χ10 ⁷ cells per ml, and after 7 days, the density was 0.88 g/L. After collecting and drying, 8.8 g of algal flour was obtained. Example 7

18 g of the collected algae algae powder was added to 90 ml of water, placed in a 200 ml autoclave, and reacted at 150 ° C for 10 hr at 0.2 MPa, cooled, and filtered to obtain 6.2 g of a filter cake, and the hydrolysis rate was 65.6%. The filter cake was extracted with n-hexane, and hexanyl was rotary evaporated to obtain 3.3 g of product, which was added to a fixed-bed reactor, and the temperature was elevated from room temperature to 700 ° C, and the heating rate was 10 ° C / min. The catalytic cracking reaction temperature is 600 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the dosage ratio is 20, the reaction pressure is 0.1 MPa, and the low carbon olefin (ethylene, propylene, butylene) mass yield is 43.0%, liquid The product quality yield was 25.7%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5 χ ^{10 6} cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass. 2-4 30W fluorescent tubes were evenly distributed around the reactor. The constant temperature water bath was controlled at 25-30 ° C, and a 3 wt% CO ₂ air mixture was introduced, and the gas flow rate was 200 ml/min. The microalgae grew rapidly, and after 7 days of culture, the density was 1.77 g/L, and after collecting and drying, 17.7 g of algal flour was obtained. Example 8

The collected chlorella algae powder was 18 g, added with 90 ml of water, placed in a 200 ml autoclave, and reacted at 100 ° C for 10 hr at 0.5 MPa, cooled and filtered to obtain a filter cake of 7.2 g, and a hydrolysis rate of 60.0%. The filter cake was extracted with n-hexane and rotary-evaporated to obtain 1.80 g of the product, which was charged to a fixed-bed reactor, and the temperature of the treatment was programmed from room temperature to 700 ° C, and the temperature was raised at 10 ° C / min. The catalytic cracking reaction temperature is 600 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the dosage ratio is 20, the reaction pressure is 0.1 MPa, the low carbon olefin (ethylene, propylene, butene) mass yield is 34.9%, liquid The product quality yield was 35.9%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5χ10 ⁶ cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass, and the reactor was evenly distributed around 2-4 30W. fluorescent tubes, thermostat water bath controlled at 25-30 ° C, into 3wt% C0 ₂ containing air mixture, a gas flow rate of 200ml / min. The microalgae grew rapidly, and the density was 1.67 g/L after 7 days of culture. After collecting and drying, 16.7 g of algal flour was obtained. Example 9 18 g of the collected algae algae powder was added to 90 ml of a 5% (by weight) hydrochloric acid solution, placed in a 200 ml autoclave, and reacted at 150 ° C for 10 hr under a pressure of 1 MPa, cooled and filtered to obtain a filter cake of 5.5 g, a hydrolysis rate of 69.4. %. The filter cake was extracted with n-hexane and the hexane was rotary evaporated to give 3.4 g of product which was taken to a fixed-bed reactor. The temperature of the treatment was from room temperature to 700 ° C, and the temperature was raised at 10 ° C / min. The catalytic cracking reaction temperature is 700 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the reaction pressure is 0.1 MPa, the dosage ratio is 10, and the low carbon olefin (ethylene, propylene, butylene) mass yield is 42.3%, liquid The product quality yield was 22.4%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass, and 2-4 branches were uniformly distributed around the reactor. 30W fluorescent tube, constant temperature water bath control at 25-30 °C, with a 3wt% C0 ₂ air mixture, gas flow rate of 200ml / min. The microalgae grew rapidly, and the density was 1.81 g/L after 7 days of culture. After collecting and drying, 18.1 g of algal flour was obtained. Example 10

18 g of the collected algae algae powder, 90 ml of a 10% by weight sulfuric acid solution, and placed in a 200 ml autoclave, reacted at 150 ° C for 10 hr at 3 MPa, cooled and filtered to obtain a filter cake of 6.5 g, a hydrolysis rate of 63.9%. . The filter cake was extracted with n-hexane and rotary-evaporated to obtain 3.4 g of the product, which was added to a fixed bed reactor, and the treatment temperature was programmed from room temperature to 700 ° C, and the heating rate was 10 ° C / mm. The catalytic cracking reaction temperature is 500 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the ratio of the agent to the mixture is 30, the reaction pressure is 0.1 MPa, and the low carbon olefin (ethylene, propylene, butene) mass yield is 43.5%, liquid The product quality yield was 20.7%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass, and 2-4 branches were uniformly distributed around the reactor. 30W fluorescent tube, the constant temperature water bath is controlled at 25-30 °C, and a 3 wt% CO ₂ air mixture is introduced, and the gas flow rate is 200 ml/min. The microalgae grew rapidly, and the density was 1.64 g/L after 7 days of culture. After collecting and drying, 16.4 g of algal flour was obtained. Example 11

18 g of the collected algae powder, added 90 ml of a 10% by weight sodium hydroxide solution, placed in a 200 ml autoclave, reacted at 150 ° C for 10 hr at 0.1 MPa, cooled and filtered. A filter cake was obtained in an amount of 10.5 g, and the hydrolysis rate was 41.6%. The filter cake was extracted with n-hexane and the hexane was rotary evaporated to obtain 2.4 g of the product, which was added to a fixed-bed reactor, and the temperature was elevated from room temperature to 700 ° C, and the heating rate was 10 ° C / min. The catalytic cracking reaction temperature is 600 °C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the reaction pressure is 0.1 MPa, the dosage ratio is 1, and the low carbon olefin (ethylene, propylene, butylene) mass yield is 36.5%, liquid The product quality yield was 17.9%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass, and 2-4 branches were uniformly distributed around the reactor. 30W fluorescent tube, the constant temperature water bath is controlled at 25-30 °C, and a 3 wt% CO ₂ air mixture is introduced, and the gas flow rate is 200 ml/min. The microalgae grew rapidly, and the density was 1.02 g/L after 7 days of culture. After collecting and drying, 10.2 g of algal flour was obtained. Example 12

18 g of the collected algae algae powder was added to 90 ml of water, placed in a 200 ml autoclave, and reacted at 100 ° C for 10 hr at 4 MPa, cooled, and filtered to obtain 16.7 g of a filter cake, and the hydrolysis rate was 7.2%. The filter cake was extracted with n-hexane, and hexanyl oxime was rotary evaporated to obtain 0.9 g of product, which was added to a fixed-bed reactor, and the treatment temperature was programmed from room temperature to 700 ° C, and the heating rate was 10 ° C / min. The catalytic cracking reaction temperature is 600 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the reaction pressure is 0.1 MPa, the dosage ratio is 10, and the low carbon olefin (ethylene, propylene, butylene) mass yield is 32.9%, liquid The product mass yield was 14.4%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass, and 2-4 branches were uniformly distributed around the reactor. 30W fluorescent tube, the constant temperature water bath is controlled at 25-30 °C, and a 3 wt% CO ₂ air mixture is introduced, and the gas flow rate is 200 ml/min. After 7 days of culture, the density was 0.12 g/L, and after collecting and drying, 1.2 g of algal flour was obtained. Example 13

18 g of the collected algae algae powder was added to 90 ml of water, placed in a 200 ml autoclave, and reacted at 250 ° C for 10 hr under IMPa, cooled and filtered to obtain 4.2 g of a filter cake, and the hydrolysis rate was 76.7%. The filter cake was extracted with n-hexane, and hexanyl was rotary evaporated to obtain 3.6 g of a product which was charged to a fixed-bed reactor, and the temperature of the treatment was from room temperature to 700 ° C, and the heating rate was 10 ° C / min. The catalytic cracking reaction temperature is 600 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, and the reaction pressure is O.lMPa, the ratio of the agent to the material is 10, the mass yield of the light olefin (ethylene, propylene, butylene) is 43.8%, and the mass yield of the liquid product is 33.7%, mainly toluene and xylene. The filtrate was neutralized and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a tubular reactor made of hard borosilicate glass, and 2-4 branches were uniformly distributed around the reactor. 30W fluorescent tube, the constant temperature water bath is controlled at 25-30 °C, and a 3 wt% CO ₂ air mixture is introduced, and the gas flow rate is 200 ml/min. The microalgae grew rapidly, and after 7 days of culture, the density was 1.77 g/L, and after collecting and drying, 17.7 g of algal flour was obtained. Example 14

The collected wet algae mud 54g, water content 67%, of which dry algae powder amount is 18g, added 7% (by weight) hydrochloric acid solution 64ml, heated at normal pressure and 50 ° C for 2hr, filtered to obtain filter cake 6.3g , hydrolysis rate of 65%. The filter cake was extracted with n-hexane to obtain 3.3 g of an extract, which was added to a fixed bed reactor, and the treatment temperature was programmed from room temperature to 700 ° C, and the temperature was raised at 10 ° C / min. The catalytic cracking reaction temperature is 600 ° C, the catalytic cracking catalyst is HZSM-5 molecular sieve, the reaction pressure is 0.1 MPa, the dosage ratio is 10, and the low carbon olefin (ethylene, propylene, butylene) mass yield is 43.0%, liquid The product quality yield was 25.7%, mainly toluene and xylene. The filtrate was neutralized with 10% by weight aqueous NaOH solution and added to a 10 L microalgae culture solution having an initial concentration of 5 χ 10 ⁶ cells per ml. The photobioreactor was a plate-box reactor made of hard borosilicate glass. 2-4 30W fluorescent tubes are evenly distributed around the reactor. The constant temperature water bath is controlled at 25-30 °C, and a 3 wt% CO ₂ air mixture is introduced. The gas flow rate is 200 ml/min. The microalgae grew rapidly. After 3 days of culture, the density was 4χ10 ⁷ cells per ml, and after 7 days, the density was 1.77 g/L. After collecting and drying, 17.7 g of algal flour was obtained.

Claims

A method for circulating microalgae to produce olefins in parallel, the method comprising the following steps:

In the process of circulating culture of microalgae, no additional nutrients need to be added.

2. A method according to claim 1, characterized in that the microalgae are marine microalgae or freshwater microalgae.

3. A method according to claim 1, characterized in that the photobioreactor is a pipeline or a box reactor, and the circulation of the microalgae nutrient solution is a pump cycle or an airlift cycle.

4. A method according to claim 1, characterized in that the photobioreactor uses a light source of a fluorescent lamp, a fluorescent lamp, sunlight or mixing them and using them alternately.

5. A method according to claim 1 wherein the collected microalgae are processed into the form of dry microalgal flour or wet microalgae prior to hydrolysis.

The method according to claim 1, characterized in that the hydrolysis method of the microalgae is acid hydrolysis under normal pressure, neutral condition hydrolysis under high temperature and high pressure or acid hydrolysis under high temperature and high pressure.

7. A method according to claim 1 wherein the separation of the aqueous phase and the oil phase is by liquid separation, filtration or extraction.

8. Process according to claim 1, characterized in that the solid acid catalyst is a zeolite molecular sieve, preferably a natural or synthetic silicoalumino zeolite molecular sieve, a phosphorus aluminum molecular sieve and a silicoaluminophosphate molecular sieve, more preferably a HZSM-5 molecular sieve.

The method according to claim 6, wherein the acid used in the acid hydrolysis is one or more of hydrochloric acid, sulfuric acid, and phosphoric acid, and has a concentration of 0.1 mol/L to 2 mol/L.

10. The method according to claim 6, wherein the high temperature and high pressure conditions are a temperature of from 100 ° C to 250 ° C and a pressure of from 0.1 MPa to 4.0 MPa.