CN106994300A - Method by the use of sanitary sewage as the microalgae flue gas carbon sequestration denitrification apparatus of water source and nutrient source and its for flue gas carbon sequestration denitration - Google Patents

Abstract

A microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and nutrient source and its method for flue gas carbon fixation and denitrification, relating to a flue gas carbon fixation and denitrification device and its use for flue gas carbon fixation and denitrification method. The method solves the problem that the existing pure flue gas cultivation of microalgae lacks nutrient sources such as nitrogen and phosphorus. The device consists of an air extraction pump, a flue gas treatment system, a photobioreactor, a gas direction pipe, an algae liquid direction pipe, a gas flow controller and a liquid suction pump. Methods: 1. obtaining microalgae; 2. flue gas treatment steps; 3. circulating algae and flue gas treatment. The invention is used for a microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and a nutrient source and a method for flue gas carbon fixation and denitrification.

Description

Microalgae flue gas carbon fixation and denitrification device using domestic sewage as water source and nutrient source Its method for carbon fixation and denitrification of flue gas

technical field

The invention relates to a flue gas carbon fixation and denitrification device and a method for flue gas carbon fixation and denitrification.

Background technique

In recent years, due to the global warming effect and energy crisis, microalgae have received extensive attention. Microalgae are a class of organisms that can use carbon dioxide for photosynthesis and fix it into their own biomass such as oil. They have the advantages of fast growth rate and high energy conversion efficiency. In the 1990s, Japanese researchers reported that many microalgae strains could not only use carbon dioxide in flue gas as a carbon source, but also use nitric oxide as a nitrogen source to synthesize their own proteins. This discovery has promoted the research and development of microalgae for flue gas denitrification technology. However, flue gas has the characteristics of high carbon dioxide concentration, high acidity, and complex composition. Most algae species cannot tolerate it. Even the algae species that can tolerate it need to reach a certain cell concentration. The cultivation process of microalgae requires a large amount of water, nitrogen and phosphorus nutrients. The consumption of water and nutrients in the microalgae cultivation process increases the production cost of the entire microalgae flue gas treatment technology and limits the industrial application of microalgae for flue gas denitrification.

Today, the scarcity of water resources is the main bottleneck restricting the development of human beings in the 21st century, and the use of drinking water for microalgae cultivation will inevitably lead to more water resource problems. At this stage, studies on the use of domestic sewage or industrial flue gas to cultivate microalgae are common, but there are no reports on the coupling of the two to use domestic sewage to cultivate microalgae and use carbon dioxide in the flue gas as a carbon source for flue gas denitrification.

Contents of the invention

The present invention aims to solve the problem that the existing pure flue gas cultivation of microalgae lacks nutrients such as nitrogen and phosphorus, thereby providing a microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and a nutrient source and its use in flue gas Gas-fixed carbon denitrification method.

The microalgae flue gas carbon fixation denitrification device using domestic sewage as a water source and nutrient source consists of an air extraction pump, a flue gas treatment system, a photobioreactor, a gas direction pipe, an algae liquid direction pipe, a gas flow controller and a liquid suction pump. ;

The flue gas treatment system is composed of a flue gas treatment reactor;

Or the flue gas treatment system is composed of two or more flue gas treatment reactors connected in series;

The flue gas treatment reactor is an air-lift cylindrical photobioreactor, the aspect ratio of the flue gas treatment reactor is (10-20):1; and the lower part of the flue gas treatment reactor is provided with a flue gas inlet, The upper part is equipped with flue gas outlet and algae liquid inlet;

The photobioreactor is an air-lift cylindrical photobioreactor, and the height-to-diameter ratio of the photobioreactor is (10-20):1; Exit, the upper part is equipped with a flue gas outlet;

The outlet of the air extraction pump is connected with the flue gas inlet of the flue gas treatment system through the gas direction pipe, and the flue gas outlet of the flue gas treatment system is connected with the flue gas inlet of the photobioreactor through the gas direction pipe; and the air extraction pump is connected with the flue gas There is a gas flow controller between the processing systems;

The algae liquid outlet of the photobioreactor is connected to the algae liquid inlet of each flue gas treatment reactor through the algae liquid direction pipe; and a liquid pump is arranged between the photobioreactor and the flue gas treatment system;

Each flue gas treatment reactor and photobioreactor are inoculated with an algae solution with an OD687 greater than 1.5; the algae solution is obtained by growing microalgae inoculated in a medium, and the medium is a BG11 medium or passed through a Domestic sewage after grade treatment; the pH of the medium=6～9, COD=100mg/L～400mg/L, TN=15mg/L～50mg/L, TP=2mg/L～10mg/L;

The microalgae are Chlorella, Micromansella or Scenedesmus.

The method of using the microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and nutrient source for flue gas carbon fixation and denitrification is carried out according to the following steps:

1. Obtain microalgae:

First inoculate the microalgae into the culture medium, and then culture under the conditions of light, temperature 20°C-30°C and CO ₂ to obtain the algae liquid with OD687 greater than 1.5; the ventilation rate of CO ₂ during the culture process is 0.05vvm ～0.3vvm, the light intensity is 1000lux～3000lux, and the light time is 8h～12h per day;

The medium is BG11 medium or domestic sewage after primary treatment; the pH of the medium is 6-9, COD=100mg/L-400mg/L, TN=15mg/L-50mg/L, TP=2mg/L～10mg/L; The microalgae is Chlorella, Micromansella or Scenedesmus;

2. Flue gas treatment steps:

Inoculate the algae liquid with OD687 greater than 1.5 into each flue gas treatment reactor and photobioreactor, connect the flue gas outlet of the desulfurization tower with the inlet of the suction pump, turn on the suction pump, and feed into the flue gas treatment system Flue gas, control the ventilation rate of the flue gas to 0.05vvm ~ 0.3vvm, and then carry out the flue gas treatment of the flue gas treatment system and the algae cultivation of the photobioreactor under the conditions of light and temperature of 20 ° C ~ 30 ° C, The light intensity is 1000lux~3000lux, the light time is 8h~12h per day, and during the process of flue gas treatment and algae cultivation, culture medium is added to the flue gas treatment reactor and photobioreactor respectively to ensure that the flue gas treatment reactor and the The microalgae grow in the algae liquid in the photobioreactor, and when the OD687 of the algae liquid in the flue gas treatment reactor remains constant, the growth of the microalgae enters a stable period;

The medium is BG11 medium or domestic sewage after primary treatment; the pH of the medium is 6-9, COD=100mg/L-400mg/L, TN=15mg/L-50mg/L, TP=2mg/L～10mg/L; the algae liquid with OD687 greater than 1.5 accounts for 2/3 of the volume of the flue gas treatment reactor and the photobioreactor respectively;

3. Cyclic algae cultivation plus flue gas treatment:

①. Collect microalgae as raw materials for biodiesel or methane production by fermentation, turn on the liquid pump, and feed algae liquid into each flue gas treatment reactor to ensure that the OD687 of the algae liquid in the flue gas treatment reactor is greater than 1.5, then close Suction pump;

②. When the OD687 of the algae liquid in the flue gas treatment reactor remains constant, the growth of microalgae enters a stable period. Repeat step 3 ① to complete the microalgae flue gas carbon fixation denitrification device using domestic sewage as a water source and nutrient source. A method for carbon fixation and denitrification of flue gas.

Advantages of the present invention: the present invention relates to a microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and nutrient source, and a new method and system for realizing flue gas denitrification by using _CO2 in flue gas as a carbon source . It mainly includes the following steps: use the domestic sewage that has undergone primary treatment as a culture solution, add algae, and cultivate under the conditions of light and CO ₂ until the microalgae reaches a certain concentration; then inoculate it into the flue gas treatment reactor And in the photobioreactor, it is used as algae species for flue gas treatment, the flue gas from the desulfurization tower outlet is introduced from the bottom of the flue gas treatment reactor, and the microalgae can use the CO ₂ in the flue gas as a carbon source to grow and at the same time Use NO _X as a nitrogen source to achieve carbon fixation and denitrification of flue gas; the flue gas at the outlet of the flue gas treatment reactor is connected to the photobioreactor for microalgae cultivation. At this time, the culture solution in the photobioreactor is still processed Primary treatment of domestic sewage; after the growth of microalgae in the flue gas treatment reactor reaches a stable period, the biomass is collected for biodiesel extraction, and then the photobioreactor is used to provide sufficient algae species for the flue gas treatment reactor , and so on.

Using several strains of chlorella, micromansella or Scenedesmus obtained in the early stage that can tolerate actual sewage and actual smoke, apply the device of the present invention to actual sewage and simulated smoke, and use natural and artificial light sources to cultivate for seven days , the cell concentration can reach 2.0g/L-3.0g/L, the _CO2 fixation efficiency can reach 5%-20%, the _NOX removal rate can reach 20%-40%, and the oil content of harvested microalgae biomass is 15% to 25%, the nitrogen and phosphorus in the sewage are basically used up, and the removal rate is above 90%.

The device of the present invention is used in field experiments of actual sewage and actual flue gas. After seven days of experimentation, the concentration of microalgae cells can reach 1.5g/L to 2.5g/L, and the fixation rate of a single flue gas treatment reactor to _CO is between 5% to 15%, the NO _X removal rate is 20% to 40%, the CO ₂ fixation rate of two flue gas treatment reactors connected in series can reach 10% to 30%, and the NO _X removal rate can reach 30% to 30%. 80%, and the oil content of the finally collected algae cells is about 20%.

Thus, the removal efficiency of the whole system for _NOx in flue gas can reach 25%-80%, the fixation efficiency of _CO2 can reach 5%-30%, and the removal of nitrogen and phosphorus in sewage can also reach more than 90%. When the NO _X concentration in the flue gas at the inlet of the system is lower than 100 mg/m ³ , the outlet concentration is lower than 50 mg/m ³ , which can achieve ultra-low emission of NO _X in the flue gas, and at the same time make the nitrogen and phosphorus concentration in the wastewater reach the standard discharge . This device not only overcomes the problem of water source for microalgae cultivation in the process of microalgae flue gas denitrification, but also reduces the investment cost of microalgae system for flue gas denitrification, and finally can harvest a large amount of microalgae biomass that can be used as microalgae biodiesel The provision of raw materials is beneficial to the industrial application of microalgae for carbon fixation and denitrification of flue gas.

Description of drawings

Fig. 1 is a schematic diagram of a microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and a nutrient source according to the present invention.

detailed description

Specific Embodiment 1: In combination with Fig. 1, this embodiment is a microalgae flue gas-fixed carbon denitrification device that uses domestic sewage as a water source and a nutrient source. Tube 4, algae liquid direction tube 5, gas flow controller 6 and liquid pump 7;

The flue gas treatment system 2 is composed of a flue gas treatment reactor 2-1;

Or the flue gas treatment system 2 is composed of two or more flue gas treatment reactors 2-1 connected in series;

The flue gas treatment reactor 2-1 is an air-lift cylindrical photobioreactor, and the aspect ratio of the flue gas treatment reactor 2-1 is (10-20):1; and the flue gas treatment reactor 2- The lower part of 1 is provided with a flue gas inlet, and the upper part is provided with a flue gas outlet and an algae liquid inlet;

The photobioreactor 3 is an air-lift cylindrical photobioreactor, and the height-to-diameter ratio of the photobioreactor 3 is (10-20):1; And algae liquid outlet, the upper part is equipped with flue gas outlet;

The outlet of the exhaust pump 1 is connected to the flue gas inlet of the flue gas treatment system 2 through the gas direction pipe 4, and the flue gas outlet of the flue gas treatment system 2 is connected to the flue gas inlet of the photobioreactor 3 through the gas direction pipe 4; And a gas flow controller 6 is provided between the air extraction pump 1 and the flue gas treatment system 2;

The outlet of the algae liquid of the photobioreactor 3 communicates with the inlet of the algae liquid of each flue gas treatment reactor 2-1 through the algae liquid direction pipe 5; liquid pump 7;

Each flue gas treatment reactor 2-1 and photobioreactor 3 are inoculated with an algae solution with an OD687 greater than 1.5; the algae solution is obtained by growing microalgae inoculated in a culture medium, and the culture medium is BG11 Base or domestic sewage after primary treatment; the pH of the culture medium=6~9, COD=100mg/L~400mg/L, TN=15mg/L~50mg/L, TP=2mg/L~10mg/L L;

The microalgae are Chlorella, Micromansella or Scenedesmus.

In this specific embodiment, the photobioreactor 3 is used as a bioreactor for flue gas treatment and microalgae cultivation. The flue gas treatment reactor 2-1 can be connected in different numbers according to factors such as flue gas concentration, treatment effect, and emission standards. The light source can be a natural light source or an artificial light source or a combination of both.

In this specific embodiment, the exhaust gas treated by the flue gas treatment reactor 2-1 is passed into another photobioreactor 3 for the cultivation of microalgae.

After the growth of microalgae in the photobioreactor 3 reaches a certain concentration, a part of them is introduced into the flue gas treatment reactor 2-1, and the remaining part is still used as algae-growing algae to supplement the domestic sewage and continue to culture. In such a cycle, the photobioreactor 3 provides sufficient algal sources for the flue gas treatment reactor 2-1, and the flue gas treatment reactor 2-1 provides relatively good flue gas conditions for algae cultivation.

Advantages of this specific embodiment: This specific embodiment relates to a microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and nutrient source, using _CO in the flue gas as a carbon source to realize flue gas denitrification New methods and systems. It mainly includes the following steps: use the domestic sewage that has undergone primary treatment as a culture solution, add algae, and cultivate under the conditions of light and CO ₂ until the microalgae reaches a certain concentration; then inoculate it into the flue gas treatment reactor 2-1 and photobioreactor 3, then use it as algae species for flue gas treatment, introduce flue gas from the outlet of desulfurization tower 8 from the bottom of flue gas treatment reactor 2-1, microalgae can use the CO ₂ grows as a carbon source and can use NO _X as a nitrogen source to achieve carbon fixation and denitrification of flue gas; the flue gas at the outlet of flue gas treatment reactor 2-1 is connected to photobioreactor 3 for microalgae cultivation At this time, the culture solution in the photobioreactor 3 is still domestic sewage after primary treatment; after the growth of microalgae in the flue gas treatment reactor 2-1 reaches a stable period, the biomass is collected for the extraction of biodiesel, and then The photobioreactor 3 is then used to provide sufficient algae species for the flue gas treatment reactor 2-1, and so on.

Using several strains of chlorella, micromansella or Scenedesmus obtained in the early stage that can tolerate actual sewage and actual smoke, apply the device of the present invention to actual sewage and simulated smoke, and use natural and artificial light sources to cultivate for seven days , the cell concentration can reach 2.0g/L-3.0g/L, the _CO2 fixation efficiency can reach 5%-20%, the _NOX removal rate can reach 20%-40%, and the oil content of harvested microalgae biomass is 15% to 25%, the nitrogen and phosphorus in the sewage are basically used up, and the removal rate is above 90%.

The device of this specific embodiment is used in field experiments of actual sewage and actual flue gas. After seven days of experiments, the concentration of microalgae cells can reach 1.5g/L～2.5g/L, and a single flue gas treatment reactor 2-1 can _The fixation rate of ₂ is between 5% and 15%, and the removal rate of NO _X is between 20% and 40% _. The removal rate of the algae can reach 30% to 80%, and the oil content of the finally collected algae cells is about 20%.

Thus, the removal efficiency of the whole system for _NOx in flue gas can reach 25%-80%, the fixation efficiency of _CO2 can reach 5%-30%, and the removal of nitrogen and phosphorus in sewage can also reach more than 90%. When the NO _X concentration in the flue gas at the inlet of the system is lower than 100 mg/m ³ , the outlet concentration is lower than 50 mg/m ³ , which can achieve ultra-low emission of NO _X in the flue gas, and at the same time make the nitrogen and phosphorus concentration in the wastewater reach the standard discharge . This device not only overcomes the problem of water source for microalgae cultivation in the process of microalgae flue gas denitrification, but also reduces the investment cost of microalgae system for flue gas denitrification, and finally can harvest a large amount of microalgae biomass that can be used as microalgae biodiesel The provision of raw materials is beneficial to the industrial application of microalgae for carbon fixation and denitrification of flue gas.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the gas direction pipe 4 and the algae liquid direction pipe 5 are silicone tubes. Others are the same as in the first embodiment.

Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that: the bottom of the flue gas treatment reactor 2-1 is provided with an aeration device; the bottom of the photobioreactor 3 is provided with There is an aeration device. Others are the same as in the first or second embodiment.

Embodiment 4: The difference between this embodiment and Embodiments 1 to 3 is that the flue gas treatment reactor 2-1 and photobioreactor 3 are plexiglass air-lift cylindrical photobioreactors. Others are the same as the specific embodiments 1 to 3.

Embodiment 5: The difference between this embodiment and Embodiment 1 to Embodiment 4 is that the gas flow controller 6 is an anti-corrosion gas flow meter. Others are the same as the specific embodiments 1 to 4.

Specific embodiment six: this embodiment is to use domestic sewage as a water source and nutrient source for microalgae flue gas carbon fixation and denitrification device. The method for flue gas carbon fixation and denitrification is carried out in the following steps:

1. Obtain microalgae:

First inoculate the microalgae into the culture medium, and then culture under the conditions of light, temperature 20°C-30°C and CO ₂ to obtain the algae liquid with OD687 greater than 1.5; the ventilation rate of CO ₂ during the culture process is 0.05vvm ～0.3vvm, the light intensity is 1000lux～3000lux, and the light time is 8h～12h per day;

The medium is BG11 medium or domestic sewage after primary treatment; the pH of the medium is 6-9, COD=100mg/L-400mg/L, TN=15mg/L-50mg/L, TP=2mg/L～10mg/L; The microalgae is Chlorella, Micromansella or Scenedesmus;

2. Flue gas treatment steps:

Inoculate the algae liquid with OD687 greater than 1.5 into each flue gas treatment reactor 2-1 and photobioreactor 3, connect the flue gas outlet of the desulfurization tower 8 with the inlet of the air pump 1, open the air pump 1, and Flue gas is introduced into the flue gas treatment system 2, the ventilation rate of the flue gas is controlled to be 0.05vvm~0.3vvm, and then the flue gas treatment of the flue gas treatment system 2 is carried out under the conditions of light and temperature of 20°C~30°C and algae cultivation in photobioreactor 3, the light intensity is 1000lux to 3000lux, and the light time is 8h to 12h per day. Add medium in 3 to ensure the growth of microalgae in the algae liquid of flue gas treatment reactor 2-1 and photobioreactor 3. When the OD687 of the algae liquid in flue gas treatment reactor 2-1 remains constant, the microalgae enter a stable period;

The medium is BG11 medium or domestic sewage after primary treatment; the pH of the medium is 6-9, COD=100mg/L-400mg/L, TN=15mg/L-50mg/L, TP=2mg/L～10mg/L; the algae liquid with OD687 greater than 1.5 accounts for 2/3 of the volume of flue gas treatment reactor 2-1 and photobioreactor 3 respectively;

3. Cyclic algae cultivation plus flue gas treatment:

①. Collect microalgae as raw materials for biodiesel or methane production by fermentation, open the pump 7, and feed algae liquid into each flue gas treatment reactor 2-1 to ensure that the algae in the flue gas treatment reactor 2-1 After the liquid OD687 is greater than 1.5, close the pump 7;

②. When the OD687 of the algae liquid in the flue gas treatment reactor 2-1 is constant, the growth of the microalgae enters a stable period. Repeat step 3 ① to complete the microalgae flue gas carbon fixation using domestic sewage as a water source and nutrient source. The denitrification device is used for the method of flue gas carbon fixation and denitrification.

Advantages of this specific embodiment: This specific embodiment relates to a microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and nutrient source, using _CO in the flue gas as a carbon source to realize flue gas denitrification New methods and systems. It mainly includes the following steps: use the domestic sewage that has undergone primary treatment as a culture solution, add algae, and cultivate under the conditions of light and CO ₂ until the microalgae reaches a certain concentration; then inoculate it into the flue gas treatment reactor 2-1 and photobioreactor 3, then use it as algae species for flue gas treatment, introduce flue gas from the outlet of desulfurization tower 8 from the bottom of flue gas treatment reactor 2-1, microalgae can use the CO ₂ grows as a carbon source and can use NO _X as a nitrogen source to achieve carbon fixation and denitrification of flue gas; the flue gas at the outlet of flue gas treatment reactor 2-1 is connected to photobioreactor 3 for microalgae cultivation At this time, the culture solution in the photobioreactor 3 is still domestic sewage after primary treatment; after the growth of microalgae in the flue gas treatment reactor 2-1 reaches a stable period, the biomass is collected for the extraction of biodiesel, and then The photobioreactor 3 is then used to provide sufficient algae species for the flue gas treatment reactor 2-1, and so on.

Using several strains of chlorella, micromansella or Scenedesmus obtained in the early stage that can tolerate actual sewage and actual smoke, apply the device of the present invention to actual sewage and simulated smoke, and use natural and artificial light sources to cultivate for seven days , the cell concentration can reach 2.0g/L-3.0g/L, the _CO2 fixation efficiency can reach 5%-20%, the _NOX removal rate can reach 20%-40%, and the oil content of harvested microalgae biomass is 15% to 25%, the nitrogen and phosphorus in the sewage are basically used up, and the removal rate is above 90%.

The device of this specific embodiment is used in field experiments of actual sewage and actual flue gas. After seven days of experiments, the concentration of microalgae cells can reach 1.5g/L～2.5g/L, and a single flue gas treatment reactor 2-1 can _The fixation rate of ₂ is between 5% and 15%, and the removal rate of NO _X is between 20% and 40% _. The removal rate of the algae can reach 30% to 80%, and the oil content of the finally collected algae cells is about 20%.

Thus, the removal efficiency of the whole system for _NOx in flue gas can reach 25%-80%, the fixation efficiency of _CO2 can reach 5%-30%, and the removal of nitrogen and phosphorus in sewage can also reach more than 90%. When the NO _X concentration in the flue gas at the inlet of the system is lower than 100 mg/m ³ , the outlet concentration is lower than 50 mg/m ³ , which can achieve ultra-low emission of NO _X in the flue gas, and at the same time make the nitrogen and phosphorus concentration in the wastewater reach the standard discharge . This device not only overcomes the problem of water source for microalgae cultivation in the process of microalgae flue gas denitrification, but also reduces the investment cost of microalgae system for flue gas denitrification, and finally can harvest a large amount of microalgae biomass that can be used as microalgae biodiesel The provision of raw materials is beneficial to the industrial application of microalgae for carbon fixation and denitrification of flue gas.

Embodiment 7: The difference between this embodiment and Embodiment 6 is that the illumination in step 1 is a combination of one or both of natural light sources and artificial light sources. Others are the same as in the sixth embodiment.

Embodiment 8: The difference between this embodiment and Embodiment 6 or 7 is that the illumination described in step 2 is a combination of one or both of natural light sources and artificial light sources. Others are the same as in Embodiment 6 or 7.

Embodiment 9: This embodiment differs from Embodiment 6 to Embodiment 8 in that: in step 2, the ventilation rate of flue gas is controlled to be 0.1vvm. Others are the same as the sixth to eighth specific embodiments.

Embodiment 10: The difference between this embodiment and one of Embodiments 6 to 9 is that in step 2, the flue gas treatment and photobiological reaction of the flue gas treatment system 2 are carried out under the conditions of light and temperature of 25°C For algae cultivation in device 3, the light intensity is 1000 lux to 3000 lux, and the light time is 10 hours per day. Others are the same as the sixth to ninth embodiments.

Adopt the following examples to verify the effect of the present invention:

Embodiment one:

The microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and nutrient source consists of an air pump 1, a flue gas treatment system 2, a photobioreactor 3, a gas direction pipe 4, an algae liquid direction pipe 5, and a gas flow controller 6 and liquid suction pump 7;

The flue gas treatment system 2 is composed of a flue gas treatment reactor 2-1;

The flue gas treatment reactor 2-1 is an air-lift cylindrical photobioreactor, and the aspect ratio of the flue gas treatment reactor 2-1 is 15:1; and the lower part of the flue gas treatment reactor 2-1 is respectively There is a flue gas inlet, and the upper part is equipped with a flue gas outlet and an algae liquid inlet;

The photobioreactor 3 is an air-lift cylindrical photobioreactor, and the height-to-diameter ratio of the photobioreactor 3 is 15:1; and the bottom of the photobioreactor 3 is provided with a flue gas inlet and an algal liquid outlet , the upper part is provided with a flue gas outlet;

The outlet of the exhaust pump 1 is connected to the flue gas inlet of the flue gas treatment system 2 through the gas direction pipe 4, and the flue gas outlet of the flue gas treatment system 2 is connected to the flue gas inlet of the photobioreactor 3 through the gas direction pipe 4; And a gas flow controller 6 is provided between the air extraction pump 1 and the flue gas treatment system 2;

The outlet of the algae liquid of the photobioreactor 3 communicates with the inlet of the algae liquid of each flue gas treatment reactor 2-1 through the algae liquid direction pipe 5; liquid pump 7;

Each flue gas treatment reactor 2-1 and photobioreactor 3 are inoculated with algae liquid with OD687 of 3.0; Domestic sewage after grade treatment; Described culture medium pH=7.9, COD=378mg/L, TN=47mg/L, TP=5.1mg/L;

The microalgae is Micractinium sp.;

The gas direction pipe 4 and the algae liquid direction pipe 5 are silica gel tubes;

The bottom of the flue gas treatment reactor 2-1 is provided with an aeration device;

The bottom of the photobioreactor 3 is provided with an aeration device;

The flue gas treatment reactor 2-1 and photobioreactor 3 are plexiglass airlift cylindrical photobioreactors;

The gas flow controller 6 is an anti-corrosion gas flow meter;

The method for using the microalgae flue gas carbon fixation denitrification device using domestic sewage as a water source and nutrient source for flue gas carbon fixation denitrification is carried out according to the following steps:

1. Obtain microalgae:

First inoculate the microalgae in the culture medium, then culture under the condition of light, temperature of 25°C and CO ₂ to obtain the algae liquid with OD687 of 3.0; the ventilation rate of CO ₂ during the culture is 0.1vvm, and the light intensity 1000lux ~ 3000lux, the light time is 8h ~ 12h per day;

The medium is domestic sewage after primary treatment; the medium pH=7.9, COD=378mg/L, TN=47mg/L, TP=5.1mg/L; the microalgae are microalgae Micractinium sp.;

2. Flue gas treatment steps:

Inoculate the algae liquid with OD687 of 3.0 into each flue gas treatment reactor 2-1 and photobioreactor 3, connect the flue gas outlet of the simulated flue gas with the inlet of the suction pump 1, turn on the suction pump 1, and Flue gas is introduced into the flue gas treatment system 2, and the ventilation rate of the flue gas is controlled to be 0.1vvm, and then the flue gas treatment of the flue gas treatment system 2 and the photobioreactor 3 are carried out under the conditions of light and temperature of 25°C The light intensity is 1000lux～3000lux, the light time is 12h per day, and the medium is added to the flue gas treatment reactor 2-1 and the photobioreactor 3 respectively during the flue gas treatment and algae cultivation process to ensure The microalgae grow in the algae liquid in the flue gas treatment reactor 2-1 and the photobioreactor 3, and when the OD687 of the algae liquid in the flue gas treatment reactor 2-1 remains constant, the growth of the microalgae enters a stable period;

The medium is domestic sewage after primary treatment; the medium pH=7.9, COD=378mg/L, TN=47mg/L, TP=5.1mg/L; the OD687 is greater than 1.5 The algae liquid accounts for 2/3 of the volume of the flue gas treatment reactor 2-1 and the photobioreactor 3 respectively;

3. Cyclic algae cultivation plus flue gas treatment:

①. Collect microalgae as raw materials for biodiesel or methane production by fermentation, open the pump 7, and feed algae liquid into each flue gas treatment reactor 2-1 to ensure that the algae in the flue gas treatment reactor 2-1 After the liquid OD687 is greater than 1.5, close the pump 7;

②. When the OD687 of the algae liquid in the flue gas treatment reactor 2-1 is constant, the growth of the microalgae enters a stable period. Repeat step 3 ① to complete the microalgae flue gas carbon fixation using domestic sewage as a water source and nutrient source. The denitrification device is used for the method of flue gas carbon fixation and denitrification;

The illumination described in step 1 is natural illumination; the illumination described in step 2 is natural illumination;

The volume concentration of CO ₂ in the simulated flue gas described in step 2 is 10%, and the volume concentration of NO _X in the simulated flue gas is 75ppm.

Within a seven-day cycle, the CO ₂ fixation rate is 8.5%, the NO _X removal rate is 35%, and the nitrogen and phosphorus removal in sewage can also reach 97%. The finally obtained algal cell density is 2.3g/L, and the algal cell oil content is 17%.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the microalgae is Chlorella sp. Others are the same as in Embodiment 1.

Within a seven-day cycle, the CO ₂ fixation rate is about 15%, the NO _X removal rate is about 28%, and the nitrogen and phosphorus removal in sewage can also reach 95%. The finally obtained algal cell density is 2.6g/L, and the algal cell oil content is 19%.

Embodiment 3: The difference between this embodiment and Embodiment 1 is that the microalgae is Chlorellasorokiniana. Others are the same as in Embodiment 1.

Within a seven-day cycle, the _CO2 fixation rate is about 12%, the _NOX removal rate is about 25%, and the nitrogen and phosphorus removal in sewage can also reach 93%. The finally obtained algal cell density is 2.4g/L, and the algal cell oil content is 21%.

Embodiment 4: The difference between this embodiment and Embodiment 1 is that: the illumination described in step 1 is a combination of natural light source and artificial light source; the illumination described in step 2 is a combination of natural light source and artificial light source. Others are the same as in Embodiment 1.

The fixation rate of CO ₂ is about 17%, the removal rate of NO _X is about 37%, and the removal of nitrogen and phosphorus in sewage can also reach 97% within a seven-day cycle. The finally obtained algae density is 2.8g/L, and the oil content of algae cells is 17%.

Embodiment 5: The difference between this embodiment and Embodiment 1 is that: the height-to-diameter ratio of the flue gas treatment reactor 2-1 is 10:1; the height-to-diameter ratio of the photobioreactor 3 is 10 :1. Others are the same as in Embodiment 1.

Within a seven-day cycle, the CO ₂ fixation rate is about 7.5%, the NO _X removal rate is about 30%, and the nitrogen and phosphorus removal in sewage can also reach 97%. The finally obtained algal density was 2.1g/L, and the cell oil content was 16%.

Embodiment six:

The microalgae flue gas carbon fixation and denitrification device using domestic sewage as a water source and nutrient source consists of an air pump 1, a flue gas treatment system 2, a photobioreactor 3, a gas direction pipe 4, an algae liquid direction pipe 5, and a gas flow controller 6 and liquid suction pump 7;

The flue gas treatment system 2 is composed of a flue gas treatment reactor 2-1;

The flue gas treatment reactor 2-1 is an air-lift cylindrical photobioreactor, and the aspect ratio of the flue gas treatment reactor 2-1 is 15:1; and the lower part of the flue gas treatment reactor 2-1 is respectively There is a flue gas inlet, and the upper part is equipped with a flue gas outlet and an algae liquid inlet;

The photobioreactor 3 is an air-lift cylindrical photobioreactor, and the height-to-diameter ratio of the photobioreactor 3 is 15:1; and the bottom of the photobioreactor 3 is provided with a flue gas inlet and an algal liquid outlet , the upper part is provided with a flue gas outlet;

The outlet of the exhaust pump 1 is connected to the flue gas inlet of the flue gas treatment system 2 through the gas direction pipe 4, and the flue gas outlet of the flue gas treatment system 2 is connected to the flue gas inlet of the photobioreactor 3 through the gas direction pipe 4; And a gas flow controller 6 is provided between the air extraction pump 1 and the flue gas treatment system 2;

The outlet of the algae liquid of the photobioreactor 3 communicates with the inlet of the algae liquid of each flue gas treatment reactor 2-1 through the algae liquid direction pipe 5; liquid pump 7;

Each flue gas treatment reactor 2-1 and photobioreactor 3 are inoculated with algae liquid with OD687 of 3.0; Domestic sewage after grade treatment; Described culture medium pH=7.7, COD=287mg/L, TN=44mg/L, TP=4.7mg/L;

The microalgae is Micractinium sp.;

The gas direction pipe 4 and the algae liquid direction pipe 5 are silica gel tubes;

The bottom of the flue gas treatment reactor 2-1 is provided with an aeration device;

The bottom of the photobioreactor 3 is provided with an aeration device;

The flue gas treatment reactor 2-1 and photobioreactor 3 are plexiglass airlift cylindrical photobioreactors;

The gas flow controller 6 is an anti-corrosion gas flowmeter;

The method for using the microalgae flue gas carbon fixation denitrification device using domestic sewage as a water source and nutrient source for flue gas carbon fixation denitrification is carried out according to the following steps:

1. Obtain microalgae:

First inoculate the microalgae in the culture medium, then culture under the condition of light, temperature of 25°C and CO ₂ to obtain the algae liquid with OD687 of 3.0; the ventilation rate of CO ₂ during the culture is 0.1vvm, and the light intensity 1000lux ~ 3000lux, the light time is 12h per day;

The medium is domestic sewage after primary treatment; the medium pH=7.7, COD=287mg/L, TN=44mg/L, TP=4.7mg/L; the microalgae are microalgae Micractinium sp.;

2. Flue gas treatment steps:

Inoculate the algae liquid with OD687 of 3.0 into each flue gas treatment reactor 2-1 and photobioreactor 3, connect the flue gas outlet of the power plant site desulfurization tower 8 with the inlet of the air pump 1, and turn on the air pump 1 , feed the flue gas into the flue gas treatment system 2, control the ventilation rate of the flue gas to 0.1vvm, and then carry out the flue gas treatment and For algae cultivation in photobioreactor 3, the light intensity is 1000lux to 3000lux, and the light time is 12h per day, and the flue gas treatment reactor 2-1 and photobioreactor 3 are supplied with Enter the culture medium to ensure the growth of microalgae in the algae liquid in the flue gas treatment reactor 2-1 and photobioreactor 3. When the OD687 of the algae liquid in the flue gas treatment reactor 2-1 remains constant, the growth of the microalgae enters a stable period , collecting microalgae as raw materials for biodiesel or methane production by fermentation;

The medium is domestic sewage after primary treatment; the medium pH=7.6, COD=267mg/L, TN=39mg/L, TP=4.9mg/L; the OD687 is greater than 1.5 The algae liquid accounts for 2/3 of the volume of the flue gas treatment reactor 2-1 and the photobioreactor 3 respectively;

3. Cyclic algae cultivation plus flue gas treatment:

①. Collect the microalgae as raw material for biodiesel or methane production by fermentation, turn on the liquid pump 7, and feed the algae liquid into the flue gas treatment reactor 2-1 to ensure the OD687 of the algae liquid in the flue gas treatment reactor 2-1 After greater than 1.5, close the suction pump 7;

②. When the OD687 of the algae liquid in the flue gas treatment reactor 2-1 is constant, the growth of the microalgae enters a stable period. Repeat step 3 ① to complete the microalgae flue gas carbon fixation using domestic sewage as a water source and nutrient source. The denitrification device is used for the method of flue gas carbon fixation and denitrification;

The illumination described in step 1 is natural illumination; the illumination described in step 2 is natural illumination;

The volume concentration of _CO in the actual flue gas produced by the flue gas outlet of the on-site desulfurization tower 8 of the power plant described in step 2 is 10% to 15%. The volume concentration of NO _X is 20ppm-50ppm.

In a seven-day cycle, the removal rate of microalgae to _CO2 is 8%-12%. When the _CO2 concentration at the inlet of the reactor is 10%, the removal rate can reach 12%, and the removal rate can reach 15% when the inlet _CO2 concentration is 15%. 8%. The removal rate of NO by microalgae is 27%-38%. When the NO concentration at the reactor inlet is 20ppm, the NO removal rate can reach 38%. When the reactor inlet NO concentration is 50ppm, the NO removal rate is 27%. The cell density of the final harvested algae was 1.9g/L, and the cell oil content was 15%.

Embodiment 7: The difference between this embodiment and Embodiment 6 is that the microalgae is Chlorella sp. Others are the same as in Embodiment six.

In a seven-day period, the removal rate of _CO2 by microalgae is ₁₀ %-15%. When the _CO2 concentration at the inlet of the reactor is 10%, the removal rate can reach 15%. 10%. The removal rate of NO by microalgae is 20%-32%. When the NO concentration at the reactor inlet is 20ppm, the NO removal rate can reach 32%. When the reactor inlet NO concentration is 50ppm, the NO removal rate is 20%. The cell density of the final harvested algae was 1.7g/L, and the cell oil content was 17%.

Embodiment 8: The difference between this embodiment and Embodiment 6 is that the microalgae is Chlorellasorokiniana. Others are the same as in Embodiment six.

In a seven-day period, the removal rate of _CO2 by microalgae is 12%-15%. When the _CO2 concentration at the inlet of the reactor is 10%, the removal rate can reach 15%, and the removal rate can reach 15% when the inlet _CO2 concentration is 15%. 12%. The removal rate of NO by microalgae is 20%-29%. When the NO concentration at the reactor inlet is 20ppm, the NO removal rate can reach 29%. When the reactor inlet NO concentration is 50ppm, the NO removal rate is 20%. The cell density of the final harvested algae was 2.3g/L, and the cell oil content was 19%.

Embodiment 9: The difference between this embodiment and Embodiment 6 is that the illumination described in step 1 is a combination of natural light source and artificial light source; the illumination described in step 2 is a combination of natural light source and artificial light source. Others are the same as in Embodiment six.

In a seven-day period, the removal rate of _CO2 by microalgae is 10%-13%. When the _CO2 concentration at the inlet of the reactor is 10%, the removal rate can reach 13%, and the removal rate can reach 15% when the inlet _CO2 concentration is 15%. 10%. The removal rate of NO by microalgae is 27%-40%. When the NO concentration at the reactor inlet is 20ppm, the NO removal rate can reach 40%. When the reactor inlet NO concentration is 50ppm, the NO removal rate is 27%. The cell density of the final harvested algae was 2.3g/L, and the cell oil content was 16%.

Embodiment 10: The difference between this embodiment and Embodiment 6 is that: the height-to-diameter ratio of the flue gas treatment reactor 2-1 is 10:1; the height-to-diameter ratio of the photobioreactor 3 is 10 :1. Others are the same as in Embodiment six.

In a seven-day period, the removal rate of _CO2 by microalgae is 8%-10%. When the _CO2 concentration at the inlet of the reactor is 10%, the removal rate can reach 10%, and the removal rate can reach 15% when the inlet _CO2 concentration is 15%. 8%. The removal rate of NO by microalgae is 20%-30%. When the NO concentration at the reactor inlet is 20ppm, the NO removal rate can reach 30%. When the reactor inlet NO concentration is 50ppm, the NO removal rate is 20%. The cell density of the final harvested algae was 1.7g/L, and the cell oil content was 15%.

Embodiment 11: The difference between this embodiment and Embodiment 6 is that the flue gas treatment system 2 is composed of two flue gas treatment reactors 2-1 connected in series. Others are the same as in Embodiment six.

In a seven-day period, the removal rate of CO ₂ by microalgae is 20%-25%. When the CO ₂ concentration at the inlet of the reactor is 10%, the removal rate can reach 25%, and the removal rate can reach 15% when the inlet CO ₂ concentration is 15%. 20%. The removal rate of NO by microalgae is 60%-77%. When the NO concentration at the reactor inlet is 20ppm, the NO removal rate can reach 77%. When the reactor inlet NO concentration is 50ppm, the NO removal rate is 60%. The cell density of the final harvested algae was 1.8g/L, and the cell oil content was 17%.

Example 12: The difference between this embodiment and Example 6 is that: the flue gas treatment system 2 is composed of two flue gas treatment reactors 2-1 connected in series; the flue gas treatment reactor 2-1 The aspect ratio of the photobioreactor 3 is 10:1; the aspect ratio of the photobioreactor 3 is 10:1. Others are the same as in Embodiment six.

In a seven-day period, the removal rate of CO ₂ by microalgae is 17%-21%. When the CO ₂ concentration at the inlet of the reactor is 10%, the removal rate can reach 21%, and the removal rate can reach 15% when the inlet CO ₂ concentration is 15%. 17%. The removal rate of NO by microalgae is 55%-67%. When the NO concentration at the reactor inlet is 20ppm, the NO removal rate can reach 67%. When the reactor inlet NO concentration is 50ppm, the NO removal rate is 55%. The cell density of the final harvested algae was 1.7g/L, and the cell oil content was 18%.

Claims (10)

1. The microalgae flue gas carbon fixation denitrification device using domestic sewage as a water source and nutrient source is characterized in that: the microalgae flue gas carbon fixation denitrification device using domestic sewage as a water source and a nutrient source consists of an air pump (1), Flue gas treatment system (2), photobioreactor (3), gas direction pipe (4), algae liquid direction pipe (5), gas flow controller (6) and liquid pump (7); The flue gas treatment system (2) is composed of a flue gas treatment reactor (2-1); Or the flue gas treatment system (2) is composed of two or more flue gas treatment reactors (2-1) connected in series; The flue gas treatment reactor (2-1) is an air-lift cylindrical photobioreactor, and the aspect ratio of the flue gas treatment reactor (2-1) is (10-20):1; and the flue gas treatment The lower part of the reactor (2-1) is provided with a flue gas inlet, and the upper part is provided with a flue gas outlet and an algae liquid inlet; The photobioreactor (3) is an airlift cylindrical photobioreactor, and the aspect ratio of the photobioreactor (3) is (10～20):1; and the lower part of the photobioreactor (3) There are flue gas inlets and algae liquid outlets respectively, and the upper part is equipped with flue gas outlets; The outlet of the air extraction pump (1) is connected to the flue gas inlet of the flue gas treatment system (2) through the gas direction pipe (4), and the flue gas outlet of the flue gas treatment system (2) is connected to the photobiological system through the gas direction pipe (4). The flue gas inlet of the reactor (3) is connected; and a gas flow controller (6) is provided between the air extraction pump (1) and the flue gas treatment system (2); The algae liquid outlet of the photobioreactor (3) is connected with the algae liquid inlet of each flue gas treatment reactor (2-1) through the algae liquid going pipe (5); and the photobioreactor (3) is connected with the flue gas A liquid suction pump (7) is arranged between the treatment systems (2); Each flue gas treatment reactor (2-1) and photobioreactor (3) are inoculated with algae liquid with OD687 greater than 1.5; The base is BG11 medium or domestic sewage after primary treatment; the pH of the medium is 6-9, COD=100mg/L-400mg/L, TN=15mg/L-50mg/L, TP=2mg/L L～10mg/L; The microalgae are Chlorella, Micromansella or Scenedesmus. 2. The microalgae flue gas-fixing carbon denitrification device using domestic sewage as a water source and nutrient source according to claim 1, characterized in that: the gas direction pipe (4) and the algae liquid direction pipe (5) are Silicone tubing. 3. The microalgae flue gas-fixed carbon denitrification device using domestic sewage as water source and nutrient source according to claim 1, characterized in that: the bottom of the flue gas treatment reactor (2-1) is provided with aeration device; the bottom of the photobioreactor (3) is provided with an aeration device. 4. The microalgae flue gas-fixed carbon denitrification device utilizing domestic sewage as water source and nutrient source according to claim 1, characterized in that: described flue gas treatment reactor (2-1) and photobioreactor (3) is a plexiglass airlift cylindrical photobioreactor. 5. The microalgae flue gas fixation carbon denitrification device using domestic sewage as water source and nutrient source according to claim 1, characterized in that: the gas flow controller (6) is an anti-corrosion gas flow meter. 6. as claimed in claim 1, the microalgae flue gas carbon fixation denitrification device utilizing domestic sewage as water source and nutrient source is used for the method of flue gas carbon fixation denitrification, it is characterized in that utilizing domestic sewage as water source and nutrient source The method of microalgae flue gas carbon fixation and denitrification device for flue gas carbon fixation and denitrification is carried out in the following steps: 1. Obtain microalgae: First inoculate the microalgae into the culture medium, and then culture under the conditions of light, temperature 20°C-30°C and CO ₂ to obtain the algae liquid with OD687 greater than 1.5; the ventilation rate of CO ₂ during the culture process is 0.05vvm ～0.3vvm, the light intensity is 1000lux～3000lux, and the light time is 8h～12h per day; The medium is BG11 medium or domestic sewage after primary treatment; the pH of the medium is 6-9, COD=100mg/L-400mg/L, TN=15mg/L-50mg/L, TP=2mg/L～10mg/L; The microalgae is Chlorella, Micromansella or Scenedesmus; 2. Flue gas treatment steps: Inoculate the algae liquid with OD687 greater than 1.5 into each flue gas treatment reactor (2-1) and photobioreactor (3), and connect the flue gas outlet of the desulfurization tower (8) with the inlet of the air pump (1) Turn on the exhaust pump (1), feed the flue gas into the flue gas treatment system (2), control the ventilation rate of the flue gas to 0.05vvm ~ 0.3vvm, and then the The flue gas treatment of the flue gas treatment system (2) and the algae cultivation of the photobioreactor (3) are carried out under the conditions, the light intensity is 1000lux to 3000lux, the light time is 8h to 12h per day, and the flue gas treatment and algae cultivation process Add culture medium to flue gas treatment reactor (2-1) and photobioreactor (3) respectively, to ensure flue gas treatment reactor (2-1) and photobioreactor (3) Algae growth, when the OD687 of the algae liquid in the flue gas treatment reactor (2-1) remains constant, the growth of the microalgae enters a stable period; The medium is BG11 medium or domestic sewage after primary treatment; the pH of the medium is 6-9, COD=100mg/L-400mg/L, TN=15mg/L-50mg/L, TP=2mg/L～10mg/L; the algae liquid with OD687 greater than 1.5 accounts for 2/3 of the volume of the flue gas treatment reactor (2-1) and photobioreactor (3); 3. Cyclic algae cultivation plus flue gas treatment: ①. Collect the microalgae as raw material for biodiesel or methane production by fermentation, open the liquid pump (7), and feed the algae liquid into each flue gas treatment reactor (2-1) to ensure that the flue gas treatment reactor (2-1) 2-1) After the algae liquid OD687 is greater than 1.5, close the pump (7); ②. When the OD687 of the algae liquid in the flue gas treatment reactor (2-1) remains constant, the growth of microalgae enters a stable period. Repeat step 3. ①, that is, the microalgae flue gas production using domestic sewage as a water source and nutrient source is completed. The carbon fixation and denitrification device is used for the method of flue gas carbon fixation and denitrification. 7. the microalga flue gas carbon fixation denitrification device utilizing domestic sewage as water source and nutrient source according to claim 6 is used for the method for flue gas carbon fixation denitrification, it is characterized in that: the illumination described in step 1 is A combination of one or both of natural and artificial light sources. 8. the microalgae flue gas carbon fixation denitrification device utilizing domestic sewage as water source and nutrient source according to claim 6 is used for the method for flue gas carbon fixation denitrification, it is characterized in that: the illumination described in step 2 is A combination of one or both of natural and artificial light sources. 9. the microalgae flue gas carbon fixation denitrification device utilizing domestic sewage as water source and nutrient source according to claim 6 is used for the method for flue gas carbon fixation denitrification, it is characterized in that: in the step 2, control flue gas The ventilation rate is 0.1vvm. 10. The microalgae flue gas carbon fixation denitrification device utilizing domestic sewage as water source and nutrient source according to claim 6 is used for the method for flue gas carbon fixation denitrification, characterized in that: in step 2, then under light and temperature The flue gas treatment of the flue gas treatment system (2) and the algae cultivation of the photobioreactor (3) are carried out under the condition of 25° C., the light intensity is 1000 lux to 3000 lux, and the light time is 10 hours per day.