阅读说明：本技术 一种基于水相养藻的污泥和微藻超临界共快速水热液化制油系统及工艺 (Sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system and process based on water-phase algae cultivation ) 是由 钱黎黎 倪俊 王爽 胡亚敏 罗明 于 2021-01-05 设计创作，主要内容包括：本发明提供了一种基于水相养藻的污泥和微藻超临界共快速水热液化制油系统及工艺,包括原料输运单元、预热反应单元、降温降压单元、产物分离单元、油相提质单元、微藻培育单元；所述微藻培育单元用于培育微藻；所述原料输运单元用于将微藻和污泥进行缓冲、除铁、研磨和均质后输入预热反应单元,经过高频电磁感应加热器后进入超临界快速水热液化反应器,输出水热产物；所述降温降压单元通过有机工质朗肯循环装置回收余热；水热产物经所述产物分离单元离心分离为水相产物、固相产物和油相产物；所述油相产物通过油相提质单元转变为生物燃油。本发明通过快速预热、超临界快速水热和共液化技术提高了污泥和微藻的产油率,实现了水相产物的循环利用。(The invention provides a supercritical co-rapid hydrothermal liquefaction oil production system and process for sludge and microalgae based on water-phase algae cultivation, which comprises a raw material conveying unit, a preheating reaction unit, a cooling and depressurizing unit, a product separation unit, an oil phase upgrading unit and a microalgae cultivation unit; the microalgae cultivating unit is used for cultivating microalgae; the raw material conveying unit is used for buffering, deironing, grinding and homogenizing the microalgae and the sludge, inputting the microalgae and the sludge into the preheating reaction unit, passing through the high-frequency electromagnetic induction heater, then entering the supercritical rapid hydrothermal liquefaction reactor, and outputting a hydrothermal product; the cooling and depressurizing unit recovers waste heat through an organic working medium Rankine cycle device; the hydrothermal product is centrifugally separated into a water phase product, a solid phase product and an oil phase product by the product separation unit; the oil phase product is converted into the biofuel oil through an oil phase upgrading unit. The invention improves the oil yield of the sludge and the microalgae by the rapid preheating, supercritical rapid hydrothermal and co-liquefaction technologies and realizes the recycling of water phase products.)

1. A supercritical co-rapid hydrothermal liquefaction oil production system for sludge and microalgae based on water-phase algae cultivation is characterized by comprising a raw material conveying unit, a preheating reaction unit, a cooling and depressurizing unit, a product separation unit, an oil-phase upgrading unit and a microalgae cultivation unit;

the microalgae cultivating unit is used for cultivating microalgae; the raw material conveying unit comprises a buffer pool (1), an iron remover (2), a grinding pump (3), a homogenizing tank (4) and a diaphragm pump (5) which are sequentially connected in series according to the flow direction, the microalgae and the sludge are respectively input into the buffer pool (1) to be mixed, and the raw material conveying unit is used for inputting the mixture into the preheating reaction unit after iron removal, grinding and homogenization;

the preheating reaction unit comprises a high-frequency electromagnetic induction heater (6) and a supercritical rapid hydrothermal liquefaction reactor (7), the high-frequency electromagnetic induction heater (6) is used for preheating the mixture and conveying the mixture to the supercritical rapid hydrothermal liquefaction reactor (7), and the supercritical rapid hydrothermal liquefaction reactor (7) outputs hydrothermal products through supercritical co-rapid hydrothermal liquefaction reaction;

the temperature and pressure reduction unit is used for reducing the temperature and the pressure of the hydrothermal product; the temperature and pressure reduction unit is communicated with the product separation unit, and the product separation unit converts the hydrothermal product into a water phase product (11), a solid phase product (12) and an oil phase product (13) through centrifugal separation (10); the oil phase product (13) is converted to biofuel by the oil phase upgrading unit by means of hydro upgrading (14).

2. The system for supercritical co-rapid hydrothermal liquefaction of oil production from sludge and microalgae based on aqueous algae cultivation according to claim 1, characterized in that the aqueous phase product (11) is fed into a homogenization tank (4) for dilution of the mixture; the water phase product (11) is input into an oil phase upgrading unit and is used for providing a hydrogen source for the oil phase product (13); the aqueous phase product (11) is fed to a microalgae cultivation unit for providing a nutrient source for cultivating microalgae.

3. The supercritical co-rapid hydrothermal liquefaction oil production system for sludge and microalgae based on water-phase algae cultivation according to claim 1, characterized in that the temperature and pressure reduction unit comprises an organic working medium Rankine cycle device (8) and a pressure reduction device (9), wherein the organic working medium Rankine cycle device (8) is used for reducing the temperature of the hydrothermal product and converting the heat energy of the hydrothermal product into electric energy; the pressure reduction device (9) is used for reducing the pressure of the hydrothermal product.

4. The supercritical co-rapid hydrothermal liquefaction oil production system based on sludge and microalgae obtained by water-phase algae cultivation according to claim 3, characterized in that the pressure reduction device (9) is a backpressure valve when the solid content of the mixture of sludge and microalgae at the outlet of the buffer tank (1) is less than 5 wt%; when the solid content of the mixture of the sludge and the microalgae at the outlet of the buffer tank (1) is more than or equal to 5 wt%, the pressure reduction device (9) is a capillary pressure reduction device.

5. The supercritical co-rapid hydrothermal liquefaction oil production system for sludge and microalgae based on aqueous algae cultivation according to claim 1, wherein the microalgae cultivation unit comprises a photobioreactor (16), a collector (17) and a drying device (18), and algae seeds enter the photobioreactor (16) after being inoculated (15) for cultivating microalgae; the microalgae are transported into a buffer pool (1) through a collector (17) and a drying device (18); the aqueous phase product (11) is fed into a photobioreactor (16) for providing a nutrient source for cultivating microalgae, and the microalgae can be used for adsorbing heavy metal ions in the aqueous phase product (11).

6. The oil production process of the water-phase algae-culturing sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system according to claim 1, characterized by comprising the following steps:

culturing microalgae through the microalgae culturing unit, respectively inputting the microalgae and sludge into the buffer pool (1) for mixing, sequentially inputting the mixture into the iron remover (2), the grinding pump (3), the homogenizing tank (4) and the diaphragm pump (5), and removing ferromagnetic impurities in the mixture through the iron remover (2); chopping large insoluble solids in the mixture by means of a grinding pump (3); diluting the mixture through the homogenization tank (4) for reducing the viscosity of the mixture; the mixture is input into the inlet end of the preheating reaction unit through a diaphragm pump (5);

the sludge and microalgae mixture at the outlet of the raw material conveying unit is input into a high-frequency electromagnetic induction heater (6), the mixture is preheated by the high-frequency electromagnetic induction heater (6) to a temperature above the critical temperature of water, and the preheated mixture enters a supercritical rapid hydrothermal liquefaction reactor (7) and outputs a hydrothermal product through a supercritical co-rapid hydrothermal liquefaction reaction;

the hydrothermal product is cooled after passing through an organic working medium Rankine cycle device (8); the cooled hydrothermal product is depressurized by a depressurization device (9);

the reduced hydrothermal product is converted into an aqueous phase product (11), a solid phase product (12) and an oil phase product (13) through centrifugal separation (10), wherein the solid phase product (12) can fix heavy metals; the water phase product (11) provides a nutrient source required by growth for the microalgae in the photobioreactor (16), heavy metal ions in the water phase product (11) are adsorbed by the microalgae, and the chemical oxygen demand, total nitrogen and total phosphorus content of the water phase product (11) are reduced;

the oil phase product (13) is used for obtaining the biofuel oil through hydrogenation upgrading (14), and the water phase product (11) can provide hydrogen elements required by the hydrogenation upgrading (14).

7. The oil production process of the water-phase algae-raising-based sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system according to claim 6, wherein the reaction temperature of the supercritical rapid hydrothermal liquefaction reactor (7) is 400-600 ℃, and the reaction time is less than 5 min.

8. The oil production process of the water-phase algae-raising sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system according to claim 6, characterized in that the particle size of insoluble solid particles in the mixture output by the grinding pump (3) is less than 50 μm.

9. The oil production process of the water-phase algae-raising-based sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system according to claim 6, wherein the temperature rise rate of the high-frequency electromagnetic induction heater (6) is greater than 100 ℃ min^-1。

10. The oil production process of the water-phase algae-raising-based sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system according to claim 6, characterized in that the organic working medium Rankine cycle device (8) generates electric energy by cooling hydrothermal products, and the electric energy is provided for the high-frequency electromagnetic induction heater (6).

Technical Field

The invention relates to the field of biomass thermochemical conversion, the field of sludge treatment or the field of environmental protection, in particular to a supercritical co-rapid hydrothermal liquefaction oil preparation system and process for sludge and microalgae based on water-phase algae cultivation.

Background

The sludge is a byproduct in the town sewage treatment process, and has the advantages of high yield, high speed increasing speed, high water content, difficult removal of water, high organic matter content, heavy metal and difficult-degradation toxic pollutants. The heavy metal and NO exist in the traditional treatment method (landfill, composting, incineration and the like) of the municipal sludge_xAnd dioxin and the like, and mechanical dewatered sludge needs to be further dried to reduce the water content, and the treatment cost of the sludge can account for more than 50 percent of the operation cost of a sewage treatment plant due to high drying cost.

The hydrothermal liquefaction technology is a process of converting biomass into oily liquid organic micromolecules through depolymerization, bond breaking, rearrangement, decarboxylation and other reactions under the conditions of high temperature and higher than the saturation pressure of water, and liquid fuel produced by separation is called biological crude oil. Compared with the traditional sludge treatment technology, the hydrothermal liquefaction technology can directly treat wet sludge, thereby avoiding a drying link with high energy consumption and fixing more than 80 wt% of heavy metals in the sludge to a solid-phase product. However, the traditional hydrothermal liquefaction technology has the following defects:

1) the traditional hydrothermal liquefaction technology belongs to subcritical hydrothermal liquefaction reaction, the reaction temperature is 250-350 ℃, the reaction temperature is lower than the critical temperature (374 ℃) of water, the reaction time is usually more than 20min, the preheating time is longer, secondary reaction can occur in the slow heating process, the oil yield of the traditional hydrothermal liquefaction technology is lower, meanwhile, the reaction time is longer, the length of the traditional hydrothermal liquefaction reactor is too long, and the manufacturing cost of the reactor is increased;

2) when the biological crude oil is prepared by hydrothermal liquefaction of the sludge, more than 50% of nutrient elements such as carbon, nitrogen, phosphorus and the like and a small amount of heavy metal elements can migrate into the water phase product, the organic matter and nitrogen and phosphorus content in the water phase product are high, the water phase product cannot be directly discharged into an urban sewage treatment system, and the treatment difficulty is high;

3) after the oil phase product is obtained, due to the high oxygen content, further hydrogenation upgrading is needed, a large amount of hydrogen is consumed, and the preparation cost of the biofuel is increased;

4) the traditional hydrothermal liquefaction process is easy to block when processing high solid content raw materials, and the continuous operation is unstable.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a supercritical co-rapid hydrothermal liquefaction oil preparation system and process for sludge and microalgae based on water-phase algae cultivation, which can effectively achieve the purposes of resource utilization of sludge and reduction of environmental pollution.

The present invention achieves the above-described object by the following technical means.

A supercritical co-rapid hydrothermal liquefaction oil production system for sludge and microalgae based on water-phase algae cultivation comprises a raw material conveying unit, a preheating reaction unit, a cooling and depressurizing unit, a product separation unit, an oil-phase upgrading unit and a microalgae cultivation unit;

the microalgae cultivating unit is used for cultivating microalgae; the raw material conveying unit comprises a buffer tank, an iron remover, a grinding pump, a homogenizing tank and a diaphragm pump which are sequentially connected in series according to the flow direction, the microalgae and the sludge are respectively input into the buffer tank to be mixed, and the raw material conveying unit is used for inputting the mixture into the preheating reaction unit after iron removal, grinding and homogenization;

the preheating reaction unit comprises a high-frequency electromagnetic induction heater and a supercritical rapid hydrothermal liquefaction reactor, the high-frequency electromagnetic induction heater is used for preheating the mixture and conveying the mixture to the supercritical rapid hydrothermal liquefaction reactor, and the supercritical rapid hydrothermal liquefaction reactor outputs a hydrothermal product through a supercritical co-rapid hydrothermal liquefaction reaction;

the temperature and pressure reduction unit is used for reducing the temperature and the pressure of the hydrothermal product; the product separation unit converts a hydrothermal product into a water phase product, a solid phase product and an oil phase product through centrifugal separation; the oil phase product is converted into the biofuel oil through hydrogenation upgrading by the oil phase upgrading unit.

Further, the aqueous phase product is input into a homogenizing tank for diluting the mixture; the water phase product is input into an oil phase upgrading unit and is used for providing a hydrogen source for the oil phase product; the water phase product is input into the microalgae cultivation unit and is used for providing a nutrient source required by cultivating microalgae.

Further, the temperature reduction and pressure reduction unit comprises an organic working medium Rankine cycle device and a pressure reduction device, wherein the organic working medium Rankine cycle device is used for reducing the temperature of the hydrothermal product and converting the heat energy of the hydrothermal product into electric energy; the pressure reduction device is used for reducing the pressure of the hydrothermal product.

Further, when the solid content of the mixture of the sludge and the microalgae at the outlet of the buffer tank is less than 5 wt%, the pressure reduction device is a back pressure valve; when the solid content of the mixture of the sludge and the microalgae at the outlet of the buffer tank is more than or equal to 5 wt%, the pressure reduction device is a capillary pressure reduction device.

Further, the microalgae cultivating unit comprises a photobioreactor, a collector and a drying device, and the inoculated microalgae seeds enter the photobioreactor and are used for cultivating microalgae; transporting the microalgae into a buffer pool through a collector and a drying device; the aqueous phase product is input into the bioreactor and used for providing a nutrient source required for cultivating microalgae, and the microalgae can be used for adsorbing heavy metal ions in the aqueous phase product.

An oil preparation process of a supercritical co-rapid hydrothermal liquefaction oil preparation system for sludge and microalgae based on water-phase algae cultivation comprises the following steps:

culturing microalgae through the microalgae culturing unit, respectively inputting the microalgae and sludge into a buffer pool for mixing, sequentially inputting the mixture into an iron remover, a grinding pump, a homogenizing tank and a diaphragm pump, and removing ferromagnetic impurities in the mixture through the iron remover; chopping large insoluble solids in the mixture by a grinding pump; diluting the mixture through a homogenization tank for reducing the viscosity of the mixture; inputting the mixture into the inlet end of the preheating reaction unit through a diaphragm pump;

the sludge and microalgae mixture at the outlet of the raw material conveying unit is input into a high-frequency electromagnetic induction heater, the mixture is preheated by the high-frequency electromagnetic induction heater to a temperature above the critical temperature of water, and the preheated mixture enters a supercritical rapid hydrothermal liquefaction reactor and outputs a hydrothermal product through a supercritical co-rapid hydrothermal liquefaction reaction;

cooling the hydrothermal product after passing through an organic working medium Rankine cycle device; the cooled hydrothermal product is depressurized by a depressurization device;

the decompressed hydrothermal product is converted into a water phase product, a solid phase product and an oil phase product through centrifugal separation, wherein the solid phase product can fix heavy metals; the water phase product provides a nutrient source required by growth for the microalgae in the photobioreactor, heavy metal ions in the water phase product are adsorbed by the microalgae, and the chemical oxygen demand, total nitrogen and total phosphorus content of the water phase product are reduced;

the oil phase product is subjected to hydrogenation upgrading to obtain the biofuel, and the water phase product can provide hydrogen elements required by the hydrogenation upgrading.

Further, the reaction temperature of the supercritical rapid hydrothermal liquefaction reactor is 400-600 ℃, and the reaction time is less than 5 min.

Further, the particle size of insoluble solid particles in the mixture output by the grinding pump is less than 50 μm.

Further, the temperature rise rate of the high-frequency electromagnetic induction heater is more than 100 ℃ min^-1。

Further, the organic working medium Rankine cycle device generates electric energy by cooling the hydrothermal product, and the electric energy is provided for the high-frequency electromagnetic induction heater.

The invention has the beneficial effects that:

1. according to the supercritical co-rapid hydrothermal liquefaction oil preparation system and process based on the water-phase algae culture sludge and microalgae, iron removal, grinding and homogenization are carried out on the sludge and microalgae mixed raw materials, and then the sludge and microalgae mixed raw materials are transported, so that the reliability of raw material transportation is improved. The iron removal and grinding process can ensure that no large-particle insoluble solid exists in the raw material transportation process; the viscosity of the raw materials can be reduced in the homogenizing process, meanwhile, the aqueous phase product after supercritical rapid hydrothermal liquefaction is adopted in the homogenizing process, on one hand, the consumption of system process water is reduced, on the other hand, the H/C atomic ratio of the bio-oil can be increased due to the fact that the hydrogen content of the aqueous phase product is high, and the quality of the oil phase product is improved.

2. The supercritical co-rapid hydrothermal liquefaction oil production system and process for the sludge and the microalgae based on the water-phase algae cultivation adopt the rapid hydrothermal liquefaction technology, the reaction temperature is 400-; in addition, the reaction temperature is set to be 400-400 ℃, so that the situation that the water is in a large specific volume change area of 300-400 ℃ can be avoided, the density fluctuation of the high-water-content materials such as sludge and microalgae is small at the supercritical hydrothermal liquefaction temperature (400-600 ℃), and the stability of an oil production system can be obviously improved.

3. According to the supercritical co-rapid hydrothermal liquefaction oil production system and process based on the water-phase algae culture sludge and microalgae, the high-frequency electromagnetic induction heater is adopted to replace the traditional electric heating, so that the heating rate of the sludge and the microalgae can be obviously improved, the raw materials are rapidly heated and subjected to wall breaking hydrolysis, the occurrence of unfavorable secondary reaction in the slow heating process is inhibited, and the yield of the biological crude oil is improved; meanwhile, the heat efficiency of the high-frequency electromagnetic induction heater is higher than that of a resistance heating mode, and the high-frequency electromagnetic induction heater has a power-saving effect.

4. According to the supercritical co-rapid hydrothermal liquefaction oil preparation system and process based on the sludge and the microalgae cultured by the water-phase product, the microalgae cultured by the water-phase product can not only consume nutrient substances in the water-phase product and adsorb heavy metal ions in the water-phase product, so that the problem of harmless treatment of the water-phase product is solved, but also the external source (carbon source, nitrogen source, phosphorus source and the like) nutrition cost in the microalgae culturing process can be reduced, and the cultured microalgae can be further used for supercritical rapid hydrothermal liquefaction oil preparation. Meanwhile, the sludge and the microalgae belong to high-protein biomass, and a synergistic effect can be generated in the supercritical co-hydrothermal liquefaction process, so that the oil yield can be further improved.

5. According to the supercritical co-rapid hydrothermal liquefaction oil production system and process based on the sludge and microalgae cultured by the water phase, the organic working medium Rankine cycle device is adopted to recover the heat of the product, and the generated electricity can be used for supplying power to the high-frequency electromagnetic induction heater, so that the system efficiency is improved.

6. The sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system and process based on water-phase algae cultivation adopt a back pressure valve or a capillary pressure reduction device, wherein the back pressure valve can be used for reducing the pressure of low-concentration microalgae and sludge mixtures (the solid content is less than 5 wt%), the capillary can be used for reducing the pressure of high-concentration microalgae and sludge mixtures (the solid content is more than or equal to 5 wt%), and the capillary pressure reduction can avoid the local pressure reduction of the back pressure valve and slowly reduce the pressure through the on-way resistance of the capillary.

7. According to the supercritical co-rapid hydrothermal liquefaction oil production system and process based on the sludge and microalgae cultured in the water phase, the water phase product is added in the hydrogenation upgrading stage, and the water phase product is rich in hydrogen resources and can be used as a hydrogen donor in the upgrading stage to reduce H₂Consumption.

8. According to the supercritical co-rapid hydrothermal liquefaction oil preparation system and process based on the sludge and microalgae cultured by the water phase algae, more than 80% of heavy metal elements in the raw materials can be fixed by the solid phase product, and the heavy metals in the water phase product can be further fixed in the microalgae culturing process, so that the stabilization of the heavy metals is realized.

Drawings

FIG. 1 is a process flow diagram of a supercritical co-rapid hydrothermal liquefaction oil production system for sludge and microalgae based on aqueous algae cultivation.

In the figure:

1-a buffer pool; 2-a de-ironing separator; 3-a grinding pump; 4-homogenizing tank; 5-a diaphragm pump; 6-high frequency electromagnetic induction heater; 7-supercritical rapid hydrothermal liquefaction reactor; 8-an organic working medium Rankine cycle device; 9-a pressure reduction device; 10-centrifugal separation; 11-aqueous phase product; 12-solid phase product; 13-oil phase product; 14-hydrogenation upgrading; 15-inoculation; 16-a photobioreactor; 17-a collector; and 18-a drying device.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.

As shown in fig. 1, the supercritical co-rapid hydrothermal liquefaction oil production system based on sludge and microalgae cultured in an aqueous phase comprises a raw material conveying unit, a preheating reaction unit, a temperature and pressure reduction unit, a product separation unit, an oil phase upgrading unit and a microalgae cultivation unit;

the microalgae cultivating unit is used for cultivating microalgae; the microalgae cultivating unit comprises a photobioreactor 16, a collector 17 and a drying device 18, and algae seeds are inoculated 15 and then enter the photobioreactor 16 for cultivating microalgae; the microalgae are transported into the buffer tank 1 through a collector 17 and a drying device 18;

the raw materials transport the unit and include buffer pool 1, de-ironing separator 2, grinding pump 3, homogeneity jar 4 and diaphragm pump 5 according to the flow direction series connection in proper order, little algae and mud are inputed buffer pool 1 respectively and are mixed, and 2 entrances of 1 exit linkage de-ironing separator in buffer pool set up anchor agitator in the buffer pool, and 3 entrances of 2 exit linkage grinding pumps of de-ironing separator, 3 exit linkage homogeneity jar 4 entrances of grinding pump set up oar formula or screw agitator in the homogeneity jar 4, strengthen the homogeneity effect. The raw material conveying unit is used for conveying the mixture into the preheating reaction unit through a diaphragm pump 5 after iron removal, grinding and homogenization;

the preheating reaction unit comprises a high-frequency electromagnetic induction heater 6 and a supercritical rapid hydrothermal liquefaction reactor 7, the high-frequency electromagnetic induction heater 6 is used for preheating the mixture to a temperature above the approach temperature of water and conveying the mixture to the supercritical rapid hydrothermal liquefaction reactor 7, and the supercritical rapid hydrothermal liquefaction reactor 7 outputs a hydrothermal product through a supercritical co-rapid hydrothermal liquefaction reaction; the supercritical rapid hydrothermal liquefaction reactor 7 can be a serpentine tube reactor, a coil tube reactor, a tower reactor or a continuous kettle reactor;

the temperature and pressure reduction unit is used for reducing the temperature and the pressure of the hydrothermal product; the temperature reduction and pressure reduction unit comprises an organic working medium Rankine cycle device 8 and a pressure reduction device 9, the organic working medium Rankine cycle device 8 converts the heat energy of the hydrothermal product into electric energy, and meanwhile, the temperature of the hydrothermal product is reduced; the electric energy generated by the organic working medium Rankine cycle device 8 can be input into the high-frequency electromagnetic induction heater 6. The pressure reduction device 9 is used for reducing the pressure of the hydrothermal product. When the solid content of the mixture of the sludge and the microalgae at the outlet of the buffer tank 1 is less than 5 wt%, the pressure reduction device 9 is a back pressure valve; when the solid content of the mixture of the sludge and the microalgae at the outlet of the buffer tank 1 is more than or equal to 5 wt%, the pressure reduction device 9 is a capillary pressure reduction device.

The temperature and pressure reduction unit is communicated with the product separation unit, and the product separation unit converts the hydrothermal product into a water phase product 11, a solid phase product 12 and an oil phase product 13 through centrifugal separation 10;

the oil phase product 13 is converted to biofuel by the oil phase upgrading unit. Specifically, the oil phase product 13 can be hydrogenated to improve quality and reduce the oxygen content by 14 to obtain the biofuel oil which can be used in the transportation industry.

In fig. 1, it can be seen that the aqueous phase product 11 can enter the photobioreactor 16 in the microalgae cultivation unit, provide carbon, nitrogen and phosphorus elements required for microalgae growth, reduce the chemical oxygen demand, total nitrogen and total phosphorus content of the aqueous phase product 11, and the microalgae can adsorb heavy metal ions in the aqueous phase product 11; the aqueous phase product 11 can also enter the homogenizing tank 4, and the viscosity is reduced under the stirring and the dilution of the aqueous phase product 11; the water phase product 11 can also enter a hydrogenation upgrading 14 process to provide a hydrogen source for the oil phase product 13, so that the consumption of hydrogen in the hydrogenation upgrading 14 process is reduced.

Example 1

As shown in fig. 1, the oil production process of the water-phase algae-culturing-based sludge and microalgae supercritical co-rapid hydrothermal liquefaction oil production system comprises the following steps:

conveying raw materials: conveying sludge generated by a sewage treatment plant to an inlet end of a buffer tank 1, conveying cultivated microalgae to an inlet end of the buffer tank 1, mixing the sludge and the microalgae in the buffer tank 1, wherein the water content of the sludge and the microalgae is 70-95 wt%, the viscosity of the sludge and the microalgae is 1000-200000mPa & s, and primarily mixing the sludge and the microalgae by using an anchor stirrer in the buffer tank 1; the sludge and the microalgae after the preliminary mixing enter the inlet end of the iron remover 2 to remove ferromagnetic impurities in the raw materials, so that the safe operation of the grinding pump 3 is ensured; conveying the raw materials subjected to iron removal to the inlet end of the grinding pump 3, chopping large-particle insoluble solids in the sludge and microalgae, and ensuring that the particle size of insoluble particles at the outlet end of the grinding pump 3 is less than 50 mu m to prevent the subsequent pipeline from being blocked; the sludge and the microalgae are ground and then conveyed to a homogenizing tank 4, if the water content of the mixture of the sludge and the microalgae is lower than 87 wt%, the raw materials are diluted by a water phase product 11, the problem of blockage in the conveying process of high-concentration materials is avoided, the consumption of process water is reduced, meanwhile, the water phase product 11 is rich in hydrogen sources, the H/C atomic ratio of an oil phase product 13 can be improved, and the viscosity of the raw materials is reduced to be less than 8000mPa & s under the action of a paddle type or screw type stirrer in the homogenizing tank 4; the homogenized sludge and microalgae are continuously conveyed into a preheating reaction unit through a diaphragm pump 5;

preheating reaction: the sludge and the microalgae are quickly preheated to 400-500 ℃ by a high-frequency electromagnetic induction heater 6 and then enter a supercritical quick hydrothermal liquefaction reactor 7 to carry out a supercritical common quick hydrothermal liquefaction reaction; the temperature rise rate of the high-frequency electromagnetic induction heater 6 is more than 100 ℃ min^-1The sludge and the microalgae flocs are rapidly dispersed, microbial cells are rapidly broken, the raw materials are rapidly hydrolyzed, the occurrence of unfavorable secondary reaction in the slow temperature rise process is inhibited, and the yield of the biological crude oil is improved; in the supercritical rapid hydrothermal liquefaction reactor 7, when the reaction temperature is 400 ℃, the reaction time is less than 4min or the reaction temperature is 450 ℃, the reaction time is less than 3min, the yield of the oil phase product 13 higher than 25 wt% can be obtained, and the problem of raw material density fluctuation easily generated in the subcritical hydrothermal liquefaction process is avoided; in addition, the sludge and the microalgae belong to high-protein biomass, and a synergistic effect can be generated in the supercritical co-hydrothermal liquefaction process, so that the oil yield can be further improved;

cooling and reducing pressure: the temperature of the reaction product is reduced to 30-90 ℃ through the organic working medium Rankine cycle device 8, the organic working medium Rankine cycle device 8 provides electric energy for the high-frequency electromagnetic induction heater 6, the reaction temperature is rapidly increased, and meanwhile the system efficiency is improved; the reaction product after being cooled is depressurized to normal pressure by a pressure reducing device 9 and then is conveyed to a product separation unit, the pressure reducing device 9 adopts a backpressure valve or a capillary, wherein the low-concentration mixed material with the solid content of less than 5 wt% is depressurized by the backpressure valve, the high-concentration mixed material with the solid content of more than or equal to 5 wt% is depressurized by the capillary, the capillary is depressurized to avoid the local pressure drop of the backpressure valve, and the stable depressurization is realized by the on-way resistance of the capillary;

and (3) product separation: due to the density difference of different products, the reaction product after temperature reduction and pressure reduction is centrifugally separated 10 into an upper oil phase product 13, a middle water phase product 11 and a lower solid phase product 12, wherein more than 80 wt% of heavy metals in the sludge and microalgae can be fixed to the solid phase product 12;

culturing microalgae: the water phase product 11 enters a photo-bioreactor 16 in the microalgae cultivation unit, necessary elements such as carbon, nitrogen, phosphorus and the like for the growth of microalgae are provided, and the chemical oxygen demand, total nitrogen and total phosphorus content of the water phase product 11 are reduced, wherein the chemical oxygen demand, total nitrogen and total phosphorus removal rates of the water phase product 11 in the growth process of microalgae are respectively higher than 50%, 60% and 80%, the microalgae can adsorb heavy metal ions in the water phase product 11, and the problem of harmless treatment of the water phase product 11 after hydrothermal liquefaction is solved; the cultivated microalgae enter a raw material conveying unit.

Oil phase upgrading: the oil phase product 13 is hydrogenated and upgraded 14 to obtain the biofuel oil H₂Or the water phase product 11 after the supercritical co-rapid hydrothermal liquefaction of the sludge and the microalgae can be used as a hydrogen source, wherein the water phase product 11 is rich in the hydrogen source and can be used as a hydrogen donor in an upgrading stage to reduce H₂Consumption.

Example 2

Example 2 differs from example 1 in that: the sludge and the microalgae are quickly preheated to 600 ℃ by a high-frequency electromagnetic induction heater 6 and then enter a supercritical quick hydrothermal liquefaction reactor 7 to carry out supercritical co-quick hydrothermal liquefaction reaction, and when the reaction temperature is 500 ℃, the reaction time is less than 1min or the reaction temperature is 550 ℃, the reaction time is less than 50s or the reaction temperature is 600 ℃, and the reaction time is less than 40s, the yield of the oil phase product 13 higher than 25 wt% can be obtained.

It should be understood that although the present description has been described in terms of various embodiments, not every embodiment includes only a single embodiment, and such description is for clarity purposes only, and those skilled in the art will recognize that the embodiments described herein may be combined as suitable to form other embodiments, as will be appreciated by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.