1962 results about "Supercritical carbon dioxide" patented technology

The invention discloses a supercritical carbon dioxide energy storage system and method based on porous liquid absorption and storage, and belongs to the technical field of energy storage industry. Comprising a low-pressure storage system for storing low-pressure carbon dioxide; the compression energy storage system is used for compressing the carbon dioxide energy storage working medium; the high-pressure storage system is used for obtaining and storing high-pressure supercritical carbon dioxide; the expansion energy release system is used for high-pressure supercritical expansion energy release and pushing a power generator to generate power; and the heat circulation system exchanges heat with and circulates heat with the compression energy storage system and the expansion energy release system. A porous liquid absorbent is adopted. Permanent gaps for containing carbon dioxide can be provided, the problem of a carbon dioxide low-pressure storage end can be solved, and the system investment cost is greatly reduced. High-density storage of the low-voltage end of carbon dioxide is achieved through a chemical absorption method, the supercritical carbon dioxide compression energy storage system stores excess electric quantity generated by the renewable energy system, expansion power generation is carried out in the power utilization peak, and the peak regulation capacity of a power grid is improved.

The invention provides a supercritical CO2 fracturing, displacement and storage integrated experimental device and method, belongs to the technical field of natural gas development, and is used for solving the problem that a real-time and multidirectional monitoring and evaluation experimental device for simulating a deep unconventional natural gas exploitation process is lacked. The supercritical CO2 fracturing, displacement and sealing integrated experimental device comprises an accommodating cavity, a ground stress simulation system, a gas source supply system, a fracturing fluid preparation system, a temperature control system, a tail gas recovery system, a multi-parameter monitoring system and a displacement effect evaluation system, and can systematically simulate true triaxial ground stress and ground temperature conditions; fracturing, displacement and sequestration experiments of supercritical carbon dioxide on a rock sample are carried out, multi-azimuth and multi-parameter real-time monitoring and quantitative characterization evaluation are carried out on experimental results in the experimental process, and important theoretical research and actual production guiding significance is achieved for development of deep unconventional natural gas and geological sequestration of carbon dioxide.

The invention discloses a thin mutual coal seam fracturing, gasification and carbon sequestration integrated method. The method comprises the steps of geological exploration and coal seam refined evaluation; a middle horizontal well is drilled downwards from the ground; top and bottom horizontal wells are planned and drilled in the uppermost and lower sandstone stratums of the thin mutual coal seam; a plurality of top and bottom fishbone wells are drilled obliquely downwards and upwards in the top and bottom horizontal wells; oxygen-enriched water vapor is injected into the middle horizontal well through a continuous oil pipe, the oxygen-enriched water vapor is squeezed into the reservoir under the action of high pressure, and fracturing operation is conducted; initiating an underground gasification process of the coal seam, and synchronously performing extraction operation of the coal seam gas; supercritical CO2 fracturing operation is conducted on the top horizontal well and the bottom horizontal well; injecting water-based fracturing fluid into the top horizontal well and the bottom horizontal well; gasified materials generated by coal seam combustion gasification and desorbed methane gas are extracted through the middle horizontal well, and supercritical carbon dioxide injected before is sealed for a long time. According to the method, the limitation of a traditional hydraulic fracturing technology can be solved, and the transformation effect of the reservoir can be improved.

The invention relates to the technical field of supercritical compressed carbon dioxide energy storage, in particular to an adiabatic supercritical compressed carbon dioxide energy storage system. An expansion unit; during energy storage, the heat storage tank stores compression heat of the supercritical carbon dioxide in the high-temperature and high-pressure state, and the supercritical carbon dioxide in the high-temperature and high-pressure state is cooled to the temperature the same as that of the high-pressure gas storage chamber; during energy release, the heat storage tank heats the low-temperature high-pressure supercritical carbon dioxide discharged from the high-pressure gas storage chamber; the temperature control system adjusts the flow of the cooling medium in the second heat exchanger, controls the inlet temperature of the compressor and further adjusts the inlet temperature of each stage of expansion machine, it is guaranteed that the carbon dioxide temperature of the inlet position of each stage of expansion machine is not lower than the liquefaction critical temperature, and the large-area liquefaction phenomenon does not occur. According to the temperature control system, the phenomenon that in the prior art, when carbon dioxide is at low temperature, carbon dioxide is liquefied, and large-area condensation occurs in the expansion machine can be effectively overcome, and then the operation efficiency and the energy storage efficiency of the system are guaranteed.

The invention discloses a supercritical carbon dioxide mineralization and storage method based on a paste filling technology. The supercritical carbon dioxide mineralization and storage method comprises the following steps: S1, preparing a paste filling material; s2, preparing supercritical carbon dioxide; s3, mineralization and storage: in order to realize large-scale mineralization and storage of CO2 in the mine, the mineralization and storage step comprises a mineralization filling slurry preparation process and a carbon injection mineralization process; according to the supercritical carbon dioxide mineralization and storage method based on the paste filling technology, the paste filling technology and supercritical carbon dioxide mineralization and storage are combined, mine solid waste with a large number of calcium and magnesium resources and supercritical carbon dioxide are fully mineralized, mineralization filling slurry is prepared and filled into an underground goaf, and the mining goaf is filled with the mineralization filling slurry. The mechanical property and the pore structure of the filling body are improved, the concept of treating waste with waste in a mine is met, and green mining of the metal mine is achieved.

The invention relates to the technical field of aircrafts, in particular to a built-in compressed air and carbon dioxide linkage drainage system and an aircraft. The drainage system comprises a drainage device, a water ballast tank, a first connecting pipeline and a control unit, a first storage cavity for storing liquid carbon dioxide is formed in the first power unit, a second storage cavity for storing high-pressure air is formed in the second power unit, and a pressure reduction cavity is formed in the pressure reduction unit; the first storage chamber and the second storage chamber are both selectively communicated with the pressure reduction chamber; the water ballast tank is provided with a third storage chamber selectively communicated with the pressure reduction chamber; the first connecting pipeline is connected with the second power unit and the pressure reduction unit, and a first on-off valve is arranged on the first connecting pipeline; the first power unit is suitable for converting liquid carbon dioxide into high-pressure supercritical carbon dioxide under the control of the control unit, and the high-pressure supercritical carbon dioxide enters the third storage chamber after being decompressed by the decompression chamber, so that the first connecting pipeline selectively communicates with the second storage chamber and the decompression chamber.

The invention relates to the technical field of underwater vehicles, in particular to a modular supercritical carbon dioxide phase change drainage device and an underwater vehicle. The modular supercritical carbon dioxide phase change drainage device comprises a plurality of power unit sets, a plurality of pressure reduction units and a flow guide assembly, each power unit set comprises a plurality of power units, each power unit is provided with a first storage cavity, and the first storage cavity is used for storing liquid carbon dioxide; the plurality of pressure reduction units are in one-to-one correspondence with the plurality of power unit groups, each pressure reduction unit is provided with a pressure reduction chamber, the pressure reduction chambers selectively communicate with the corresponding first storage chambers, and the pressure reduction chambers of the plurality of pressure reduction units communicate with one another; the flow guide assembly is provided with a first air inlet and a first air outlet, the first air inlet communicates with at least one of the multiple pressure reduction cavities, and the first air outlet communicates with the water ballast space. The modular supercritical carbon dioxide phase change drainage device is small in occupied space, safe, efficient and high in drainage capacity.

The invention provides a shale supercritical carbon dioxide and carbon dioxide storage coupling simulation method. The method comprises the following steps: acquiring simulation information of a target research area; on the basis of the simulation information, physical scenes and chemical reaction scenes related to recovery ratio improvement of SCCO2-CO2 displacement shale gas and CO2 sequestration are simulated, and a physical simulation result and a chemical simulation result are obtained; performing data exchange on the physical simulation result and the chemical simulation result at the same time step length under the coupling effect; updating parameter information corresponding to physical scene simulation of the next time step based on a data exchange result, and returning to re-simulation until numerical simulation of a specified number of time steps is completed; after numerical simulation of the specified number of time steps is completed, a target simulation result is obtained; and calculating a carbon dioxide sequestration value based on the target simulation result. According to the method, the SCCO2-CO2 displacement shale gas can be finely and comprehensively described under the multi-dimensional condition, and the recovery efficiency and the subsequent CO2 storage process are improved.

The invention provides a coal rock microcosmic fracture dynamic corrosion seepage analysis method and device. The method comprises the steps that initial microcosmic fracture structure image information of coal rock in an initial state and real-time microcosmic fracture structure image information of the coal rock in a supercritical carbon dioxide injection state are obtained; preprocessing the initial microcosmic fracture structure image information and the real-time microcosmic fracture structure image information to obtain initial fracture geometrical morphology information and real-time fracture geometrical morphology information; according to the initial fracture geometrical morphology information and the real-time fracture geometrical morphology information, initial equivalent permeability and real-time equivalent permeability are obtained; and obtaining a target analysis result according to the initial equivalent permeability and the real-time equivalent permeability. According to the scheme, the phase change process of supercritical carbon dioxide, the evolution of a coal body microscopic fracture structure and the microscopic distribution of fluid can be displayed; the dynamic corrosion effect of the supercritical carbon dioxide on the coal fracture structure and the permeability evolution rule are disclosed.

The invention discloses a control method and device for a supercritical carbon dioxide recompression cycle power generation system, and the method comprises the steps: predicting the load change of the supercritical carbon dioxide Brayton cycle power generation system according to the historical operation data and current operation state of the supercritical carbon dioxide Brayton cycle power generation system; predicting the surge risk of the compressor according to the load change of the supercritical carbon dioxide Brayton cycle power generation system; according to the load change of the supercritical carbon dioxide Brayton cycle power generation system, the split ratio is adjusted, so that the recompression Brayton cycle power generation system operates at the optimal efficiency; and the flow, pressure and temperature of a compressor working medium in the supercritical carbon dioxide Brayton cycle power generation system are adjusted according to the surge risk, so that the compressor works in a non-surge area. When the supercritical carbon dioxide Brayton cycle power generation system approaches the surge boundary, the system adjusts the opening degree of the bypass valve in advance for flow release, so that active closed-loop control of surge prediction-response-relief is achieved, a compressor is effectively prevented from entering an unstable area under sudden load change, start and stop or extreme disturbance, and the service life of the compressor is prolonged. And the safety stability and the operation continuity of the system are obviously improved.

The invention discloses a green processing technology of sea cucumber powder capable of realizing directional enrichment and improving polysaccharide release rate, and belongs to the field of food processing. The sea cucumber powder is prepared by the following steps: S1, pretreating sea cucumbers; s2, enrichment of nutrient substances of the sea cucumbers; s3, regulating and controlling the particle size of the sea cucumber powder; s4, performing'single 'supercritical treatment; s5, carrying out in-situ ultramicro physical crushing; and S6, performing'dual 'supercritical treatment. Through the design of the gas disperser and the additional arrangement of the second hole disc, the supercritical extraction instrument can perform effective supercritical carbon dioxide extraction on the ultramicro sea cucumber powder, the deodorization of the ultramicro sea cucumber powder is realized, and the eating quality of the ultramicro sea cucumber powder is improved. Moreover, by detecting and regulating the stacking density and the tap density, optimal processing parameters for the ultramicro sea cucumber powder are found, so that the prepared ultramicro sea cucumber powder is high in polysaccharide release rate, good in eating quality and easy for subsequent processing.

The invention relates to a preparation method of silica gel microspheres used as a catalyst carrier, which comprises the following steps of: adjusting the speed of converting acidified water glass into gel by means of controlling material temperature and material concentration, multiple times of acidification and the like, so that the acidified water glass is atomized to form liquid drops, and then the liquid drops are quickly converted into the gel; and carrying out aging, acid washing, water washing, supercritical carbon dioxide drying, roasting in an atmosphere furnace and the like to prepare the silica gel microspheres with high specific surface area and large pore volume. Compared with the prior art, the specific surface area of the obtained silica gel can reach 250-450 m < 2 > / g, the pore volume can reach 1.5-3.0 cm < 3 > / g, and the silica gel has good strength and fluidity.

The invention relates to the technical field of CO2 miscible-phase oil displacement, in particular to an ester gas-soluble surfactant for reducing CO2 miscible-phase pressure and a preparation method and application thereof.The ester gas-soluble surfactant is prepared from polyglycerol fatty acid ester and acetic anhydride, the ester gas-soluble surfactant contains unsaturated hydrocarbon chains with the carbon atom number being 8-18, and the unsaturated hydrocarbon chains are connected with the polyglycerol fatty acid ester. N is the polymerization degree of the polyglycerol fatty acid ester, n is any integer in the range of 2-22, and the ester gas-soluble surfactant has the solubility of 0.5 wt%-1.5 wt% in supercritical carbon dioxide. When the ester gas-soluble surfactant provided by the invention is used, other auxiliaries do not need to be added, and a good mixing reduction effect can be achieved aiming at different crude oils by adjusting the number of carbon dioxide-philic groups and the length of oleophylic unsaturated hydrocarbon chains.

The invention relates to the technical field of nuclear facility decontamination, and provides a multiphase carbon dioxide decontamination recovery system and a decontamination recovery process, the decontamination recovery system comprises a dry ice supply loop, a high pressure CO2 supply loop, a decontamination loop and a CO2 recovery loop; the tail ends of the dry ice supply loop and the high-pressure CO2 supply loop are communicated with the decontamination loop; the tail end of the decontamination loop is communicated with the CO2 recovery loop; the decontamination recovery process comprises the following steps: taking ethanol or acetone as an entrainer, dissolving a decontaminating agent by using supercritical carbon dioxide to carry out soaking decontamination pretreatment on the radioactive contamination surface, taking high-pressure carbon dioxide as power, carrying dry ice particles and spraying out from a high-pressure spraying pipe to impact the radioactive contamination surface, and recycling the radioactive contamination surface. Recycling of carbon dioxide is realized through two-stage depressurization separation and first-stage filtration; the carbon dioxide radioactive decontamination capability and efficiency can be remarkably improved, the secondary waste generation amount is reduced, and the personnel irradiation risk is reduced.

The invention relates to the technical field of thermal hydraulic power, in particular to a rapid prediction method for flow heat transfer characteristics of supercritical carbon dioxide of a micro-channel heat exchanger, and the method comprises the steps: dividing a training set and a test set according to a preset working condition parameter space, and generating a full-order flow field database under multiple working conditions through numerical simulation; performing eigenorthogonal decomposition on the full-order flow field database, and extracting a key mode of a dominant flow heat transfer feature to construct a reduced-order solution space; training an optimized neural network model by using the training set, and establishing a mapping relationship between the working condition parameters and the reduced-order solution space; and reconstructing flow field and temperature field information based on the mapping relation, and calculating and outputting a flow heat transfer characteristic prediction result. The method aims at solving the technical problem that the heat transfer characteristic prediction calculation efficiency of the supercritical carbon dioxide heat transfer flow of the micro-channel heat exchanger is low.

The invention belongs to the technical field of monitoring equipment, and discloses a supercritical carbon dioxide contact angle direct monitoring system and method.A first needle valve is connected with the bottom of a high-temperature and high-pressure reaction kettle, the other side of the first needle valve is connected with a supercritical carbon dioxide storage device, and a heater is arranged on the periphery of the columnar high-temperature and high-pressure reaction kettle; a sight glass is arranged on the side face of the high-temperature and high-pressure reaction kettle, a light source is arranged on the left side of the high-temperature and high-pressure reaction kettle, the top of the high-temperature and high-pressure reaction kettle is connected with a second needle valve, the other side of the second needle valve is connected with a water injection pump, and a CCD camera is arranged on the right side of the high-temperature and high-pressure reaction kettle and connected with a computer. The computer is connected with the high-temperature and high-pressure reaction kettle through the temperature sensor and the pressure sensor. According to the invention, the change of the contact angle of the supercritical carbon dioxide can be accurately monitored and analyzed in real time, and an effective tool is provided for researching the wettability of the supercritical carbon dioxide and the effects of anisotropy, cohesiveness, adsorptivity and the like of the surface of a material.

The invention discloses a purification method for removing quartz inclusion, which comprises the following steps: calcining a quartz sand raw material at high temperature for a certain time, then taking out and quickly putting into cold water for cold quenching; dehydrating quartz sand, feeding into a microwave reactor, heating to a set temperature, and keeping for a period of time; after the reaction is finished, cleaning the quartz sand with ultrapure water; filling the quartz sand into a high-temperature and high-pressure reactor, introducing supercritical carbon dioxide and hydrogen fluoride mixed gas, and keeping the temperature and the pressure for a period of time; and after the reaction is finished, discharging gas to obtain the high-purity quartz. Through two-stage heat treatment, a channel between gas-liquid inclusions in quartz particles and the outside can be efficiently opened, and meanwhile, the supercritical method ensures that impurities in the inclusions can be effectively dissolved out; the treatment time is short, the required temperature is low, the acid consumption is less than 10%, and the method has the advantages of high efficiency and low cost.

The invention discloses supercritical fluid foaming polyimide wave-absorbing foam and a preparation method thereof.The thermoplastic polyimide is prepared by the steps that aromatic dianhydride, aromatic diamine and aliphatic diamine serve as comonomers, polyimide acid is generated through solution polymerization, and then high-temperature cyclization is conducted; wherein the mole number of the aliphatic diamine accounts for 10-50% of the total mole number of the diamine, and the free volume and glass transition temperature of a molecular chain are effectively regulated and controlled by introduction of the aliphatic diamine; the wave-absorbing foam is prepared by taking polyimide as a matrix, doping 1-20wt% of wave-absorbing filler, and foaming for 1-3 hours in a supercritical carbon dioxide or nitrogen environment at the temperature of 180-220 DEG C and the pressure of 9-25MPa, through molecular structure design, the adsorption capacity and impact resistance of polyimide to carbon dioxide are remarkably improved, and the prepared foam has the advantages of light weight, high porosity, uniform foam structure and excellent heat resistance, can realize effective electromagnetic wave absorption in an X wave band, and is suitable for the fields of aerospace stealth and electromagnetic compatibility protection.

The invention discloses a technology for manufacturing a thin film by recycling and calendering a polytetrafluoroethylene material, and belongs to the technical field of high polymer material recycling and processing, the technology for manufacturing the thin film by recycling and calendering the polytetrafluoroethylene material comprises the following steps: crushing waste products, and carrying out three-stage screening impurity removal and melt index detection; after being cleaned by supercritical carbon dioxide, the qualified material is mixed with industrial by-product filler, waste tire rubber powder and the like, low-temperature mixing is conducted through a double-screw extruder, and mixing parameters are automatically regulated and controlled through a tension sensor; performing calendaring forming by a five-roller calendaring unit, preheating the first two rollers, performing differential stretching by the middle three rollers, engraving a micro groove by the third roller, and controlling the thickness precision to be + / -3% by an online thickness gauge; the film is slit after being compounded according to requirements, and scrap edges are crushed and recycled. The method realizes efficient recovery of waste polytetrafluoroethylene, and has the advantages of thorough impurity removal, stable performance, environmental protection and energy saving.

The invention provides a supercritical carbon dioxide core displacement experiment device and method, and the device comprises a supercritical carbon dioxide preparation system, a displacement reaction system, a temperature and pressure control system, a recovery metering system, and a data acquisition monitoring system. Flexible preparation of supercritical carbon dioxide can be achieved, the oil displacement process in the oil reservoir stratum environment can be accurately reduced, the experimental device is high in modification flexibility, and data collection, transmission and monitoring are efficient and high in precision. A series of experiment requirements of supercritical carbon dioxide preparation, injection oil displacement, data processing and the like can be conveniently met, the device can be conveniently subjected to experiment modification through the arrangement of the pipeline, the valve and the sensor, various experiment purposes are achieved, the utilization efficiency of the experiment device is improved, experiment operation is efficient, the carbon dioxide oil displacement and sealing experiment effects can be explored, and the experimental device is suitable for popularization and application. The method provides an experimental research thought for oil reservoir recovery efficiency, and has important guiding significance on improvement of oil and gas field recovery efficiency and development of a negative carbon technology.

The invention provides a biological magnesium alloy micro-arc oxidation coating supercritical hole sealing method based on a thermodynamic sedimentary phase diagram, which comprises the following steps: establishing deposition-dissolution balance of metal ion phosphide and hydroxide of a phosphate conversion film in a supercritical carbon dioxide environment at different pH values to obtain the thermodynamic sedimentary phase diagram; selecting a NaH2PO4 solution according to a thermodynamic sedimentary phase diagram, and adding NaHCO3 to obtain a hole sealing solution; the hole sealing solution is injected into a reaction kettle to be heated, and then a refrigerator is started to convert generated carbon dioxide gas into supercritical carbon dioxide; and the biological magnesium alloy subjected to micro-arc oxidation is placed in the hole sealing solution in the reaction kettle to be pressurized, and holes of the micro-arc oxidation coating on the surface of the biological magnesium alloy are sealed. The invention provides a supercritical hole sealing method for a biological magnesium alloy micro-arc oxidation coating based on a thermodynamic sedimentary phase diagram. And the hole sealing effect is good.

The invention discloses a decoupling control system and method for a supercritical carbon dioxide direct circulation nuclear power plant. A compressor inlet temperature constant control strategy and a compressor inlet pressure constant control strategy are adopted. A compressor inlet temperature control system adjusts the opening degree of a cooler cold side valve, and a compressor inlet pressure control system adjusts the working medium filling and discharging of a capacity box. In order to guarantee the power supply quality, a transmission shaft rotating speed constant control strategy is adopted, and transmission shaft auxiliary torque is adjusted through a transmission shaft rotating speed control system. In order to ensure the system efficiency, a reactor core outlet temperature constant control strategy is adopted, and a reactor core outlet temperature control system is used for adjusting the opening degree of a control valve; in order to achieve the reactor following operation target, a reactor core power matching demand power control strategy is adopted, the control rod speed is adjusted through a power control system, and based on the neuron PID decoupling control technology, the control target that each output parameter in the system is only influenced by a certain specific input parameter is achieved.

Methods and apparatus to provide vortex cooled secondary flow for a supercritical carbon dioxide pump are disclosed herein. An example thermal management system includes a hot secondary flow extract section fluidly coupled to an outlet of a pump system, a cooled secondary flow section fluidly coupled to the hot secondary flow extract section, the hot secondary flow extract section including a vortex tube to generate cooled secondary air flow from hot secondary flow extract air of the hot secondary flow extract section, and a bearing inlet fluidly coupled to the cooled secondary flow section, the bearing inlet positioned to route the cooled secondary flow to bearings of the pump system.

The invention provides a hydrogen direct-fired supercritical carbon dioxide energy storage power generation device system and an operation method. The hydrogen direct-fired supercritical carbon dioxide energy storage power generation device system comprises a hydrogen production and storage unit, a carbon dioxide energy storage unit and a hydrogen fuel combustion power generation unit. And the hydrogen production and storage unit and the carbon dioxide energy storage unit are respectively connected with the hydrogen fuel combustion power generation unit. Two energy storage media of liquid carbon dioxide and high-energy-density green hydrogen are used for energy storage, and super-long-time energy storage can be achieved; and heat energy is subjected to cascade coupling application, stored heat and turbine exhaust heat are fully used for a carbon dioxide cyclic heating heat source, the external emission heat loss of the system is reduced, and the system efficiency is high.

This invention discloses a supercritical carbon dioxide cycle generator set water spray desuperheating system, comprising a supercritical carbon dioxide cycle power generation system and a water spray desuperheating system; the supercritical carbon dioxide cycle power generation system includes a heater, a screen-type superheater, a final-stage superheater, and a turbine; the water spray desuperheating system includes a first desuperheating water injection point, a second desuperheating water injection point, and a liquid-water separation system; the heater outlet is sequentially connected to the turbine inlet via the first desuperheating water injection point, the screen-type superheater, the second desuperheating water injection point, and the final-stage superheater; the turbine outlet is connected to the inlet of the liquid-water separation system; the liquid outlet of the liquid-water separation system is connected to the first and second desuperheating water injection points; and the gas outlet of the liquid-water separation system is connected to the heater inlet. This system can solve various problems caused by carbon dioxide desuperheating.

A refrigeration cycle is connected to a supercritical carbon dioxide (sCO2) power cycle by incorporating a CO2 condenser which is also the refrigeration cycle evaporator. The heat rejected by the carbon dioxide is absorbed by the refrigerant in the CO2 condenser. Work is done on the refrigerant to raise its temperature above the local ambient temperature. The heat absorbed from the power cycle and the work required to raise the refrigerant temperature is rejected to the ambient environment, which may be either air, earth, or water. This results in improved efficiencies in carbon dioxide power cycles without regard to the ambient temperature by forcing a transcritical phase change even when ambient temperatures are above the carbon dioxide critical point. A two-phase heat transfer on both sides of the CO2 condenser further improves efficiency of the sCO2 power cycle.

The invention discloses an in-situ carbon-coated positive electrode lithium supplement agent, a preparation method and application, and belongs to the field of lithium ion batteries. The preparation method of the positive electrode lithium supplement agent comprises the following steps: S1, mixing lithium oxalate with a carbon source, and grinding to prepare mixed powder; s2, the mixed powder is placed in a reaction kettle, sealing and vacuumizing are conducted, carbon dioxide gas is introduced, and the pressure is controlled to be 10-20 Mpa; keeping the temperature at 30-60 DEG C and reacting for 10-24 hours; and S3, exhausting, washing with alcohol, centrifuging and drying to obtain the in-situ carbon-coated positive electrode lithium supplement agent. The invention provides a preparation method of an in-situ carbon-coated positive electrode lithium supplement agent, which comprises the following steps: placing lithium oxalate and a carbon source in a supercritical carbon dioxide fluid, stirring and dissolving, controlling the reaction temperature and pressure to promote the polymerization reaction of carbon source micromolecules, and depositing a layer of compact and uniform carbon material on the surface of lithium oxalate particles in situ, thereby obtaining the in-situ carbon-coated positive electrode lithium supplement agent. The conductivity and the ion mobility of the material are improved, so that the electrochemical activity of lithium oxalate is improved.

The invention belongs to the technical field of coal-fired power generation, and particularly relates to a Carnot battery system based on a coal-fired power generation unit and an operation method of the Carnot battery system. The Carnot cell system comprises a heat pump system taking supercritical carbon dioxide as a working medium, a heat storage system and a coal-fired power generation system; the heat pump system comprises a first compressor, a second compressor, a first heat regenerator, a second heat regenerator, a third heat regenerator, a first turbine and a second turbine; the heat storage system comprises a hot tank and a cold tank; the coal-fired power generation system comprises a coal-fired boiler, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a power generator, a condenser, an eighth low-pressure heater, a seventh low-pressure heater, a sixth low-pressure heater, a fifth low-pressure heater, a deaerator, a first high-pressure heater, a second high-pressure heater and a third high-pressure heater. The split-flow compression process and the split-flow expansion process are matched with the multi-stage heat regenerator and the multi-stage fused salt heater, the energy efficiency coefficient of the Carnot battery in the electricity-to-heat conversion process is improved, and therefore the round-trip efficiency of the Carnot battery is improved.

The invention discloses a supercritical carbon dioxide pipeline transportation simulation method and device. The method comprises the following steps: acquiring physical property data of the supercritical carbon dioxide pipeline; correcting the unit of the physical property data; obtaining a preset steady-state calculation formula; correcting a partial derivative formula in the preset steady-state calculation formula to obtain a corrected steady-state calculation formula; and inputting the physical property data after unit correction into the corrected steady-state calculation formula, and carrying out steady-state calculation so as to realize static simulation of supercritical carbon dioxide pipeline transportation. According to the scheme provided by the invention, by correcting the physical property unit in the steady-state calculation formula and correcting the partial derivative formula of the unit mass flow rate of the energy equation part in the steady-state calculation formula on the fixed distance, the correctness of steady-state data of supercritical carbon dioxide during pipeline transportation is ensured.

The invention relates to the technical field of underwater vehicles, and discloses a built-in phase change drainage system and an underwater vehicle, the built-in phase change drainage system comprises a drainage device, a water ballast tank and a control unit, the drainage device comprises a first power unit and a pressure reduction unit, a first storage chamber for storing liquid carbon dioxide is arranged in the first power unit, and a pressure reduction chamber is arranged in the pressure reduction unit; the water ballast tank is provided with a containing cabin used for containing water, and the containing cabin is selectively communicated with the pressure reduction cavity. The control unit is in communication connection with the first power unit, the first power unit is suitable for converting liquid carbon dioxide into high-pressure supercritical carbon dioxide under the control of the control unit, and the carbon dioxide enters the containing cabin after being subjected to pressure reduction of the pressure reduction cavity so as to discharge water in the containing cabin. The drainage system is safe, efficient and high in drainage capacity.