351 results about "Compression system" patented technology

The invention provides a water working medium quasi-saturated compression high-temperature heat pump system based on an ejector, and belongs to the field of compression heat pumps. The problems that after an existing compression system flows through a throttling valve, the superheat degree of steam exhaust is large due to high-temperature lift compression, and the loss of available energy in the throttling process from condensate to a two-phase region is too large are solved. A multi-stage spraying atomization structure is adopted, a micro-nano liquid drop mist flow with the particle size controllable to be 50-200 nm and the liquid mass fraction adjustable to be 5%-10% is formed before compression, the airflow humidity regulation and control precision is remarkably improved, the quasi-saturation compression process is matched, and the thermal matching performance and the energy efficiency level of a system are effectively improved; a main flow inlet of the jet atomizer is changed into a compressor outlet from a condenser outlet, so that the response speed is increased, and meanwhile the jet atomizer is suitable for a complex variable-working-condition system; or single-stage compression is optimized into a two-stage compression form, so that higher heating temperature and more stable system operation are realized; or liquid from a lower-pressure position is injected, so that the injection capacity is improved.

The invention discloses a compressor system and a method for realizing stable boundary control of a gas compressor thereof, which can actively adjust parameters B of the system and realize switching of an instability mode of the gas compressor between surging and rotating stall by only depending on an independent, small and adjustable switching section on the premise of not modifying large basic hardware (such as a volute and a pipeline). According to the principle of the compressor system provided by the embodiment of the invention, the effective flow area is changed by adjusting the angle of the turbine guider, so that the stability boundary of an upstream gas compressor or a fan is actively expanded, low-cost and rapid adjustment of the stability of the gas compressor is realized, the research and development efficiency is improved, and the test period is effectively shortened. The compressor system provided by the embodiment of the invention has the characteristic of wide applicability, can be applied to an independent compression system part test environment, and can also be applied to a complex complete machine environment comprising a compression system.

The invention discloses a gas TPSA compression interstage purification integrated device control system and method. The system comprises a gas compression unit, an adsorption purification unit, a regeneration gas treatment unit and a control unit. The gas compression unit comprises a gas inlet pressure stabilizing valve, a gas compressor preceding stage, an interstage gas-gas heat exchanger, a compressor backward stage, an interstage pressure control valve and a backflow control valve, wherein the gas compressor preceding stage is used for pressurizing low-pressure raw gas and backflow regenerated gas to the pressure required by purification; compression heat of the interstage gas heat exchanger is used for preheating regenerated gas; the rear stage of the gas compressor is used for pressurizing the purified raw material gas to the pressure required by the downstream; the technical problems that a traditional TPSA gas purification device needs at least two compressors for staged compression, purification and compression systems are high in energy consumption, and loads are not easy to adjust are solved.

The utility model discloses a multi-stage compression gas compression system which comprises a hydraulic driving unit with fixed displacement, a multi-stage compression cylinder, a gas storage device, a gas pressure detection unit and a control unit, the multi-stage compression cylinder comprises a plurality of compression cylinders which are sequentially connected in series from the first stage to the last stage through gas conveying pipelines. The signal output end of the air pressure detection unit is connected with the signal input end of the control unit. The air pressure detection unit is used for detecting air pressure signals of the multi-stage compression cylinder and sending the air pressure signals to the control unit. And the control unit is used for controlling the working states of the other stages of compression cylinders except the first-stage compression cylinder in the multi-stage compression cylinders according to the air pressure signal, so that the other stages of compression cylinders except the first-stage compression cylinder in the multi-stage compression cylinders are put into compression work or quit compression work. According to the utility model, the cost and the control complexity of the gas compression system can be reduced, and the efficiency improvement and consumption reduction of the gas compression system can be realized.

The invention relates to a vehicle-mounted screw air compressor oil emulsification prevention method and system, a medium and a program product, and in the method, the running state parameters of a screw air compressor are monitored in real time, and a water vapor saturation pressure formula and a temperature and pressure coupling mathematical model are used for calculating saturation water vapor pressure and actual water vapor partial pressure respectively. When the actual water vapor partial pressure is larger than the saturated water vapor pressure force corrected by the safety coefficient, the system adjusts the oil way temperature control valve to reduce the lubricating oil flow of the oil cooler so as to increase the exhaust temperature. If the condensation risk still exists and the exhaust temperature does not reach the shutdown protection threshold value, the oil way temperature control valve continues to be adjusted; if the exhaust temperature reaches the shutdown protection threshold value, the actual water vapor partial pressure is reduced by reducing the rotating speed of the frequency converter. And after the condensation risk is eliminated, the current operation parameters are maintained. The method is used for reducing the possibility that water vapor reaches saturation in the compression system and liquid water is separated out, and the accuracy and stability of lubricating oil emulsification risk control of the air compressor under the variable load working condition are improved.

The invention discloses a rapid calculation method for flow field prediction of a compression system of a variable cycle engine, and the method comprises the steps: building a parameterized mapping model of valve opening and total pressure distribution based on a wall attachment turbulent jet theory; the fan state conversion process is dispersed into a plurality of quasi-steady-state working conditions according to the actuation angle range of a mode selection valve; constructing a total pressure distribution and recovery coefficient prediction module under each working condition by using the parameterized model; the prediction module is embedded into a fluid mechanics solver in the form of boundary conditions, numerical simulation of the state transition process is completed, and performance change data are obtained. According to the scheme, full-three-dimensional complex calculation is replaced by parameterized mapping, the efficiency and precision of variable circulating fan mode conversion performance analysis are remarkably improved, meanwhile, the calculation cost is reduced, and quick-response technical support is provided for compression system optimization design.

A method and apparatus for controlling compressors in a cascade vapor compression system. The process may include controlling the operation of a first compressor based on a constant band control, and controlling the operation of a second compressor based on a proportional band control. Controlling the first compressor based on the constant band control may include operating the compressor at a constant setting if first measurements are within a range associated with a first setpoint. It may also include proportionally adjusting the operation of the first compressor if the first measurements are outside the range. Further, controlling the second compressor based on the proportional band control may include operating the compressor based on one of a plurality of proportional bands, each proportional band having a different proportional factor. Controlling the second compressor operation may further include switching between these proportional bands based on a second measured parameter.

The invention discloses a gas and heat combined supply compression system operation optimization method based on energy efficiency evaluation, and relates to the technical field of heat supply system operation optimizing.Distributed sensors are deployed at equipment and pipeline nodes of a gas and heat combined supply compression system, and operation data of equipment and pipelines of the gas and heat combined supply compression system are collected in real time through the sensors; the operation data comprises equipment and pipeline node inlet and outlet temperature, pressure, flow, power consumption and operation state parameters of the gas and heat combined supply compression system. The operation data of the gas and heat combined supply compression system is collected in real time, a multi-dimensional dynamic energy efficiency evaluation model is constructed by using the operation data, core indexes such as waste heat recovery efficiency and waste heat utilization matching degree are accurately quantified, and accurate mastering of waste heat supply and demand states is achieved. The problem that waste heat supply is wrongly matched with actual heat requirements is effectively solved, and the effectiveness of waste heat recovery is improved.

The invention provides a system of a pumped storage coupled compressed air energy storage underground gas storage with an air cushion type surge shaft and an operation method. The system comprises a compressed air energy storage system and a pumped storage system. The interior of the water-gas co-containing bin is divided into an upper-layer gas storage chamber and a lower-layer water storage chamber through a flexible material. The air inlet end of the compression system is communicated with the second air path; the air outlet end of the compression system is connected to the air inlet of the upper-layer air storage chamber through a first air path; a first air valve is mounted on the first air path; a gas outlet of the upper-layer gas storage chamber is connected to the expansion unit through a third gas path, and a second gas valve is mounted on the third gas path; and a detection sensor is mounted in the water-gas co-containing bin. The stability and economical efficiency of the compressed air energy storage are improved, the compressed air utilization rate is increased, the combined operation mode of compressed air energy storage and pumped storage is simplified, the combined dispatching mode of novel energy storage is optimized, and then the safety and reliability of pumped storage are improved.

A method and device for determining a pneumatic instability boundary of a compression system in a complete machine environment, the method is applied to an engine test device, the engine test device comprises an engine body and a test modified turbine with a variable circulation sectional area, and the engine body comprises the compression system. The method comprises the steps that a compression system is controlled to enter a surge state by adjusting the circulation sectional area of a refitted turbine for testing and combining a fuel oil step method, or the compression system is controlled to enter the surge state by adjusting the circulation sectional area of the refitted turbine for testing and combining a high-pressure gas filling method; and determining an instability boundary point of the engine test device, and determining a pneumatic instability boundary of the compression system at the current rotating speed according to the instability boundary point. Therefore, the pneumatic instability boundary of the compression system in the whole machine environment is determined on the premise of not increasing the additional burden of a turbine and compression system components.

The invention discloses a compression system end area flow regulation and control method based on blade inner cooling under a low Reynolds number. Firstly, through calculation or measurement, a compression system end area three-dimensional flow field under different Reynolds numbers is obtained, and the end area loss variation degree is quantified. Then, revealing regulation and control rules of different isothermal cooling wall surface conditions on near-wall fluid physical property parameters, boundary layer growth rate and end region secondary flow migration intensity under a low Reynolds number, and establishing a correlation model of end region loss reduction and efficiency improvement and wall surface cooling intensity; and on the basis, a blade built-in convection cooling channel structure is designed, the cooling channel and blade surface flow heat characteristics are analyzed based on a conjugate heat transfer method, and inner cooling channel structure parameters are optimized until the wall surface temperature drop amplitude meets the preset requirement. And finally, checking the wall surface cooling effect, and measuring end region performance parameters during inner cooling regulation and control under a low Reynolds number to complete scheme verification. By introducing blade inner cooling, the flow characteristic of an end region can be remarkably improved on the premise that the structural complexity is not increased as much as possible, and stable and efficient operation of a compression system under the low Reynolds number is guaranteed.

To provide a control device, a compression system and a control method capable of reducing an execution frequency of oil return operation.SOLUTION: A control device comprises a control unit that, when turning on or off a solenoid valve provided in a circuit that returns oil discharged from a compressor together with a refrigerant to the inside of the compressor according to an amount of oil inside the compressor, turns on the solenoid valve when the amount of oil is equal to or less than a first threshold, and turns off the solenoid valve when the amount of oil is equal to or larger than a second threshold that is larger than the first threshold and a time that has elapsed since the solenoid valve was turned on exceeds a minimum on time.SELECTED DRAWING: Figure 1

The application provides a rotary impingement oblique flow centrifugal combined compressor and application thereof, and belongs to the technical field of turbine engines, and comprises an outer casing structure, an inner casing structure, a working mechanism and a diffuser mechanism, the outer casing structure and the inner casing structure are rotary bodies, the inner casing structure is located inside the outer casing structure, the inner casing structure and the outer casing structure form a working cavity, the working mechanism is installed in the working cavity and is used for pressurizing airflow. Compared with the compression mode of a conventional combined compressor, the application draws lessons from the pressurization mode of a supersonic inlet, and the Mach number of airflow relative to a rotating impeller reaches 2 or more through high-speed rotation; at this time, a series of weak oblique shock waves are constructed through the contraction of a passage, and a high-efficiency compression system is obtained through the pressurization of the shock wave system, the single-stage pressure ratio of the high-efficiency compression system is much higher than that of a conventional compressor, and the application has the advantages of compact structure, simple processing and long service life.

A heat exchanger for heating, ventilation, air conditioning and refrigeration (HVACamp; a compressor system of an HVACamp (R, R) system, the compressor system comprising one or more compressors configured to circulate a working fluid through the HVACamp; a vapor compression system of an R system, each compressor of the one or more compressors having a pre-rotating vane (PRV) and a variable geometry diffuser (VGD), the PRV and the VGD configured to operate to adjust a capacity of the compressor system. The compressor system further includes a controller having a memory and processing circuitry, where the memory includes instructions stored thereon that, when executed by the processing circuitry, cause the processing circuitry to: determine a head coefficient for each compressor of the one or more compressors, and determine a head coefficient for each compressor of the one or more compressors; determining a compressor lift for each of the one or more compressors based at least in part on the head coefficient, comparing the compressor lift for each of the one or more compressors to a low lift threshold and a high lift threshold, and operating each of the one or more compressors in a first mode or a second mode based on a comparison of the compressor lift to the low lift threshold and the high lift threshold.

A method for controlling a vapor compression system (1) is disclosed. The vapor compression system (1) includes a compressor unit (2), a heat exchanger (5), a receiver (7), an expansion device (8), and an evaporator (9) arranged in a refrigerant path. The compressor unit includes at least one main compressor (3) and at least one receiver compressor (4). The vapor compression system (1) further includes a bypass valve (12) that fluidly interconnects the gas outlet (10) of the receiver (7) with the main compressor / multiple main compressors (3). A first pressure setpoint and a second pressure setpoint for the current pressure in the receiver (7) are defined, the second pressure setpoint being higher than the first pressure setpoint. When the load demand of the vapor compression system (1) exceeds the maximum capacity of the receiver compressor / multiple receiver compressors (4), the opening of the bypass valve (12) is controlled to adjust the current pressure in the receiver (7) according to the first pressure setpoint, and to reach the first pressure setpoint. When the receiver compressor / multiple receiver compressors (4) is operating and the load demand of the vapor compression system (1) is lower than the maximum capacity of the receiver compressor / multiple receiver compressors (4), the opening of the bypass valve (12) is controlled to adjust the current pressure in the receiver (7) according to the second pressure setpoint, and to reach the second pressure setpoint.

A vapor compression system includes a compressor including a compression stage for compressing a working fluid; a first heat exchanger located downstream of the compressor, the first heat exchanger receiving and cooling a working fluid; a second heat exchanger located downstream of the first heat exchanger and upstream of the compressor, the second heat exchanger receiving and heating the working fluid; and a reservoir positioned between the second heat exchanger and the compression stage. The reservoir defines an internal volume for containing a vapor phase and a liquid phase of the working fluid, and the reservoir includes an inlet to receive the working fluid from the second heat exchanger and an outlet to allow the vapor phase of the working fluid to exit the reservoir and flow toward the compression stage. The reservoir atomizes a liquid phase of the working fluid into droplets and introduces the droplets into a vapor phase of the working fluid exiting the reservoir.

This utility model relates to the field of straw processing technology, and in particular to a straw compression system. It includes a placement platform, a fixed cylinder fixed to the top of the placement platform, a feeding plate fixed to one end of the outer side of the fixed cylinder, and a first fixed plate fixed to the bottom end of the outer side of the fixed cylinder away from the feeding plate. Both the feeding plate and the first fixed plate are connected to the fixed cylinder. A crushing structure is provided on the inner side of the feeding plate, and heat insulation components are provided on the inner sides of both the feeding plate and the first fixed plate. A compression component is provided at the bottom of the first fixed plate. The straw compression system provided by this utility model, through the design of the crushing component, can further refine the straw processing so that the straw can be compressed precisely. The design of the adjusting mechanism can adjust the dryness and moisture of the straw to improve the quality of the straw blocks. The design of the heat insulation component can better insulate the inner side of the fixed cylinder without affecting the straw's entry and exit, facilitating the drying of the heating element.

The invention discloses a hydrogen variable-stage compression reciprocating piston type compressor unit, and relates to the technical field of hydrogen compression. Comprising a rack, a first-stage reciprocating piston type compressor, a second-stage reciprocating piston type compressor and a third-stage reciprocating piston type compressor which are mounted at the bottom of the rack in the Y-axis direction, and a variable-stage air guide pipe group mounted at the air inlet end of a cylinder body of the first-stage reciprocating piston type compressor, and a second-stage air inlet pipe is arranged between the air outlet end of the air storage tank of the first-stage reciprocating piston type compressor and the air inlet end of the cylinder body of the second-stage reciprocating piston type compressor. The high-pressure hydrogen is allowed to be directly switched into the low-pressure stage, the middle-pressure stage and the high-pressure stage of the compressor unit through dynamic dispatching of the valves of the variable-stage gas guide pipe set, so that the residual high-pressure potential energy of the trailer is directly converted into effective initial work of a compression system, and the fatal energy fault of first pressure relief and then low-pressure full-pressure-difference compression in a traditional scheme is avoided; potential energy wasted by the pressure reducing valve originally is directly inherited and utilized by the compressor.

The compression system (100) has a compressor (150) with an inlet duct (110) and an outlet duct (120) and an anti-surge recirculation loop (140) which may recirculate fluid from the outlet duct (120) to the inlet duct (110) and regulate the flow along the anti-surge recirculation loop (140) through a throttling valve (145). The compression system (100) is further provided with another throttling valve (155) directly located at the compressor outlet flange (112), preferably at a distance from the compressor outlet flange (112) which is less than three times the inner diameter of the outlet duct (120), and a control unit (160) which controls and regulates the opening and closing of the throttling valves (145, 155). The combined control of the opening / closing of the two throttling valves (145, 155) allows to find a stable operating point of the compressor (150) which is on the left of the expecting surge limit line of the machine, extending thus the stable operation conditions of the compressor (150) and protecting the compressor (150) from the risk of surge.

A gas turbine engine has a compression system blade ratio defined as the ratio of the height of a fan blade to the height of the most downstream compressor blade in the range of from 45 to 95. This results in an optimum balance between installation benefits, operability, maintenance requirements and engine efficiency when the gas turbine engine is installed on an aircraft.

The application belongs to the technical field of compressors and provides a compressor and a compression system.The compressor comprises a shell containing a compression cavity, the shell comprises a first shell provided with a first air inlet and a second shell provided with a second air inlet, the shell is provided with a radial exhaust port, the radial exhaust port is communicated with the compression cavity, a rotor assembly is installed in the compression cavity, the rotor assembly comprises a male rotor assembly and a female rotor assembly, the male rotor assembly comprises a right-handed male rotor and a left-handed male rotor which are symmetrically arranged, the female rotor assembly comprises a right-handed female rotor and a left-handed female rotor which are symmetrically arranged, the right-handed male rotor and the left-handed female rotor are engaged to form a first compression pair, and the left-handed male rotor and the right-handed female rotor are engaged to form a second compression pair.The symmetric structure design eliminates a single high-pressure area, the gas forces generated by the two compression pairs are offset to each other, the vibration and wear are reduced, and the operation stability and reliability of the compressor are improved.

The invention relates to overheat controlled thermal storage. A vapor compression system includes a compressor, a condenser, an expansion device, and an evaporator fluidly connected to form a closed fluid circuit having a working fluid circulating therethrough. The thermal storage device includes a storage material, and the thermal storage device is thermally coupled to the closed fluid circuit downstream of the expansion device with respect to the flow of the working fluid. The vapor compression system is controllable such that the heat storage device is operable to both store and release heat when the working fluid circulates through the closed fluid circuit in a given direction.

Embodiments of the present disclosure are directed toward purge units of vapor compression systems, and methods of control thereof, that improve efficiency by selectively activating and deactivating the purge unit in response to one or more conditions to, for example, enable refrigerant-to-air ratios within the purge unit within certain industry standards while still minimizing the durations of the purge cycles. For example, in certain embodiments, these conditions may include conditions within the chiller condenser, time since last purge activation, time since last venting of non-condensables, and combinations thereof. By reducing an amount of time that the purge unit would be active without removing a substantial amount non-condensables from the vapor compression system, present embodiments reduce the power consumption of the purge unit, as well as the vapor compression system as a whole, while still being responsive to prevent or mitigate a loss of efficiency due to a substantial accumulation of non-condensables in the condenser of the vapor compression system.

The invention discloses a water vapor compression system and a bearing gas supply method, the water vapor compression system comprises: a water vapor compressor comprising a gas bearing, a gas supply port and a gas exhaust port for respectively supplying gas to and exhausting gas from the gas bearing, a water vapor inlet for inputting water vapor to be compressed, and a water vapor outlet for outputting compressed water vapor; a first tank for storing compressed gas for the gas bearing, the first tank including a first port and a second port connected to the gas supply port and the gas discharge port, respectively; the steam driving air pump comprises a first driving end used for providing driving force and a first air pumping end used for pumping air and discharging air, the first driving end comprises a steam inlet connected with the steam outlet, and the first air pumping end is arranged on a connecting pipeline between the first opening and the air supply opening; the first air pumping end comprises a first air extraction opening connected with the first opening and a first air outlet connected with the air supply opening.

The invention relates to the technical field of energy power, and particularly discloses a power generation device for generating water vapor energy through an internal combustion engine set. The device comprises a compression starting system, a heat energy exchange system, a steam power system, a residual pressure and circulation system and an intelligent management system. A compression system is started to compress air to generate high-temperature and high-pressure gas; the heat energy exchange system uses the gas to heat water into high-pressure steam; the steam power system is driven by steam to generate electricity; the residual pressure and circulating system recycles dead steam residual pressure to drive air inlet pressurization, heat preservation is conducted through waste heat, and steam is condensed into water to be recycled; and the intelligent management system performs cooperative control. Water vapor autonomous power generation is achieved through physical compression and countercurrent flow heat exchange, energy gradient utilization and working medium closed-loop circulation are achieved, and the device has the advantages of being efficient, clean and capable of running continuously.

The invention relates to a method and apparatus for controlling a compressor in a cascade vapour compression system. The process may include controlling operation of the first compressor based on constant band control, and controlling operation of the second compressor based on proportional band control. If the first measurement is within a range associated with the first setpoint, controlling the first compressor based on the constant band control may include operating the compressor at a constant setting. If the first measurement is outside the range, it may also include proportionally adjusting operation of the first compressor. Further, controlling the second compressor based on proportional band control may include operating the compressor based on one of a plurality of proportional bands, each proportional band having a different proportionality coefficient. Controlling second compressor operation may also include switching between the proportional bands based on a second measured parameter.

The invention is suitable for the technical field of compressors, and provides a compressor and a compression system. The compressor comprises a shell containing a compression cavity, the shell comprises a first shell body provided with a first air inlet and a second shell body provided with a second air inlet, the first shell body and the second shell body are symmetrically arranged, a radial exhaust port is formed in the shell, and the radial exhaust port is communicated with the compression cavity; the rotor assembly is mounted in the compression cavity and comprises a male rotor assembly and a female rotor assembly, the male rotor assembly comprises a right-handed male rotor and a left-handed male rotor which are symmetrically arranged, the female rotor assembly comprises a right-handed female rotor and a left-handed female rotor which are symmetrically arranged, and the right-handed male rotor and the left-handed female rotor are meshed to form a first compression pair; and the left-handed male rotor and the right-handed female rotor are meshed to form a second compression pair. Due to the symmetrical structural design, a single-end high-pressure area is eliminated, gas force generated by two compression pairs is offset, vibration and abrasion are reduced, and the operation stability and reliability of the compressor are improved.

The invention provides a high-pressure gas membrane rupture pressure measuring device and a measuring method thereof, and belongs to the technical field of pressure measurement. The measuring device comprises a pressure generation system, a gas compression system, a gas injection system, a pressure measuring system and a diaphragm clamping system. The piston divides the cavity into a hydraulic cavity and a gas compression cavity, and the piston is hydraulically driven to compress the pre-filled gas, so that the diaphragm is broken. The pressure measurement system records pressure-time data in real time, and a sliding window average algorithm is adopted to extract a membrane rupture pressure peak value. According to the technical scheme, inert gas is used, initiating explosive devices are not used, membrane rupture energy is only gas expansion, the protection box can absorb fragments, and explosion-proof transformation is not needed in a laboratory. And the smoothed unique membrane rupture pressure value is output through a sliding window averaging algorithm, and manual reading errors are eliminated. According to the technical scheme, the device is compact in structure, safe to operate, rapid in testing and suitable for accurately measuring the diaphragm rupture pressure of the gas gun diaphragm in a conventional laboratory.

The invention relates to a turbulence modeling method suitable for complex flow of an aerospace vehicle compression system, and belongs to the field of aerospace vehicle turbulence modeling. According to the distribution rule of the normalized velocity helicities of the LES flow field at the blade tip of the gas compressor rotor in the aerospace vehicle, constructing a normalized velocity helicities model, namely an h model; according to an LES flow field at the root of a stator of a gas compressor in an aerospace vehicle, a second-order explicit anisotropic Reynolds stress model, namely a Q model, is constructed; according to the h model and the Q model, a novel RANS turbulence model, namely a Wilcox2006k-omega-h-Q model, for reasonably capturing blade tip gap leakage flow and corner separation flow is constructed, and turbulence modeling suitable for complex flow of an aerospace vehicle compression system is completed; according to the method, the novel RANS turbulence model capable of reasonably capturing the blade tip clearance leakage flow and the corner separation flow is constructed, and high-fidelity numerical simulation solution of the internal flow of the compression system of the aerospace vehicle is achieved.

Disclosed are a device for producing liquid from flue gas with low energy consumption and a method for using the same. The device includes a CO2 and N2 low-temperature medium-pressure adsorption system, an energy utilization system, a low-temperature filtration gas low-temperature compression system, a CO2 low-temperature purification system, and a nitrogen liquid device system; the systems are interconnected through pipelines and valves; the CO2 and N2 low-temperature medium-pressure adsorption system includes a flue gas cooler, a first gas-liquid separator, a compression system, a drying system, a gas expander system, and a low-temperature medium-pressure adsorption device; the energy utilization system includes an electric heater, a CO2 compressor, a heat utilizer, and a second cooler; the low-temperature filtration gas low-temperature compression system includes a low-temperature compressor and a CO2 low-temperature purification system.