Graded cooling type compressed CO2 energy storage power generation system coupled with chemical waste heat

Abstract

The invention discloses a staged cooling type compressed CO2 energy storage power generation system coupled with chemical waste heat, and the system comprises a chemical reaction kettle waste heat collection module which is used for providing a driving heat source for a hot water type lithium bromide refrigeration subsystem and supplementing heat for heating high-pressure liquid CO2 to a supercritical state, and adopts a waste heat double-path dynamic distribution mechanism; the three-section type staged cooling module is used for condensing gaseous CO2 into low-pressure liquid CO2 by using the waste heat provided by the chemical reaction kettle waste heat collection module, and adopts a three-section type intelligent cooling system with the functions of multi-parameter sensing, inter-section linkage modeling and self-adaptive algorithm adjustment; and the transcritical liquid-liquid compression CO2 energy storage module is used for compressing the low-pressure liquid CO2 obtained by cooling of the three-section type staged cooling module into a high-pressure liquid CO2, and the transcritical liquid-liquid compression CO2 energy storage module adopts a two-stage liquid-liquid compression electric pump as supercharging equipment to directly compress the low-pressure liquid CO2. Efficient utilization of waste heat resources in the chemical production process can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy storage and energy comprehensive utilization, in particular to a graded cooling type compressed CO2 energy storage and power generation system coupled with chemical industry waste heat. BACKGROUND

[0002] With the transformation of global energy structure to clean and low carbon, the chemical industry as a high energy consumption field, a large amount of process waste heat generated in the production process becomes an important energy resource to be tapped. According to data, chemical industry waste heat resources account for 30%-50% of total energy consumption, among which the proportion of medium and low temperature waste heat is high, but the current recovery and utilization rate of this part of waste heat is low, and a large amount of waste heat is directly discharged through cooling devices, which not only causes energy waste, but also increases the risk of environmental heat pollution.

[0003] At the same time, compressed carbon dioxide energy storage technology has become a key development direction in the field of new energy storage due to its high energy storage density, high system efficiency and environmental friendliness. Among them, the transcritical liquid-liquid compressed CO2 energy storage and power generation system, relying on the technical characteristics of 2-7 MPa liquid CO2 storage on the low pressure side and 10-15 MPa supercritical CO2 power generation on the high pressure side, has the outstanding advantages of small system volume and fast response speed compared with traditional air energy storage and pumped storage technology, which is more suitable for the actual needs of distributed energy storage of industrial users, and has significant application potential in the energy optimization scene of chemical enterprises.

[0004] However, the current mainstream compressed CO2 energy storage and power generation system still faces three major technical bottlenecks in actual application: first, the energy consumption of low pressure side gas compression is high, and the integration of liquid-liquid compression electric pump is insufficient; second, the synergy between chemical waste heat and energy storage system is weak, and the waste heat utilization efficiency is low; third, the cooling method is single and the effect is poor, and the graded cooling mechanism is missing, which restricts its collaborative adaptation with the energy system of chemical enterprises. SUMMARY

[0005] In view of the above problems, the purpose of the present application is to provide a graded cooling type compressed CO2 energy storage and power generation system coupled with chemical waste heat, which can realize efficient utilization of waste heat resources in the chemical production process and peak load shifting of electric energy, and help the low-carbon and efficient upgrading of the energy system of the chemical industry.

[0006] The following technical solutions are realized: A staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from a chemical plant is disclosed. The system includes a waste heat acquisition module for a chemical reactor, a three-stage staged cooling module, and a transcritical liquid-liquid compressed CO2 energy storage module. The chemical reactor waste heat acquisition module provides a driving heat source for the hot water-type lithium bromide refrigeration subsystem and replenishes heat for heating high-pressure liquid CO2 to a supercritical state. It employs a dual-path dynamic waste heat distribution mechanism, with manually and electrically controlled waste heat distribution valve groups to guide the waste heat distribution logic in both energy storage and release modes. In energy storage mode, waste heat from the chemical reactor is preferentially transferred to the high-pressure heat exchanger; in release mode, waste heat from the chemical reactor is preferentially transferred to the hot water-type lithium bromide refrigeration subsystem. The three-stage staged cooling module utilizes the waste heat provided by the chemical reactor waste heat acquisition module to condense gaseous CO2 into a low-pressure liquid state. It employs a three-stage intelligent cooling system with multi-parameter sensing, inter-stage linkage modeling, and adaptive algorithm adjustment functions. The first stage first acquires the flow rate Q of CO2 at the outlet of the supercritical CO2 turbine. 透出 Temperature T 透出 and pressure P 透出 And the CO2 flow rate Q at the outlet of the two-stage liquid-liquid compression pump 电泵出 and temperature T 电泵出 Then, the regenerated heat Q of the regenerating heat exchanger is calculated based on the dynamic heat transfer model. 回热 Simultaneously, the baffle angle is dynamically adjusted using an adaptive baffle adjustment algorithm; the second stage first collects the CO2 outlet temperature T3 and flow rate Q3 of the regenerating heat exchanger, as well as the circulating water inlet and outlet temperatures T of the circulating water cooler. 冷进 and T 冷出 Then, the minimum circulating water flow rate Q required by the circulating water cooler is calculated based on the dynamic cooling flow rate model. 冷 Simultaneously, the circulating water flow rate of the circulating water cooler is adjusted in real time using a PID flow regulation algorithm; the third stage first collects the CO2 outlet temperature T4, flow rate Q4, and pressure P4 of the circulating water cooler, as well as the chilled water outlet temperature T of the hot water lithium bromide refrigeration subsystem. 冻 and driving hot water flow rate Q 热 Then, based on the coupled model of cooling capacity and waste heat demand, the cooling capacity Q required for the hot water lithium bromide refrigeration subsystem to condense CO2 is calculated. 制 and driving hot water flow rate Q 热 Simultaneously, the flow rate of the driving hot water is adjusted in real time through a fuzzy control algorithm. The transcritical liquid-liquid compression CO2 energy storage module is used to compress the low-pressure liquid CO2 obtained by the three-stage staged cooling module to a high-pressure liquid state. It uses a two-stage liquid-liquid compression electric pump as a pressurization device to directly compress the low-pressure liquid CO2. The compressed CO2 directly enters the shell side of the regenerator heat exchanger and performs countercurrent heat exchange with the gaseous CO2 at the outlet of the supercritical CO2 turbine. This invention system can realize the efficient utilization of waste heat resources in chemical production processes and peak shaving and valley filling of electricity.

[0007] Preferably, both the energy storage mode and the energy release mode are equipped with electromagnetic flow meters and platinum resistance temperature sensors in the waste heat distribution path. The electromagnetic flow meters and platinum resistance temperature sensors are used to acquire the waste heat flow rate and inlet temperature of the hot water lithium bromide refrigeration subsystem and the high-pressure heat exchanger in real time, respectively. By configuring electromagnetic flow meters and platinum resistance temperature sensors, real-time linkage adjustment between waste heat demand and load conditions can be achieved, breaking through the limitations of traditional static waste heat distribution.

[0008] Preferably, in energy release mode, when the waste heat flow rate and inlet temperature of the collected hot water lithium bromide refrigeration subsystem are below a threshold, the system's refrigeration priority compensation mechanism will be triggered; in energy storage mode, when the waste heat flow rate and inlet temperature of the collected high-pressure heat exchanger are below a threshold, the system's energy storage priority compensation mechanism will be triggered. Through this real-time adjustment mechanism, long-term stable operation of the system can be achieved.

[0009] Preferably, after meeting the minimum waste heat requirements in both energy storage and energy release modes, the remaining allocable waste heat resources ΔQ are allocated according to an allocation function. The allocation function in the energy release mode is: Q1 = Q1_min + ΔQ × K1 × (COP) 实时 / COP 额定 The allocation function under the energy storage mode is: Q2 = Q2_min + ΔQ × K2 × (η) 换热实时 / η 换热额定 ), where Q1 and Q2 are the waste heat resources allocated to the two modes, Q1_min and Q2_min are the minimum waste heat requirements of the two modes, K1 and K2 are the mode weighting coefficients, and COP 实时 The current coefficient of performance (COP) for the hot water lithium bromide refrigeration subsystem. 额定 η is the rated coefficient of performance for a hot water lithium bromide refrigeration subsystem. 换热实时 η represents the current heat exchange efficiency of the high-pressure heat exchanger. 换热额定 This refers to the rated heat exchange efficiency of the high-pressure heat exchanger. By allocating the remaining distributable waste heat resources, the utilization rate of waste heat resources can be improved.

[0010] Preferably, in the first segment, the dynamic heat transfer model is: Q 回热 =k×A×ΔTlm, where k is the overall heat transfer coefficient, A is the effective heat transfer area, and ΔTlm is the logarithmic mean temperature difference; the adaptive baffle adjustment algorithm uses a fuzzy PID controller, outputting a baffle angle adjustment command with the set regenerative efficiency value as the target, and adjusting the baffle angle via a servo motor. By adjusting the baffle angle in real time, stable regenerative efficiency can be ensured.

[0011] Preferably, in the second stage, the dynamic cooling flow model is: Q 冷 =(Q3×ρ×cp×ΔT CO2 ) / (ρ冷 ×cp 冷 ×ΔT 冷 ), ΔT CO2 ρ is the difference between the outlet CO2 temperature and the target temperature of the regenerative heat exchanger, where ρ is the CO2 density and cp is the specific heat capacity of gaseous CO2. 冷 For the density of circulating water, cp 冷 ΔT is the specific heat capacity of circulating water. 冷 The circulating water temperature difference between the inlet and outlet of the circulating water cooler; the PID flow regulation algorithm uses Q... 冷 The calculated value is the target value. The actual flow rate of the circulating water is controlled by adjusting the opening of the electric regulating valve in the cooling water pipeline. By controlling the actual flow rate of the circulating water, the power consumption of the circulating water pump can be reduced.

[0012] Preferably, in the third segment, the coupling model between cooling capacity and waste heat demand is: Q 制 =(Q4 / 3600)×ρ 气态 ×r, Q 热 =Q 制 / (COP×ρ 热 ×cp 热 ×ΔT 热 ), ρ 气态 Let ρ be the density of gaseous CO2, r be the latent heat of phase change, COP be the coefficient of performance of lithium bromide, and ρ be the density of gaseous CO2. 热 To drive the density of hot water, cp 热 To drive the specific heat capacity of hot water, ΔT 热 To drive the hot water temperature difference, a fuzzy control algorithm is used to dynamically adjust the opening of the hot water regulating valve. By dynamically adjusting the opening of the hot water regulating valve, waste heat from the driving process can be avoided.

[0013] Preferably, the two-stage liquid-liquid compression pump adopts an asymmetric compression structure of one stage + two stages. The first stage compression chamber is used to adapt to liquid CO2 with a lower compressibility coefficient, and the second stage compression chamber is used to adapt to liquid CO2 with a higher compressibility coefficient. By adopting the asymmetric compression structure of one stage + two stages, the interstage heat load imbalance caused by proportional compression can be avoided.

[0014] Preferably, the two-stage liquid-liquid compression pump is equipped with a segmented jacketed cooling channel, dividing the pump jacket into two sections: the first-stage compression chamber corresponds to the low-flow-rate channel, and the second-stage compression chamber corresponds to the high-flow-rate channel. By setting the segmented jacketed cooling channel, the pump operating temperature can be ensured to remain stable at 45±2℃.

[0015] Preferably, a buffer chamber communicating with a low-pressure liquid storage tank is provided outside the mechanical seal of the two-stage liquid-liquid compression pump to reduce the pressure difference across the sealing surface. By providing a buffer chamber communicating with the low-pressure liquid storage tank, the leakage rate of the mechanical seal can be reduced.

[0016] The beneficial effects of this invention compared to the prior art are: The technical solution of this invention employs a dual-path dynamic distribution mechanism for waste heat in the chemical reactor waste heat acquisition module, enabling real-time linkage adjustment between waste heat demand and load conditions, breaking through the limitations of traditional static waste heat distribution and improving waste heat utilization. The three-stage graded cooling module utilizes a three-stage intelligent cooling system with multi-parameter sensing, inter-stage linkage modeling, and adaptive algorithm adjustment functions, achieving dynamic matching between CO2 cooling capacity and CO2 operating conditions, improving CO2 condensation efficiency and avoiding large fluctuations in condensation efficiency. The transcritical liquid-liquid compression CO2 energy storage module uses a two-stage non-uniform liquid-liquid compression electric pump as a booster, ensuring that liquid CO2 remains liquid throughout the pressurization process, completely avoiding latent heat loss due to phase change in traditional compressor systems, improving pump compression efficiency. Furthermore, by combining it with a segmented jacketed intelligent cooling channel, the mechanical seal leakage rate can be reduced. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry. Explanation of reference numerals in the attached diagram: 1. Chemical reactor; 2. Hot water heat exchanger; 3. Waste heat circulation pump; 4. Waste heat distribution valve group; 5. Low-pressure CO2 liquid storage tank; 6. Two-stage liquid-liquid compression electric pump; 7. High-pressure CO2 liquid storage tank; 8. High-pressure heat exchanger; 9. Regenerative heat exchanger; 10. Supercritical CO2 turbine; 11. Generator; 12. Circulating water cooler; 13. Hot water lithium bromide refrigeration subsystem; 14. Circulating water pump; 15. Lithium bromide unit heat source pump. Detailed Implementation

[0018] The following will refer to the appendices in the embodiments of the present invention. Figure 1 The technical solutions in the embodiments of the present invention will be described in detail below.

[0019] like Figure 1The diagram shows a structural schematic of a staged cooling compression CO2 energy storage and power generation system coupled with waste heat from chemical production. The system includes: a chemical reactor, a hot water heat exchanger, a waste heat circulation pump, a waste heat distribution valve group, a low-pressure CO2 liquid storage tank, a two-stage liquid-liquid compression electric pump, a high-pressure CO2 liquid storage tank, a high-pressure heat exchanger, a regenerative heat exchanger, a supercritical CO2 turbine, a generator, a circulating water cooler, a hot water lithium bromide refrigeration subsystem, a circulating water pump, and a lithium bromide unit heat source pump. The hot water lithium bromide refrigeration subsystem includes: a lithium bromide refrigeration system for cooling with lithium bromide, a cold tank for storing the cooling capacity generated by the lithium bromide refrigeration system, and a cooling heat exchanger for transferring the cooling capacity generated by the lithium bromide refrigeration system to the circulating water. The system consists of three parts: a chemical reactor waste heat acquisition module, a three-stage staged cooling module, and a transcritical liquid-liquid compression CO2 energy storage module. It enables efficient utilization of waste heat resources during chemical production and peak shaving and valley filling of electricity.

[0020] The system specifically includes the following: The waste heat collection module for the chemical reactor is used to provide a driving heat source for the hot water-type lithium bromide refrigeration subsystem and to supplement heat for heating high-pressure liquid CO2 to a supercritical state. It employs a dual-path dynamic waste heat distribution mechanism, with a manually and electrically controlled waste heat distribution valve group to govern the waste heat distribution logic in both energy storage and release modes. It is equipped with a hot water heat exchanger, a waste heat circulating water pump, and polyurethane insulated pipes. The waste heat from the chemical reactor, after being pressurized by the waste heat circulating pump, is transferred to the shell side of the hot water heat exchanger through the waste heat distribution valve group. Circulating water flows through the tube side of the hot water heat exchanger, and the chemical reactor heats the waste heat through counter-current heat exchange. Waste heat from the reactor is transferred to circulating water, forming high-temperature hot water with a supply temperature of 115℃ and a return temperature of 105℃. The 115℃ high-temperature hot water is divided into two streams to provide a stable heat source for the corresponding equipment. In energy storage mode, the waste heat from the chemical reactor is preferentially transferred to the high-pressure heat exchanger to ensure that the supercritical CO2 can be accurately heated to the corresponding temperature. In energy release mode, the waste heat from the chemical reactor is preferentially transferred to the hot water-type lithium bromide refrigeration subsystem, and then transferred to the hot water-type lithium bromide refrigeration subsystem through the lithium bromide unit heat source pump to ensure that the low-pressure CO2 can be cooled to the corresponding temperature.

[0021] Specifically, in energy release mode, the minimum required parameters for the hot water lithium bromide refrigeration subsystem include: a minimum temperature threshold of 90℃, below which the lithium bromide solution risks crystallization, and the refrigeration COP < 0.8, failing to meet design requirements; and a minimum flow rate threshold of 120 m³ / h. 3 / h, to ensure a heat exchanger heat exchange area of ​​180m² 2 Effective utilization is crucial to avoid solution degradation caused by localized overheating; the constraints are: inlet temperature ≥ 90℃ and flow rate ≥ 120 m³ / h. 3At a rate of [value missing] / h, it can maintain 70% of the rated cooling capacity of 550kW, meeting subsequent deep cooling requirements. In energy storage mode, the minimum required parameters for the high-pressure heat exchanger include: a minimum temperature threshold of 100℃; below this temperature, CO2 cannot reach the supercritical state at 7.38MPa, and the heat exchange efficiency will drop sharply by more than 30% due to phase change; and a minimum flow rate threshold of 300m³ / h. 3 / h, to ensure that the temperature rise rate of high-pressure liquid CO2 from 45℃ to 105℃ is ≥2℃ / s, meeting the energy storage power requirements; the constraints are: inlet temperature ≥100℃ and flow rate ≥300m³ / h. 3 At a rate of / h, CO2 can be kept in a stable supercritical state, avoiding power fluctuations caused by insufficient working fluid parameters during turbine power generation.

[0022] In this embodiment, both the energy storage mode and the energy release mode are equipped with electromagnetic flow meters and platinum resistance temperature sensors in the waste heat distribution path. The electromagnetic flow meters and platinum resistance temperature sensors are used to obtain the waste heat flow rates Q1 and Q2 and the inlet temperatures T1 and T2 of the hot water lithium bromide refrigeration subsystem and the high-pressure heat exchanger in real time, respectively, and the data is refreshed every 100ms, thereby enabling real-time linkage adjustment between waste heat demand and load conditions, breaking through the limitations of traditional static waste heat distribution.

[0023] In this embodiment, after meeting the minimum waste heat requirements in both energy storage and energy release modes, the remaining allocable waste heat resources ΔQ are allocated according to an allocation function. The allocation function in energy release mode is: Q1 = Q1_min + ΔQ × K1 × (COP) 实时 / COP 额定 The allocation function under the energy storage mode is: Q2 = Q2_min + ΔQ × K2 × (η) 换热实时 / η 换热额定 In this context, Q1 and Q2 represent the waste heat resources allocated to the two modes, Q1_min and Q2_min represent the minimum waste heat requirements for the two modes, K1 and K2 are mode weighting coefficients, and K1+K2=1, COP. 实时 The current coefficient of performance (COP) for the hot water lithium bromide refrigeration subsystem. 额定 η is the rated coefficient of performance for a hot water lithium bromide refrigeration subsystem. 换热实时 η represents the current heat exchange efficiency of the high-pressure heat exchanger. 换热额定 To achieve the rated heat exchange efficiency of the high-pressure heat exchanger, the utilization rate of waste heat resources can be improved by allocating the remaining distributable waste heat resources.

[0024] The calculation method for the mode weighting coefficient K2 in the energy storage mode is as follows: The mode weighting coefficient K1 in the energy release mode is calculated as follows: K1 = 1 - K2, where T2 CO2出T1 is the CO2 temperature at the outlet of the high-pressure heat exchanger, and T2 is the waste heat inlet temperature of the high-pressure heat exchanger.

[0025] In this embodiment, under the energy release mode, when the waste heat flow rate and inlet temperature of the collected hot water lithium bromide refrigeration subsystem are lower than the threshold, the system's refrigeration priority compensation mechanism will be triggered, temporarily increasing K1 to 0.8 until the waste heat flow rate and inlet temperature parameters recover to above the threshold. Under the energy storage mode, when the waste heat flow rate and inlet temperature of the collected high-pressure heat exchanger are lower than the threshold, the system's energy storage priority compensation mechanism will be triggered, temporarily increasing K2 to 0.8, and simultaneously reducing the load of the lithium bromide unit's heat source pump. At the same time, the electric regulating valve of the waste heat distribution valve group automatically adjusts the valve opening according to the calculation results to increase or decrease the waste heat flow rate. Its response time is ≤2s. The valve body is made of 316L material, which is resistant to corrosion from hot water at 115℃, to ensure the stability of the CO2 supercritical state and achieve long-term stable operation of the system.

[0026] The three-stage staged cooling module utilizes waste heat from the waste heat collection module of the chemical reactor to condense gaseous CO2 into a low-pressure liquid state. It employs a three-stage intelligent cooling system with multi-parameter sensing, inter-stage linkage modeling, and adaptive algorithm adjustment capabilities. The first stage collects the CO2 flow rate Q at the outlet of the supercritical CO2 turbine. 透出 Temperature T 透出 and pressure P 透出 And the CO2 flow rate Q at the outlet of the two-stage liquid-liquid compression pump 电泵出 and temperature T 电泵出 Then, the regenerated heat Q of the regenerating heat exchanger is calculated based on the dynamic heat transfer model. 回热 Simultaneously, the baffle angle is dynamically adjusted using an adaptive baffle adjustment algorithm; the second stage first collects the CO2 outlet temperature T3 and flow rate Q3 of the regenerating heat exchanger, as well as the circulating water inlet and outlet temperatures T of the circulating water cooler. 冷进 and T 冷出 Then, the minimum circulating water flow rate Q required by the circulating water cooler is calculated based on the dynamic cooling flow rate model. 冷 Simultaneously, the circulating water flow rate of the circulating water cooler is adjusted in real time using a PID flow regulation algorithm; the third stage first collects the CO2 outlet temperature T4, flow rate Q4, and pressure P4 of the circulating water cooler, as well as the chilled water outlet temperature T of the hot water lithium bromide refrigeration subsystem. 冻 and driving hot water flow rate Q 热 Then, based on the coupled model of cooling capacity and waste heat demand, the cooling capacity Q required for the hot water lithium bromide refrigeration subsystem to condense CO2 is calculated. 制 and driving hot water flow rate Q 热Simultaneously, the hot water flow rate is adjusted in real time through a fuzzy control algorithm. Multi-dimensional parameters, including flow rate, temperature, and pressure, are acquired via an electromagnetic flowmeter, temperature sensor, and pressure transmitter, respectively. PID stands for Proportional-Integral-Derivative Control, a method that calculates the output based on a linear combination of proportional, integral, and derivative terms according to the error between the setpoint and the actual value. Fuzzy PID controllers, on the other hand, combine PID control algorithms with fuzzy logic, primarily addressing the needs for dynamic response and parameter adaptation in complex industrial scenarios. Their core functionality involves linking with a traditional PID controller via a fuzzification module to achieve online parameter adjustment. Fuzzy logic is a mathematical framework and way of thinking used to handle uncertainty and fuzzy concepts.

[0027] The circulating water cooler uses a shell-and-tube heat exchanger. Low-pressure gaseous CO2, reheated by a regenerating heat exchanger, is introduced into the tube side, while industrial circulating water supplied by a circulating water pump is introduced into the shell side. Through forced convection heat exchange between the tubes and shell, the low-pressure gaseous CO2 further releases heat and lowers its temperature, laying the foundation for the subsequent condensation of CO2 into liquid. At the same time, the shell side of the circulating water cooler is equipped with an automatic drain valve and an air vent valve to prevent scale buildup and air resistance from affecting heat exchange efficiency. The automatic drain valve has a drain cycle of 12 hours and a single drain time of 30 seconds. The air vent valve needs to be opened manually to remove air from the shell side.

[0028] The lithium bromide refrigeration system consists of a generator, a condenser, an evaporator, and an absorber. The evaporator outlet is connected to a shell-and-tube heat exchanger. Low-pressure gaseous CO2, cooled by a circulating water cooler, is introduced into the tube side, while chilled water generated by the evaporator is introduced into the shell side. Through deep heat exchange, the low-pressure gaseous CO2 releases its latent heat of phase change and condenses into low-pressure liquid CO2. The low-pressure liquid CO2 flows back to the low-pressure CO2 liquid storage tank through pipelines, completing the entire process of CO2 cooling. The driving heat source for the lithium bromide refrigeration system is high-temperature hot water supplied by the chemical waste heat collection module. After releasing heat in the generator, the hot water cools down and flows back to the hot water heat exchanger to absorb heat again, realizing the recycling of waste heat.

[0029] In this embodiment, the dynamic heat transfer model in the first segment is: Q 回热 =k×A×ΔTlm, where k is the overall heat transfer coefficient, A is the effective heat transfer area, and ΔTlm is the logarithmic mean temperature difference, which is calculated as follows: ΔTlm=[(T 透出 -T2 出 )-(T1 出 -T 电泵出 )] / ln[(T 透出 -T2 出 ) / (T1 出 -T电泵出 )], where T1 出 and T2 出 These represent the CO2 temperatures at the outlets of the two ends of the regenerative heat exchanger, respectively; and the heat exchange efficiency η of the regenerative heat exchanger. 回热 The calculation method is as follows: , among which, T CO2热进 =T 透出 T represents the CO2 outlet temperature of the supercritical CO2 turbine. CO2冷进 =T 电泵出 , is the CO2 outlet temperature of the two-stage liquid-liquid compression pump, T CO2热出 =T2 出 , which is the CO2 temperature output from the shell side of the regenerative heat exchanger; the adaptive baffle adjustment algorithm uses a fuzzy PID controller, which outputs a baffle angle adjustment command with the set regenerative efficiency value as the target, and adjusts the baffle angle through a servo motor to ensure stable regenerative efficiency.

[0030] Specifically, when Q 透出 >90m 3 When an overload occurs, the baffle angle θ is increased to 35-45° to increase the turbulence intensity in the tube side, and k is increased by 10%-15% to avoid T. 透出 >35℃; when Q 透出 When the flow rate is <70 m³ / h, and low load conditions occur, the baffle angle θ is reduced to 15-25° to reduce tube resistance. Simultaneously, k is reduced by 5%-8% to avoid T... 电泵出 <42℃, to ensure the waste heat demand of the subsequent high-pressure heat exchanger.

[0031] In this embodiment, in the second segment, the dynamic cooling flow model is: Q 冷 =(Q3×ρ×cp×ΔT CO2 ) / (ρ 冷 ×cp 冷 ×ΔT 冷 ), ΔT CO2 ρ is the difference between the outlet CO2 temperature and the target temperature of the regenerative heat exchanger, where ρ is the CO2 density and cp is the specific heat capacity of gaseous CO2. 冷 For the density of circulating water, cp 冷 ΔT is the specific heat capacity of circulating water. 冷 Let ΔT be the temperature difference between the inlet and outlet of the circulating water cooler. 冷 =T 冷出 -T 冷进 The temperature is ≤10K to prevent the circulating water temperature from being too high and affecting subsequent cooling; the cooling efficiency η of the circulating water cooler is... 循冷 The calculation method is as follows: T CO2循进 and T CO2循出These are the inlet and outlet CO2 temperatures of the circulating water cooler, respectively, T. 冷进 The circulating water inlet temperature; the PID flow regulation algorithm uses Q... 冷 The calculated value is the target value. By adjusting the opening of the electric regulating valve in the cooling water pipeline, the actual flow rate of the circulating water is controlled, thereby reducing the power consumption of the circulating water pump.

[0032] Specifically, when T3 > 35℃, and an overheating condition occurs, the opening of the electric regulating valve in the cooling water pipeline increases to 80%-100%, Q 冷 Rise to 220-250m 3 / h; When T3 < 33℃, under low heat load conditions, the opening of the electric regulating valve in the cooling water pipeline is reduced to 50%-70%, Q 冷 Reduced to 154-198m 3 / h.

[0033] In this embodiment, in the third section, the coupling model between cooling capacity and waste heat demand is: Q 制 =(Q4 / 3600)×ρ 气态 ×r, Q 热 =Q 制 / (COP×ρ 热 ×cp 热 ×ΔT 热 ), ρ 气态 Let ρ be the density of gaseous CO2, r be the latent heat of CO2 phase change, COP be the coefficient of performance of lithium bromide, and ρ be the density of gaseous CO2. 热 To drive the density of hot water, cp 热 To drive the specific heat capacity of hot water, ΔT 热 To drive the hot water temperature difference; where the total CO2 cooling capacity Q 冷却总 The calculation method for Q is as follows: 冷却总 =G CO2 ×[c 气 ×(T 冷却段进 -T CO2饱 )+r+c 液 ×(T CO2饱 -T 冷却段出 )], G CO2 c is the CO2 mass flow rate. 气 T is the isobaric specific heat capacity of gaseous CO2. 冷却段进 and T 冷却段出 These are the CO2 temperatures at the inlet and outlet of the cooling section, respectively. 液 T is the isobaric specific heat capacity of liquid CO2. CO2饱 The CO2 saturation temperature is used; the fuzzy control algorithm uses fuzzy control to dynamically adjust the opening of the hot water regulating valve, thereby avoiding the waste of driving waste heat.

[0034] Specifically, when T4 > 22℃ and insufficient condensation occurs, the opening of the hot water regulating valve is increased to 80%-100%, Q 热 Increase to 250-300m 3 / h, COP maintained at 1.2-1.3; when T4 < 18℃, and over-condensation occurs, the opening of the hot water regulating valve is reduced to 50%-70%, Q 热 Reduced to 120-180m 3 / h, COP≥1.0, to avoid wasting drive waste heat.

[0035] The transcritical liquid-liquid compression CO2 energy storage module is used to compress low-pressure liquid CO2 obtained from the three-stage staged cooling module to high-pressure liquid. It uses a two-stage liquid-liquid compression electric pump as a booster device to directly compress the low-pressure liquid CO2. The compressed CO2 directly enters the shell side of the regenerating heat exchanger and performs countercurrent heat exchange with the gaseous CO2 from the outlet of the supercritical CO2 turbine entering the tube side of the regenerating heat exchanger. This achieves preheating of the high-pressure liquid CO2 and precooling of the low-pressure gaseous CO2, reducing the waste heat consumption of the subsequent high-pressure heat exchanger. The heat exchange tubes use irregularly shaped finned tubes, which can enhance the heat transfer coefficient. At the same time, a dual-parameter closed-loop control of temperature and pressure is set at the outlet of the high-pressure heat exchanger. The CO2 temperature is monitored in real time by a platinum resistance temperature sensor and the CO2 pressure is monitored in real time by a pressure transmitter. When the CO2 temperature or pressure deviates from the supercritical stability threshold, the system will automatically adjust the waste heat distribution valve group.

[0036] In this embodiment, the two-stage liquid-liquid compression pump adopts an asymmetric compression structure of one stage + two stages. The first stage compression chamber is used to adapt to liquid CO2 with a low compression coefficient, and the second stage compression chamber is used to adapt to liquid CO2 with a high compression coefficient. Compared with the proportional compression of traditional compressors, such as 1:1.41, the design of this invention reduces the irreversible loss in the compression process by 22%, and precisely matches the inlet temperature requirements of the subsequent regenerative heat exchanger, thus avoiding the interstage heat load imbalance caused by proportional compression.

[0037] In this embodiment, the two-stage liquid-liquid compression pump is equipped with a segmented jacketed cooling channel, dividing the pump jacket into two sections: the first-stage compression chamber corresponds to the low-flow-rate channel, and the second-stage compression chamber corresponds to the high-flow-rate channel; and the first-stage compression chamber corresponds to a 0.015m... 2 The flow channel is designed to accommodate flow velocities of 1.2-1.5 m / s, with a secondary compression chamber corresponding to 0.01 m. 2 The flow channel is adapted to flow velocities of 1.8-2.2 m / s. At the same time, it is linked with three sets of housing temperature sensors and independent electric regulating valves to dynamically match the 40% heat load difference between the two stages of the two-stage liquid-liquid compression pump, so that the pump operating temperature is stabilized at 45±2℃.

[0038] In this embodiment, a buffer chamber connected to a low-pressure liquid storage tank is set outside the mechanical seal of the two-stage liquid-liquid compression pump to reduce the pressure difference across the sealing surface. A leakage recovery circuit is also designed to return any small amount of leaked CO2 to the low-pressure CO2 liquid storage tank, thereby reducing the leakage rate of the mechanical seal. A Y-type high-efficiency filter and a pressure stabilizer are installed at the inlet of the two-stage liquid-liquid compression pump. The Y-type high-efficiency filter has a filtration accuracy of 8μm, and the pressure stabilizer has a built-in elastic diaphragm with a volume of 5L. This is used to control the CO2 pressure fluctuation at the outlet of the low-pressure liquid CO2 storage tank within ±0.1MPa, ensuring stable pump inlet pressure and avoiding flow pulsation caused by pressure fluctuations in existing hydraulic pumps.

[0039] In summary, this invention utilizes a dual-path dynamic allocation mechanism for waste heat acquisition in chemical reactors, enabling real-time linkage adjustment between waste heat demand and load conditions. This overcomes the limitations of traditional static waste heat allocation and improves waste heat utilization. The three-stage cooling module employs a three-stage intelligent cooling system with multi-parameter sensing, inter-stage linkage modeling, and adaptive algorithm adjustment capabilities. This achieves dynamic matching between CO2 cooling capacity and CO2 operating conditions, improving CO2 condensation efficiency and avoiding large fluctuations in condensation efficiency. The transcritical liquid-liquid compression CO2 energy storage module uses a two-stage non-uniform liquid-liquid compression electric pump as a booster, ensuring that liquid CO2 remains liquid throughout the pressurization process. This completely avoids latent heat loss due to phase change in traditional compressor systems, improving pump compression efficiency. Furthermore, the combination with a segmented jacketed intelligent cooling channel reduces mechanical seal leakage, demonstrating significant advancements in technology.

[0040] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, characterized in that, This includes a waste heat recovery module for chemical reactors, a three-stage staged cooling module, and a transcritical liquid-liquid compression CO2 energy storage module, among which: The waste heat acquisition module of the chemical reactor is used to provide a driving heat source for the hot water lithium bromide refrigeration subsystem and to supplement the heat for heating high-pressure liquid CO2 to the supercritical state. It adopts a dual-path dynamic distribution mechanism for waste heat, and designs a waste heat distribution valve group with both manual and electric control to dominate the waste heat distribution logic in energy storage mode and energy release mode. In energy storage mode, the waste heat of the chemical reactor is preferentially transferred to the high-pressure heat exchanger; in energy release mode, the waste heat of the chemical reactor is preferentially transferred to the hot water lithium bromide refrigeration subsystem. The three-stage staged cooling module utilizes waste heat from the waste heat collection module of the chemical reactor to condense gaseous CO2 into a low-pressure liquid state. It employs a three-stage intelligent cooling system with multi-parameter sensing, inter-stage linkage modeling, and adaptive algorithm adjustment capabilities. The first stage collects the CO2 flow rate Q at the outlet of the supercritical CO2 turbine. 透出 Temperature T 透出 and pressure P 透出 And the CO2 flow rate Q at the outlet of the two-stage liquid-liquid compression pump 电泵出 and temperature T 电泵出 Then, the regenerated heat Q of the regenerating heat exchanger is calculated based on the dynamic heat transfer model. 回热 Simultaneously, the baffle angle is dynamically adjusted using an adaptive baffle adjustment algorithm; the second stage first collects the CO2 outlet temperature T3 and flow rate Q3 of the regenerating heat exchanger, as well as the circulating water inlet and outlet temperatures T of the circulating water cooler. 冷进 and T 冷出 Then, the minimum circulating water flow rate Q required by the circulating water cooler is calculated based on the dynamic cooling flow rate model. 冷 Simultaneously, the circulating water flow rate of the circulating water cooler is adjusted in real time using a PID flow regulation algorithm; the third stage first collects the CO2 outlet temperature T4, flow rate Q4, and pressure P4 of the circulating water cooler, as well as the chilled water outlet temperature T of the hot water lithium bromide refrigeration subsystem. 冻 and driving hot water flow rate Q 热 Then, based on the coupled model of cooling capacity and waste heat demand, the cooling capacity Q required for the hot water lithium bromide refrigeration subsystem to condense CO2 is calculated. 制 and driving hot water flow rate Q 热 Meanwhile, the hot water flow rate is adjusted in real time using a fuzzy control algorithm; The transcritical liquid-liquid compression CO2 energy storage module is used to compress the low-pressure liquid CO2 obtained by the three-stage staged cooling module to a high-pressure liquid state. It uses a two-stage liquid-liquid compression electric pump as a booster device to directly compress the low-pressure liquid CO2. The compressed CO2 directly enters the shell side of the regenerator heat exchanger and exchanges heat with the gaseous CO2 at the outlet of the supercritical CO2 turbine in a countercurrent manner.

2. The staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 1, is characterized in that... Both the energy storage mode and the energy release mode are equipped with electromagnetic flow meters and platinum resistance temperature sensors in the waste heat distribution path. The electromagnetic flow meters and platinum resistance temperature sensors are used to obtain the waste heat flow rate and inlet temperature of the hot water lithium bromide refrigeration subsystem and the high-pressure heat exchanger in real time, respectively.

3. The staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 2, is characterized in that... In the energy release mode, when the waste heat flow and inlet temperature of the collected hot water lithium bromide refrigeration subsystem are lower than the threshold, the system's refrigeration priority compensation mechanism will be triggered; in the energy storage mode, when the waste heat flow and inlet temperature of the collected high-pressure heat exchanger are lower than the threshold, the system's energy storage priority compensation mechanism will be triggered.

4. The staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 1, is characterized in that... After meeting the minimum waste heat requirements in both energy storage and energy release modes, the remaining allocable waste heat resources ΔQ are allocated according to an allocation function. The allocation function for energy release mode is: Q1 = Q1_min + ΔQ × K1 × (COP) 实时 / COP 额定 The allocation function under the energy storage mode is: Q2 = Q2_min + ΔQ × K2 × (η) 换热实时 / η 换热额定 ), where Q1 and Q2 are the waste heat resources allocated to the two modes, Q1_min and Q2_min are the minimum waste heat requirements of the two modes, K1 and K2 are the mode weighting coefficients, and COP 实时 The current coefficient of performance (COP) for the hot water lithium bromide refrigeration subsystem. 额定 η is the rated coefficient of performance for a hot water lithium bromide refrigeration subsystem. 换热实时 η represents the current heat exchange efficiency of the high-pressure heat exchanger. 换热额定 This refers to the rated heat exchange efficiency of the high-pressure heat exchanger.

5. The staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 1, is characterized in that... In the first section, the dynamic heat transfer model is: Q 回热 =k×A×ΔTlm, where k is the overall heat transfer coefficient, A is the effective heat transfer area, and ΔTlm is the logarithmic mean temperature difference; The adaptive deflector adjustment algorithm uses a fuzzy PID controller to output a deflector angle adjustment command with the set regenerative efficiency value as the target, and adjusts the deflector angle through a servo motor.

6. The staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 1, is characterized in that... In the second section, the dynamic cooling flow model is: Q 冷 =(Q3×ρ×cp×ΔT CO2 ) / (ρ 冷 ×cp 冷 ×ΔT 冷 ), ΔT CO2 ρ is the difference between the outlet CO2 temperature and the target temperature of the regenerative heat exchanger, where ρ is the CO2 density and cp is the specific heat capacity of gaseous CO2. 冷 For the density of circulating water, cp 冷 ΔT is the specific heat capacity of circulating water. 冷 The circulating water temperature difference between the inlet and outlet of the circulating water cooler; the PID flow regulation algorithm uses Q... 冷 The calculated value is the target value, and the actual flow rate of the circulating water is controlled by adjusting the opening of the electric regulating valve in the cooling water pipeline.

7. The staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 1, is characterized in that... In the third paragraph, the coupling model between cooling capacity and waste heat demand is: Q 制 =(Q4 / 3600)×ρ 气态 ×r, Q 热 =Q 制 / (COP×ρ 热 ×cp 热 ×ΔT 热 ), ρ 气态 Let ρ be the density of gaseous CO2, r be the latent heat of phase change, COP be the coefficient of performance of lithium bromide, and ρ be the density of gaseous CO2. 热 To drive the density of hot water, cp 热 To drive the specific heat capacity of hot water, ΔT 热 To drive the hot water temperature difference, the fuzzy control algorithm uses fuzzy control to dynamically adjust the opening of the hot water regulating valve.

8. The staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 1, is characterized in that... The two-stage liquid-liquid compression pump adopts an asymmetric compression structure of one stage + two stages. The first stage compression chamber is used to adapt to liquid CO2 with a low compressibility coefficient, and the second stage compression chamber is used to adapt to liquid CO2 with a high compressibility coefficient.

9. A staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 8, is characterized in that... The two-stage liquid-liquid compression pump is equipped with a segmented jacketed cooling channel, which divides the pump jacket into two sections: the first-stage compression chamber corresponds to the low-flow-rate channel, and the second-stage compression chamber corresponds to the high-flow-rate channel.

10. A staged cooling compressed CO2 energy storage and power generation system coupled with waste heat from chemical industry, as described in claim 1, is characterized in that... A buffer chamber connected to a low-pressure liquid storage tank is provided outside the mechanical seal of the two-stage liquid-liquid compression pump to reduce the pressure difference on both sides of the sealing surface.

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