A method and system for utilizing waste heat from chemical plants across multiple lifecycles, comprising multi-layer energy storage units.

Abstract

This invention discloses a method and system for cross-cycle waste heat utilization in chemical industries, comprising multi-layer energy storage units. The method includes: acquiring flow parameters of a chemical system in multiple single cycles; formulating energy targets and energy consumption requirements for the chemical system based on these parameters; calculating the heat exchange network structure of the chemical system within each single cycle based on the energy targets and energy consumption requirements; integrating the heat exchange network structure and energy targets within each single cycle; and designing the installation locations of the multi-layer energy storage units in the chemical system based on the integrated heat exchange network structure and energy targets to achieve cross-cycle waste heat energy recovery and utilization. This invention solves the problem of existing technologies' inefficient utilization of chemical waste heat from different cycles, leading to significant heat energy waste and low energy utilization efficiency in chemical systems.

Description

Technical Field

[0001] This invention relates to the field of chemical production technology, and in particular to a method and system for utilizing waste heat from chemical processes across multiple cycles, comprising a multi-layer energy storage unit. Background Technology

[0002] With the rapid development of modern life and industrial production, energy and environmental issues have become hot topics of global concern in recent years. Chemical systems, as typical energy-intensive industries, involve a large amount of heat exchange and energy consumption, leading to significant energy pollution problems.

[0003] To reduce energy consumption and pollution from chemical production, chemical systems typically require the matching and conversion of hot and cold fluids to improve energy efficiency. Specifically, in chemical production, to meet specific process requirements, the working fluid usually needs to be heated or cooled to a specific temperature before production, resulting in chemical systems containing a large amount of both high-temperature and low-temperature fluids. Through heat exchange network design, chemical systems can use high-temperature fluids to heat low-temperature fluids, and vice versa; by matching and exchanging hot and cold fluids, the target fluid temperature can be achieved while also utilizing waste heat from chemical processes, thus reducing carbon emissions.

[0004] The matching and heat exchange of hot and cold streams in chemical systems heavily rely on heat exchange network design. Traditional heat exchange network research typically focuses on energy optimization of the production process in a single cycle. However, in actual production processes, the temperature, flow rate, and physical properties of each stream in a chemical system are all variable, and the heating or cooling energy required for each stream also changes over time. This results in the energy supply and demand changes of each stream in a chemical system not being periodic. Optimizing a single-cycle heat exchange network alone is insufficient to solve these problems, making it difficult to efficiently utilize waste heat from different times and cycles in the chemical system. This leads to a significant waste of heat in the chemical system and low energy utilization efficiency. Summary of the Invention

[0005] This invention provides a cross-cycle chemical waste heat utilization scheme including multi-layer energy storage units, aiming to solve the problem that the existing single-cycle heat exchange network optimization scheme is difficult to efficiently utilize chemical waste heat at different times and cycles, resulting in a large amount of heat waste and low energy utilization efficiency in the chemical system.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a method for utilizing waste heat from chemical processes across multiple cycles, comprising a multi-layered energy storage unit, is proposed, including:

[0007] Obtain the flow parameters of the chemical system in multiple single cycles;

[0008] Based on the flow parameters of the chemical system in multiple single cycles, formulate the energy target and energy consumption requirements of the chemical system;

[0009] The heat exchange network structure of the chemical system within each single cycle is calculated based on the energy target and energy consumption demand of the chemical system within each single cycle.

[0010] The heat exchange network structure and energy target of multiple single-cycle chemical systems are integrated, and the installation position of multi-layer energy storage units in the chemical system is designed based on the integrated heat exchange network structure and energy target to carry out cross-cycle waste heat energy recovery and utilization.

[0011] Preferably, in the above-mentioned method for utilizing waste heat from chemical plants across multiple cycles, the step of formulating the energy target and energy consumption demand of the chemical system based on the flow parameters of the chemical system in multiple single cycles includes:

[0012] Based on the flow parameters of the chemical system in multiple single cycles, the energy composite curve corresponding to each single cycle is plotted, and the pinch temperature of the heat exchange network in each single cycle is obtained from the energy composite curve.

[0013] Calculate the utility usage for each single-cycle chemical system based on the energy composite curve;

[0014] By integrating the pinch temperature and utility usage for each single cycle, a multi-pinch temperature distribution map and the maximum and minimum utility usage within a single cycle are obtained.

[0015] Preferably, in the above-mentioned method for utilizing waste heat from a multi-cycle chemical plant, the step of calculating the heat exchange network structure of the chemical system within a single cycle, based on the energy target and energy consumption demand of the chemical system within each single cycle, includes:

[0016] Based on the slope of the energy composite curve corresponding to the hot and cold flow streams, the energy composite curves corresponding to multiple single cycles are divided into multiple blocks;

[0017] Based on the block parameters of each block in multiple blocks, heat exchange network modeling and integration are performed for each block to obtain the heat exchange network structure of the chemical system.

[0018] Based on the maximum and minimum utility usage within a single cycle, calculate the installation location and usage of the utilities required for the heat exchange network structure in each single cycle.

[0019] Preferably, in the above-mentioned method for utilizing waste heat in a multi-cycle chemical plant, the step of designing the installation location of the multi-layer energy storage unit in the chemical system based on the heat exchange network structure and energy target includes:

[0020] Based on the heat exchange network structure and the installation location and quantity of the utilities required by the heat exchange network, determine the energy difference in each block of the heat exchange network within each single cycle;

[0021] Based on the energy difference in each block of the heat exchange network within each single cycle, data modeling of the heat exchange network is performed to obtain the installation location of the multi-layer energy storage unit.

[0022] Preferably, the above-mentioned method for utilizing waste heat from chemical plants across cycles further includes, after the step of designing the installation location of the multi-layer energy storage unit in the chemical system based on the integrated heat exchange network structure 5 and the energy target:

[0023] Based on the block parameters of each block in multiple blocks, determine whether the heat exchange possibility of the utility in each single cycle meets the minimum heat transfer temperature difference.

[0024] If the heat exchange capability of the utility meets the minimum heat transfer temperature difference, then based on the heat exchange network in each block

[0025] The existing energy difference information is used to control the energy storage units at the corresponding installation locations to utilize the charge and discharge heat across cycles. Preferably, the above-mentioned cross-cycle chemical waste heat utilization method, after the step of designing the installation locations of multi-layer energy storage units in the chemical system based on the integrated heat exchange network structure and energy target, further includes:

[0026] Determine whether a multi-layer energy storage unit meets economic requirements based on its installation location, size, and cost.

[0027] If the multi-layer energy storage unit meets the economic requirements, then the heat exchange network structure containing the multi-layer energy storage unit is acquired and displayed.

[0028] According to a second aspect of the present invention, the present invention also provides a cross-cycle chemical waste heat utilization system comprising a multi-layer energy storage unit, comprising:

[0029] The parameter acquisition module is used to acquire the flow parameters of the chemical system in multiple single cycles;

[0030] The demand formulation module is used to formulate the energy target and energy consumption demand of the chemical system based on the flow parameters of the chemical system in multiple single cycles.

[0031] The structural calculation module is used to calculate the heat exchange network structure of the chemical system within a single cycle based on the energy target and energy consumption demand of the chemical system within each single cycle.

[0032] The location design module is used to integrate the heat exchange network structure and energy of multiple single-cycle chemical systems.

[0033] The goal is to design the installation location of the multi-layer energy storage unit 5 in the chemical system based on the integrated heat exchange network structure and energy target, so as to carry out cross-cycle waste heat energy recovery and utilization.

[0034] Preferably, in the above-mentioned cross-cycle chemical waste heat utilization system, the demand formulation module includes:

[0035] The curve plotting submodule is used to plot the energy composite curve for each single cycle based on the flow parameters of the chemical system in multiple single cycles.

[0036] The temperature acquisition submodule is used to obtain the pinch zero temperature of each single-cycle heat exchanger network from the energy composite curve;

[0037] The usage calculation submodule is used to calculate the utility usage of each single-cycle chemical system based on the energy composite curve.

[0038] The data integration submodule is used to integrate the pinch temperature and utility usage for each single cycle to obtain a multi-pinch temperature distribution map and the maximum and minimum utility usage within a single cycle.

[0039] Preferably, in the above-mentioned cross-cycle chemical waste heat utilization system, the structural calculation module includes:

[0040] The curve division submodule is used to divide the energy composite curves corresponding to multiple single cycles into multiple blocks based on the slope of the energy composite curves corresponding to the cold and hot flow streams.

[0041] The modeling and integration submodule is used to model and integrate the heat exchange network of each block according to the block parameters of each block in multiple blocks, so as to obtain the heat exchange network structure of the chemical system.

[0042] The engineering calculation submodule is used to calculate the installation location and quantity of utilities required for the heat exchange network structure in each single cycle, based on the maximum and minimum utility usage within a single cycle.

[0043] Preferably, in the above-mentioned cross-cycle chemical waste heat utilization system, the location design module includes:

[0044] The energy difference calculation submodule is used to determine the energy difference of the heat exchange network in each block within each single cycle, based on the heat exchange network structure and the installation location and quantity of the utilities required by the heat exchange network.

[0045] The data modeling submodule is used to perform data modeling on the heat exchange network based on the energy difference in each block of the heat exchange network within each single cycle, thereby obtaining the installation location of the multi-layer energy storage unit.

[0046] In summary, the cross-cycle chemical waste heat utilization scheme comprising multi-layer energy storage units provided by this invention obtains the flow parameters of the chemical system in multiple single cycles, and then formulates the energy target and energy consumption demand of the chemical system based on these parameters. Based on the energy target and energy consumption demand of the chemical system in each single cycle, a heat exchange network structure for the chemical system within that single cycle is designed. By integrating the heat exchange network structure and energy target of the chemical system in different single cycles, the installation positions of the multi-layer energy storage units within the heat exchange network structure can be designed based on the integrated structure. This allows the multi-layer energy storage units to regulate the hot and cold flow streams in the heat exchange network structure across cycles, achieving waste heat recovery and utilization in different cycles. This eliminates the need for additional heat exchangers to achieve temperature rise and fall of the hot and cold flow streams, thus solving the problems of significant heat energy waste and low energy utilization efficiency in existing chemical systems. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the structure of a chemical system with different cycles provided in an embodiment of the present invention;

[0049] Figure 2 This is a schematic diagram of a chemical system including a multi-layer energy storage unit provided in an embodiment of the present invention;

[0050] Figure 3 This is a schematic flowchart of the first method for utilizing waste heat from chemical plants across multiple cycles, which includes a multi-layer energy storage unit, provided by an embodiment of the present invention.

[0051] Figure 4 yes Figure 3 The illustrated embodiment provides a flowchart of a method for determining energy targets and energy consumption requirements for a chemical system.

[0052] Figure 5 yes Figure 3 The illustrated embodiment provides a flowchart of a calculation method for a heat exchanger network structure;

[0053] Figure 6 yes Figure 3 The illustrated embodiment provides a flowchart of a method for designing the installation location of a multi-layer energy storage unit.

[0054] Figure 7 This is a schematic flowchart of the second method for utilizing waste heat from chemical plants across multiple cycles, which includes a multi-layer energy storage unit, provided in an embodiment of the present invention.

[0055] Figure 8 This is a schematic diagram of a cross-cycle chemical waste heat utilization system including multi-layer energy storage units provided in an embodiment of the present invention;

[0056] Figure 9 yes Figure 8 The illustrated embodiment provides a structural diagram of a requirements formulation module;

[0057] Figure 10 yes Figure 8 The illustrated embodiment provides a structural diagram of a structural calculation module;

[0058] Figure 11 yes Figure 8 The illustrated embodiment provides a structural schematic diagram of a position design module.

[0059] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0060] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0061] The main technical problem solved by the embodiments of the present invention is:

[0062] The matching and heat exchange of hot and cold streams in chemical systems heavily rely on heat exchange network design. Traditional heat exchange network research typically focuses on energy optimization of the production process in a single cycle. However, in actual production processes, the temperature, flow rate, and physical properties of each stream in a chemical system are all variable, and the heating or cooling energy required for each stream also changes over time. This results in the energy supply and demand changes of each stream in a chemical system not being periodic. Optimizing a single-cycle heat exchange network alone is insufficient to solve these problems, making it difficult to efficiently utilize waste heat from different times and cycles in the chemical system. This leads to a significant waste of heat in the chemical system and low energy utilization efficiency.

[0063] like Figure 1 As shown, a chemical system includes two different heat exchange network structure design schemes under operating cycle A and operating cycle B;

[0064] The chemical system under operating cycles A and B includes process heat exchangers 1, 2, 3, 4, and 5; hot flow pipelines 6, 7, 8, and 9; utility heat exchangers 10, 11, and 12; cold utility 13; and hot utility 14.

[0065] Hot flow streams operate in hot flow stream lines 6 and 7 respectively. The streams contain production materials in the chemical system, and their initial temperature is higher than the target temperature. The temperature of the streams needs to be cooled in the chemical process to meet production requirements.

[0066] Cold flow streams operate in cold flow stream lines 8 and 9 respectively. The flow streams contain production materials in the chemical system, and their initial temperature is lower than the target temperature. The flow stream temperature needs to be heated in the chemical process to meet production requirements.

[0067] The thermal utility 14 is an external heat source independent of the cold and hot flow streams. If the cold flow stream fails to reach the required target temperature after heat exchange with the hot flow stream, it can be further heated to the target temperature through the thermal utility. Common thermal utilities include hot water and steam; however, installing thermal utility 14 is costly.

[0068] Cooling utility 13 is an external heat source independent of the hot and cold flow streams. If the hot flow stream fails to reach the required target temperature after heat exchange with the cold flow stream, it can continue to cool to the target temperature through the cooling utility. Common cooling utilities include chilled water and air, which are relatively inexpensive.

[0069] The aforementioned process heat exchangers 1, 2, 3, 4, and 5 are used to connect the cold and hot flow pipelines, enabling energy exchange between the cold and hot flow streams within the chemical process system and fully or partially meeting the temperature targets of the cold and hot flow streams. For example, during operating cycle A, process heat exchanger 1 connects the hot flow stream 6 and the cold flow stream 8, using the heat from the hot flow stream 6 to heat the cold flow stream 8. The process heat exchanger can simultaneously lower the temperature of the hot flow stream 6 and raise the temperature of the cold flow stream 8, thus realizing the utilization of waste heat within the chemical system.

[0070] Common utility heat exchangers 10, 11, and 12 can be used to connect cold flow pipes to hot utility 14, or hot flow pipes to cold utility 13, fully meeting the temperature targets of the cold and hot flow pipes. For example, during operating cycle A, after cold flow pipe 8 exchanges heat with hot flow pipe 6 through process heat exchanger 1, its flow temperature has not yet reached the target temperature. Therefore, it needs to be further heated to the target temperature through hot utility 14 to meet process requirements. At this time, common utility heat exchanger 11 is needed to connect cold flow pipe 8 and hot utility 14 to achieve heat exchange between the cold and hot flow pipes. As another example, during operating cycle B, hot flow pipe 7 exchanges heat with cold flow pipe 9 through process heat exchanger 3, and with cold flow pipe 8 through process heat exchanger 4. This process can lower the temperature of hot flow pipe 7 while raising the temperatures of cold flow pipes 8 and 9. However, the temperature of the hot flow pipe 7 after heat exchange has not yet reached the target temperature, so further cooling is required to meet the process requirements. At this time, the utility heat exchanger 10 is needed to connect the hot flow pipe 7 and the cold utility 13 to achieve heat exchange and reduce the temperature of the hot flow pipe 7 to the target temperature.

[0071] As can be seen from the above implementation scheme, within the same operating cycle, waste heat utilization within the system can be achieved through matching hot and cold streams, reducing the amount of utility usage, thereby improving energy efficiency and reducing operating costs. However, in the actual operation of chemical systems, there are often fluctuating heating and cooling demands. For example, in operating cycle A, hot stream 7 does not participate in any heat exchange with cold streams. Therefore, in order to cool hot stream 7 to the target temperature, a large amount of cold utility 13 is required for cooling hot stream 7, resulting in energy waste and increased operating costs. In operating cycle B, hot stream 7 exchanges heat with cold streams 8 and 9 respectively. Thus, it can be seen that the required amount of cold utility 13 is smaller in operating cycle B, and the overall system energy efficiency is higher, but it will lead to excessive energy consumption and energy waste.

[0072] To address the aforementioned issues and further improve energy efficiency, a multi-layered energy storage unit is added between cycle A and cycle B to enable cross-cycle utilization of waste heat from chemical processing. See details... Figure 2 , Figure 2 This is a structural diagram of a heat exchange network that includes two operating cycles and multiple layers of energy storage units. (See diagram for example.) Figure 2 As shown, the multi-cycle chemical waste heat utilization system includes: multi-layer energy storage unit 15, energy charging pipeline 19 and energy releasing pipeline 20.

[0073] The multi-layer energy storage unit 15 includes multiple layers of energy storage materials 16. Each layer of energy storage material 16 is independent and connected in series. An electric valve 17 in an open state and an electric valve 18 in a closed state are installed between each layer of energy storage material 16. By opening and closing the electric valves 17 and 18, the participation of each layer of energy storage material in heat storage and release can be controlled. Furthermore, the heat storage capacity of the energy storage unit can be adjusted by the electric valves according to the different energy storage requirements corresponding to each cycle. The heat from the hot flow stream 7 during operating cycle A is stored in the multi-layer energy storage unit 15 through the charging pipeline 19, completely eliminating or reducing the consumption of the cold utility 13 while meeting the target temperature of the hot flow stream 7. When the system operates into operating cycle B, heat is released to the cold flow streams 8 and 9 through the energy release pipeline 20, completely eliminating or reducing the consumption of the thermal utility 14 while meeting the target temperatures of the cold flow streams 8 and 9, thereby achieving efficient utilization of waste heat energy.

[0074] The operation of the multi-layer energy storage unit 15 is as follows: An open electric valve 17 and a closed electric valve 18 are installed between the multiple layers of energy storage materials 16 to control the amount of energy storage material participating in the energy storage reaction, thereby controlling the stored energy. When the electric valve 17 is open, the energy storage material 16 in this layer participates in the energy storage reaction; when the electric valve 18 is closed, the energy storage material 16 in this layer does not participate in the energy storage reaction. Therefore, by setting up only one energy storage unit, the energy storage requirements for different cycles can be met, and waste heat can be recovered and utilized. This further eliminates the need for multiple utility heat exchangers, reduces energy consumption in the chemical system, and improves energy efficiency.

[0075] To implement the functions of the above system, please refer to the following: Figure 3 , Figure 3 This is a schematic flowchart illustrating a first method for utilizing waste heat from chemical plants across multiple cycles, incorporating a multi-layer energy storage unit, according to an embodiment of the present invention. This method is used for... Figure 2 The chemical system shown. For example... Figure 3 As shown, this cross-cycle chemical waste heat utilization system includes:

[0076] S110: Obtain the flow parameters of the chemical system in multiple single cycles. In this embodiment, the material flow data within the chemical system can be determined with a single cycle time of one hour. Considering the volatility of material flow data under actual operating conditions, this application takes the average value within one hour as the data corresponding to that cycle. The data to be obtained includes: initial temperature, target temperature, specific heat capacity, and flow rate of each flow stream.

[0077] S120: Based on the flow parameters of the chemical system in multiple single cycles, formulate the energy target and energy consumption requirements of the chemical system. By obtaining the flow parameters of multiple single cycles, it is possible to determine whether each cycle requires heat absorption and cooling or heat release and cooling, thereby obtaining the energy target and energy consumption requirements of the chemical system under different cycles through quantitative calculations. Specifically, based on the energy composite curve of the flow data of the chemical system under multiple cycles, the pinch point temperature in the heat exchange network of each cycle can be determined and the required utility consumption of the chemical system can be calculated, thus obtaining a multi-pinch point temperature distribution map and the maximum and minimum utility consumption required for each cycle.

[0078] S130: Based on the energy target and energy consumption requirements of the chemical system within each single cycle, the heat exchange network structure of the chemical system within that single cycle is calculated. After obtaining the energy target and energy consumption requirements of the chemical system within each single cycle, the chemical system needs to be divided into blocks, and the heat exchange network structure corresponding to each single cycle of the chemical system needs to be calculated. The division of the blocks is based on the slope of the composite curve of the hot and cold flows. Then, based on parameters such as the boundary enthalpy value and the hot and cold end temperature values ​​of the blocks, the heat exchange network model of each block is established and calculated to obtain the overall heat exchange network model, thereby obtaining the overall design of the heat exchange network.

[0079] S140: Integrates the heat exchange network structure and energy target of multiple single-cycle chemical systems, and designs the installation position of multi-layer energy storage units in the chemical system based on the integrated heat exchange network structure and energy target, so as to carry out cross-cycle waste heat energy recovery and utilization.

[0080] After obtaining the heat exchange network structure and energy target of each single-cycle chemical system, the heat exchange network structure and energy target corresponding to the above multiple single cycles are integrated. Then, based on the integrated heat exchange network structure and energy target, the installation position of the multi-layer energy storage unit in the chemical system is designed. In this way, by using the above multi-layer energy storage unit to exchange hot and cold energy for the chemical system in different cycles, the waste heat energy recovery and utilization across cycles can be realized.

[0081] In summary, the cross-cycle chemical waste heat utilization method including multi-layer energy storage units provided by the above embodiments of the present invention obtains the flow parameters of the chemical system in multiple single cycles, and then formulates the energy target and energy consumption demand of the chemical system based on the flow parameters of these multiple single cycles. Based on the energy target and energy consumption demand of the chemical system in each single cycle, the heat exchange network structure of the chemical system in that single cycle is designed. By integrating the heat exchange network structure and energy target of the chemical system in different single cycles, the installation position of the multi-layer energy storage unit in the heat exchange network structure of the chemical system can be designed according to the integrated heat exchange network structure and energy target. Thus, the multi-layer energy storage unit is used to regulate the hot and cold flow streams in the heat exchange network structure across cycles, realizing the recovery and utilization of chemical waste heat in different cycles. It does not require the setting of additional heat exchangers to achieve the heating and cooling of hot and cold flow streams, thereby solving the problems of large amounts of heat energy waste and low energy utilization efficiency in existing chemical systems.

[0082] In one preferred embodiment, such as Figure 4 As shown, in the above-mentioned cross-cycle chemical waste heat utilization method, step S120: the step of formulating the energy target and energy consumption demand of the chemical system based on the flow parameters of the chemical system in multiple single cycles includes:

[0083] S121: Based on the flow parameters of the chemical system in multiple single cycles, plot the energy composite curve corresponding to each single cycle, and obtain the pinch temperature of the heat exchange network in each single cycle from the energy composite curve.

[0084] S122: Calculate the utility usage for each single-cycle chemical system based on the energy composite curve.

[0085] S123: Integrate the pinch temperature and utility usage for each single cycle to obtain a multi-pinch temperature distribution map and the maximum and minimum utility usage within a single cycle.

[0086] In the technical solution provided in this application embodiment, the heat absorption and release requirements of the chemical system in each single cycle are determined based on the flow parameters of the chemical system in multiple single cycles, including the initial temperature, target temperature, specific heat capacity, and flow rate of each flow stream. This allows for the plotting of the energy composite curve corresponding to each single cycle, and the determination of the pinch point temperature in the heat exchange network for each single cycle. Based on the aforementioned energy composite curve, the utility consumption of the chemical system in each single cycle can be calculated. Figure 1It can be seen that the utility usage is used to supplement the energy demand of the hot and cold flow streams. Thus, after calculating the utility usage (including the usage of external heat sources and external cold sources), it is possible to combine the above-mentioned pinch point temperatures to calculate the multi-pinch temperature distribution map and the maximum and minimum utility usage in a single cycle. Then, the overall heat exchange network structure of the chemical system can be calculated, and the multi-layer energy storage unit can be set in the optimal position of the heat exchange network structure to provide energy for the heat exchange network in different cycles.

[0087] In one preferred embodiment, such as Figure 5 As shown, in the above-mentioned cross-cycle chemical waste heat utilization method, step S130: based on the energy target and energy consumption demand of the chemical system in each single cycle, the heat exchange network structure of the chemical system in a single cycle is calculated, including:

[0088] S131: Based on the slope of the energy composite curves corresponding to the cold and hot flow streams, the energy composite curves corresponding to multiple single cycles are divided into multiple blocks. Among them, the block division is based on the slope of the cold and hot flow composite curves, and composite curves with similar slopes are merged into one block.

[0089] S132: Based on the block parameters of each block in multiple zones, heat transfer network modeling and integration are performed for each block to obtain the heat transfer network structure of the chemical system. The aforementioned block parameters include the boundary enthalpy and hot / cold end temperatures of the blocks. In this way, based on the fundamental principles of heat transfer, heat transfer network modeling and calculation can be performed on each block of the chemical system to obtain a hybrid integer nonlinear superstructure heat transfer network model, thus achieving the overall design of the heat transfer network structure.

[0090] S133: Based on the maximum and minimum utility usage within a single cycle, calculate the installation location and usage of the utilities required for the heat exchange network structure in each single cycle.

[0091] The technical solution provided in this application divides the energy composite curves corresponding to multiple single cycles into multiple blocks based on the slope of the energy composite curves corresponding to the cold and hot flows. Then, based on the block parameters of each block, heat exchange network modeling and integration are performed on each block to obtain the decoupled heat exchange network of the chemical system. The block division is based on the slope of the cold and hot flow composite curves, merging composite curves with similar slopes into one block. Block parameters include the boundary enthalpy and cold / hot end temperatures of each block. Based on the basic principles of heat transfer, heat exchange network modeling and calculation can be performed on each block of the chemical system, constructing a mixed-integer nonlinear superstructure heat exchange network model. The heat exchange network structures designed for each block are combined to obtain the overall heat exchange network design. Thus, after obtaining the overall heat exchange network design, the installation location and quantity of the required cold and hot utilities for each single cycle can be determined. Figure 1As shown, the heating and cooling utilities are used to absorb or release heat for the heating and cooling flow lines. After obtaining the installation location and usage of the heating and cooling utilities, the location and usage of the multi-layer energy storage units can be set according to the above installation location and usage.

[0092] In one preferred embodiment, such as Figure 6 As shown in the embodiment of this application, in the method for utilizing waste heat in a multi-cycle chemical industry, step S140 involves designing the installation location of a multi-layer energy storage unit in the chemical system based on the integrated heat exchange network structure and energy target, including:

[0093] S141: Based on the heat exchange network structure and the installation location and quantity of the utilities required by the heat exchange network, determine the energy difference in each block of the heat exchange network within each single cycle;

[0094] S142: Based on the energy difference of the heat exchange network in each block within each single cycle, data modeling is performed on the heat exchange network to obtain the installation location of the multi-layer energy storage unit.

[0095] In the technical solution provided in this application embodiment, the information on the overall design and utilities of the heat exchange network for each cycle obtained through the above steps can determine the energy difference in each block of the heat exchange network for different cycles; then, based on the operating cycle of the chemical system, the heat exchange network blocks and the energy difference information, the installation location of the multi-layer energy storage unit is determined through mathematical modeling to realize the recovery and utilization of waste heat energy across cycles.

[0096] Specifically, as a preferred embodiment, such as Figure 7 As shown, the above-mentioned method for utilizing waste heat in a multi-cycle chemical industry further includes, after step S140: designing the installation location of the multi-layer energy storage unit in the chemical system:

[0097] S150: Based on the block parameters of each block in multiple blocks, determine whether the heat exchange possibility of the utility in each single cycle meets the minimum heat transfer temperature difference.

[0098] S160: If the heat exchange capability of the utility meets the minimum heat transfer temperature difference, then based on the energy difference information of the heat exchange network in each block, control the energy storage unit at the corresponding installation location to perform cross-cycle heat charging and discharging utilization.

[0099] In this embodiment, the block parameters of each of the multiple blocks, including enthalpy difference and temperature range, are used to determine the possibility of direct heat exchange for utilities. When the minimum heat transfer temperature difference is met, the additional waste heat resources in the previous operating cycle are used to charge the energy storage unit, which also reduces the amount of cold utilities used in that cycle. In addition, the charged energy storage unit releases heat to the heat exchange network in the subsequent operating cycle, replacing the original required hot utilities, further improving the waste heat utilization rate and reducing operating costs.

[0100] In addition, as a preferred embodiment, such as Figure 7 As shown, the above-mentioned method for utilizing waste heat in a multi-cycle chemical system further includes, after the step of designing the installation location of the multi-layer energy storage unit in the chemical system:

[0101] S170: Determine whether the multi-layer energy storage unit meets the economic requirements based on the installation location, size, and cost of the energy storage unit;

[0102] S180: If the multi-layer energy storage unit meets the economic requirements, then obtain and display the heat exchange network structure containing the multi-layer energy storage unit.

[0103] The technical solution provided in this application determines whether a multi-layer energy storage unit meets economic requirements based on the installation location, size, and cost of the energy storage unit. Once it is determined that the economic requirements are met, a heat exchange network design scheme including the energy storage unit can be obtained.

[0104] Each of the aforementioned energy storage units comprises multiple layers of energy storage materials, connected in series. Electric valves are installed between the layers, allowing control over the heat storage and release activities of each layer. Furthermore, the amount of heat stored in each unit can be adjusted via the electric valves according to the different energy storage requirements of each cycle.

[0105] In addition, based on the same concept of the above method embodiments, the present invention also provides a cross-cycle chemical waste heat utilization system including multi-layer energy storage units to implement the above method of the present invention. Since the principle and method of solving the problem in this system embodiment are similar, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0106] See also: Figure 8 , Figure 8 This is a schematic diagram of a multi-cycle chemical waste heat utilization system comprising a multi-layer energy storage unit, provided as an embodiment of the present invention. Figure 8 As shown, this cross-cycle chemical waste heat utilization system is used for Figure 2The chemical system shown includes cold flow pipelines 8 and 9, and hot flow pipelines 6 and 7; process heat exchangers (1-5) connecting the cold flow pipelines and the hot flow pipelines; a thermal utility 14 connected to the cold flow pipelines, the thermal utility 14 housing heat exchangers 11 and 12; a cold utility 13 connected to the hot flow pipelines, the cold utility housing a cold utility heat exchanger 10; and a multi-layer energy storage unit 15 connecting the cold utility 13 and the hot utility 14. The multi-layer energy storage unit 15 comprises multiple layers of energy storage materials 16, each layer of energy storage materials being independent and connected in series. An open electric valve 17 and a closed electric valve 18 are installed between each layer of energy storage materials, allowing control over the participation of each layer of energy storage materials in heat storage and release. Furthermore, the heat storage capacity of the energy storage unit 15 can be adjusted via the electric valves according to different energy storage requirements in each cycle. The heat from the heat flow stream 7 during operating cycle A is stored in the multi-layer energy storage unit 15 through the energy charging pipeline 19, thereby completely eliminating or reducing the consumption of the cold utility 13 while meeting the target temperature of the heat flow stream 7. When the system operates to operating cycle B, heat is released to the cold flow streams 8 and 9 through the energy release pipeline 20, thereby completely eliminating or reducing the consumption of the heat utility 14 while meeting the target temperature of the cold flow streams 8 and 9, thus achieving efficient utilization of waste heat energy.

[0107] like Figure 8 As shown, the above-mentioned multi-cycle chemical waste heat utilization system including multi-layer energy storage units includes:

[0108] The parameter acquisition module 110 is used to acquire the flow parameters of the chemical system in multiple single cycles;

[0109] The demand formulation module 120 is used to formulate the energy target and energy consumption demand of the chemical system based on the flow parameters of the chemical system in multiple single cycles.

[0110] The structural calculation module 130 is used to calculate the heat exchange network structure of the chemical system in a single cycle based on the energy target and energy consumption demand of the chemical system in each single cycle.

[0111] The location design module 140 is used to integrate the heat exchange network structure and energy target of the above-mentioned multiple single-cycle chemical systems, and to design the installation location of the multi-layer energy storage unit in the chemical system based on the integrated heat exchange network structure and energy target, so as to carry out cross-cycle waste heat energy recovery and utilization.

[0112] As a preferred embodiment, such as Figure 9 As shown, in the above-mentioned cross-cycle chemical waste heat utilization system, the demand formulation module 120 includes:

[0113] The curve plotting submodule 121 is used to plot the energy composite curve corresponding to each single cycle based on the flow parameters of the chemical system in multiple single cycles.

[0114] Temperature acquisition submodule 122 is used to acquire the pinch temperature of each single-cycle heat exchanger network from the energy composite curve;

[0115] The usage calculation submodule 123 is used to calculate the utility usage of each single-cycle chemical system based on the energy composite curve.

[0116] The data integration submodule 124 is used to integrate the pinch temperature and utility usage for each single cycle to obtain a multi-pinch temperature distribution map and the maximum and minimum utility usage within a single cycle.

[0117] In addition, as a preferred embodiment, such as Figure 10 In the aforementioned cross-cycle chemical waste heat utilization system, the structural calculation module 130 includes:

[0118] The curve division submodule 131 is used to divide the energy composite curves corresponding to multiple single cycles into multiple blocks according to the slope of the energy composite curves corresponding to the cold and hot flow streams.

[0119] The modeling and integration submodule 132 is used to model and integrate the heat exchange network of each block according to the block parameters of each block in multiple blocks, so as to obtain the heat exchange network structure of the chemical system.

[0120] The engineering calculation submodule 133 is used to calculate the installation location and quantity of utilities required for the heat exchange network structure in each single cycle based on the maximum and minimum utility usage within a single cycle.

[0121] In addition, as a preferred embodiment, such as Figure 11 As shown, in the above-mentioned cross-cycle chemical waste heat utilization system, the location design module 140 includes:

[0122] The energy difference calculation submodule 141 is used to determine the energy difference of the heat exchange network in each block within each single cycle, based on the heat exchange network structure and the installation location and quantity of the utilities required by the heat exchange network.

[0123] The data modeling submodule 142 is used to perform data modeling on the heat exchange network based on the energy difference in each block of the heat exchange network within each single cycle, so as to obtain the installation location of the multi-layer energy storage unit.

[0124] In summary, the multi-cycle chemical waste heat recovery system with multi-layer energy storage units provided by the above embodiments of the present invention obtains the flow parameters of the chemical system in multiple single cycles, and then formulates the energy target and energy consumption demand of the chemical system based on these parameters. Based on the energy target and energy consumption demand of the chemical system in each single cycle, a heat exchange network structure for the chemical system in that single cycle is designed. By integrating the heat exchange network structure and energy target of the chemical system in different single cycles, the installation position of the multi-layer energy storage units in the heat exchange network structure can be designed according to the integrated structure. This allows the multi-layer energy storage units to regulate the hot and cold flow streams in the heat exchange network structure across cycles, achieving waste heat recovery and utilization in different cycles. No additional heat exchangers are needed to achieve temperature rise and fall heat exchange for the hot and cold flow streams, thus solving the problems of significant heat energy waste and low energy utilization efficiency in existing chemical systems.

[0125] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0126] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0127] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0128] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0129] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0130] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0131] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for utilizing waste heat from chemical plants across multiple cycles, comprising multi-layer energy storage units, characterized in that, include: Obtain the flow parameters of the chemical system in multiple single cycles; Based on the flow parameters of the chemical system in multiple single cycles, the energy composite curve corresponding to each single cycle is plotted, and the pinch point temperature of the heat exchange network in each single cycle is obtained from the energy composite curve. Based on the energy composite curve, the utility usage of the chemical system in each single cycle is calculated; the pinch temperature and utility usage in each single cycle are integrated to obtain a multi-pinch temperature distribution map and the maximum and minimum utility usage in a single cycle. Based on the slope of the energy composite curve corresponding to the hot and cold flow streams, the energy composite curves corresponding to the multiple single cycles are divided into multiple blocks; based on the block parameters of each block, heat exchange network modeling and integration are performed on each block to obtain the heat exchange network structure of the chemical system; based on the maximum and minimum utility usage within the single cycle, the installation location and usage of the utilities required for the heat exchange network structure within each single cycle are calculated; The heat exchange network structure and energy target of the chemical system in multiple single cycles are integrated, and the installation position of the multi-layer energy storage unit in the chemical system is designed according to the integrated heat exchange network structure and energy target in order to carry out cross-cycle waste heat energy recovery and utilization.

2. The method for utilizing waste heat from cross-cycle chemical processes according to claim 1, characterized in that, The step of designing the installation location of the multi-layer energy storage unit in the chemical system based on the integrated heat exchange network structure and the energy target includes: Based on the heat exchange network structure and the installation location and quantity of the utilities required by the heat exchange network, determine the energy difference of the heat exchange network in each block within each single cycle; Based on the energy difference of the heat exchange network in each block within each single cycle, data modeling of the heat exchange network is performed to obtain the installation location of the multi-layer energy storage unit.

3. The method for utilizing waste heat from cross-cycle chemical processes according to claim 2, characterized in that, Following the step of designing the installation location of the multilayer energy storage unit in the chemical system based on the integrated heat exchange network structure and the energy target, the method further includes: Based on the block parameters of each of the multiple blocks, determine whether the heat exchange probability of the utility in each single cycle meets the minimum heat transfer temperature difference. If the heat exchange capability of the utility meets the minimum heat transfer temperature difference, then based on the energy difference information of the heat exchange network in each block, the energy storage unit at the corresponding installation location is controlled to perform cross-cycle heat charging and discharging utilization.

4. The method for utilizing waste heat from cross-cycle chemical processes according to claim 1, characterized in that, Following the step of designing the installation location of the multilayer energy storage unit in the chemical system based on the integrated heat exchange network structure and the energy target, the method further includes: Based on the installation location, size, and cost of the multi-layer energy storage unit, determine whether the multi-layer energy storage unit meets the economic requirements; If the multi-layer energy storage unit meets the economic requirements, then the heat exchange network structure containing the multi-layer energy storage unit is acquired and displayed.

5. A multi-cycle chemical waste heat utilization system comprising multi-layer energy storage units, characterized in that, include: The parameter acquisition module is used to acquire the flow parameters of the chemical system in multiple single cycles; The demand formulation module is used to formulate the energy target and energy consumption demand of the chemical system based on the flow parameters of the chemical system in multiple single cycles. The demand formulation module includes: a curve plotting submodule, used to plot the energy composite curve corresponding to each single cycle based on the flow parameters of the chemical system in multiple single cycles; a temperature acquisition submodule, used to obtain the pinch temperature of the heat exchange network in each single cycle from the energy composite curve; a usage calculation submodule, used to calculate the utility usage of the chemical system in each single cycle based on the energy composite curve; and a data integration submodule, used to integrate the pinch temperature and utility usage in each single cycle to obtain a multi-pinch temperature distribution map and the maximum and minimum utility usage within a single cycle. The structural calculation module is used to calculate the heat exchange network structure of the chemical system within each single cycle based on the energy target and energy consumption requirements of the chemical system within each single cycle. The structural calculation module includes: a curve division submodule, used to divide the energy composite curves corresponding to the multiple single cycles into multiple blocks based on the slope of the energy composite curves corresponding to the hot and cold flows; a modeling and integration submodule, used to perform heat exchange network modeling and integration for each block based on the block parameters of each block, to obtain the heat exchange network structure of the chemical system; and an engineering calculation submodule, used to calculate the installation location and quantity of utilities required for the heat exchange network structure within each single cycle based on the maximum and minimum utility usage within the single cycle. The location design module is used to integrate the heat exchange network structure and energy target of the chemical system in multiple single cycles, and to design the installation location of the multi-layer energy storage unit in the chemical system according to the integrated heat exchange network structure and energy target, so as to carry out cross-cycle waste heat energy recovery and utilization.

6. The cross-cycle chemical waste heat utilization system according to claim 5, characterized in that, The location design module includes: The energy difference calculation submodule is used to determine the energy difference of the heat exchange network in each block within each single cycle, based on the heat exchange network structure and the installation location and quantity of the utilities required by the heat exchange network. The data modeling submodule is used to perform data modeling on the heat exchange network based on the energy difference in each block of the heat exchange network within each single cycle, so as to obtain the installation location of the multi-layer energy storage unit.

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