Central energy lifting station regulation and control system and method based on industrial cold and heat balance

Abstract

The invention discloses a central energy lifting station regulation and control system and method based on industrial cold and heat balance, and belongs to the field of industrial waste heat energy-saving recycling. The system comprises an energy input end, an energy cache unit, a heat energy grade improving unit, an energy storage unit, an auxiliary and standby heat energy unit, an energy supply end and an intelligent central control unit. The system solves the problems of multiple types of waste heat sources, different high and low grades, heat consumption dispersion, large load fluctuation and the like during waste heat utilization of a factory, realizes unified allocation of waste heat and heat consumption of the whole factory, and solves the problems of point-to-point local energy saving and overall energy non-saving in the past.

Description

Technical Field

[0001] The present invention belongs to the field of energy-saving and reuse of industrial waste heat, and specifically relates to a central energy boosting station control system and method based on industrial cold and heat balance. Background Art

[0002] In the process of industrial production, a large amount of heat energy is consumed to meet specific process or processing requirements, but a large amount of waste heat is not utilized during the energy conversion and utilization process. According to relevant statistics, about 50% of the heat is directly discharged into the atmosphere, resulting in low waste heat energy utilization, which not only increases the energy cost of enterprises, but also aggravates carbon dioxide emissions.

[0003] At present, there are limitations to energy conservation in the industrial sector. Traditional energy conservation solutions are mainly reflected in the following aspects: first, the replacement of single equipment, that is, replacing single-point equipment with more efficient equipment; second, relying on the scale of production, replacing with larger equipment; third, focusing on "running, bubbling, dripping, and leaking" to improve the level of operation management. However, the above traditional energy-saving methods are unsustainable, and the energy-saving space is small, especially single-point energy conservation cannot achieve comprehensive energy-saving evaluation. Often, the energy-saving that seems to be effective at a single point does not bring the expected energy-saving effect from the perspective of the entire factory.

[0004] There are many types of waste heat sources in the industrial sector, with different grades. Using a single heat source cannot accurately match heat demand. There are also problems such as unstable waste heat, large and discontinuous load fluctuations, unsynchronized heat demand and heating time, and mismatch between supply and demand. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention proposes a central energy upgrading station control system and method based on industrial heat and cold balance. The system can collect and classify energy, upgrade the quality, and store it, and accurately match and output the corresponding energy medium according to different process energy requirements, make full use of waste heat to improve energy utilization, reduce carbon dioxide emissions, and achieve energy conservation and carbon reduction more widely and effectively.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: In a first aspect, the present invention provides a central energy boosting station control system based on industrial cold and heat balance, comprising: Energy input end, used to collect waste heat energy from various waste heat sources in the factory; An energy cache unit, used to classify and cache the waste heat energy collected from the energy input end; A thermal energy grade upgrading unit, used to upgrade the low-grade thermal energy stored in the energy cache unit to high-grade thermal energy; Energy storage unit, used to store high-grade thermal energy stored in energy cache unit or high-grade thermal energy output by thermal energy quality improvement system, and used as a reused heat source for peak load regulation to ensure smooth output of energy; Auxiliary and backup thermal energy units are used as auxiliary and backup thermal energy sources for energy storage units when process energy is started or load increases; The energy supply side is used to use the thermal energy stored in the energy storage unit as a heat source, match and output different energy media according to different process energy requirements, and provide for process production and daily use; The intelligent central control unit is used to monitor and adjust the energy flow of energy input, energy cache unit, energy storage unit, energy supply, auxiliary and backup thermal energy units in real time during the production process to ensure optimal utilization of energy.

[0007] In some preferred embodiments of the present invention, the energy input end includes a waste heat collection device, and the waste heat collection device adopts at least one of a heat exchanger, a waste heat storage tank, and a waste heat recovery device.

[0008] In some preferred embodiments of the present invention, the energy cache unit includes a high-temperature waste heat storage tank and a low-temperature waste heat storage tank.

[0009] In some preferred embodiments of the present invention, the thermal energy grade improving unit includes a thermal energy grade improving device, and the thermal energy grade improving device adopts at least one of a compression heat pump, an absorption heat pump, an induced heat pump, and a mechanical supercharger MVR.

[0010] In some preferred embodiments of the present invention, the energy storage unit comprises a high-grade thermal energy storage tank.

[0011] In some preferred embodiments of the present invention, the auxiliary and backup thermal energy units include auxiliary and backup heat source devices, and the auxiliary and backup heat source devices use original energy supply equipment of the process.

[0012] In some preferred embodiments of the present invention, the intelligent central control unit includes a PLC controller, and sensor groups are arranged on the waste heat collection device, high-temperature waste heat storage tank, low-temperature waste heat storage tank, thermal energy grade improvement device, high-grade thermal energy storage tank, auxiliary and backup heat source devices; each sensor group is electrically connected to the PLC controller.

[0013] In some preferred embodiments of the present invention, the sensor group includes a temperature sensor, a pressure sensor, and a flow sensor.

[0014] In some preferred embodiments of the present invention, the energy storage unit further includes a cold energy recovery tank, which is used to recover the low-temperature cold energy refluxed from each unit.

[0015] In a second aspect, the present invention provides a central energy lifting station control method based on industrial cold and heat balance, using the above-mentioned central energy lifting station control system based on industrial cold and heat balance, comprising: (1) Collect various types of waste heat from the factory through the energy input end, collect the temperature, flow and pressure parameters of various types of waste heat during the collection process, and then cache them in the energy cache unit according to their categories; (2) The high-temperature waste heat stored in the energy cache unit is directly sent to the energy storage unit, and the low-temperature waste heat stored in the energy cache unit is upgraded to high-grade thermal energy by the thermal energy grade upgrading unit and then sent to the energy storage unit; (3) The thermal energy stored in the energy storage unit is used as a heat source. The intelligent central control unit matches heat sources with different target temperatures according to the different temperatures required by the process, optimizes the heat exchange network, and outputs the matching energy medium required by the process through the energy supply end, thereby achieving cascade utilization of energy; (4) When the system is activated or encounters a fault or emergency, the original energy supply equipment of the process is selected as an auxiliary heat source and coupled to the energy storage unit to ensure that the residual value of the original energy supply equipment is brought into play without affecting the normal production of the process.

[0016] In some preferred embodiments of the present invention, the energy medium includes cooling water, hot water, electrical energy, and water vapor.

[0017] In some preferred embodiments of the present invention, the heat exchange network optimization is to perform integrated optimization of the heat exchange network through pinch point technology, establish an economic target mathematical model based on the combined temperature-enthalpy curve of cold and hot logistics, and optimize and calculate the optimal value of the pinch point temperature difference, specifically including: a. Input logistics parameters and cost data, assuming a minimum pinch point temperature difference ΔTmin; b. Draw the combined temperature-enthalpy curve of cold and hot logistics; c. Calculate the energy target, number of heat exchange units and area target; d. Calculate total cost target; e. Make the best judgment. If yes, output the result; if not, change ΔTmin and recalculate.

[0018] In some preferred embodiments of the present invention, the optimal judgment is achieved by constructing and calculating the total cost economic objective function, which specifically includes: (1) Calculate equipment investment cost C N : C N = na + ΣbA i C ; Among them, A i is the area of ​​a single heat exchanger, n is the number of heat exchanger units, a, b and c are price coefficients; (2) Calculation of public works costs C E : C E =C H +C L ; Among them, C H and C L Utility costs for heating and cooling, respectively; (3) Calculate the operating cost Co: Co=C F ΣW Fi ; Among them, W Fi is the power consumed in the system, C F For local electricity charges; (4) Calculate the total cost C: MinC=C N / r+(C E +Co)t Where r is the depreciation period of the equipment; t is the annual operating time.

[0019] Compared with the prior art, the beneficial technical effects of the present invention are: 1. The system and method of the present invention recycles and utilizes various types of waste heat in the factory, uniformly allocates cold and heat in the whole factory, meets the factory's demand for cold or heat, replaces the original boiler equipment or external network steam, saves primary energy consumption, and achieves overall effective energy saving; high-grade waste heat can be directly recycled and utilized through a heat exchanger, and low-grade waste heat can be upgraded to more high-grade heat through heat pump technology. The COP value of the thermal energy grade upgrading device used is usually greater than 2, that is, the recycled waste heat is upgraded to more high-grade heat by consuming a small amount of electricity or heat, which expands the scope of waste heat utilization, saves primary energy, and reduces energy costs; at the same time, in the entire waste heat utilization process, the heat originally discharged through the cooling tower or refrigerator is recycled through the energy input end, reducing the refrigeration load; the energy supply end can change the medium and low pressure steam into lower-grade hot water according to the process requirements, reduce the heat transfer temperature difference, and improve energy utilization.

[0020] 2. The system and method of the present invention can transform the energy structure and achieve decarbonization and zero carbon. The main energy consumption of the thermal energy grade improvement device is electricity. The waste heat and a part of the electricity are used to replace the original coal and natural gas, thereby improving the original energy structure, reducing carbon emissions, and achieving low carbon and zero carbon.

[0021] 3. The system and method of the present invention solve the problems existing in the utilization of factory waste heat, such as the variety of waste heat sources, different high and low grades, dispersed heat use, large load fluctuations, etc., and realize the unified allocation of waste heat and heat use in the whole factory, changing the previous problem of point-to-point local energy saving and overall non-energy saving.

[0022] 4. The system and method of the present invention optimize and expand the waste heat utilization scenarios, change the process energy structure, and conduct in-depth research on the hot spots by investigating the process energy environment of the whole plant, so as to find the application scenarios suitable for waste heat, so that the waste heat can be recovered and utilized more effectively, and the recycling rate of the cold and hot systems can be improved. For example, by replacing steam (high-quality heat) with high-temperature hot water (lower-quality heat), the heat transfer temperature difference can be reduced and the economy of the system can be improved; at the same time, by deeply exploring the user's process and optimizing the heat exchange network, the user's optimal energy utilization efficiency can be matched, and the efficient utilization of waste heat can be achieved, solving the problem of insufficient utilization of waste heat after recovery in traditional industries.

[0023] 5. The present invention uses pinch point technology to optimize the heat exchange network, determine the minimum heat transfer temperature difference of the heat exchange network, fully recover the heat energy of the process itself, improve energy efficiency, reduce public works and equipment investment costs, reduce operating costs, make the use of waste heat more efficient, and achieve overall energy storage and improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a structural block diagram of a central energy boosting station control system based on industrial cold and heat balance of the present invention; Figure 2 It is a flow chart of heat exchange network integrated optimization using pinch point technology in the present invention; Figure numerals: 1-energy input end, 2-energy cache unit, 3-thermal energy quality improvement unit, 4-energy storage unit, 5-energy supply end, 6-auxiliary and backup thermal energy unit, 7-intelligent central control unit. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely in conjunction with the embodiments below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1 Please see attached Figure 1As shown, a central energy upgrading station control system based on industrial cold and heat balance in this embodiment includes an energy input terminal 1, an energy cache unit 2, a thermal energy quality improvement unit 3, an energy storage unit 4, an auxiliary and backup thermal energy unit 6, an energy supply terminal 5 and an intelligent central control unit 7.

[0028] Specifically, the energy input terminal 1 is used to collect waste heat energy from various waste heat sources such as process wastewater, waste gas, flash steam, air compressor waste heat, cooling tower circulating water, etc. in the factory; the energy input terminal 1 includes a waste heat collection device, and the waste heat collection device adopts at least one of a heat exchanger, a waste heat storage tank, and a waste heat recovery device. There are many types of waste heat in the factory and they are scattered. Through the collection and classification of waste heat, the scattered waste heat resources can be centrally managed, and different utilization strategies can be formulated for heat sources of different grades. At the same time, the effective collection of waste heat provides the necessary basis for the unified allocation and optimization of the heat exchange network of the whole plant. According to the quality, quantity and user needs of the waste heat, the cascade utilization is realized in accordance with the energy level matching method, which can more accurately match the demand and supply of thermal energy, minimize the heat transfer temperature difference, and thus achieve efficient utilization of energy and ensure the optimized operation of the system.

[0029] Specifically, the energy cache unit 2 is used to cache the waste heat energy collected by the energy input end 1 in a classified manner, and the energy cache unit 2 includes a high-temperature waste heat storage tank and a low-temperature waste heat storage tank. As an intermediate buffer device, the energy cache unit 2 is conducive to ensuring process safety and stable operation of the system when the waste heat is unstable and the parameters (temperature, flow) fluctuate.

[0030] Specifically, the thermal energy quality improvement unit 3 is used to improve the low-quality thermal energy stored in the energy cache unit 2 to high-quality thermal energy. The thermal energy quality improvement unit 3 includes a thermal energy quality improvement device, which uses at least one of a compression heat pump, an absorption heat pump, an induced heat pump, and a mechanical supercharger MVR. Since low-temperature waste heat cannot be used directly, it can only be used for process production, workshop heating, and domestic hot water after being upgraded to high-quality thermal energy through heat pump technology. Different single technologies or a combination of the above technologies are selected according to different needs.

[0031] Specifically, the energy storage unit 4 is used to store the high-grade thermal energy stored in the energy cache unit 2 or the high-grade thermal energy output by the thermal energy quality improvement system, and is used as a reused heat source for peak load regulation to ensure smooth energy output; the energy storage unit 4 includes a high-grade thermal energy storage tank and a cold energy recovery tank, and the cold energy recovery tank is used to recover the low-temperature cold energy refluxed from each unit. In order to solve the problems of unstable waste heat, large and discontinuous load fluctuations, asynchronous heat use and heat supply time, and mismatch between supply and demand, energy storage equipment is added to regulate the peak load, reduce the peak load and fill the valley, cope with peak loads, achieve water balance and heat balance, so as to achieve better equipment investment; the energy storage unit 4 can use hot water storage tanks, solid energy storage, phase change material energy storage, etc.

[0032] Specifically, the auxiliary and standby thermal energy unit 6 is used as an auxiliary and standby thermal energy source for the energy storage unit 4 when the process energy is started or the load increases; the auxiliary and standby thermal energy unit 6 includes an auxiliary and standby heat source device, which adopts the original energy supply equipment of the process, such as a heat exchanger or a steam boiler, and converts steam into hot water through the heat exchange equipment, which is coupled to the system, so as to give play to the surplus value of the original energy supply equipment while ensuring that the normal production of the process is not affected.

[0033] Specifically, the energy supply end 5 is used to use the thermal energy stored in the energy storage unit 4 as a heat source, match and output different energy media according to different process energy requirements, for process production and life use. The energy supply end 5 includes a process production heat exchanger, a domestic hot water heat exchanger, a winter heating heat exchanger, and a summer cooling heat exchanger.

[0034] Specifically, the intelligent central control unit 7 is used to monitor and adjust the energy flow of the energy input terminal 1, the energy cache unit 2, the energy storage unit 4, the energy supply terminal 5, and the auxiliary and standby thermal energy unit 6 in the production process in real time to ensure the optimal use of energy; the intelligent central control unit 7 includes a PLC controller, and the waste heat collection device, the high-temperature waste heat storage tank, the low-temperature waste heat storage tank, the heat energy grade improvement device, the high-grade heat energy storage tank, the auxiliary and standby heat source device are all provided with a sensor group, and the sensor group includes a temperature sensor, a pressure sensor, and a flow sensor; each sensor group is electrically connected to the PLC controller. The intelligent central control unit 7 collects the multi-energy energy consumption data of the enterprise, combines the algorithm capability to provide the enterprise with load forecasting, energy use anomalies, and energy use suggestions, assists enterprise managers in making energy use optimization decisions, and helps the enterprise achieve energy conservation and emission reduction.

[0035] Example 2 This embodiment provides a central energy boosting station control method based on industrial cold and heat balance, using the central energy boosting station control system based on industrial cold and heat balance of embodiment 1, including: (1) Various types of waste heat from the factory are collected through the energy input terminal 1. During the collection process, the temperature, flow rate and pressure parameters of various types of waste heat are collected, and then classified and cached in the energy cache unit 2; (2) The high-temperature waste heat stored in the energy cache unit 2 is directly sent to the energy storage unit 4, and the low-temperature waste heat stored in the energy cache unit 2 is upgraded to high-quality thermal energy by the thermal energy grade upgrading unit 3 and then sent to the energy storage unit 4; (3) The heat energy stored in the energy storage unit 4 is used as a heat source. The intelligent central control unit 7 matches heat sources with different target temperatures according to the different temperatures required by the process, optimizes the heat exchange network, and outputs the matching energy medium required by the process through the energy supply end 5 to achieve cascade utilization of energy; (4) When the system is activated or encounters a fault or emergency, the original energy supply equipment of the process is selected as an auxiliary heat source and coupled to the energy storage unit 4 to ensure that the residual value of the original energy supply equipment is brought into play without affecting the normal production of the process.

[0036] In this embodiment, the energy medium includes cooling water, hot water, electric energy, water vapor, ethylene glycol, thermal oil, etc. The intelligent central control unit 7 controls the energy supply end 5 to convert the energy structure and output different energy media to match the heat source required by the process.

[0037] Please refer to the attached Figure 2 In this embodiment, the heat exchange network optimization is to optimize the heat exchange network integration through the pinch point technology, establish the economic target mathematical model according to the combined temperature-enthalpy curve of the cold and hot logistics, and optimize the calculation of the optimal value of the pinch point temperature difference, which specifically includes: a. Input logistics parameters and cost data, assuming a minimum pinch point temperature difference ΔTmin; b. Draw the combined temperature-enthalpy curve of cold and hot logistics; c. Calculate the energy target, number of heat exchange units and area target; d. Calculate total cost target; e. Make the best judgment. If yes, output the result; if not, change ΔTmin and recalculate.

[0038] In this embodiment, the optimal judgment is achieved by constructing and calculating the total cost economic objective function, which specifically includes: (1) Calculate equipment investment cost C N : C N = na + ΣbA i C ; Among them, A i is the area of ​​a single heat exchanger, n is the number of heat exchanger units, a, b and c are price coefficients; (2) Calculation of public works costs C E : C E =C H +C L ; Among them, C H and C L Utility costs for heating and cooling, respectively; (3) Calculate the operating cost Co: Co=C F ΣW Fi ; Among them, W Fi is the power consumed in the system, C F For local electricity charges; (4) Calculate the total cost C: MinC=C N / r+(C E +Co)t Where r is the depreciation period of the equipment; t is the annual operating time.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the technical solution and conceptual invention of the present invention should be included in the protection scope of the present invention.

Claims

1. A central energy boosting station control system based on industrial heat and cold balance, characterized in that: include: Energy input end, used to collect waste heat energy from various waste heat sources in the factory; An energy cache unit, used to classify and cache the waste heat energy collected from the energy input end; A thermal energy grade upgrading unit, used to upgrade the low-grade thermal energy stored in the energy cache unit to high-grade thermal energy; Energy storage unit, used to store high-grade thermal energy stored in energy cache unit or high-grade thermal energy output by thermal energy quality improvement system, and used as a reused heat source for peak load regulation to ensure smooth output of energy; Auxiliary and backup thermal energy units are used as auxiliary and backup thermal energy sources for energy storage units when process energy is started or load increases; The energy supply side is used to use the thermal energy stored in the energy storage unit as a heat source, match and output different energy media according to different process energy requirements, and provide for process production and daily use; The intelligent central control unit is used to monitor and adjust the energy flow of energy input, energy cache unit, energy storage unit, energy supply, auxiliary and backup thermal energy units in real time during the production process to ensure optimal utilization of energy.

2. According to claim 1, a central energy boosting station control system based on industrial cold and heat balance is characterized by: The energy input end includes a waste heat collection device, which is at least one of a heat exchanger, a waste heat storage tank, and a waste heat recovery device; The energy cache unit includes a high-temperature waste heat storage tank and a low-temperature waste heat storage tank; The thermal energy grade improvement unit includes a thermal energy grade improvement device, which adopts at least one of a compression heat pump, an absorption heat pump, an ejection heat pump, and a mechanical supercharger MVR; The energy storage unit includes a high-grade thermal energy storage tank; The auxiliary and standby heat energy units include auxiliary and standby heat source devices, which use the original energy supply equipment of the process; The intelligent central control unit includes a PLC controller; The waste heat collection device, high-temperature waste heat storage tank, low-temperature waste heat storage tank, thermal energy grade improvement device, high-grade thermal energy storage tank, auxiliary and backup heat source devices are all provided with sensor groups; each sensor group is electrically connected to the PLC controller; The sensor group includes a temperature sensor, a pressure sensor, and a flow sensor.

3. According to claim 2, a central energy boosting station control system based on industrial cold and heat balance is characterized by: The energy storage unit also includes a cold energy recovery tank, which is used to recover the low-temperature cold energy refluxed from each unit.

4. A central energy boosting station control method based on industrial heat and cold balance, using a central energy boosting station control system based on industrial heat and cold balance as described in claim 3, characterized in that: include: (1) Collect various types of waste heat from the factory through the energy input end, collect the temperature, flow and pressure parameters of various types of waste heat during the collection process, and then cache them in the energy cache unit according to their categories; (2) The high-temperature waste heat stored in the energy cache unit is directly sent to the energy storage unit, and the low-temperature waste heat stored in the energy cache unit is upgraded to high-grade thermal energy by the thermal energy grade upgrading unit and then sent to the energy storage unit; (3) The thermal energy stored in the energy storage unit is used as a heat source. The intelligent central control unit matches heat sources with different target temperatures according to the different temperatures required by the process, optimizes the heat exchange network, and outputs the matching energy medium required by the process through the energy supply end, thereby achieving cascade utilization of energy; (4) When the system is activated or encounters a fault or emergency, the original energy supply equipment of the process is selected as an auxiliary heat source and coupled to the energy storage unit to ensure that the residual value of the original energy supply equipment is brought into play without affecting the normal production of the process.

5. The central energy boosting station control method based on industrial cold and heat balance according to claim 4 is characterized by: The energy medium includes cooling water, hot water, electric energy and water vapor.

6. A central energy boosting station control method based on industrial cold and heat balance according to claim 5, characterized in that: The heat exchange network optimization is to optimize the heat exchange network integration through the pinch point technology, establish the economic target mathematical model according to the combined temperature-enthalpy curve of the cold and hot logistics, and optimize the calculation of the optimal value of the pinch point temperature difference, which specifically includes: a. Input logistics parameters and cost data, assuming a minimum pinch point temperature difference ΔT min ; b. Draw the combined temperature-enthalpy curve of cold and hot logistics; c. Calculate the energy target, number of heat exchange units and area target; d. Calculate total cost target; e. Make the best judgment, if yes, output the result; if no, change ΔT min Recalculate.

7. The central energy boosting station control method based on industrial cold and heat balance according to claim 3 is characterized by: The optimal judgment is achieved by constructing and calculating the total cost economic objective function, which specifically includes: (1) Calculate equipment investment cost C N : C N = na+ΣbA i C ; Among them, A i is the area of ​​a single heat exchanger, n is the number of heat exchanger units, a, b and c are price coefficients; (2) Calculation of public works costs C E : C E =C H +C L ; Among them, C H and C L Utility costs for heating and cooling, respectively; (3) Calculate the operating cost Co: Co=C F ΣW Fi ; Among them, W Fi is the power consumed in the system, C F For local electricity charges; (4) Calculate the total cost C: MinC=C N / r+(C E +Co)t Where r is the depreciation period of the equipment and t is the annual operating time.

Images