Comprehensive energy system optimization scheduling method considering demand response and containing waste incineration power plant

Abstract

The invention belongs to the technical field of economic operation of comprehensive energy systems, and discloses a comprehensive energy system optimal scheduling method considering demand response and containing a waste incineration power plant, which considers cooperative operation of the waste incineration power plant, a carbon capture device and power-to-gas equipment, and synthesizes recycled carbon dioxide into methane by introducing the carbon capture device and the power-to-gas equipment. Cyclic utilization of carbon is realized; scheduling resources on the supply side and the demand side are excavated, and an organic Rankine cycle waste heat power generation and flue gas waste heat recovery device is added to the energy supply side to construct an electric heat flexible output model of the energy supply side; based on a stepped carbon transaction mechanism, an electric-thermal integrated energy system optimization scheduling model with the minimum system operation cost as the target is constructed, a CPLEX optimization engine is used for solving the model, and the result verifies the effectiveness of the constructed model. The method can effectively guide the user to participate in the demand response to improve the economical efficiency and flexibility of the system and promote the consumption capability of renewable energy sources, and has the advantages of being scientific, reasonable, high in applicability, good in effect and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of economic operation of integrated energy systems, and in particular relates to low-carbon economic dispatching of integrated energy systems including waste incineration power plants taking into account responses on both supply and demand sides. Background Art

[0002] At present, combining carbon trading and green certificate trading mechanisms, tapping demand-side resources will help achieve the low-carbon economic development of the Integrated Energy System (IES) and establish a flexible integrated demand response model with coordinated source and load. In recent years, the volume of garbage produced by people's production and life is huge, and garbage incineration power plants have the characteristics of "reduction, harmlessness, and resource utilization". Compared with remote thermal power plants, garbage incineration power plants built near urban areas have more geographical advantages and are more conducive to urban power supply and heating services. Garbage incineration power generation technology not only effectively solves urban domestic garbage, but also increases the possibility of sustainable energy development. Garbage incineration power generation is a key product of social development. Using garbage incineration power generation can effectively prevent garbage overflow and realize the recycling and harmless utilization of garbage resources. Garbage incineration power generation can alleviate the problem of electricity shortage in some cities. Due to the increasing global environmental problems, traditional energy power generation not only cannot alleviate the problem of urban electricity shortage, but also further aggravates urban pollution. Integrated demand response (IDR) is an important controllable resource in IES operation. Fully utilizing it can smooth the load curve, improve the consumption of new energy and improve the economic efficiency of operation.

[0003] The low-carbon development model is of great significance to solving the contradiction between new energy and traditional power generation units and realizing the mutual coupling between multiple energy sources. Two major trading policies, the carbon emission trading (CET) mechanism and the green certificate trading (GCT) mechanism, have emerged, playing an important role in reducing carbon emissions and promoting the consumption of new energy. Similar to CET, the application of GCT in IES scheduling also reflects the positive externalities of renewable energy through costs, that is, taking the GCT cost as part of the objective function and then calculating the scheduling plan. Using the use of renewable energy electricity (green electricity) to measure the low-carbon or zero-carbon level of enterprises has become the focus of attention of various market players.

[0004] Therefore, the existing technology urgently needs a new comprehensive energy optimization scheduling method to solve the above problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an optimization scheduling method for an integrated energy system including a waste incineration power plant taking into account demand response, which can effectively guide users to participate in demand response to improve the economy and flexibility of the system and promote the absorption capacity of renewable energy. The method has the advantages of scientific and reasonable method, strong applicability and good effect.

[0006] The optimization scheduling method of the integrated energy system including the waste incineration power plant considering demand response includes the following steps:

[0007] Step 1: Construct an IES physical model including a waste incineration power plant that takes into account the response on both the supply and demand sides;

[0008] Step 2: Construct an operation model of a combined heat and power (CHP) unit after introducing an organic Rankine cycle (ORC). The heat output of the CHP unit after introducing ORC includes two flow modes, namely, supplying heat load through a waste heat boiler (WHB) and generating electricity through waste heat through ORC.

[0009] Step 3: Construct a waste incineration-flue gas treatment-waste heat recovery system operation model. Add a waste heat recovery device on the basis of the traditional flue gas treatment and purification device to recover the waste heat in the flue gas and reduce CO2 emissions. When the electrical energy is greater than the thermal energy, recover the heat of the emitted flue gas and perform an electric heating response on the energy supply side.

[0010] Step 4: Establish an electric and thermal load demand response model on the load side. The electric and thermal loads are transferred in their respective time dimensions and replace each other in the same period. Any load consists of three parts: fixed load, transferable load and alternative load.

[0011] Step 5: Establish a ladder carbon trading mechanism model. The electrolyzer converts H2O into two gases, H2 and O2. H2 enters the next stage and is transported to the methane reactor to synthesize natural gas with CO2. It can be supplied to cogeneration and gas boilers (GB) to give full play to the dispatch value of both the source and load sides of the integrated energy system, improve the new energy consumption rate, and reduce the system operation cost.

[0012] Step 6: With the goal of minimizing the IES low-carbon economic operation cost, construct the objective function and constraints, and formulate a scheduling strategy.

[0013] The IES physical models described in step 1 are as follows: the energy supply side includes the power grid, natural gas market, wind turbines and waste incineration power plants; the coupling equipment part includes electrolyzers, methanation reaction equipment, gas boilers and ORC waste heat power generation devices; the terminal energy consumption part includes electrical loads and thermal loads.

[0014] The operation model of the CHP unit after the introduction of ORC in step 2 is:

[0015]

[0016] In the formula, is the thermal power of ORC waste heat recovery in the CHP unit; is the thermal power output by WHB; is the power generation of ORC waste heat recovery; η ORC is the electric-to-thermal conversion efficiency of ORC; and They are The minimum and maximum values ​​of and They are The upper and lower limits of the climbing rate, is the thermal power output of the CHP unit.

[0017] The operation model of the waste incineration-flue gas treatment-waste heat recovery system described in step 3 is expressed by the gas boiler GB model as follows:

[0018]

[0019] Where P GB,h (t) is the thermal power output of GB unit; P g,GB (t) is the input GB gas power; η GB is the efficiency of input GB during period t; They are the maximum and minimum climbing values ​​of GB respectively; are the maximum and minimum values ​​of the input gas power respectively.

[0020] The electric heating load demand response model described in step 4 is:

[0021]

[0022] In the formula, k is the type of electrical and thermal load; is the value of the fixed load in period t; is the value of the transferable load in period t; is the value of the replaceable load in period t.

[0023] The ladder carbon trading mechanism model described in step 5 is:

[0024] Under the carbon trading mechanism, carbon emissions are traded free of charge, and the free carbon emissions quota is allocated as follows:

[0025]

[0026] In the formula, EIES 、E e,buy 、E CHP 、E GB 、E WI They are the free carbon emission quotas of the integrated energy system, external power purchase, CHP system, GB and waste incineration power plant; β e , β h , β w are the free carbon emission coefficients of electricity purchased from the external grid, heat generated by GB, and electricity generated by the waste incineration power plant; P e,buy (t) is the system's purchased power at time t; P CHP (t), H CHP (t) are the output power of electric energy and thermal energy of CHP at time t; H GB (t) is the output thermal power of the gas boiler at time t; φ e,h is the equivalent heat conversion factor of the CHP equipment power generation, P WI (t) is the output power of the waste incineration power plant at time t.

[0027] The actual carbon emissions of IES are:

[0028]

[0029] In the formula, They are the actual carbon emissions of the integrated energy system, external power purchase, CHP system, GB, and waste incineration power plant; is the carbon absorption capacity of P2G; β g , β c are the actual carbon emission coefficients of P2G and CCS, P P2G (t), P CCS (t) are the energy consumption of P2G equipment and carbon capture equipment, respectively.

[0030] The tiered pricing mechanism is used to calculate the carbon trading costs. The calculation formula is:

[0031]

[0032] In the formula, α is the carbon trading price growth coefficient; c is the carbon trading base price; d is the length of the carbon trading price range; ΔE is the difference between the actual carbon emissions of the integrated energy system and the free carbon emission quota.

[0033] The carbon trading volume ΔE in the tiered carbon emission trading cost is:

[0034]

[0035] The objective function in step six is:

[0036]

[0037] Where, F is the IES low-carbon economic operation cost; They are electricity purchase cost, gas purchase cost, waste incineration power plant cost, tiered carbon trading cost, demand-side response compensation cost, P2G cost, and wind curtailment cost.

[0038] The constraints described in step six include wind power output constraints, electric and thermal energy storage operation constraints, electric power balance constraints, thermal power balance constraints and gas power balance constraints.

[0039] Through the above design scheme, the present invention can bring the following beneficial effects: considering the demand response of the integrated energy system optimization scheduling method including the waste incineration power plant, on the one hand, considering the coordinated operation of the waste incineration power plant-carbon capture device-power-to-gas equipment, by introducing the carbon capture device and the power-to-gas equipment to synthesize the recovered carbon dioxide into methane, and realize the recycling of carbon; secondly, fully tap the dispatchable resources on both the supply and demand sides, add the organic Rankine cycle waste heat power generation and flue gas waste heat recovery device on the energy supply side to construct the electric and thermal flexible output model on the energy supply side. Finally, based on the step-by-step carbon trading mechanism, an optimized scheduling model of the electric-thermal integrated energy system with the minimum system operating cost as the goal is constructed, and the CPLEX optimization engine is used to solve this model, and the results verify the effectiveness of the constructed model. It can effectively guide users to participate in demand response to improve the economy and flexibility of the system, promote the absorption capacity of renewable energy, and has the advantages of scientific and reasonable methods, strong applicability, and good effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0041] Figure 1 It is a schematic diagram of a low-carbon economic dispatching process of a comprehensive energy system including a waste incineration power plant taking into account the response of both supply and demand sides of the present invention;

[0042] Figure 2 It is a schematic diagram of the IES physical model including a waste incineration power plant considering the response of both supply and demand sides of the present invention;

[0043] Figure 3 It is a schematic diagram of the CO2 separation device and waste heat recovery device of the present invention;

[0044] Figure 4 Schematic diagram of the relationship between COP and low-temperature heat source temperature of the present invention;

[0045] Figure 5 It is a schematic diagram of the carbon utilization process of the present invention;

[0046] Figure 6 This is a schematic diagram of the prediction of various loads and wind-solar output conditions of the present invention;

[0047] Figure 7 This is a schematic diagram of the electrical load and output of each power supply unit in mode 1 of the present invention;

[0048] Figure 8 This is a schematic diagram of the flexible response of the electricity-heat demand side in Mode 2 of the present invention;

[0049] Fig. 9 It is a schematic diagram of the electric load and the output of each power supply unit in Mode 3 of the present invention;

[0050] Fig.10 It is a schematic diagram of the heat load and output of each heating unit in Modes 3 and 4 of the present invention;

[0051] Fig.11 This is a schematic diagram of high-temperature flue gas diversion according to the present invention;

[0052] Fig.12 This is a schematic diagram of the electrical load and output of each power supply unit in Mode 4 of the present invention;

[0053] Fig.13 It is a schematic diagram of CO2 emission and capture amount of the present invention. DETAILED DESCRIPTION

[0054] Optimal dispatch method for integrated energy system including waste incineration power plant considering demand response, see Figure 1 , considering the response of both supply and demand sides, the low-carbon economic dispatch of the integrated energy system including the waste incineration power plant is characterized by, firstly, constructing the physical model of the integrated energy system including the waste incineration power plant considering the response of both supply and demand sides, and then constructing the optimization dispatch model of the electric-thermal integrated energy system with the goal of minimizing the system operation cost based on the step-by-step carbon trading mechanism, considering the coordinated operation of the waste incineration power plant-carbon capture device-power-to-gas equipment, and synthesizing methane from the recovered carbon dioxide by introducing the carbon capture device and the power-to-gas equipment to realize the recycling of carbon and fully tap the dispatchable resources on both the supply and demand sides, and adding the organic Rankine cycle waste heat power generation and flue gas waste heat recovery device on the energy supply side to construct the electric-thermal flexible output model on the energy supply side. Finally, the CPLEX optimization engine is used to solve this model, and the results verify the effectiveness of the constructed model. The specific steps include:

[0055] 1) See Figure 2, an IES physical model including a waste incineration power plant is constructed considering the response on both the supply and demand sides. The integrated energy system scheduling block diagram established by the present invention mainly includes three parts: the energy supply side includes the power grid, the natural gas market, wind turbines, and the waste incineration power plant; the coupling equipment part includes energy conversion equipment such as electrolyzers, methanation reaction equipment, gas boilers, and ORC waste heat power generation devices; the terminal energy consumption part includes two types of loads: electricity and heat.

[0056] 2) Introducing ORC waste heat power generation, the heat output of the CHP unit has two flow modes, namely supplying heat load through WHB and generating electricity through ORC. Combining ORC with CHP can convert heat energy into electrical energy when heat energy is sufficient and electrical energy is insufficient, thus improving the flexibility of electrical and thermal output of the unit.

[0057] The CHP unit consists of a gas turbine (GT) and a waste heat boiler (WHB), which uses natural gas as fuel to produce heat and electricity. However, due to the peak-shifting characteristics of the electricity and heat load trends, the CHP is limited by the "heat-to-electricity" constraint, and its energy supply flexibility is poor. After the introduction of ORC waste heat power generation, the thermal output of the CHP unit has two flow modes, namely supplying heat load through WHB and generating electricity through ORC. Combining ORC with CHP can convert thermal energy into electrical energy when thermal energy is sufficient and electrical energy is insufficient, thereby improving the flexibility of the unit's electrical and thermal output. The CHP model can be expressed as:

[0058]

[0059] Where P CHP,e (t), P CHP,h (t), P g,CHP (t) are the electricity, heat and natural gas power output of CHP in period t, respectively; are the efficiency of natural gas conversion into electricity and heat energy in the unit respectively; are the maximum and minimum values ​​of natural gas power input to CHP respectively; are the upper and lower limits of CHP climbing respectively; P GB (t) is the thermal power output of GB unit during period t; V GB is the amount of natural gas consumed by unit GB during period t.

[0060] After the introduction of ORC, the ORC and WHB models can be expressed as:

[0061]

[0062] In the formula, is the thermal power of ORC waste heat recovery in the CHP unit; is the thermal power output by WHB; is the power generation of ORC waste heat recovery; η ORC is the electric-to-thermal conversion efficiency of ORC; and They are The minimum and maximum values ​​of and They are The upper and lower limits of the climbing rate.

[0063] 3) Introducing a waste heat recovery device on the basis of the traditional flue gas treatment and purification device can recover as much waste heat as possible in the flue gas and reduce CO2 emissions. When electricity is sufficient but thermal energy is insufficient, part of the electricity is consumed to recover the heat of the emitted flue gas, further realizing flexible response of electricity and heat on the energy supply side.

[0064] The garbage incineration-flue gas treatment-waste heat recovery system consists of an incinerator, a flue gas purification device, a waste heat utilization device, etc. First, the urban garbage is sent to the storage bin for pre-treatment processes such as static, dehydration, and drying, and then sent to the incinerator to burn and release internal chemical energy. The generated steam is sent to the steam turbine unit to generate electricity and heat energy. During the incineration process, the garbage emits a large amount of flue gas containing harmful substances such as sulfide, dioxin, and particulate matter, which needs to be sent to the flue gas purification device for qualified treatment before discharge. The flue gas treatment device has a high energy consumption, generally accounting for 25% of its total power generation.

[0065] Since the daily waste treatment volume of the waste incineration power plant is constant, its total daily output is a certain value:

[0066]

[0067] Where W WI The daily total output of the waste incineration power plant is a constant; P WIE,max , P WIE,min are the maximum and minimum output at each moment respectively; P WI is the net output of the waste incineration power plant, η YR is the flue gas energy consumption coefficient.

[0068] The GB model of gas boiler can be expressed as:

[0069]

[0070] Where P GB,h (t) is the thermal power output of GB unit; P g,GB (t) is the input GB gas power; η GB is the efficiency of input GB during period t; They are the maximum and minimum climbing values ​​of GB respectively; are the maximum and minimum values ​​of the input gas power respectively.

[0071] At present, the flue gas purification treatment system commonly used in domestic waste incineration projects in my country adopts the combined process of "SNCR + semi-dry method + dry method + activated carbon injection + bag dust removal". In order to prevent the survival of bag dust removal devices in flue gas treatment, the temperature of the flue gas after treatment in waste incineration power plants is generally around 180-210℃, and contains a large amount of latent heat water vapor, accounting for 26.39% of the flue gas. About 40MW·h of waste heat can be recovered from the flue gas generated by the incinerator that processes 200 tons of garbage per day; while gas boilers (GB) use natural gas, mainly methane, as fuel for heat production, and the combustion products contain nearly 20% water vapor. In order to prevent the exhaust gas from causing corrosion to the boiler device, the exhaust gas temperature of the heating boiler is usually set relatively high, reaching about 200℃. If the exhaust gas of the gas boiler is utilized, the heat of 13.35% of the calorific value of natural gas can also be sent to the heat network. At the same time, according to a report released by the Evaluation Center of the Ministry of Ecology and Environment: the CO2 emissions of a waste incineration power plant for processing one ton of waste is about 358 kilograms. With the development of the carbon trading market and the supervision of greenhouse gas emissions such as CO2, there will be penalty costs if CO2 emissions exceed the limit.

[0072] Figure 3 The CO2 capture and waste heat recovery device shown is intended to recover as much waste heat as possible from the flue gas and reduce CO2 emissions.

[0073] The high-temperature flue gas first passes through the flue gas purification treatment device (absorption tower, bag dust removal device) to complete the adsorption and interception of harmful substances emitted by the flue gas. The top of the spray tower is a demisting area to prevent water vapor and fog from being discharged with the purified high-temperature flue gas. 3 to 4 layers of spray guns are set in the tower to spray circulating atomized water and mix with the high-temperature flue gas to exchange heat, so that the flue gas temperature drops to 39-45°C to release sensible heat, and the water vapor contained in the flue gas condenses to release latent heat, thereby exchanging the heat in the gas into the water. After the heat exchange is completed, the flue gas cooling water temperature can reach 35°C, but this temperature does not reach the central heating water temperature specified in northern cities. Therefore, water source heat pump equipment is further used, with a low-temperature heat source (cooled waste hot water) as the driving heat source. After evaporation, compression, condensation and other steps, only a small amount of electricity is consumed to achieve the purpose of transporting heat energy from low temperature to high temperature.

[0074] The flue gas at the outlet of the spray tower enters the CO2 separation device under the action of the induced draft fan. After the above treatment, the remaining components in the flue gas are mainly CO2, O2 and N2. Therefore, it only needs to be simply separated and treated to transport CO2 as a raw material to the methanation reaction equipment in the P2G. This method only requires a small amount of energy consumption to be equivalent to the role of the CO2 capture device. The model of the flue gas separation and waste heat recovery device is as follows:

[0075] At time t, the power consumption of the flue gas separation device for separating CO2 is P Cf,t ,Right now:

[0076] P Cf,t =λ·V C,t (6)

[0077] V C,t =γ·β·V 0,t (7)

[0078] In the formula, the volume of CO2 separated at time t is V C,t ; The power consumption per unit CO2 separation is λ; The CO2 separation rate is β; The proportion of CO2 in the flue gas is γ. The waste heat recovered by the waste heat recovery device is:

[0079] Q1=λ1·Q Y (8)

[0080] In the formula, the energy efficiency of the spray tower is λ1, and the energy contained in the flue gas is Q Y .

[0081] Figure 4 It is the relationship between the energy efficiency coefficient COP of water source heat pump and the water temperature on the water supply side. The water supply temperature of the secondary heating network in northern cities in China is generally 55-65℃, and the return water temperature is generally 50℃. According to the principle of water source heat pump equipment, the inlet water temperature of the waste water source is positively correlated with the heat exchange efficiency of the heat pump. Therefore, increasing the waste water temperature can improve the heat exchange efficiency.

[0082] The energy efficiency function of water source heat pump is:

[0083] P p,t COP = Q p,t (9)

[0084] In the formula, the power consumption of the water source heat pump at time t is P P , the performance function of the water source heat pump is COP, and the outlet heat of the water source heat pump at time t is Q p,t .

[0085] The water source heat pump constraints are:

[0086]

[0087] In the formula, It is the maximum power consumption of water source heat pump.

[0088] The relationship between the low-temperature heat source temperature and COP of the equipment is fitted to obtain the following relationship:

[0089] COP=f(T temp ) (11)

[0090] In the formula, f(T temp ) is the waste water temperature of the low-temperature heat source.

[0091] 4) Establish electricity and heat demand response on the load side, considering that both electricity and heat loads have the ability of horizontal and vertical DR. Both loads can be transferred in their own time dimensions and can replace each other in the same period. Therefore, any load can be divided into three parts: fixed load, transferable load and alternative load.

[0092]

[0093] In the formula, k is the type of electrical and thermal load; is the value of the fixed load in period t; is the value of the transferable load in period t; is the value of the replaceable load in period t.

[0094] (1) Fixed load Fixed loads such as electrical and thermal loads do not participate in DR.

[0095] (2) Transferable load Transferable loads can be transferred in the time dimension within the scheduling cycle, as shown in the following formula:

[0096]

[0097] In the formula, They are the amount of transferable loads of type k load after participating in DR and the amount of transferable loads participating in DR during period t; are binary variables, representing the transfer-in and transfer-out parameters of the transferable load in the t period when the load is of type k; They are the transfer-in and transfer-out powers of the transferable load in period t when the load is of type k; They are the upper and lower limits of the DR amount of the transferable load in each period when the load is class k.

[0098] (3) Replaceable load Users can choose other energy supply methods to meet their own energy needs during the same period. For example, when electric power is in short supply, they can choose thermal power instead.

[0099]

[0100] In the formula, are the replaceable electric and thermal load values ​​after DR, respectively; Respectively represent the amount of electrical and thermal participation in replaceable electrical and thermal loads DR; They are the transfer-in and transfer-out powers of the replaceable electric and thermal load values ​​after DR in period t; They are the transfer-in and transfer-out parameters of the replaceable electric load in period t respectively; They are the transfer-in and transfer-out parameters of the replaceable heat load in period t respectively.

[0101] 5) Establish a tiered carbon trading mechanism to give full play to the dispatching value of both the source and load sides in the integrated energy system, increase the consumption rate of new energy, and reduce the system operating costs.

[0102] Figure 5 This is a carbon utilization flow chart. The electrolyzer converts H2O into two gases, H2 and O2. H2 enters the next stage and is transported to the methane reactor to synthesize natural gas with CO2 to supply CHP and GB. At the same time, the CO2 generated by the waste incineration power plant can be captured by the carbon capture field and then transferred to the MR reaction in the previous stage. The step-type carbon trading mechanism guides this process. This cycle can effectively reduce carbon emissions and energy recycling. The specific conversion model can be described as follows.

[0103] (1) EL equipment

[0104]

[0105] Where P EL,H2 (t) is the hydrogen power output by EL at time t; P e,EL (t) is the electric power input to EL at time t; are the maximum and minimum values ​​of the input EL electric power respectively; are the maximum and minimum climbing power of EL respectively; η EL is the energy conversion efficiency of the EL process.

[0106] (2) MR equipment

[0107]

[0108] Where P MR,g (t) is the natural gas power output by MR at time t; is the input hydrogen power of MR at time t; are the maximum and minimum values ​​of the input hydrogen power of MR respectively; are the maximum and minimum values ​​of MR climbing power respectively; η MR , β MR They are the conversion efficiency of natural gas and thermal energy in the MR process respectively. It is known that for every 1 kWh of electricity consumed to generate hydrogen for reaction, the recoverable methanation reaction heat is 0.1188 kWh.

[0109] (3)CCS equipment

[0110] The energy consumption of the carbon capture system is the energy consumption of system operation It can be expressed as:

[0111]

[0112] Where, σ is the energy consumption coefficient required to capture unit CO2; is the mass of CO2 processed by the CCS system at time t.

[0113] The operating power constraint of the carbon capture system at time t is:

[0114]

[0115] Where P CCS (t) is the operating energy consumption of the carbon capture device at time t; It is the maximum operating energy consumption of the carbon capture device at time t.

[0116] (4) Ladder-type carbon trading mechanism model

[0117] Under the carbon trading mechanism, carbon emissions can be freely bought and sold free of charge. The allocation of free carbon emissions is shown below.

[0118]

[0119] In the formula, E IES 、E e,buy 、E CHP 、E GB 、E WI They are the free carbon emission quotas of the integrated energy system, external power purchase, CHP system, GB and waste incineration power plant; β e , β h , β w are the free carbon emission coefficients of electricity purchased from the external grid, heat generated by GB, and electricity generated by the waste incineration power plant; P e,buy (t) is the system's purchased power at time t; P CHP (t), H CHP (t) are the output power of electric energy and thermal energy of CHP at time t; H GB (t) is the output thermal power of the gas boiler at time t; φ e,h It is the equivalent heat conversion factor of the power generation of CHP equipment.

[0120] Since the P2G and CCS processes consume CO2, the actual carbon emissions of IES are:

[0121]

[0122] In the formula, They are the actual carbon emissions of the integrated energy system, external power purchase, CHP system, GB, and waste incineration power plant; is the carbon absorption capacity of P2G; β g , β c They are the actual carbon emission coefficients of P2G and CCS respectively.

[0123] The present invention calculates the carbon trading cost based on the tiered pricing mechanism. Tiered carbon emission trading cost The calculation is as follows:

[0124]

[0125] In the formula, α is the carbon trading price growth coefficient; c is the carbon trading base price; d is the length of the carbon trading price range; ΔE is the difference between the actual carbon emissions of the integrated energy system and the free carbon emission quota.

[0126] The carbon trading volume ΔE in the tiered carbon emission trading cost is:

[0127]

[0128] 6) Construct objective function and constraints

[0129] The present invention aims to minimize the IES low-carbon economic operation cost, and constructs the objective function as follows:

[0130]

[0131] Where, F is the IES low-carbon economic operation cost; They are electricity purchase cost, gas purchase cost, waste incineration power plant cost, tiered carbon trading cost, demand-side response compensation cost, P2G cost, and wind curtailment cost.

[0132] (1) Electricity purchase cost

[0133]

[0134] Where P e,buy (t) is the amount of electricity purchased at time t; α t is the electricity price at time t.

[0135] (2) Gas purchase cost

[0136]

[0137] Where P g,buy (t) is the gas purchase volume at time t; G P2G is the amount of natural gas produced by P2G at time t; β t is the gas price at time t.

[0138] (3) Demand-side response compensation costs

[0139]

[0140] (4) P2G costs

[0141] The cost of P2G is mainly raw material cost and operation cost:

[0142]

[0143] Q buy =Q P2G,sum -Q P2G (28)

[0144] In the formula, is the price of purchasing CO2; Q buy is the amount of CO2 purchased; k P2G is the P2G operation cost coefficient; Q P2G,sum is the total CO2 consumption; Q P2G is the amount of CO2 obtained by P2G.

[0145] (5) Wind curtailment costs

[0146]

[0147] In the formula, δ DG is the unit wind abandonment penalty coefficient; P DG,cut (t) is the wind power abandoned at time t.

[0148] (6) Waste incineration power plants have no fuel costs and only need to calculate the cost of participating in carbon trading.

[0149] The constraints are as follows:

[0150] (1) Wind power output constraints

[0151]

[0152] Where P DG (t) is the wind power output at time t; is the maximum wind power at time t.

[0153] (2) Operation constraints of electric and thermal energy storage

[0154]

[0155] Where P ESC,max , P ESD,max are the maximum values ​​of charge and discharge power respectively; They are whether the electrical and thermal energy storage devices are charging and discharging, or whether they are energizing and discharging, respectively, in period t, if yes, it is 1, if no, it is 0; S ES,max , S ES,min are the maximum and minimum values ​​of the storage capacity respectively; are the beginning and end values ​​of the electric energy storage at one day. The constraints of thermal energy storage are the same as those of electric energy storage, so they will not be described in detail.

[0156] (3) Electric power balance constraints

[0157]

[0158] Where P e,Load (t) is the electric load after the demand side responds at time t; is the maximum value of the purchased power at each moment; is the power input into the energy storage at time t.

[0159] (4) Thermal power balance constraints

[0160]

[0161] Where P h,Load (t) is the heat load at time t; It is the waste heat recovered by the waste heat recovery device; is the power input into the thermal energy storage at time t.

[0162] (5) Gas power balance constraints

[0163] P g,buy (t) = P g,Load (t)+P g,CHP (t)+P g,GB (t)-P MR，g (t) (35)

[0164] Where P g,Load (t) is the gas load at time t.

[0165] The method of the present invention is simulated and applied. Figure 6 It is the load and wind power output prediction in the system. In order to verify the effectiveness of the optimization model proposed in the present invention, 24 hours a day is used as a cycle for verification. The time-of-use electricity price is shown in Table 1, and other equipment parameters are shown in Table 2.

[0166] Table 1 Time-of-use electricity price

[0167]

[0168] Table 2 Other equipment parameters

[0169]

[0170] In order to verify the advantages of the energy supply side response, combined with the electricity-heat demand side response and carbon cycle mechanism composed of the cogeneration unit equipped with ORC and the gas boiler equipped with waste heat recovery device described in the present invention, the present invention constructs 5 operating modes, as shown in Table 3, all of which adopt the step-by-step carbon trading model. Table 4 is the cost result analysis under the 5 operating modes.

[0171] Table 3 Four operating modes

[0172]

[0173] Table 4 Comparison of costs of five operating modes

[0174]

[0175]

[0176] Figure 7 It is the mode 1 electric load and the output of each power supply unit. During the nighttime period of 21:00-24:00 and the early morning period of 0:00-7:00, the electricity price and the electric load are at a low period, the thermal load remains at a peak period, and the wind power continues to increase and reaches a peak value. Due to a large amount of wind power generation, there is not enough load at the load end to balance it, and the waste incineration power plant has a minimum power output limit, resulting in a large amount of wind abandonment.

[0177] Figure 8 It is the flexible response on the electricity-heat demand side of Mode 2. Compared with Mode 1, Mode 2 adds flexible response on the electricity-heat demand side. Since wind power has a strong anti-peak characteristic, in order to consume wind power locally as much as possible, under the influence of real-time electricity prices, the electricity load shifts the load demand from 11:00-13:00 at noon and 17:00-19:00 in the evening to the night; while the demand for thermal load is higher at night and lower during the day.

[0178] Fig. 9 The power load and output of each power supply unit in mode 3. The cogeneration unit will generate a lot of heat when supplying high power in the evening from 18:00 to 21:00. Therefore, the system chooses to transfer part of the heat load demand at night to the daytime and evening. The system actively guides users to participate in the IDR strategy through incentive compensation and smoothes the user curve. Combined with Table 3, it can be seen that although mode 3 increases part of the demand response cost, the penalty cost for wind abandonment is reduced by 871.4 yuan. In addition, due to the transfer and replacement of part of the power load during the peak period of 11:00-19:00, the amount of electricity purchased from the external network and the high carbon emissions it brings are reduced, reducing the total cost by 9.6%.

[0179] Fig.10It is the heat load of modes 3 and 4 and the output of each heating unit. In the early morning period of 0:00-7:00, the electricity load demand is at a low point and the heat load demand is at a peak. The heat output of CHP in modes 4 and 3 is supplied by waste heat boilers. In the period of 10:00-20:00 when the electricity load is high and the heat load is low, a part of the thermal power generated in the CHP is supplied to the ORC for waste heat power generation, which reduces the high amount of electricity purchased from the external network during the peak period of electricity load and the high carbon emissions it generates, and utilizes the thermal energy generated by CHP in mode 3 due to the "heat-to-electricity" policy, thereby improving energy efficiency.

[0180] Fig.11 It represents the diversion of high-temperature flue gas. Mode 4 adds a water source heat pump, a spray tower, and a waste heat recovery device on the basis of Mode 3. It takes into account the recovery of heat energy from the methanation reaction and the utilization of high-temperature flue gas discharged from waste incineration power plants and gas boilers. During the peak period of wind power output, not only does the power-to-gas equipment actively absorb wind power, but the water source heat pump flexibly consumes a small amount of electricity during the non-electricity-intensive periods of 21:00-24:00 and 0:00-7:00 to extract heat from the high-temperature flue gas and provide it to the heating network.

[0181] Fig.12 Mode 5 refers to the electrical load and the output of each power supply unit. Compared with Mode 4, which only allows "heat for electricity" when the electricity is sufficient, Mode 5 supplements "electricity for heat" when the electricity is sufficient. In addition, Mode 5 adds a CO2 capture device on the basis of Mode 4, improves the electrical and thermal response of the energy supply side, and makes the system scheduling more flexible.

[0182] Fig.13 It represents the CO2 emission and capture amount. CO2 is captured during periods of low electricity load and high wind power to increase the new energy consumption rate. The separated CO2 can be supplied to the methanation reaction device, which not only reduces carbon emissions, but also reduces the carbon purchase cost and realizes the carbon cycle. The tiered carbon trading cost of Mode 4 has been greatly reduced, which is 1,214.1 yuan less than that of Mode 1.

[0183] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An optimal dispatching method for an integrated energy system including a waste incineration power plant considering demand response is characterized by: The following steps are included: Step 1: Construct an IES physical model including a waste incineration power plant that takes into account the response on both the supply and demand sides; Step 2: Construct an operation model of a CHP unit after introducing an organic Rankine cycle (ORC). The heat output of the CHP unit after introducing ORC includes two flow modes, namely, supplying heat load through a waste heat boiler (WHB) and generating electricity through waste heat through ORC. Step 3: Construct a waste incineration-flue gas treatment-waste heat recovery system operation model. Add a waste heat recovery device on the basis of the traditional flue gas treatment and purification device to recover the waste heat in the flue gas and reduce CO2 emissions. When the electrical energy is greater than the thermal energy, recover the heat of the emitted flue gas and perform an electric heating response on the energy supply side. Step 4: Establish an electric and thermal load demand response model on the load side. The electric and thermal loads are transferred in their respective time dimensions and replace each other in the same period. Any load consists of three parts: fixed load, transferable load and alternative load. Step 5: Establish a ladder carbon trading mechanism model. The electrolyzer converts H2O into two gases, H2 and O2. H2 enters the next stage and is transported to the methane reactor to synthesize natural gas with CO2. It can be supplied to the cogeneration and gas boiler GB to give full play to the dispatching value of both the source and the load in the comprehensive energy system, improve the consumption rate of new energy, and reduce the operating cost of the system. Step 6: With the goal of minimizing the low-carbon economic operation cost of the integrated energy system IES, construct the objective function and constraints, and formulate a scheduling strategy.

2. The method for optimizing the dispatch of an integrated energy system including a waste incineration power plant taking into account demand response according to claim 1 is characterized by: The IES physical models described in step 1 are as follows: the energy supply side includes the power grid, natural gas market, wind turbines and waste incineration power plants; the coupling equipment part includes electrolyzers, methanation reaction equipment, gas boilers and ORC waste heat power generation devices; the terminal energy consumption part includes electrical loads and thermal loads.

3. The method for optimizing the dispatch of an integrated energy system including a waste incineration power plant taking into account demand response according to claim 1 is characterized by: The operation model of the CHP unit after the introduction of ORC in step 2 is: In the formula, is the thermal power of ORC waste heat recovery in the CHP unit; is the thermal power output by WHB; is the power generation of ORC waste heat recovery; η ORC is the electric-to-thermal conversion efficiency of ORC; and They are The minimum and maximum values ​​of and They are The upper and lower limits of the climbing rate, is the thermal power output of the CHP unit.

4. The method for optimizing the dispatch of an integrated energy system including a waste incineration power plant taking into account demand response according to claim 1 is characterized by: The operation model of the waste incineration-flue gas treatment-waste heat recovery system described in step 3 is expressed by the gas boiler GB model as follows: Where P GB,h (t) is the thermal power output of GB unit; P g,GB (t) is the input GB gas power; η GB is the efficiency of input GB during period t; They are the maximum and minimum climbing values ​​of GB respectively; are the maximum and minimum values ​​of the input gas power respectively.

5. The method for optimizing the dispatch of an integrated energy system including a waste incineration power plant considering demand response according to claim 1 is characterized by: The electric heating load demand response model described in step 4 is: In the formula, k is the type of electrical and thermal load; is the value of the fixed load in period t; is the value of the transferable load in period t; is the value of the replaceable load in period t.

6. The method for optimizing the dispatch of an integrated energy system including a waste incineration power plant considering demand response according to claim 1 is characterized by: The ladder carbon trading mechanism model described in step 5 is: Under the carbon trading mechanism, carbon emissions are traded free of charge, and the free carbon emissions quota is allocated as follows: In the formula, E IES 、E e,buy 、E CHP 、E GB 、E WI They are the free carbon emission quotas of the integrated energy system, external power purchase, CHP system, GB and waste incineration power plant; β e , β h , β w are the free carbon emission coefficients of electricity purchased from the external grid, heat generated by GB, and electricity generated by the waste incineration power plant; P e,buy (t) is the system's purchased power at time t; P CHP (t), H CHP (t) are the output power of electric energy and thermal energy of CHP at time t; H GB (t) is the output thermal power of the gas boiler at time t; φ e,h is the equivalent heat conversion factor of the CHP equipment power generation, P WI (t) is the output power of the waste incineration power plant at time t; The actual carbon emissions of IES are: In the formula, They are the actual carbon emissions of the integrated energy system, external power purchase, CHP system, GB, and waste incineration power plant; is the carbon absorption capacity of P2G; β g , β c are the actual carbon emission coefficients of P2G and CCS, P P2G (t), P CCS (t) are the energy consumption of P2G equipment and carbon capture equipment, respectively. The tiered pricing mechanism is used to calculate the carbon trading costs. The calculation formula is: In the formula, α is the carbon trading price growth coefficient; c is the carbon trading base price; d is the length of the carbon trading price range; ΔE is the difference between the actual carbon emissions of the integrated energy system and the free carbon emission quota; The carbon trading volume ΔE in the tiered carbon emission trading cost is:

7. The method for optimizing the dispatch of an integrated energy system including a waste incineration power plant considering demand response according to claim 1 is characterized by: The objective function in step 6 is: Where, F is the IES low-carbon economic operation cost; They are electricity purchase cost, gas purchase cost, waste incineration power plant cost, tiered carbon trading cost, demand-side response compensation cost, P2G cost, and wind curtailment cost.

8. The method for optimizing the dispatch of an integrated energy system including a waste incineration power plant taking into account demand response according to claim 1 is characterized by: The constraints described in step six include wind power output constraints, electric and thermal energy storage operation constraints, electric power balance constraints, thermal power balance constraints and gas power balance constraints.

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