A low-carbon scheduling method for rural chemical industrial park comprehensive energy system based on electrotransamination and biomass waste energy conversion

Abstract

The application discloses a kind of based on electric conversion ammonia and biomass energy conversion rural chemical industry park comprehensive energy system low-carbon scheduling method, belong to electric power system technical field.Carbon-ammonia coupling process is considered, ammonia gas produced by electric conversion ammonia is matched with carbon capture equipment, and biomass energy conversion is introduced to construct chemical industry park combined production unit.Through to rural chemical industry park comprehensive energy system modeling, chemical industry park flexibility response modeling is carried out, and the operation mode of combined production unit is analyzed, and the low-carbon economic dispatching model of chemical industry park is established.The low-carbon scheduling method of rural chemical industry park comprehensive energy system based on electric conversion ammonia and biomass energy conversion of the application can realize green chemical production, reduce the carbon emission of park, effectively improve the economy of system, greatly promote energy cascade utilization, and realize low-carbon economic dispatching.

Description

Technical Field

[0001] This invention belongs to the field of power system technology, and in particular relates to a low-carbon dispatching method for a comprehensive energy system in rural chemical industrial parks based on electro-ammonia conversion and biomass waste energy conversion. Background Technology

[0002] With the implementation of the national strategy to promote rural revitalization, a large number of chemical enterprises have relocated from cities to rural areas. However, the entry of chemical production, mainly based on coal-fired and gas-fired units, into rural areas has brought serious environmental pollution, resulting in high carbon emissions and waste of resources.

[0003] Power-to-ammonia (P2A) technology can utilize surplus renewable resources to produce ammonia, and is one of the important technological routes for achieving low-carbon economic development in rural chemical industrial parks. Ammonia, as a basic raw material for chemical production, can be used to produce urea for agricultural production.

[0004] Compared to traditional chemical industrial parks, rural chemical industrial parks have relatively mature technology for biomass power generation, which uses straw and domestic waste as the main energy sources. Biomass waste energy conversion (BWEC) can convert biomass into other energy sources to meet system needs while reducing pollution in the park. In addition, there are many flexible resources within the park that are not being effectively utilized.

[0005] It is evident that the current park integrated energy system (PIES) in rural chemical industrial parks has a large proportion of distributed resources, complex multi-energy coupling relationships, and increased operational difficulty. Therefore, optimizing the park's energy structure, reducing carbon emissions and pollution, achieving energy cascade utilization, and improving system economics are of great significance for realizing the sustainable development of rural integrated energy systems.

[0006] Therefore, there is an urgent need for a new technical solution to address this problem. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a low-carbon scheduling method for the integrated energy system of rural chemical industrial parks based on electro-ammonia conversion and biomass waste energy conversion, in order to solve the technical problems of unoptimized energy system structure, high carbon emissions, and energy waste in existing technologies for rural chemical industrial parks.

[0008] The technical solution adopted in this invention is to provide a low-carbon dispatching method for a comprehensive energy system in rural chemical industrial parks based on electro-ammonia conversion and biomass waste energy conversion, comprising the following steps:

[0009] Step 1: Modeling the Integrated Energy System of a Rural Chemical Industrial Park

[0010] (1) Energy flow relationship of the park's integrated energy system

[0011] The integrated energy system of the rural chemical industrial park is powered by the upper-level power grid, the upper-level gas grid and the biomass waste energy conversion unit. The energy input on the source side meets the load demand through the internal coupling equipment of the system. Organic Rankine cycle waste heat power generation is introduced on the source side. Part of the heat power generated by the gas turbine is supplied to the heat load through the waste heat boiler, and the other part is supplied to the electrical load through the organic Rankine cycle waste heat power generation, realizing the heat and power flexibility of cogeneration. The comprehensive demand response of multiple energy loads is considered on the load side, further increasing the system flexibility.

[0012] (2) Refined modeling of the two-stage electro-ammonia conversion

[0013] ① The first stage involves hydrogen production through water electrolysis and nitrogen production through pressure swing adsorption (PSA). The heat generated during water electrolysis in the electrolyzer is supplied to the heat load. The electrolyzer model is as follows:

[0014]

[0015] In the formula: P EC (t), P EC,h (t) represents the output power and thermal power of the electrolytic cell during time period t; P ECr Rated power; η EC η EC,h ... These are the maximum and minimum input power of the electrolytic cell;

[0016] Fluctuations in wind and solar power generation lead to inconsistent hydrogen production at different times. Adding a hydrogen storage tank allows for smooth regulation of hydrogen production, reducing the adjustment pressure on ammonia production equipment.

[0017]

[0018] In the formula: This refers to the capacity of the hydrogen storage tank. For the hydrogen storage and utilization power during time period t; η cha η dis For hydrogen storage and utilization efficiency; These are the maximum and minimum capacities of the hydrogen storage tank, respectively.

[0019] Part of the electricity generated by wind and solar power is sent to a pressure swing adsorption (PSA) unit to separate nitrogen and oxygen.

[0020]

[0021] In the formula: P PSA(t) represents the PSA input power during time period t; m air (t) represents the mass flow rate of air during time period t; P represents the input and output pressures; T PSA Operating temperature; η m η is,PSA These are the compressor's mechanical efficiency and isentropic efficiency, respectively.

[0022] ② The second stage is the synthesis of ammonia from hydrogen and nitrogen. The heat generated in the ammonia production process is utilized to meet the heat load requirements. The ammonia production equipment model is processed as follows:

[0023]

[0024] In the formula: The thermal power provided to the ammonia production equipment during time period t; Input and output power of the ammonia generator during time period t; For ammonia production efficiency; η P2A The heat release ratio for heating the ammonia production equipment; σ is the heat power released per unit mass of ammonia gas. The mass of ammonia generated during time period t; These are the maximum and minimum input power of the ammonia production equipment, respectively.

[0025] (3) Modeling of urea synthesis unit

[0026] Considering the carbon-ammonia coupling process in urea synthesis, carbon capture equipment is introduced to absorb and utilize the carbon dioxide produced by the gas turbine units and waste incineration units, reducing carbon purchase costs and lowering the park's carbon emissions.

[0027]

[0028] In the formula: P CC (t) represents the energy consumption of the carbon capture equipment during time period t; V CC (t), V CS (t), These represent the volumes of carbon dioxide absorbed, stored, and utilized, respectively. These are the fixed energy consumption, maximum energy consumption, and ramp limit of the carbon capture equipment, respectively; δ CC η CC , λ CS These are the energy consumption, efficiency, and carbon dioxide sequestration efficiency per unit volume of carbon dioxide captured, respectively.

[0029] (4) Modeling of biomass waste energy conversion unit

[0030] The waste incineration plant operates in a mode with an adjustable heat-to-power ratio, and its output electrothermal power is as follows:

[0031]

[0032] Where: m L (t), m dL (t), m wL (t) represents the total amount of waste and the amount of dry and wet waste during time period t; LHV w P represents the calorific value of waste incinerated per unit mass. wipp-p (t), P wipp-h (t) represents the electricity and heat generated by the waste incineration plant during time period t; η we (t), η wh (t) represents the electricity and heat generation coefficients during time period t; λ max , λ min These are the upper and lower limits of the thermoelectric ratio;

[0033] Adding flue gas treatment devices to waste incineration plants can remove gaseous pollutants generated during waste incineration.

[0034]

[0035] In the formula: Q wipp (t), P gas (t) represents the flue gas emissions and energy consumption during time period t, respectively; e gas c g These are respectively the flue gas emission intensity and the energy consumption coefficient;

[0036] In addition to adjustable heat-to-power ratios, waste incineration plants can also convert some thermal energy into electrical energy through ORC waste heat power generation, achieving thermoelectric decoupling and improving the flexibility of biomass waste energy conversion units.

[0037]

[0038] In the formula: P wipp-hh (t), P wipp-he (t) represents the heat supplied to the heat load and the heat generated by ORC waste heat power generation during time period t, respectively; P gas-h (t) represents the heat generated by the flue gas treatment device during time period t; P ORC_w (t), P ORC-we (t) represents the heat input and electricity generated by waste heat power generation during time period t; P wipp-e (t) represents the actual power generation of the waste incineration plant during time period t; η ORC η gas-h These are the waste heat power generation efficiency and the heat generation efficiency of the flue gas treatment device, respectively.

[0039] The gas produced from biomass waste is used to generate biogas through anaerobic digestion, and then purified and converted into natural gas. The biogas digester is modeled as follows:

[0040]

[0041] In the formula: R se (t), P se (t), P mg (t) represents the wastewater treatment volume, power consumption for wastewater treatment, and biogas production during time period t, respectively; η se For biogas production efficiency; λ se δ is the wastewater energy conversion coefficient. se Power consumption per unit volume of wastewater treated; ρ se The density of the wastewater;

[0042] By purifying biogas, natural gas can be supplied to the gas load, reducing the demand on the upstream gas network.

[0043] P g,was (t)=η gas P mg (t) (10)

[0044] In the formula: P g,was (t) represents the amount of natural gas produced during time period t; η gas For natural gas production efficiency;

[0045] Step 2: Flexibility Response Modeling and Joint Production Unit Operation Mode Analysis in Chemical Industrial Parks

[0046] (1) Source-side flexibility response modeling

[0047]

[0048] In the formula: η chp-e η chp-h For CHP electrical and thermal efficiency; P CHPmax P CHPmin These represent the maximum and minimum output power of CHP, respectively; ΔP CHPmax , △P CHPmin The time intervals t and t represent the maximum and minimum climbing power of CHP, respectively; P ORC,h (t), P WHB,h (t) represents the thermal power of ORC waste heat power generation and waste heat boiler during time period t; P WHB (t) represents the output thermal power of the waste heat boiler during time period t; η WHB For the thermal efficiency of the waste heat boiler; η ORC For ORC waste heat power generation efficiency; P ORCmax P ORCmin These represent the maximum and minimum output power of ORC waste heat power generation during time period t; ΔP ORCmax , △P ORCmin The maximum and minimum ramping power of ORC waste heat power generation are, in order, time period t;

[0049] (2) Load-side integrated demand response modeling

[0050] PIES contains various types of loads, consisting of three parts: fixed, reduced, and substitute. Load reduction and substitution between different load types are considered.

[0051]

[0052] In the formula: i represents the load type; P i,load (t) represents the value of the i-th type of load in time period t; For the fixed load of type i in time period t; For time period t, the load reduction type of the i-th load; For time period t, the alternative load for the i-th type of load;

[0053]

[0054] In the formula: These represent the load value after demand response and the value participating in demand response for the i-th type of reduced / substituted load during time period t, respectively. For the parameters of the i-th type of alternative load transferred in and out during time period t; The transfer-in and transfer-out amounts for the i-th type of alternative load during time period t are, in order. These are the minimum and maximum values ​​of the i-th type of load reduction / substitution during time period t, respectively;

[0055] (3) Analysis of the operation mode of the joint production unit in the chemical industrial park

[0056] Considering the carbon-ammonia coupling process in urea synthesis, carbon capture is introduced to construct a CCS-P2A chemical production unit.

[0057]

[0058] In the formula: P P2A (t), P CCS (t) represents the power supplied to P2A and CCS during time period t; P wind (t), P pv (t) represents the power supplied to chemical production by wind power and photovoltaic power respectively during time period t; P e (t), P h (t) represents the power of the electrical and thermal load supplied to the chemical production unit during time period t; P wind,e (t), P pv,e (t) represents the power of wind power and photovoltaic power transmitted into the system during time period t;

[0059] In the context of rural areas, a biomass waste energy conversion unit was introduced to construct a CCS-P2A-BWEC joint production unit, establishing a multi-energy synergy relationship and simultaneously analyzing its electrical, thermal, gas, and carbon energy coupling characteristics.

[0060]

[0061] In the formula: P f (t), P BWEC (t) represents the electricity purchased from the upstream power grid and the additional load power supplied during time period t; P CHP,g (t), P GB,g (t) represents the amount of natural gas supplied to BWEC for CHP and GB during time period t; P J,h (t) represents the total heat production of the combined production unit during time period t; P CHP,hh (t), P GB,hh (t) represents the heat generated by CHP and GB after gas supply during time period t; P B,h (t), P P2A,h (t) represents the heat generated by BWEC and P2A during time period t;

[0062] Step 3: Low-carbon economic scheduling model for chemical industrial parks

[0063] (1) Objective function

[0064] With the goal of optimizing the operating cost of the park's integrated energy system, and without considering power transmission to the upper-level grid, surplus wind and solar power are absorbed through P2A (Power-to-Average) integration. The objective function is as follows:

[0065]

[0066] Where: T is the scheduling period; C is the total operating cost within the PIES scheduling period; C E (t) represents the system's electricity purchase cost during time period t; C Q (t) represents the system gas purchase cost during time period t; C M (t) represents the system operation and maintenance cost for time period t; C D (t) represents the system demand response cost during time period t; C C (t) represents the system carbon trading cost for period t; C N (t) represents the system's chemical profit during time period t; C B (t) represents the ecological benefits during time period t;

[0067] ① System energy purchase cost

[0068] Energy purchase costs include electricity purchase costs and gas purchase costs.

[0069]

[0070] In the formula: α(t) and β(t) represent the time-of-use electricity price and the fixed gas price for time period t, respectively; P e,buy (t), P g,buy (t) represents the amount of electricity and natural gas purchased from the upstream network during time period t;

[0071] ②Operating and maintenance costs

[0072]

[0073] In the formula: P agas (t), P UR (t) represents the ammonia and urea production during time period t; P EB,h (t) represents the heat generated by EB during time period t; P ER,c (t), P AC,c (t) represents the cooling output of ER and AC during time period t; P edis (t), P hdis (t), P cdis (t), P Hdis (t) represents the energy released by electrical, thermal, cold, and hydrogen storage during time period t;

[0074] ③ Demand response cost

[0075]

[0076] In the formula: k represents the load type; λ i For various load compensation coefficients;

[0077] ④ Carbon trading costs

[0078] The initial carbon quota model is as follows:

[0079]

[0080] In the formula: E PIES E e,buy E CHP E GB and E was The carbon emission allowances are, in order, PIES, the upstream power grid, CHP, GB, and the waste incineration plant; λ represents the carbon emission allowance per unit of power.

[0081] Based on the characteristics of biomass power generation, straw participates in a carbon cycle. Ignoring carbon emissions from straw combustion, the actual carbon emission model is as follows:

[0082]

[0083] In the formula: E PIES,a E e,buy,a E CHP,a E GB,a and E was,a This represents the actual carbon emissions from PIES, the upstream power grid, CHP, GB, and waste incineration plants; δ i These represent the actual carbon emissions per unit of power;

[0084] The PIES' participation volume and carbon trading costs are as follows:

[0085]

[0086] In the formula: E C The amount of carbon emissions used to participate in the carbon trading market; λ represents the carbon trading price;

[0087] ⑤ Chemical industry profits

[0088]

[0089] In the formula: C Nsell (t), C Ntran (t), The following are, in order: profit from selling urea during time period t, transportation costs, and the quality of urea produced; C tran This includes the selling price and transportation cost per unit mass of urea.

[0090] ⑥ Ecological benefits

[0091] The ecological benefits include subsidies for biomass waste energy conversion, which reduce the environmental pollution control costs caused by waste incineration.

[0092]

[0093] In the formula: C W (t), C e (t) represents the biomass waste energy conversion subsidy and environmental cost for time period t, respectively. G C se Subsidies for waste and wastewater treatment by the unit, where I represents the type of pollutant; K represents the tax payable based on the pollutant equivalent; m i η represents the quantity of the i-th pollutant generated when a unit of garbage or straw is burned; i The efficiency of flue gas treatment devices and environmental protection devices in removing the i-th pollutant; G i Let be the pollution equivalent number of the i-th pollutant;

[0094] (2) Constraints

[0095] ① Power balance constraints

[0096]

[0097]

[0098] P g,load (t)=P g,buy (t)+P g,was (t)-P CHP (t)+P GB (t) (27)

[0099] P c,load (t)=P ER,c (t)+PAC,c (t)+P cdis (t)-P ccha (t) (28)

[0100] In the formula: P W (t), P PV (t) represents the wind power and solar power output during time period t, respectively; P EB (t), P ER (t) represents the power consumption of EB and ER during time period t; P AC (t) represents the heat consumption of AC during time period t; P echa (t), P hcha (t), P ccha (t) represents the stored energy of electricity, heat, and cold energy during time period t;

[0101] ②Constraints of biomass waste energy conversion units

[0102]

[0103] Where: m L,max m L,min These represent the upper and lower limits for waste treatment by the biomass waste energy conversion unit; R se,max R se,min These represent the upper and lower limits for wastewater treatment by the biomass waste energy conversion unit, respectively; △P mg,max , △P mg,min The maximum and minimum climbing power for biogas production rate; Δm L,max , △m L,min The maximum and minimum ramp power for the biomass waste energy conversion unit to process waste.

[0104] Through the above design scheme, the present invention can bring the following beneficial effects:

[0105] 1. Considering the carbon-ammonia coupling process, the ammonia gas generated from the electro-ammonia conversion is combined with carbon capture equipment to achieve green chemical production, reduce carbon emissions in the industrial park, and improve the system's economic efficiency. Simultaneously, the heat generated during the electro-ammonia conversion process is utilized, promoting the cascade utilization of energy.

[0106] 2. Compared to traditional chemical industrial parks, this patent introduces biomass waste energy conversion to construct integrated production units within the park, improving its energy structure. Biomass energy serves as a flexible resource to optimize park scheduling. Through the biomass waste energy conversion unit, the total system cost is reduced while carbon emissions decrease, achieving low-carbon economic scheduling.

[0107] 3. By introducing ORC waste heat power generation on the source side and integrated demand response on the load side, source-load coordinated and optimized scheduling is achieved, maximizing the system's regulation capacity. This reduces carbon emissions in the industrial park and lowers the overall system cost. This demonstrates the significant importance of the method proposed in this patent for achieving low-carbon development of integrated energy systems for rural chemical industries. Attached Figure Description

[0108] Figure 1 This is a schematic diagram of the energy flow of the integrated energy system in a rural chemical industrial park, based on a low-carbon dispatching method for an integrated energy system of a rural chemical industrial park using electro-ammonia conversion and biomass waste energy conversion, according to the present invention.

[0109] Figure 2 This is a schematic diagram of the two-stage production structure of ammonia conversion based on a low-carbon scheduling method for a comprehensive energy system in a rural chemical industrial park according to the present invention, which is based on ammonia conversion and biomass waste energy conversion.

[0110] Figure 3 This is a schematic diagram of the biomass waste energy conversion unit structure in a low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion, according to the present invention.

[0111] Figure 4 This is a schematic diagram of the CCS-P2A-BWEC joint production unit operation framework for a low-carbon scheduling method of a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion, according to the present invention.

[0112] Figure 5 This is a schematic diagram showing the comparison results of scenario 1 and 2 of the low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion according to the present invention.

[0113] Figure 6 This is a schematic diagram of the power balance of electricity and heat in scenario 3 of the low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion, according to the present invention.

[0114] Figure 7 This is a schematic diagram of the demand response results in scenario 5 of the low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion, according to the present invention.

[0115] Figure 8 This is a schematic diagram of the power balance of electricity, heat, and gas in scenario 6 of the present invention, which describes a low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion.

[0116] Figure 9 This is a schematic diagram illustrating the carbon trading price analysis of a low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion, according to the present invention.

[0117] Figure 10This is a schematic diagram illustrating the urea price analysis of a low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion, as proposed in this invention. Detailed Implementation

[0118] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0119] This invention proposes a low-carbon dispatching method for a comprehensive energy system in rural chemical industrial parks based on electro-ammonia conversion and biomass waste energy conversion, comprising the following steps:

[0120] Step 1: Modeling of Rural Chemical Integrated Energy System

[0121] 1. Energy flow relationship of the park's integrated energy system

[0122] Energy flow diagram of integrated energy system in rural chemical industrial park as follows Figure 1 As shown, PIES is powered by the upstream power grid, upstream gas grid, and biomass waste energy conversion unit. Energy input from the source side meets load demand through internal coupling equipment. System coupling equipment includes gas boilers (GB), gas turbines (GT), waste heat boilers (WHB), electric boilers (EB), organic Rankine cycle (ORC) waste heat power generation, electric refrigerators (ER), and absorption chillers (AC). Energy storage equipment includes electrochemical energy storage, thermal storage tanks, cold storage tanks, and hydrogen storage tanks. Furthermore, ORC waste heat power generation is introduced on the source side, supplying part of the heat power generated by the gas turbine to the thermal load through WHB, and the other part to the electrical load through ORC waste heat power generation, achieving the thermoelectric flexibility of combined heat and power (CHP). Considering the comprehensive demand response of multiple energy loads on the load side further increases system flexibility.

[0123] 2. Refined Modeling of Two-Stage Electro-Ammonia Conversion

[0124] With the large-scale grid connection of distributed energy resources, P2A (Power-to-Ammonia) has become an important technology for chemical industrial parks to utilize wind and solar power and achieve green ammonia production. This invention divides P2A into two stages: the first stage involves hydrogen production via water electrolysis and nitrogen production via pressure swing adsorption (PSA); the second stage involves the synthesis of ammonia from hydrogen and nitrogen. The two-stage electro-ammonia conversion structure is as follows: Figure 2 As shown.

[0125] Electrolysis of water is an important method for producing green hydrogen, as it generates oxygen and hydrogen from water through electrolysis. In practice, the voltage applied to the electrolyzer is higher than the ideal voltage, generating heat that needs to be removed by cooling the electrolyte, resulting in heat loss. This invention provides the heat generated during the water electrolysis process to the heat load. The electrolyzer model is as follows:

[0126]

[0127] In the formula: P EC (t), P EC,h (t) represents the output power and thermal power of the electrolytic cell during time period t; P ECr Rated power; η EC η EC,h ... These are the maximum and minimum input power of the electrolytic cell.

[0128] The fluctuations in wind and solar power production lead to instability in the hydrogen produced at different times. Adding a hydrogen storage tank enables smooth regulation of the hydrogen quantity, reducing the regulation pressure on the ammonia production equipment.

[0129]

[0130] In the formula: S H2 This refers to the capacity of the hydrogen storage tank. For the hydrogen storage and utilization power during time period t; η cha η dis For hydrogen storage and utilization efficiency; These are the maximum and minimum capacities of the hydrogen storage tank, respectively.

[0131] Part of the electricity generated by wind and solar power is sent to pressure swing adsorption (PSA) equipment. PSA uses air as raw material and carbon molecular sieves as adsorbents. It is a method of separating nitrogen and oxygen by utilizing the selective adsorption of oxygen and nitrogen by carbon molecular sieves.

[0132]

[0133] In the formula: P PSA (t) represents the PSA input power during time period t; m air (t) represents the mass flow rate of air during time period t; P represents the input and output pressures; T PSA Operating temperature; η m η is,PSA These are the compressor's mechanical efficiency and isentropic efficiency, respectively.

[0134] Hydrogen produced by water electrolysis and nitrogen produced by a PSA (Pressure Suppression) unit are combined via a Haber reaction in an ammonia production unit to synthesize ammonia. The ammonia production unit consists of a compressor, heat exchanger, ammonia reactor, refrigeration system, and separation device. Nitrogen and hydrogen are mixed by the gas compressor and preheated to 400°C by the heat exchanger. The preheated mixture is then fed into the ammonia reactor where ammonia is synthesized via catalytic polymerization. The synthesized ammonia is cooled in the refrigeration system to obtain liquid ammonia. The liquid ammonia is then separated by high- and medium-pressure separators to obtain ammonia in its purest form. The purging process recycles unreacted hydrogen and nitrogen and removes inert gases accumulated in the synthesis loop. Since the ammonia conversion rate is low in a single cycle, the process needs to be repeated multiple times.

[0135] The ammonia production process is an exothermic reaction, therefore its heat can be utilized to meet heat load requirements. This patent considers the park scheduling problem and processes the ammonia production equipment model, as shown below:

[0136]

[0137] In the formula: The thermal power provided to the ammonia production equipment during time period t; Input and output power of the ammonia generator during time period t; For ammonia production efficiency; η P2A The heat release ratio for heating the ammonia production equipment; σ is the heat power released per unit mass of ammonia gas. The mass of ammonia generated during time period t; These are the maximum and minimum input power of the ammonia production equipment, respectively.

[0138] 3. Modeling of the urea synthesis unit

[0139] The synthesized ammonia is transported to a chemical synthesis unit to synthesize urea, which is then sold to local farmers for agricultural production. Considering the carbon-ammonia coupling process in urea synthesis, carbon capture equipment is introduced to absorb and utilize the carbon dioxide generated by the gas turbine unit and the waste incineration unit, reducing carbon purchase costs and lowering the park's carbon emissions.

[0140]

[0141] In the formula: P CC (t) represents the energy consumption of the carbon capture equipment during time period t; V CC (t), V CS (t), These represent the volumes of carbon dioxide absorbed, stored, and utilized, respectively. These are the fixed energy consumption, maximum energy consumption, and ramp limit of the carbon capture equipment, respectively; δ CC η CC , λ CSThese represent the energy consumption, efficiency, and carbon dioxide sequestration efficiency per unit volume of carbon dioxide captured.

[0142] 4. Modeling of Biomass Waste Energy Conversion Unit

[0143] Biomass energy technology can convert biomass energy into various energy sources to enhance the low-carbon economic characteristics of industrial parks. The biomass types studied in this patent include rural straw, as well as waste and wastewater from within the industrial park. The structure of the biomass waste-to-energy conversion unit in the park is as follows: Figure 3 As shown.

[0144] Waste treatment technologies include landfill, composting, and incineration, with incineration considered the most reliable and efficient option. As a key facility for biomass energy conversion, waste incineration plants utilize combined heat and power (CHP) to replace traditional coal-fired power plants, effectively treating waste while reducing primary energy consumption. Waste incineration plants operate in a heat-to-power ratio adjustable mode, and their output electrothermal power is as follows:

[0145]

[0146] Where: m L (t), m dL (t), m wL (t) represents the total amount of waste and the amount of dry and wet waste during time period t; LHV w P represents the calorific value of waste incinerated per unit mass. wipp-p (t), P wipp-h (t) represents the electricity and heat generated by the waste incineration plant during time period t; η we (t), η wh (t) represents the electricity and heat generation coefficients during time period t; λ max , λ min These represent the upper and lower limits of the thermoelectric ratio.

[0147] Waste in the park is collected, transported, stored, and sorted into dry and wet waste. Harmful gases produced during incineration can damage the environment; therefore, flue gas treatment devices are added to the waste incineration plant to remove gaseous pollutants generated during incineration.

[0148]

[0149] In the formula: Q wipp (t), P gas (t) represents the flue gas emissions and energy consumption during time period t, respectively; e gas c g These are the flue gas emission intensity and the energy consumption coefficient, respectively.

[0150] In addition to having an adjustable heat-to-power ratio, waste incineration plants can also convert some of the heat energy into electricity through ORC waste heat power generation, achieving heat-electric decoupling and improving the flexibility of biomass waste energy conversion units.

[0151]

[0152] In the formula: P wipp-hh (t), P wipp-he (t) represents the heat supplied to the heat load and the heat generated by ORC waste heat power generation during time period t, respectively; P gas-h (t) represents the heat generated by the flue gas treatment device during time period t; P ORC_w (t), P ORC-we (t) represents the heat input and electricity generated by waste heat power generation during time period t; P wipp-e (t) represents the actual power generation of the waste incineration plant during time period t; η ORC η gas-h These are the waste heat power generation efficiency and the heat generation efficiency of the flue gas treatment device, respectively.

[0153] Producing gas from biomass waste involves two steps: generating biogas through anaerobic digestion and then purifying the biogas into natural gas. Anaerobic digestion is a technology that converts organic matter into biogas through a series of biochemical processes in the absence of oxygen. A biogas digester is modeled as follows:

[0154]

[0155] In the formula: R se (t), P se (t), P mg (t) represents the wastewater treatment volume, power consumption for wastewater treatment, and biogas production during time period t, respectively; η se For biogas production efficiency; λ se δ is the wastewater energy conversion coefficient. se Power consumption per unit volume of wastewater treated; ρ se This refers to the density of the wastewater.

[0156] Wet waste and sewage are converted into biogas through anaerobic digestion. The biogas produced contains other impurities, which need to be removed through biogas purification technology. The purified biogas is then used to supply natural gas to the gas load, reducing the demand on the upstream gas grid.

[0157] P g,was (t)=η gas P mg (t) (10)

[0158] In the formula: P g,was (t) represents the amount of natural gas produced during time period t; η gas For natural gas production efficiency.

[0159] Step 2: Flexibility Response Modeling and Joint Production Unit Operation Mode Analysis in Chemical Industrial Parks

[0160] 1. Source-side flexibility response modeling

[0161] Traditional source-load response methods struggle to guarantee system flexibility, and the "heat-driven power generation" phenomenon in waste-to-energy plants (CHPs) makes it difficult to maintain system power balance. PIESs incorporate P2A, CHP, GB, ER, and ORC waste heat power generation equipment, enabling the coupling of multiple energy sources. During periods of low heat load, CHPs, like waste incineration plants, enhance flexibility by introducing ORC waste heat power generation into the system to convert some of the heat energy from the waste heat boiler into electricity, achieving electrothermal decoupling of CHPs and improving their flexibility. During periods of low electricity load, surplus electricity is converted into heat and cooling through P2A, EB, and ER equipment. The source-side flexibility response model is as follows:

[0162]

[0163] In the formula: η chp-e η chp-h For CHP electrical and thermal efficiency; P CHPmax P CHPmin These represent the maximum and minimum output power of CHP, respectively; ΔP CHPmax , △P CHPmin The time intervals t and t represent the maximum and minimum climbing power of CHP, respectively; P ORC,h (t), P WHB,h (t) represents the thermal power of ORC waste heat power generation and waste heat boiler during time period t; P WHB (t) represents the output thermal power of the waste heat boiler during time period t; η WHB For the thermal efficiency of the waste heat boiler; η ORC For ORC waste heat power generation efficiency; P ORCmax P ORCmin These represent the maximum and minimum output power of ORC waste heat power generation during time period t; ΔP ORCmax , △P ORCmin The values ​​represent the maximum and minimum ramping power of ORC waste heat power generation during time period t, respectively.

[0164] 2. Load-side integrated demand response modeling

[0165] Load-side integrated demand response, as an important controllable resource in PIES, can realize system energy conversion and is an important means to reduce the load peak-valley difference and promote the economical operation of the system. There are various types of loads in PIES. This invention consists of three parts: fixed, reduced, and substitute loads, taking into account load reduction and the substitution of different types of loads.

[0166]

[0167] In the formula: i represents the load type; P i,load (t) represents the value of the i-th type of load in time period t; For the fixed load of type i in time period t; For time period t, the load reduction type of the i-th load; For time period t, there is a substitute load for the i-th type of load.

[0168] For the three parts after load division, stationary loads do not participate in demand response; load shedding can be carried out during the dispatch cycle; and alternative loads can select different energy supplies to meet user demand at the same time. The load-side demand response model is as follows:

[0169]

[0170] In the formula: These represent the load value after demand response and the value participating in demand response for the i-th type of reduced / substituted load during time period t, respectively. For the parameters of the i-th type of alternative load transferred in and out during time period t; The transfer-in and transfer-out amounts for the i-th type of alternative load during time period t are, in order. These are the minimum and maximum values ​​for the i-th type of load reduction / substitution during time period t, respectively.

[0171] 3. Analysis of the Operation Mode of Joint Production Units in Chemical Industrial Parks

[0172] Urea synthesis in chemical industrial parks is affected by carbon sources. Considering the carbon-ammonia coupling process in urea synthesis, carbon capture is introduced to construct a CCS-P2A chemical production unit, which promotes chemical production in the park while reducing carbon emissions and achieving low-carbon production in the chemical industrial park.

[0173]

[0174] In the formula: P P2A (t), P CCS (t) represents the power supplied to P2A and CCS during time period t; P wind (t), P pv (t) represents the power supplied to chemical production by wind power and photovoltaic power respectively during time period t; P e (t), P h (t) represents the power of the electrical and thermal load supplied to the chemical production unit during time period t; P wind,e (t), P pv,e (t) represents the power of wind power and photovoltaic power transmitted into the system during time period t.

[0175] Based on this, and considering the rural context, a biomass waste energy conversion unit is introduced to construct a CCS-P2A-BWEC joint production unit, establishing a multi-energy synergy relationship and simultaneously analyzing its electrical, thermal, gas, and carbon energy coupling characteristics. The framework of the joint production unit in the chemical industrial park is as follows: Figure 4 As shown.

[0176] After the introduction of BWEC, BWEC can replace the upstream power grid for energy supply and supply CHP and GB by generating natural gas through the sewage treatment plant. It can flexibly participate in system scheduling, improve the energy structure of the park, enhance system flexibility, and reduce system energy purchase costs.

[0177]

[0178] In the formula: P f (t), P BWEC (t) represents the electricity purchased from the upstream power grid and the additional load power supplied during time period t; P CHP,g (t), P GB,g (t) represents the amount of natural gas supplied to BWEC for CHP and GB during time period t; P J,h (t) represents the total heat production of the combined production unit during time period t; P CHP,hh (t), P GB,hh (t) represents the heat generated by CHP and GB after gas supply during time period t; P B,h (t), P P2A,h (t) represents the heat generated by BWEC and P2A during time period t.

[0179] After constructing the CCS-P2A-BWEC joint production unit, BEWC can replace external power purchases and provide more energy, enabling more wind and solar power to generate ammonia through P2A. This increases P2A energy consumption, increases chemical production capacity, and generates more profit through the sale of urea, while reducing system costs.

[0180] From a carbon perspective, chemical production involves a carbon-ammonia coupling process. After constructing a CCS-P2A (carbon capture system-hydrogenation platform), the CO2 captured by the CCS can be used to synthesize urea, reducing the cost of purchasing CO2 from external sources while lowering carbon emissions within the industrial park. The process of purchasing electricity from the upstream power grid also generates carbon emissions. Introducing BWEC (Body-to-Energy Combined Capture) to construct a combined production unit can replace the upstream power grid, reducing the park's carbon emissions and allowing more surplus wind and solar power to pass through the P2A. The increased energy consumption of the P2A leads to increased energy consumption of the carbon capture equipment, increasing chemical production capacity and reducing overall system carbon emissions.

[0181] Furthermore, PIES possesses various flexible resources that can be integrated with ORC waste heat power generation and integrated demand response (IRT) in conjunction with the CCS-P2A-BWEC co-production unit to optimize chemical production within the industrial park. ORC waste heat power generation increases electricity supply, while IRT reduces the electricity load curve. Combined with these flexible resources, BWEC output becomes more flexible, meeting diverse load demands and enhancing system autonomy. This results in increased P2A energy consumption, increased production capacity, higher profits in chemical production, and lower system costs. From a carbon perspective, the multi-energy coupling within the system further increases P2A energy consumption, leading to increased output from carbon capture equipment and a reduction in system carbon emissions.

[0182] Step 3: Low-carbon economic scheduling model for chemical industrial parks

[0183] 1. Objective function

[0184] With the goal of optimizing the operating cost of the park's integrated energy system, and without considering power transmission to the upper-level grid, surplus wind and solar power are absorbed through P2A (Power-to-Average) integration. The objective function is as follows:

[0185]

[0186] Where: T is the scheduling period; C is the total operating cost within the PIES scheduling period; C E (t) represents the system's electricity purchase cost during time period t; C Q (t) represents the system gas purchase cost during time period t; C M (t) represents the system operation and maintenance cost for time period t; C D (t) represents the system demand response cost during time period t; C C (t) represents the system carbon trading cost for period t; C N (t) represents the system's chemical profit during time period t; C B (t) represents the ecological benefits during time period t.

[0187] 1) System energy purchase cost

[0188] Energy purchase costs include electricity purchase costs and gas purchase costs. Electricity prices are based on time-of-use pricing, while gas prices are based on fixed pricing.

[0189]

[0190] In the formula: α(t) and β(t) represent the time-of-use electricity price and the fixed gas price for time period t, respectively; P e,buy (t), P g,buy (t) represents the amount of electricity and natural gas purchased from the upstream network during time period t.

[0191] 2) Operation and maintenance costs

[0192]

[0193] In the formula: Pagas (t), P UR (t) represents the ammonia and urea production during time period t; P EB,h (t) represents the heat generated by EB during time period t; P ER,c (t), P AC,c (t) represents the cooling output of ER and AC during time period t; P edis (t), P hdis (t), P cdis (t), P Hdis (t) represents the energy released from electrical, thermal, cold, and hydrogen storage during time period t.

[0194] 3) Demand response cost

[0195]

[0196] In the formula: k represents the load type; λ i These are the compensation coefficients for various load types.

[0197] 4) Carbon trading costs

[0198] Currently, my country primarily uses a non-compensated allocation method for initial carbon allowances. The initial carbon allowance model is as follows:

[0199]

[0200] In the formula: E PIES E e,buy E CHP E GB and E was The carbon emission allowances are, in order, those for PIES, the upstream power grid, CHP, GB, and waste incineration plants; λ represents the carbon emission allowance per unit of power.

[0201] Based on the characteristics of biomass power generation, straw participates in a carbon cycle. Ignoring carbon emissions from straw combustion, the actual carbon emission model is as follows:

[0202]

[0203] In the formula: E PIES,a E e,buy,a E CHP,a E GB,a and E was,a This represents the actual carbon emissions from PIES, the upstream power grid, CHP, GB, and waste incineration plants; δ i These represent the actual carbon emissions per unit of power.

[0204] The PIES' participation volume and carbon trading costs are as follows:

[0205]

[0206] In the formula: E C λ represents the carbon emissions used to participate in the carbon trading market; λ represents the carbon trading price.

[0207] 5) Chemical industry profits

[0208]

[0209] In the formula: C Nsell (t), C Ntran (t), The following are, in order: profit from selling urea during time period t, transportation costs, and the quality of urea produced; C tran This refers to the selling price and transportation cost per unit mass of urea.

[0210] 6) Ecological benefits

[0211] Waste incineration will emit NO X Acidic gases such as SO2 are harmful to the environment. The ecological benefits include subsidies for biomass waste energy conversion, which reduce the environmental pollution control costs caused by waste incineration.

[0212]

[0213] In the formula: C W (t), C e (t) represents the biomass waste energy conversion subsidy and environmental cost during time period t, respectively. C G C se Subsidies for waste and wastewater treatment by the unit. I represents the type of pollutant; K represents the tax payable based on the pollutant equivalent; m i η represents the quantity of the i-th pollutant generated when a unit of garbage or straw is burned; i The efficiency of flue gas treatment devices and environmental protection devices in removing the i-th pollutant; G i Let be the pollution equivalent number of the i-th pollutant.

[0214] 2. Constraints

[0215] 1) Power balance constraints

[0216]

[0217]

[0218] P g,load (t)=P g,buy (t)+P g,was (t)-P CHP (t)+P GB (t) (27)

[0219] P c,load (t)=PER,c (t)+P AC,c (t)+P cdis (t)-P ccha (t) (28)

[0220] In the formula: P W (t), P PV (t) represents the wind power and solar power output during time period t, respectively; P EB (t), P ER (t) represents the power consumption of EB and ER during time period t; P AC (t) represents the heat consumption of AC during time period t; P echa (t), P hcha (t), P ccha (t) represents the stored energy of electricity, heat, and cold energy during time period t.

[0221] 2) Constraints of biomass waste energy conversion units

[0222]

[0223] Where: m L,max m L,min These represent the upper and lower limits for waste treatment by the biomass waste energy conversion unit; R se,max R se,min These represent the upper and lower limits for wastewater treatment by the biomass waste energy conversion unit, respectively; △P mg,max , △P mg,min The maximum and minimum climbing power for biogas production rate; Δm L,max , △m L,min The maximum and minimum ramp power for the biomass waste energy conversion unit to process waste.

[0224] This invention selects a rural chemical industrial park as the research object for case analysis. To verify the effectiveness of the low-carbon scheduling method proposed in this invention, the following scenarios are set up for comparative analysis:

[0225] Scenario 1, considering electro-ammonia conversion and CCS equipment.

[0226] Scenario 2 considers the two-stage operation of electro-ammonia conversion and CCS equipment, transferring the heat from the production process to the heat load.

[0227] Scenario 3 introduces BWEC based on Scenario 2 to build a joint production unit.

[0228] Scenario 4 introduces ORC waste heat power generation based on Scenario 3.

[0229] Scenario 5 introduces a comprehensive demand response based on Scenario 3.

[0230] Scenario 6 introduces a comprehensive demand response based on Scenario 4.

[0231] Simulation examples were performed for six scenarios, and the cost comparisons are shown in Table 1.

[0232] Table 1. Scheduling results under different scenarios

[0233]

[0234] In Scenario 1, the industrial park needs to maintain multi-energy load demand. When wind power is surplus at night, some energy needs to be used to generate heat through electric boilers to meet the heat load. The remaining energy is used for chemical production through P2A and carbon capture equipment, but its capacity is not high. Scenario 2 considers the two-stage operation of the electrolytic ammonia conversion process, utilizing the heat from the electrolyzer and ammonia production equipment to meet part of the heat load demand. The comparison results of Scenario 1 and 2 are as follows: Figure 5 As shown. Scenario 1, the heat load satisfied by the electric boiler can be met by the heat released from the electrolytic cell and ammonia production equipment, achieving energy cascade utilization. More energy is used for chemical production through P2A and CCS, increasing system profits. Scenario 2 shows a decrease in both carbon emissions and costs compared to Scenario 1.

[0235] Scenario 3 involves constructing a CCS-P2A-BWEC joint production unit to reduce pollution in the industrial park and promote low-carbon chemical production. Scenario 3 also includes power balance for electricity and heat. Figure 6 As shown, after introducing the biomass waste energy conversion unit, surplus wind power at night generates ammonia through P2A (Power-to-Ammonia) technology. The heat generated during ammonia production is then supplied to the heat load. During peak daytime electricity loads, the waste incineration plant implements combined heat and power (CHP), reducing external electricity purchases and GB (Power Generation) output, thus lowering system costs. After introducing BWEC (Body-to-Energy Conversion) to construct a joint production unit, the coordinated use of various resources within the park eliminates the need for external electricity purchases, enhancing the system's autonomy.

[0236] Furthermore, the wastewater treatment plant generates some natural gas from the treatment of wastewater and wet waste to meet CHP and GB requirements, further reducing the need for external gas purchases within the industrial park. After introducing BWEC, the park's carbon emissions decreased by 17.67 tons compared to Scenario 2, and the park profited from carbon trading. In the combined production unit, BWEC enables P2A to have higher energy consumption, increases urea production, and allows the system to generate greater profits in chemical production. This scenario reduces the total cost by 29,952.54 yuan compared to Scenario 2, demonstrating that introducing BWEC can optimize system scheduling.

[0237] Scenario 4 introduces ORC waste heat power generation to decouple CHP from the "heat-driven power generation" constraint and optimize the operation of the joint production unit. At night, wind power output is high, and surplus wind power meets heat load demand through P2A (Power-to-Action). During off-peak heat load periods, the "heat-driven power generation" constraint leads to insufficient CHP output. Introducing waste heat power generation converts a portion of the CHP's heat output into electricity to supply the electrical load, achieving flexible CHP output. Compared to Scenario 3, this strategy reduces cost by 9900.8 yuan and carbon emissions by 2.17 tons.

[0238] Scenario 5 introduces a comprehensive demand response based on Scenario 3. The demand response result is as follows: Figure 7 As shown, the system can achieve economic operation of the park by reducing its own energy consumption. Simultaneously, time-of-use pricing applies, as electricity load will be replaced by other loads during peak electricity price periods, reducing system costs. Under demand response, the electricity load curve decreases, and more surplus wind and solar power generate ammonia through P2A, increasing chemical profits and reducing system costs. Compared to scenario 3, this strategy reduces costs and carbon emissions by RMB 11,030.27 and 5.47 tons, respectively.

[0239] Scenario 6 introduces ORC waste heat power generation and integrated demand response to achieve source-load coordinated optimized scheduling and balance of electricity, heat, and gas power, such as... Figure 8 As shown, waste heat power generation provides partial electricity output, demand response optimizes the electricity load curve, increases BWEC flexibility, enhances park flexibility, and allows more wind and solar power to be used for chemical production via P2A, increasing P2A energy consumption. Compared to scenario 3, the system has P2A output during periods 7-9 and 20-21, resulting in increased P2A energy consumption, increased chemical profits, and reduced total system cost.

[0240] Furthermore, Scenario 6 leverages the coordinated use of various resources within the park, eliminating the need for external power purchases and enhancing the system's autonomy. ORC waste heat power generation converts some of the heat energy into electricity, reducing the need for extensive heat conversion in the BWEC, increasing heat output, and allowing more heat load to be met by the more energy-efficient GB, thus reducing carbon emissions. Therefore, compared to Scenario 3, this strategy reduces total cost by RMB 16,466.23 and carbon emissions by 7 tons.

[0241] The sensitivity analysis is shown below:

[0242] Carbon trading prices, as a weighting factor in carbon trading costs, have a certain impact on the total cost of the system due to different carbon trading prices. Carbon trading price analysis includes... Figure 9 As shown, with the increase in carbon trading prices, the weight of carbon trading prices increases, and the system's profits in carbon trading increase. Through the coupled operation of internal units, the output of high-emission units is reduced, and the system's carbon emissions continuously decrease as carbon prices rise. From a total cost perspective, as carbon trading prices increase, the system's profits in carbon trading increase, and the system's total cost continuously decreases.

[0243] Urea price is a significant factor in chemical industry profits; different urea prices will have a certain impact on the total cost of the system. Urea price analysis is as follows... Figure 10 As shown, when the urea price is below 1.1 yuan / kg, there is no profit in urea production due to transportation and maintenance costs. The surplus renewable energy source cannot generate profit through P2A (purified ammonia production), and the total system cost remains unchanged. During periods of high nighttime heat load demand, PIES (purified iron ore) supplies heat to the system via EB (purified iron ore) instead of the ammonia production equipment. When the urea price is above 1.1 yuan / kg, the weight of chemical profits within the system increases with the rise in urea price. The system adjusts to prioritize the production of ammonia from surplus renewable energy sources to generate profit, thus continuously reducing the total system cost.

[0244] The above examples are illustrative demonstrations of the proposed patent and are not intended to limit the proposed scheduling method. The rural chemical low-carbon scheduling method proposed in this patent, which considers the conversion of electricity to ammonia and biomass waste energy, has a wide range of applicability. For those skilled in the art in the field of power systems, other variations or modifications can be made based on the above description, and such variations or modifications are still within the scope of protection of this invention.

Claims

1. A low-carbon dispatching method for a comprehensive energy system in a rural chemical industrial park based on electro-ammonia conversion and biomass waste energy conversion, characterized in that: Includes the following steps: Step 1: Modeling the Integrated Energy System of a Rural Chemical Industrial Park (1) Energy flow relationship of the park's integrated energy system The integrated energy system of the rural chemical industrial park is powered by the upper-level power grid, the upper-level gas grid and the biomass waste energy conversion unit. The energy input on the source side meets the load demand through the internal coupling equipment of the system. Organic Rankine cycle waste heat power generation is introduced on the source side. Part of the heat power generated by the gas turbine is supplied to the heat load through the waste heat boiler, and the other part is supplied to the electrical load through the organic Rankine cycle waste heat power generation, realizing the heat and power flexibility of cogeneration. The comprehensive demand response of multiple energy loads is considered on the load side, further increasing the system flexibility. (2) Refined modeling of the two-stage electro-ammonia conversion The first stage involves hydrogen production via water electrolysis and nitrogen production via pressure swing adsorption (PSA). The heat generated during water electrolysis in the electrolyzer is supplied to the heat load. The electrolyzer model is as follows: (1) In the formula: , for Output power and thermal power of the time-phase electrolytic cell; Rated power; , These are the hydrogen and thermal conversion efficiencies, respectively. , , These are the efficiency function coefficients; , These are the maximum and minimum input power of the electrolytic cell; Fluctuations in wind and solar power generation lead to inconsistent hydrogen production at different times. Adding a hydrogen storage tank allows for smooth regulation of hydrogen production, reducing the adjustment pressure on ammonia production equipment. (2) In the formula: This refers to the capacity of the hydrogen storage tank. , For other Hydrogen storage and utilization power during specific time periods; , For hydrogen storage and utilization efficiency; , These are the maximum and minimum capacities of the hydrogen storage tank, respectively. Part of the electricity generated by wind and solar power is sent to a pressure swing adsorption (PSA) unit to separate nitrogen and oxygen. (3) In the formula: for PSA input power during the time period; for Mass flow rate of air during a given time period; P in , Input and output pressure; Operating temperature; , These are the compressor's mechanical efficiency and isentropic efficiency, respectively. It is the gas constant of air; The second stage involves the synthesis of ammonia from hydrogen and nitrogen. The heat generated during the ammonia production process is utilized to meet the heat load requirements. The ammonia production equipment model is shown below: (4) In the formula: for The thermal power provided by the time-phase ammonia production equipment; , for Input and output power of the ammonia generator during specific time periods; For ammonia production efficiency; The heat release ratio for heating the ammonia production equipment; The heat power released per unit mass of ammonia gas. for The mass of ammonia generated during a given period; , These are the maximum and minimum input power of the ammonia production equipment, respectively. (3) Modeling of urea synthesis unit Considering the carbon-ammonia coupling process in urea synthesis, carbon capture equipment is introduced to absorb and utilize the carbon dioxide produced by the gas turbine units and waste incineration units, reducing carbon purchase costs and lowering the park's carbon emissions. (5) In the formula: for Energy consumption of carbon capture equipment during specific time periods; , , These represent the volumes of carbon dioxide absorbed, stored, and utilized, respectively. , , These are the fixed energy consumption, maximum energy consumption, and ramp limit of the carbon capture equipment, respectively. , , These are the energy consumption, efficiency, and carbon dioxide sequestration efficiency per unit volume of carbon dioxide captured, respectively. (4) Modeling of biomass waste energy conversion unit The waste incineration plant operates in a mode with an adjustable heat-to-power ratio, and its output electrothermal power is as follows: (6) In the formula: , , for Total amount of waste during each period and the amount of dry and wet waste; This indicates the calorific value of waste incinerated per unit mass; , for Electricity and heat production of waste incineration plants during specific time periods; , for Electricity and heat generation coefficients for different time periods; , These are the upper and lower limits of the thermoelectric ratio; Adding flue gas treatment devices to waste incineration plants can remove gaseous pollutants generated during waste incineration. (7) In the formula: , They are respectively Flue gas emissions and energy consumption over a given period; , These are respectively the flue gas emission intensity and the energy consumption coefficient; In addition to adjustable heat-to-power ratios, waste incineration plants can also convert some thermal energy into electrical energy through ORC waste heat power generation, achieving thermoelectric decoupling and improving the flexibility of biomass waste energy conversion units. (8) In the formula: , They are respectively The heat supplied to the heat load during the period and the heat generated by ORC waste heat power generation; for Heat from the flue gas treatment device during a given period; , for Waste heat power generation during specific time periods inputs heat and generates electricity; for Actual power generation of waste incineration plants during specific time periods; , These are the waste heat power generation efficiency and the heat generation efficiency of the flue gas treatment device, respectively. The gas produced from biomass waste is used to generate biogas through anaerobic digestion, and then purified and converted into natural gas. The biogas digester is modeled as follows: (9) In the formula: , , They are respectively Wastewater treatment volume, electricity consumption for wastewater treatment, and biogas production per time period; For biogas production efficiency; The wastewater energy conversion coefficient; Power consumption per unit volume of wastewater treated; The density of the wastewater; By purifying biogas, natural gas can be supplied to the gas load, reducing the demand on the upstream gas network. (10) In the formula: for Natural gas production during the period; For natural gas production efficiency; Step 2: Flexibility Response Modeling and Joint Production Unit Operation Mode Analysis in Chemical Industrial Parks (1) Source-side flexibility response modeling (11) In the formula: , For CHP electrical and thermal efficiency; , These are the maximum and minimum output power of CHP, respectively. , In turn The time period is the maximum and minimum climbing power of CHP; , They are respectively Thermal power of ORC waste heat power generation and waste heat boiler during the period; for The output heat power of the waste heat boiler during the time period; For the thermal efficiency of waste heat boilers; For ORC waste heat power generation efficiency; , They are respectively Maximum and minimum output power of ORC waste heat power generation during the specified time period; , In order Maximum and minimum ramping power of ORC waste heat power generation during the specified time period; (2) Load-side integrated demand response modeling PIES contains various types of loads, consisting of three parts: fixed, reduced, and substitute. Load reduction and substitution between different load types are considered. (12) In the formula: Indicates the load type; for Time period Class load values; for Time period Fixed loads of the same type; for Time period Reduced loads of the same type; for Time period Alternative loads to similar loads; (13) In the formula: , The first Type of load reduction / alternative Load values ​​after demand response and values ​​participating in demand response during the time period; , For the first Alternative loads Time period transfer in and transfer out parameters; , The order is number 1 Alternative loads The amount transferred in and out during a given period; , The first Type of load reduction / alternative Minimum and maximum values ​​for the time period; (3) Analysis of the operation mode of the joint production unit in the chemical industrial park Considering the carbon-ammonia coupling process in urea synthesis, carbon capture is introduced to construct a CCS-P2A chemical production unit. (14) In the formula: , for The power supplied to P2A and CCS during the specified time period; , They are respectively The power supplied to chemical production by wind and solar power during certain periods; , for The power of electrical and thermal loads supplied to the chemical production unit during a given period; , They are respectively Power transmitted from wind and solar power during specific time periods; In the context of rural areas, a biomass waste energy conversion unit was introduced to construct a CCS-P2A-BWEC joint production unit, establishing a multi-energy synergy relationship and simultaneously analyzing its electrical, thermal, gas, and carbon energy coupling characteristics. (15) In the formula: , for Electricity purchased from the upstream power grid and additional load power supplied during the time period; , for BWEC supplies natural gas to CHP and GB during the specified period; for Total heat output of the combined production unit during the time period; , for Heat generated by CHP and GB after gas supply during the specified period; , They are respectively Heat generation during BWEC and P2A periods; Step 3: Low-carbon economic scheduling model for chemical industrial parks (1) Objective function With the goal of optimizing the operating cost of the park's integrated energy system, and without considering power transmission to the upper-level grid, surplus wind and solar power are absorbed through P2A (Power-to-Average) integration. The objective function is as follows: (16) In the formula: The scheduling period; This represents the total operating cost within the PIES scheduling cycle. for Time-of-use system electricity purchase cost; for Gas purchase cost for the time period system; for System maintenance costs during specific time periods; for System demand response cost during specific time periods; for Time-based carbon trading costs; for Periodic system chemical profit; for Ecological benefits over a specific period; System energy purchase cost Energy purchase costs include electricity purchase costs and gas purchase costs. (17) In the formula: , respectively Time-of-use electricity pricing and fixed gas pricing; , In order The amount of electricity and natural gas purchased from the upstream network during the specified time period; Operation and maintenance costs (18) In the formula: , for Ammonia and urea production during a given period; for Heat production by EB during the period; , They are respectively Cooling output of ER and AC during the same period; , , , for The energy released from electrical, thermal, cold, and hydrogen storage during specific time periods; , , The operating and maintenance costs are for CHP boilers, waste heat boilers, and gas-fired boilers, respectively. , The operating and maintenance costs are for absorption chillers and electric chillers, respectively. , , The maintenance and operation costs are for the electrolytic cell, ammonia production equipment, and urea synthesis equipment, respectively. , The operation and maintenance costs are for electric boilers and ORC waste heat power generation, respectively. , The operating and maintenance costs are for waste treatment plants and wastewater treatment plants, respectively. , The operation and maintenance costs are for PSA equipment and carbon capture equipment, respectively. , , , The operating and maintenance prices are for electric energy storage, thermal storage tanks, cold storage tanks, and hydrogen storage tanks, respectively. Demand response cost (19) In the formula: Load type; For various load compensation coefficients; Carbon trading costs The initial carbon quota model is as follows: (20) In the formula: , , , as well as In order, they are PIES, the upstream power grid, CHP, GB, and carbon emission allowances for waste incineration plants; These are carbon emission allowances for the upstream power grid, CHP, GB, and waste incineration plants, respectively. These are the carbon emission allowances per unit power of the upstream power grid, CHP, GB, and waste incineration plants, respectively. The unit power of the upstream power grid, CHP, GB, and waste incineration plants; Based on the characteristics of biomass power generation, straw participates in a carbon cycle. Ignoring carbon emissions from straw combustion, the actual carbon emission model is as follows: (21) In the formula: , , , and The actual carbon emissions from PIES, the upstream power grid, CHP, GB, and waste incineration plants; Indicates carbon capture amount; These are the actual carbon emissions from the upstream power grid, CHP, GB, and waste incineration plants, respectively. These are the actual carbon emissions per unit power of the upstream power grid, CHP, GB, and waste incineration plants, respectively. The PIES' participation volume and carbon trading costs are as follows: (22) In the formula: This represents the actual carbon emissions of PIES; For PIES carbon emission allowances; Carbon emissions for participating in the carbon trading market; Indicates the carbon trading price; Chemical Profits (23) In the formula: , , In order The profit margin of selling urea during a given period, transportation costs, and the quality of urea produced; , This includes the selling price and transportation cost per unit mass of urea. Ecological benefits The ecological benefits include subsidies for biomass waste energy conversion, which reduce the environmental pollution control costs caused by waste incineration. (24) In the formula: , They are respectively Subsidies and environmental costs for biomass waste energy conversion during specific periods. , Subsidies for unit waste and sewage treatment, where J represents the type of pollutant; The amount of tax payable based on the pollutant equivalent; The quantity of the j-th type of pollutant generated when a unit of garbage or straw is burned; The efficiency of flue gas treatment devices and environmental protection devices in removing the j-th pollutant; Let be the pollution equivalent number of the j-th pollutant; (2) Constraints Power balance constraints (25) In the formula: for System electrical load during specific time periods; for Electricity purchased from the superior power grid during the specified time period; , They are respectively Wind and solar power output during certain periods; , for The electrical and thermal power output of CHP during the time period; for ORC waste heat power generation output power during the period; Output electrical power to the biomass waste energy conversion unit; , for Time-of-use energy storage discharge and charging power; , They are respectively Power consumption of EB and ER during the same period; for Power consumption for wastewater treatment during specific time periods; , for Power consumption of time-phase electrolyzers and PSA equipment; for Power consumption of carbon capture equipment during specific time periods; (26) In the formula: for System electrical load during specific time periods; , for Heat output from waste heat boilers and electric boilers during certain periods; , for Heat generated by the electrolytic cell and ammonia production equipment during the time period; , for Heat generation from time-limited gas-fired boilers and biomass waste energy conversion units; , for Time period for thermal storage tank release and thermal storage capacity; for Heat consumption of AC during the period; (27) In the formula: for System gas load during specific time periods; for Gas purchase volume during specific time periods; for Gas production of the biomass waste energy conversion unit during a given period; , for CHP and gas consumption of gas-fired boilers during different time periods; (28) In the formula: for System cooling load during certain periods; , They are respectively Output power of time-limited electric chillers and absorption chillers; , for Time period for cold storage tank release, cold storage capacity; Biomass waste energy conversion unit constraints (29) In the formula: , These are the upper and lower limits for waste treatment by the biomass waste energy conversion unit, respectively. , These are the upper and lower limits for wastewater treatment by biomass waste energy conversion units; , The maximum and minimum climbing power for biogas production rate; , The maximum and minimum ramp power for the biomass waste energy conversion unit to process waste.

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