Multi-energy waste treatment system considering carbon emissions

Abstract

The present application relates to a multi-energy waste treatment system considering carbon emissions, comprising a waste treatment unit for generating electric energy, thermal energy and fuel gas by treating waste; a multi-energy coupling unit connected with a load end, a waste treatment unit, an external energy end and an energy storage end respectively, and configured to adjust the amount of electric energy, thermal energy and fuel gas input from the waste treatment unit and the external energy end to the load end according to the gas load, electric load and thermal load of the load end; a P2G unit connected with the load end and configured to produce fuel gas by consuming CO2 through methanation reaction; and a carbon trading cost model loaded in the multi-energy coupling unit and configured to: subtract the carbon emissions converted from the consumed CO2 when the P2G unit produces fuel gas from the carbon emissions generated when the waste treatment unit and the external energy end generate electric energy, thermal energy and fuel gas, to obtain the actual carbon emissions of the system, and when the actual carbon emissions are less than the carbon allocation quota, the carbon trading cost is negative.

Description

Technical Field

[0001] This invention relates to the field of energy technology, specifically to a multi-energy waste treatment system that takes carbon emissions into account. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] At present, energy supply and demand are showing a diversified trend, but the energy consumption structure is unreasonable. The consumption of renewable energy is not high and the types are relatively simple, usually mainly biogas and solar energy, while wind energy, water conservancy, geothermal energy and other energy sources have not been effectively utilized.

[0004] In response to the above problems, some regions are developing clean energy according to local conditions. For example, in areas suitable for biogas projects, small and medium-sized biogas digesters are being built to optimize the energy consumption structure; or efforts are being made to increase the proportion of electricity in energy consumption and accelerate the application of electricity substitution technologies.

[0005] Waste pyrolysis gasification is a method of waste treatment that saves 50% to 80% of land compared to waste incineration and biological landfill technologies. If the gas produced per ton of waste is used for power generation, the power generation efficiency can be increased by about 50% compared to other waste-to-energy technologies.

[0006] Waste can be processed to generate various forms of energy such as electricity, heat and gas, which can optimize the existing energy consumption structure. However, the waste processing process releases carbon dioxide, causing environmental problems and limiting carbon emissions, which is not conducive to the demand for carbon emission reduction. Summary of the Invention

[0007] To address at least one of the technical problems existing in the background art, the present invention provides a multi-energy waste treatment system that considers carbon emissions. It utilizes multiple energy types, including waste treatment systems, conventional water, electricity, and gas grids, P2G (renewable energy generation technology) equipment, photovoltaic equipment, gas turbines, and gas boilers, to form an energy supply terminal that meets user needs. Based on the multi-energy system, a carbon trading mechanism is introduced, and a model and corresponding strategy for the system to operate with low carbon emissions are proposed with the goal of minimizing costs.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A first aspect of the present invention provides a multi-energy waste treatment system that takes carbon emissions into account, comprising:

[0010] Waste treatment unit, which processes waste to generate electricity, heat and gas;

[0011] The multi-energy coupling unit is connected to the load end, waste treatment unit, external energy end and energy storage end respectively. According to the gas load, electric load and heat load of the load end, it adjusts the amount of electrical energy, heat energy and gas input to the load end by the waste treatment unit and the external energy end.

[0012] The P2G unit is connected to the load end and consumes CO2 to produce methane through a methanation reaction to provide fuel gas.

[0013] The multi-energy coupling unit loads the carbon trading cost model and is configured as follows:

[0014] The carbon emissions generated when the waste treatment unit and external energy source produce electricity, heat, and gas are subtracted from the carbon emissions from the CO2 conversion when the P2G unit produces gas, to obtain the actual carbon emissions of the system. When the actual carbon emissions are less than the carbon allocation quota, the carbon trading cost is negative.

[0015] The carbon trading cost model is as follows:

[0016]

[0017] ε represents the carbon trading cost of the system; α represents the trading price per unit of carbon emission rights in the carbon trading market; α represents the carbon trading price increase rate; β represents the compensation coefficient; l represents the range length of the system's carbon emissions; E s Allocate quotas for the system's free carbon emission rights; E a This represents the system's actual carbon emissions.

[0018] The waste treatment unit includes at least one of the following: a waste pyrolysis gasification furnace unit, a gas-fired boiler unit, a gas turbine unit, and a gas turbine combined heat and power unit.

[0019] The waste treatment unit obtains the electrical energy generated in the t-th time period based on the heat of flue gas generated from pyrolytic waste and the heat of flue gas generated from combustible waste.

[0020] In the waste treatment unit, the high-temperature flue gas obtained from the combustion of combustible waste in the incinerator is used to heat the waste heat boiler. The mixed combustible gas produced by the pyrolysis of pyrolysis waste in the pyrolysis gasification furnace is injected into the combustion chamber for complete combustion. The resulting high-temperature flue gas, along with the incinerator, heats the waste heat boiler. The generated high-pressure steam drives a steam turbine to generate electricity. The generated electricity is as follows:

[0021]

[0022] In the formula, P g,h,t The heat generated by the flue gas from pyrolyzable waste; P bg,h,t P is the heat generated from flue gas produced by combustible waste; e,tη represents the electrical energy generated by the steam turbine in the t-th time period; g η mgb,h These are the operating efficiency of the pyrolysis gasifier and the operating efficiency of the mixed gas combustion chamber, respectively; η bg For incinerator operating efficiency; v g v bg The low-grade calorific values ​​of pyrolytic waste and combustible waste are respectively; η ge For the power generation efficiency of the steam turbine; η pe This refers to the plant power consumption rate of the waste treatment unit.

[0023] The free carbon emission rights allocation includes the carbon emission rights allocation used by external energy sources when supplying electricity, heat, and gas to loads, and the carbon emission rights allocation used by waste treatment units when generating electricity, heat, and gas.

[0024] The carbon emission rights allocation for the electricity, heat and gas generated by the waste treatment unit includes the sum of the products of the power supply of the waste treatment unit, the power supply and heating power of the gas turbine and the heating power of the gas boiler in the t-th time period, and the carbon emission rights allocation per unit of power supply, respectively.

[0025] The carbon emissions generated by the system during actual operation are shown in the following formula:

[0026]

[0027]

[0028]

[0029] P gtb,t =P gt,e,t +P gt,h,t +P gb,h,t ;

[0030] E e,1 E wd,1 E gtb,1 P gtb,t These represent carbon emissions from purchased electricity, carbon emissions from waste treatment units, carbon emissions from gas turbines and gas boilers, and the output power of gas turbines and gas boilers per unit time, respectively; a1, b1, and c1 are the carbon emission coefficients for coal combustion, respectively; a2, b2, and c2 are the carbon emission calculation coefficients for waste treatment units, respectively; and a3, b3, and c3 are the carbon emission calculation coefficients for natural gas power supply, respectively.

[0031] When a P2G unit produces a certain volume of natural gas, the amount of carbon dioxide consumed is:

[0032]

[0033] In the formula, These represent the molar volume of methane and the molar mass of carbon dioxide, respectively.

[0034] The volume V of natural gas produced by the P2G unit CH4 and power consumption P p2g The relationship between them is:

[0035]

[0036] In the formula, LHV is the lower heating value of natural gas; η p2g For efficiency.

[0037] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0038] The energy supply terminal that meets user needs is formed by utilizing multiple energy types, including waste treatment systems, conventional water, electricity, gas grids, and P2G (renewable energy generation technology) equipment. Based on the multi-energy system, a carbon trading mechanism is introduced, and a model and corresponding strategies for the system to operate in a low-carbon manner are proposed with the goal of minimizing costs. Attached Figure Description

[0039] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0040] Figure 1 This is a schematic diagram of a domestic and industrial waste treatment process provided by one or more embodiments of the present invention;

[0041] Figure 2 This is a schematic diagram of a multi-energy system for waste treatment in industrial parks and urban production and life that takes carbon emissions into account, provided by one or more embodiments of the present invention. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0045] As described in the background section, the current energy consumption structure is unreasonable, with a low proportion of renewable energy and a relatively limited variety, primarily relying on biogas and solar energy, while wind, hydropower, and geothermal energy are not effectively utilized. According to relevant data, the proportion of electricity consumption in primary energy consumption, calculated using the equivalent method, is 11.9%, and calculated using the equivalent method, it is only 4.8%, lower than fuel oil consumption and only slightly higher than solar energy and biogas. This results in excessively low electricity consumption and a generally low level of electrification.

[0046] Waste can be processed to generate various forms of energy such as electricity, heat and gas, which can optimize the existing energy consumption structure. However, the waste processing process releases carbon dioxide, causing environmental problems and limiting carbon emissions, which is not conducive to the demand for carbon emission reduction.

[0047] Therefore, the following embodiments present a multi-energy waste treatment system that takes carbon emissions into account. It utilizes a variety of energy types, including waste treatment systems, conventional water, electricity, gas grids, P2G (renewable energy generation technology) equipment, photovoltaic equipment, gas turbines, and gas boilers, to meet the energy supply terminal needs of users. Based on the multi-energy system, a carbon trading mechanism is introduced, and a model and corresponding strategies for the system to operate in a low-carbon manner are proposed with the goal of minimizing costs.

[0048] Example 1:

[0049] like Figure 1-2 As shown, the purpose of this embodiment is to provide a multi-energy waste treatment system that takes carbon emissions into account, including:

[0050] Waste treatment units, including but not limited to waste pyrolysis gasification furnace units, gas boiler units, micro gas turbine cogeneration units and fuel cells, process waste to generate electricity, heat and gas;

[0051] The multi-energy coupling unit is connected to the load end, waste treatment unit, external energy end and energy storage end respectively. According to the gas load, electric load and heat load of the load end, it adjusts the amount of electrical energy, heat energy and gas input to the load end by the waste treatment unit and the external energy end.

[0052] The P2G unit is connected to the load end and consumes CO2 to produce methane through a methanation reaction to provide fuel gas.

[0053] The multi-energy coupling unit loads the carbon trading cost model and is configured as follows:

[0054] The carbon emissions generated when the waste treatment unit and external energy source produce electricity, heat, and gas are subtracted from the carbon emissions from the CO2 conversion when the P2G unit produces gas, to obtain the actual carbon emissions of the system. When the actual carbon emissions are less than the carbon allocation quota, the carbon trading cost is negative.

[0055] The carbon trading cost model is as follows:

[0056]

[0057] ε represents the carbon trading cost of the system; α represents the trading price per unit of carbon emission rights in the carbon trading market; α represents the carbon trading price increase rate; β represents the compensation coefficient; l represents the range length of the system's carbon emissions; E s Allocate quotas for the system's free carbon emission rights; E a This represents the system's actual carbon emissions.

[0058] Specifically:

[0059] Waste treatment units utilize physical, chemical, biological, physicochemical, and biochemical methods to transform waste into a state suitable for transportation, storage, utilization, or disposal. The goals of solid waste treatment are detoxification, volume reduction, and resource recovery. Currently, the main methods employed include compaction, crushing, sorting, solidification, incineration, and biological treatment. This aims to achieve effective and rational resource utilization and reduce carbon emissions.

[0060] The multi-energy coupling unit can store energy to balance the system. The gas load is mainly provided by the waste pyrolysis gasification furnace; the electric load is jointly provided by the micro gas turbine cogeneration unit and the fuel cell. When the electric load is low, the gas produced by the waste pyrolysis gasification furnace can be stored. When the electric load is high, the processing capacity of the waste pyrolysis gasification furnace can be increased to increase the gas production, and then the electricity supply can be increased through the micro gas turbine cogeneration unit; the heat load is jointly provided by the micro gas turbine cogeneration unit and the electric boiler.

[0061] Waste, after treatment, can be used for heating, gas supply, or power generation. Different treatment methods have different energy utilization rates and are also subject to various limitations. The comparison results are shown in Table 1:

[0062] Table 1: Comparison of different waste treatment methods

[0063]

[0064]

[0065] Waste collection and disposal involves steps such as collection, transportation, and landfilling. The entire process is cumbersome, requires a large area, wastes resources, and fails to effectively utilize waste. Waste pyrolysis technology, by pyrolyzing municipal solid waste, yields a mixed combustible gas containing methane and hydrogen, and effectively decomposes toxic substances. Furthermore, with the development of waste-to-energy incineration technology, its energy efficiency is continuously improving. This embodiment integrates waste pyrolysis and waste-to-energy incineration, establishing an energy supply model for waste treatment units in industrial parks or cities. Figure 1 For the process of cleaning up domestic and industrial waste, Figure 2 This refers to the energy flow conversion process for waste treatment within a park or city.

[0066] In waste pyrolysis technology, the high-temperature flue gas obtained from the combustion of combustible waste in an incinerator is used to heat a waste heat boiler. The mixed combustible gas produced by the pyrolysis of the waste in a pyrolysis gasification furnace is injected into the combustion chamber for complete combustion. The resulting high-temperature flue gas, along with the incinerator, heats the waste heat boiler. The generated high-pressure steam then drives a turbine to generate electricity, as shown in Formula 1.

[0067]

[0068] In the formula, P g,h,t The heat generated by the high-temperature flue gas from the pyrolysis of waste; P bg,h,t The heat from the high-temperature flue gas generated by combustible waste; P e,t Let η be the electrical energy generated by the steam turbine in the t-th time period. g η mgb,h For the operating efficiency of the pyrolysis gasifier and the operating efficiency of the mixed gas combustion chamber; η bg For incinerator operating efficiency; v g v bg The low-grade calorific values ​​of pyrolytic waste and combustible waste are respectively 14380 kJ / kg and 5000 kJ / kg in this embodiment; η ge For the power generation efficiency of the steam turbine; η pe This refers to the plant power consumption rate of the waste treatment unit.

[0069] Carbon emissions are generated during the process of generating electricity from waste pyrolysis. Due to carbon emission limits, if the actual carbon emissions generated by a production enterprise exceed its allocated quota, it needs to purchase carbon emission credits from the carbon trading market, which increases the enterprise's carbon trading costs. Conversely, when carbon emissions are lower than the allocated quota, the excess carbon emission credits can be sold on the carbon trading market to generate revenue. The carbon trading mechanism can fully tap the low-carbon emission reduction potential of major production enterprises.

[0070] Regarding the model for allocating free carbon emission credits, the carbon emission credits include electricity, waste treatment units, gas turbines, and gas-fired boilers, as shown in the following formula:

[0071] E s =E e +E wd +E gt +E gb (2)

[0072]

[0073]

[0074]

[0075]

[0076] In the formula, E s Allocate quotas for free carbon emission rights for the entire system; E e E wd E gt E gb These represent the carbon emission allowances allocated for purchased electricity, waste treatment units, gas turbines, and gas-fired boilers, respectively; T represents a 24-hour day, and Δt represents a 1-hour time period within that day; δ e The carbon emission allowance per unit of electricity supplied is set at 0.798 t / MW·h, δ h Carbon emission rights allocation per unit of heating power; P e,t P wd,e,t P gt,e,t P gt,h,t P gb,h,t These represent the system's power purchase from the grid in time period t, the power supplied by the waste treatment unit in time period t, the power supplied by the gas turbine and the heating power in time period t, and the heating power of the gas boiler in time period t, respectively.

[0077] The carbon emissions generated by the system during actual operation can be expressed by the following formula:

[0078]

[0079]

[0080]

[0081] P gtb,t =P gt,e,t +P gt,h,t +P gb,h,t (4)

[0082] E e,1 E wd,1 E gtb,1 P gtb,tThese represent carbon emissions from purchased electricity, carbon emissions from waste treatment units, carbon emissions from gas turbines and gas-fired boilers, and the output power of gas turbines and gas-fired boilers per unit time. a1, b1, and c1 are the carbon emission coefficients for coal combustion, a2, b2, and c2 are the carbon emission calculation coefficients for waste treatment units, and a3, b3, and c3 are the carbon emission calculation coefficients for natural gas power supply.

[0083] The power-to-gas (P2G) equipment is coupled with other devices. The integration of P2G not only strengthens electrical coupling but also effectively absorbs renewable energy. Its operation involves two main steps: power-to-hydrogen and power-to-natural gas. Power-to-hydrogen involves electrolyzing water to produce oxygen and hydrogen, while power-to-natural gas involves a catalytic reaction to produce methane after the hydrogen conversion. The volume V of natural gas produced by P2G (Power-to-Gas technology, which uses surplus electricity from wind and solar power to electrolyze water to produce hydrogen, which is then supplied to existing gas pipeline networks; or uses electricity, water, and atmospheric CO2 to produce methane through methanation to provide fuel) is... CH4 and power consumption P p2g The relationship between them can be expressed as:

[0084]

[0085] In the formula, LHV is the lower heating value of natural gas; η p2g For P2G efficiency, the carbon dioxide consumed in producing a certain volume of natural gas can be expressed as:

[0086]

[0087] In the formula, Represented by the molar volume of methane and the molar mass of carbon dioxide. The amount of carbon dioxide consumed to generate a certain volume of methane can be used to demonstrate that P2G improves carbon dioxide emission reduction.

[0088] The system construction process is as follows:

[0089] Step 1: Establish a carbon emission allowance allocation model, including electricity, waste treatment units, gas turbines, and gas boilers. During the production process, if a production enterprise's actual carbon emissions exceed its allocated allowance, it needs to purchase carbon emission allowances from the carbon trading market, thus increasing the enterprise's carbon trading costs. Conversely, when carbon emissions are lower than the allocated allowance, the excess carbon emission allowances can be sold on the carbon trading market to generate revenue.

[0090] Step 2: Calculate the carbon dioxide absorbed by the power-to-gas conversion equipment during operation.

[0091] Step 3: Establish a carbon trading cost model. A compensation coefficient is introduced into the carbon trading model. When a company's actual carbon emissions are lower than its free carbon emission allocation (i.e., the carbon trading cost is negative and the company gains a profit), the compensation coefficient will be used as an important parameter in the calculation of carbon trading costs, increasing the incentive for companies that actively reduce emissions, as follows:

[0092]

[0093] ε represents the carbon trading cost of the system; α represents the trading price per unit of carbon emission rights in the carbon trading market; β represents the growth rate of the carbon trading price; and l represents the range length of the system's carbon emissions.

[0094] Step 4: Establish an economic strategy for waste treatment that includes carbon emissions, taking into account the system's energy purchase costs, operation and maintenance costs, and carbon trading costs. Adopt a low-carbon economic operation strategy, and rationally formulate carbon trading prices and compensation coefficients to effectively reduce the system's carbon emissions while ensuring economic efficiency.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-energy waste treatment system considering carbon emissions, characterized in that: include: Waste treatment unit, which processes waste to generate electricity, heat and gas; The multi-energy coupling unit is connected to the load end, waste treatment unit, external energy end and energy storage end respectively. According to the gas load, electric load and heat load of the load end, it adjusts the amount of electrical energy, heat energy and gas input to the load end by the waste treatment unit and the external energy end. The P2G unit is connected to the load end and consumes CO2 to produce methane through a methanation reaction to provide fuel gas. The multi-energy coupling unit loads the carbon trading cost model and is configured as follows: The actual carbon emissions of the system are obtained by subtracting the carbon emissions from the conversion of CO2 consumed when the P2G unit generates gas from the carbon emissions generated by the waste treatment unit and external energy sources when generating electricity, heat and gas. The carbon trading cost of the system is then calculated based on the carbon trading cost model. The carbon emissions generated when waste treatment units and external energy sources produce electricity, heat, and gas are shown in the following formula: ； , , , These are carbon emissions from purchased electricity, carbon emissions from waste treatment units, carbon emissions from gas turbines and gas boilers, and the output power of gas turbines and gas boilers per unit time. , , These are the carbon emission coefficients for coal combustion; , , These are the carbon emission calculation coefficients for waste treatment units; , , These are the carbon emission calculation coefficients for natural gas power supply. The amount of electricity purchased by the system from the grid in time period t. For gas turbine Power supply during each time period; For gas turbine Heating power during each time period; For gas boilers Heating capacity for a given time period Power supply of the waste treatment unit in the t-th time period; The carbon trading cost model is as follows: The carbon trading cost of the system; The trading price per unit of carbon emission rights in the carbon trading market; The percentage increase in carbon trading prices; The compensation coefficient; The range length of the system's carbon emissions; Allocate quotas of free carbon emission rights for the system; This represents the system's actual carbon emissions. Regarding the model for allocating free carbon emission credits, the carbon emission credits include electricity, waste treatment units, gas turbines, and gas-fired boilers, as shown in the following formula: In the formula, Allocate quotas of free carbon emission rights for the entire system; , , , These are the carbon emission allowances allocated for purchased electricity, waste treatment units, gas turbines, and gas boilers, respectively; T represents 24 hours in a day. For the 1-hour time period; The carbon emission allowance per unit of electricity supplied is set at 0.798 t / MW·h. Carbon emission rights allocated per unit of heating power; , , , , These represent the system's power purchase from the grid in time period t, the power supplied by the waste treatment unit in time period t, the power supplied by the gas turbine and the heating power in time period t, and the heating power of the gas boiler in time period t, respectively.

2. The multi-energy waste treatment system considering carbon emissions as described in claim 1, characterized in that: The waste treatment unit includes at least one of the following: a waste pyrolysis gasification furnace unit, a gas boiler unit, a gas turbine unit, and a gas turbine combined heat and power unit.

3. The multi-energy waste treatment system considering carbon emissions as described in claim 1, characterized in that: When a P2G unit produces a certain volume of natural gas, the amount of carbon dioxide consumed is: ； In the formula, , V CH4 These represent the molar volume of methane, the molar mass of carbon dioxide, and the volume of natural gas produced by the P2G unit, respectively.

4. The multi-energy waste treatment system considering carbon emissions as described in claim 3, characterized in that: The volume V of natural gas produced by the P2G unit CH4 and power consumption P p2g The relationship between them is: ； In the formula, It is the lower heating value of natural gas; For efficiency.

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