Carbon footprint accounting method for preparing regenerated ceramsite product based on multi-source solid waste

Abstract

The invention provides a carbon footprint accounting method for preparing a regenerated ceramsite product based on multi-source solid waste, which comprises the following steps: quantitatively accounting greenhouse gas emission in three stages of raw material acquisition, product production and in-site transportation, and establishing a regenerated ceramsite full-flow carbon footprint model; and scientific, systematic and standardized evaluation of carbon emission in the whole production process is realized, and reliable technical support is provided for low-carbon evaluation, green authentication and life cycle management of the regenerated building materials. The method comprises the following steps: (1) determining a function unit and a system boundary; (2) collecting the use amount of raw and auxiliary materials, energy consumption, in-plant transportation volume and distance primary data according to a production process; (3) determining greenhouse gas emission factors of raw materials, energy and transportation; and (4) calculating the greenhouse gas emission in the raw material acquisition stage, the production and processing stage and the in-field transportation stage according to stages.

Description

Technical Field

[0001] This invention relates to a method for calculating the carbon footprint of recycled ceramsite products prepared from multi-source solid waste. Background Technology

[0002] As a major source of energy consumption and greenhouse gas emissions, the building materials industry is facing the dual pressures of emission reduction and green transformation. Traditional clay ceramsite production uses natural clay or shale as the main raw material and requires high-temperature firing, resulting in high consumption of primary resources, high energy intensity, and high carbon dioxide emissions, which is detrimental to the industry's low-carbon development.

[0003] In recent years, the resource utilization of multi-source solid waste has become an important research direction in the field of building materials. Construction waste, sludge, demolition waste, decoration waste, garden waste, and general industrial solid waste all possess potential for substitution and utilization. Through synergistic proportioning and high-temperature calcination, stable recycled ceramsite materials can be prepared, achieving the goal of "material from waste" recycling. However, existing research mainly focuses on the preparation process and performance optimization of solid waste ceramsite, with relatively insufficient research on the carbon emission characteristics and carbon footprint accounting methods of its entire production process.

[0004] Existing carbon emission assessment methods mostly focus on traditional virgin ceramsite or single-raw-material systems, making them difficult to apply to the production process of recycled ceramsite, which is co-produced from multiple solid waste raw materials. The main problems are: inconsistent system boundary delineation, lack of consistent standards for dividing raw material acquisition, transportation, and processing stages, leading to biases in accounting methods; lack of unified standards for activity data collection and emission factor matching, with significant differences in data sources and emission parameters used in different studies, especially in the areas of solid waste fuels, biomass, and general industrial solid waste, where reliable emission coefficients are lacking; furthermore, existing life cycle accounting methods mostly focus on single stages or energy consumption stages, failing to achieve full-process greenhouse gas emission accounting from raw material acquisition to finished product delivery, and thus failing to comprehensively reflect the carbon emission characteristics and emission reduction potential of recycled ceramsite products.

[0005] Therefore, there is an urgent need to establish a product carbon footprint accounting method based on the preparation of recycled ceramsite from multi-source solid waste, so as to standardize the accounting boundaries, clarify the emission types, unify the data caliber, realize the scientific assessment of greenhouse gas emissions in the entire process of recycled ceramsite production, and provide technical support for carbon emission control and green product evaluation of recycled building materials. Summary of the Invention

[0006] The purpose of this invention is to provide a carbon footprint accounting method for the preparation of recycled ceramsite products based on multi-source solid waste. By quantitatively calculating greenhouse gas emissions in the three stages of raw material acquisition, product production, and on-site transportation, a carbon footprint model of the entire process of recycled ceramsite is established. This enables a scientific, systematic, and standardized assessment of carbon emissions throughout the entire production process, providing reliable technical support for the low-carbon evaluation, green certification, and life cycle management of recycled building materials.

[0007] The technical solution adopted by the present invention to solve the above problems is:

[0008] A method for calculating the carbon footprint of recycled ceramsite prepared from multi-source solid waste, characterized by the following steps:

[0009] (a) Determine the functional units and system boundaries;

[0010] (ii) Collect preliminary data on raw and auxiliary material usage, energy consumption, and in-plant transportation volume and distance according to the production process;

[0011] (iii) Determine the greenhouse gas emission factors of raw materials, energy and transportation;

[0012] (iv) Calculate greenhouse gas emissions for the raw material acquisition stage, production and processing stage, and on-site transportation stage by stage; summarize the life cycle greenhouse gas emissions according to formula (1), and convert them into unit product carbon footprint value according to formula (2). The calculation formula is as follows:

[0013]

[0014] Where E CHG Total CO2 emissions over the life cycle of expanded clay aggregate; GWP i C represents the GWP value of the i-th type of greenhouse gas; raw CO2 emissions during the raw material acquisition stage; C prod CO2 emissions during the production and processing stage; C trans CO2 emissions during the transportation phase;

[0015] CFP CHG =E CHG / G product ……(2),

[0016] CFP CHG Carbon footprint of expanded clay products; E CHG This represents the total CO2 emissions over the lifecycle of expanded clay aggregate; G product Total output product quantity.

[0017] In this invention, in step (a), the system boundary is defined as: from cradle to gate, covering the raw material acquisition stage, the product manufacturing stage, and the on-site transportation stage;

[0018] The raw material acquisition stage includes two sub-processes: raw material production and transportation.

[0019] The product manufacturing stage described above covers the entire production process from raw material intake to finished ceramsite product delivery, including:

[0020] (1) Construction waste pretreatment: sorting, crushing and screening the construction waste and slag entering the plant;

[0021] (2) Separation of metals / slag and extraction of light and heavy materials: Separate recyclable metals from inert slag and extract recycled aggregates, combustible light materials and recycled resources;

[0022] (3) Combustible gasification for energy supply: general industrial solid waste and biomass are gasified to generate combustible gas for energy supply to the production system.

[0023] (4) Ceramsite production: including raw material proportioning, granulation, calcination, cooling and conveying processes, to form recycled ceramsite products that meet performance requirements;

[0024] The aforementioned on-site transportation stage refers to the short-distance transport of materials and products between different processes within the factory area and their warehousing.

[0025] In step (iii) of this invention, the types of greenhouse gas emissions include: CO2 emitted during the production of raw and auxiliary materials; CO2 generated during the transportation of raw and auxiliary materials and finished products within the factory; CO2 indirectly emitted due to electricity used in each production process; CO2 generated from the combustion of fossil fuels; CH4 and N2O generated during the gasification and combustion of biomass fuels; and CO2, CH4, and N2O generated from the gasification and combustion of fossil fuels in general industrial solid waste.

[0026] In step (iv) of this invention, the greenhouse gas emissions in the raw material acquisition stage consist of emissions from the production of raw and auxiliary materials and emissions from the transportation of raw and auxiliary materials, and the calculation relationship is as shown in equation (3):

[0027] C raw =C material +C raw-trans ……(3),

[0028] Where C raw C represents the carbon dioxide equivalent emissions during the raw material acquisition stage. material Emissions from the production of raw and auxiliary materials; C raw-trans This refers to the emissions from the transportation of raw and auxiliary materials from the point of origin to the ceramsite plant;

[0029] The emissions from the production of raw and auxiliary materials are calculated using the following formula:

[0030]

[0031] Where EFi AD is the greenhouse gas emission factor of the i-th raw and auxiliary material; i For the activity data of the i-th type of raw and auxiliary material;

[0032] The emissions from the transportation of raw and auxiliary materials are calculated using the following formula:

[0033]

[0034] Where M supply，i D represents the transportation volume of the i-th type of raw material; distance，i For the corresponding transportation distance; T emission，i This represents the unit freight emission factor for the mode of transportation used.

[0035] The emissions during the production stage of the product described in this invention include four parts: electricity consumption, biomass gasification combustion, general industrial solid waste gasification combustion, and fossil fuel combustion. Their calculation relationship is shown in equation (6):

[0036] C prod =C elec +C bio +C isw +C fossil ……(6),

[0037] Where C prod CO2 emissions during the production and processing stage; C elec CO2 emissions from electricity consumption during the production and processing stage; C bio Carbon dioxide emissions related to biomass gasification combustion; C isw This refers to the CO2 emissions from the gasification and combustion of general industrial solid waste during the production and processing stage; C fossil This refers to the CO2 emissions caused by the combustion of fossil fuels during the production and processing stages.

[0038] The formula for calculating CO2 emissions from electricity consumption described in this invention is shown in (7):

[0039]

[0040] C elec CO2 emissions from electricity consumption during the production and processing stage; M elec，i M represents the electricity consumption during the product manufacturing stage. green，i Green electricity offset during the product manufacturing phase; CEF elec，i Local greenhouse gas emission factor for electricity; MF mat The percentage of the target product's quality during the production process;

[0041] The formula for calculating the mass percentage of the target product during the production process is shown in (8):

[0042]

[0043] Where M target The target product quality produced during the manufacturing process; M total The quality of all products produced during the manufacturing and processing process.

[0044] The calculation relationship of this invention is shown in equation (9):

[0045]

[0046] C bio Carbon dioxide emissions related to biomass gasification and combustion; This refers to the amount of methane emissions converted into carbon dioxide emissions during the biomass gasification and combustion process. This refers to the amount of nitrous oxide emissions converted into carbon dioxide emissions during biomass gasification and combustion.

[0047] The formula for calculating the amount of methane emissions converted to carbon dioxide during the biomass gasification and combustion process is shown in (10):

[0048]

[0049] Fuel is the amount of methane emissions converted to carbon dioxide during biomass gasification and combustion. bio，i NCV represents the consumption of biomass fuel of type i; bio，i For the lower heating value of the i-th type of biomass fuel, ; The methane emission factor for biomass combustion of type i; The 100-year global warming potential of methane;

[0050] The formula for calculating the amount of nitrous oxide emissions converted to carbon dioxide during the biomass gasification combustion process is shown in (11):

[0051]

[0052] This refers to the emission of nitrous oxide during biomass gasification combustion, converted to carbon dioxide equivalents. bio，i NCV represents the consumption of biomass fuel of type i; bio，i The lower heating value of the i-th type of biomass fuel; The emission factor for nitrous oxide from biomass combustion of type i; This represents the global warming potential of nitrous oxide.

[0053] The CO2 emissions from the gasification and combustion of general industrial solid waste during the production and processing stage described in this invention include direct CO2 emissions, methane emissions, and nitrous oxide emissions, as shown in formula (12):

[0054]

[0055] Where C isw This refers to the total CO2 emissions caused by the gasification and combustion of general industrial solid waste during the production and processing stage. This refers to the direct CO2 emissions generated from the gasification and combustion of general industrial solid waste within the project boundary. This refers to the amount of methane emissions converted into carbon dioxide emissions during the combustion process of general industrial solid waste gasification. This refers to the amount of nitrous oxide emissions converted into carbon dioxide emissions during the combustion process of general industrial solid waste gasification.

[0056] The formula for calculating the direct CO2 emissions generated by the gasification and combustion of general industrial solid waste during the production and processing stage is shown in (13):

[0057]

[0058] in Q represents the total CO2 emissions from the combustion of general industrial solid waste within the project boundary; isw，i For the quality of general industrial solid waste i supplied; OF i Combustion efficiency for general solid waste type i; FCC i Total carbon content in general industrial solid waste; FFC i The fossil carbon content in general industrial solid waste;

[0059] The formula for calculating the amount of methane emissions converted to carbon dioxide emissions during the combustion process of general industrial solid waste gasification is shown in (14):

[0060]

[0061] in Q represents the amount of methane emissions converted to carbon dioxide during the combustion process of general industrial solid waste gasification; isw，i The quantity of general industrial solid waste i supplied; The methane emission factor is the methane emission factor in the combustion process after gasification of general industrial solid waste. The global warming potential of methane;

[0062] The formula for calculating the carbon dioxide emissions from the combustion of general industrial solid waste after gasification is shown in (15):

[0063]

[0064] in This refers to the emission of nitrous oxide during the combustion process of general industrial solid waste gasification, converted into carbon dioxide equivalents; Q isw，iThe quantity of general industrial solid waste i supplied; Nitrous oxide emission factor during the combustion process of general industrial solid waste gasification; This represents the global warming potential of nitrous oxide.

[0065] The CO2 emissions generated by the combustion of fossil fuels during the production stage of the product described in this invention are calculated using the formula shown in (16):

[0066]

[0067] Where C fossil CO2 emissions from the combustion of fossil fuel type i; AD i Specify the consumption amount of fossil fuel i used for fuel combustion; CC i The carbon content of fossil fuel type i; OF i The carbon oxidation rate of fossil fuel type i;

[0068] The formula for calculating the carbon content of the fossil fuel is shown in (17):

[0069] CC i =NCV i ×EF i ……(17),

[0070] NCV i The lower heating value of fossil fuel type i; EF i Carbon content per unit calorific value of fossil fuel type i;

[0071] The calculation relationship for CO2 generated during the transportation of the finished product within the factory area is shown in equation (18):

[0072]

[0073] Where C trans Carbon emissions from transporting finished products to warehouses; M supply，i D represents the transport volume of the i-th type of finished product; distance，i T represents the transportation distance of the i-th type of finished product; emission，i Carbon emission factors in transportation form.

[0074] Compared with existing technologies, this invention has the following characteristics and beneficial effects: Based on fully considering the differences in raw materials from multiple solid waste sources and the coupling characteristics of processes, a "cradle-to-gate" carbon footprint accounting system covering the three stages of raw material acquisition, product production, and on-site transportation is constructed. Specifically: (1) For the first time, a unified accounting boundary and methodological framework is proposed for multi-source solid waste composite systems, making up for the insufficient applicability of traditional primary ceramsite models; (2) The emission factors and standards of national, industry, and international databases are integrated, significantly improving the consistency, comparability, and universality of accounting results; (3) The principle of "zero inclusion" of recycled raw materials and separate accounting for transportation is clearly defined, ensuring that emission allocation conforms to LCA logic and objectively reflects the carbon reduction contribution of recycled raw materials; (4) A modular calculation model is established, which can be flexibly configured according to raw material type (engineering slag, sludge, demolition / renovation waste, garden waste, biomass, etc.) and process path, making it easy to promote and apply in different projects and enterprises; (5) The accounting results can directly support the evaluation and certification of low-carbon building materials, green building evaluation, and the construction of regional / industry LCA databases, which has significant engineering application value and promotion significance. Attached Figure Description

[0075] Figure 1 This is a schematic diagram of the carbon footprint accounting method architecture according to an embodiment of the present invention;

[0076] Figure 2 This is a schematic diagram of the process flow for preparing recycled ceramsite products based on multi-source solid waste, as described in an embodiment of the present invention. Detailed Implementation

[0077] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0078] I. A method for calculating the carbon footprint of recycled ceramsite products prepared from multi-source solid waste according to an embodiment of the present invention includes the following steps:

[0079] (a) Determine the functional unit and system boundary: Set the functional unit to 1m 3 The system boundary for recycled ceramsite is: from cradle to gate, covering the raw material acquisition stage, product manufacturing stage, and on-site transportation stage.

[0080] In the implementation of this invention, such as Figure 1 As shown, the system boundary adopts a "cradle-to-gate" model, which covers the stage from raw material acquisition to final product (C). raw Product manufacturing stage (C) prod ) to the on-site transportation stage (C trans The entire process of ).

[0081] The raw material acquisition stage includes the production and transportation of raw materials, and is used to account for greenhouse gas emissions from multi-source solid waste (such as construction waste, sludge and contaminated soil, demolition waste, decoration waste, garden waste, general industrial solid waste and biomass, etc.).

[0082] The product manufacturing stage covers all processes from raw material intake to finished ceramsite product delivery, including:

[0083] (1) Construction waste pretreatment: sorting, crushing and screening the construction waste and slag entering the plant;

[0084] (2) Separation of metals / slag and extraction of light and heavy materials: Separate recyclable metals from inert slag and extract recycled aggregates, combustible light materials and recycled resources;

[0085] (3) Combustible gasification for energy supply: general industrial solid waste and biomass are gasified to generate combustible gas for energy supply to the production system.

[0086] (4) Ceramsite production: including raw material proportioning, granulation, calcination, cooling and conveying processes, to form recycled ceramsite products that meet performance requirements.

[0087] The on-site transportation stage refers to the short-haul transportation of materials and finished products between different production units within the factory area and the process of warehousing finished products.

[0088] This embodiment selects "cradle to gate" as the system boundary, primarily based on the following considerations: Recycled ceramsite products are mainly used as filler or lightweight aggregate in construction projects after leaving the factory. The carbon emissions during their downstream use are significantly affected by external factors such as construction methods, project characteristics, and service life, which are not directly controllable by the manufacturing enterprise. Therefore, limiting the accounting scope to the "cradle to gate" stage at the production end more objectively and scientifically reflects the carbon emission level of the product manufacturing process and is consistent with domestic and international carbon footprint accounting standards for building materials.

[0089] (ii) Collect activity level data: Collect primary data on raw and auxiliary material usage, energy consumption (electricity, fossil fuels, biomass, general industrial solid waste fuels), and in-plant transportation volume and distance according to production process.

[0090] like Figure 2 As shown, the production process of the present invention based on the preparation of recycled ceramsite products from multi-source solid waste mainly includes a pretreatment system #1 for construction solid waste, a pretreatment system #2, RDF / SRF preparation, a gasification furnace, and a ceramsite kiln production system. Each link involves the consumption of raw and auxiliary materials and the use of energy during operation.

[0091] First, the pretreatment system #1 is used to crush, sort and screen decoration waste, demolition waste, and general industrial solid waste, separating metals, inert aggregates and slag. Light combustibles enter the pretreatment system #2, and the undersize soil is sent to the ceramsite production line as raw material for synthetic ceramsite. This process mainly consumes electricity.

[0092] Second, the pretreatment system #2 crushes, presses, and sorts lightweight combustibles and mushroom sticks to form combustible fuel (RDF / SRF), which also consumes electrical energy.

[0093] Third, the gasifier solid waste energy power station gasifies RDF / SRF at high temperature to generate syngas that can be used in ceramsite kilns, and can also supplement fossil energy as a stable fuel as needed.

[0094] Fourth, the ceramsite kiln production line receives raw materials such as slag, sludge, fly ash, and construction waste from the pretreatment system. After batching, granulation, calcination, cooling, and screening, it forms green recycled ceramsite. This stage is an energy-intensive process, mainly consuming electricity and fuel (from syngas from the gasifier), and producing flue gas that is treated to meet emission standards.

[0095] (iii) Determine the greenhouse gas emission factors of raw materials, energy and transportation, and match them with GB / T24067—2024, ISO / TS14067:2013, PAS2050:2011 standards, IPCC2006 guidelines and China Product Life Cycle Database.

[0096] The types of greenhouse gas emissions include: CO2 emitted from the production of raw and auxiliary materials; CO2 generated during the transportation of raw and auxiliary materials and finished products within the factory; indirect CO2 emissions caused by electricity used in various production processes; CO2 generated from the combustion of fossil fuels; CH4 and N2O generated during the gasification and combustion of biomass fuels (with its CO2 treated as net zero); and CO2, CH4, and N2O generated from the gasification and combustion of fossil fuels in general industrial solid waste.

[0097] (iv) Calculate the greenhouse gas emissions for the raw material acquisition stage, production and processing stage, and on-site transportation stage, and convert them into carbon dioxide equivalent (CO2e) in a unified manner; summarize the life cycle greenhouse gas emissions according to formula (1), and convert them into unit product carbon footprint value according to formula (2). The calculation formula is as follows:

[0098]

[0099] Where E CHG GWP (Gross Potassium Wheatstone) represents the total CO2 emissions over the life cycle of expanded clay aggregates, expressed in kgCO2. i C represents the GWP value of the i-th type of greenhouse gas; rawCO2 emissions during the raw material acquisition stage, expressed in kgCO2; C prod CO2 emissions during the production and processing stage, expressed in kgCO2; C trans This represents CO2 emissions during the transportation phase, expressed in kgCO2.

[0100] CFP CHG =E CHG / G product ……(2),

[0101] CFP CHG The carbon footprint of expanded clay products is expressed in kgCO2 / m³. 3 E CHG G represents the total CO2 emissions over the life cycle of expanded clay aggregate, expressed in kgCO2. product Total output product quantity, in meters (m). 3 .

[0102] In this invention, greenhouse gas emissions during the raw material acquisition stage consist of emissions from raw material production and emissions from raw material transportation, calculated as shown in equation (3):

[0103] C raw =C material +C raw-trans ……(3),

[0104] Where C raw This refers to the carbon dioxide equivalent emissions during the raw material acquisition stage, expressed in kgCO2. material Emissions from the production of raw and auxiliary materials, expressed in kgCO2; C raw-trans This represents the emissions from the transportation of raw and auxiliary materials from the production site to the ceramsite plant, expressed in kgCO2.

[0105] The emissions from the production of raw and auxiliary materials are calculated using the following formula:

[0106]

[0107] Where EF i denoted as the greenhouse gas emission factor for the i-th raw material, expressed in kgCO2 / t (or in units consistent with the activity data used); AD i The activity data for the i-th type of raw and auxiliary material is in t (or in units matching the emission factor).

[0108] When the raw materials used are byproducts or solid waste from upstream processes, according to GB / T24067—2024, greenhouse gas emissions from the upstream production stage are not counted repeatedly in this product system, and C is taken as... material =0.

[0109] The emissions from the transportation of raw and auxiliary materials are calculated using the following formula:

[0110]

[0111] Where M supply，i D represents the transport volume of the i-th raw material / auxiliary material, in tons (t). distance，i The corresponding transport distance is expressed in km; T emission，i The unit freight emission factor is the transportation mode used, expressed in kgCO2 / (t·km).

[0112] In this invention, the emissions during the product production stage include four parts: electricity consumption, biomass gasification combustion, general industrial solid waste gasification combustion, and fossil fuel combustion. Their calculation relationship is shown in equation (6):

[0113] C prod =C elec +C bio +C isw +C fossil ……(6),

[0114] Where C prod CO2 emissions during the production and processing stage, expressed in kgCO2; C elec CO2 emissions from electricity consumption during the production and processing stage, expressed in kgCO2; C bio Carbon dioxide emissions related to biomass gasification combustion, expressed in kgCO2; C isw This refers to the CO2 emissions from the gasification and combustion of general industrial solid waste during the production and processing stage, expressed in kgCO2; C fossil This represents the CO2 emissions caused by the combustion of fossil fuels during the production and processing stage, expressed in kgCO2.

[0115] In this invention, the formula for calculating the CO2 emissions from electricity consumption is shown in (7):

[0116]

[0117] C elec CO2 emissions from electricity consumption during the production and processing stage, expressed in kgCO2; M elec，i This refers to the electricity consumption during the product manufacturing stage, expressed in kWh; M green，i Green electricity offset during the product manufacturing phase, in kWh; CEF elec，i The local greenhouse gas emission factor for electricity, expressed in kgCO2 / kWh; MF mat This represents the percentage of the target product's mass during the production process, expressed in wt%.

[0118] The formula for calculating the mass percentage of the target product during the production process is shown in (8):

[0119]

[0120] Where M target The target product mass produced during the production and processing process, expressed in kg; M total The mass of all products produced during the manufacturing process, expressed in kg.

[0121] In this invention, the CO2 emissions from the biomass gasification combustion only need to consider the N2O and CH4 emissions generated during the combustion process, and the calculation relationship is shown in equation (9):

[0122]

[0123] C bio The carbon dioxide emissions related to biomass gasification combustion are expressed in kgCO2. This refers to the amount of methane (CH4) emissions converted to carbon dioxide during biomass gasification and combustion, expressed in kgCO2. This refers to the amount of nitrous oxide (N2O) emissions converted into carbon dioxide emissions during biomass gasification and combustion, expressed in kgCO2.

[0124] The formula for calculating the amount of methane (CH4) emissions converted to carbon dioxide during the biomass gasification and combustion process is shown in (10):

[0125]

[0126] Fuel is the amount of methane (CH4) emissions converted to carbon dioxide during biomass gasification and combustion, expressed in kgCO2. bio，i NCV represents the consumption of biomass fuel of type i, in kg. bio，i The lower heating value of the i-th type of biomass fuel is expressed in TJ / kg. The emission factor for methane (CH4) from biomass combustion in category i is expressed in kg / TJ. This represents the 100-year global warming potential of methane (CH4), expressed in t·CO2e / t·CH4; it is typically taken as 27.9 according to the "GB_T24067-2024 Requirements and Guidelines for Quantifying the Carbon Footprint of Greenhouse Gas Products".

[0127] The formula for calculating the carbon dioxide emissions converted from nitrous oxide (N2O) emissions during the biomass gasification combustion process is shown in (11): , This refers to the emission of nitrous oxide (N2O) during biomass gasification combustion, converted to carbon dioxide equivalent, expressed in kgCO2. bio，i NCV represents the consumption of biomass fuel of type i, in kg. bio，i The lower heating value of the i-th type of biomass fuel is expressed in TJ / kg. The emission factor for nitrous oxide (N2O) from the combustion of biomass of type i is expressed in kg / TJ. The global warming potential of nitrous oxide (N2O) over the next 100 years is expressed in t·CO2e / t·CH4; it is typically taken as 273 according to the "GB_T24067-2024 Requirements and Guidelines for Quantifying the Carbon Footprint of Greenhouse Gas Products".

[0128] In this invention, the CO2 emissions caused by the gasification and combustion of general industrial solid waste during the production and processing stage include direct CO2 emissions, methane (CH4) emissions, and nitrous oxide (N2O) emissions, as shown in formula (12):

[0129]

[0130] Where C isw This represents the total CO2 emissions from the gasification and combustion of general industrial solid waste during the production and processing stage, expressed in kgCO2. This refers to the direct CO2 emissions generated from the gasification and combustion of general industrial solid waste within the project boundary, expressed in kgCO2. This refers to the amount of methane (CH4) emissions converted into carbon dioxide emissions during the combustion process of general industrial solid waste gasification, expressed in kgCO2. This refers to the amount of nitrous oxide (N2O) emissions converted into carbon dioxide emissions during the combustion process of general industrial solid waste gasification, expressed in kgCO2.

[0131] The formula for calculating the direct CO2 emissions generated by the gasification and combustion of general industrial solid waste during the production and processing stage is shown in (13):

[0132]

[0133] in Q represents the total CO2 emissions from the combustion of general industrial solid waste within the project boundary, expressed in kgCO2. isw，i The mass of general industrial solid waste supplied is expressed in kg; OF i Combustion efficiency for general solid waste type i, in %; FCC i Total carbon content in general industrial solid waste, expressed as a percentage (%); FFC i The fossil carbon content in general industrial solid waste, expressed as a percentage.

[0134] The formula for calculating the amount of methane (CH4) emissions converted to carbon dioxide emissions during the combustion process of general industrial solid waste gasification is shown in (14):

[0135]

[0136] in Q represents the amount of methane (CH4) emissions converted to carbon dioxide during the combustion process of general industrial solid waste gasification, expressed in kgCO2. isw，i The quantity of general industrial solid waste i supplied, in kg; The methane (CH4) emission factor is the emission factor of general industrial solid waste after gasification and combustion, expressed in g / t. The 100-year global warming potential of methane (CH4) is expressed in t·CO2e / t·CH4.

[0137] The formula for converting nitrous oxide (N2O) emissions into carbon dioxide emissions during the combustion process of general industrial solid waste gasification is shown in (15):

[0138]

[0139] in Q represents the emission of nitrous oxide (N2O) during the combustion process of general industrial solid waste gasification, converted to carbon dioxide equivalent, with the unit being kgCO2; isw，i The quantity of general industrial solid waste i supplied, in kg; The emission factor of nitrous oxide (N2O) during the combustion process of general industrial solid waste gasification is expressed in g / t. The 100-year global warming potential of nitrous oxide (N2O) is expressed in t·CO2e / tN2O.

[0140] In this invention, the CO2 emissions generated by the combustion of fossil fuels during the product production stage are calculated using the formula shown in (16):

[0141]

[0142] Where C fossil The CO2 emissions from burning fossil fuel type i are expressed in kg CO2. i For each type of fossil fuel, the consumption amount used for fuel combustion is specified, expressed in kg for solid or liquid fuels and in 10,000 Nm³ for gaseous fuels. 3 Unit: CC i The carbon content of fossil fuel type i is expressed in tons of carbon per ton of fuel for solid and liquid fuels, and in tons of carbon per 10,000 Nm³ for gaseous fuels. 3 Unit: OF idenoted as the carbon oxidation rate of fossil fuel type i, with a value ranging from 0 to 1.

[0143] The formula for calculating the carbon content of the fossil fuel is shown in (17):

[0144] CC i =NCV i ×EF i ……(17),

[0145] NCV i The lower heating value of fossil fuel type i is expressed in megajoules (GJ) / ton for solid and liquid fuels, and in GJ / 10,000 Nm³ for gaseous fuels. 3 Units; EF i The carbon content per unit calorific value of fossil fuel type i is expressed in tons of carbon per gram (gJ).

[0146] In this invention, the CO2 generated during the transportation of the finished product within the factory area is calculated as shown in equation (18):

[0147]

[0148] Where C trans Carbon emissions from transporting finished products to the warehouse, kgCO2; M supply，i D represents the transport volume of the i-th type of finished product, with units depending on the type of raw material; distance，i T represents the transportation distance of the i-th type of finished product, in km; emission，i The carbon emission factor for transportation is expressed in kgCO2 / (t·km).

[0149] II. Specific application examples are as follows:

[0150] The project involves the construction of a new recycled ceramsite production line with an annual production capacity of approximately 210,000 m³. 3 (bulk density approximately 450 kg / m³) 3 The project's disposal capacity includes: approximately 200,000 tons / year of construction waste and mud (including covering waste, washed sand sediment, sludge, contaminated soil, etc.), 100,000 tons / year of demolition waste, 50,000 tons / year of renovation waste, 1,000 tons / year of bulky waste, 3,000 tons / year of garden waste, 26,400 tons / year of sludge (60% sand content), 4,000 tons / year of general industrial solid waste (combustible materials), 30,000 tons / year of mushroom substrate and other biomass, and 50,000 tons / year of recycled resources.

[0151] 1. Emissions during the raw material acquisition stage.

[0152] 1.1 Emissions during the raw material production stage

[0153] This embodiment statistically analyzes the types and quantities of solid waste raw materials mainly input into the plant during the accounting period, specifically including: 138,298.3 kg of sand washing bottom mud, 111,451.9 kg of construction waste and contaminated soil, 19,133.6 kg of municipal sludge, 22,270 kg of stainless steel ash, and 26,874 kg of pickling waste mud.

[0154] According to the closed-loop / open-loop allocation rules in Appendix D.3 of GB / T24067—2024 Requirements and Guidelines for Quantifying the Carbon Footprint of Greenhouse Gas Products, if the input raw materials are by-products or solid wastes from upstream processes, the greenhouse gas emissions from their production stage should not be repeatedly included in the downstream product system. Therefore, the emission factors EF for various raw materials should be calculated separately. i All values ​​are set to 0. The activity level data (AD) for each type of raw material in the table are then used. i Substituting into equation (4), the calculation is as follows:

[0155] C material =(138298.3×0)+(111451.9×0)+(19133.6×0)+(22270×0)+(26874×0)=0kgCO2.

[0156] 1.2 Emissions during the transportation of raw and auxiliary materials.

[0157] The transportation distance for washed sand sediment, construction waste and contaminated soil, municipal sludge, stainless steel ash and pickling waste sludge is 50km, and medium-sized trucks are used for transportation. The emission factor is taken from the IPCC recommended value of 0.042kgCO2 / (t·km). The carbon emissions during the transportation of raw and auxiliary materials are calculated according to formula (5) as follows:

[0158] C raw-trans =(138.2983+111.4519+19.1336+22.27+26.874)×50×0.042=668.88kgCO.

[0159] 2. Emissions during the product manufacturing stage.

[0160] 2.1 Electricity consumption emissions.

[0161] Power consumption of each system: Pretreatment system #1 = 2,528,196 kWh (MF) mat =0.156), Pretreatment system #2 = 6,459,763.2 kWh (MF) mat =1), Gasifier = 1,141,600 kWh (MF) mat =1), ceramsite kiln and flue gas purification = 22,004,352 kWh (MF) mat =1), others = 4,271,040 kWh (MF) mat=1). Total electricity consumption was 36,404,951.2 kWh. Regional electricity emission factor CEF elec，i = 0.5153 kg CO / kWh.

[0162] Among them, the MF of preprocessing system #1 mat =0.156, all other systems are 1.000. Green electricity = 3,037,600 kWh, allocated according to the electricity consumption ratio of each system: Green electricity allocation is as follows:

[0163]

[0164] The carbon emissions from the electricity sector are:

[0165] C elec = [(2528196-3037600×2528196 / 36404951.2)×0.5153×0.156]

[0166] +[(6459763.2-3037600×6459763.2 / 36404951.2)×0.5153×1]

[0167] +[(1141600-3037600×1141600 / 36404951.2)×0.5153×1]

[0168] +[(22004352-3037600×22004352 / 36404951.2)×0.5153×1]

[0169] +[(4271040-3037600×4271040 / 36404951.2)×0.5153×1]

[0170] = 16,186,395.48 kg CO2.

[0171] 2.2 Emissions from biomass gasification combustion.

[0172] In this embodiment, the annual consumption of biomass fuel is 10,667,000 kg, with an average lower heating value of 1,466,156 TJ / kg. Based on the operating parameters and combustion characteristics of the gasification system, the emission factors and global warming potential values ​​recommended in the IPCC 2006 National Greenhouse Gas Inventory Guidelines are used for calculation: methane (CH4) emission factor is 30 kg / TJ; methane (CH4) global warming potential is 27.9; nitrous oxide (N2O) emission factor is 4 kg / TJ; nitrous oxide (N2O) global warming potential is 273.

[0173] Calculate the emissions of methane and nitrous oxide converted to carbon dioxide equivalents using equations (10) and (11), respectively:

[0174]

[0175]

[0176] Therefore, the total CO2 emissions from biomass gasification combustion can be obtained:

[0177]

[0178] 2.3 Emissions from gasification and combustion of general industrial solid waste

[0179] In this embodiment, the emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) produced by its combustion are considered. Relevant parameters are as follows: general industrial solid waste consumption is 16,000 t; methane emission factor is 5.4 g / t, global warming potential is 27.9; nitrous oxide emission factor is 8.38 g / t, global warming potential is 273; total carbon content is 42.04%, fossil carbon content is 60%, and combustion efficiency is 98%.

[0180] Based on the greenhouse gas emission formula for the gasification combustion stage, the calculation results are as follows:

[0181]

[0182] C isw =145,021.18+2,410.56+36,603.84=145,411,32.80kgCO2.

[0183] 2.4 Fossil fuel emissions.

[0184] According to monitoring and energy consumption records, gasoline consumption was 22,000 kg and diesel consumption was 46,000 kg. The characteristic parameters of the two fuels are as follows: gasoline carbon content: 0.84672; diesel carbon content: 0.875266; carbon oxidation rate of both is 98%; lower heating value of gasoline is 44.800 GJ / t, and lower heating value of diesel is 43.330 GJ / t; carbon content per unit calorific value of gasoline is 0.0189 tC / GJ, and carbon content per unit calorific value of diesel is 0.0202 tC / GJ.

[0185] According to the fossil fuel combustion emission formula in the "Guidelines for Greenhouse Gas Emission Accounting Methods and Reporting of Enterprises in Other Industrial Sectors":

[0186]

[0187] Therefore, considering electricity consumption during the production phase, emissions from biomass gasification combustion, emissions from general industrial solid waste gasification combustion, and emissions from fossil fuels, the CO2 emissions during the production phase are:

[0188] C prod =16,186,395.48 + 301,685.66 + 145,411,32.80 +

[0189] 211,611.67=31,240,825.61kgCO2.

[0190] 3. Product transportation emissions.

[0191] The transport distance for recycled ceramsite is 1 km, the transport volume is 94,500 t, the transport method is medium-sized trucks, and the emission factor is taken from the IPCC recommended value of 0.042 kg CO2 / (t·km). The carbon emissions during the transport stage are calculated according to formula (18) as follows:

[0192] C trans =94,500×1×0.042=3,969kgCO2.

[0193] 4. Carbon footprint calculation.

[0194] Based on the aforementioned calculations, the carbon emissions during the raw material transportation stage are 668.88 kg CO2; the carbon emissions during the production and processing stage are 31,240,825.61 kg CO2; and the carbon emissions during the product transportation stage are 3,969 kg CO2. Therefore, the total carbon emissions of the system are calculated as follows:

[0195] E CHG =668.88 + 31,240,825.61 + 3,969 = 31,245,463.49 kg CO2, based on an annual output of 210,000 m³ of recycled ceramsite. 3 The carbon footprint per unit product is calculated as follows:

[0196]

[0197] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A method for calculating the carbon footprint of recycled ceramsite prepared from multi-source solid waste, characterized in that: Includes the following steps: (a) Determine the functional units and system boundaries; (ii) Collect preliminary data on raw and auxiliary material usage, energy consumption, and in-plant transportation volume and distance according to the production process; (iii) Determine the greenhouse gas emission factors of raw materials, energy and transportation; (iv) Calculate greenhouse gas emissions for the raw material acquisition stage, production and processing stage, and on-site transportation stage by stage; summarize the life cycle greenhouse gas emissions according to formula (1), and convert them into unit product carbon footprint value according to formula (2). The calculation formula is as follows: Where E CHG Total CO2 emissions over the life cycle of expanded clay aggregate; GWP i C represents the GWP value of greenhouse gas type i; raw CO2 emissions during the raw material acquisition stage; C prod CO2 emissions during the production and processing stage; C trans CO2 emissions during the transportation phase; CFP CHG =And CHG / G product ……(2), CFP CHG Carbon footprint of expanded clay products; E CHG This represents the total CO2 emissions over the lifecycle of expanded clay aggregate; G product Total output product quantity.

2. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 1, characterized in that: In step (1), the system boundary is defined as: from cradle to gate, covering the raw material acquisition stage, the product manufacturing stage, and the on-site transportation stage; The raw material acquisition stage includes two sub-processes: raw material production and transportation. The product manufacturing stage described above covers the entire production process from raw material intake to finished ceramsite product delivery, including: (1) Construction waste pretreatment: sorting, crushing and screening the construction waste and slag entering the plant; (2) Separation of metals / slag and extraction of light and heavy materials: Separate recyclable metals from inert slag and extract recycled aggregates, combustible light materials and recycled resources; (3) Combustible gasification for energy supply: general industrial solid waste and biomass are gasified to generate combustible gas for energy supply to the production system. (4) Ceramsite production: including raw material proportioning, granulation, calcination, cooling and conveying processes, to form recycled ceramsite products that meet performance requirements; The aforementioned on-site transportation stage refers to the short-distance transport of materials and products between different processes within the factory area and their warehousing.

3. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 1, characterized in that: In step (iii), the types of greenhouse gas emissions include: CO2 emitted from the production of raw and auxiliary materials; CO2 generated during the transportation of raw and auxiliary materials and finished products within the factory; indirect CO2 emissions caused by electricity used in various production processes; CO2 generated from the combustion of fossil fuels; CH4 and N2O generated during the gasification and combustion of biomass fuels; and CO2, CH4, and N2O generated from the gasification and combustion of fossil fuels in general industrial solid waste.

4. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 1, characterized in that: In step (iv), the greenhouse gas emissions in the raw material acquisition stage consist of emissions from the production of raw and auxiliary materials and emissions from the transportation of raw and auxiliary materials, and the calculation relationship is shown in equation (3): C raw =C material +C raw-trans ……(3), Where C raw C represents the carbon dioxide equivalent emissions during the raw material acquisition stage. material Emissions from the production of raw and auxiliary materials; C raw-trans This refers to the emissions from the transportation of raw and auxiliary materials from the point of origin to the ceramsite plant; The emissions from the production of raw and auxiliary materials are calculated using the following formula: Where EF i AD is the greenhouse gas emission factor of the i-th raw and auxiliary material; i For the activity data of the i-th type of raw and auxiliary material; The emissions from the transportation of raw and auxiliary materials are calculated using the following formula: Where M supply，i D represents the transportation volume of the i-th type of raw material; distance，i For the corresponding transportation distance; T emission，i This represents the unit freight emission factor for the mode of transportation used.

5. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 1, characterized in that: The emissions during the product production stage include four parts: electricity consumption, biomass gasification combustion, general industrial solid waste gasification combustion, and fossil fuel combustion. Their calculation relationship is shown in equation (6): C prod =C elec +C bio +C isw +C fossil ……(6), Where C prod CO2 emissions during the production and processing stage; C elec CO2 emissions from electricity consumption during the production and processing stage; C bio Carbon dioxide emissions related to biomass gasification combustion; C isw This refers to the CO2 emissions from the gasification and combustion of general industrial solid waste during the production and processing stage; C fossil This refers to the CO2 emissions caused by the combustion of fossil fuels during the production and processing stage.

6. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 5, characterized in that: The formula for calculating CO2 emissions from electricity consumption is shown in (7): C elec CO2 emissions from electricity consumption during the production and processing stage; M elec，i M represents the electricity consumption during the product manufacturing stage. green，i Green electricity offset during the product manufacturing phase; CEF elec，i Local greenhouse gas emission factor for electricity; MF mat The percentage of the target product's quality during the production process; The formula for calculating the mass percentage of the target product during the production process is shown in (8): Where M target The target product quality produced during the manufacturing process; M total The quality of all products produced during the manufacturing and processing process.

7. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 5, characterized in that: The CO2 emissions from biomass gasification combustion only need to consider the N2O and CH4 emissions generated during the combustion process, and the calculation relationship is shown in equation (9): C bio Carbon dioxide emissions related to biomass gasification and combustion; This refers to the amount of methane emissions converted into carbon dioxide emissions during the biomass gasification and combustion process. This refers to the amount of nitrous oxide emissions converted into carbon dioxide emissions during biomass gasification and combustion. The formula for calculating the amount of methane emissions converted to carbon dioxide during the biomass gasification and combustion process is shown in (10): Fuel is the amount of methane emissions converted to carbon dioxide during biomass gasification and combustion. bio，i NCV represents the consumption of biomass fuel of type i; bio，i For the lower heating value of the i-th type of biomass fuel, ; The methane emission factor for biomass combustion of type i; The 100-year global warming potential of methane; The formula for calculating the amount of nitrous oxide emissions converted to carbon dioxide during the biomass gasification combustion process is shown in (11): This refers to the emission of nitrous oxide during biomass gasification combustion, converted to carbon dioxide equivalents. bio，i NCV represents the consumption of biomass fuel of type i; bio，i The lower heating value of the i-th type of biomass fuel; The emission factor for nitrous oxide from biomass combustion of type i; This represents the global warming potential of nitrous oxide.

8. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 5, characterized in that: The CO2 emissions from the gasification and combustion of general industrial solid waste during the production and processing stage include direct CO2 emissions, methane emissions, and nitrous oxide emissions, as shown in formula (12): Where C isw This refers to the total CO2 emissions caused by the gasification and combustion of general industrial solid waste during the production and processing stage. This refers to the direct CO2 emissions generated from the gasification and combustion of general industrial solid waste within the project boundary. This refers to the amount of methane emissions converted into carbon dioxide emissions during the combustion process of general industrial solid waste gasification. This refers to the amount of nitrous oxide emissions converted into carbon dioxide emissions during the combustion process of general industrial solid waste gasification.

9. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 8, characterized in that: The formula for calculating the direct CO2 emissions generated by the gasification and combustion of general industrial solid waste during the production and processing stage is shown in (13): in Q represents the total CO2 emissions from the combustion of general industrial solid waste within the project boundary; isw，i For the quality of general industrial solid waste i supplied; OF i Combustion efficiency for general solid waste type i; FCC i Total carbon content in general industrial solid waste; FFC i The fossil carbon content in general industrial solid waste; The formula for calculating the amount of methane emissions converted to carbon dioxide emissions during the combustion process of general industrial solid waste gasification is shown in (14): in Q represents the amount of methane emissions converted to carbon dioxide during the combustion process of general industrial solid waste gasification; isw，i The quantity of general industrial solid waste i supplied; The methane emission factor is the methane emission factor in the combustion process after gasification of general industrial solid waste. The global warming potential of methane; The formula for calculating the carbon dioxide emissions from the combustion of general industrial solid waste after gasification is shown in (15): in This refers to the emission of nitrous oxide during the combustion process of general industrial solid waste gasification, converted into carbon dioxide equivalents; Q isw，i The quantity of general industrial solid waste i supplied; Nitrous oxide emission factor during the combustion process of general industrial solid waste gasification; This represents the global warming potential of nitrous oxide.

10. The carbon footprint accounting method for preparing recycled ceramsite based on multi-source solid waste according to claim 5, characterized in that: The CO2 emissions generated by the combustion of fossil fuels during the product production stage are calculated using the formula shown in (16): Where C fossil CO2 emissions from the combustion of fossil fuel type i; AD i Specify the consumption amount of fossil fuel i used for fuel combustion; CC i The carbon content of fossil fuel type i; OF i The carbon oxidation rate of fossil fuel type i; The formula for calculating the carbon content of the fossil fuel is shown in (17): CC i =NCV i ×EF i ……(17), NCV i The lower heating value of fossil fuel type i; EF i Carbon content per unit calorific value of fossil fuel type i; The calculation relationship for CO2 generated during the transportation of the finished product within the factory area is shown in equation (18): Where C trans Carbon emissions from transporting finished products to warehouses; M supply，i D represents the transport volume of the i-th type of finished product; distance，i T represents the transportation distance of the i-th type of finished product; emission，i Carbon emission factors in the form of transportation.

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