Carbon emission accounting method for the whole process of recycling waste wood templates and remanufacturing artificial boards

Abstract

This invention discloses a method for calculating the carbon emissions of the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels. The method calculates the total mass of waste wooden formwork and the mass of recyclable wooden formwork based on the building area of ​​the demolition project. It calculates the carbon emissions during the demolition of recyclable wooden formwork and the carbon emissions during the transportation of recyclable wooden formwork from the demolition site to the recycling plant. It also calculates the carbon emissions during the processing at the recycling plant, the carbon emissions during the transportation of processed wood from the recycling plant to the production plant, the carbon emissions of supplementary materials, and the carbon emissions during the production of processed wood. Furthermore, it calculates the carbon emissions of recycled engineered wood panels processed using traditional methods, constructs a carbon emission difference calculation model between traditional and recycling processes, and quantifies the total carbon emission savings from replacing virgin wood with waste wooden formwork. This invention can accurately calculate the carbon emissions of the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels in specific projects, covering all scenarios of wooden formwork recycling in the construction industry.

Description

Technical Field

[0001] This invention relates to the field of carbon emission accounting technology, and in particular to a method for carbon emission accounting of the entire process of recycling waste wooden formwork into artificial boards. Background Technology

[0002] The theory of carbon emissions throughout the entire life cycle of buildings encompasses the production, design, construction, use, and even dismantling of building materials. For the production and use stages, which account for the largest share of carbon emissions, multi-dimensional research findings have been developed. However, research on the large-scale application of dismantled and reused building materials remains limited and lacks in-depth exploration.

[0003] For example, patent publication number CN111687960A, entitled "A Method for Recycling Waste Wooden Formwork in Construction," describes a patented technology that utilizes waste wooden formwork for resource recovery. This involves surface treatment, cutting, fumigation, and core board splicing to achieve recycling, resulting in energy conservation and environmental protection by saving timber resources and reducing pollution. Another example is patent publication number CN103104088A, entitled "A Method for Making Recycled Building Boards Using Waste Construction Formwork." Using waste formwork as raw material, this patent optimizes the molding process of the recycled product. It improves key processes such as nail removal, width and thickness limiting sawing, side gluing with staggered joints, horizontal core board splicing, and high-temperature, high-pressure lamination. The resulting recycled building board features high strength and high modulus, significantly increasing the reuse rate of waste formwork while reducing the environmental pressure from incineration and landfill.

[0004] Although the aforementioned patents involve the recycling and processing technology of waste wooden formwork, they still follow the traditional methods of incineration and landfill to deal with building carbon emissions. There is still a lack of relevant research on establishing carbon emission accounting and quantifying emission reduction benefits for the entire process of recycling and remanufacturing artificial boards. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies that lack carbon emission accounting models and quantitative systems for emission reduction benefits in the entire process of recycling and remanufacturing of engineered wood products. The proposed method for carbon emission accounting of the entire process of recycling and remanufacturing of waste wood templates into engineered wood products calculates and statistically analyzes the carbon emission inventory of key operations such as crushing, drying, gluing, and hot pressing, and compares and analyzes the carbon footprint of recycled engineered wood products with that of virgin engineered wood products, thus filling a technological gap in the industry.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A comprehensive carbon emission accounting method for the entire process of recycling waste wooden formwork into engineered wood panels, including the following:

[0008] The total mass of waste wood formwork and the mass of recyclable wood formwork are calculated based on the building area of ​​the demolition project. The carbon emissions during the demolition of recyclable wood formwork and the carbon emissions during the transportation of recyclable wood formwork from the demolition site to the recycling plant are also calculated.

[0009] The carbon emissions from the recycling process are calculated, including the carbon emissions from transporting the treated wood from the recycling plant to the production plant, the carbon emissions from supplementary materials, and the carbon emissions from the production process of the treated wood.

[0010] The carbon emissions from processing recycled engineered wood panels using traditional processes are calculated. A carbon emission difference calculation model between traditional and recycled processes is constructed to quantify the total carbon emission savings from replacing virgin wood with waste wood formwork.

[0011] Furthermore, the total mass of waste wood formwork and the mass of recyclable wood formwork are calculated based on the building area of ​​the demolition project:

[0012] Considering natural wear and tear during the lifespan of the wooden formwork, the total mass of discarded wooden formwork and the mass of recyclable wooden formwork are calculated using the following formula:

[0013]

[0014]

[0015] In the above formula, This indicates the total mass of the dismantled waste wooden formwork. The building area to be demolished. This refers to the initial amount of wooden formwork used per unit area. Waste rate of wooden formwork; This indicates the quality of recyclable waste wood formwork. Indicates the recyclable percentage of wooden formwork. This indicates the loss rate caused by tearing of wooden formwork and residual nails during the dismantling process;

[0016] The calculation of carbon emissions during the dismantling of recyclable wood formwork is as follows: Carbon emissions are generated during the dismantling of recyclable wood formwork due to both mechanical crushing and cutting, and manual operation.

[0017]

[0018] In the formula, This indicates the total carbon emissions during the removal of recyclable wood formwork. This indicates carbon emissions during the use of machinery. This represents the carbon emissions from the labor metabolism of demolition workers. This indicates the total carbon emissions from processing non-recyclable wood formwork;

[0019] The carbon emissions from the transportation of the recyclable wood molds from the demolition site to the recycling plant are calculated using the following formula:

[0020]

[0021] In the formula, This represents the carbon emissions during the transportation and processing of recyclable wood formwork, where D represents the average transportation distance. This indicates the energy consumption per unit mass of diesel truck during transportation. This indicates the carbon emission factor of diesel fuel.

[0022] Furthermore, when calculating the carbon emissions during the dismantling of recyclable wood formwork, the carbon emissions generated by mechanical crushing and cutting during the dismantling process are calculated using the following formula:

[0023]

[0024] In the formula, Indicates the rated power of the electric machinery. Indicates the operating time of the electric machinery. Indicates the carbon emission factor of electricity. This indicates the fuel consumption of diesel machinery. Indicates the usage of different types of machinery;

[0025] The carbon emissions from the labor metabolism of demolition workers are calculated as follows:

[0026] In the formula, Indicates the number of demolition workers. This indicates the average working time per person. This represents the average metabolic rate per person. Indicates the carbon emission factor of food;

[0027] The total carbon emissions from the treatment of non-recyclable wood formwork are calculated using the following formula:

[0028]

[0029] In the formula, This indicates the carbon emissions during the processing of non-recyclable wood formwork. This indicates carbon emissions during the transportation of non-recyclable wooden formwork.

[0030] Furthermore, the carbon emissions from the recycling process at the recycling plant are calculated as follows: After the recyclable wooden formwork is transported to the recycling plant and undergoes crushing, drying, and chemical treatment, the resulting carbon emissions are expressed using the following formula:

[0031]

[0032] In the formula, This indicates the carbon emissions throughout the entire processing phase of the recycling plant. This indicates the carbon emissions from crushing wooden formwork into qualified waste. This indicates the carbon emissions from drying wood templates into qualified waste material. This refers to the carbon emissions from transporting recyclable wooden formwork to a recycling plant for chemical treatment.

[0033] The carbon emissions from transporting treated timber from the recycling plant to the production plant are calculated using the following formula.

[0034]

[0035] In the formula, This indicates the carbon emissions during the transportation of processed timber. This represents the amount of wood formwork consumed after crushing, and D represents the average transportation distance. This indicates the energy consumption per unit mass of diesel truck during transportation. Indicates the carbon emission factor of diesel fuel;

[0036] The carbon emissions from the processed wood production process are calculated using the following formula:

[0037]

[0038] In the formula, This indicates that the carbon emissions from processing recycled engineered wood panels in factories using traditional processes are being addressed. This indicates the carbon emissions during the hot pressing process. This indicates the carbon emissions during the adhesive application process. This indicates carbon emissions during the cooling process. This indicates the carbon emissions from the trimming and sanding processes.

[0039] Furthermore, the carbon emissions from crushing the wooden formwork into qualified scrap are... The calculation formula is as follows:

[0040]

[0041] In the formula, This indicates the rated power of the crusher. This indicates the time required to crush a unit mass of wooden formwork. This indicates the quality of recyclable waste wood formwork. Indicates the carbon emission factor of electricity;

[0042] The carbon emissions from drying the wood templates into qualified scrap are as follows. The calculation formula is as follows:

[0043]

[0044] In the formula, Indicates the rated power of the drying equipment. This indicates the drying time per unit mass of wood chips. This indicates the amount of auxiliary heat source consumed during the drying process. Indicates the carbon emission factor of natural gas;

[0045] Carbon emissions from transporting recyclable wood templates to a recycling plant for chemical treatment The calculation formula is as follows:

[0046]

[0047] In the formula, This indicates the carbon emission factor from the production and use of preservatives. This indicates the amount of chemical reagents consumed per unit mass of wood chips. This indicates the carbon emission coefficient from the trace decomposition of wood fibers during the treatment process.

[0048] Furthermore, the carbon emissions from the hot pressing process are expressed as follows:

[0049]

[0050]

[0051] In the formula, This indicates the total consumption of wood scraps and logs after the wood templates are crushed for the production of engineered wood products. This indicates the amount of raw timber scraps that need to be replenished. This indicates the amount of wood templates consumed after being broken up; This indicates the rated power of the multi-layer hot press. This indicates the time required for hot pressing a unit mass of recycled board. Indicates the carbon emission factor of electricity;

[0052] The carbon emissions from the sizing process are represented as follows:

[0053]

[0054]

[0055]

[0056] In the formula, This indicates the quality of the adhesive used in the application process. Indicates the carbon emission factor of adhesives. This indicates the quality of the engineered wood product after hot pressing. This indicates the mass ratio of adhesive to the mass of the engineered wood product after hot pressing. This indicates the total mass loss rate from scrap to engineered wood products;

[0057] The carbon emissions from the cooling process are represented as follows:

[0058]

[0059] In the formula, Indicates the rated power of the cooling equipment. This indicates the time required to cool a unit mass of engineered wood panel after hot pressing. Indicates the carbon emission factor of electricity. This indicates the quality of the engineered wood panel after gluing.

[0060] The carbon emission calculation formula for the trimming and sanding process is as follows:

[0061]

[0062]

[0063] In the above formula, This indicates the rated power of the trimming machine. This indicates the time it takes for the engineered wood panel to cool after the trimmed unit mass is removed. This indicates the rated power of the sander. This indicates the time required for a unit mass of sanded engineered wood panel to cool. This indicates the quality of the engineered wood panel after cooling. This indicates the mass loss rate during the cooling process.

[0064] Furthermore, the calculation formula for the carbon emission accounting of the supplementary material is as follows:

[0065]

[0066]

[0067] In the formula, Indicates the carbon emissions of supplementary materials. This indicates the amount of raw timber scraps that need to be replenished. This indicates the carbon emission factor of producing log wood chips using traditional methods. This indicates the total demand for engineered wood products in secondary use scenarios. This indicates the amount of wood templates consumed after being broken.

[0068] Furthermore, the calculation of carbon emissions from the processing of recycled wood-based panels in traditional process plants includes carbon emissions from three stages: traditional logging, traditional transportation, and traditional production. The calculation formula is as follows:

[0069]

[0070] In the formula, This indicates the carbon emissions from the production of traditional virgin engineered wood panels in conventional factories. This indicates the carbon emissions from electricity consumed during the logging process in traditional methods. This indicates the carbon emissions from diesel fuel consumed during the transportation phase of traditional processes. This represents the total carbon emissions generated by energy consumption and chemical reactions in the traditional production process of engineered wood panels.

[0071] Furthermore, the carbon emissions from electricity consumption during the logging process in the traditional method are calculated using the following formula:

[0072]

[0073] In the formula, This indicates the total volume processed by traditional virgin timber factories. This indicates the carbon emission factor per unit of logging;

[0074] The formula for calculating the carbon emissions of diesel fuel consumed during the transportation stage in the traditional process is as follows:

[0075]

[0076] In the formula, This indicates the average transportation distance from the logging site to the wood-based panel manufacturing plant. This indicates the energy consumption per unit mass of diesel truck during transportation. Indicates the carbon emission factor of diesel fuel;

[0077] The formula for calculating the total carbon emissions from energy consumption and chemical reactions in the traditional process of producing engineered wood panels is as follows:

[0078]

[0079] In the formula, This represents the total electricity required to produce 1 ton of engineered wood panels. Indicates the carbon emission factor of electricity. Indicates the carbon emission factor of adhesives. This indicates the mass ratio of adhesive to the mass of the engineered wood panel after hot pressing.

[0080] Furthermore, the expression for the carbon emission difference calculation model for the traditional process and the regeneration process is as follows:

[0081]

[0082] In the formula, This indicates the carbon emission reduction from using waste wood templates to produce recycled engineered wood panels. This indicates the carbon emissions from the traditional production of engineered wood panels. This indicates the carbon emissions of recycled wood paneling made from waste wood templates.

[0083] Compared with the prior art, the beneficial effects of the present invention are:

[0084] This invention focuses on the carbon emissions and carbon offsetting effects generated during the treatment or recycling of construction waste throughout the building lifecycle. It takes dismantled and discarded wooden formwork as a specific research object, introduces the concept of a wood recycling system, and reconstructs the traditional linear process into a circular development approach for the recycling and reuse of discarded wooden formwork. Furthermore, it calculates the carbon emissions of the entire process of discarded wooden formwork from a carbon emission perspective, constructing a system accounting model. Based on this model, the carbon emissions of the recycling and reprocessing of discarded wooden formwork into engineered wood panels in specific projects can be accurately calculated. This model has good adaptability to different types and service stages of discarded wooden formwork, covering the recycling and reuse scenarios of wooden formwork across the entire construction industry. This invention selects typical discarded wooden formwork products, conducts simulation calculations, and scientifically derives key parameters for carbon emissions in each process, including dismantling, transportation, treatment, manufacturing, and product transportation. In specific engineering applications, by substituting engineering information such as the quality of discarded wooden formwork, transportation distance, and energy efficiency of production equipment, the carbon emissions of its recycling and reprocessing into engineered wood panels can be quickly calculated, facilitating the measurement of the carbon reduction benefits of recycling wooden construction waste. Attached Figure Description

[0085] Figure 1 This is a flowchart comparing the carbon emissions of the traditional process and the regeneration process in this embodiment of the invention. Detailed Implementation

[0086] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the specific embodiments of this invention will be described in detail below with reference to the accompanying drawings. These embodiments are merely preferred examples of this invention, used to aid in understanding the inventive concept, and do not constitute a limitation on the scope of protection.

[0087] Wooden formwork is a core auxiliary material used in concrete pouring and shaping during construction. It is widely used in the construction of beams, slabs, columns, walls, and other structures. However, due to limitations in strength and surface wear, it can typically only be reused 3-5 times, resulting in a huge amount of waste. According to statistics, in 2024, the annual consumption of timber for wooden formwork production in the construction formwork industry was approximately 11.5 million to 12.8 million cubic meters. Calculated based on a comprehensive waste rate of 30%-50%, the annual waste amount was approximately 3.45 million to 6.4 million cubic meters, concentrated in the building demolition stage. It is a typical high-volume recyclable waste in the construction industry.

[0088] Choosing wood formwork as a raw material for recycled engineered wood products stems from several key advantages: First, a stable and abundant resource supply: Wood formwork originates from waste wood formwork, with a large existing stock and smooth recycling channels. Raw materials can be provided without felling new trees, ensuring production. Second, significant cost control advantages: As a recycled raw material, wood formwork has a low purchase price, directly reducing raw material costs. The recycling process eliminates the need for complex pre-treatment of raw materials, reducing processing costs. Third, strong processing adaptability: Wood formwork is mostly made of high-quality softwood, retaining a relatively intact fiber structure, meeting the requirements of engineered wood product manufacturing processes. This results in higher work efficiency and a more stable yield. Fourth, it aligns with environmental protection and policy guidelines: It achieves the recycling of construction waste, recycled raw materials, and engineered wood products, reducing wood waste and landfill volume, conforming to the scientific development concept of green manufacturing.

[0089] This embodiment proposes a method for carbon emission accounting of the entire process of recycling waste wooden formwork into engineered wood panels. The accounting process can be referred to [reference needed]. Figure 1 , Figure 1 This is a flow chart comparing the carbon emissions of traditional and regeneration processes. The method includes the following:

[0090] First, calculate the total mass of waste wood formwork and the mass of recyclable wood formwork based on the building area of ​​the demolition project, calculate the carbon emissions during the demolition of recyclable wood formwork, and calculate the carbon emissions during the transportation of recyclable wood formwork from the demolition site to the recycling plant. This process can be marked as Energy Saving Process A.

[0091] The total mass of waste wood formwork and the mass of recyclable wood formwork are calculated based on the building area of ​​the demolition project.

[0092] Considering natural wear and tear during the service life of wooden formwork, such as tearing during turnover, decay, and failure to meet formaldehyde emission standards, the total mass of discarded wooden formwork is calculated using the following formula:

[0093]

[0094] In the above formula, This indicates the total mass (in tons) of the dismantled waste wooden formwork. The building area to be demolished (unit: square meters). The initial usage of timber formwork per unit area (t / ㎡) is taken as 0.04t / ㎡. The wastage rate of wooden formwork (%) is taken as 15%, which is determined according to the standard "Consumption Quota for Building Construction and Decoration Engineering" (TY 01-31-2015).

[0095] Before recycling wooden formwork, severely damaged pieces and nail-attached fragments must be removed. The recyclable wooden formwork weight is calculated using the following formula:

[0096]

[0097] In the formula, This indicates the mass of recyclable waste wood formwork (unit: tons). The percentage of loss caused by tearing of wooden formwork and residual nails during the dismantling process is 15%. The percentage (%) of recyclable timber formwork is taken as 60%. In engineering practice and industry reports, the recycling rate of timber formwork is usually a range, and its specific value is affected by various factors such as the formwork material, the level of use and maintenance, the project type, and the definition of recycling (whether it is direct reuse, downgraded use, or recycling as a material). Based on multiple studies on the sustainability of building formwork, the recycling rate of timber formwork in actual projects is often estimated to be between 50% and 70%; based on this, this scheme takes a conservative midpoint of 60% as the calculation parameter.

[0098] The carbon emissions during the dismantling of recyclable wood formwork are calculated. Both mechanical crushing and cutting, as well as manual operations, generate carbon emissions during the dismantling process. The calculation formula is as follows:

[0099]

[0100] In the formula, This indicates the total carbon emissions during the removal of recyclable wood formwork. This indicates carbon emissions during the use of machinery. This represents the carbon emissions from the labor metabolism of demolition workers. This indicates the total carbon emissions from processing non-recyclable wood formwork.

[0101] Energy consumption and carbon emissions of typical demolition machinery (hydraulic shears, breaker) are as follows: Demolition operation machinery is required during the demolition process, such as hydraulic shears, handheld electric impact drills, and angle grinders; handling and cleaning machinery, such as loaders, forklifts, and cranes; and auxiliary operation machinery, such as small tracked demolition machines and air compressors.

[0102] Therefore, when calculating the carbon emissions during the dismantling of recyclable wood formwork, the carbon emissions generated by mechanical crushing and cutting during the dismantling process are calculated using the following formula:

[0103]

[0104] In the formula, This indicates the rated power of the electric machinery (unit: kW). Indicates the operating time of electric machinery (unit: hours). Indicates the carbon emission factor of electricity (unit: / kWh), This indicates the fuel consumption of diesel machinery (unit: liters). This indicates the usage of different types of machinery. The rated power of various types of electric machinery can be found in Table 1.

[0105] Table 1 Reference Table of Rated Power for Electric Machinery

[0106]

[0107] The metabolic carbon emissions from demolition workers are the metabolic carbon emissions generated by demolition workers during their work, and the accounting expression is as follows:

[0108]

[0109] In the formula, Indicates the number of demolition workers. This indicates the average working time per person (unit: hours). This represents the average metabolic rate per person (unit: kWh / h). Food carbon emission factor (unit: / kWh);

[0110] The total carbon emissions from processing non-recyclable timber formwork (such as severely damaged or nailed sections) are calculated using the following formula:

[0111]

[0112] In the formula, This indicates the carbon emissions during the processing of non-recyclable wood formwork. This indicates carbon emissions during the transportation of non-recyclable wooden formwork.

[0113] Non-recyclable wood formwork is further categorized by its disposal method: landfill / incineration.

[0114]

[0115]

[0116]

[0117] In the formula, This indicates the total mass (in tons) of non-recyclable waste wooden formwork. Carbon emissions from the landfill disposal of timber formwork (unit: ), This indicates the carbon emission factor per unit of wood formwork landfill (unit: / t), This indicates the carbon emissions from the incineration of wood formwork (unit: ), This indicates the carbon emission factor per unit of wood formwork incineration (unit: / t).

[0118] The transportation of wooden formwork from the demolition site to the recycling plant typically uses diesel trucks.

[0119] The carbon emissions from transporting recyclable wood molds from the demolition site to the recycling plant are calculated using the following formula:

[0120]

[0121] In the formula, This represents the carbon emissions during the transportation and processing of recyclable wood formwork, where D represents the average transportation distance. This indicates the energy consumption per unit mass of diesel truck during transportation. Diesel carbon emission factor (unit: / L).

[0122] Second, calculate the carbon emissions of the recycling process, including the carbon emissions of transporting the treated wood from the recycling plant to the production plant, the carbon emissions of supplementary materials, and the carbon emissions of the treated wood production process.

[0123] After being transported to the recycling plant, recyclable wood formwork undergoes crushing, drying, and chemical treatment. This process can be labeled as Energy-Saving Process B. The carbon emissions generated during the recycling plant's processing are expressed by the following formula:

[0124]

[0125] In the formula, This indicates the carbon emissions throughout the entire processing phase of the recycling plant. This indicates the carbon emissions from crushing wooden formwork into qualified waste. This indicates the carbon emissions from drying wood templates into qualified waste material. This indicates the carbon emissions from transporting recyclable wooden formwork to a recycling plant for chemical treatment.

[0126] The carbon emission calculation formula for crushing wood formwork into qualified waste (particle size ≤ 5cm) is as follows:

[0127]

[0128] In the formula, This indicates the rated power of the crusher (unit: kW). This indicates the time (in hours) for crushing a unit mass of wooden formwork.

[0129] The carbon emission calculation formula for drying timber formwork into qualified waste is as follows:

[0130]

[0131] In the formula, Indicates the rated power of the drying equipment. This indicates the drying time per unit mass of wood chips. This represents the auxiliary heat source consumption during the drying process (unit: L / t, taking natural gas as an example), taken as 80-120 L / t. Natural gas carbon emission factor (unit: / L), take 0.0021 / L.

[0132] During the crushing, drying, and chemical treatment processes, the cellulose and hemicellulose in the wood may undergo slight decomposition, releasing small amounts of... Recycled wood formwork scraps need to undergo chemical treatment for preservation and insect control before processing. The preservatives and insect control agents used (such as urea-formaldehyde resin) will release substances during their production, use, and degradation. Especially for raw materials with a relatively low degree of decay, this process involves the consumption of chemical agents and the resulting carbon emissions. Therefore, the carbon emission calculation formula for transporting recyclable wood formwork to a recycling plant for chemical treatment is as follows:

[0133]

[0134] In the formula, Carbon emission factor (unit: ) for the production and use of preservatives / t), urea-formaldehyde resin agents are taken at 2.8-3.2. / t, environmentally friendly water-based chemicals are taken at 1.5-1.8 / t, This indicates the chemical consumption per unit mass of wood chips (unit: t / t). Referring to the "Classification and Requirements for the Use of Preservative-Preservative-Treated Timber" (GB / T 27651-2011), take 0.03-0.05 t / t. Indicates the carbon emission coefficient of trace decomposition of wood fibers during the treatment process (unit: / t), referring to research on carbon emissions from wood pyrolysis, take 0.08-0.12 / t.

[0135] The carbon emissions from transporting treated timber from the recycling plant to the production plant are calculated using the following formula:

[0136]

[0137] In the formula, This indicates the carbon emissions during the transportation of processed timber. This represents the amount of wood formwork consumed after crushing, and D represents the average transportation distance. This indicates the energy consumption per unit mass of diesel truck during transportation. This indicates the carbon emission factor of diesel fuel.

[0138] If the amount of recycled engineered wood products cannot meet production needs, supplementary materials, namely logs, must be added. The carbon emission calculation formula for supplementary materials is as follows:

[0139]

[0140]

[0141] In the formula, Indicates the carbon emissions of supplementary materials. This indicates the amount of raw timber scraps that need to be replenished. This indicates the carbon emission factor of producing log wood chips using traditional methods. This indicates the total demand for engineered wood products in secondary use scenarios. This indicates the amount of wood templates consumed after being broken up;

[0142] Timber dismantling in construction projects: According to the "Technical Guidelines for Resource Utilization of Construction Waste", among the dismantled wooden formwork, the proportion of severely decayed (losing mechanical properties or containing a large amount of mold) is about 10% to 30%, the proportion of slightly decayed (partially deteriorated but can be removed through processing) is about 15% to 25%, and the remaining 45% to 75% is the part that can be used directly or after simple treatment.

[0143] Criteria for judging wood decay: Referring to GB / T 13942.1-2009 Wood durability properties - Part 1: Laboratory test methods for natural decay resistance, when the density loss rate of decayed wood exceeds 20%, it is usually judged as unsuitable for use as raw material for structural or engineered wood products and must be removed as waste.

[0144] The carbon emissions from the processing of treated wood in the manufacturing plant, specifically the process of hot-pressing, gluing, cooling, trimming, and sanding treated wood chips to produce recycled engineered wood panels, can be categorized as an energy-saving C-process, as shown in the following formula:

[0145]

[0146] In the formula, This indicates that the carbon emissions from processing recycled engineered wood panels in factories using traditional processes are being addressed. This indicates the carbon emissions during the hot pressing process. This indicates the carbon emissions during the adhesive application process. This indicates carbon emissions during the cooling process. This indicates the carbon emissions from the trimming and sanding processes.

[0147] The carbon emissions from the hot pressing process are represented as follows:

[0148]

[0149]

[0150] In the formula, This indicates the total consumption of wood scraps and logs after the wood templates are crushed for the production of engineered wood products. This indicates the amount of raw timber scraps that need to be replenished. This indicates the amount of wood templates consumed after being broken up; This indicates the rated power of the multi-layer hot press. This indicates the time required for hot pressing a unit mass of recycled board. This represents the carbon emission factor for electricity.

[0151] The carbon emissions from the adhesive application process are represented as follows:

[0152]

[0153]

[0154]

[0155] In the formula, This indicates the quality of the adhesive used in the application process. Indicates the carbon emission factor of adhesives. This indicates the quality of the engineered wood product after hot pressing. This indicates the mass ratio of adhesive to the mass of the engineered wood product after hot pressing. This indicates the total mass loss rate from scrap to engineered wood products.

[0156] The carbon emissions from the cooling process are represented as follows:

[0157]

[0158] In the formula, Indicates the rated power of the cooling equipment. This indicates the time required to cool a unit mass of engineered wood panel after hot pressing. Indicates the carbon emission factor of electricity. This indicates the quality of the engineered wood panel after gluing.

[0159] The carbon emission calculation formula for the trimming and sanding process is as follows:

[0160]

[0161]

[0162] In the above formula, This indicates the rated power of the trimming machine. This indicates the time it takes for the engineered wood panel to cool after the trimmed unit mass is removed. This indicates the rated power of the sander. This indicates the time required for a unit mass of sanded engineered wood panel to cool. This indicates the quality of the engineered wood panel after cooling. This indicates the mass loss rate during the cooling process. According to the "Building Carbon Emission Calculation Standard" (GB / T51366-2019), the cooling loss rate during the building material processing is clearly defined, and the cooling loss rate is generally between 1% and 3%.

[0163] Compared to directly using logs to produce engineered wood products, based on the preliminary decomposition and accounting results, the comprehensive carbon emission factor of energy consumption is quantified and summarized. The comprehensive carbon emission factor of energy consumption for processing recycled wood templates into engineered wood products is shown in the following formula:

[0164]

[0165] In the formula, This refers to the comprehensive carbon emission factor of energy consumption during the production of recycled engineered wood panels using waste wooden formwork generated from the demolition of old buildings as part of the raw materials. The comprehensive carbon emission factor represents the energy consumption during the production of engineered wood products. This indicates the proportion of shredded wood template waste consumed during the production of engineered wood panels. This indicates the energy-saving index of shredded wood formwork waste, which is the energy-saving index of wood formwork waste recycling relative to traditional disposal.

[0166] The energy-saving index of wood formwork waste recycling compared to traditional disposal methods can be found in Tables 2 and 3. The energy-saving index of wood formwork waste is generally between 30% and 60%.

[0167] Table 2 Reference Table for Carbon Emission Factors of Recycled Wood Formwork Processing and Utilization of Recycled Wood-based Panels

[0168]

[0169] Table 3 Energy Consumption Index per Unit Product for Each Process in Wood-based Panel Production

[0170]

[0171] In this implementation, the energy consumption in the production of engineered wood products mainly comes from fossil fuel consumption (such as electricity and natural gas) and production process energy consumption (such as drying and hot pressing). The comprehensive carbon emission factor is essentially the sum of carbon emissions corresponding to various energy consumptions during the production of a unit mass of engineered wood products. Therefore, the expression for the comprehensive carbon emission factor of energy consumption in the production process of engineered wood products is as follows:

[0172]

[0173] In the formula, This represents the average electricity consumption for producing 1 ton of engineered wood products (unit: kWh / t). This represents the average natural gas consumption (unit: m³ / t) for producing 1 ton of general-purpose engineered wood panel. The figure represents the carbon emission factor of natural gas (unit: ). / m³).

[0174] Table 4 provides a reference for calculating the high and low limits of energy consumption and carbon emission factors in the production of wood-based panels.

[0175] Table 4. Calculation Table of High and Low Limits for Energy Consumption and Carbon Emission Factors in Wood-based Panel Production

[0176]

[0177] Third, calculate the carbon emissions of traditional process factories processing recycled wood-based panels, construct a carbon emission difference calculation model between traditional and recycled processes, and quantify the total carbon emission savings from using waste wood templates to replace virgin wood.

[0178] The carbon emissions from processing recycled wood-based panels using traditional methods are calculated, including emissions from three stages: traditional logging, traditional transportation, and traditional production. The formula is as follows:

[0179]

[0180] In the formula, This indicates the carbon emissions from the production of traditional virgin engineered wood panels in conventional factories. This indicates the carbon emissions from electricity consumed during the logging process in traditional methods. This indicates the carbon emissions from diesel fuel consumed during the transportation phase of traditional processes. This represents the total carbon emissions generated by energy consumption and chemical reactions in the traditional production process of engineered wood panels.

[0181] The carbon emissions from mechanical energy consumption during the logging, felling, pruning, and timber collection processes in forest land, and the carbon emissions from electricity consumption in the traditional logging process, are calculated using the following formula:

[0182]

[0183] In the formula, This indicates the total volume processed by traditional virgin timber factories. This indicates the carbon emission factor per unit of logging;

[0184] The carbon emissions from transporting logs from the logging site to the engineered wood product factory via diesel trucks in traditional processes are calculated using the following formula:

[0185]

[0186] In the formula, This indicates the average transportation distance from the logging site to the wood-based panel manufacturing plant. This indicates the unit mass transportation energy consumption of diesel trucks (the amount of diesel consumed to transport 1 ton of goods for 1 km). Indicates the carbon emission factor of diesel fuel;

[0187] The carbon emissions from traditional log processing into engineered wood products mainly come from two aspects: equipment electricity consumption and adhesive consumption. The formula for calculating the total carbon emissions from energy consumption and chemical reactions in traditional engineered wood product manufacturing processes is as follows:

[0188]

[0189] In the formula, This represents the total electricity required to produce 1 ton of engineered wood panels. Indicates the carbon emission factor of electricity. Indicates the carbon emission factor of adhesives (unit: / t), This indicates the mass ratio of adhesive to the mass of the engineered wood panel after hot pressing.

[0190] A carbon emission difference calculation model for traditional and recycled processes was constructed to quantify the total carbon emission savings from replacing virgin wood with waste wood templates.

[0191] The expression for constructing the carbon emission difference accounting model between traditional and regeneration processes is as follows:

[0192]

[0193] In the formula, This indicates the carbon emission reduction from using waste wood templates to produce recycled engineered wood panels. This indicates the carbon emissions from the traditional production of engineered wood panels. This indicates the carbon emissions of the recycling process that uses waste wood templates to regenerate engineered wood panels.

[0194] The specific calculation method, combining the above carbon emission calculation formulas, yields the following formula for calculating the carbon emissions of traditional processes for producing engineered wood panels:

[0195]

[0196] The carbon emission calculation formula for recycling engineered wood panels from waste wood templates is as follows:

[0197]

[0198] Therefore, the total carbon emission savings from replacing virgin timber with waste wood formwork can be expressed as follows:

[0199]

[0200] In the construction phase of secondary new buildings, recycled engineered wood panels made from recycled materials will be given priority. When the inventory of recycled engineered wood panels is insufficient to support the entire construction demand, conventional engineered wood panels will need to be purchased from the external market to fill the gap. For these purchased conventional engineered wood panels, the carbon emissions generated during their production process must be strictly measured in accordance with the accounting methods for the building material production stage as stipulated in the national standard GB / T 51366-2019 "Standard for Calculation of Carbon Emissions from Buildings".

[0201] If the production output of recycled engineered wood products exceeds the actual usage of this construction project, the surplus will be allocated to other construction or engineering projects. This effectively replaces the conventional engineered wood products that those projects would have originally consumed, thus offsetting the corresponding amount of carbon emissions from conventional engineered wood production. The calculation basis for the offset is consistent with the calculation rules for supplementary procurement, both using the same accounting model in the aforementioned national standards.

[0202] Specific example: A five-story library in a certain city was selected as the demolition project, with a building area of ​​15,378.5 square meters. The waste wood generated from the demolition was chosen as the recyclable material, processed into recycled artificial boards, and then used in the carbon emission accounting model of the present invention for calculation.

[0203] After calculation, it was found that:

[0204] Depend on The total mass of the discarded wooden formwork obtained from the demolition of the project is 522.869 tons; The total recyclable timber formwork obtained from the demolition of the project is 266.663 tons; The total weight of the non-recyclable wooden formwork is 256.206 tons; after dismantling, crushing, drying, and chemical treatment, it is recycled... The mass of wood template scrap obtained was 258.663t; from The carbon emissions generated during the recycling and reprocessing process are 273.1. Compared to the same amount of engineered wood produced using traditional methods The resulting carbon emissions are 301.9. Carbon emissions during the production phase were reduced by a total of 28.8%. .

[0205] The carbon emission accounting method for the recycling and reprocessing of waste wooden formwork into engineered wood products constructed in this invention can accurately calculate the carbon emissions of waste wooden formwork of different types and service stages throughout the entire process. It fills the gap in the current industry where there are no relevant accounting standards and the lack of research on carbon accounting for the life cycle recycling of wood materials. It reconstructs the circular development ideas of wood materials and provides a feasible quantitative tool for evaluating the carbon emission reduction benefits of specific projects. It has practical significance for promoting the low-carbon development of the construction industry and improving the recycling rate of waste wooden formwork resources. At the same time, it has both theoretical innovation value and industrial application value.

[0206] Although the steps in the above embodiments are described in the above order, those skilled in the art will understand that in order to achieve the effect of this embodiment, different steps do not need to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple variations are all within the protection scope of this invention.

[0207] Those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims of this invention, any one of the claimed embodiments can be used in any combination. It will be readily understood by those skilled in the art that the scope of protection of this invention is obviously not limited to these specific embodiments. Without departing from the principles of this invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from these changes or substitutions will all fall within the scope of protection of this invention.

Claims

1. A method for carbon emission accounting throughout the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels, characterized in that... Includes the following: The total mass of waste wood formwork and the mass of recyclable wood formwork are calculated based on the building area of ​​the demolition project. The carbon emissions during the demolition of recyclable wood formwork and the carbon emissions during the transportation of recyclable wood formwork from the demolition site to the recycling plant are also calculated. The carbon emissions from the recycling process are calculated, including the carbon emissions from transporting the treated wood from the recycling plant to the production plant, the carbon emissions from supplementary materials, and the carbon emissions from the production process of the treated wood. The carbon emissions from processing recycled engineered wood panels using traditional processes are calculated. A carbon emission difference calculation model between traditional and recycled processes is constructed to quantify the total carbon emission savings from replacing virgin wood with waste wood formwork.

2. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 1, characterized in that, The total mass of waste wood formwork and the mass of recyclable wood formwork are calculated based on the building area of ​​the demolition project. Considering natural wear and tear during the lifespan of the wooden formwork, the total mass of discarded wooden formwork and the mass of recyclable wooden formwork are calculated using the following formula: ； ； In the above formula, This indicates the total mass of the dismantled waste wooden formwork. The building area to be demolished. This refers to the initial amount of wooden formwork used per unit area. Waste rate of wooden formwork; This indicates the quality of recyclable waste wood formwork. Indicates the recyclable percentage of wooden formwork. This indicates the loss rate caused by tearing of wooden formwork and residual nails during the dismantling process; The calculation of carbon emissions during the dismantling of recyclable wood formwork is as follows: Carbon emissions are generated during the dismantling of recyclable wood formwork due to both mechanical crushing and cutting, and manual operation. ； In the formula, This indicates the total carbon emissions during the removal of recyclable wood formwork. This indicates carbon emissions during the use of machinery. This represents the carbon emissions from the labor metabolism of demolition workers. This indicates the total carbon emissions from processing non-recyclable wood formwork; The carbon emissions from the transportation of the recyclable wood molds from the demolition site to the recycling plant are calculated using the following formula: ； In the formula, This represents the carbon emissions during the transportation and processing of recyclable wood formwork, where D represents the average transportation distance. This indicates the energy consumption per unit mass of diesel truck during transportation. This indicates the carbon emission factor of diesel fuel.

3. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 2, is characterized in that, When calculating the carbon emissions during the dismantling of recyclable wood formwork, the carbon emissions generated by mechanical crushing and cutting during the dismantling process are calculated using the following formula: ； In the formula, Indicates the rated power of the electric machinery. Indicates the operating time of the electric machinery. Indicates the carbon emission factor of electricity. This indicates the fuel consumption of diesel machinery. Indicates the usage of different types of machinery; The carbon emissions from the labor metabolism of the demolition workers are calculated using the following expression: ; In the formula, Indicates the number of demolition workers. This indicates the average working time per person. This represents the average metabolic rate per person. Indicates the carbon emission factor of food; The total carbon emissions from the treatment of non-recyclable wood formwork are calculated using the following formula: ； In the formula, This indicates the carbon emissions during the processing of non-recyclable wood formwork. This indicates carbon emissions during the transportation of non-recyclable wooden formwork.

4. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 1, characterized in that, The carbon emissions from the recycling process at the plant are calculated as follows: Recyclable wooden formwork transported to the plant undergoes crushing, drying, and chemical treatment. The resulting carbon emissions are expressed using the following formula: ； In the formula, This indicates the carbon emissions throughout the entire processing phase of the recycling plant. This indicates the carbon emissions from crushing wooden formwork into qualified waste. This indicates the carbon emissions from drying wood templates into qualified waste material. This refers to the carbon emissions from transporting recyclable wooden formwork to a recycling plant for chemical treatment. The carbon emissions from transporting treated timber from the recycling plant to the production plant are calculated using the following formula. ； In the formula, This indicates the carbon emissions during the transportation of processed timber. This represents the amount of wood formwork consumed after crushing, and D represents the average transportation distance. This indicates the energy consumption per unit mass of diesel truck during transportation. Indicates the carbon emission factor of diesel fuel; The carbon emissions from the processed wood production process are calculated using the following formula: ； In the formula, This indicates that the carbon emissions from processing recycled engineered wood panels in factories using traditional processes are being addressed. This indicates the carbon emissions during the hot pressing process. This indicates the carbon emissions during the adhesive application process. This indicates carbon emissions during the cooling process. This indicates the carbon emissions from the trimming and sanding processes.

5. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 4, characterized in that, The carbon emission calculation formula for crushing the wooden formwork into qualified waste is as follows: ； In the formula, This indicates the rated power of the crusher. This indicates the time required to crush a unit mass of wooden formwork. This indicates the quality of recyclable waste wood formwork. Indicates the carbon emission factor of electricity; The carbon emission calculation formula for drying the wooden formwork into qualified waste is as follows: ； In the formula, Indicates the rated power of the drying equipment. This indicates the drying time per unit mass of wood chips. This indicates the amount of auxiliary heat source consumed during the drying process. Indicates the carbon emission factor of natural gas; The carbon emission calculation formula for transporting the recyclable wood template to the recycling plant for chemical treatment is as follows: ； In the formula, This indicates the carbon emission factor from the production and use of preservatives. This indicates the amount of chemical reagents consumed per unit mass of wood chips. This indicates the carbon emission coefficient from the trace decomposition of wood fibers during the treatment process.

6. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 4, is characterized in that, The carbon emissions from the hot pressing process are expressed as follows: ； ； In the formula, This indicates the total consumption of wood scraps and logs after the wood templates are crushed for the production of engineered wood products. This indicates the amount of raw timber scraps that need to be replenished. This indicates the amount of wood templates consumed after being broken up; This indicates the rated power of the multi-layer hot press. This indicates the time required for hot pressing a unit mass of recycled board. Indicates the carbon emission factor of electricity; The carbon emissions from the sizing process are represented as follows: ； ； ； In the formula, This indicates the quality of the adhesive used in the application process. Indicates the carbon emission factor of adhesives. This indicates the quality of the engineered wood product after hot pressing. This indicates the mass ratio of adhesive to the mass of the engineered wood product after hot pressing. This indicates the total mass loss rate from scrap to engineered wood products; The carbon emissions from the cooling process are represented as follows: ； In the formula, Indicates the rated power of the cooling equipment. This indicates the time required to cool a unit mass of engineered wood panel after hot pressing. This indicates the quality of the engineered wood panel after gluing. The carbon emission calculation formula for the trimming and sanding process is as follows: ； ； In the above formula, This indicates the rated power of the trimming machine. This indicates the time it takes for the engineered wood panel to cool after the trimmed unit mass is removed. This indicates the rated power of the sander. This indicates the time required for a unit mass of sanded engineered wood panel to cool. This indicates the quality of the engineered wood panel after cooling. This indicates the mass loss rate during the cooling process.

7. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 1, characterized in that, The carbon emission accounting formula for the supplementary material is as follows: ； ； In the formula, Indicates the carbon emissions of supplementary materials. This indicates the amount of raw timber scraps that need to be replenished. This indicates the carbon emission factor of producing log wood chips using traditional methods. This indicates the total demand for engineered wood products in secondary use scenarios. This indicates the amount of wood templates consumed after being broken.

8. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 1, characterized in that, The calculation of carbon emissions from the processing of recycled wood-based panels in traditional process factories includes carbon emissions from three stages: traditional logging, traditional transportation, and traditional production. The calculation formula is as follows: ； In the formula, This indicates the carbon emissions from the production of traditional virgin engineered wood panels in conventional factories. This indicates the carbon emissions from electricity consumed during the logging process in traditional methods. This indicates the carbon emissions from diesel fuel consumed during the transportation phase of traditional processes. This represents the total carbon emissions generated by energy consumption and chemical reactions in the traditional production process of engineered wood panels.

9. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 8, characterized in that, The formula for calculating the carbon emissions from electricity consumption during the logging process in the traditional method is as follows: ； In the formula, This indicates the total volume processed by traditional virgin timber factories. This indicates the carbon emission factor per unit of logging; The formula for calculating the carbon emissions of diesel fuel consumed during the transportation stage in the traditional process is as follows: ； In the formula, This indicates the average transportation distance from the logging site to the wood-based panel manufacturing plant. This indicates the energy consumption per unit mass of diesel truck during transportation. Indicates the carbon emission factor of diesel fuel; The formula for calculating the total carbon emissions from energy consumption and chemical reactions in the traditional process of producing engineered wood panels is as follows: ； In the formula, This represents the total electricity required to produce engineered wood panels. Indicates the carbon emission factor of electricity. Indicates the carbon emission factor of adhesives. This indicates the mass ratio of adhesive to the mass of the engineered wood panel after hot pressing.

10. The carbon emission accounting method for the entire process of recycling and remanufacturing waste wooden formwork into engineered wood panels according to claim 1, characterized in that, The expression for the carbon emission difference calculation model for the traditional process and the regeneration process is as follows: ； In the formula, This indicates the carbon emission reduction from using waste wood templates to produce recycled engineered wood panels. This indicates the carbon emissions from the traditional production of engineered wood panels. This indicates the carbon emissions of the recycling process that uses waste wood templates to regenerate engineered wood panels.

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