Carbon emission evaluation function and calculation method of sand casting production system

1. Energy consumption of sand casting production system

The carbon emission of sand casting production system is related to energy consumption, so the energy consumption of each subsystem is analyzed and counted first.

(1) Energy consumption of process system

Energy consumption of sand casting process system refers to the total electric energy consumption of the equipment used in each process in the production process e1j, including the electric energy consumption of sand drying equipment, smelting equipment and sand removal and cleaning equipment.

Where ex represents the power consumption (KWH) of the x-th equipment during the production of a single casting.

(2) Energy consumption of auxiliary material module of upstream system

The auxiliary materials of casting process include mold (core) sand, limestone, coating, etc. The calculation of energy consumption of auxiliary materials takes core sand as an example. The energy consumption includes the total power consumption of various sand preparation equipment e12j1 required in the process of sand processing, and the energy consumption of J kinds of energy e22js consumed in the exploitation, transportation and processing of raw materials in sand molding.

Where: e12j1 refers to the total power consumption (KWH) of molding sand required by the sand preparation equipment to prepare a single casting; eg refers to the power consumption (KWH) of molding sand required by the g-th molding sand preparation equipment to prepare a single casting; α refers to the number of g-th equipment actually used on the molding sand preparation production line.

In the formula, e22j1 represents the energy consumption of the j-th energy source (kgce); ek2j represents the k-th component (kgce) of the energy consumption of the j-th energy source; EK represents the total energy consumption of the k-th molding sand raw material (kgce), which is composed of three parts: energy consumption ekex in the mining stage, energy consumption ektr in the transportation stage and energy consumption ekpr in the processing stage; FKJ represents the percentage of the j-th energy consumption in the total energy consumption of the k-th molding sand raw material.

Therefore, the energy consumption of molding sand production is

The total energy consumption of various auxiliary materials required for production of sand casting production system is expressed as

Where: e2j represents the total energy consumption (kgce) of various auxiliary materials required for the production of sand casting production system; e2js represents the total energy consumption (kgce) of the s auxiliary materials required for the production of sand casting production system.

(3) Energy consumption of raw material system

The energy consumption of raw material system includes the energy consumption of the burden of blast furnace ironmaking, i.e. sintering iron ore, coke and limestone in each stage of mining, transportation and processing. The data comes from simapro 7.1 database and field statistics (calculation as formula (3)), as well as the power consumption of the equipment required for blast furnace ironmaking, calculation method as process system energy consumption calculation.

In addition to pig iron, the main raw materials of sand casting production system also include other furnace materials in cupola, such as return iron, scrap steel, coke, limestone, etc. the energy consumption is included in the energy consumption of raw material system. Therefore, the CO2 generated by fuel combustion is included in the carbon emission generated by the energy consumption of raw material system, not included in the direct carbon emission on the site of sand casting production system. As the internal circulating material of the system, the carbon emission is not included according to the reference [8]. As the open-loop circulating material, the energy consumption of scrap steel shall be 50% of the environmental load caused by the recycling process by the system providing the recycled material and the system receiving the recycled material. According to the reference [8], the CO2 produced by the production of every kilogram of steel is 8.200kgco2e.

2. Carbon emission evaluation function of sand casting production system

According to the carbon emission characteristics of sand casting production system, various carbon emissions of production system are defined as follows: carbon emissions caused by various energy sources consumed in the process of mining, production, transportation and use are called energy carbon emissions; The carbon emission caused by various energy sources consumed in the production of various auxiliary materials by the auxiliary materials module in the upstream system during the process of mining, production, transportation and use, as well as the sum of the direct carbon emission of each process, is called process carbon emission; the carbon emission caused by various energy sources consumed in the production of raw materials in the raw materials system during the process of mining, production, transportation and use is called material carbon emission.

According to the above definition, the carbon emission estimation function of the casting production system is expressed as follows:

Where: CFP refers to the carbon emission of single casting produced by sand casting production system (kgco2e); CFPI refers to the three types of carbon emission of sand casting production system, cfp1 refers to the energy carbon emission, cfp2 refers to the process carbon emission, cfp3 refers to the material carbon emission (kgco2e); eij refers to the energy consumption (kgco2e) of production single casting included in the class I carbon emission; Efj refers to the carbon emission coefficient (kgco2e / kgce) of the j-th energy source, which is composed of carbon emissions in each stage of mining, production, transportation and use of the j-th energy source. The data is from literature [9], as shown in Table 1. CFPD refers to the direct carbon emissions (kgco2e) generated by the chemical change of slag making agent during the production of a single casting. B refers to the direct carbon emissions (kgco2e) generated by the chemical change of slag making agent, The mass of scrap steel added to the production of a single casting (kg); cfpst represents the carbon emission per kilogram of steel, and the data comes from literature [8], i.e. 8.200kgco2e/kg.

Table 1 carbon emission coefficient of various energy sources kgco2e / kgce

Table 1 carbon emission coefficient of various energy sources kgco2e / kgce

The function is suitable for carbon emission estimation of sand casting production system. The input of energy consumption and CO2 output in the system will be the input variables of the function, and the carbon emission of the whole system will be the output. Because the fuel used by each enterprise has different calorific value, the standard coal is used as the unified energy consumption measurement basis, so the function has certain universality.

3. Carbon emission calculation flow chart of sand casting production system

During the calculation, the system initialization shall be carried out first, and the relevant parameters of the enterprise shall be entered into the database, such as the performance parameters of various equipment, including the rated power and productivity of the equipment, which are used to calculate the energy consumption per unit casting; secondly, the quality per unit casting shall be determined as the basic calculation parameters, including the quality of the casting riser,

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