A method for environmental impact assessment of casting process based on example model

Abstract

The present invention belongs to the field of computer-aided design and manufacturing, and specifically relates to a method for environmental impact assessment of a casting process based on an example model, comprising: (1) selecting a casting process to be assessed and obtaining relevant information; (2) binding a structured digital model with a scene data model to generate an example model; (3) obtaining data of the casting process and generating an assessment example; (4) performing a list analysis on the process example to obtain list data; (5) performing an environmental impact assessment based on the list data. The method for environmental impact assessment of a casting process based on an example model provided by the present invention can effectively identify key links of energy conservation and emission reduction in the casting process.

Description

Technical Field

[0001] The invention belongs to the field of computer-aided design and manufacturing, and in particular relates to a casting process environmental impact assessment method based on an example model. Background Art

[0002] Casting technology is the basic technology of modern machinery manufacturing industry and one of the main methods to obtain blanks and parts of mechanical products. The foundry industry is an important industry of the national economy. While creating huge economic wealth, it also consumes a lot of manufacturing resources and has a serious impact on the environment. Therefore, implementing green manufacturing projects and improving green processes have become key strategies for the sustainable development of the foundry industry. An important prerequisite for improving green processes and promoting the implementation of green manufacturing projects is to achieve environmental impact assessment of the process.

[0003] Existing process environmental impact assessment usually regards the process as a whole and conducts evaluation based on averaged and combined data. Although this can effectively support environmental impact assessment and obtain quantitative evaluation results, it is difficult to identify the key links of energy conservation and emission reduction in the process based on such combined data. Summary of the invention

[0004] In view of this, the purpose of the present invention is to propose a casting process environmental impact assessment method based on an instance model, which can adapt to the dynamic changes of the process, obtain the environmental impact assessment results of the process, and provide method support for identifying the key links of energy conservation and emission reduction in the casting process.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A method for environmental impact assessment of a casting process based on an example model, the method specifically comprises:

[0007] Step 1: Select the casting process to be evaluated and obtain its process flow information and process element attribute information; where:

[0008] 1-1: The process flow information includes a process flow chart drawn in a two-dimensional coordinate plane and description information of the process flow chart;

[0009] 1-2: The elements in the process element attribute information refer to the constituent elements of the process, including the basic description of the process scenario, process objects, equipment, energy, key process parameters, auxiliary materials, environmental loads, and output components. The element attribute information refers to the values ​​of these element attributes.

[0010] Step 2: Input the process flow information into the structured digital model, input the process element attribute information into the process scenario data model, and bind the structured digital model with the scenario data model to generate a casting process instance model; wherein:

[0011] 2-1: The structured digital model of the casting process is represented as:

[0012] Model={Containers,C,Attribute prosess}

[0013] In the formula, Model represents the structured digital model of the casting process, Containers represents the link container set, C represents the adjacency matrix, Attribute prosess represents the set of characteristic indicators; their values ​​are obtained in step (1);

[0014] 2-2: The scene data model of the casting process is expressed as:

[0015] scene={sceneDescription, object, device, energy, parameters, auxMaterials, envLoad, outputPart}

[0016] In the formula, scene represents the process scene, sceneDescription represents the basic description of the process scene, object represents the process object, device represents the equipment, energy represents the energy, parameters represents the key process parameters, auxMaterials represents the auxiliary materials, i.e. the auxiliary materials that play the role of catalyst and protection in the casting process, envLoad represents the environmental load, i.e. the collection of environmental impact and load materials such as waste gas, waste liquid and waste water generated in the process, and outputPart represents the output component; their entity data are obtained in step (1);

[0017] 2-3: The example model of the casting process can be expressed as:

[0018] InstanceModel={ProcessId, ProcessTitle, Model, {Scence n},[Bind 1 , Bind 2 , ..., Bind n ]}Bind i = <P(x,y),Scence n >

[0019] In the formula, ProcessId is the primary key used to represent the uniqueness of the process and is the root node of the instance model. ProcessTitle is the name of the specific process. Model is the structured digital model of the process. n Bind represents the scene data model of the process i It represents the link container P(x, y) in the structured digital model and its corresponding nth scene data model Scence n At the same time, the process data of the link container will be standardized and described by the process scenario data model bound to it.

[0020] Step 3: Obtain casting process data and input it into the process instance model to generate a casting process evaluation instance;

[0021] Step 4: Build the physical table of the data entity in step 3, convert the attributes in the data entity into columns, and define the data structure of the columns, where:

[0022] Perform inventory analysis on the process instance to obtain inventory data; among which:

[0023] The casting process instance contains one or more process scenario instances, and its inventory data can be expressed as:

[0024] ProcessList = {SceneList i}; i ≥ 1

[0025] In the formula, ProcessList represents the casting process list data, SceneList i Indicates the process scenario list data. Further, the process scenario list data is divided into input data and output data, which are expressed as:

[0026] SceneList i ={SenceId,InputList,OutputList}

[0027] In the formula, SenceId represents the primary key of the process scenario, which identifies the uniqueness of the process scenario. InputList represents the input data list under the process scenario, and OutputList represents the output data list under the process scenario. The logical expression of the specific input and output data of the process scenario is defined in five-tuples, which is expressed as follows:

[0028] SceneData i ={SenceId, SubstanceType i , AttributeNamei ,Value i , Unit i}; i ≥ 1

[0029] In the formula, SceneData i Represents the input and output data of the process scene, SubstanceType i Indicates the material type, AttributeNamei indicates the input and output attribute name, Value i Indicates input and output data values, Unit i Indicates the data unit.

[0030] Step 5: Based on the casting process inventory data obtained in step 4, conduct an environmental impact assessment on the selected casting process. It mainly includes four technical steps: classification, characterization, standardization and weighting. Classification is to classify the inventory analysis results into corresponding environmental impact types according to the property type; characterization is to convert the environmental load factors of the same impact type in the inventory results into the same unit through the same measurement benchmark, and merge the converted inventory results, and then calculate the environmental impact potential of the environmental impact type. The specific calculation method is as follows:

[0031] EI i =∑(Emission j ×C ij )

[0032] Where, EI i It represents the environmental impact potential value after characterization of environmental impact type i, Emission j represents the inventory result of environmental load factor j, C ij It represents the equivalent factor of environmental load factor j to environmental impact type i;

[0033] Standardization is the process of standardizing the characterization results by introducing a benchmark value. The purpose is to eliminate the differences in magnitude and dimension of various environmental impact results, achieve dimensionlessness, and make environmental impact types of different dimensions comparable. The specific calculation method of standardization is as follows:

[0034]

[0035] Where N i is the standardized result of environmental impact type i, S i represents the standardized benchmark value of environmental impact type i;

[0036] Weighting is the process of assigning corresponding weight factors according to the contribution values ​​of different environmental impact types, and weighting and summing the potential values ​​of different environmental impact types to obtain a comprehensive environmental impact assessment result. The specific calculation method of weighting is as follows:

[0037] En LCA =∑(N i ×W i )

[0038] In the formula, En LCA It represents the total environmental impact result, i.e. the life cycle environmental impact result, W i It represents the weight factor of environmental impact type i. The size of the weight factor determines the importance of the environmental impact type.

[0039] Through the above steps, the quantitative results of the environmental impact of the casting process are finally obtained, and the pollution problems and distribution caused by the casting process can be understood.

[0040] The beneficial effects of the present invention are:

[0041] According to the casting process environmental impact assessment method based on the example model proposed in the present invention, the specific process links and the process scenario data model are flexibly bound to facilitate expansion, reuse and maintenance. It is convenient to build a process information organization framework, and to quantify environmental emissions, understand the pollution problems and distribution generated in the casting process, and analyze the key emission stages and key environmental impact factors of the casting process, and provide method support for making suggestions for reducing emissions in the casting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0043] Figure 1 A flowchart of a casting process environmental impact assessment method based on an example model according to the present invention;

[0044] Figure 2 This is the process flow chart of 3.5 ton transport machine V normal casting;

[0045] Figure 3 This is the IPO model diagram of the 3.5-ton transporter;

[0046] Figure 4 The generation mechanism of the example model for the casting process;

[0047] Figure 5 It is the data model of smelting process scenario. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings:

[0049] Step 1: Take the V-normal casting process of a 3.5-ton transport machine of a foundry enterprise as an example to obtain its process flow information and process element attribute information; among which:

[0050] 1-1: The process flow chart is a two-dimensional plane coordinate diagram, such as Figure 2 As shown;

[0051] 1-2: The dimensions of the machine are 1150×950×850mm. The main equipment is a medium frequency electric furnace of 12.5×4 meters, a crane (16 tons), a V-molding machine, a lifting equipment (unpacking), a machine grinding equipment, a hand-held grinder and a high-pressure spraying equipment, etc. The other process element attribute information and related input and output IPO models are as follows Figure 3 shown.

[0052] Step 2: Input the process flow information into the structured digital model, input the process element attribute information into the process scenario data model, and bind the structured digital model with the scenario data model to generate a casting process instance model; its generation mechanism is as follows: Figure 4 As shown. Among them:

[0053] 2-1: The process of creating the structural digital model of the 3.5-ton transport machine V-normal casting is as follows:

[0054] Figure 2 In the two-dimensional coordinate plane shown, the horizontal axis represents the order of serial processes, and the vertical axis represents the parallel relationship between parallel processes; each process is marked on the two-dimensional coordinate plane according to the relationship between the processes; a link container is created for the coordinate point corresponding to each process, for example, the coordinates of the smelting process in the two-dimensional plane coordinate diagram of the casting process are: (2,2). The relationship between all link containers can be represented by an adjacency matrix C. The 11 numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are used to represent the 11 processes. These 11 numbers are used to represent the 11 processes or materials of molding materials, sand treatment, molding core making, pouring, sand dropping, cleaning, post-processing, castings, metal furnace materials, smelting, and pre-furnace treatment. These 11 numbers represent the 11 processes or materials, which constitute an unweighted directed graph. The corresponding adjacency matrix is ​​the adjacency matrix C of the 3.5-ton transport machine V normal casting process, which can be expressed as:

[0055]

[0056] According to the specific process represented by the link container, add the process input and output elements to the link container, where the input and output elements include process objects, auxiliary materials, equipment, energy, environmental load, output components and key process parameters. All link containers of the process are represented as link container sets. The link container set of the 3.5-ton V-normal casting process is represented as: Containers = {molding materials, sand treatment, molding core making, pouring, sand dropping, cleaning, post-processing, castings, metal furnace materials, smelting, furnace pre-processing}.

[0057] 2-2: The process scenario data model of 3.5-ton transport machine V-normal casting is created as follows:

[0058] Taking the melting process of 3.5-ton V-normal casting as an example, a process scenario data model is constructed. The components of the melting process scenario include the basic description of the process scenario, process objects, equipment, energy, key process parameters, auxiliary materials, environmental loads, and output components. Figure 5 shown.

[0059] 2-3: The example model of the 3.5-ton V-normal casting process can be expressed as:

[0060] InstanceModel = {1, Cast iron_Cast steel_Nonferrous metals_Dry sand casting (V method),

[0061] Model,{Scence n},[Bind 1 ,Bind 2 ,…Bind n ]}

[0062] Taking the smelting process scenario as an example, its binding relationship can be expressed as

[0063] Bind = {Bind i <P(2,2),S 熔炼 >}

[0064] Step 3: Obtain casting process data and input it into the process instance model to generate a casting process evaluation instance.

[0065] Step 4: Perform inventory analysis on the process instance to obtain inventory data: Based on the constructed process instance, perform inventory data analysis on the process to determine and quantify input and output data such as raw material and energy input, gas emissions, water pollution, solid waste, etc. The inventory data in this embodiment is shown in Table 1.

[0066] Table 1 List of data for the V-normal casting process of a 3.5-ton transport machine

[0067]

[0068] Step 5: Based on the casting process list data obtained in step 4, conduct an environmental impact assessment on the selected casting process.

[0069] The specific evaluation process is:

[0070] ①Classification

[0071] According to the actual production situation of the 3.5-ton V-normal casting process, 8 types of life cycle assessment indicators suitable for environmental impact assessment are established, as shown in Table 2. The impact types of the casting process life cycle assessment are: global warming potential, human toxicity potential, photochemical ozone formation potential, freshwater ecotoxicity potential, marine water ecotoxicity potential, terrestrial ecotoxicity potential, acidification potential, eutrophication potential, etc. The inventory analysis results are divided into the selected impact types to more clearly show the environmental problems related to the results.

[0072] Table 2 Classification of environmental impact types

[0073]

[0074] ② Characterization

[0075] Different substances may have the same impact on the environment, but the degree of their impact varies. Moreover, the proportion of each substance is very different. Some substances exist in extremely small amounts, but their impact on the environment is huge, while some substances exist in very large amounts, and their impact on the environment is negligible. This requires the potential impact of different substances in the inventory results on the same type of impact to be converted, that is, characterized. According to Table 1, the life cycle environmental impact emissions of each ton of 3.5-ton transport machine castings are calculated, and the environmental impact assessment characterization results of the 3.5-ton transport machine V-normal casting process are shown in Table 3.

[0076] Table 3 Results of life cycle environmental impact emission characterization

[0077]

[0078] ③ Standardization

[0079] After selecting the normalized reference value, the standardized results are shown in Table 4 below.

[0080] ④Weighting

[0081] After selecting the comprehensive weighted value, the weighted results are shown in Table 5 below.

[0082] From the evaluation results, it can be seen that the main contribution of the 3.5-ton V-normal casting process is the acidification impact potential, and the environmental impact value of the smelting process is the largest. This is because the entire process, especially the smelting process, consumes the most electricity. Therefore, optimizing the power structure and utilizing more renewable energy can effectively reduce the impact of the life cycle on the environment.

[0083] Table 4 Standardized results of life cycle environmental impact

[0084]

[0085] Table 5 Weighted results of life cycle environmental impact

[0086]

[0087] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for environmental impact assessment of a casting process based on an example model, characterized in that The steps include: Step 1: Select the casting process to be evaluated and obtain its process flow information and process element attribute information; Step 1 includes steps 1-1 and 1-2; 1-1: The process flow information includes a process flow chart drawn in a two-dimensional coordinate plane and description information of the process flow chart; 1-2: The elements in the process element attribute information refer to the constituent elements of the process, including the basic description of the process scenario, process objects, equipment, energy, key process parameters, auxiliary materials, environmental loads and output components, and the element attribute information refers to the values ​​of these element attributes; Step 2: inputting the process flow information into the structured digital model, inputting the process element attribute information into the process scenario data model, and binding the structured digital model with the scenario data model to generate a casting process instance model; Step 2 includes steps 2-1, 2-2 and 2-3; 2-1: The structured digital model of the casting process is represented as: Model={Containers,C,Attribute prosess } In the formula, Model represents the structured digital model of the casting process, Containers represents the link container set, C represents the adjacency matrix, Attribute prosess represents a set of characteristic indicators; the values ​​of the above parameters are obtained in step 1; 2-2: The scene data model of the casting process is expressed as: scene={sceneDescription,object,device,energy,parameters,auxMaterials,envLoad,outputPart} In the formula, scene represents the process scene, sceneDescription represents the basic description of the process scene, object represents the process object, device represents the device, energy represents the energy, parameters represents the key process parameters, auxMaterials represents the auxiliary materials, envLoad represents the environmental load, and outputPart represents the output part; the values ​​of the above parameters are obtained in step 1; 2-3: The example model of the casting process is expressed as: InstanceModel={ProcessId,ProcessTitle,Model,{Scence n },[Bind1,Bind2,…,Bind n ]} Bind i =<P(x,y),Scence n > In the formula, ProcessId is the primary key used to represent the uniqueness of the process and is the root node of the instance model. ProcessTitle is the name of the specific process. Model is the structured digital model of the process. n Bind represents the scene data model of the process i It represents the link container P(x,y) in the structured digital model and its corresponding nth scene data model Scence n At the same time, the process data of the link container will be standardized and described by the process scenario data model bound to it; Step 3: Obtain casting process data and input it into the process instance model to generate a casting process evaluation instance; Step 4: Perform inventory analysis on the process instance to obtain inventory data; Step 5: Based on the casting process list data obtained in step 4, conduct an environmental impact assessment on the selected casting process.

2. The method for environmental impact assessment of a casting process based on an example model according to claim 1, characterized in that: The step 4 is characterized in that the casting process instance contains one or more process scenario instances, and the list data thereof is represented as follows: ProcessList={SceneList i };i≥1 In the formula, ProcessList represents the casting process list data, SceneList i Represents the process scenario list data; the process scenario list data is divided into input data and output data, expressed as: SceneList i ={SenceId,InputList,OutputList} In the formula, SenceId represents the primary key of the process scenario, which identifies the uniqueness of the process scenario. InputList represents the input data list under the process scenario, and OutputList represents the output data list under the process scenario. The logical expression of the specific input and output data of the process scenario is defined in five-tuples, which is expressed as follows: SceneData i ={SenceId,SubstanceType i , AttributeName i ,Value i ,Unit i };i≥1 In the formula, SceneData i Represents the input and output data of the process scene, SubstanceType i Indicates the substance type, AttributeName i Indicates the input and output attribute name, Value i Indicates input and output data values, Unit i Indicates the data unit.

Images