A method for establishing an ethylene plant product processing expense system

Abstract

The application relates to a method for establishing an ethylene device product processing cost system, and belongs to the technical field of ethylene production. The method comprises the following steps: step 1, determining the circulating processing cost of intermediate products; step 2, determining the single-pass processing cost of the ethylene device; and step 3, adding the circulating processing cost of the intermediate products determined in step 1 and the single-pass processing cost of the ethylene device calculated in step 2 to determine the processing cost of the ethylene device products. In the method for establishing the ethylene device product processing cost system, the influence of intermediate products generated in the cracking process on raw materials is considered, and the difference between the processing costs of different types of cracking furnaces in cracking different types of raw materials is considered, so that the disadvantages of the prior art in calculating the product structure model of a specific cracking furnace and specific raw materials by using commercial software are overcome.

Description

Technical Field

[0001] A method for establishing a product processing cost system for an ethylene plant belongs to the field of ethylene production technology. Background Technology

[0002] Ethylene plants are the leading petrochemical production facilities. Their production processes are relatively complex, involving both physical and chemical reactions, and ranging from high temperatures (1300℃) to low temperatures (-170℃). The main processes include cracking, quenching, compression, and separation, all of which are typical chemical unit processes.

[0003] Accurate calculation of ethylene plant processing costs is a crucial factor affecting the final profitability of ethylene production. The main factors influencing ethylene plant processing costs are the feedstocks, as the price differences between feedstocks are significant due to variations in supplier supply models. Another important factor is the varying degrees of cracking depth among different feedstocks. Different ethylene feedstocks will crack into several intermediate products after entering the cracking furnace. These intermediate products will be returned to the cracking furnace for multiple cycles of cracking until they are completely transformed into the target product. Each cycle of cracking increases processing costs.

[0004] Variable processing costs for ethylene plants mainly consist of three parts: fuel, power, and auxiliary materials. In actual cost calculations, the total data consumed by the ethylene plant in the current period is used as the basis, and it is impossible to break them down by raw material type. To ensure the scientific reliability of the calculation results, reasonably determining the processing costs of each raw material is crucial for data accuracy.

[0005] Existing technologies merely address the issue of cracking depth in pyrolysis furnaces. Commercial software is used to calculate single-pass product structure models for specific pyrolysis furnaces and raw materials. However, these technologies cannot solve the problem of increased costs due to large quantities of recycled ethane and propane, which leads to inflated marginal contributions of raw materials. Therefore, it is difficult to calculate the processing costs of each raw material. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a method for establishing an ethylene plant product processing cost system that considers the impact of intermediate products generated during the cracking process being returned to the cracking furnace for further cracking, and also considers the differences in processing costs when cracking different types of raw materials in different types of cracking furnaces. Compared with the shortcomings of the prior art in calculating the single-pass product structure model of a specific cracking furnace and a specific raw material using commercial software, this method corrects the consumption data of different cracking furnace types and cracking raw materials to obtain processing costs that conform to actual operating results.

[0007] The technical solution adopted by this invention to solve its technical problem is: a method for establishing a product processing cost system for an ethylene plant, characterized by the following steps: Step 1: Determine the cost of cyclical processing of intermediate products; Step 2: Determine the one-way processing cost of the ethylene unit; Step 3: Add the cyclic processing cost of the intermediate product calculated in Step 1 to the single-trip processing cost of the ethylene unit calculated in Step 2 to determine the processing cost of the ethylene unit product.

[0008] Preferably, step 1 includes the following steps: Step 1-1: Determine the total circulation volume of intermediate products; Steps 1-2: Based on the kinetic energy consumption per ton of feedstock in the ethylene unit, calculate the weight of standard oil consumed per ton of feedstock, and then calculate the processing cost per ton of feedstock in the ethylene unit based on the price of standard oil per ton. Steps 1-3: Based on the proportion of the total recycling volume of intermediate products to the total raw material input obtained in Step 1-1, determine the recycling cost of intermediate products under the current operating conditions.

[0009] Preferably, step 2 includes the following steps: Step 2-1: First, calculate the total cost of processing raw materials in the current period based on the current ethylene unit cost table. Then, deduct the cost of auxiliary materials from the total cost of processing raw materials in the current period, and then subtract the average value of the cycle processing cost of each cracking furnace. Finally, obtain the overall single-pass cracking process processing cost of the unit. Step 2-2: Using the normalization method, calculate the proportion of fuel gas consumption per ton of raw material in each type of cracking furnace to the total average fuel gas consumption per ton of raw material. Step 2-3: The proportion of fuel gas consumption per ton of raw material in each furnace type simulation calculation obtained in Step 2-2 to the total average fuel gas consumption per ton of raw material is used as a weight to calculate the single-pass processing cost of the unit, thereby obtaining the single-pass processing cost of each raw material for each cracking furnace.

[0010] Preferably, the intermediate products include ethane, propane, acetylene, and methylacetylene.

[0011] Preferably, in step 1-1, the number of cycles required for each intermediate product to be consumed is determined, the weight of each pyrolysis cycle is obtained based on the conversion rate of each intermediate product, the weights of each intermediate product in each pyrolysis cycle are added together to obtain the total cycle amount of the intermediate product, and the total cycle amount of all intermediate products is added together to obtain the total cycle amount of the intermediate product.

[0012] Compared with the prior art, the beneficial effects of this invention are: In the method for establishing the product processing cost system of this ethylene plant, the impact of intermediate products generated during the cracking process being returned to the cracking furnace for further cracking on the feedstock is considered. At the same time, the differences in processing costs between different types of cracking furnaces when cracking different types of feedstocks are also considered. Compared with the shortcomings of existing technologies that use commercial software to calculate product structure models for specific cracking furnaces and specific feedstocks, the processing costs are corrected for different types of cracking furnaces and feedstock consumption data to obtain processing costs that conform to actual operating results.

[0013] In the method for establishing the product processing cost system of this ethylene plant, based on the cost table of the ethylene plant, the current fuel, power and auxiliary material consumption is used as the data basis. By calculating the weight coefficient, the data on the consumption of different cracking furnace types and cracking feedstocks are corrected to obtain the processing cost that conforms to the actual operating results.

[0014] The method for establishing the product processing cost system of this ethylene plant solves the problem of the increased cost of circulating cracking of light feedstocks due to the large amount of circulating ethane and propane, which leads to an inflated marginal contribution per ton of feedstock.

[0015] The method for establishing the product processing cost system of this ethylene plant solves the problem that financial data cannot reflect the calculation of variable costs for different raw materials, avoids the solidification of costs, enables the data representation of the processing costs of different raw materials, and reasonably calculates the marginal contribution of different raw materials, making the calculation results more realistic and reliable. Attached Figure Description

[0016] Figure 1 A flowchart illustrating the method for establishing a product processing cost system for an ethylene plant.

[0017] Figure 2 A flowchart illustrating the calculation of intermediate product recycling costs for establishing a product processing cost system for an ethylene plant.

[0018] Figure 3 A flowchart illustrating the calculation of single-trip processing costs for establishing a product processing cost system for an ethylene plant. Detailed Implementation

[0019] Figures 1-3 This is the preferred embodiment of the present invention, which is described below in conjunction with the accompanying drawings. Figures 1-3 The present invention will be further described below.

[0020] like Figure 1 As shown, a method for establishing a product processing cost system for an ethylene plant includes the following steps: Step 1: Determine the cost of cyclical processing of intermediate products; During the production process of an ethylene plant, after the raw materials enter the plant and undergo a complete cracking process, in addition to producing the main products such as ethylene and propylene, various intermediate products are also generated during the cracking process. These intermediate products include ethane, propane, acetylene, and methylacetylene. Ethane, propane, acetylene, and methylacetylene are not discharged from the ethylene plant but are returned to the cracking furnace inside the plant for further reaction. As the intermediate products are continuously returned to the cracking furnace, they are consumed according to a certain conversion rate until their weight drops to a negligible value (such as 1 kg), at which point it is considered that the intermediate products have been completely consumed.

[0021] As intermediate products are continuously returned to the pyrolysis furnace, they mix with newly added raw materials and enter the furnace together. Therefore, the actual energy consumption in the pyrolysis furnace is greater than the energy required by the raw materials themselves. Since the intermediate products produced after one pyrolysis of a unit weight of raw materials need to undergo multiple pyrolysis processes before they are considered to be completely consumed, each time the intermediate products are returned for pyrolysis, fuel consumption increases. Therefore, it is necessary to determine the processing costs incurred by continuously circulating intermediate products until they are completely consumed.

[0022] like Figure 2 As shown. This step includes the following sub-steps: Step 1-1: Determine the total circulation volume of intermediate products; First, based on the conversion rates of ethane and propane, iterative calculations were performed on ethane, propane, acetylene, and methylacetylene using existing mechanistic models, including but not limited to: Pertosim developed by KBC, Spyro software from Technip, and Coilsim software from East China University of Science and Technology.

[0023] Steps 1-2: Calculate the processing cost per ton of raw material for the cracking furnace; Based on the kinetic energy consumption per ton of feedstock in an ethylene plant, the weight of standard oil consumed per ton of feedstock is calculated. Then, based on the price of standard oil per ton, the processing cost per ton of feedstock in the ethylene plant is calculated.

[0024] Steps 1-3: Determine the cost of recycling intermediate products; Based on the proportion of the total recycling volume of intermediate products to the total raw material input obtained in step 1-1, determine the recycling cost of intermediate products under the current operating conditions.

[0025] Step 2: Determine the one-way processing cost of the ethylene unit; The single-pass processing cost of an ethylene plant refers only to the cost incurred after the feedstock enters the ethylene plant and completes one cracking cycle, such as... Figure 3 As shown, this step includes the following sub-steps: Step 2-1 yields the overall single-pass cracking process cost of the ethylene processing unit; First, based on the current ethylene unit cost table, calculate the total processing cost per ton of raw material for the current period. The processing cost of the ethylene unit mainly includes fuel, power, and auxiliary materials. Among them, auxiliary materials are relatively fixed data, so they are eliminated as a factor. At the same time, the average value of the cycle processing cost of each cracking furnace is also eliminated, and finally the overall single-pass cracking process processing cost of the unit is obtained.

[0026] Step 2-2: Determine the energy consumption ratio of each type of pyrolysis furnace; Since different types of pyrolysis furnaces have different actual parameters, the processing cost of processing the same type and weight of raw materials in different types of pyrolysis furnaces is different. In this step, the normalization method is used to calculate the proportion of fuel gas consumption per ton of raw material in each type of pyrolysis furnace to the total average fuel gas consumption per ton of raw material.

[0027] Steps 2-3: Determine the single-pass processing cost for each raw material in each cracking furnace; The proportion of fuel gas consumption per ton of raw material in each furnace type simulation calculation obtained in step 2-2 to the total average fuel gas consumption per ton of raw material is used as a weight to calculate the single-pass processing cost of the unit, thereby obtaining the single-pass processing cost of each raw material in each cracking furnace.

[0028] Step 3: Determine the processing costs of the ethylene unit's products; The processing cost of the ethylene unit's products can be determined by adding the cyclic processing cost of the intermediate product calculated in step 1 and the single-trip processing cost of the ethylene unit calculated in step 2.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for establishing a product processing cost system for an ethylene plant, characterized in that: Includes the following steps: Step 1: Determine the cost of cyclical processing of intermediate products; Step 2: Determine the one-way processing cost of the ethylene unit; Step 3: Add the cyclic processing cost of the intermediate product calculated in Step 1 and the one-way processing cost of the ethylene unit calculated in Step 2 to determine the processing cost of the ethylene unit product. Step 1 includes the following steps: Step 1-1: Determine the total circulation volume of intermediate products; Steps 1-2: Based on the kinetic energy consumption per ton of feedstock in the ethylene unit, calculate the weight of standard oil consumed per ton of feedstock, and then calculate the processing cost per ton of feedstock in the ethylene unit based on the price of standard oil per ton. Steps 1-3: Based on the proportion of the total recycling volume of intermediate products to the total raw material input obtained in Step 1-1, determine the recycling cost of intermediate products under the current operating conditions. Step 2 includes the following steps: Step 2-1: First, calculate the total cost of processing raw materials in the current period based on the current ethylene unit cost table. Then, deduct the cost of auxiliary materials from the total cost of processing raw materials in the current period, and then subtract the average value of the cycle processing cost of each cracking furnace. Finally, obtain the overall single-pass cracking process processing cost of the unit. Step 2-2: Using the normalization method, calculate the proportion of fuel gas consumption per ton of raw material in each type of cracking furnace to the total average fuel gas consumption per ton of raw material. Step 2-3: The proportion of fuel gas consumption per ton of raw material in each furnace type simulation calculation obtained in Step 2-2 to the total average fuel gas consumption per ton of raw material is used as a weight to perform a weighted calculation of the single-pass processing cost of the unit, thereby obtaining the single-pass processing cost of each raw material in each cracking furnace. In step 1-1, the number of cycles required for each intermediate product to be consumed is determined. The weight of each pyrolysis cycle is obtained based on the conversion rate of each intermediate product. The weights of each intermediate product in each pyrolysis cycle are added together to obtain the total cycle amount of the intermediate product. The total cycle amount of all intermediate products is added together to obtain the total cycle amount of the intermediate products.

2. The method for establishing the product processing cost system of an ethylene plant according to claim 1, characterized in that: The intermediate products include ethane, propane, acetylene, and methylacetylene.

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