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Annual production of 150,000 tons of vinyl acetate project - summaryCatalogChapter I Project Description1Chapter II technological design22.1 Overview22.2 Source of raw materials22.3 Process flow32.3.1 Dry gas removal section32.3.2 Ethylene exquisite section52.3.3 Vinyl acetate synthesis section62.3.4 Vinyl acetate refining section82.4 Process innovation9Chapter III Equipment design10Chapter Energy saving and environmental protection114.1 Thermal integrated design114.2 Environmentally friendly design15Chapter V General plant and workshop layout17Chapter VI Economic Analysis19Chapter to sum up20Chapter I Project DescriptionChinas economic development has entered a new normal, and the development of manufacturing industry, which is the foundation of the country, the instrument of rejuvenating the country, and the foundation of a strong country, faces new challenges. Especially for the traditional manufacturing industry of chemical industry, resources and environmental constraints have been continuously strengthened. Only follow the guidelines pointed out in Made in China 2025, adhere to green development, drive by innovation, and strengthen the application and promotion of energy conservation and environmental protection technologies, processes and equipment. Promote cleaner production and build a green manufacturing system. Provide the necessary material basis for Chinas science, technology, economic and social development.The project adheres to the spirit of the “13th Five-Year Plan” proposal and follows the guidelines stated in “Made in China 2025”. The use of refinery dry gas and acetic acid as raw materials for vinyl acetate can effectively utilize the waste gas generated by the plant. It can produce vinyl acetate and downstream products with high market demand, and has significant economic and social benefits.Chapter II technological design2.1 OverviewThe project comprehensively utilizes the raw materials of the main plant, converts the dry gas of the refinery into ethylene with high added value and large demand, and then produces vinyl acetate by ethylene. It is planned to build a vinyl acetate plant with a production capacity of 150,000 tons/year. In the production process, we follow the principle of green environmental protection, reduce the discharge of three wastes, and optimize the reaction conditions through various process comparisons to reduce the material and energy losses in the production process, thus achieving low-cost, high-yield, clean production design aims.2.2 Source of raw materialsThe main raw materials used in this project are refinery dry gas, acetic acid and oxygen. The annual consumption of dry gas and acetic acid in the refinery is 266.32 million tons and 122.543 million tons respectively. The normal production of Tianjin Petrochemical can easily meet the raw materials required by the plant, and the cost is low and the source is reliable. Oxygen is supplied by the public works of the park. The auxiliary materials are metal composite oxide catalysts, CTV-V type catalysts, and absorbents such as ethanolamine, potassium carbonate, and the like.Table 2-1 List of raw and auxiliary materialsprojectAnnual consumption / tonssourceMode of transportRefinery dry gas266320Tianjin PetrochemicalPipeline transportationacetic acid122543Tianjin PetrochemicalVehicle transportationoxygen230391Air separation systemPipeline transportationEthanolamine445.53Tianjin Huazheng Chemical Co., Ltd.Vehicle transportationPotassium carbonate13433.04Tianjin Zhengcheng Chemical CompanyVehicle transportationMethane22314.37Simeite Special Gas Co., Ltd.Vehicle transportationEthane34640.23Simeite Special Gas Co., Ltd.Vehicle transportationPd-Au(Pt) catalyst9.00Yurui Chemical Co., Ltd.Vehicle transportationCtv-v type catalyst6.03Yurui Chemical Co., Ltd.Vehicle transportation2.3 Process flowThe production process of this project includes: dry gas demolition section, ethylene exquisite section, vinyl acetate synthesis sectionVinyl acetate exquisite section.Figure 2-1 General flow chart of the project2.3.1 Dry gas removal sectionThe refinery is pressurized and sent to the bottom of the amine absorption tower (T0101).In the amine absorption column, the reaction of hydrogen sulfide, carbon dioxide and monoethanolamine (mea) from the refinery off-gas is removed. The water wash section is designed on the upper part of the amine absorption tower to prevent the tail gas from bearing amine; the concentrator is designed to prevent the tail gas from being liquid.The rich amine solution from the bottom of the amine absorber enters the lean amine heat exchanger (E0101), which is heated by a hot lean amine solution from the bottom of the amine stripper (T0202).The rich amine solution heated to 93 enters the amine desorption column where the acid gas is desorbed from the amine solution. The lean amine liquid from the bottom of the amine desorption column is heat-exchanged with the rich amine solution from the absorption column, and further cooled to a specified temperature by a cooler and pumped into the amine absorption column.The refinery is pressurized and sent to the bottom of the amine absorption tower (T0101).The amine absorption tower consists of three parts, the bottom is the amine absorption part, the middle part is the water wash part, and the top is used as a concentrator. In the amine absorption column, the reaction of hydrogen sulfide, carbon dioxide and monoethanolamine (mea) from the refinery off-gas is removed. The water wash section is designed on the upper part of the amine absorption tower to prevent the tail gas from bearing amine; the concentrator is designed to prevent the tail gas from being liquid.The rich amine solution from the bottom of the amine absorber enters the lean amine heat exchanger (E0101), which is heated by a hot lean amine solution from the bottom of the amine stripper (T0202).The rich amine solution heated to 93 C enters the amine desorption column where the acid gas is desorbed from the amine solution. The lean amine liquid from the bottom of the amine desorption column is heat-exchanged with the rich amine solution from the absorption column, and further cooled to a specified temperature by a cooler and pumped into the amine absorption column.The dry gas from which the carbon dioxide and hydrogen sulfide are removed from the top of the amine tower is sent to the molecular sieve tower for adsorption and dehydration, and is sent to the next stage for treatment after dehydration.Figure 2-2 Flow chart of the mal synthesis section2.3.2 Ethylene exquisite sectionThe refinery dry gas from which acid gas and water are removed is sent to the decarburization four tower (T0201), and the C4 and above components in the dry gas are removed from the decarburization four tower, and the overhead gas is pressurized to 30 bar. It is sent to the demethanizer (T0202), the stripping gas methane is added to the demethanizer, the C2 or C2+ light hydrocarbon component is absorbed by the absorbent, and the overhead gas is used to expand in the expander. The low temperature obtained by the work is used to condense the C2+ component in the overhead gas, and the C2+ component after demethanization is cooled by the gas at the top of the demethanizer, and then cooled to -20 C and then sent through the heat exchanger. In the ethylene rectification column, the absorbed ethylene is separated from the absorbent in the ethylene rectification column (T0203), and the C2+ component discharged from the column is used as an absorbent for the demethanizer, and the overhead gas is condensed and throttling. The expansion system produces low temperature polymer grade ethylene.Figure 2-3 Mal refined section2.3.3 Vinyl acetate synthesis sectionThe circulating gas containing mainly ethylene is boosted to 8 bar by a compressor, and the ethylene obtained in the previous stage is thoroughly mixed and then enters the lower part of the acetic acid evaporation tower (T0301), and is in countercurrent contact with the acetic acid flowing from the upper part of the evaporation tower. The gas which has been saturated with acetic acid vapor comes out from the top of the evaporation tower, is heated by superheated steam to a temperature slightly higher than the reaction temperature, enters the oxygen mixer, and rapidly and uniformly mixes with oxygen to reach the specified oxygen concentration, and strictly prevents local oxygen excess. In case of explosion, The raw material gas derived from the oxygen mixer was added with a spray-like promoter potassium acetate solution in the middle of the piping, and then introduced into the tubular fixed bed reactor (R0301) from the upper portion. The tube is filled with palladium-gold catalyst, and the medium-pressure hot water is taken between the tubes. The raw material gas is contacted with the catalyst at a temperature of 170 and a pressure of 8 bar, and the released reaction heat is absorbed by the hot water between the tubes and vaporized. And produces medium pressure steam. The reaction product contains vinyl acetate, CO2, water and other by-products, as well as unreacted ethylene, acetic acid, oxygen and an inert gas, which are withdrawn from the bottom of the reactor.The reaction product is cooled to about 40 C by the first and second coolers, enters the absorption separation column (T0302), sprays cold acetic acid on the top of the column, and captures the vinyl acetate in the reaction gas, and the unreacted from the top of the column After the raw material gas is pressurized by the compressor, it will re-enter the reaction. A small part will be removed from the water washing tower (T0303), CO2 will be removed for purification, and then washed with acetic acid once in the middle of the tower to remove a small amount of vinyl acetate. The top of the tower is sprayed with a small amount of water, and the acetic acid entrained in the gas is washed away to avoid excessive consumption of potassium carbonate in the CO2 absorption tower. Part of the circulating gas after washing is vented to prevent the accumulation of inert gas, and the rest enters the CO2 absorption tower (T0304), and is in countercurrent contact with 30% potassium carbonate solution under the condition of pressure of 0.7MPa and temperature of 120C. To remove CO2 from the gas. After the absorbed gas, the CO2 content is reduced to about 4%, and the water is removed by condensation drying, and then recycled to the recycle compressor.Figure 2-4 Vinyl acetate synthesis section2.3.4 Vinyl acetate refining sectionSend to the degassing tank. After the pressure is released, the gas dissolved in the liquid is released, compressed by the recovery gas compressor, and sent to the gas for removing carbon dioxide to be sent to the water washing and alkali washing, and the washed gas is compressed and recycled to the table reactor. The liquid reaction liquid in the degassing tank is sent to the rectification reaction section for separation and purification, and impurities such as acetaldehyde, ethyl acetate, water and high boilers are removed to obtain a finished product of refined vinyl acetate. The recovered acetic acid is returned for recycling.A certain amount of liquid is continuously collected from the circulating liquid in the lower part of the absorption separation column, and sent to the preliminary distillation column (T0401) for preliminary separation, and the overhead production liquid is cooled and sent to the phase separation tank (V0402), and the lower layer is mainly Water, a stripper (T0402) is used to recover a small amount of vinyl acetate, and the kettle liquid is discharged as waste water. The upper layer is water-containing crude vinyl acetate, sent to a dehydration tower (T0403) for dehydration, and the extractant glycerin is added to the dehydration tower for extractive rectification, and the bottom bottom production liquid is sent to a glycerin recovery tower (T0404) for recycling glycerin, and then recycled. The top of the dehydration tower is sent to the de-lighting tower (T0405) to remove low-boiling substances such as acetaldehyde, and then removed into the de-weighting tower (T0406) to remove the heavy fraction, and the overhead vapor is condensed to obtain a vinyl acetate product.Figure 2-5 Vinyl acetate refining section2.4 Process innovationRefinery gas processing is one of the important tasks of petroleum refineries. If ethane and ethylene are separated and recovered, polyethylene can be used as raw materials for petrochemical industry and polyolefin plant, and ethane can be used as cracking raw materials for ethylene plant. Therefore, the separation and recovery of light hydrocarbons from refinery dry gas has great economic and social benefits.This project adopts the ethylene production process. The main raw materials are refinery dry gas and acetic acid. The process adopts advanced catalyst with high conversion rate, good selectivity and easy regeneration. At the same time, side line rectification technology is adopted to save energy and reduce consumption, which is in line with the production concept of clean production and green environmental protection.Chapter III Equipment designAccording to the simulation results of Aspen Plus V9.0, combined with the process characteristics of the project, using Aspen, KG-Tower, SW6 and Cup-tower software for the reactor, tower, storage tank, heat exchanger and other equipment in the process. The specific parameters and internal structure were designed, combined with the Zhonglian pump selection software, to select the type of pump that is reasonably applicable. Finally, use the SW6-2011 software to check the selected equipment and select the best equipment.Figure 3-1 KG-Tower simulated tray structureChapter Energy saving and environmental protection4.1 Thermal integrated designThe process uses Aspen Energy Analyzer V9.0 to optimize the design of the heat exchanger network. The calculation process and comparison scheme of the design heat exchanger network are analyzed by the pinch point technology, and the process combination curve diagram before and after the implementation of the heat integration technology is drawn. The pinch point temperature and energy-saving comprehensive economic benefits, through the design of the ancient heat transfer, so that the heat between the various sections can be fully recycled, reducing the pressure on the public works, thereby achieving energy saving and saving investment.Figure 4-1 Curve of total cost-minimum heat transfer temperature difference before optimizationIt can be seen from Fig. 1 that the total cost is the smallest when the heat transfer temperature difference is 17C, so the minimum heat transfer temperature difference is 17C. The process combination curve at this minimum heat transfer temperature difference is shown in Fig. 6, and the total combination curve is shown in Fig. 6.Figure 4-2 Combination process curve before optimizationThe new pinch point is determined by the design and optimization of the heat transfer and heat exchange network between the streams.Figure 4-3 Curve of total cost-minimum heat transfer temperature difference after optimizationFigure 4-4 Optimized process combination curveIt can be seen from the comparison of the total cost-minimum heat transfer temperature difference curve before and after optimization and the process combination curve that as the minimum heat transfer temperature difference increases, the total cost first decreases and then increases. Select the minimum heat transfer temperature difference when the total cost is minimum: 14C.By setting the minimum heat transfer temperature difference to 14C, the energy goal of the heat integration process can be obtained:Figure 4-5 Process energy target after optimizationThe design of the heat exchange network has a large degree of freedom, and the number of solutions obtained is numerous, but a reasonable heat exchange network needs to be screened and optimized. When designing a heat exchange network, it is necessary to consider the possibility of process stream heat exchange, and it is better to take into account factors such as equipment costs in order to obtain the most reasonable heat exchange network. In the Design given by Aspen Energy Analyzer V9.0, the most economical and heat transfer area design is selected for the subsequent optimization process.Heat exchanger network before optimization:Figure 4-6 Full-process heat exchanger network before optimizationOptimized heat exchange network:According to the principle of the minimum number of heat exchangers, it is also possible to go to several heat exchangers. When using a variety of public works heat exchange, the operating costs can be appropriately reduced, but the number of heat exchangers and equipment costs will increase. For example, when cooling water and refrigerant are used for cooling, if the cooling water cooling load is small, the refrigerant can be used directly instead of using two utilities to save equipment costs.Figure 4-7 Optimized heat exchanger networkTherefore, it can be seen that the global optimization heat exchange network saves a large amount of energy consumption for the whole process flow, and the operation cost and the total cost of the global optimization heat exchange network are less than the initial heat exchange network, which greatly saves the factory expenses. It can be seen that heat integration technology is an important means to achieve high-efficiency and high-yield chemical process.4.2 Environmentally friendly designIn recent years, due to the increasing emphasis on environmental protection issues, the production