02-Design Abstract1 设计文档Design Abstract

中国石化四川维尼纶厂年产25万吨醋酸乙烯项目附录常州大学 我们都队! 团队团队成员：郭娜 杨晓刚 周雨婷 周宓 朱毅诚指导老师：马江权 薛冰 高晓新 徐松 周满Design Abstract2019“东华科技-恒逸石化杯”第十三届全国大学生化工设计竞赛常州大学 我们都对团队 目录Chapter I Project Profile31.1 entry name31.2 Project nature31.3 Location and area of the project to be built31.4 Significance of Construction3Chapter II Selection and Introduction of Process Flow52.1 Overview of process52.2 Introduction of Process Route5ChapterIII Energy Conservation and Innovation133.1 Innovation of process plan133.2 Innovation of Reaction and Separation Technology133.2.1 New Process of High Efficiency Reaction133.2.2 New Technology of High Efficiency Separation153.2.3 Chemical absorption and desorption193.3 Energy-saving Design and Innovation203.3.1 Low energy consumption in the whole process203.3.2 Construction of Optimized Heat Exchange Network213.3.3 Energy-saving effect213.3.4 Heat pump distillation technology22Chapter IV Environmental Protection244.1 Three Wastes Discharge and Control Measures244.1.1 Waste Gas Source and Control Measures244.1.2 Source of Wastewater and Treatment Measures254.1.3 Source of Waste Slag and Control Measures294.3 Noise processing304.4 green31Chapter V Plant Area Selection325.1 Site Selection325.2 Plant layout32Chapter VI Economic Evaluation34Chapter VII Summary37Chapter I Project Profile1.1 entry nameSinopec Sichuan Vinylon Plant 250,000 t/a Vinyl Acetate Project1.2 Project natureThe objective of this project is to design a utilization branch plant for producing vinyl acetate from acetylene and acetic acid for sinopec vinylon plant in sichuan. This project comprehensively utilizes the high purity acetic acid and high purity ethylene obtained by sinopec sichuan vinylon factory, in which the mass fraction of acetic acid is 95% and that of acetylene is 99.9%. The resource utilization of acetylene and acetic acid is a task of great practical significance. 1.3 Location and area of the project to be builtSinopec sichuan vinylon factory in changshou district, chongqing 1.4 Significance of ConstructionFor China, the annual demand growth rate of vinyl acetate is estimated to be about 5% from 2010 to 2020, and the annual demand of vinyl acetate will reach 2.7 million tons in 2020. The domestic strategy of processing vinyl acetate into polyvinyl alcohol cannot adapt to the world market competition. In 19831995, the development and application of vinyl acetate, polyvinyl alcohol and their downstream products were gradually paid more attention after the domestic chemical fiber products were seriously unsalable and the production of vinylon declined seriously. According to forecasting, the speed that our country demands to coating next few years increases ceaselessly, and the steady development of industry of electron, papermaking, medicine, shoe, fine chemical industry, also can push the development of product of downstream of acetic acid ethylene and application further.In addition, In the future, vinyl acetate can replace methyl acrylate as a copolymer of acrylic fiber modification. Because of its good fiber properties, it has developed rapidly in recent years. China is a big textile country with an annual output of 500,000 acrylic fibers.About 300,000 tons of acrylic fibers are imported annually. There is a great space for acrylic fibers to develop. If vinyl acetate copolymer is used in domestic acrylic fiber products, it will be a big market for vinyl acetate. Based on the analysis of market, cost, by-product treatment, dependence on other raw materials and technical maturity, we use acetylene and acetic acid to produce vinyl acetate. This project is not only conducive to the healthy development of Sichuan Vinylon Plant of Sinopec Group, but also can achieve certain economic and social benefits. Benefit.Chapter II Selection and Introduction of Process Flow2.1 Overview of processEthylene acetate was produced by acetylene gas phase method. Mature technology, lower investment cost and operation cost, operation during the catalyst performance is stable, easy to control, the plant covers an area of small, fundamentally solve the CO2 pollution, equipment corrosion from acid, can be selectively to obtain high purity and high yield, vinyl acetate unreacted materials can be recycled and high economic benefits. 2.2 Introduction of Process Route1. Vinyl acetate synthesis sectionThe first section of this process is the synthetic section of vinyl acetate. The molar feed ratio of acetylene and acetic acid was 4:1. And strict control, so that acetylene in the explosion limit of feed, to ensure safe production process. Acetic acid is vaporized by acetic acid evaporator and mixed with acetylene to react in fluidized bed reactor. Under the condition of 200 and 2 bar, zinc acetate - activated carbon catalyst was used to generate ethylene acetate, acetaldehyde, acetone and other main by-products. After compression and condensation, it enters the three-tower degassing system, the crude acetylene gas at the top of the tower is refined in the acetylene refining section,and the liquid liquid in the tower is refined in the ethylene acetate refining section .Figure 2-1 Flow chart of vinyl acetate synthesis process (A)Figure 2-2 Flow chart of vinyl acetate synthesis process (B)Figure 2-3 Flow chart of vinyl acetate synthesis process (C)2. Acetylene Refining SectionThe first section of this process is the synthetic section of vinyl acetate. The molar feed ratio of acetylene and acetic acid was 4:1. And strict control, so that acetylene in the explosion limit of feed, to ensure safe production process. Acetic acid is vaporized by acetic acid evaporator and mixed with acetylene to react in fluidized bed reactor. Under the condition of 200 and 2 bar, zinc acetate - activated carbon catalyst was used to generate ethylene acetate, acetaldehyde, acetone and other main by-products. After compression and condensation, it enters the three-tower degassing system, the crude acetylene gas at the top of the tower is refined in the acetylene refining section, and the liquid liquid in the tower is refined in the ethylene acetate refining section. Figure 2-4 Flow chart of acetylene refining process (A)Figure 2-5 Flow chart of acetylene refining process (B)Figure 2-6 Flow chart of acetylene refining process (C)3. Vinyl acetate refining sectionThe third working section of this process is ethylene acetate refining working section. From vinyl acetate in the first stages of coarse product and the second section after the mixture of acetic acid and vinyl acetate into coarse tower, tower kettle get high purity acetic acid to circulation, gas phase into the acetone refining tower, tower top and get high purity acetone in the tower, tower kettle liquid continue to refined refined, vinyl acetate and vinyl acetate in refined tata still get classy article vinyl acetate. Figure 2-7 Process flow chart of vinyl acetate refining section (A)Figure 2-8 Process flow chart of vinyl acetate refining section (B)Figure 2-9 Process flow chart of vinyl acetate refining section (C)4. Carbon dioxide recovery sectionThe fourth section of this process is the carbon dioxide recovery section. From the second section of carbon dioxide and acetylene mixture condensation, distillation and dehydration, get water - free carbon dioxide and acetylene mixture. The mixture then enters the adsorption column to remove the carbon dioxide to obtain high purity acetylene. The adsorbent was then analyzed to obtain industrial grade carbon dioxide by-products. Figure 2-10 Process Flow Chart of Carbon Dioxide Recovery Section (A)Figure 2-11 Process flow chart of carbon dioxide recovery section (B)Figure 2-12 Carbon dioxide recovery process flow chart (C)3/ 38Figure 2-13 Process Flow Chart of Carbon Dioxide Recovery Section (D)Figure 2-14 Process Flow Chart of Carbon Dioxide Recovery Section (E)ChapterIII Energy Conservation and Innovation3.1 Innovation of process plan This process directly USES high purity acetylene and acetic acid as raw materials to synthesize main by-products such as vinyl acetate and acetone. The resource utilization innovation of this process is as follows:1. In the past, vinyl acetate is usually synthesized from acetylene ethylene produced by calcium carbide natural gas, and the synthetic vinyl acetate often contains other components, which will affect the subsequent production. This project USES dry purity acetylene and acetic acid as raw materials to directly synthesize vinyl acetate to avoid the influence of too many impurities on the subsequent production.2. Vinyl acetate is mainly used in the production of plastic film, clothing, cable, etc. At present, there are many domestic vinyl acetate manufacturers, such as sinopec, with a capacity of 3.5 million tons per year. But still in short supply, in the application of high purity vinyl acetate products, medical supplies account for a large part, the purity of vinyl acetate products produced in this project can meet the requirements of medical supplies. 3.2 Innovation of Reaction and Separation Technology3.2.1 New Process of High Efficiency Reaction 3.2.1.1 Two-stage Desuperheated Fluidized Bed ReactorDue to the gas-solid heterogeneous reaction, there are two main reaction devices for acetylene gas phase synthesis of VAc: fixed bed and fluidized bed. In the reactor selection process, the following characteristics of the reaction system are mainly considered:1. The heat release of the main reaction is 110.5 kJ/mol, and the activation energy is about 72 kJ/kmol, while the heat release of the main side reaction acetylene is 150.14 kJ/mol. Timely withdrawal of reaction heat makes the reaction stable at the appropriate temperature, which is conducive to improving the conversion rate and selectivity of the reaction, and reducing the catalyst deactivation caused by local overheating.2. The reaction system USES zinc acetate catalyst. Although the average life of the catalyst is 1.52 years, some catalysts cannot be recovered due to wear and tear. Therefore, in order to ensure the continuous operation of the plant with efficient catalytic capacity, fresh catalysts are added daily according to the amount of loss.In conventional fixed bed reactors, the following problems exist1. Acetylene and acetic acid reaction to produce vinyl acetate is a strong heat release reaction, when the conversion rate is high, if the heat cannot be removed in time, it will lead to local deactivation of the catalyst, or even cause a parking accident.2. Small diameter particle catalyst cannot be used, otherwise the fluid resistance increases, affecting the normal operation, so that the active surface of the catalyst can not be fully used.3. Serious loss of catalytic auxiliaries at the end of the reactor leads to decreased catalytic activity, so it is necessary to stop periodically to replace the deactivated catalyst.Based on the analysis of the above reaction characteristics and the detailed introduction of different types of reactions in the first chapter of this paper, this project chooses the fluidized bed reactor. The main advantages are as follows:1. Due to the small particle size of the catalyst, the catalyst with a certain volume has a larger contact surface, which is conducive to heat and mass transfer.2. The catalyst particles are in a constant state of motion in the fluid, and the interface of gas-solid phase is constantly stirred to update the phase interface, improve the heat and mass transfer coefficient, make the temperature distribution in the bed uniform, avoid local overheating, not only increase the life of the catalyst, but also improve the product quality.3. In the process of operation, some old catalysts can be easily removed and some new ones can be added to ensure that the activity of catalysts decreases slowly and the operation cycle is prolonged.The fluidized bed reactor mainly consists of the following parts: the body part, the internal components, the distributor, the water removal heat system and the internal and external cyclone separator. The activated carbon with an average particle size of 0.453 mm supported zinc acetate catalyst to achieve high efficiency. 3.2.1.2 Use of High Efficiency CatalystsThis project adopts zinc acetate/activated carbon catalyst in the synthesis reaction of vinyl acetate, which is a solid acid catalyst. Using bismuth carbonate as a catalyst, the bismuth content at about 10 PPM can effectively increase the catalytic activity and inhibit the formation of acetylene polymer. Imported coconut shell carbon is selected as the carrier of activated carbon, which has a microcrystalline structure and irregular microcrystalline arrangement, with large mechanical strength, good wear-resisting performance, stable structure and small adsorption energy required, which is conducive to regeneration. Moreover, activated carbon catalyst has developed pores and large specific surface area, which can fully contact with gas, and has an efficient catalytic effect in gas reaction. After it is deactivated, it can be sent to the qualified processing factory for recycling and regeneration, so there is basically no three wastes in the production process. 3.2.2 New Technology of High Efficiency Separation3.2.2.1 High Efficiency Adsorption Separation of Acetylene/Carbon DioxideIn order to respond to the green development of low-carbon environment in China and meet the requirements of low-carbon emission of 2025 made in China, this process adopts advanced absorption and desorption process to improve the purity of unreacted acetylene in the process of rational utilization of carbon dioxide in order to meet the requirements of recycling. At the same time, carbon dioxide will be absorbed and made into green agricultural products. Improve product utilization, reduce carbon emissions and reduce environmental pressure.Because the pore size can be adjusted and the pore wall can be functionalized, micro-porous metal organic frameworks (MOFs) have great prospects as materials for gas separation and purification, and have become one of the frontier research hotspots in the field of chemical materials. In the past 20 years, a large number of porous MOFs have been used for different gas separation and purification, from less challenging (such as CO2/N2 and CO2/CH4) to more challenging mixture (such as acetylene/ene and alkene/alkane) separation. Because the physical properties of acetylene and CO2 are very similar and their kinetic diameters are almost the same, it is very difficult and challenging to design porous materials for efficient purification of acetylene and CO2. Xiangshengchang Research Group of Fujian Normal University, based on the pore size adjustability of ACS-MOFs and the recognition of acetylene by Lewis base sites on the pore wall, proposed a new design idea of developing PSP into a MOFs bifunctional optimization. The obtained material is a challenging C2H2/CO2 mixture separation meter at room temperature and atmospheric pressure. It shows excellent performance. ReferenceFig. 3-1 FJU-90a Adsorbent Adsorption Isotherm of Fujian UniversityFig. 3-2 Penetration Curve of Five CyclesIn this project, two parallel adsorption and desorption towers are designed, which are filled with FJU-90a adsorbent developed by Fujian University. The FJU-90a catalyst with reduced pore size can adsorb up to 180 cm3g-1C2H2 at room temperature, but much less CO2 (103 cm3g-1). The simulated column penetration analysis shows that FJU-90a has a mass separation capacity of 5.10 mol kg-1 for 50% C2H2/CO2, which is the highest reported value at present, as shown in Fig. 3-1. In addition, the actual penetration experiment further verified that the material had excellent separation and purification performance for 50%:50% C2H2/CO2 mixture, and the performance did not decrease significantly after five cycles, as shown in Figure 3-2. After adsorption, the gas produced at the top of the tower is high purity CO2 in 30 minutes. After 30 minutes, it is switched to vacuum pump for adsorbent regeneration. When regeneration, the adsorbent FJU-90a molecules adsorbed inside the adsorbent dissipate under negative pressure to achieve adsorbent regeneration. The settings of the adsorption and desorption tower are shown in Fig. 3-3.Figure 3-3 Adsorption and Desorption Column3.2.2.2 Azeotropic distillation technologyAzeotropic distillation was used in the refining tower of vinyl acetate.In the traditional process of producing vinyl acetate from acetylene, ordinary distillation is usually used to purify vinyl acetate. Azeotropic distillation and nested heat pump distillation are used in this process, which greatly reduces the energy consumption of the refining tower in the traditional process.Acetic acid-vinyl acetate-water is a ternary azeotropic system. According to the phase diagram, the operating pressure of the separator at the top of azeotropic distillation column is 0.332 bar. The process of vinyl acetate refining tower as shown in the figure shows that the gas phase at the top of the tower is condensed by a condenser and then separated into a phase separator. The water phase is recovered and the organic phase is refluxed. The high yield vinyl acetate is obtained in the reactor (the mass fraction is 99.99%). Figure 3-4 VAC/H2O/CH3COOH Azeotropic phase diagram3.2.2.3 Chemical absorption and desorption In order to respond to the national energy saving and emission reduction policy and improve resource utilization, MEA was used to separate the gas phas