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Huaibei guoan coal and electricity co - production annual capacity of 200000 tons vinyl acetate project AbstractDirectory Directory11. Project introduction12. Determination of raw materials and products53. Process design64. Energy saving design75. Equipment design106. Cleaner production147. Plant site selection and layout168. Safety environment analysis189. Economic benefit analysis1810. Project summary20 Dalian university of technology vinegar regular team 1/1Huaibei guoan coal and electricity co - production annual capacity of 200000 tons vinyl acetate project Abstract1. Project introductionTable 1 project overviewThe project nameHuaibei guoan coal and electricity combined production annual output of 200000 tons vinyl acetate projectEnterprise naturePrivate enterpriseProject typeChemical engineeringAreaEast China regionProject construction natureNew projects of project construction natureProject construction scale this Project utilizes the acetylene from coal by plasma method the process of xinjiang tianyang tianye company to directly produce acetylene from pulverized coal as raw Material. Then acetylene and acetic acid are used to produce 200,000 tons of ethylene oxide by gas phase method, with a small amount of acetaldehyde and acetone as by-products.This project for the anhui huaibei security project, annual output of 200000 tons of vinyl acetate production by using surplus from thermal power plant of coal production, a new clean technologies: coal acetylene production of high pure acetylene plasma method, vinyl acetate with acetic acid by gas phase method, and the refined purification to optimal grade and by-product ultra high purity of acetaldehyde and acetone at the same time.In the process selection for the synthesis of vinyl acetate in this project, the following judgment is made according to the actual situation in China:1. Chinas resource structure of rich coal and little oil determines that if ethylene is used to produce vinyl acetate, the supply of raw ethylene will be affected by the fluctuation of international oil price, which greatly limits the economic advantages of ethylene. At the same time, according to the existing situation of Chinas vinyl acetate factories, only 10% of the capacity of vinyl acetate is from the ethylene process, so the ethylene route does not have an advantage in China.2, acetylene production of ethylene acetate process route acetylene sources mainly include natural gas, calcium carbide and coal. Because calcium carbide process cant avoid pollution in nature, it is not in line with Chinas future chemical industry planning. Gas technology can meet the requirements on ehs, belong to the new clean technology, but the process of the investment is huge, investigate its reason, is because of Chinas unconventional gas resources are rich, but low degree of development, development cost is high, at present to develop natural gas chemical industry competitiveness is low, so even if have, due to the raw material price is high, in the face of such fierce competition in the market enterprise is difficult to survive; As a typical emerging technology, the plasma coal to acetylene has two key advantages: first, the use of coal to produce acetylene not only solves the fatal problem of high raw material price of acetylene gas phase method, but also makes use of Chinas abundant coal resources according to local conditions; Second, the process is simple, without any catalyst and toxic and harmful substances, the production of cleanliness is very high, fully in line with the future development of Chinas chemical industry requirements. However, the high power consumption of plasma technology and the pollution of coal waste residue become the main obstacles to the popularization of plasma technology and restrict its industrial production. The comprehensive cascade utilization of materials and energy in the process of plasma pyrolysis of coal to acetylene requires extensive cooperation and support from multi-disciplines.At the same time, with the development of Chinas society, on the one hand, the stage of power supply shortage has already passed, and it has entered the era of relative surplus. On the other hand, the installed capacity of wind power, nuclear power, solar power, gas power and other clean energy sources has been increasing, and the utilization hours of coal-fired power units will inevitably continue to decline. In addition, the structural layout of coal-fired power generation is also being optimized and adjusted. Technological progress promotes the increasing proportion of 600MW and 1,000mw ultra-supercritical units in thermal power units, gradually occupying the dominant position in thermal power generation market, especially in the eastern region with developed technology and economy. As a result, more and more 300MW sub-critical units undertake peak load regulation tasks or become peak load regulation units, running under low load or in standby state for a long time. Due to the reduction of unit load, thermal efficiency is bound to decline, which leads to the increase of power generation cost, pollution, thermal power plant survival is increasingly difficult.Based on the above background, on the one hand, the process of plasma pyrolysis of coal to acetylene needs to consume a large amount of electric energy and discharge a large amount of waste residue, gallop and exhaust gas and waste heat in the production process cannot be effectively utilized. It is the key to improve the plasma acetylene process and improve its energy utilization efficiency to find an effective way of energy saving and emission reduction. On the other hand, the subcritical coal-fired power plant of 300MW is gradually becoming a peak-regulating unit, which operates under low load for a long time and has low efficiency. Therefore, it is necessary to find new ways to increase load, so that the generating unit can operate under high load and high efficiency. It will also be an inevitable problem faced by the managers of coal power enterprises in the future. Therefore, the two-generation system has certain potential of complementary energy saving and polygeneration integration. Therefore, this project plans to combine these two chemical/power generation systems to build a coal-based acetylene and power multi-generation system. After the co-production, the two-generation system can complement each others shortcomings and effectively achieve energy conservation and emission reduction of the system. The strategic flow of the cogeneration system is shown in figure 1-1: while the power plant provides hydrogen, pulverized coal and electricity for the plasma device, the plasma device emits gallop gas and coke into the boiler of the power plant to burn and generate electricity, so as to improve the efficiencyEnergy efficiency of cogeneration system. Acetylene-electric polygeneration system not only has the universal characteristics of chemical/power polygeneration system, but also has its own advantages:1. Acetylene - electricity polygeneration system can reduce pollutant emission. Coal of nitrogen, sulfur and other elements in the process of plasma gasification generates manageable HCN and H2S, and removal in the process of acetylene purification, discharge plasma reactor cinder and chi deflated into boiler combustion power generation, not only can reduce coal quantity, and to reduce the desulfurization denitration system load, which can effectively realize the plasma gasification technology for energy conservation and emissions reduction and the efficient clean utilization of coal resources.2. Acetylene - electricity polygeneration system combines electric power production and acetylene synthesis into one. Compared with the independent separate production system, the co-production system shares a set of power plant pulverizing system and hydrogen production system, which not only simplifies the overall process flow of the system, but also reduces the fixed investment of equipment of plasma acetylene system.3. The factory electricity price of the power plant is the lowest in the whole power supply link, which can provide the cheapest electric energy for the plasma device and greatly reduce the operation cost of the plasma device.4. The power plant supplies power to the plasma device while supplying power to the grid, which increases the load of the generator set, makes the generator set run with high power and high efficiency, improves the efficiency of the power plant, and reduces the coal consumption. Moreover, the waste residue and waste gas discharged from the plasma device can be used as fuel to generate electricity, which improves the energy utilization efficiency and effectively reduces the fuel cost of the boiler.5. Acetylene-electric power polygeneration system is a parallel-type polygeneration system, which can realize flexible production of acetylene and electric power. Coal-fired power plants can adjust the output of electric power and acetylene at any time according to the requirements of grid load dispatching.FIG. 1 flow diagram of coal - electricity cogeneration systemThis project adopts the innovative idea of combined production of coal and electricity to maximize the utilization of resources, and adopts the advanced clean production process - acetylene produced by plasma coal process, which meets the green and clean production requirements of the chemical plant in made in China 2025.2. Determination of raw materials and productsThis project is built in huaibei, anhui province, and USES the local coals in huaibei for plasma pyrolysis. The relevant literature shows that the coals that meet the requirements of low oxygen content, more active chemical properties, 25% 40% volatile content, weak coking and higher H/C conditions are suitable for acetylene production from plasma pyrolysis coal. Through evaluation and comparison, anhui huaibei coal meets the requirements of cracking reaction. Acetic acid, another major raw material of the project, was purchased from huainan kedi chemical technology co., LTD.The industrial analysis of huaibei coal is shown as follows:Table 2 analysis of anhui huaibei coal industryCoal originVdaf/%Ad/%Mad/%(C)/%(H)/%(0)/%H/CAnhui huaibei33.876.313.3787.326.126.560.07In order to maximize economic benefits and take into account the principle of environmental protection, the process produces high purity acetaldehyde and acetone in addition to the main production of vinyl acetate. According to the investigation of this project, both kinds of high purity by-products can be sold locally, which greatly reduces the cost of sales and transportation and improves the sales efficiency.Table 3 products and specifications of this projectSerial number Product Specification (%) output Remarks1Vinyl acetate99.96200440tMain products2Acetaldehyde99.999802tThe by-product3Acetone99.99993272tThe by-product4High calorific value cinder230780tThe by-product3. Process designThis project after product selection and technology scheme comparison, the coal industry company in xinjiang day plasma acetylene process and acetylene gas phase synthesis of vinyl acetate process, designed the system of plasma acetylene section, acetylene thick section, vinyl acetate synthesis section, materials circulation section and refined products section, has realized the steady state simulation and optimization of the whole process.The flow chart is shown in FIG. 1. See the chemical process and system in chapter 4 of preliminary design specification.FIG. 2 flow chart Figure 3 Aspen Plus process simulation diagram4. Energy saving designOptimization of heat transfer networkIn this project, there are many designed public works. In order to make full use of Energy, this project designed an optimal cold and hot flow unit matching scheme by using Aspen Energy Analyzer software, according to the clip design method and the actual situation, and conducted flow unit matching. Meanwhile, the return process simulation and PID drawings of the optimized heat exchange network are compared and analyzed to get the final scheme. See Aspen process simulation source file and PID drawings for details. The matching scheme of heat exchange network for the whole plant is shown in figure 4.FIG. 4 Matching Scheme of Heat Exchange Network in the PlantAfter the optimization of heat exchange network by thermal integration, a total of 20.8MW of cold engineering and 29.2MW of hot public engineering are needed. Compared with before optimization, the energy saving is 15.3 MW.Variable pressure + three effect distillation systemFIG. 5 flow chart of variable pressure + three effect rectificationThe purpose of variable pressure is to achieve better separation effect - the mass concentration of acetone by-product is increased from 90.6% to 99.99%, and the purpose of multi-effect is to achieve the energy integration of the system to reduce energy consumption - the total energy saving is 66.4%. The organic combination of the two can not only achieve the efficient separation of products, but also greatly reduce the energy consumption level.Table 4 comparison between ordinary distillation and variable pressure + three-effect distillation schemeProjectOrdinary towerDistillation processVariable pressure + three effect distillation processHigh pressure towerMedium pressure towerLow pressure towerTower pressure/bar11.40.80.1Total condenser load /kw723.100205.9Total reboiler load /kw833.1322.400The total energy consumption/kw1556.1528.4Equipment investment/ten thousand yuan361.8325.8Operating cost/(ten thousand yuan/year)55.719.1Comprehensive cost/(ten thousand yuan/year)73.725.3Acetone purity90.9%99.99%Energy saving: 66.4%, comprehensive cost saving of 484,000 yuan/year, equipment investment saving of 360,000 yuan.In conclusion, compared with ordinary three-column distillation, the scheme of transformer pressure + three-effect distillation to produce ultra-high purity acetone can save energy consumption, reduce comprehensive cost and investment, and greatly improve product purity and quality. Therefore, this project decided to adopt the scheme of variable pressure + three-effect rectification to produce acetone.Reactor waste heat recovery systemDue to the existence of special reactors, this project has certain particularity in the utilization of thermal energy. The plasma reactor is an ultra-high temperature reactor, with a normal operating temperature of up to 3500k-4000k. In addition to recovering most ultra-high grade heat by itself, there is also a part of high temperature (1000K) heat that cannot be recovered by itself. Acetylene gas phase synthesis of vinyl acetate reaction is an exothermic reaction, the reactant feed and reaction temperature are both 473K, so this part of the heat released from the reaction can also be recycled. In view of the above two points, this project has established a special waste heat recovery system to recover waste heat with utilization value.Waste heat recovery in the reactor is shown in the figure below：Table 5 waste heat recovery heat screeningThe reactorTemperature grade Waste heat (kw)Can you useTotal recycling capacity (kw)Thermal plasmaThe reactor8000.71104Can1.071041500.12104Can not beVAC synthesisthe reactor2600.36104CanThrough the waste heat recovery system, it basically meets all the high pressure and medium pressure steam demand of distillation tower and heat exchanger and most of the low pressure steam demand, greatly reduces the energy consumption level of the system, and saves the thermal public works cost of 93.43 million yuan every year for the enterprise.5. Equipment designIn the design process of this project, the detailed design of acetaldehyde refining tower, vinyl acetate synthesis reactor and other equipment was carried out, and the selection of heat exchanger, pump, compressor and other equipment was carried out. See typical equipment design and type selection and reactor design specification for details.Fluidized bed reactor with dual disk gas distributorIn this project, in the vinyl acetate synthesis reactor, raw gas is fed through the upper pipe mouth. The reactor barrel diameter is 3000mm, which is relatively large, and the raw gas fails to be evenly distributed in the device. Therefore, this project USES a double-disk gas distributor, which is installed inside the device. The distribution appliance has the advantages of simple structure, convenient processing and installation, and great flexibility of operation, which can effectively save the cost of manufacturing, operation and maintenance.The schematic diagram of the dual-disk gas distributor is shown in FIG. 6：FIG. 6 schematic diagram of two-tray gas distributorThe fan - shaped blades adjacent to two distribution disks are interlaced with gas channels. The distribution disk is connected with the distribution disk by the supporting shaft, and each distributing disk is arranged in a coaxial order on the supporting shaft.A baffle plate is set on the gas flow channel, so that the process gas coming in from the inlet pipe is blocked by the baffle plate, preventing the gas from directly penetrating a small area in the center of the equipment and flowing out from the outlet. The fan-shaped blades arranged horizontally play the role of drainage and flow diversion. On the one hand, the gas flows along the extension direction of the blade, and on the other hand, t