0-摘要1-设计文档集Abstract-2010

Design of deep desulfurization unit for petroleum refining tail gas in Zhenhai Refining & Chemical Company and 75kt/year Methyl Mercaptan ProjectDirectory1.Project introduce12. Market analysis of methyl mercaptan23Production technology overview33.1 The determination of raw material33.2 Process to determine43.3 Process description43.3.1 Raw material pretreatment53.3.2 Synthesis of methyl mercaptan73.3.3 Product refinement74. The clean production105. Factory design116. Energy-saving design116.1 Heat integration116.2 Heat pump distillation126.3 Double effect distillation137. Safety design138. Dynamic simulation149Technical and economic indicators1710Conclusion18191.Project introduceThe project is designed to take into account the economic benefits, green and clean production concept. In considering the economic benefits at the same time, actively use energy-saving environmental protection production technology, such as double-effect distillation, heat pump distillation, pinch analysis, waste treatment and taking into account the economy and environmental protection. And using Aspen and other software to complete the process plan selection, process route design, process simulation and optimization, heat transfer network optimization and heat exchanger design. Using CAD to draw the process flow diagram (PFD), piping and instrumentation diagram (PID), key equipment assembly drawings, and workshop equipment layout. While using the Sketch Up to design three-dimensional workshop and 3D factory. The reactor structure was improved and optimized by using Fluent software. Adobe After Effects and Adobe Premiere software are used for post-processing animation.All designs of this project follow the HSE concept. HSE is short for Health, Safety and Environment management. Its core values are responsibility, care, sharing and communication. The concept of project safety and environmental protection runs through the whole plant.2. Market analysis of methyl mercaptanAs an important organic chemical product, methyl mercaptan is mainly used in synthetic pesticides, medicine, synthetic materials, feed and so on. Due to the rapid development of methionine synthesis industry in recent years, the industrial production of methyl-thiol has gradually attracted peoples attention. Combining the chemical and petroleum refining emit large amounts of hydrogen sulfide gas causes serious pollution to the environment and the present situation of the domestic methanol market serious saturation, hydrogen sulfide methanol synthesis of methyl mercaptan process become the field of research hot spots. Hydrogen sulfide with methanol under contains potassium tungstate activated alumina catalyst, reaction of methyl mercaptan and acrolein again after addition reaction of hydrolysis can get DL - methionine, has the reactants, the yield is high, the three wastes easy processing, low production cost, strong product competitiveness, etc.In recent years, the feed industry in China has developed rapidly, and the demand for methionine is increasing rapidly. The market of methionine is active, which partly stimulates the market of methyl mercaptan. At present, only some factories in China have developed the industrial project of methanol production of methanol, which produces a small scale of hydrogen sulfide methanol, which is not high and the benefit is poor. The end of the 20th century in Shandong Xing Wu group for its products of liquid hydrogen sulfide for downstream products choose the hydrogen sulfide synthesis method of methyl mercaptan methanol production projects, after a lot of trial test and the catalyst research and development, the production capacity of 2004 with an annual output of 3000 t of methyl mercaptan and methyl sulfide 500 t. In order to solve the problem of acid gas containing hydrogen sulphide, Nanjing chemical industry corporation has built a set of 7 kiloton methanol unit and an annual production of l0kt methionine device. The rapid and steady development of the domestic methanol industry in recent years can improve the situation of domestic demand in some way. With the further increase of environmental protection in China, other synthesis routes of methyl mercaptan are severely restricted due to environmental problems. Therefore, the domestic production of methanol in the production of the methanol production will have a great market prospect.3Production technology overview3.1 The determination of raw materialThe main raw materials used in this project are hydrogen sulfide derived from the oil refining unit IV diesel hydrogenation device and V wax hydrogenation device from Sinopec Zhenhai Refininig &Chemical Company. Hydrogen sulfide is H2S is highly toxic substances, and cannot be emissions, not easy to store and transport, hydrogen sulfide and sulfur important resources at the same time, recovery of hydrogen sulfide in waste gas is not only the requirement of environmental protection and resource recycling requirements.The project also needs methanol, which is an important and high demand basic organic chemical raw material, and also a new kind of clean energy. The raw material of our factory for the production of methyl mercaptan methanol is provided by Hongxin Chemical Company in Zhenhai, Ningbo. This company with independent property rights of storehouse library, can deposit more than two thousand tons of liquid chemical storage tanks, four vehicles, dangerous goods transport vehicle, the other chemical terminals in Ningbo port has a special exclusive store more than one thousand tons of methanol storage tank. Methanol sells about 45,000 tons per month, which is the designated supplier of methanol procurement.In conclusion, the sources of raw materials are adequate and guaranteed.3.2 Process to determineAccording to the temperament conditions of raw materials, the content of hydrogen sulfide in raw materials, the content of CO2, the content of water and light hydrocarbon, therefore, hydrogen sulfide gas needs to be purified. The purification method of hydrogen sulfide mainly includes the alcohol amine method, the cold methanol washing method, the NHD method and so on. The process of hydrogen sulfide and methyl mercaptan is: hydrogen sulfide - methanol gas phase synthesis and high sulfur gas synthesis.By comparing and comparing various technical indexes and advantages and disadvantages of each process, the pure choice of MDEA method for hydrogen sulfide is selected, and the MDEA method has good selectivity for the purification of hydrogen sulfide. The concentration of the solution is higher, the acid gas load is large, and the circulation is small. Low renewable energy consumption and low operating cost; Poor liquid is corrosive, low in vapor, small evaporation loss. The synthesis of methyl mercaptan hydrogen sulfide - methanol method choice, the law has the process easy, cheap raw materials high yield, good product quality, methanol conversion rate can reach 90%, methyl mercaptan highest yield was 98% (typically to 92%), by-product methyl sulfide can under the effect of catalyst into methyl mercaptan. It is easy to deal with, low production cost and other advantages.3.3 Process descriptionhis process is made from sulfur-containing exhaust gas produced by petroleum refining, and purified H2S by means of MDEA solvent absorption, desorption and two-stage compression condensation, H2S and methanol reaction synthesis product methyl mercaptan. The main process includes pretreatment of raw materials, H2S methanol synthesis of methyl mercaptan section, product refining three sections.Figure 3-1 process material integration3.3.1 Raw material pretreatmentRaw materials containing sulfur fumes from the bottom into the absorption tower, gas from the bottom up and top into the MDEA absorber countercurrent contact, fully absorbed, the top discharge alkanes, which are not absorbed a large amount of carbon dioxide and a small amount of hydrogen sulfide (overhead effluent goes together with the next section of residual air pressure swing adsorption), bottom absorption liquid into analytic tower, the bottom of MDEA solution cycle back absorption tower, tower gas out after two stage compression and condensing water vapor, hydrogen sulfide (95%) in isolated methanethiol synthesis section.Figure 3-2 process flow chart of raw material pretreatment (1)Figure 3-3 process flow chart of raw material pretreatment (2)Figure 3-4 process flow chart of raw material pretreatment (3)3.3.2 Synthesis of methyl mercaptanFrom hydrogen sulfide thick section of hydrogen sulfide and methanol by supercharge preheating into methanethiol synthesis reactor with catalyst and reactor for fixed bed reactor, the mixed gas out of the reactor, through the two levels of partial condensation, separating the product gas into water condensate containing methanol, water, and containing hydrogen sulfide and methyl mercaptan, sulfide, methyl ether organic condensate. Not residual air condensation, from residual air absorb methanethiol by methanol washing, after washing with a section on the absorber tower of gas mixture together into the tower, the pressure swing adsorption (psa) isolated from the hydrogen sulfide gas cycle back to preheat pressurized hydrogen sulfide methanol phase, carbon dioxide (contain a small amount of paraffin) isolated from the urea plant.Figure 3-5 process flow chart of the synthesis process of methyl mercaptan3.3.3 Product refinementPortion of a section of the two-stage condensation of two strands of condensate water, organic condensate with methanol washing liquid into the stripping tower, the tower of hydrogen sulfide gas cycle back to preheat pressurized hydrogen sulfide and methanol phase, bottom mixture into the extraction column, and water extraction, get methyl mercaptan sulfur ether mixture, the tower bottom after further rectification of methanol and water, methanol isolated loop onto a section of methanol washing tower, isolated part of the water cycle to this section of the extraction column, another part of the sewage treatment plant. The top of the tower was separated by the distillation column, and the top of the tower was obtained by the main product methyl mercaptan.Figure 3-6 flowchart of product refining section (1)Figure 3-7 flowchart of product refining section (2)Figure3-8 flowchart of product refining section (3)Figure 3-9 flowchart of product refining section (4)Figure 3-10 flowchart of product refining section (5)4. The clean productionThis is a project of Design of deep desulfurization unit for petroleum refining tail gas in Zhenhai Refining & Chemical Company and 75kt/year Methyl Mercaptan Project. Not only to achieve the treatment of tail gas, but also realize the resource utilization of hydrogen sulfide, with a petrochemical and chemical industry 12th Five-Year development plan in the promotion of Chemical Industrial Park, industrial agglomeration, effective use energy emissions centralized management and other advanced production mode, to achieve waste reduction and recycling, construction of circular economy industrial chain. The project uses multiple cycles to recycle unreacted raw materials, and uses double effect distillation and heat pump distillation to realize the rational utilization of energy. This project is important to the sustainable development of economy and environment protection.All the items of wastewater, waste gas and waste have taken the feasible treatment method of treatment. Emission index of treated wastewater can reach the national standard; urea treatment plant waste gas carbon dioxide concentration high cocoa plant feeding; solid waste recycling after pretreatment to return to the dealer. The process conditions are moderate, the equipment are safety and standards. And ensure that production is safety.5. Factory designConsider the raw material, market, traffic, policy, environment capacity and so on various aspects factor, siting in maoming city of guangdong province maoming petrochemical industrial park north district organizations. On this basis, according to relevant national industry standards, combined with the actual situation, the design team used Auto CAD to the factory layout, workshop layout and piping layout, as shown in the figure below:Figure 5-1 layout drawing6. Energy-saving design6.1 Heat integrationThis project involve a lot of public works. In order to make full use of energy, this project by using the Aspen Energy Analyzer software, according to the pinch design method, combined with the actual situation of the factory arrangement, stock flow matching, aiming at economic and Energy saving optimization, through the best selected minimum 6 after heat transfer temperature difference of heat exchange network design, further manual optimization, combined with the artificial, devised a optimal matching scheme of cold and hot flow stocks. At the same time, the optimized heat exchanger network is returned to the process simulation and PID drawing. See the Aspen process simulation source and PID drawing.Finally with the results as follows:Figure 6-1 heat exchange network optimization scheme6.2 Heat pump distillationIn order to reach the goal of saving energy and reducing consumption, we separate the parsing using “heat pump distillation separation technology”, according to our choice of tower equipment and characteristics of the separation of task, select the heat pump distillation, the calculation and energy saving effect is obvious, energy-saving shown in the table below:Table 6-1 Energy saving effect formHeat energy consumption of the utility/KWEnergy consumption of cold utility/KWThere is no heat pump distillation22997.767631958.3676Including heat pump distillation681815778.6Energy saving70.354%50.628%6.3 Double effect distillationIn order to reach the goal of saving energy and reducing consumption, not only save a heat exchanger, also part of heat can be recycled, according to our choice of tower equipment and characteristics of the separation of task, choose the double effect distillation, through calculation, the energy saving is as follows:Table 6-2 Energy saving effect formHeat energy consumption of the utility/KWEnergy consumption of cold utility/KWThere is no double effect distillation10246.0418935.2341Including double effect distillation681815778.6Energy saving50.28%20%7. Safety designSafety is the most important consideration in industrial production, the project is to implement the “safety first, prevention first, comprehensive treatment”the guiding ideology, design from top to bottom five safety level.First of all, the whole plant establishes a unified HSE management system to integrate health, safety and environment into a comprehensive management system. From the projects HSE management policy, management mechanism, human resources, material security and compliance with the laws and regulations, carry out the whole system design.Secondly, the project production adopts advanced essential safety concept, which can reduce the possibility and harm of accidents from the aspects of process design, operating conditions, storage transportation and equipment selection.Again, this project in the production of raw material product hydrogen sulfide and methyl mercaptan and methyl sulfide are inflammable and explosive toxic dangerous goods, the project is to strengthen the material storage and transportation management, and improve the leakage prevention measures.Then, this project strictly adheres to the fire prevention code of petrochemical enterprises and the fire protection code of architectural design in the whole plant, so that the design can be standardized. During normal operation, safety training is adopted to improve employees safety awareness, standardize safety operation and reduce the probability of human accidents.In the end, the project developed a comprehensive contingency plan for the accident, and used the Risk System software to simulate the leakage accident to provide the basis for the formulation of emergency measures.8. Dynamic simulationAspen plus is the process of steady state simulation, is a factory after continuous operation, the process conditions are in a stable, logistics parameters in a certain range in a stable value, therefore the Aspen plus simulation is ideally get all kinds of logistics information. But in actual production, inevitably will face due to equipment malfunction or other process conditions change (open), parking process cause process under transient operating conditions, which affects the yield and purity of the product.Optimization and innovation of methanol synthesis reactor based on fluent software:The distribution of gas in the tower (especially the initial distribution of imported airflow) has great influence on the separation efficiency and product quality of the large packing tower. A good gas distributor can not only weaken the uneven distribution caused by the flow, but also greatly reduce the resistance of the system. Because this technology reactor using multistage packing reactor, diameter is larger, the reaction is exothermic reaction, directly using horizontal intake results in uneven distribution of gas, easy to cause local temperature is too high, produce coked catalyst deactivation, incomplete reaction in the increased costs of production. Therefore, it is necessary to distribute the air intake evenly, increase the reaction yield and improve the economic efficiency. Before optimization, the picture is as follows:Figure 8-1 no air distributor fluid distribution diagramTherefore, with a compari