【作者】 秦昌；

【导师】 李振民；

【作者基本信息】 青岛科技大学 ， 化学工程， 2009， 硕士

【摘要】 苯氨基甲酸甲酯（MPC）是非光气法合成二苯基甲烷二异氰酸酯（MDI）的重要中间体。目前利用碳酸二甲酯（DMC）和苯胺合成MPC的工艺研究较多,该工艺原子利用率高,环境友好,具有很好的发展前景。1.利用苯胺和DMC为原料,无水醋酸锌为催化剂,在高压反应釜中,170℃、1000KPa条件下,反应4h,对MPC合成实验进行了验证。反应完成液先经简单蒸馏然后利用精馏分离,釜液冷却至室温得到白色晶体。对白色晶体利用熔点测定法,气质联用仪和气相色谱法进行定性、定量分析,确定白色晶体为MPC,其纯度为97.2%,收率为95.2%。用气相色谱法对反应完成液进行全物质分析,确定了其中各物质的质量百分含量为:CO₂0.1%、甲醇5.8%、DMC66.7%、苯胺（AN）0.3%、N-甲基苯胺（NMA）0.4%、MPC26.5%、二苯基脲（DPU）0.2%。2.依据实验数据利用通用流程模拟软件对10万吨/年MPC工艺流程进行了模拟。首先选择化学计量反应器建立了反应模块,然后确定了分离目标,根据各物质的性质利用探试合成法确定了分离方案:利用闪蒸罐分离出大部分的CO₂,将含量最多的DMC分离循环回反应釜,苯胺和N-甲基苯胺先作为一种物质与MPC分离后再进一步分离,苯胺循环回反应釜,由此确定了分离工艺,建立了初步工艺流程。对MPC和二苯基脲进行物性估算,然后选择Wilson-RK方程,完成初步工艺流程的模拟。对CO₂和甲醇的分离进行了两种方案的探讨,利用灵敏度分析确定了用精馏塔分离二者混合物的最终分离方案。利用塔底物流预热进料,确定了最终工艺流程,并将最终流程模拟结果与初步流程结果进行比较,结果表明最终流程所需热负荷减少1545.48kW,冷负荷增大953.44kW。MPC纯度和收率分别为99.99%和99.36%,甲醇纯度和收率分别为99.60%和99.30%,均达到了分离要求。3.对最终工艺流程的塔设备和换热器进行了设计。塔型选择板式塔,塔板类型选择F1型浮阀塔板,利用工程化学模拟系统（化工之星）进行了塔板的水力学设计,各塔塔径和塔板数为:DMC-AN分离塔塔径4.2m、塔板数20;甲醇-DMC分离塔塔径1.4m、塔板数35;NMA-MPC分离塔塔径2.0m、塔板数19;AN-NMA分离塔塔径0.6m、塔板数67;MPC-DPU分离塔塔径1.2m、塔板数30;CO₂-甲醇分离塔塔径0.4m、塔板数8。换热器型式选择管壳式,利用换热器模拟软件对各换热器进行设计,各换热器换热面积为:换热器1换热面积5.1m²,换热器2换热面积18.1m²,换热器3换热面积10.7m²,换热器4换热面积11.0m²,换热器5换热面积14.2m²,换热器6换热面积3.3m²。更多还原

【Abstract】 Methyl phenyl carbamate （MPC） is the important intermediate in non-phosgene synthesis of diphenylmethane diisocyanate. Recently technics using dimethyl carbonate and aniline to synthesis methyl phenyl carbamate is frequently studied.The technics which has high atom utilization ratio is environmentally friendly and will have good development prospect.1. Using dimethyl carbonate and aniline as reactants and anhydrous zinc acetate as catalyst, verification experiment of synthesis MPC was made in a high pressure reactor, reaction conditions were as follows: temperature 170℃, pressure 1000KPa, time 4h. Using simple distillation and rectifying column to separate the reacted solution and after cooling to room temperature white crystal was obtained. Qualitative analysis and quantitative analysis of crystal was made using melting point detection method, GC-MS machine and gas chromatographic method. The crystal was MPC, its mass fraction was 97.2% and yield coefficient was 95.2%. Reacted solution was analyzed by gas chromatographic method and each substance’s mass fraction was as follows:0.1% CO₂, 5.8% methanol, 66.7% DMC, 0.3% aniline （AN）, 0.4% N-methylaniline （NMA）, MPC 26.5%, 0.2% diphenylurea （DPU）.2. According to experimental data, using general process simulation software 100000 ton MPC per year was simulated. First, RStoic was selected, then seperation target was confirmed, based on chemical substances’s property seperation scheme was obtained by heuristic and synthesis approach: first, most CO₂ was seperated using a flash tank and then DMC which has the highest mass fraction was seperated and recirculated to the reactor; aniline and N-methylaniline was regarded as one material to separate from MPC and then they were made further seperation and aniline was recirculated to the reactor.After that seperation technics was obtained and initial flowsheet was completed. Property of diphenylurea and MPC was estimated, then Wilson-RK property method was selected and initial simulition was completed. Two seperation schemes of CO₂ and methanol were discussed; using rectification column to separate them was confirmed by sensitivity analysis. Finally, using tower bottom products preheated feed streams and then final flowsheet was made and simulated results of initial and final flowsheet were compared, result showed that heat load required of final flowsheet decreased 1545.48kW, cold load required increased 953.44kW. Mass fraction and yield coefficient of MPC was 99.99% and 99.36%, mass fraction and yield coefficient of methanol was 99.60% and 99.30%,these entire hit the target.3. Towers and heat exchangers in the final flowsheet were designed. Plate tower and F1 float valve were selected, then hydraulics of plate was designed by Engineering Chemical Simulation System （ECSS）, tower diameters and stage numbers were as follows: tower diameter of DMC and AN separating column was 4.2m, its stage number was 20, tower diameter of separating column of methanol and DMC was 1.4m, its stage number was 35, tower diameter of separating column of NMA and MPC was 2.0m, its stage number was 19, tower diameter of separating column of AN and NMA was 0.6m, its stage number was 67, tower diameter of separating column of MPC and DPU was 1.2m, its stage number was 30, tower diameter of separating column of CO₂ and methanol was 0.4m, its stage number was 8. Shell and tube heat exchanger was selected and its physical dimension was obtained by heat exchanger simulation software, heat interchanging area of each heat exchanger was as follows: heat interchanging area of heat exchanger 1 was 5.1m², heat interchanging area of heat exchanger 2 was 18.1m², heat interchanging area of heat exchanger 3 was 10.7m², heat interchanging area of heat exchanger 4 was 11.0m², heat interchanging area of heat exchanger 5 was 14.2m², heat interchanging area of heat exchanger 6 was 3.3 m2.更多还原