In this paper, we developed a novel process integrating vacuum distillation with atmospheric chlorination reaction(VD-ACR) to realize the flexible production of tetrachloroethane(TeCA) and pentachloroethane(PCA)from 1,2-dichloroethane(DCA). During the simulation, the distillation column and reactors were operated for separation and chlorination respectively under variable pressures and temperatures. It is interesting to note that VD-ACR processes producing pure TeCA or PCA can exhibit the similar configuration parameters after optimization, which enables the flexible production of TeCA and PCA with different molar ratios via changing operating parameters. The molar ratio of TeC A/PCA can be fine-tuned within the range of 0.9:0.1-0.1:0.9 through adjusting the amount of chlorine pumped into side reactors, giving rise to the increase of the heat duty of reboiler by five times. A pilot-scale experiment was then operated based-upon this VD-ACR process and the result matched well with the simulation. Therefore, the VD-ACR model presented in this study will be beneficial for the industrial-scale flexible production of TeCA and PCA from DCA.
Xian ChenYunpeng LiGe XuJihai TangZhuxiu ZhangMing ChenZhaoyang FeiMifen CuiXu Qiao
A reaction coupling system of transesteri fication and methoxycarbonylation with methyl phenyl carbonate(MPC) as intermediate was established to ef ficiently prepare 1,6-hexamethylene diurethane(HDU) from 1,6-hexamethylene diamine(HDA). The feasibility of the system was explored using the thermodynamics analysis,the reaction mechanism and the experiment results. The optimal reaction was carried out to get higher HDU yield. The thermodynamic analysis showed that the methoxycarbonylation of HDA with MPC, the Gibbs free energy of which was negative, was a spontaneous process. Furthermore, the equilibrium constant of the methoxycarbonylation of HDA with MPC was much greater than that of the transesteri fication of dimethyl carbonate(DMC) with phenol, so the reaction coupling could be realized under mild conditions. The reaction mechanism analysis indicated that phenoxy anion was the key species for reaction coupling. Higher MPC concentration was detected when sodium phenoxide was used as transesteri fication reactant with DMC, since the phenoxy anion of sodium phenoxide could be dissociated more easily. Sodium phenoxide was more suitable to prepare HDU through reaction coupling. A yield of HDU as high as 98.3% could be reached under the optimal conditions of m Ph ONa/m DMC= 0.027 and n DMC/n HDA= 8/1 at 90 °C in 2 h.
以磺酸改性的SBA-15(SO_3H-SBA-15)为催化剂,丙烯酸与莰烯为原料加成反应制备丙烯酸异冰片酯(IBOA)。在转速600 r/min下消除外扩散的影响,并采集反应动力学数据。将SO3H-SBA-15催化莰烯异构化副反应生成的α-松油烯、柠檬烯、葑烯归类为异构烯烃,与丙烯酸加成生成的相应丙烯酸酯归类为丙烯酸异构酯,采用拟一级动力学模型进行数据回归,得到丙烯酸与莰烯加成酯化、烯烃异构以及异构烯烃酯化反应的反应热分别为-9.41、-31.32和-13.39 k J/mol,动力学拟合结果与实验数据吻合良好,并且通过统计检验,表明动力学模型是可靠的。
The distillation column with side reactors (SRC) can overcome the temperature/pressure mismatch in the traditional reactive distillation, the column operates at temperature/pressure favorable for vapor-liquid separation, while the reactors operate at temperatures/pressures favorable for reaction kinetics. According to the smooth operation and automatic control problem of the distillation column with side reactors (SRC), the design, simulation calculation and dynamic control of the SCR process for chlorobenzene production are discussed in the paper. Firstly, the mechanism models, the integrated structure optimal design and process simulation systems are established, respectively. And then multivariable control schemes are designed, the controllability of SRC process based on the optimal steady-state integrated structure is explored. The dynamic response performances of closed-loop system against several disturbances are discussed to verify the effectiveness of control schemes for the SRC process. The simulating results show that the control structure using conventional control strategies can effectively overcome feeding disturbances in a specific range.
基于中间再沸器的热泵精馏是常规热泵的新拓展,可以推广应用于大温差精馏体系。将该技术应用于氯化苄的侧反应器/精馏塔耦合工艺,建立了其基于中间再沸器的热泵精馏新流程。采用理想热力学模型计算相平衡,等熵压缩模型模拟压缩机,运用数值处理软件Matlab,基于Newton-Raphson法对氯化苄的热泵精馏工艺进行了模拟计算,考察了关键参数对精馏过程能耗的影响,得出了适宜的工艺操作条件。结果表明:当中间再沸器安装于第7与第8块塔板间,最小传热温差为10 K,换热量为90 k W时,过程能耗较低。在工艺主体结构与分离任务相同的情况下,与基础工艺相比,热泵精馏工艺可节约年操作费用31.0%,年度总费用17.0%。
