A double-effect reactive distillation(DERD)process was proposed for the production of propylene glycol methyl ether from propylene oxide and methanol to overcome the shortcoming of low selectivity and high-energy cons...A double-effect reactive distillation(DERD)process was proposed for the production of propylene glycol methyl ether from propylene oxide and methanol to overcome the shortcoming of low selectivity and high-energy consumption in the tubular plug-flow reactor.A single-column reactive distillation(RD)process was conducted under optimized operating conditions based on sensitivity analysis as a reference.The results demonstrated that the proposed DERD process is able to achieve more than 95%selectivity of the desired product.After that,a design approach of the DERD process with an objective of the minimum operating cost was proposed to achieve further energy savings in the RD process.The proposed DERD configuration can provide a large energy-savings by totally utilization of the overhead vapor steam in the high-pressure RD column.A comparison of the single-column RD process revealed that the proposed DERD process can reduce the operating cost and the total annual cost of 25.3%and 30.7%,respectively,even though the total capital cost of DERD process is larger than that of the RD process.展开更多
A new dynamic non-equilibrium mixing-pool model for simulating start-up and dynamic re-sponse of a distillation column is reported.The proposed model is established on the basis ofconsidering the two dimensional flow/...A new dynamic non-equilibrium mixing-pool model for simulating start-up and dynamic re-sponse of a distillation column is reported.The proposed model is established on the basis ofconsidering the two dimensional flow/mixing behavior of actual trays in a distillation column.Com-parison is made among the computed results of the start-up time and the dynamic response time bythe proposed and five other typical models.It is found that the computed time for both dynamicprocesses is longer by the model which considers any flow/mixing pattern than by the model withoutsuch concern.The inertia effect of flow/mixing seems to be important and can not be ignored inmodeling the transient process of distillation.The proposed model,which is believed to be suitableto large column,seems somewhat useful in predicting industrial distillation dynamics.展开更多
In this paper,a generalized model of the reactive distillation processes was developed via rate-based approach. The homotopy-continuation method was employed to solve the complicated nonlinear model equations efficien...In this paper,a generalized model of the reactive distillation processes was developed via rate-based approach. The homotopy-continuation method was employed to solve the complicated nonlinear model equations efficiently. The simulation on the reactive distillation processes was carried out with the profiles of stage temperature,composition and flow rate for both vapor and liquid phases obtained. Based on careful analysis of the simulation results, the pitfalls in experimental design were detected. Finally, a software package for the simulation of reactive distillation processes was developed.展开更多
In this work, a procedure to simulate the MD (molecular distillation) process for lactic acid purification was developed. The simulation was carried out with the aid of the Aspen Plus Process Simulator. Flash vessel...In this work, a procedure to simulate the MD (molecular distillation) process for lactic acid purification was developed. The simulation was carried out with the aid of the Aspen Plus Process Simulator. Flash vessel was used to represent the MD process since the software does not present this unit operation. The simulation results with efficiency factors were in agreement with previously reported experimental data.展开更多
A systematic approach for the steady-state operation analysis of chemical processes is pro-posed.The method affords the possibility of taking operation resilience into consideration during thestage of process design.I...A systematic approach for the steady-state operation analysis of chemical processes is pro-posed.The method affords the possibility of taking operation resilience into consideration during thestage of process design.It may serve the designer as an efficient means for the initial screening ofalternative design schemes.An ideal heat integrated distillation column(HIDiC),without any reboileror condenser attached,is studied throughout this work.It has been found that among the various va-riables concerned with the ideal HIDiC,feed thermal condition appears to be the only factor exertingsignificant influences on the interaction between the top and the bottom control loops.Maximuminteraction is expected when the feed thermal condition approaches 0.5.Total number of stages andheat transfer rate are essential to the system ability of disturbance rejection.Therefore,more stagesand higher heat transfer rate ought to be preferred.But,too many stages and higher heat transfer ratemay increase the load of the展开更多
The simulated process model of the HAc dehydration process under actual overloaded condition was conducted by amending the model of standard condition in our previous work using the process data collected from actual ...The simulated process model of the HAc dehydration process under actual overloaded condition was conducted by amending the model of standard condition in our previous work using the process data collected from actual production. Based on the actual process model, the operation optimization analysis of each plant(HAc dehydration column, decanter and NPA recycle column) was conducted using Residue Curve Maps(RCMs),sensitivity analysis and software optimization module. Based on the optimized parameters, the influence of feed impurity MA and the temperature of decanter on the separating effect and energy consumption of the whole process were analyzed. Then the whole process operation optimizing strategy was proposed with the objective that the total reboiler duty Q Total of C-1 and C-3 reaches the minimum value, keeping C-1 and C-3 at their optimized separation parameters obtained above, connecting all the broken recycle and connection streams, and using the temperature of D-1 as operation variable. The optimization result shows that the total reboiler duty Q Total of the whole process can reach the minimum value of 128.32 × 10~6 k J·h^(-1) when the temperature of decanter is 352.35 K, and it can save 5.94 × 10~6 k J·h^(-1), about 2.56 t·h^(-1) low-pressure saturated vapor.展开更多
The trichlorosilane(TCS)purification process consumes a significant amount of energy to achieve the high purity requirement for TCS quality(99.9999%).This work proposed a series of energy saving technology to enhance ...The trichlorosilane(TCS)purification process consumes a significant amount of energy to achieve the high purity requirement for TCS quality(99.9999%).This work proposed a series of energy saving technology to enhance the TCS purification process,including the conventional process,the conventional process coupled with heat-pump(HP),the multi-effect distillation process,and the dividing-wall columns process.All proposed schemes have been conceptually constructed by Aspen Plus.The design and optimization of the processes have been performed by the sensitivity analysis and the response surface methodology.Moreover,the energy consumption and total annual cost(TAC)for these schemes were discussed.The simulation results show that the TAC of the conventional process coupled with the integrated heat pump can reduce 50.5%of energy consumption as compared with the conventional process;the double-effect and three-effect processes can save 15.6%and 33.8%of energy consumption,respectively;the dividing wall column process and that coupled with the heat pump process can reduce by 22.3%and 48.1%of energy consumption,respectively.It can be found that the operating cost can be saved by using the heat pump technology,while the capital cost increases due to the investment in the compressor,when the processes coupled with the heat pump are used.These results demonstrate that the conventional process coupled with the HP technology has advantages over other distillation schemes for TCS purification in terms of the energy saving and economic effects.展开更多
In this work, the process simulation of pressure-swing distillation(PSD) and extractive distillation(ED) using ionic liquid(IL) 1-butyl-3-methylimidazolium acetate([bmim][OAc]) as the entrainer for separation of ethyl...In this work, the process simulation of pressure-swing distillation(PSD) and extractive distillation(ED) using ionic liquid(IL) 1-butyl-3-methylimidazolium acetate([bmim][OAc]) as the entrainer for separation of ethyl acetateethanol-water mixture is performed. The design parameters of the two distillation processes are optimized with the minimum total annual cost(TAC) serving as the objective function. The results show that the TAC saving of ED process is 35.27% in comparison with that of PSD process in the case of achieving the same purity and yield of ethyl acetate.In addition, the dynamic controllability of ED process is further studied. The traditional two-point temperature control structure is proposed for the ED process, and it works pretty well while taking into account the disturbances in both feed rate and feed composition.展开更多
This paper focuses on the dynamic control of distillation column with side reactors(SRC) for methyl acetate production. To obtain the optimum integrated structure and steady state simulation, the systematic design app...This paper focuses on the dynamic control of distillation column with side reactors(SRC) for methyl acetate production. To obtain the optimum integrated structure and steady state simulation, the systematic design approach based on the concept of independent reaction amount is applied to the process of SRC for methyl acetate production. In addition to the basic control loops, multi-variable model predictive control modular with methyl acetate concentration and temperature of sensitive plate is designed. Then, based on process simulation software Aspen Plus, dynamic simulation of SRC for methyl acetate production is used to verify the effectiveness of the control scheme.展开更多
The operation of an ideal heat integrated distillation column (HIDiC) is addressed. Five kinds of control configurations, i.e. single-loop control, multi-loop control, multivariable internal model control (IMC), modif...The operation of an ideal heat integrated distillation column (HIDiC) is addressed. Five kinds of control configurations, i.e. single-loop control, multi-loop control, multivariable internal model control (IMC), modified multivariable internal model control (MIMC) and nonlinear process model-based control (NPMC), are designed and applied to the process. Simulation results demonstrate that all of the above control configurations are valid for product quality control. NPMC control configuration is found to be the best one among all the alternatives. It can readily realize setpoint transitions and conduct effectively against external disturbances. MIMC control configuration ranks second in the row for its regulatory responses to feed composition disturbances with relatively extended setting time. Next comes from the multi-loop control configuration, which is more or less handicapped by its greater deviations and overshootings. IMC control configuration can not compete with the multi-loop control configuration because it is extremely sensitive to operating condition changes. Single-loop control configuration is the worst one among all the mentioned control configurations. Its responses for the uncontrolled end products are extremely sluggish.展开更多
A generalized steady-state model is being developed for an internal heat integrated distillation column (IHIDiC). A procedure incorporating the Newton-Raphson method is devised for solving the model equations. Separat...A generalized steady-state model is being developed for an internal heat integrated distillation column (IHIDiC). A procedure incorporating the Newton-Raphson method is devised for solving the model equations. Separation of an ethanol-water binary mixture is simulated and analyzed with the model. Two pinch points are found within the process, making the separation extremely difficult and expensive. Two sharp fronts in the temperature and the composition profiles are being observed. With the introduction of heat integration, satisfactory separation may be obtained in a limited number of stages with lower reflux ratios. Increasing the pressure difference between the rectifying and the stripping sections, however, would bring about a reduced relative volatility between the two components involved, creating adverse separation performances. It is obvious that optimization of the IHIDiC is of prime importance.展开更多
基金supported by the National Nature Science Foundation of China(21878315 and 21808223)National Key Research and Development Program of China(2017YFA0206803)+3 种基金Innovation Academy for Green ManufactureCAS(IAGM2020C17)K.C.Wong Education Foundation(GJTD-2018-04)。
文摘A double-effect reactive distillation(DERD)process was proposed for the production of propylene glycol methyl ether from propylene oxide and methanol to overcome the shortcoming of low selectivity and high-energy consumption in the tubular plug-flow reactor.A single-column reactive distillation(RD)process was conducted under optimized operating conditions based on sensitivity analysis as a reference.The results demonstrated that the proposed DERD process is able to achieve more than 95%selectivity of the desired product.After that,a design approach of the DERD process with an objective of the minimum operating cost was proposed to achieve further energy savings in the RD process.The proposed DERD configuration can provide a large energy-savings by totally utilization of the overhead vapor steam in the high-pressure RD column.A comparison of the single-column RD process revealed that the proposed DERD process can reduce the operating cost and the total annual cost of 25.3%and 30.7%,respectively,even though the total capital cost of DERD process is larger than that of the RD process.
文摘A new dynamic non-equilibrium mixing-pool model for simulating start-up and dynamic re-sponse of a distillation column is reported.The proposed model is established on the basis ofconsidering the two dimensional flow/mixing behavior of actual trays in a distillation column.Com-parison is made among the computed results of the start-up time and the dynamic response time bythe proposed and five other typical models.It is found that the computed time for both dynamicprocesses is longer by the model which considers any flow/mixing pattern than by the model withoutsuch concern.The inertia effect of flow/mixing seems to be important and can not be ignored inmodeling the transient process of distillation.The proposed model,which is believed to be suitableto large column,seems somewhat useful in predicting industrial distillation dynamics.
基金Supported by the State Key Project of the National Natural Science Foundation of China (No.2929054)
文摘In this paper,a generalized model of the reactive distillation processes was developed via rate-based approach. The homotopy-continuation method was employed to solve the complicated nonlinear model equations efficiently. The simulation on the reactive distillation processes was carried out with the profiles of stage temperature,composition and flow rate for both vapor and liquid phases obtained. Based on careful analysis of the simulation results, the pitfalls in experimental design were detected. Finally, a software package for the simulation of reactive distillation processes was developed.
文摘In this work, a procedure to simulate the MD (molecular distillation) process for lactic acid purification was developed. The simulation was carried out with the aid of the Aspen Plus Process Simulator. Flash vessel was used to represent the MD process since the software does not present this unit operation. The simulation results with efficiency factors were in agreement with previously reported experimental data.
文摘A systematic approach for the steady-state operation analysis of chemical processes is pro-posed.The method affords the possibility of taking operation resilience into consideration during thestage of process design.It may serve the designer as an efficient means for the initial screening ofalternative design schemes.An ideal heat integrated distillation column(HIDiC),without any reboileror condenser attached,is studied throughout this work.It has been found that among the various va-riables concerned with the ideal HIDiC,feed thermal condition appears to be the only factor exertingsignificant influences on the interaction between the top and the bottom control loops.Maximuminteraction is expected when the feed thermal condition approaches 0.5.Total number of stages andheat transfer rate are essential to the system ability of disturbance rejection.Therefore,more stagesand higher heat transfer rate ought to be preferred.But,too many stages and higher heat transfer ratemay increase the load of the
基金Supported by Shanghai University Youth Teacher Training Program(ZZsl15002)Shanghai Sailing Program(17YF1413100 and 17YF1428300)
文摘The simulated process model of the HAc dehydration process under actual overloaded condition was conducted by amending the model of standard condition in our previous work using the process data collected from actual production. Based on the actual process model, the operation optimization analysis of each plant(HAc dehydration column, decanter and NPA recycle column) was conducted using Residue Curve Maps(RCMs),sensitivity analysis and software optimization module. Based on the optimized parameters, the influence of feed impurity MA and the temperature of decanter on the separating effect and energy consumption of the whole process were analyzed. Then the whole process operation optimizing strategy was proposed with the objective that the total reboiler duty Q Total of C-1 and C-3 reaches the minimum value, keeping C-1 and C-3 at their optimized separation parameters obtained above, connecting all the broken recycle and connection streams, and using the temperature of D-1 as operation variable. The optimization result shows that the total reboiler duty Q Total of the whole process can reach the minimum value of 128.32 × 10~6 k J·h^(-1) when the temperature of decanter is 352.35 K, and it can save 5.94 × 10~6 k J·h^(-1), about 2.56 t·h^(-1) low-pressure saturated vapor.
基金financial support from the National Natural Science Foundation of China (project No. 21406157)
文摘The trichlorosilane(TCS)purification process consumes a significant amount of energy to achieve the high purity requirement for TCS quality(99.9999%).This work proposed a series of energy saving technology to enhance the TCS purification process,including the conventional process,the conventional process coupled with heat-pump(HP),the multi-effect distillation process,and the dividing-wall columns process.All proposed schemes have been conceptually constructed by Aspen Plus.The design and optimization of the processes have been performed by the sensitivity analysis and the response surface methodology.Moreover,the energy consumption and total annual cost(TAC)for these schemes were discussed.The simulation results show that the TAC of the conventional process coupled with the integrated heat pump can reduce 50.5%of energy consumption as compared with the conventional process;the double-effect and three-effect processes can save 15.6%and 33.8%of energy consumption,respectively;the dividing wall column process and that coupled with the heat pump process can reduce by 22.3%and 48.1%of energy consumption,respectively.It can be found that the operating cost can be saved by using the heat pump technology,while the capital cost increases due to the investment in the compressor,when the processes coupled with the heat pump are used.These results demonstrate that the conventional process coupled with the HP technology has advantages over other distillation schemes for TCS purification in terms of the energy saving and economic effects.
基金supported by the National Natural Science Foundation of China (Grant No. 21676299 and 21476261)
文摘In this work, the process simulation of pressure-swing distillation(PSD) and extractive distillation(ED) using ionic liquid(IL) 1-butyl-3-methylimidazolium acetate([bmim][OAc]) as the entrainer for separation of ethyl acetateethanol-water mixture is performed. The design parameters of the two distillation processes are optimized with the minimum total annual cost(TAC) serving as the objective function. The results show that the TAC saving of ED process is 35.27% in comparison with that of PSD process in the case of achieving the same purity and yield of ethyl acetate.In addition, the dynamic controllability of ED process is further studied. The traditional two-point temperature control structure is proposed for the ED process, and it works pretty well while taking into account the disturbances in both feed rate and feed composition.
基金Supported by the National Natural Science Foundation of China(61673205,61503181,21727818)National Key R&D Program of China(2017YFB0307304)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20141461,BK20140953)the State Key Laboratory of Materials-Oriented Chemical Engineering Open Subject(kl16-07)
文摘This paper focuses on the dynamic control of distillation column with side reactors(SRC) for methyl acetate production. To obtain the optimum integrated structure and steady state simulation, the systematic design approach based on the concept of independent reaction amount is applied to the process of SRC for methyl acetate production. In addition to the basic control loops, multi-variable model predictive control modular with methyl acetate concentration and temperature of sensitive plate is designed. Then, based on process simulation software Aspen Plus, dynamic simulation of SRC for methyl acetate production is used to verify the effectiveness of the control scheme.
文摘The operation of an ideal heat integrated distillation column (HIDiC) is addressed. Five kinds of control configurations, i.e. single-loop control, multi-loop control, multivariable internal model control (IMC), modified multivariable internal model control (MIMC) and nonlinear process model-based control (NPMC), are designed and applied to the process. Simulation results demonstrate that all of the above control configurations are valid for product quality control. NPMC control configuration is found to be the best one among all the alternatives. It can readily realize setpoint transitions and conduct effectively against external disturbances. MIMC control configuration ranks second in the row for its regulatory responses to feed composition disturbances with relatively extended setting time. Next comes from the multi-loop control configuration, which is more or less handicapped by its greater deviations and overshootings. IMC control configuration can not compete with the multi-loop control configuration because it is extremely sensitive to operating condition changes. Single-loop control configuration is the worst one among all the mentioned control configurations. Its responses for the uncontrolled end products are extremely sluggish.
文摘A generalized steady-state model is being developed for an internal heat integrated distillation column (IHIDiC). A procedure incorporating the Newton-Raphson method is devised for solving the model equations. Separation of an ethanol-water binary mixture is simulated and analyzed with the model. Two pinch points are found within the process, making the separation extremely difficult and expensive. Two sharp fronts in the temperature and the composition profiles are being observed. With the introduction of heat integration, satisfactory separation may be obtained in a limited number of stages with lower reflux ratios. Increasing the pressure difference between the rectifying and the stripping sections, however, would bring about a reduced relative volatility between the two components involved, creating adverse separation performances. It is obvious that optimization of the IHIDiC is of prime importance.