Investigation of energy-efficient heat pump assisted heterogeneous azeotropic distillation for separating of acetonitrile/ethyl acetate/n-hexane mixture

The conventional distillation is hard to accomplish the separation of acetonitrile/ethyl acetate/n-hexane mixture. Herein, a heterogeneous azeotropic distillation(HAD) without adding entrainer is proposed to separate ternary mixture. The proposed scheme is optimized via the simulated annealing algorithm and minimum total annual cost(TAC) is used as objective functions. To minimize energy consumption,heat pump is added on the basis of optimal heterogeneous azeotropic distillation and heat integration technology is used to further improve the energy recovery. The TAC, gas emission, energy consumption and exergy destruction are used to discuss the economy and environmental protection of processes.Among all the processes, the heat pump with higher preheating temperature(HPT) assisted HAD process by combining with heat integration(HAD-HPT-HI) has best performances on economic, environment,energy and exergy. Compared with conventional HAD process, the HAD-HPT-HI achieves the reductions of 52.17%, 68.86%, 65.87% and 65.46% on TAC, total energy consumption, gas emissions and exergy destruction, respectively.

Synthesis of γ-Al2O3 with High Surface Area and Large Pore Volume by Reverse Precipitation- azeotropic Distillation Method

γ-Al2O3 with high surface area and large pore volume combined with high thermal stability was synthe- sized by a reverse precipitation-azeotropic distillation method. The effects of azeotropic distillation on the characte- ristics of γ-Al2O3 were studied by means of X-ray diffraction（XRD）, Fourier transform infrared（FTIR） spectroscopy, transmission electron microscopy（TEM） and N2 adsorption-desorption. The results show that γ-Al2O3 dried by azeo- tropic distillation has excellent structure characteristics with a high surface area of 426 m2/g and a large pore volume of 2.56 cm3/g. After calcination at 1100 ℃, the surface area of γ-Al2O3 was still 92 mE/g with a large pore volume of 1.00 cma/g, indicating the potential application in catalyst and petroleum industry.

SEPARATION OF FORMIC ACID-WATER AZEOTROPIC MIXTURES BY MEMBRANE DISTILLATION

The azeotrope disappeared when the formic acid-water mixtures were treated by membrane distillation. Membrane distillation were used for separation of formic acid-water azeotropic mixtures for the first time.

Preparation of Liquor Flavoring from Yellow Water Based on Water Absorbent Resin

[Objective] This study was conducted to extract the scarce natural liquor flavorings desired by many liquor factories from yellow water. [Method] Strong water absorbent resin was used to absorb moisture from the yellow water in order to concentrate it into dense yellow water at first, followed by azcotropic dis- tillation of the previously concentrated yellow water, and then, catalytic esterification was performed to the remaining liquid after the distillation. [ Results] The 7. 066 7 fractions of concentrated yellow water with 56.7% ethanol could be obtained after the treatment of 100 fractions of yellow water with strong water absorbent resin. Azeotrope of 0.432 8 fraction of natural acetaldehyde, 0. 269 4 fraction of ethyl formate and methyl alcohol, 0. 975 0 fraction of ethyl acetate and methyl alco- hol could be obtained after the azeotropic distillation per 100 fractions of concentrated yellow water. After the addition of CaC12, O. 220 7 fraction of ethyl formate and 0. 514 2 fraction of ethyl acetate could be obtained after distillation of the azeotrope. Finally, 92. 094 8 fractions of esterification liquid with 38 kinds of flavor- ing compound could be obtained after catalytic esterification of 100 fractions of concentrated yellow water, and the content of ethyl acetate, ethyl propionate, ethyl- butyrate, ethyl valerate, ethyl lactate and ethyl bexanoate were as much as 142.9, 22.2, 54.2, 3.3,75.4 and 158.9 g/L, respectively. [ Conclusion] Top-grade Luzhou-flavor liquor could be made by mixing 6.5 fractions of common liquor with acetaldehyde, ethyl formate, ethyl acetate and esterification liquid which were ob- tained from 1 fraction of yellow water. Therefore, the yellow water has a great recycling value, and it tells us that the technique of extracting liquor flavorings from yellow water has tremendous market value.

Evolutionary Algorithms for Controller Tuning of Tert-Amyl-Methyl-Ether Reactive Distillation

Efficient tuning of the coefficients used by proportional-integral-derivative(PID)controllers enhances their performance.For highly non-linear systems,optimization algorithms are required to make the PID controllers more responsive to disturbances.The production of tert-amyl-methyl-ether(TAME),an essential additive for gasoline,in reactive distillation columns integrates highly non-linear reaction and separation processes.On the other hand,TAME distillation is an azeotrope distillation process,therefore non-linearity of this process is more complex than that of conventional distillation.PID-controller tuning methods applying a genetic algorithm(GA)and a particle swarm optimization(PSO)algorithm are compared using a dynamic simulation that integrates the optimization algorithms with the HYSYS process simulator.The PID controller response trends are analyzed following the introduction of a significant disturbance to the TAME reactive distillation column(i.e.,a ten percent change in the methanol feed temperature).The PSO PID controller tuning method that minimizes the integral of the absolute error(IAE)as its objective function significantly outperforms the GA tuning method.The novel PID-tuning methodology developed has more extensive application potential.