A scale-shift approach is introduced to further refine the pseudo-binary-mixture (PBM) simultaneous correction procedure for the solution of multicomponent, multistage separation problems [Ishii, Y., & Otto, F. D. (2001). An efficient simultaneous correction procedure for multicomponent, multistage separation calculations for non-ideal systems. Computers and Chemical Engineering, 25, 1285–1298; & Ishii, Y., & Otto, F. D. (2003a). A method to extend the domain of convergence for difficult multicomponent, multistage separation problems. Computers and Chemical Engineering, 27, 855–868]. The scale-shift approach takes advantage of the fact that a solution to a stage-wise separation problem is more easily obtained the fewer the number of stages. In the approach the column specified in a given problem is initially downsized to a configuration having a small number of stages and then scaled up to the original one in a multiple-step manner. A solution is obtained at each scale-shift step and the results are used as a set of initial assumptions to solve the subsequent scaled-up problem. Combining the scale-shift approach along with the gradual non-ideal enhancing method with the PBM algorithm provides a more robust and efficient algorithm for the simulation and solution of difficult multicomponent, multistage separation problems including those involving non-ideal mixtures that are highly sensitive to the quality of initial values. A geometric consideration for the gradual non-ideal enhancing method and details of the unique procedure for the algebraic inversion of matrices employed in the algorithm are also presented. 相似文献
In this study, a combined system of electrocoagulation (EC) and magnetic separation (MS) has been applied to the treatment
of dye wastewater, and its performance has been evaluated. The floes formed in the electrocoagulation using Fe anode are magnetized
and thus they could be removed by magnetic separation. The removal of suspended solids, color and COD was improved with an
increase in electric current up to about 15 A and with a decrease in liquid velocities in EC. While the remaining suspended
solids in the treated water were reduced to a few ppm and the color was removed almost perfectly (Max. 96%), that of COD was
relatively low and only 81%. A further powerful operation can be expected from the present system if it is combined with an
additional process, such as electrolysis or oxidation, to reduce COD more efficiently. 相似文献
The separation of light hydrocarbon mixtures (C1-C3) generated from petrochemical industry is vital and challenging process for obtaining valuable pure chemical feedstocks. In comparison to the energy intensive conventional separation technologies (cryogenic distillation, absorption and hydrogenation), the adsorptive separation is considered as a low energy cost and high efficiency process. Porous carbons have been demonstrated as excellent adsorbents for the separation of light hydrocarbons, owing to their designable structure and tailorable properties. This review summarizes the recent advances of using porous carbons as adsorbents for the separation of light hydrocarbons, including methane/nitrogen, methane/alkane, methane/carbon dioxide, ethylene/ethane and propylene/propane. We discuss the separation mechanisms and highlight the material features including pore structure, surface chemistry and target molecular properties that determine the separation performance. Furthermore, the challenges and development direction associated with carbonaceous adsorbents for light hydrocarbon separation are discussed, meanwhile the guidelines for the design of porous carbons are proposed. 相似文献
Membrane separation technology has popularized rapidly and attracts much interest in gas industry as a promising sort of newly chemical separation unit operation. In this paper, recent advances on membrane processes for CO2 separation are reviewed. The researches indicate that the optimization of operating process designs could improve the separation performance, reduce the energy consumption and decrease the cost of membrane separation systems. With the improvement of membrane materials recently, membrane processes are beginning to be competitive enough for CO2 separation, especially for post-combustion CO2 capture, biogas upgrading and natural gas carbon dioxide removal, compared with the traditional separation methods. We summarize the needs and most promising research directions for membrane processes for CO2 separation in current and future membrane applications. As the time goes by, novel membrane materials developed according to the requirement proposed by process optimization with increased selectivity and/or permeance will accelerate the industrialization of membrane process in the near future. Based on the data collected in a pilot scale test, more effort could be made on the optimization of membrane separation processes. This work would open up a new horizon for CO2 separation/Capture on Carbon Capture Utilization and Storage (CCUS). 相似文献
This paper presents a novel synthesis method for designing integrated processes for oil-in-water (O/W) emulsions treatment. General superstructure involving alternative separation technologies is developed and modelled as a mixed integer linear programming (MILP) model for maximum annual profit. Separation processes in the superstructure are divided into three main sections of which the pretreatment and final treatment are limited to the selection of one alternative (or bypass) only, while within the intermediate section various combinations of different technologies in series can be selected. Integrated processes composed of selected separation techniques for given ranges of input chemical oxygen demand (COD) can be proposed by applying parametric analyses within the superstructure approach. This approach has been applied to an existing industrial case study for deriving optimal combinations of technologies for treating diverse oil-inwater emulsions within the range of input COD values between 1000 mg?L?1 and 145000 mg?L?1. The optimal solution represents a flexible and profitable process for reducing the COD values below maximal allowable limits for discharging effluent into surface water.
