Inlet Feed Research Articles

A step towards enhancing the efficiency of biofilm mediated degradation of brilliant green dye in packed bed bioreactor: Statistical and toxicity analysis

This study aims to investigate the biodegradation of brilliant green (BG) dye in a packed bed bioreactor (PBBR) using Bacillus lichenifomis immobilized polyurethane (PU) foam as support material. The operating process parameters (e.g., pH, dye concentration, and inoculum dose) were optimized using response surface methodology (RSM) and artificial neural network (ANN). A sensitivity analysis reveals that pH has comparatively more significance (46 %) than the other parameters. Further, PBBR was continuously operated at various inlet feed flow rates (10–50 mL/h) under optimum conditions for 60 days. Maximum removal efficiency (RE) and elimination capacity (EC) were found to be 91.2 % and 88.0 mg/L.d, respectively. Monod and Andrews-Haldane models were applied for kinetic study and kinetics parameters μmax and Ks was found to be 0.125 per day and 38.9 mg/L for Monod and 0.175 per day and 45.1 mg/L for Andrew – Haldane model respectively. UV–vis and FTIR analysis confirmed the successful biodegradation of BG dye. Stress caused by BG dye was assessed by chlorophyll (a and b) and carotenoid content. Superoxide dismutase (SOD) activity was analyzed for biologically treated samples. Bacterial toxicity study reveals that biologically treated samples showed significantly less bioluminescence inhibition.

Experimental Results for a Novel Flash Evaporation and Phase Separation System for Desalination of Sea Water

Abstract A novel system combining dynamic flash evaporation and vapor separation for desalination has been investigated in this work. The feed water passes through injection tubes which are connected to injector passages installed tangentially onto a separator tube. Flashing in the injection tubes is initiated from pressure drop due to friction and acceleration resulting in a two-phase mixture. Centrifugal force from tangential injection separates the two-phase mixture. In this compact system, vapor production and phase separation occur on the order of several milliseconds. Tap water and seawater were used as inlet feed water for the system. Thermal conversion efficiency to analyze the vapor production efficacy and phase separation efficiency to evaluate the purity of the condensate were investigated to evaluate the system. Thermal conversion and phase separation efficiencies up to 98% were obtained with the single stage system. Further improvement in purity of condensate was achieved with a two-stage system. In the two-stage system, the vapor captured along with some entrained droplets from the first stage was directed to a second set of injector passages connected in series to the first stage retrieval tube. With a two-stage system and seawater with salt concentration by mass of 2.5%, collected condensate with salt concentrations lower than 0.02% by mass was achieved, which is comparable to that of potable water. Thus, the novel dynamic flash evaporation and vapor separation system have been demonstrated to be very effective in producing potable water.

Preparation, optimization and properties of FOX-7@Al microparticles via spray drying

ABSTRACT In this laboratory, FOX-7@Al composites were developed by spray-drying technique. The effects of inlet temperature, feed rate and nitrogen flow rate and their interactions on the morphology and yield of FOX-7@Al were investigated by response surface methodology (RSM). Corresponding empirical equations were derived to show these interactions. The optimum process conditions determined by RSM were as follows: inlet temperature of 90°C, nitrogen flow rate of 450 L·h−1 and feed rate of 4.25 mL·min−1. The crystal structure, surface element distribution and thermal decomposition performance of FOX-7@Al in optimal condition were researched. Small crystallinity and low crystallinity of FOX-7 were observed in the XRD pattern, which were caused by the recrystallization of FOX-7 during the spray drying process. FOX-7@Al exhibited a concentrated energy release efficiency and a uniformed component distribution. The surface of aluminum nanoparticle was covered by FOX-7 and Viton, which effectively suppressed the agglomeration of aluminum nanoparticles and enhanced the heat and mass transfer properties. The work present here not only gives information for predicting, optimizing and improving the preparation conditions of energetic composites, but also provides a spray drying method for dealing with the materials distribution and thermal decomposition performance of composite aluminized explosives.

Hybrid multi-stage flash (MSF) and membrane distillation (MD) desalination system for energy saving and brine minimization

A hybrid multi-stage flash and multi-stage membrane distillation system for freshwater recovery from the rejected MSF brine is studied. The proposed system reduces environmental impact through reducing the rate of rejected brine, desalination energy and product cost. This is achieved by utilizing the energy rejected from the brine heater to heat a portion of MSF reject that is fed into the MD system since MD systems operate at relatively low temperature and are tolerant to high salinity input. The system includes a multi-stage MD system with a capacity ranging from 75 to 200 m3/day that help in reducing brine volume as model novelty. MD energy is supplied from the condensate leaving MSF brine heater. The effect of MD feed inlet temperature on the performance of stand-alone MD and hybrid MSF-MD systems is investigated for various layouts of the integrated system. Performance of the proposed system is quantified in terms of productivity, MD gained output ratio (GOR), specific electric energy consumption (SEEC), freshwater recovery rate (RR) and water cost. The hybrid MSF-MD system can be used for rejected brine reduction. Parallel feed – parallel coolant integrated arrangement provides the best performance among other configurations, with a productivity, RR, GOR, and SEEC of 218.3 m3/day, 3.544 %, 0.921 and 1.107 kWh/m3, respectively for the MD system. Additionally, the hybrid MSF-MD system yielded about 30,098m3/day, 57.544 %, and 8.583 in productivity, RR and GOR, respectively. MD freshwater cost is reduced by 70 % - 90 % compared to the conventional MD system with an independent energy supply.

Numerical Study on the performance of a heat pump-driven-DCMD for sustainable desalination

The study presents an energy-efficient desalination system that combines direct contact membrane distillation (DCMD) and a heat pump to improve thermal efficiency and integrate with photovoltaics. DCMD is a sort of thermal desalination process, and it requires a lot of thermal energy. A heat pump is a device that produces both hot and cold energy simultaneously with less electrical energy input compared to other heating devices, such as a boiler and an electrical heater. A hollow-fiber DCMD and a 10-kW water-to-water heat pump were considered for a numerical simulation in this study. Numerical models were established for each device and validated against the results obtained from the literature. The simulation was first carried out to identify the performance of the system based on the baseline. After that, a series of simulations were carried out in order to investigate the performance of the proposed system in terms of specific energy consumption (SEC), gained output ratio (GOR), and the coefficient of performance (COP) under various operating conditions. Results showed that the minimum SEC and the maximum GOR were achieved at the inlet feed water temperature of 66.5°C with a mass flow rate of 20 kg/min and the inlet permeate temperature of 19.8°C with a mass flow rate of 10 lpm. On the other hand, it was found that the maximum COP can be observed at the inlet feed water temperature of 23.6°C with a mass flow rate of 10 lpm and at the inlet permeate temperature of 8.9°C with a mass flow rate of 20 lpm.

The Effects of Spray Drying Conditions on Moisture Content, Water Activity, Bulk Density, and Tapped Density of Rice Milk Powder

Cow's milk is usually consumed by the majority of the population and is well thought of as a wholesome complete food providing major nutrients like fat, proteins, and carbohydrates. Though milk is considered to be a complete food yet limited availability or near absence of certain minerals such as iron, and vitamins restricts its recommendation as a complete food for infants older than 12 months. To meet this requirement the rice milk was prepared by using the broken rice. Spray drying is a method applied to dry a wide variety of food extracts. The resulting powders are conveniently stored, transported, and handled. To increase the shelf life of the rice milk, spray drying of the rice milk was done by using the different inlet temperatures and feed flow rates. An experiment was conducted to study the effects of spray drying conditions on moisture content, bulk density, and tapped density of rice milk powder in 2019 at Bapatla, Andhra Pradesh, India. The broken rice was used to prepare rice milk with the optimized process parameters. Temperature and feed flow rate were optimized with the desirability function which satisfied all the responses with the required values to obtain optimum conditions for spray drying. The predicted optimum conditions were T=138°C and Q=35 MLM-1. Under these conditions, the response values for bulk density, moisture content, and water activity were 0.51 GML-1, 3.8% and 0.30.

Investigation of feed flow effect using CFD-DSMC method in a gas centrifuge

In this study, the effect of rarefied region in the rotor of the centrifuge was investigated. In a rotor of the centrifuge, the feed inlet is positioned in the rarefied area. The continuum hypothesis is not valid in the rarefied area; therefore, it desires to be analyzed by probabilistic methods like Direct Simulation Monte Carlo (DSMC). In the present study, Computational Fluid Dynamic (CFD) method is used to simulate the continuum area, and the DSMC method is employed in the rarefied area. An implicit coupled density-based scheme was performed for CFD method, and Variable Hard Sphere (VHS) and diffuse model were employed in the DSMC method. Also, the local Knudsen number was defined to determine the interface location between the continuum-rarefied regions (r=0.086 m). The comparison results of pure CFD and CFD-DSMC methods illustrated large differences between the flow properties in the rarefied regions. The results showed that the value of separation power obtained from pure CFD and CFD-DSMC solution is 10.5% different.

Comprehensive experimental and theoretical studies on material-gap and water-gap membrane distillation using composite membranes

Experimental and theoretical studies on material-gap membrane distillation (MGMD) and water-gap membrane distillation (WGMD) are presented in this paper to demonstrate the effect of gaps filled with different materials on permeation flux. A flat-sheet composite membrane composed of an active polytetrafluoroethylene layer and a support polypropylene layer was employed in the experiments. Graphite, water, silica gel, and zeolite were used to measure the effects of these materials on permeation flux and thermal resistance. In the experiments and simulations, the size of the material and water gaps was kept constant at 5 mm. The graphite-filled MGMD permeation flux was approximately 11–22% higher than that of the WGMD at inlet feed temperatures in the range of 40–70 °C. However, the permeation flux of MGMD filled with silica gel and zeolite was 17–24% and 18–27% lower than that of WGMD, respectively. At thermal conductivities below 5 W/mK, the permeation flux of the MGMD with a material packing density of 40% was higher than that with a material packing density of 60%. The MGMD permeation flux with a material packing density of 60% was higher than that with a material packing density of 40% above a thermal conductivity of 5 W/mK. Furthermore, the MGMD permeation flux and overall thermal resistance were primarily controlled by the material gap, with materials having thermal conductivities below 30 and 20 W/mK for the bead- and pellet-type materials (i.e., packing densities of 40 and 60%), respectively.

A model of reactive settling of activated sludge: Comparison with experimental data

A non-negligible part of the biological reactions in the activated sludge process for treatment of wastewater takes place in secondary settling tanks (SST) that follow biological reactors. It is therefore of interest to develop models of so-called reactive settling that describe the spatial variability of reaction rates caused by the variation of local concentration of biomass due to hindered settling and compression. A reactive-settling model of an SST is described by a system of nonlinear partial differential equations and a numerical scheme is introduced for the simulation of hindered settling of flocculated particles, compression at high concentrations, dispersion of the flocculated particles in the suspension, dispersion of the dissolved substrates in the fluid, and the mixing that occurs near the feed inlet. The model is fitted to experiments from a pilot plant where the SST has a varying cross-sectional area. For the reactions, the Activated Sludge Model No. 1 (ASM1) is used with temperature-adjusted standard coefficients. The constitutive functions for hindered settling and compression are calibrated to a series of conventional batch settling experiments after the initial induction period of turbulence and reflocculation has been transformed away. The overall conclusion is thus that a careful treatment of batch-settling data to calibrate the sedimentation-compression model is sufficient to ensure good predictability of the reactive sedimentation process in a pilot SST, while the optional inclusion of hydrodynamic dispersion (modelled with two parameters) or a term modelling the mixing of the suspension near the feed inlet at most marginally improve predictability.

Microstructure and Crystallographic Texture in Twin-Roll Casting of AA1050 Aluminum Alloy: Simulation and Industrial Validation

Twin-roll casting (TRC) is a process in which liquid metal is introduced directly between counter-rotating water-cooled rolls, where it solidifies and is rolled to a strip having final thickness of 3 to 8 mm. TRC for aluminum is best suited to those alloys having a narrow freezing range with little susceptibility to hot tearing, such as 1XXX, 3XXX, 5XXX, and 8XXX. TRC offers advantages over conventional DC casting followed by hot and cold rolling for these alloys due to its lower capital cost, and decreased downstream processing operational cost and energy consumption, since hot rolling is not required. The microstructure formed in the strip must be carefully controlled, because as a near-net shape product used mostly for non-age-hardenable alloys, there is limited opportunity to modify it by subsequent processing. In particular, the near-surface microstructure has a strong effect on performance in forming applications. In this article, we present a computational model of TRC, and validate it for AA1050 aluminum alloy in a production environment. The novel aspect of this work is that the model is used to predict the final microstructure and crystallographic texture of the cast strip. The model is validated in plant trials for strip cast at a range of thicknesses, casting speeds, and caster setup by comparing the predicted microstructure, texture, and process outcomes such as roll separating force and forward slip to their corresponding measured values. We then apply the validated model to explore process parameters outside the standard practices, including feed inlet setback, casting speed, metal inlet temperature, and changing roll material to demonstrate how the microstructure and texture can be controlled via these parameters.

Process optimization for preparation of milk protein co‐precipitate using calcium lactate as coagulant

AbstractMilk protein co‐precipitates (MPCP) are rich in milk proteins but rejected globally owing to their poor solubility. The investigation was aimed to prepare MPCP with enhanced solubility via modification of their existing production method. MPCP was manufactured from pasteurized cow skim milk (PCSM) by spray‐drying calcium lactate‐induced co‐precipitate dispersion. The conditions for the preparation of coagulum (gel point‐Tg, holding time and coagulation time) and for efficient spray drying (pH of feed solution and inlet air temperature) were optimized. PCSM containing 0.5% calcium lactate incubated at 30°C/15 min and heated at 80°C/20 min, exhibited maximum protein recovery (92%) in the coagulum. The coagulum was diluted with distilled water (1:1.4, curd: water), and feed characteristics were optimized for spray drying. MPCP powders obtained from feed solution (adjusted to pH 6.7 with disodium hydrogen phosphate) spray‐dried at an inlet temperature of 160°C and outlet temperature (~60°C) demonstrated maximum solubility of 39.57% with a protein content of 78.99%.Novelty impact statementThis trial successfully achieved ~80% of protein content in MPCP with solubility of ~40% using a lower level (<0.132%) of calcium chelator (DSP). This enhances the potential of MPCP as an ingredient in various food formulations. MPCP can be a potential ingredient in bread and bakery industry as well as dairy industry in cheese formulations; high protein yoghurt formulations etc.

Preparation of Rice Bran Protein (RBP) Powder Using Spray Drying Method at the Optimal Condition and Its Protein Quality

Rice bran is a by-product of the rice milling process. It contains a high concentration of protein. Rice brans are frequently utilized as feed cattle, fertilizer, and fuel. However, their application as human nutrition supplements is uncommon, and the necessary process for this purpose is yet to be established, including the drying process. This study aims to evaluate the effect of the spray-drying parameters, the inlet temperature, inlet flowrate, and inlet air flowrate, on rice bran protein (RBP) powder and optimize it using response surface methodology (RSM). A thermal water-based extraction method was utilized prior to the drying process. The correlation between the spray-drying parameters, i.e., the inlet temperature (120 to 210 °C), feed flowrate (5 to 55%), and air flowrate (246 to 670 L/h), and the RBP yield were investigated. The quality of the RBP powder was evaluated based on acid amino profiling in the mixture through de novo peptide sequencing. The optimized operating conditions for the maximum yield of RBP powder (25.7 g RBP/100 g RRB) are 178 °C, feed flowrate of 25%, and air flowrate of 450 L/h. The main peptides that contribute to RBP powder protein are globulin and glutelin; meanwhile, prolamin is believed to degrade during the drying process. The process also produced protein sugar, helping to produce fine particles powder without the drying agent.

CFD-DEM Simulation of Particle Fluidization Behavior and Glycerol Gasification in a Supercritical Water Fluidized Bed

In this study, a mathematical model of hydrogen production from glycerol gasification in supercritical water was established based on the CFD-DEM method. The fluidization process of a supercritical water fluidized bed and the effects of bed height and feed structure on particle distribution and residence time of feedstock were analyzed. Additionally, the temperature field in the fluidized bed, the reaction rate distribution of each reaction and the influence of wall temperature on gas yields were also studied. The simulation results show that the bubble channel is easy to form along the wall at one side of the feed inlet. When the initial bed height is high, and the double symmetric feed inlet structure is used, the residence time of the feedstock is prolonged. The pyrolysis of glycerol mainly occurs in the middle and lower part of the fluidized bed reactor, and the reaction rate of the water gas shift reaction and methanation reaction are highest near the outlet, and a high wall temperature is conducive to the glycerol gasification.

Effects of spray-drying parameters on physicochemical properties of powdered fruits

This review features different powdered fruits with optimal storage stability and physiochemical parameters. Spray-drying parameters, such as temperatures and flow rate, can affect the physical properties of powders. Carrier agents provide powders with various favorable qualities, e.g. good flow rate. Commercial spray-drying of fruit juice knows different carrier agents. 
 The review involved scientific and methodological publications, conference papers, patents, regulatory papers, and Internet resources. They were subjected to grouping, categorization, comparative analysis, and consolidation. 
 Inlet temperature, maltodextrin concentration, and air flow rate of spray-drying increased the powder yield but decreased the moisture content. Inlet temperature, maltodextrin concentration, and feed flow rate affected the solubility. Effects of atomization rate, air flow rate and free flow rate were assessed in terms of yield, moisture content, hygroscopicity, and solubility. 
 The article introduces the fundamentals of spray-drying and describes the effect of each spray-drying parameter on the powder quality. The list of parameters included inlet air temperature, atomization rate, air flow, and feed flow rate. We also evaluated the impacts of various carrier agents on the powder quality. The article contributed to a better understanding of how variable parameters affect the quality of food powders. The results provide the food industry with better choice options to adopt certain parameters for specific production needs.

C4+ liquid recovery from natural gas by temperature swing adsorption followed by liquefaction of heavy extracted product

Recovery of natural gas liquid (NGL) was investigated by temperature swing adsorption (TSA) process. The process was designed with four columns of H-type silica gel adsorbent, working in a cyclic adsorption–desorption operation of natural gas at high pressure. The NG feed composition contained 89 % methane, 1.6% C4+ (butane and pentane), and other impurities such as CO2, with feed inlet weight hourly space velocity of 5.7 kgfeed/hr.kg,ads, at 85 bar pressure and 30 °C temperature. The cyclic operation was designed with three steps consisting of adsorption at high pressure, heating by purging with the hot NG at 270 °C and 25 % purge/feed ratio, followed by cooling with clean NG product from adsorption step, at the same pressure. Thereafter the regenerated heavy product from the heating step was liquified to gather C4+ product. Modeling and simulation of this process were carried out to simulate and optimize the operating conditions with the aim of maximizing recovery of the C4+ liquid product and minimizing outlet NG dew point. The required model parameters were evaluated by the experimental studies at the static and dynamic conditions and fitting to the proper isotherm and kinetic models, respectively. As the results of the process optimization, the fraction of C5 in the light NG product was reduced from 0.7 % to 0.1 % and the fraction of C4 was decreased from 0.9 % to 0.4 %. By this process the light NG product dew point was reduced from −9.5 to −58 °C and the molar fraction of C4+ in the liquid product was reached to 43.5 %, whereas it was only 1.6 % in the initial natural gas.

Investigations on the effect of spacer in direct contact and air gap membrane distillation using computational fluid dynamics

Direct contact membrane distillation (DCMD) and air gap membrane distillation (AGMD) have emerged as potential technologies for water and wastewater treatment. This investigation developed a comprehensive two-dimensional computational fluid dynamics model to describe and simulate heat transfer, mass transfer, and fluid flow in DCMD and AGMD processes. The effect of Reynolds number, inlet feed temperature, and distance between two successive spacer filaments on the performance parameters such as mass flux, temperature polarisation, concentration polarisation, and thermal efficiency was investigated in this work. The feed and permeate side heat transfer coefficient increased with Re in the DCMD and AGMD models. The thickness of the velocity boundary layers reduced upon introducing spacers in the feed and permeate channels. The mass flux on the introduction of spacers increased in DCMD and AGMD models because the boundary layer resistance was reduced. The models with spacer showed a lower oncentration polarisation. DCMD model demonstrated a loweroncentration polarisation than the AGMD model as the former has higher mass flux than the latter leading to a higher solute concentration on the membrane surface. The thermal boundary layer was smaller in the spacer-filled channel because of the fluid mixing. In the AGMD model, the permeate side thermal boundary layer was unaffected because of the poor conductivity of air than water.

Study of pressure surge during priming phase of start transient in an initially unprimed pump-fed liquid rocket engine

In this paper, transient phenomenon during start up process of a pump fed liquid rocket engine is investigated through numerical simulation. The engine studied in this work is designed such that engine systems are not wetted with propellant until the engine is commanded to start. This is achieved by positioning the valves for propellant admission at the interface of test stand/flight stage and the engine. To evaluate engine performance during start transient for such systems, unsteady flow simulation was conducted using Method of Characteristics and equations for priming. The same has been reported in this work. The results indicated a brief period of abrupt pressure rise at pump upstream after opening of the propellant admission valves, during the process of priming of engine systems at valve downstream. The peak pressure obtained was significantly higher than the propellant tank pressure as well as the steady state pump suction pressure. The transitory pressure rise was found to occur due to flow resistance at impeller inlet caused by formation of a forced vortex for orienting the flow through impeller blades during off design transient regime. The maximum pressure at pump upstream, as computed from start transient simulation, was used as a design input for pump inlet feed lines. The engine was realized and subsequently qualified in a ground test facility. Hot test data obtained for pressure and flow rate during transient regime were found to be in good agreement with the simulation results.

Microencapsulation of oregano essential oil by spray-drying using maltodextrin: gum arabic blends

Abstract The effect of processing parameters on microencapsulation of oregano essential with maltodextrin:gum arabic using a disk atomiser spray-dryer was evaluated. By means of response surface methodology, the feed flow rate and inlet air temperature were optimised. Powder yield, moisture content, essential oil retention, and antioxidant activity of microparticles were evaluated. The best conditions to produce microencapsulated oregano essential oil were 0.6 L h−1 for feed flow rate and 200 °C for inlet air temperature. With this combination a microencapsulated powder with 89.8% powder yield, 2.1% moisture content, 92.1% essential oil retention, 76 s solubilisation time, 12.9 g of water/100 g of dry matter, 0.3371 g mL−1 bulk density, 0.5826 g mL−1 tapped density, and 8.2 μm of average particle size was produced. The microencapsulation of oregano essential oil preserves the antioxidant and antimicrobial activities of its bioactive compounds.

Effects of inlet operational parameters on the combined salt gradient solar pond-direct contact membrane distillation system

This paper focuses on the performance-analysis of a combined renewable energy system/desalination unit. The renewable energy system consists of a Salt Gradient Solar Pond (SGSP) for the collection and the storage of solar energy while the desalination process uses the Direct Contact Membrane Distillation (DCMD).DCMD processes operate practically at the same range of temperatures obtained from low temperature solar pond. However, while combining DCMD unit with a solar energy source, it is necessary to investigate the effect of energy source fluctuations on the operating parameters. The large fluctuations of solar intensity throughout the day will affect the inlet feed temperature of the DCMD process which in turn affects the permeate flux. The main objective of this study is to evaluate, numerically, the effects of inlet operational parameters on the solar driven combined system for production of fresh water. A mathematical model was built to predict the production rate from the measured temperatures of the Salt Gradient Solar Pond. Coupling the heat and mass transfer, through the membrane, the model with solar energy input is mainly based on the technology of a solar pond with a salt concentration gradient. This solar technology will not really be simulated. Indeed, temperature measurements obtained from solar pond will serve as a basis inputs of the simulation. Obtained results showed that permeate flux increases with Lower Convective Zone (LCZ) temperature of the SGSP and the sundial during the day for a year, but it was less sensitive to the Upper Convective Zone (UCZ) temperature of the SGSP and to the feed water salinity.

Multi-objective optimization of a direct contact membrane distillation regenerator for liquid desiccant regeneration

Improving the performance of direct contact membrane distillation (DCMD) for liquid desiccant regeneration has attracted increasing attention. This paper presents multi-objective optimization of a DCMD regenerator to maximize its regeneration capacity (RC) and thermal efficiency (TE) simultaneously when treating a 25–30 wt.% lithium chloride desiccant solution. The key parameters, including initial feed concentration, feed and distillate inlet temperatures and volumetric flow rate were optimized using two methods (i.e. non-dominated sorting genetic algorithm (NSGA-Ⅱ) based method and a fuzzy clustering and weighted cumulative probability distribution (FC-WCPD) technique). The first method obtained an optimal Pareto front, in which the RC and TE were in the ranges of 0.77–0.91 wt.% and 12.2%–13.3%, respectively. The feed and distillate inlet temperatures showed a conflicting effect on enhancing the two objectives, while the initial feed concentration and volumetric flow rate were near their lower limits. Despite nearly identical results being obtained, the FC-WCPD technique can directly compute the compromised optimal solution without the aid of a multi-criteria decision-making process in comparison with the NSGA-Ⅱ-based method. The multi-objective optimization can effectively improve the overall performance of the DCMD regenerator as compared to the single-objective optimization, i.e. 4.9% higher in TE and 1.1% lower in RC than that optimizing the RC only; a 16.9% increase in RC and a 3.8% decrease in TE when compared to that optimizing the TE only.