@article { ISI:000229380600016, title = {Performance assessment of HC-290 as a drop-in substitute to HCFC-22 in a window air conditioner}, journal = {International Journal of Refrigeration - Revue Internationale Du Froid}, volume = {28}, number = {4}, year = {2005}, month = {JUN}, pages = {594-604}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

As per the Montreal Protocol, CFCs and HCFCs are being phased out. HCFC-22 is used in window air conditioners. This paper presents the experimental performance study of a window air conditioner with propane (HC-290), a natural refrigerant, as a drop-in substitute to HCFC-22. Experimental results showed that HC-290 had 6.6\% lower cooling capacity for the lower operating conditions and 9.7\% lower for the higher operating conditions with respect to HCFC-22. The coefficient of performance for HC290 was 7.9\% higher for the lower operating conditions and 2.8\% higher for the higher operating conditions. The energy consumption of the unit with HC-290 was lower in the range 12.4-13.5\% than HCFC-22. The discharge pressures for HC-290 were lower in the range 13.7-18.2\% than HCFC-22. For HC-290, the pressure drop was lower than HCFC-22 in both heat exchangers. This paper also presents simulation results for the heat exchangers of an HCFC-22 window air conditioner with HC-290 as a drop-in substitute. The simulation has been carried out using EVAP-COND, a heat exchanger model developed by NIST [National Institute of Standards and Technology. EVAP-COND: simulation models for finned-tube heat exchangers, Maryland, USA (2003). http://www2.bfrl.nist.gov/software/evap-cond/ [18]]. The simulated evaporator capacities are within +/- 4\% of the experimentally measured cooling capacities for both refrigerants. Simulation results for HC-290 and HCFC-22 are compared. The exit temperatures of HC-290 are lower by 0.3-1.2 degrees C in the condenser and are higher by 2.1-2.4 degrees C in the evaporator than HCFC-22. Evaporating pressures of HC-290 are lower by 2.1-3.3\% as compared to HCFC-22. The pressure drops of HC-290 are lower in both the evaporator and the condenser as compared to HCFC-22. The outlet temperatures of air for HCFC-22 and HC-290 in both heat exchangers are nearly the same. (c) 2005 Elsevier Ltd and IIR. All rights reserved.

}, keywords = {air conditioner, COP, Evaporator, experiment, performance, propane, R-22, simulation, window}, issn = {0140-7007}, doi = {10.1016/j.ijrefrig.2004.09.013}, author = {Devotta, S and Padalkar, AS and Sane, NK} } @article {44012, title = {Study of the effect of operating parameters on the extractive distillation of isopropyl alcohol{\textendash}water mixture using dimethyl sulphoxide as an entrainer}, journal = {Indian Chemical Engineer}, volume = {60}, year = {2017}, month = {MAY}, pages = {141-161}, type = {Journal Article}, chapter = {1-21}, abstract = {

Abstract: In this paper, the simulation analysis of separation of isopropyl alcohol (IPA){\textendash}water via extractive distillation by using dimethyl sulphoxide as an entrainer is presented. The steady-state simulation for this process was done using Aspen Plus simulator. The aim of this work is to study the effect of various operating parameters such as number of stages, molar reflux ratio, binary feed stage number, entrainer feed stage number, temperature of entrainer feed and entrainer to feed molar ratio on the purity and energy consumption. The sensitivity of these parameters serves as a basis to choose the optimum operating conditions to maximize the IPA purity and minimize the energy requirement. In this analysis, among various operating parameters, those which directly affect the IPA purity and the parameters which affect the reboiler duty, for the given separation task, are identified. Simulation results with optimum operating conditions and their economic analysis are also presented.

}, keywords = {Aspen Plus Simulators, Azeotrope, Computer software, Distillation, Energy requirements, Energy utilization, Extractive distillation, Isopropyl alcohol/water, Isopropyl alcohols, Operating parameters, Optimum operating conditions, Sensitivity analysis, simulation, SimulationSteady-state simulations, Solvents}, issn = {0019-4506}, doi = {10.1080/00194506.2017.1322923}, author = {Ghuge, Pravin D. and Mali, Nilesh A. and Sirsam, R. S.} } @article {45696, title = {Study of thermally coupled distillation systems for energy-efficient distillation}, journal = {Sadhana-Academy Proceedings in Engineering Sciences}, volume = {42}, year = {2017}, month = {JAN}, pages = {119-128}, type = {Article}, abstract = {

Distillation is one of the most widely used separation unit operations in process industries, although it is quite energy intensive. In many cases, the enormous energy requirements for distillation make it economically infeasible to carry out the separation. Thermally coupled distillation system (TCDS) is an advanced distillation method that provides significant energy savings of about 30\% as compared with conventional distillation column sequences. The most well-known TCDS sequence, the Petlyuk configuration, has some operational challenges due to bidirectional vapour flow, which makes its implementation difficult in two-column mode. To overcome these limitations, a number of unidirectional vapour flow configurations have been proposed in the literature. The work on simulation analysis for such configurations is limited. In this paper, simulation models for two such configurations are developed, analyzed and compared with the Petlyuk and conventional distillation column sequences for separation of equimolar mixture of benzene-toluene-ethylbenzene.

}, keywords = {Distillation, energy efficient, Petlyuk, simulation, thermally coupled}, issn = {0256-2499}, doi = {10.1007/s12046-016-0580-x}, author = {Saxena, Neha and Mali, Nilesh and Satpute, Satchidanand} } @article {47135, title = {Energy and life cycle impact assessment for xylitol production from corncob}, journal = {Journal of Cleaner Production}, volume = {278}, year = {2021}, month = {JAN }, pages = {123217}, type = {Article}, abstract = {

The conversion of biobased feedstocks into energy and value-added chemicals is one main approach to address the current global challenge for waste mitigation through the biorefinery mode. Corncob biomass which is one of the most abundant agricultural residue in India with a high hemicellulose content, can serve as a potential low-cost raw material for food-grade xylitol production. The present study demonstrates a process for xylitol production from corncob biomass with detailed energy and life cycle analysis for viability assessment. The major highlight of the process is the use of microbial fermentation, where biomass-derived D-xylose is converted to xylitol with high selectivity. Overall, 0.502 kg of xylitol crystals could be produced from 3.5 kg of corncob biomass. Simulation analysis revealed that the evaporators are the primary consumers of energy, and the process of heat integration can significantly reduce the energy requirements of the overall process. Environmental impacts of the system evaluated showed emission results of 8.68 kg CO2 equivalent and revealed that marine aquatic and freshwater eco-toxicity are the only possible contributors to the environment. The results suggest that the process would have favourable energy balances, which can be used in pilot plant and heat exchanger network design and operation for xylitol production scale up to 500 L. (C) 2020 Elsevier Ltd. All rights reserved.

}, keywords = {biomass valorization, Life cycle impact assessment, simulation, xylitol}, issn = {0959-6526}, doi = {10.1016/j.jclepro.2020.123217}, author = {Dasgupta, Diptarka and Sidana, Arushdeep and Ghosh, Prasenjit and Sharma, Tripti and Singh, Jasvinder and Prabhune, Asmita and More, Snehal and Bhaskar, Thallada and Ghosh, Debashish} } @article {48394, title = {Mechanistic modeling of continuous capture step purification of biosimilar monoclonal antibody therapeutic}, journal = {Journal of Chemical Technology and Biotechnology}, volume = {97}, year = {2022}, month = {SEP}, pages = {2404-2419}, type = {Article}, abstract = {

{BACKGROUND Continuous multicolumn Protein A chromatography offers various advantages for capture stage purification of monoclonal antibody therapeutics, like higher productivity and resin capacity utilization, lower buffer consumption, small footprint, etc. Due to the complexity of the continuous process, experimental optimization is time-consuming and cost-intensive. This investigation proposes a hybrid process development approach integrating experimental and mechanistic modeling for time- and cost-effective development and optimization of continuous Protein A affinity chromatography. RESULTS Productivity and capacity utilization of the continuous CaptureSMB process under varying operating conditions were predicted using the Chromatography Analysis and Design Toolkit (CADET) framework and validated with experimental results. Effects of critical process parameters like feed concentration (c(0)), loading breakthrough (s) and residence time (RT) on productivity and capacity utilization were evaluated. Model predictions were validated using the experimental results proving the reliability and feasibility of the modeling approach. At 15.00 +/- 0.20 mg mL(-1) feed model mAb concentration, the model-based approach predicted the best performance giving 27.56 g L-1 h(-1) productivity (RT = 2 min

}, keywords = {CaptureSMB, continuous chromatography, Mathematical modeling, Protein A, simulation}, issn = {0268-2575}, doi = {10.1002/jctb.6922}, author = {Deulgaonkar, Prashant and Bhambure, Rahul and Prasad, Bhaskarjyoti and Mishra, Ashok and Tiwari, Sanjay and Mody, Rustom} } @article {47991, title = {Optimization of Liquid Organic Hydrogen Carrier (LOHC) dehydrogenation system}, journal = {International Journal of Hydrogen Energy}, volume = {47}, year = {2022}, month = {AUG}, pages = {28530-28547}, type = {Article}, abstract = {

In this paper, the perhydrodibenzyltoluene dehydrogenation flowsheet has been simulated. Modelling of the dehydrogenation reactor has been performed using the 1-D model. External and internal mass transfer resistances are also considered. Non-isothermal pellet condition has been considered for simulating the dehydrogenation reactor. The flowsheet simulation has been carried out in DW-Sim v 6.5.2 integrated with the reactor model coded in Python. NET. The dehydrogenation reactor is operated at a feed temperature between 523 K -613 K, a wall temperature of 623 K and 653 K, and a reactor pressure maintained at 1.2 atm. The amount of catalyst required for the perhydrodibenzyltoluene (PDBT) dehy-drogenation reactor is evaluated such that the conversion reaches 99\%. The process flowsheet has been simulated to produce 10 Nm(3)/hr of industrial-grade hydrogen. The effects of feed temperature, wall temperature, and hydrogen burner efficiency on various system requirements, including catalyst weight, energy supplied to the dehydrogenation reactor, areas of the heat exchanger, and hydrogen production from the reactor, have been discussed. Preliminary cost optimization based on the heat exchangers and catalyst at various feed temperatures, reactor wall temperature, and hydrogen burner efficiency has been carried out. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Dehydrogenation, DWSim, LOHC, Perhydrodibenzyltoluene, Python, simulation}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2022.06.197}, author = {Rao, Nihal and Lele, Ashish K. and Patwardhan, Ashwin W.} }