The Experts below are selected from a list of 13137 Experts worldwide ranked by ideXlab platform
Shabina Khanam - One of the best experts on this subject based on the ideXlab platform.
-
Simulation of heat integrated multiple effect Evaporator System
International Journal of Thermal Sciences, 2014Co-Authors: Ghoshna Jyoti, Shabina KhanamAbstract:Abstract In the present work a number of configurations and difficulties of MEE System such as condensate flashing, vapor bleeding, steam splitting, preheating of liquor using condensate, variable physical properties and boiling point rise are taken into consideration to analyze the evaporation System. For this purpose seven effect Evaporator System of a typical Indian pulp and paper industry is considered. The model developed is a set of nonlinear algebraic equations that include total and solute mass balances, energy balances, heat transfer rate equations, and the composition and temperature dependence of thermodynamic properties such as vapor pressures and enthalpies. The model is solved using nonlinear equation solver. Economic evaluation to optimize the number of flash tanks is carried out for seven effect Evaporator System. The two different types of configurations of vapor bleeding are considered and compared. Considering optimum number of flash tanks and best configuration of vapor bleeding, a System is designed. Further, a modified System is found considering optimum number of flash tanks and preheating of liquor using condensate. This modified design enhances the steam economy by 23.77% and reduces the steam consumption by 36.76% in comparison to base case and thus, it is selected as optimum design. Finally, Pinch analysis of the MEE network has also been carried out and it is found that predicted results are compared well with base case.
-
Development of a new model for multiple effect Evaporator System
Computers & Chemical Engineering, 2011Co-Authors: Shabina Khanam, Bikash MohantyAbstract:Abstract A new simplified scalable mathematical model, based on concepts of stream analysis, temperature paths and internal heat exchange, has been developed for synthesis of a multiple effect Evaporator Systems. In this model, fresh feed is assumed to be composed of product and number of condensate streams, which come out from different effects and these are treated as separate streams. For the present work a septuple effect flat falling film Evaporator System, used for concentrating black liquor in an Indian Kraft Pulp and Paper mill, has been considered. This System is being operated under backward sequence with condensate-, feed- and product-flashing as well as steam splitting in first two effects. The set of linear algebraic equations for this model are self-generated through programming and is solved simultaneously using Gaussian Elimination Method with partial pivoting. Results of the present approach are validated with published model and industrial data.
-
placement of condensate flash tanks in multiple effect Evaporator System
Desalination, 2010Co-Authors: Shabina Khanam, Bikash MohantyAbstract:Abstract A scalable new model is developed for the analysis of multiple effect Evaporator (MEE) Systems with the induction of condensate flashing. It uses the concepts of stream analysis and temperature path for the formulation of model equations. In addition to above the model also takes into account boiling point rise and variable physico-thermal properties of steam/vapor condensate and liquor while simulating the MEE System. The present model consists of linear equations, which are automatically generated through temperature path. To establish the reliability of the present model it was run for four different case studies and the results are compared well with the published models. This paper shows the trade-off between annual capital and operating costs, which decides optimum number of flash tanks as well as their positions in the MEE System.
-
simulation of flat falling film Evaporator System for concentration of black liquor
Computers & Chemical Engineering, 2008Co-Authors: Ravindra Bhargava, Shabina Khanam, Bikash MohantyAbstract:Abstract In the present investigation, a non-linear mathematical model is developed for the analysis of Septuple effect flat falling film Evaporator (SEFFFE) System used for concentrating black liquor in a nearby paper mill. This model is capable of simulating process of evaporation considering variations in boiling point rise ( τ ), overall heat transfer coefficient ( U ), heat loss ( Q loss ), flow sequences, liquor/steam splitting, feed, product and condensate flashing, vapor bleeding and physico-thermal properties of the liquor. Based on mass and energy balance around an effect a cubic polynomial is developed and solved repeatedly in a predetermined sequence using generalized cascade algorithm. For development of empirical correlations for τ , U and Q loss , plant data have been collected from SEFFFE System. These correlations compute τ , U and Q loss within average absolute errors of 2.4%, 10% and 33%, respectively, when their results are compared with the plant data.
-
selection of optimal feed flow sequence for a multiple effect Evaporator System
Computers & Chemical Engineering, 2008Co-Authors: Ravindra Bhargava, Shabina Khanam, Bikash Mohanty, A K RayAbstract:Abstract A nonlinear model is developed for a SEFFFE System employed for concentrating weak black liquor in an Indian Kraft Paper Mill. The System incorporates different operating strategies such as condensate-, feed- and product-flashing, and steam- and feed-splitting. This model is capable of simulating a MEE System by accounting variations in τ, U, Qloss, physico-thermal properties of the liquor, F and operating strategies. The developed model is used to analyze six different F including backward as well as mixed flow sequences. For these F, the effects of variations of input parameters, T0 and F, on output parameters such as SC and SE have been studied to select the optimal F for the complete range of operating parameters. Thus, this model is used as a screening tool for the selection of an optimal F amongst the different F. An advantage of the present model is that a F is represented using an input Boolean matrix and to change the F this input matrix needs to be changed rather than modifying the complete set of model equations for each F. It is found that for the SEFFFE System, backward feed flow sequence is the best as far as SE is concerned.
Reinhard Radermacher - One of the best experts on this subject based on the ideXlab platform.
-
comprehensive investigation of numerical methods in simulating a steady state vapor compression System
International Journal of Refrigeration-revue Internationale Du Froid, 2008Co-Authors: Jonathan Winkler, Vikrant Aute, Reinhard RadermacherAbstract:Computer simulation has become a required tool in the design phase of vapor compression Systems; however with relatively few exceptions most simulations focus on the basic four component Systems. With an increasing focus being placed on energy efficiency, the simulation of multi-component vapor compression Systems (having multiple Evaporators, condenser or compressors) will become essential to assist in the design of these more complicated Systems. The implementation of a component-based framework will facilitate the simulation of multi-component Systems. This paper describes three algorithms used to simulate a component-based vapor compression System. A test matrix of 6174 sample runs covering a wide range of operating conditions was constructed to determine the robustness and speed of each method when using three different types of nonlinear equation solvers. Each method was tested by simulating a basic four component cycle and a more advanced multiple Evaporator System. The results are presented in such a format as to describe the reasons that contribute to any instability of the solvers and the computational efficiency of each method is discussed.
Bikash Mohanty - One of the best experts on this subject based on the ideXlab platform.
-
Development of a new model for multiple effect Evaporator System
Computers & Chemical Engineering, 2011Co-Authors: Shabina Khanam, Bikash MohantyAbstract:Abstract A new simplified scalable mathematical model, based on concepts of stream analysis, temperature paths and internal heat exchange, has been developed for synthesis of a multiple effect Evaporator Systems. In this model, fresh feed is assumed to be composed of product and number of condensate streams, which come out from different effects and these are treated as separate streams. For the present work a septuple effect flat falling film Evaporator System, used for concentrating black liquor in an Indian Kraft Pulp and Paper mill, has been considered. This System is being operated under backward sequence with condensate-, feed- and product-flashing as well as steam splitting in first two effects. The set of linear algebraic equations for this model are self-generated through programming and is solved simultaneously using Gaussian Elimination Method with partial pivoting. Results of the present approach are validated with published model and industrial data.
-
placement of condensate flash tanks in multiple effect Evaporator System
Desalination, 2010Co-Authors: Shabina Khanam, Bikash MohantyAbstract:Abstract A scalable new model is developed for the analysis of multiple effect Evaporator (MEE) Systems with the induction of condensate flashing. It uses the concepts of stream analysis and temperature path for the formulation of model equations. In addition to above the model also takes into account boiling point rise and variable physico-thermal properties of steam/vapor condensate and liquor while simulating the MEE System. The present model consists of linear equations, which are automatically generated through temperature path. To establish the reliability of the present model it was run for four different case studies and the results are compared well with the published models. This paper shows the trade-off between annual capital and operating costs, which decides optimum number of flash tanks as well as their positions in the MEE System.
-
simulation of flat falling film Evaporator System for concentration of black liquor
Computers & Chemical Engineering, 2008Co-Authors: Ravindra Bhargava, Shabina Khanam, Bikash MohantyAbstract:Abstract In the present investigation, a non-linear mathematical model is developed for the analysis of Septuple effect flat falling film Evaporator (SEFFFE) System used for concentrating black liquor in a nearby paper mill. This model is capable of simulating process of evaporation considering variations in boiling point rise ( τ ), overall heat transfer coefficient ( U ), heat loss ( Q loss ), flow sequences, liquor/steam splitting, feed, product and condensate flashing, vapor bleeding and physico-thermal properties of the liquor. Based on mass and energy balance around an effect a cubic polynomial is developed and solved repeatedly in a predetermined sequence using generalized cascade algorithm. For development of empirical correlations for τ , U and Q loss , plant data have been collected from SEFFFE System. These correlations compute τ , U and Q loss within average absolute errors of 2.4%, 10% and 33%, respectively, when their results are compared with the plant data.
-
selection of optimal feed flow sequence for a multiple effect Evaporator System
Computers & Chemical Engineering, 2008Co-Authors: Ravindra Bhargava, Shabina Khanam, Bikash Mohanty, A K RayAbstract:Abstract A nonlinear model is developed for a SEFFFE System employed for concentrating weak black liquor in an Indian Kraft Paper Mill. The System incorporates different operating strategies such as condensate-, feed- and product-flashing, and steam- and feed-splitting. This model is capable of simulating a MEE System by accounting variations in τ, U, Qloss, physico-thermal properties of the liquor, F and operating strategies. The developed model is used to analyze six different F including backward as well as mixed flow sequences. For these F, the effects of variations of input parameters, T0 and F, on output parameters such as SC and SE have been studied to select the optimal F for the complete range of operating parameters. Thus, this model is used as a screening tool for the selection of an optimal F amongst the different F. An advantage of the present model is that a F is represented using an input Boolean matrix and to change the F this input matrix needs to be changed rather than modifying the complete set of model equations for each F. It is found that for the SEFFFE System, backward feed flow sequence is the best as far as SE is concerned.
-
mathematical model for a multiple effect Evaporator System with condensate feed and product flash and steam splitting
Indian Journal of Chemical Technology, 2008Co-Authors: Ravindra Bhargava, Shabina Khanam, Bikash Mohanty, Amiya K RayAbstract:In the present investigation a non-linear mathematical model is developed for the analysis of multiple effect Evaporators (MEE) System. This model is capable of simulating process of evaporation and takes into account variations in -boiling point rise (BPR) due to variation in concentration and temperature of liquor, -overall heat transfer coefficient (OHTC) of effects and -physico-thermal property of the liquor. Using mass and energy balance around an effect, a cubic polynomial equation is developed to model an effect, which is solved using generalized cascade algorithm. For this purpose, a Septuple effect flat falling film Evaporator (SEFFFE) System with backward feed flow sequence, being used for concentrating weak black liquor and operating in a near by paper mill, is selected as a typical MEE System. This System supports different operating strategies such as steam splitting and condensate-, feed- and product- flashing. The empirical correlations for BPR, OHTCs of flat falling film Evaporators and heat loss have been developed using the plant data. Using these correlations, average errors of 3.4%, ± 10% and -33 to +29% have been observed for the predictions of BPR, OHTC and heat loss, respectively.
Arun S. Mujumdar - One of the best experts on this subject based on the ideXlab platform.
-
On the steady-state modelling of a two-stage Evaporator System
International Journal of Energy Research, 2001Co-Authors: Mohammad Nurul Alam Hawlader, Siaw Kiang Chou, Kian Jon Chua, Arun S. MujumdarAbstract:We develop and validate against experimental measurements a steady-state two-stage flooded refrigerant Evaporator model for a heat pump drying System. A prototype two-stage heat pump dryer test facility was designed, built and instrumented to provide the required measurements for the validation of the model. Repeatability and data quality tests were conducted to evaluate the accuracy of measurements. Experimental data could be reproduced to within ±6.5 per cent of replicated air and refrigerant side measurements for the same Evaporator's air inlet conditions while the discrepancy of energy balance at the air-side and refrigerant-side was observed to be within ±8.9 per cent. The two-stage Evaporator model predicted the air-side total heat and latent heat transfer of the two-stage Evaporator to within (−6.3 per cent, 7.6 per cent) and (−11.5 per cent, 9.5 per cent), respectively. On the refrigerant-side, the model enabled the calculation of the degree of superheat to within (−10.6 per cent, 1.7 per cent). The model has shown that there is significant improvement in the heat recovered from a two-stage Evaporator System compared to a single Evaporator System. In addition, the model demonstrated that the improvement in total heat recovery could be as high as 40 per cent over its base-value when the latent to total load at the two-stage Evaporator is increased. Copyright © 2001 John Wiley & Sons, Ltd.
Jonathan Winkler - One of the best experts on this subject based on the ideXlab platform.
-
comprehensive investigation of numerical methods in simulating a steady state vapor compression System
International Journal of Refrigeration-revue Internationale Du Froid, 2008Co-Authors: Jonathan Winkler, Vikrant Aute, Reinhard RadermacherAbstract:Computer simulation has become a required tool in the design phase of vapor compression Systems; however with relatively few exceptions most simulations focus on the basic four component Systems. With an increasing focus being placed on energy efficiency, the simulation of multi-component vapor compression Systems (having multiple Evaporators, condenser or compressors) will become essential to assist in the design of these more complicated Systems. The implementation of a component-based framework will facilitate the simulation of multi-component Systems. This paper describes three algorithms used to simulate a component-based vapor compression System. A test matrix of 6174 sample runs covering a wide range of operating conditions was constructed to determine the robustness and speed of each method when using three different types of nonlinear equation solvers. Each method was tested by simulating a basic four component cycle and a more advanced multiple Evaporator System. The results are presented in such a format as to describe the reasons that contribute to any instability of the solvers and the computational efficiency of each method is discussed.