Modelling of Shell and Tube Transport Membrane Condenser Heat Exchangers in Low Grade Waste Heat and Water Recovery Applications

Author(s):  
Soheil Soleimanikutanaei ◽  
Esmaiil Ghasemisahebi ◽  
Cheng-Xian Lin ◽  
Dexin Wang

In this study Transport Membrane Condenser (TMC), a new waste heat and water recovery technology based on a nanoporous ceramic membrane vapor separation mechanism has been studied for waste heat and water recovery in power plant application. TMC is able to extract condensate pure water from the flue gas in the presence of other non-condensable gases (i.e. CO2, O2 and N2). The effects of mass flow rate of flue gas and water vapor content of flow on the heat transfer and condensation rate of a TMC shell and tube heat exchanger have been studied numerically. A single phase multi-component model is used to assess the capability of single stage TMC heat exchangers in terms of waste heat and water recovery at various inlet conditions. Numerical simulation has been performed using ANSYS-FLUENT software and the condensation rate model has been implemented applying User Define Function.

Author(s):  
Esmaiil Ghasemisahebi ◽  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang

In this study tube bundle Transport Membrane Condenser (TMC) has been studied numerically. The tube walls of TMC based heat exchangers are made of a nano-porous material and has a high membrane selectivity which is able to extract condensate pure water from the flue gas in the presence of other non-condensable gases (i.e. CO2, O2 and N2). Low grade waste heat and water recovery using ceramic membrane, based on separation mechanism, is a promising technology which helps to increase the efficiency of boilers and gas or coal combustors. The effects of inclination angles of tube bundle, different flue gas velocities, and the mass flow rate of water and gas flue have been studied numerically on heat transfer, pressure drop and condensation rates. To assess the capability of single stage TMC heat exchangers in terms of waste heat and water recovery at various inlet conditions, a single phase multi-component model is used. ANSYS-FLUENT is used to simulate the heat and mass transfer inside TMC heat exchangers. The condensation model and related source/sink terms are implemented in the computational setups using appropriate User Defined Functions (UDFs).


Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang

In this work for the first time the performance of multi-stage shell and tube Transport Membrane Condenser (TMC) based heat exchangers are evaluated numerically. The present heat exchanger is design to work under high pressure and temperature condition for both heat and water recovery in Oxy-Combustion processes. TMC heat exchangers use the nano-porous and ceramic membrane technology to extract the water vapor and latent heat of condensation from the flue-gas. The most important application of TMC heat exchangers is in the power plants which the water vapor in the presence of other non-condensable gases (i.e. CO2, O2 and N2) exist. Effect of the different arrangement of the multi-stage shell and tube TMC heat exchangers, number of branches and number of heat exchangers in each branch on the heat transfer and water recovery have been studied numerically. A single phase multi-component model is used to assess the capability of single stage TMC heat exchangers in terms of waste heat and water recovery at various inlet conditions. Numerical simulation has been performed using ANSYS-FLUENT software and the condensation rate model has been implemented applying User Define Function. Finally, an optimum configuration for the TMC heat exchanger unit has been proposed and the results of numerical simulations are depicted in terms of temperature and water vapor mass fraction contours.


Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang

In this paper, the effects of different working conditions on the performance of Transport Membrane Condenser (TMC) based heat exchangers are studied numerically. The effects of non-condensable gases on the condensation rate along with the number and distances of the TMC tubes in longitudinal and transversal directions were investigated. The numerical simulations have been conducted using the commercial software Ansys Fluent 14.5 and the condensation and heat and mass transfer are implemented using User Defined Functions (UDFs) in the numerical setup. The RNG two-equation turbulence model is used to handle heat, mass and momentum transfer across the TMC bundle tubes. The results are depicted in terms of volume fraction of water vapor and averaged outlet temperature of cooling water and flue gas. The results revealed that increase of the number of TMC tubes, when the inlet flow rate is constant, increases both the condensing surface area and average surface temperature which have opposite effects on the condensation rate, hence both of these parameters should be considered in industrial applications.


Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang

Low grade waste heat and water recovery using ceramic membrane, is an emerging technology which helps to increase the efficiency of boilers and gas or coal combustors in various industrial processes and conventional power plants. The tube wall of a Transport Membrane Condenser (TMC) based heat exchanger is made of a nano-porous material with high membrane selectivity which is able to extract condensate water from the flue gas in the presence of other non-condensable gases (i.e. CO2, O2 and N2). In this work, a numerical study has been carried out to investigate the effects of transversal pitches of the TMC bundle tubes on the performance of a TMC based cross flow heat exchanger. A simplified multi-species transport model is used to investigate the heat and mass transfer characteristics of a condensing combustion flue gas in a crossflow transport membrane tube bundle. Various transversal (0.4”–0.6”) and longitudinal (0.4”–0.8”) pitches were used. The numerical results revealed that the effect of transversal pitches on the outlet parameters are more pronounced.


2017 ◽  
Author(s):  
Roman Gášpár ◽  
Stanislav Souček

A cogeneration unit is a device for the production of electricity and heat. Waste heat is used in the cogeneration (Combine Heat and Power or CHP) process. This process increases the efficiency of the whole cogeneration unit system. One of the most important parts of a cogeneration unit is the exhaust heat exchanger, where waste heat is recovered. The objective of this applied research is to examine the properties of a shell-and-tube heat exchanger for a CHP unit of up to 200 kW manufactured by TEDOM a.s. The computations presented in this article are the results of computations where the influence of the composition of flue gas entering the computation in comparison with measured quantities were examined. The article contains a comparison of the influence of the flue gas, represented by CO2, N2 and air as an ideal gas. The results include an analysis of the character of the flow in the heat exchanger, especially in the input volume of the flue gas, where, apart from the influence of the flue gas properties, the influence of the construction on the flue gas mass flow rate distribution into the tubes was also examined. The advantage of this extensive computation lies in the possibility of a detailed analysis of particular parts of the heat exchanger as well as the possibility of detecting potential construction imperfections, which could negatively influence heat transfer and hence the total efficiency of the heat exchanger and the CHP unit.


Shell and Tube Heat Exchangers (STHEs) plays a crucial role in an effective design of Organic Rankine Cycle (ORC) power plants.The main aim of this research work is to design a cost-effective ORC in order to exploit low to medium temperature geothermal fluid or low grade industrial waste heat. In this research work, modified Kinetic Gas Molecule Optimization (KGMO) algorithm was developed forfinding the optimized parameter settings of the power plant. In modified KGMO algorithm, feedback learning stage was included for improving the fitness of individual worst particles. In addition, the proposed optimization algorithm was tested on two dissimilar fluids such asR245fa and R134a in order to show the effectiveness of proposed scheme. The experimental investigation showed that the proposed scheme effectively improved the heat exchanger performance as related to the existing schemes.The enhancement factor of proposed scheme was 2.8063 for R245fa fluid and 1.9346 for R134a fluid, which was better compared to the existing schemes; KGMO and Bell-Delaware method.


1988 ◽  
Vol 110 (1) ◽  
pp. 54-59 ◽  
Author(s):  
A. Pignotti ◽  
P. I. Tamborenea

The thermal effectiveness of a TEMA E shell-and-tube heat exchanger, with one shell pass and an arbitrary number of tube passes, is determined under the usual symplifying assumptions of perfect transverse mixing of the shell fluid, no phase change, and temperature independence of the heat capacity rates and the heat transfer coefficient. A purely algebraic solution is obtained for the effectiveness as a function of the heat capacity rate ratio and the number of heat transfer units. The case with M shell passes and N tube passes is easily expressed in terms of the single-shell-pass case.


Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3276 ◽  
Author(s):  
Jan Wajs ◽  
Michał Bajor ◽  
Dariusz Mikielewicz

In this paper a patented design of a heat exchanger with minijets, with a cylindrical construction is presented. It is followed by the results of its systematic experimental investigations in the single-phase convection heat transfer mode. Based on these results, validation of selected correlations (coming from the literature) describing the Nusselt number was carried out. An assessment of the heat exchange intensification level in the described heat exchanger was done through the comparison with a shell-and-tube exchanger of a classical design. The thermal-hydraulic characteristics of both units were the subjects of comparison. They were constructed for the identical thermal conditions, i.e., volumetric flow rates of the working media and the media temperatures at the inlets to the heat exchanger. The experimental studies of both heat exchangers were conducted on the same test facility. An increase in the heat transfer coefficients values for the minijets heat exchanger was observed in comparison with the reference one, whereas the generated minijets caused greater hydraulic resistance. Experimentally confirmed intensification of heat transfer on the air side, makes the proposed minijets heat exchanger application more attractive, for the waste heat utilization systems from gas sources.


Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang

Heat and water recovery using Transport Membrane Condenser (TMC) based heat exchangers is a promising technology in power generation industry. In this type of innovative heat exchangers the tube walls are made of a nano-porous material and have a high membrane selectivity which is able to extract condensate water from the flue gas in the presence of the other non-condensable gases such as CO2, O2 and N2. Considering the fact that for industrial applications, a matrix of TMC heat exchangers with several TMC modulus in the cross section or along the flow direction is necessary. Numerical simulation of multi-stage TMC heat exchanger units is of a great importance in terms of design, performance evaluation and optimization. In this work, performance of a two-stage TMC heat exchanger unit has been studied numerically using a multi-species transport model. In order to investigate the performance of the two-stage TMC heat exchanger unit, parametric study on the effect of transversal and longitudinal pitches in terms of heat transfer, pressure drop and condensation rate inside the heat exchangers have been carried out. The results indicate that the heat transfer and condensation rates both increase by reducing TMC tube pitches in the second stage and increasing the number of TMC tube pitches in the first stage of the units.


Sign in / Sign up

Export Citation Format

Share Document