Numerical Study of Transport Membrane Condenser Heat Exchangers

2016 ◽  
Author(s):  
Esmaiil Ghasemisahebi ◽  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang
Keyword(s):  
Flue Gas ◽  
Heat Exchangers ◽  
Ceramic Membrane ◽  
Waste Heat ◽  
Numerical Study ◽  
Tube Bundle ◽  
Pure Water ◽  
Separation Mechanism ◽  
Low Grade ◽  
Water Recovery

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).

Numerical Simulation of Low Grade Heat and Water Recovery Using Nanoporous Transport Membrane Condensers Bundle Tubes

2015 ◽  
Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang
Keyword(s):  
Heat Exchanger ◽  
Flue Gas ◽  
Power Plants ◽  
Ceramic Membrane ◽  
Transport Model ◽  
Waste Heat ◽  
Numerical Study ◽  
Tube Bundle ◽  
Low Grade ◽  
Water Recovery

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.

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

2016 ◽  
Author(s):  
Soheil Soleimanikutanaei ◽  
Esmaiil Ghasemisahebi ◽  
Cheng-Xian Lin ◽  
Dexin Wang
Keyword(s):  
Flue Gas ◽  
Heat Exchangers ◽  
Waste Heat ◽  
Pure Water ◽  
Separation Mechanism ◽  
Low Grade ◽  
Water Recovery ◽  
Condensation Rate ◽  
Tube Heat Exchanger ◽  
Shell And Tube

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.

Performance Evaluation of Multi-Stage Shell and Tube Transport Membrane Condenser Heat Exchangers for Low Grade Waste Heat and Water Recovery

2017 ◽  
Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang
Keyword(s):  
Water Vapor ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Power Plants ◽  
Ceramic Membrane ◽  
Waste Heat ◽  
Low Grade ◽  
Water Recovery ◽  
Multi Stage ◽  
Shell And Tube

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.

Numerical Modeling and Simulation of Condensation Heat Transfer in a Bundle of Transport Membrane Tubes for Waste Heat and Water Recovery

2011 ◽  
Author(s):  
Cheng-Xian Charlie Lin ◽  
Dexin Wang ◽  
Ainan Bao
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Flue Gas ◽  
Transport Model ◽  
Waste Heat ◽  
Numerical Study ◽  
Tube Bundle ◽  
Inlet Temperature ◽  
Water Recovery ◽  
Species Transport

In this paper, a numerical study has been carried out to investigate the heat and mass transfer with condensation in a transport membrane tube bundle, which is used for recovering both heat and water from combustion flue gas. The tube wall is made of a specially designed porous material that is able to extract condensate liquid from the flue gas. The flue gas investigated consists of one condensable water vapor (H2O) and three noncondensable gases (CO2, O2, and N2). A simplified multi-species transport model was developed for the heat and mass transfer of flue gas. The condensation-evaporation process was simulated as a two-step chemical reaction. The RNG two-equation turbulence model was used for the turbulent flow. The numerical study was conducted within ranges of Reynolds number of 1.0×103–7×104 based on hydraulic diameter of flue gas channel, and 6.4×100–3.3×102 based on inner diameter of the water tube. Flue gas inlet temperature is within the range of 333.2–360.9 K, while the water inlet temperature is within the range of 293.9–316.7 K. Numerical results were compared with experimental data obtained in a parallel effort. It has been found that the developed multi-species transport model was able to predict the flue gas heat and mass transfer in the tube bundle with fairly good accuracy. The heat and mass depletion levels decrease with the increase of the flue gas Reynolds numbers. A new Nusselt number correlation was developed for flue gas convection in the tube bundle. Detailed results about temperature, mass fraction, enthalpy, and skin fraction factors are also presented and discussed.

scholarly journals Experimental Study on a Ceramic Membrane Condenser with Air Medium for Water and Waste Heat Recovery from Flue Gas

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 701
Author(s):  
Da Teng ◽  
Liansuo An ◽  
Guoqing Shen ◽  
Shiping Zhang ◽  
Heng Zhang
Keyword(s):  
Flue Gas ◽  
Negative Pressure ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Ceramic Membrane ◽  
Waste Heat ◽  
Outlet Temperature ◽  
Water Recovery ◽  
Cooling Medium ◽  
Transfer Characteristics

Ceramic membrane condensers that are used for water and waste heat recovery from flue gas have the dual effects of saving water resources and improving energy efficiency. However, most ceramic membrane condensers use water as the cooling medium, which can obtain a higher water recovery flux, but the waste heat temperature is lower, which is difficult to use. This paper proposes to use the secondary boiler air as the cooling medium, build a ceramic membrane condenser with negative pressure air to recover water and waste heat from the flue gas, and analyze the transfer characteristics of flue gas water and waste heat in the membrane condenser. Based on the experimental results, it is technically feasible for the ceramic membrane condenser to use negative pressure air as the cooling medium. The flue gas temperature has the most obvious influence on the water and heat transfer characteristics. The waste heat recovery is dominated by latent heat of water vapor, accounting for 80% or above. The negative pressure air outlet temperature of the ceramic membrane condenser can reach 50.5 °C, and it is in a supersaturated state. The research content of this article provides a new idea for the water and waste heat recovery from flue gas.

Numerical Modeling of Industrial Scale Transport Membrane Condenser Based Heat Exchangers for Flue Gas Waste Heat and Water Recovery

2015 ◽  
Author(s):  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang
Keyword(s):  
Flue Gas ◽  
Heat Exchangers ◽  
Volume Fraction ◽  
Waste Heat ◽  
Cooling Water ◽  
Industrial Applications ◽  
Outlet Temperature ◽  
Water Recovery ◽  
Condensation Rate ◽  
Ansys Fluent

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.

scholarly journals Performance Characteristics of Solid-Desiccant Evaporative Cooling Systems

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2574 ◽  
Author(s):  
Ramadas Narayanan ◽  
Edward Halawa ◽  
Sanjeev Jain
Keyword(s):  
Air Conditioning ◽  
Natural Ventilation ◽  
Waste Heat ◽  
Numerical Study ◽  
Evaporative Cooling ◽  
Peak Load ◽  
Dew Point ◽  
Low Grade ◽  
Subtropical Climate ◽  
Cooling Systems

Air conditioning accounts for up to 50% of energy use in buildings. Increased air-conditioning-system installations not only increase total energy consumption but also raise peak load demand. Desiccant evaporative cooling systems use low-grade thermal energy, such as solar energy and waste heat, instead of electricity to provide thermal comfort. This system can potentially lead to significant energy saving, reduction in carbon emissions, and it has a low dew-point operation and large capacity range. Their light weight, simplicity of design, and close-to-atmospheric operation make them easy to maintain. This paper evaluates the applicability of this technology to the climatic conditions of Brisbane, Queensland, Australia, specifically for the residential sector. Given the subtropical climate of Brisbane, where humidity levels are not excessively high during cooling periods, the numerical study shows that such a system can be a potential alternative to conventional compression-based air-conditioning systems. Nevertheless, the installation of such a system in Brisbane’s climate zone requires careful design, proper selection of components, and a cheap heat source for regeneration. The paper also discusses the economy-cycle options for this system in such a climate and compares its effectiveness to natural ventilation.

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