Numerical study on recovering moisture and heat from flue gas by means of a macroporous ceramic membrane module

Energy ◽  
2020 ◽  
Vol 207 ◽  
pp. 118230 ◽  
Author(s):  
Jialei Zhang ◽  
Zhaohao Li ◽  
Heng Zhang ◽  
Haiping Chen ◽  
Dan Gao
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

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.


2021 ◽  
Vol 407 ◽  
pp. 22-30
Author(s):  
Guilherme Luiz Oliveira Neto ◽  
Nívea Gomes Nascimento de Oliveira ◽  
Francisco Alves Batista ◽  
Gustavo Henrique de Almeida Barbalho ◽  
Anderson Melchiades Vasconcelos da Silva ◽  
...  

Environmental concern has encouraged development related to polluted water treatment. Produced water originated from oil exploration has been submitted to different separation processes such as settling tanks, floaters, two-phase and three-phase separators, hydrocyclones, and membranes. On the use of membranes, the goal is to separate soluble components from solutions based on the size, charge, shape, and molecular interactions between the solute and membrane surface. In the present work, a numerical study was developed on the oil-water mixture separation process using a porous ceramic membrane module. The mathematical model used in this research is composed of mass and momentum conservation equations coupled to Darcy ́s law and SST k-ω turbulence model. Simulations were carried out employing the Ansys CFX commercial software. Results of the pressure, velocity, oil concentration distribution inside the device and membrane are presented and discussed. The results showed that the geometric aspects of the proposed microfiltration module and the membrane distribution within the separation module had a significant influence on the hydrodynamic flow leading to polarized layer dispersion.


Author(s):  
Elizaveta Ivanova ◽  
Berthold Noll ◽  
Peter Griebel ◽  
Manfred Aigner ◽  
Khawar Syed

Turbulent mixing and autoignition of H2-rich fuels at relevant reheat combustor operating conditions are investigated in the present numerical study. The flow configuration under consideration is a fuel jet perpendicularly injected into a crossflow of hot flue gas (T > 1000K, p = 15bar). Based on the results of the experimental study for the same flow configuration and operating conditions two different fuel blends are chosen for the numerical simulations. The first fuel blend is a H2/natural gas/N2 mixture at which no autoignition events were observed in the experiments. The second fuel blend is a H2/N2 mixture at which autoignition in the mixing section occurred. First, the non-reacting flow simulations are performed for the H2/natural gas/N2 mixture in order to compare the accuracy of different turbulence modeling methods. Here the steady-state Reynolds-averaged Navier-Stokes (RANS) as well as the unsteady scale-adaptive simulation (SAS) turbulence modeling methods are applied. The velocity fields obtained in both simulations are directly validated against experimental data. The SAS method shows better agreement with the experimental results. In the second part of the present work the autoignition of the H2/N2 mixture is numerically studied using the 9-species 21-steps reaction mechanism of O’Conaire et al. [1]. As in the reference experiments, autoignition can be observed in the simulations. Influences of the turbulence modeling as well as of the hot flue gas temperature are investigated. The onset and the propagation of the ignition kernels are studied based on the SAS modeling results. The obtained numerical results are discussed and compared with data from experimental autoignition studies.


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