Entropy generation analysis of heat and water recovery from flue gas by transport membrane condenser

Energy ◽  
2019 ◽  
Vol 174 ◽  
pp. 835-847 ◽  
Author(s):  
Liehui Xiao ◽  
Minlin Yang ◽  
Shuaifei Zhao ◽  
Wu-Zhi Yuan ◽  
Si-Min Huang
Author(s):  
Kuifang Wan ◽  
Yunhan Xiao ◽  
Shijie Zhang

By adding an induced draft fan or exhaust compressor between flue gas condenser and stack to make the turbine expand to a pressure much lower than ambient pressure, this paper actually employed inverted Brayton cycle to solve stack temperature problems after water recovery from Humid Air Turbine (HAT) cycle exhaust gas and compare the effect of different discharging methods on the system’s performance. Comparing with the methods of gas discharged directly or recuperated, this scenario can obtain the highest electrical efficiency under certain pressure ratio and turbine inlet temperature. Due to the introduction of induced draft fan, in spite of one intercooler, there are twice intercoolings during the whole compression since the flue gas condenser is equivalent to an intercooler but without additional pressure loss. So the compression work decreases. In addition, the working pressure of humidifier and its outlet water temperature are lowered for certain total pressure ratio to recover more exhaust heat. These enhance the electrical efficiency altogether. Calculation results show that the electrical efficiency is about 49% when the pressure ratio of the induced draft fan is 1.3∼1.5 and 1.5 percentage points higher than that of HAT with exhaust gas recuperated. The specific works among different discharging methods are very closely. However, water recovery is some extent difficult for HAT employing inverted Brayton cycle.


2017 ◽  
Vol 110 ◽  
pp. 686-694 ◽  
Author(s):  
Haiping Chen ◽  
Yanan Zhou ◽  
Sutian Cao ◽  
Xiang Li ◽  
Xin Su ◽  
...  

2017 ◽  
Vol 113 ◽  
pp. 843-850 ◽  
Author(s):  
Shuaifei Zhao ◽  
Shuiping Yan ◽  
David K. Wang ◽  
Yibin Wei ◽  
Hong Qi ◽  
...  

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).


Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 701
Author(s):  
Da Teng ◽  
Liansuo An ◽  
Guoqing Shen ◽  
Shiping Zhang ◽  
Heng Zhang

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.


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