Improving heat transfer and water recovery performance in high‐moisture flue gas condensation using silicon carbide membranes

Author(s):  
Chao Ji ◽  
Li Li ◽  
Hong Qi
2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Haiping Chen ◽  
Xiangsheng Li ◽  
Jiadi Wei ◽  
Yijun Feng ◽  
Dan Gao

In this paper, the manufacturing process of microceramic membrane is summarized. The main material of this membrane is fly ash which can reduce the sintering temperature and save the costs. The coal ash ceramic membrane (CACM) was characterized by XRD, SEM, and mercury intrusion method. The results show that the mullite phase formed by CACM at the sintering temperature of 1250°C has morphology and structural characteristics similar to the commercial microceramic membrane. The membrane surface is uniform and dense, without cracks; the pore diameter is 1–4 μm, and the porosity is 26.6%. Furthermore, the CACM and CMCM were compared at the aspects of water and heat recovery performance using flue gas. The experiment indicated that when the flue gas temperature was 50–85°C, the water recovery performance of these two kinds of membrane was similar. Also, the heat transfer capability of the coal ash ceramic membrane was close to that of the commercial microceramic membrane when the temperature range of flue gas was controlled between 50°C and 70°C. When the temperature of flue gas reaches 80°C, the heat transfer performance of the commercial ceramic membrane is better, and the difference of heat recovery between these two kinds of membranes is 19.3%. In general, the CACM and CMCM have similar mass transfer performance, and the heat transfer efficiency of CACM is lower than that of CMCM, but the costs of CACM is much lower than that of CMCM which has a good research prospect in the future.


2019 ◽  
Vol 160 ◽  
pp. 114060 ◽  
Author(s):  
Zhaohao Li ◽  
Heng Zhang ◽  
Haiping Chen ◽  
Jialei Zhang ◽  
Chao Cheng

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2743-2756
Author(s):  
Guifeng Gao ◽  
Fei Wang ◽  
Yongzhang Cui

A stainless steel corrugated fins and flat-tube heat exchanger is designed, which has a plate-fin structure. To optimize the structural parameters of this exchanger, including corrugation angle, corrugation pitch and fin length, 3-D simulation model and test were proposed. The numerical results indicated that the corrugation angle significantly affects both on heat transfer performance and pressure drop. The fin with angle, A = 0~20?, have demonstrated the higher heat transfer efficiency, lesser gas condensation, lower pressure drop, higher outlet flue gas temperature in low T region, and no exceeding the distortion temperature in high T region. Corrugation pitch and fin length influence thermal and hydraulic characteristics, outlet flue gas temperature, and fin temperature. To improve heat transfer performance, and reduce the fin temperature in high T region and ease gas condensation in low T region, smaller corrugation pitch and shorter fin length were recommended in the low T region, whereas higher values were more reasonable in high T region. Noticeably, the heat transfer and flow characteristics were better in the high T region than the low T region. Therefore, higher priority should be given to the structural optimization in the high T region in order to in-crease the heat transfer enhancement


Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 844
Author(s):  
Robertas Poškas ◽  
Arūnas Sirvydas ◽  
Vladislavas Kulkovas ◽  
Povilas Poškas

Waste heat recovery from flue gas based on water vapor condensation is an important issue as the waste heat recovery significantly increases the efficiency of the thermal power units. General principles for designing of this type of heat exchangers are known rather well; however, investigations of the local characteristics necessary for the optimization of those heat exchangers are very limited. Investigations of water vapor condensation from biofuel flue gas in the model of a vertical condensing heat exchanger were performed without and with water injection into a calorimetric tube. During the base-case investigations, no water was injected into the calorimetric tube. The results showed that the humidity and the temperature of inlet flue gas have a significant effect on the local and average heat transfer. For some regimes, the initial part of the condensing heat exchanger was not effective in terms of heat transfer because there the flue gas was cooled by convection until its temperature reached the dew point temperature. The results also showed that, at higher Reynolds numbers, there was an increase in the length of the convection prevailing region. After that region, a sudden increase was observed in heat transfer due to water vapor condensation.


Sign in / Sign up

Export Citation Format

Share Document