旋梯式螺旋折流板换热器预热水煤浆的流动与换热性能

Preheat of coal water slurry (CWS) before it entering gasifier can improve gasification efficiency and reduce oxygen consumption. Shell-and-tube heat exchangers with ladder-type fold baffles were proposed to preheat CWS which flows through the shell side, while conductive oil flows through the tube side as the hot fluid. Based on the experimental study, the feasibility of preheating CWS in the shell side of heat exchangers, and effects of conductive oil reference temperature and CWS flow rate on flow and heat transfer performance were studied. Empirical correlations of Nu_s and f_s were obtained. The experimental results show that it is completely feasible to preheat CWS in the shell side of heat exchangers. Increasing the conductive oil reference temperature can increase the temperature difference of CWS and the overall heat transfer coefficient, while the shell side pressure drop is decreased. Increasing the CWS flow rate can increase the overall heat transfer coefficient, but higher shell side pressure drop is obtained. The research results provide guidelines for further study of CWS preheating equipment and are beneficial for working condition selection of CWS preheating.