Experimental Study Of Direct Contact Condensation In Structured Packing

Direct contact condenser is widely used with the continuous development of thepetrochemical and power generation industry. Structured packings are more efficientin mass and heat transfer, and have lower energy consumption and pressure drop.However, due to the complex flow patterns of the vapor-liquid, the condensationprocess is extremely complex, and research on direct contact condensation (DCC) instructured packing is slower than industrial applications.In order to systematically study the factors influencing the process and extendthe database of DCC, this paper will experimentally evaluate the steam-water-aircondensation in Tupac125Y structured packing under atmospheric and vacuumpressure. Vapor load, liquid spray density, liquid temperature, non-condensable gasand operating pressure were analyzed.The results showed that with steam-water condensation, liquid temperature has agreat impact on condensation rate; when operated under vacuum pressure, the steamcondensation efficiency is higher than under atmospheric pressure; the increase ofliquid spray density will strenthen the heat and mass transfer and the influence rulesof vapor flow rate on the condensation is not obvious. When air was injected to thecolumn, it can be found that the packing height required for condensation is increasedand the main condensation zone also moves up; the impact of liquid temperature oncondensation rate went down; the liquid spray density affected the temperaturedistribution. Besides, with the packing height required for condensation and with theincrease of vapor and noncondensable gas flow rate, the packing height required forcondensation also increases.The Delft model was used to simplify the flow pattern of the two phases instructured packing, a heat balance model was established to calculate the localvolumetric heat transfer coefficient in the packing. Dimensionless numbers were usedto represent the operating parameters and correlate the heat transfer coefficient. Theempirical correlations based on dimensionless numbers have been verified by variousexperimental measurements and can give some helpful guidance in the design andoperation of direct contact condensers with structured packings.