三相生物流化床膨胀特性方程的研究

Study on the Formula of Expansion Characteristic of Three phase Biological Fluidized Bed.

研究建立了描写三相生物流化床床层膨胀特性的经验关联式．当已知床内表观液速、表观气速和载体上生物膜厚度时，能比较准确地预测床层膨胀高度，为设计提供依据．与以往不同的是，本研究通过等效函数的设置和求解，用一个方程将两相床和三相床的膨胀特性描述出来．该方程能反映三相床低气速下的床层收缩行为，在气速为零时可还原为两相床．试验用反应器直径１．４ｍ，高６．５ｍ，载体为０．３—０．５ｍｍ的石英砂，射流曝气体内充氧．４种生物膜厚：５２，８０，１１５，１３７μｍ．试验用生活污水ＢＯＤ５４７．６—７７．２ｍｇ／Ｌ．

The formula of expansion characteristic in the three phase biological fluidized bed has been founded in this study. When the empty bed velocity of liquid and gas as well as the thickness of bio film are known,the high of bed expansion is determined rather precisely,which provided basis for design. It is unusual that the expand ruler in both the two phase bed and three phase fluidized bed are reflected by using one equivalent function; the relationship of the dynamic in biochemical reaction and behavior of hydomechanics has been set up by the thickness of bio film. The behavior of shrink in bed under the low velocity of gas can be reflected by this formula,and the formula in three phase bed can be restored to one in two phase bed when the velocity of gas is zero. The tested bed is 1.4m of diameter and 6 5m of high,in which the diameter of midia made of quartz sand is 0.3—0.5mm, using air jet for aeration inside the reactor. The test is within the bio film thickness of 52,80,115,137m, respectively. The BOD 5 concentration in the sewage tested are 47.6 77.2mg/L.