地热农副产品干燥装置的设计和中间试验

A Study on Designing and Manufacturing a Set of Intermediate Testing Equipment for Drying Agricultural Products with Geothermal Energy

本文根据干燥过程的理论分析和试验研究结果,提出了热风式干燥器设计参数的选择原则,给出一套有一定参考价值的干燥系统的计算方法。该方法概念清楚,不必计算废气排热损失,简化了计算过程。依此,我们设计制造了一套地热干燥中间试验装置,它利用60～70℃的地热水作热源,一次可投湿物料200kg,对于像白菜这类初含水率在90％以上的物料,其每小时最大干燥脱水量超过30kg,平均热效率达到53％。试验结果表明:只有当物料的含水率在90％以上,且表面结合水多的情况下,实际过程才会出现等速干燥阶段。

According to drying theory and experimental results, the paper has given the principle how to determine original design parameters for hot air type drier. The method of thermodynamic calculation for the drier has also been given. This method needn't to calculate the exhaust thermal loss. Thus, it makes the calculatin process to be simplified. According to this design idea, a set of intermediate testing hot air type drying equipment has been designed and manufactured. The thermal source of the equipment is 60- 70℃ geothermal water. The drier has a batch capacity of 200kg raw material. The maximum drying rate is above 30kgw / h when moisture content of the raw material is higher than 90% and the average thermal efficiency of 53% has been obtained in the whole drying period.The result of drying experiment indicated that in practical process, drying constant-rate period exists only in the condition that the moisture content of raw material is higher than 90% and a great deal of surface combined-moisture exists.