热管联合多级串联热泵玉米干燥系统性能试验

中国东北地区现有的粮食干燥系统多为大型多段塔式燃煤干燥系统,在粮食干燥过程中,热空气与粮食经过一次换热后,生成的高温高湿废气直接排入了大气,不仅造成了能量的巨大浪费,而且严重污染了环境。该文针对东北地区寒冷气候特点及多段塔式燃煤玉米干燥系统存在的高能耗、高污染问题,开发了一种热管联合多级串联热泵玉米干燥系统,该系统能够实现对多段塔式燃煤玉米干燥中废气的余热回收和废气中杂质的清洁处理,从而达到节能减排的效果。在该系统的基础上研制了50、150和300 t/d的系列化玉米热泵干燥装备,进行了3种规模的产业化示范,并对300 t/d的玉米热泵干燥系统进行了性能试验。结果表明,系统每小时的耗电量为538 kW·h,除湿速率为2016 kg/h,热泵机组的制热系数COP(coefficient of performance,COP)在3.7~6.7之间,除湿能耗比SMER(specific moisture extraction rate,SMER)为3.75 kg/(kW·h)。对多段塔式玉米热泵干燥和玉米燃煤干燥经济性进行比较研究,结果表明:得到1 kg干玉米的热泵干燥成本为0.038元,而燃煤干燥的成本为0.049元,单位玉米的热泵干燥成本比燃煤干燥成本降低22.4%。与玉米燃煤干燥相比,玉米热泵干燥能大量降低污染物的排放,节能减排效果明显,可为热泵干燥技术在粮食烘干领域应用提供有价值的参考。

Experiment on performance of corn drying system with combination of heat pipe and multi-stage series heat pump equipment

Abstract: Most of the existing grain drying systems in the northeast of China are large and multistage tower-type coal drying systems, and in the process of grain drying, the system produces hot and humid exhaust gases directly into the atmosphere after a heat exchange of hot air and grain. It not only caused great waste of energy, but also seriously polluted the environment. Aiming at the characteristics of cold climate in northeast China and the problems of high energy consumption and high pollution of coal-fired corn drying system of the multi-stage tower type, a heat pipe combined with corn drying technology of multistage series heat pump is developed. This technology can realize the recovery of waste heat and exhaust impurities in the corn drying by burning coal in multistage tower-type, so as to achieve the effect of energy saving and emission reduction. On the basis of this technology, the series of 50 t/d, 150 t/d and 300 t/d of corn heat pump drying equipment are developed, and the industrialization demonstration of 3 kinds of scale has been carried out. The performance testing of 300 t/d corn heat pump drying system is carried out.. The results show that the power consumption of per hour is 538 kW. h, the dehumidification rate is 2016 kg/h, the heating coefficient COP of the heat pump is between 3.7-6.7, and the energy consumption ratio SMER of dehumidification is 3.75 kg/(kW·h). In the end , the economy between the heat pump drying of corn and the drying of corn by burning coal of the multi-stage tower are compared .The results show that cost of the heat pump drying to get one kilogram of dry corn is 0.038 yuan, while the cost of coal-fired drying is 0.049 yuan. The cost of heat pump drying of per unit of corn is 22.4% lower than the cost of the coal-fired drying. Compared with the drying of corn by coal, the heat pump drying of corn can greatly reduce pollutant emissions, and the effect of energy saving and emission reduction is obvious, which provides a valuable reference for the application of heat pump drying technology in the field of grain drying.