CONTROL METHOD OF GRAIN DRYING AND STORAGE PROCESSES Russian patent published in 2014 - IPC F26B25/22 F26B3/14 

FIELD: heating.

SUBSTANCE: control method of grain drying and storage processes provides for pre-heating of wet grain with a waste drying agent and further cleaning of the drying agent from light impurities in a cyclone, its drying and cooling in an evaporator of a heat pump unit, the working and reserve sections of which are alternatively changed over from a condensation mode to a regeneration mode; drying, cooling and separation of the drying agent into two flows, one of which is supplied for drying through a condenser of the heat pump in a closed loop mode with make-up of a fresh drying agent, and the other one for active grain ventilation to silos; measurement of flow rate, temperature and moisture content of the drying agent before drying and active ventilation of grain with influence on power of the compressor drive as to flow rate, temperature and humidity of grain supplied for drying, and additionally, it is characterised by the fact that grain drying is performed in two series located zones of a shaft grain drier and a cooling zone. With that, for heating and cooling of the drying agent there used is a vapour compression two-stage heat pump, a cold drying agent is supplied by means of fans via two flows, one of which is supplied to the condenser of the second stage of the heat pump, and the other one is supplied for grain cooling; with that, for temperature stabilisation in zone I of the grain drier there supplied is a mixture of hot and cold drying agents; with that, some part of hot drying agent after condenser of stage II is discharged for unfreezing of the evaporation section operating in the regeneration mode, with return for drying before the condenser of stage II in the closed loop mode, hot drying agent is supplied to zone II of the grain drier, and cold drying agent is supplied to the cooling zone; as per the grain consumption at the grain drier inlet there set is flow rate of drying agent in drying zones and the cooling zone; as per temperature of the drying agent at the inlet of zone II of the drier there adjusted is the drive power of the compressor of the second stage; as per temperature of the drying agent in zone I of the drier there defined is ratio of hot and cold drying agent flow rates; at deviation of heat transfer coefficient k on cooling surface of the working section of the evaporator of the first stage between the waste drying agent and the cooling agent from the specified interval of values decreasingly, the working section is changed over from the condensation mode to the regeneration mode and regeneration of cooling surface is performed by hot drying agent. Losses of the drying agent are compensated prior to drying by increasing the flow rate of the fresh drying agent in a make-up line.

EFFECT: method allows reducing power consumption and improving quality of dried grain.

2 tbl, 1 dwg