Method of dehumidifying and drying powdered or granular material and system for dehumidifying and drying powdered or granular material

摘要

A system for dehumidifying and drying a powdered or granular material having a drying hopper, a dehumidifying unit, and a circulation route having a processing gas supply route and a processing gas dehumidifying route that interconnect the drying hopper and the dehumidifying unit to allow processing gas to circulate is proposed. The system repeatedly supplies and circulates the processing gas in the circulation route. The processing gas supply route and the processing gas dehumidifying route are interconnected by a bypass route having a regulation valve. A temperature sensor for detecting the temperature of processing gas exhausted from the drying hopper is installed in the processing gas dehumidifying route. The system further has a control means for controlling opening or closing of the regulation valve, provided in the bypass route, based on a temperature detection signal detected by the temperature sensor. The control by the control means is performed under the condition that the total circulation amount of the processing gas circulated in the circulation route, including the amount of the gas passing through the bypass route, is held substantially constant.

主权项

1. A method of dehumidifying and drying powdered or granular material using a system for dehumidifying and drying powdered or granular material, said system comprising a drying hopper for storing therein and drying a powdered or granular material, a dehumidifying unit equipped with an absorbing body therein, and a circulation route having a processing gas supply route and a processing gas dehumidifying route that interconnect said drying hopper and said dehumidifying unit, a processing gas being repeatedly circulated for dehumidifying and drying by being returned to said dehumidifying unit from said drying hopper via the processing gas dehumidifying route after being heated by a heater and allowed to pass through said drying hopper,
said processing gas supply route being configured to connect a downstream side of said absorbing body of said dehumidifying unit and an upstream side of said heater of said drying hopper such that processing gas dehumidified and processed by said dehumidifying unit is supplied toward said drying hopper; said processing gas dehumidifying route being configured to connect a downstream side of said drying hopper and an upstream side of the absorbing body of said dehumidifying unit such that gas passing through said drying hopper is supplied toward said dehumidifying unit; said method comprising the following process: a dehumidifying process in which the processing gas exhausted from said drying hopper is dehumidified with said absorbing body in said dehumidifying unit by allowing the processing gas to pass through said absorbing body; a heating regenerating process in which a heating gas is allowed to pass through said absorbing body for its own reuse after said dehumidifying process; and a cooling regenerating process in which a cooling gas is allowed to pass through said absorbing body for its own reuse after said heating regenerating process; whereby the flow amount of the processing gas to pass through a bypass route, which interconnects midway of the processing gas supply route and midway of the processing gas dehumidifying route and supplies a part of dehumidified processing gas supplied to said heater and said drying hopper through said processing gas supply route without passing through said heater and said drying hopper, is adjusted depending on the temperature of the processing gas exhausted from said drying hopper under the condition that the total circulation amount of the processing gas circulating in said circulation route, including the amount of the gas passing through the bypass route, is substantially kept a predetermined amount, and thereby performing control of increasing or decreasing the flow amount of the processing gas to supply to said drying hopper.