A digestive system utilizing waste heat and its temperature control method

Abstract

The invention discloses a digestion system utilizing waste heat and a temperature control method thereof. The digestion system comprises a heat exchanger, a hot water storage tank, a digestion slot, a first temperature control solenoid valve, a first temperature sensor and a first PID (proportion integration differentiation) controller, wherein the heat exchanger is used for heating cold water by utilizing waste heat; the hot water storage tank is connected with a hot water outlet of the heat exchanger, and is used for storing heat-exchanged hot water; the digestion slot is connected with the outlet of the hot water storage tank and used for receiving hot water and digesting lime; the first temperature control solenoid valve is connected at a cold water inlet of the heat exchanger; the first temperature sensor is used for sensing a temperature signal at a hot water inlet of the hot water storage tank; and the first PID controller is connected with the first temperature control solenoid valve and the first temperature controller, and used for receiving a temperature signal of the first temperature sensor and regulating flow opening of the first temperature control solenoid valve to regulate water amount of cold water which enters the heat exchanger. The digestion system is used for recycling tail gas waste heat and keeping the stability of the hot water storage tank and a digestion temperature by virtue of intelligent regulation to guarantee that the waste heat is utilized to the greatest extent, and the digestion quality is improved.

Description

technical field [0001] The invention relates to a digestion system utilizing waste heat and a temperature control method thereof. Background technique [0002] At present, lime digestion is required in the production process of nano-calcium carbonate. Traditional lime digestion basically uses tap water or production water for digestion, which not only takes a long time to digest, but also results in coarse particles of milk of lime (calcium hydroxide) and poor activity due to low digestion temperature. Inadequacies. Existing lime digestion adopts a heating digestion device to achieve the characteristics of fine lime particles, low slag content and good activity. For example, Chinese patent application CN103011627A discloses a lime digestion device, which includes a pool type digestion tank or a rotary drum digestion device. machine, and the steam pipe that feeds steam into it. On one side of the steam pipe, there is an opening for conveying lime into the steam pipe. It uses...

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Problems solved by technology

[0002] At present, lime digestion is required in the production process of nano-calcium carbonate. Traditional lime digestion basically uses tap water or production water for digestion, which not only takes a long time to digest, but also results in coarse particles of milk of lime (calcium hydroxide) and poor activity due to low digestion temperature. Inadequacies

Existing lime digestion adopts a heating digestion device to achieve the characteristics of fine lime particles, low slag content and good activity. For example, Chinese patent application CN103011627A discloses a lime digestion device, which includes a pool type digestion tank or a rotary drum digestion device. machine, and the steam pipe that feeds steam into it. On one side of the steam pipe, there is an opening for conveying lime into the steam pipe. It uses steam to pre-digest the lime. The digestion temperature is always kept above 100°C. The lime activity is high and the reaction speed is high. fast, and then enter the pool-type digester or drum digester to complete the final digestion. Although the digested milk of lime has better performance, it uses steam for pre-digestion, which not only increases the production cost virtually, but also is not conducive to energy saving and environmental protection.

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