Technology for preparing dipotassium phosphate through spray-drying method

Abstract

The invention provides a technology for preparing dipotassium phosphate through a spray-drying method. The technology comprises the following steps: (1) carrying out neutralization reaction on potassium hydroxide and phosphoric acid in a reaction kettle; controlling the pH (Potential of Hydrogen) value of a finishing point of the reaction; (2) after concentrating a reaction solution obtained by step (1), conveying the reaction solution into a drying tower and carrying out spray-drying; (3) conveying clean air into a heat exchanger through an air blower, and carrying out heat exchange with hotair of a heating furnace; (4) conveying hot air of the drying tower and enabling the hot air to be in sufficient contact with a spraying material, so as to evaporate water instantly; enabling a solidproduct to fall down to a tower bottom in a powder form, and conveying through a conveying machine and packaging; (5) discharging and conveying the hot air in a spray-drying tower to a concentration kettle by an induced draft fan through a tail hot air outlet, and heating a concentrated material through tail air; conveying the concentrated material into the spray-drying tower; recycling residual liquid and emptying tail gas to realize energy recycling. The technology provided by the invention has the beneficial effects that the hot air exhausted by the drying tower is introduced into the concentration kettle to heat a concentrated reaction solution, so that 1 / 3 of coal resources are saved, the heat utilization rate is improved and the environment pollution is reduced.

Description

technical field [0001] In the technical field of chemical engineering, the invention specifically relates to a process for preparing dipotassium hydrogen phosphate by a spray drying method. Background technique [0002] Dipotassium hydrogen phosphate is a basic chemical raw material, which is widely used in food, building materials, agriculture, medicine and other industries. The current domestic output is about 300,000 tons per year. There are two kinds of dipotassium hydrogen phosphate, namely dipotassium hydrogen phosphate trihydrate (K 2 HPO 4 ·3H 2 O) and anhydrous dipotassium hydrogen phosphate (K 2 HPO 4 ), because the former will increase the transportation cost and bring three crystal waters (3H 2 O), the use is limited, so the market is dominated by anhydrous dipotassium hydrogen phosphate, accounting for about 2 / 3 of the total; because dipotassium hydrogen phosphate is very soluble in water and has a strong ability to combine with water, the efficient product...

AI Technical Summary

Problems solved by technology

There are two kinds of dipotassium hydrogen phosphate, namely dipotassium hydrogen phosphate trihydrate (K 2 HPO 4 ·3H 2 O) and anhydrous dipotassium hydrogen phosphate (K 2 HPO 4 ), because the former will increase the transportation cost and bring three crystal waters (3H 2 O), the use is limited, so the market is dominated by anhydrous dipotassium hydrogen phosphate, accounting for about 2 / 3 of the total; because dipotassium hydrogen phosphate is very soluble in water and has a strong ability to combine with water, the efficient production method is Spray drying method, in this process, in order to ensure that the product does not agglomerate, the moisture content is required to be controlled within 0.5%. To meet this requirement, the hot air discharged by the induced draft fan must reach 170-180°C, and the hot air is directly discharged into the air. thereby wasting energy

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