Method for producing industrial excellent ammonium sulfate through coarse ammonium sulfate coking coupling evaporation solventing-out crystallization

Abstract

The invention relates to a method for producing industrial excellent ammonium sulfate through coarse ammonium sulfate coking coupling evaporation solventing-out crystallization. According to the technical scheme, the pH of a coking coarse ammonium sulfate water solution is adjusted through NaOH at first, activated carbon is added in the water solution, the water solution is filtered and a coking coarse ammonium sulfate crystallization mother solution is prepared; an acidity regulator, a crystal character modifier and a seed crystal are added in the mother solution, the crystal is cultivated, and suspended crystal pulp is prepared; finally, evaporation crystallization is conducted when a soluble analysis agent is added in the suspended crystal pulp, filtering and drying are conducted and an ammonium sulfate crystal is prepared; the crystal product is concentrated in particle size distribution, smooth in surface, high in purity and good in flowing performance, and can reach industrial excellent product specifications. The particle size and the addition of the seed crystal are changed, and the average particle size and particle size distribution of an ammonium sulfate crystal product are regulated and controlled. The method for producing the industrial excellent ammonium sulfate through coarse ammonium sulfate coking coupling evaporation solventing-out crystallization has the advantages of being low in production cost, short in production period, controllable in average particle size, concentrated in particle size distribution, high in one-way crystallization yield (larger than or equal to 95 %), and high in product quality.

Description

technical field [0001] The invention belongs to the technical field of industrial crystallization, and in particular relates to a method for producing high-quality industrial ammonium sulfate by coupling coking crude ammonium sulfate with evaporation, dissolution, and crystallization. Background technique [0002] Coking ammonium sulfate is a large industrial by-product of coke oven gas purification. A JN60-60 type 2×65 hole 7m 63 coke oven with an annual output of 2 million tons of coke can reach 30,000 t / a of ammonium sulfate. Since 1993, my country's coke output has been ranked first in the world, and it exceeded 400 million tons in 2011, so the output of domestic coking ammonium sulfate is huge. Ammonium sulfate is an important nitrogen fertilizer, and it can also be used as printing and dyeing agent, food catalyst, buffering agent, leather deliming agent and so on in industry. [0003] At present, most coking plants in China use the saturator method to produce ammoniu...

AI Technical Summary

Problems solved by technology

However, regardless of evaporative crystallization or cooling crystallization, crystal scale is easy to form on heat exchange surfaces such as coils or jackets, which significantly reduces heat transfer efficiency, makes it difficult to control the evaporation rate or cooling rate, and prolongs the crystallization time, resulting in a particle size distribution of crystallized products. Inhomogeneity, low production efficiency

Moreover, for the evaporative crystallization process, the solid-liquid suspension density in the crystallizer is getting higher and higher, the crystal-liquid mixing is uneven, the crystal is easy to sink to the bottom, and the friction and collision between the crystals and between the crystal and the stirring paddle causes the crystal to break during the crystallization process. Seriously, this will also aggravate the uneven particle size distribution of crystallized products

In addition, ammonium sulfate has a high solubility in water (0°C, 70g / 100g water). Regardless of evaporation crystallization or cooling crystallization, there will still be a large amount of uncrystallized ammonium sulfate in the mother liquor at the end of crystallization, resulting in low production capacity per unit volume crystallizer.

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