A kind of method of film crystallization refining coking crude ammonium sulfate

A crude ammonium sulfate and crystallization technology, applied in the direction of ammonium sulfate, can solve the problems of uneven supersaturation, uneven crystal particle size, etc., achieve the effect of improving color grade and purity, and reducing energy consumption

CN103708501BActive Publication Date: 2017-08-25武汉科技大学资产经营有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-08-25
Patent Text Reader

Abstract

The invention relates to a method for refining coking crude ammonium sulfate by membrane crystallization. The technical solution is: the pretreated coking crude ammonium sulfate crystallization mother liquor is fed into the membrane module, and the water in the mother liquor passes through the membrane in the form of water vapor through membrane distillation and is condensed into liquid water on the other side of the membrane, leaving The crystallization mother liquor of the membrane module is concentrated to supersaturation and then sent to the crystallizer, the crystals are fluidized and suspended in the circulating crystallization mother liquor, the crystallization mother liquor on the upper layer of the crystallizer is pumped into the membrane module for internal circulation, and the crystallization product is drawn out from the lower part of the crystallizer. Solid-liquid separation and drying to obtain ammonium sulfate crystals. The present invention uses membrane distillation to evaporate and concentrate the ammonium sulfate crystallization mother liquor to achieve supersaturation, and the crystal growth is located in the fluidized bed crystallizer, which provides better conditions for crystal growth, and the fluidized bed crystallizer has both particle size classification, so that the growth The ammonium sulfate crystal product has a large and uniform particle size. The invention can also effectively reduce the production cost of ammonium sulfate recrystallization and refinement.
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Description

technical field

[0001] The invention belongs to the technical field of metallurgy, coking and chemical industry, and in particular relates to a method for refining coking crude ammonium sulfate by membrane crystallization. Background technique

[0002] Coking ammonium sulfate is a large industrial by-product of coke oven gas purification. my country's coke output ranks first in the world, and the domestic coking ammonium sulfate output is huge. Ammonium sulfate is an important nitrogen fertilizer, and it can also be used as a printing and dyeing agent, a food catalyst, and a leather deliming agent in industry.

[0003] Domestic coking ammonium sulfate is mostly produced by the saturator method. Because of the influence of impurities, it is often gray, green, blue, dark black or red. The particle size does not exceed 0.5mm; and the moisture and acidity exceed the standard. Ammonium sulfate crystals are easy to absorb moisture and agglomerate, especially when the air humidi...

Examples

Embodiment 1

[0019] A method for refining coking crude ammonium sulfate by film crystallization, the specific steps are:

[0020] Step 1. Under the conditions of normal pressure, 40~80°C and 300~500r / min rotation speed, first prepare a coking crude ammonium sulfate aqueous solution with a concentration of 40~50wt%; then use NaOH to adjust the pH of the coking crude ammonium sulfate solution to 7~ 9; then add activated carbon accounting for 1~5wt% of coking crude ammonium sulfate to the aqueous solution of coking crude ammonium sulfate, keep stirring for 0.5~1h, then heat-preserve and filter, add an acid regulator to the filtrate to make it pH=5~7, and obtain coking Crude ammonium sulfate crystallization mother liquor;

[0021] Step 2. Send the coking crude ammonium sulfate crystallization mother liquor prepared in step 1 into the membrane module. The water in the mother liquor passes through the membrane in the form of water vapor through membrane distillation and is condensed into liquid ...

Embodiment 2

[0026] A method for refining coking crude ammonium sulfate by film crystallization, the specific steps are:

[0027] Present embodiment is except that described acid regulator is phosphoric acid, all the other are with embodiment 1.

Embodiment 3

[0029] A method for refining coking crude ammonium sulfate by film crystallization, the specific steps are:

[0030] Present embodiment is except that described acid regulator is citric acid, all the other are with embodiment 1.