Ammonium sulfate production for a variety of reasons will appear color changes, to solve the problem of ammonium sulfate discoloration needs of various aspects of analysis, to take effective measures.
I plant is the use of spray saturator production of ammonium sulfate process. I plant since the production has been found that ammonium sulfate appeared black, gray and other different colors, Ammonium Sulfate to produce the quality of substandard products. Some experience is summarized in the process of problem solving.
Under normal circumstances, the pure state of ammonium sulfate is colorless long diamond-shaped crystals, the density of 1766kg / m³. Molecular weight of 132.15, excellent ammonium sulfate content of ≥ 21%, due to the impact of impurities often with gray or dark black and other different colors. Crystalline mostly needle-like, flaky or powder-like, the formation of small particles, nitrogen content decreased. There are many factors that affect the quality of ammonium sulfate, such as: sulfuric acid concentration, mother liquor temperature, Ammonium Sulfate saturator resistance and so on.
Ammonium sulfate color black or gray
The reason for the blackening of ammonium sulfate is mainly due to the following aspects: the failure of the electric trapping device, in addition to the tar effect is not good; raw ammonia water containing large amount of tar, resulting in the process of ammonia tar with ammonia into the ammonium sulfate system; Ammonium Sulfate The quality of sulfuric acid is not good; the mother liquor tank is evacuated and the floating acid tar is pumped into the saturator.
The problems identified and the measures taken
(1) Under normal circumstances is due to the drum cooling section of the electric pump to catch the failure, electric tar in the tar content exceeded. At this time the ammonium sulfate particles will be observed with significant impurities. Due to excessive tar content, a large amount of tar into the mother liquor of ammonium sulfate, and the mother liquor in the reaction of acid to form a large number of acid tar, in the big mother liquor pump under the action of a large number of acid tar and ammonium sulfate mother liquor mixed with ammonium sulfate mother liquor color Also become black, ammonium sulfate mother liquor black is generally affected by the tar. At this time I plant to take the measures are: as soon as possible to return to the normal work of electric arrest, Ammonium Sulfate the appropriate increase in electric catch voltage, to strengthen the frequency of rinse electric catch, from January to 1 month to 1; increase full flow tank fishing acid tar times, From 1 hour 1 to half an hour.
(2) the remaining ammonia tank more tar, tar with ammonia into the steam tower, into the saturator of the ammonia entrainment of impurities, water vapor increased, combined with the crystal ratio, so that the color of ammonium sulfate ash, black, I plant to take Measures are: the steam ammonia tower to saturator ammonia pipe water seal to clean up, reduce the ammonia in the condensate (tar and other impurities) into the saturator; the top of the steam tower top subdivision heat exchanger area increased, timely The ammonia in the entrained impurities condensed down to reduce the impurities in the ammonia; control ammonia ammonia residual oil, to strengthen the remaining ammonia tank put the tar work every 2 hours put 1, to minimize the remaining ammonia in the tar content.
(3) The main impurities in the mother liquor in the saturator are iron salts, aluminum salts, thiocyanates, various arsenic compounds and various organic compounds such as phenol, pyridine, naphthalene and various components of tar. The impurity in the mother liquor, in general, is detrimental to the growth of the crystal. The ion adsorption of the impurity salt on the crystal surface covers the active region of the crystalline surface and slows the crystal growth rate. Sometimes due to impurities in a certain crystal surface on the choice of adsorption, limiting the growth of crystals, affecting the crystal particles and color. This is also one of the reasons for the smaller size of ammonium sulfate particles. In order to ensure the purity of ammonium sulfate, Ammonium Sulfate when the use of sulfuric acid, I plant in the plant into the raw materials to choose the higher cost of the manufacturers and long-term cooperation of customers priority; into the factory sulfuric acid test is strictly prohibited unloading.
(4) every three months to carry out a large acid washing (the acidity control in 15%, and then washed to ensure adequate washing of the saturator), to ensure smooth equipment.
(3) to shorten the mother tank cleaning cycle, from 1 year to six times a year to reduce the bottom of the mother tank deposition crystal ratio.
Ammonium sulfate production in the color change is more common, in order to prevent the production of substandard color ammonium sulfate products, need to observe from time to time in production, from time to time to adjust for different problems to choose different measures to solve different color changes.