Shisheng process for production of NPK compound fertilizer granulation
Nitrogen phosphorus potassium compound fertilizer is called for short NPK, nitrogen (N), phosphorus (P), potassium (K) containing in compound fertilizer is made from chemical method, is also called ternary compound fertilizer. The main types are monoammonium phosphate, diammonium phosphate, potassium dihydrogen phosphate.
Nitrogen and phosphorus or nitrogen phosphorus potassium compound fertilizer and the preparation method, the steps are as follows:
(1) the first dilute sulfuric acid, phosphoric acid, washing liquid ammonia and in part from the gas-liquid separator for neutralization reaction in reactor adding tube, high temperature reaction after the formation of the slurry is sprayed into the granulator, while adding the solid raw material together with the material returning to form a solid material bed granulator rolling in, and in the solid in the material bed by spraying ammonia axis is sprayed into the ammonia by the granulation, the formation of solid material and wet granulation tail gas;
(2) the tail gas from gas-liquid separator enters the gas-liquid separator and circulating pump of the washing liquid in the injector fully atomized mixture formation, gas-liquid mixture enters the gas-liquid separator for separation, a part of the proceeds to the washing liquid through a circulating pump into the Venturi ejector and tail gas mixture, another part of the conveying pump to tubular reactor, gas obtained by fan pressurization into the cyclone further washing washing tower;
(3) the solid granulation machine wet materials into a dryer and dry hot air flow drying and after drying, material into the sieve of material grading machine, dry tail gas into the cyclone recovery most dust, recycling dust as material return return granulator, separated gas drying exhaust fan pressure to enter into the cyclone further cleaning dust scrubber;
(4) gas drying tail gas and gas-liquid separator from the dryer exhaust fan to enter the cyclone scrubber, at the same time will dilute phosphoric acid, sulfuric acid and water into the swirl scrubber, forming a washing liquid, a part of the washing liquid by the circulation pump for dry tail gas into the tower, spray and wash, the rest of the washing liquid overflow to the gas-liquid separator, gas emptying after washing;
(5) screen large particle extension of screening by crusher with fine powder screening down as material return return granulator; screening qualified particle except some return granulator maintain returned material stability, the rest of qualified particle cooling products.