Method and device for preparing thermal-process phosphoric acid and recovering thermal energy

Abstract

The invention discloses a method and device for preparing thermal-process phosphoric acid and recovering thermal energy. The method is characterized in that a micro absorber absorbs reaction heat of hydration reaction; after passing through the micro absorber, the reaction heat is brought into a separation tank by a gas-liquid mixture; firstly, heat of a gas phase and heat of a liquid phase are respectively absorbed by tail gas heat recovering equipment and a strong phosphoric acid cooler; then, the heat of the gas phase and the heat of the liquid change is neutralized; finally, the heat is conveyed to an evaporation device of a yellow phosphorus boiler in a saturated soft water form to be steamed; the preparation of the phosphoric acid is realized; meanwhile, the heat can be recovered; the mass of oxygen gas in an oxidizing agent is 1.2 to 2.6 times of the mass of yellow phosphorus; a hydrated agent is water or solutions with different P2O5 mass percents; the mass of water in the hydrated agent is 0.29 to 6 times of the mass of yellow phosphorus; the mass of water of the prepared saturated soft water is 1 to 20 times of the mass of the yellow phosphorus. The method and the device have the advantages that the recovery rate of the combustion heat of the yellow phosphorus and the reaction head of phosphorus pentoxide can be improved; the energy sources are favorably saved; the production cost is effectively reduced.

Description

technical field [0001] The invention relates to a method for preparing thermal phosphoric acid and recovering heat energy and a device thereof, belonging to the technical field of phosphoric acid preparation and recovery and utilization of low-level heat energy. Background technique [0002] Phosphoric acid is an important chemical intermediate product and a common raw material for the synthesis of most phosphates and some phosphoric esters and other phosphorus-containing compounds. It is widely used in food, medicine, electronics, petroleum, metallurgy, chemical industry and other industries. According to the production process, the sources of phosphoric acid include wet process phosphoric acid and thermal process phosphoric acid. Wet-process phosphoric acid uses strong acid—usually sulfuric acid, but also nitric acid, hydrochloric acid, fluosilicic acid and phosphate rock to undergo metathesis reaction to obtain crude phosphoric acid with more impurities, which is generall...

AI Technical Summary

Problems solved by technology

[0004] Invention patent CN201531862U yellow phosphorus combustion heat energy recovery device proposes a more secure yellow phosphorus combustion heat energy recovery device, which uses a certain gas as an intermediate heat exchange medium, which can effectively avoid phosphorus pentoxide caused by the rupture of boiler heat exchange exhaust pipes It reacts with soft water to generate phosphoric acid and corrodes equipment. The patent does not mention the recovery of heat of hydration and heat integration

[0006] Invention patent CN102910602A double-zone high-efficiency recovery of yellow phosphorus combustion heat energy device proposes a heat energy recovery device similar to a phosphorus-burning boiler, without considering the recovery of high-temperature tail gas heat energy and hydration reaction heat

[0007] Invention patent CN102556990A The device for absorbing the heat energy of yellow phosphorus combustion by heat-conducting oil proposes a device that uses heat-conducting oil for heat exchange and then releases heat. This invention needs to use heat-conducting oil as an intermediate heat-exchange medium, and does not mention the high-temperature tail gas heat energy of the device and recovery of heat of hydration reaction

The reaction is reflected in the reaction between phosphorus pentoxide and water, and the absorption of phosphorus pentoxide in the gas phase is released. The inlet of the gas phase material is a mixed gas of nitrogen, oxygen and gaseous phosphorus pentoxide, and the outlet is mainly nitrogen and oxygen. , the absorbent is mainly an aqueous solution containing phosphoric acid or polyphosphoric acid, and its outlet concentration is higher than that of the imported one. At present, there is no microreactor for this system. For this reason, the present invention introduces a microreactor into the process and proposes a suitable microreactor. Reactor characteristic size

Images