Anti-crystallization automotive urea solution and preparation method thereof

Abstract

The invention belongs to the technical field of vehicle tail gas treatment, and particularly relates to an anti-crystallization vehicle urea solution and a preparation method thereof. The anti-crystallization urea comprises the following components: high-purity urea, an anti-crystallization additive and deionized water. According to the invention, a total ammonium system formula and a lightweight process chain are used for synergistically inhibiting crystals: micro-dose ammonium salt is introduced at a formula end, crystal faces are selectively adsorbed, the growth rate is reduced, the induction period is prolonged, and adhesion is weakened; ammonium carbamate / ammonium bicarbonate is used for providing trace free ammonia and mild buffering, so that isocyanate is promoted to be preferentially hydrolyzed / ammonolyzed, and high-melting-point phases such as cyanuric acid and the like are reduced from the source; ammonia type strong acid cation resin terminal polishing is carried out, heterogeneous nucleation sites such as calcium, magnesium, iron and copper are removed, closed-loop cooperation of vacuum degassing, absolute value microfiltration and low-temperature short-time induced crystal refiltration is matched, the nucleation rate, crystal growth and secondary phase generation are reduced at the same time, nozzle / mixer evaporation-recrystallization and freeze-thaw insoluble substances are reduced, and the crystallization efficiency is improved. And stable atomization and ammonia-tail gas mixing are realized.

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