Production process of urea granules for vehicles

The production process comprises the following steps: sequentially pressurizing liquid carbon dioxide and liquid ammonia, introducing the pressurized liquid carbon dioxide and liquid ammonia from the bottom of a urea synthesis tower, and carrying out a reaction to obtain a synthesis liquid; the synthetic liquid is sequentially introduced into a stripping tower and a rectifying tower, unreacted gas and other redundant impurities in the synthetic liquid are removed, and a urea solution is obtained; introducing the urea solution into an evaporation heater, and heating, evaporating and concentrating the urea solution to obtain urea crystals; adding the urea crystals into a heating melting box of granulation equipment, and heating and melting the urea crystals; in response to completion of crystallization and melting of the urea, the liquid booster pump is controlled to pressurize the molten urea, so that the urea enters the solid-liquid rotary separator and flows back to the heating and melting box to be accelera