Process for preparing urea solution for vehicles

Abstract

The invention provides a process for preparing urea solution for vehicles. The process includes steps of (1), weighing a raw material; (2), freezing tap water to obtain blocks, and then tossing out moisture by the aid of a centrifugal machine to obtain tossed moisture which is high-purity water; (3), adding the high-purity water obtained at the step (2) into urea which is the raw material, stirring the high-purity water and the urea, heating the high-purity water and the urea until the temperatures of the high-purity water and the urea reach 50-70 DEG C so as to obtain urea solution, adding activated carbon into the urea solution, carrying out adsorption and then filtering the urea solution to obtain relatively pure urea solution; (4), carrying out ion exchange on the relatively pure urea solution obtained at the step (3) to obtain pure urea solution; (5), uniformly mixing the pure urea solution, dimethyl silicone oil and glycerol with one another to obtain the urea solution for the vehicles. The process has the advantages that biuret, metal ions, insoluble substances and the like in the urea solution for the vehicles can be effectively adsorbed by the modified coal-based activated carbon, the modified coal-based activated carbon is high in adsorption efficiency, and accordingly the quality of the urea solution for the vehicles can be improved.

Description

technical field [0001] The invention relates to the field of vehicle tail gas treatment additives, in particular to a preparation process of urea solution for vehicles. Background technique [0002] In recent years, air quality has continued to decline, and smog has become increasingly serious. Motor vehicle exhaust emissions account for about 20% to 25% of the causes of smog on average. Exhaust emissions from automobiles (especially diesel vehicles) have become one of the main sources of air pollution, and nitrogen oxides (NOx) are the main components of automobile exhaust. NOx needs to be controlled by exhaust gas treatment devices, such as: lean nitrogen oxide adsorption technology (LNT), selective catalytic reduction technology (SCR), oxidation catalytic converter technology (DOC), exhaust gas recirculation + particulate filter technology (EGR+ DPF), etc., the SCR system is widely used in the exhaust gas treatment of heavy-duty diesel locomotives. [0003] SCR technolo...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent application 201410488044.3 discloses a method for preparing urea for vehicles, which comprises crystalline urea and high-purity water, but the preparation of urea for vehicles increases the production cost of urea solution for vehicles and reduces the profits of urea manufacturers for vehicles

In addition, the use of reverse osmosis equipment to produce high-purity water from industrial brine is inefficient and of poor quality, and the production takes a long time and costs high

[0005] Moreover, the existing urea for vehicles is all catalyzed to make the exhaust gas meet the National IV standard, and few of them meet the National V diesel vehicle exhaust emission standard.