Preparation method of low-temperature-resistant car urea solution

Abstract

The invention relates to a preparation method of low-temperature-resistant car urea solution, and belongs to the technical field of a chemical process. High-temperature and high-pressure steam is used; through diffusion effect, condensed water in fiber cells fast evaporates and expands; the lignin coating effect and a cellulose crystallization structure are broken; the material porosity is obviously increased; then, the covalent bond is used for crosslinking free amino acid or amino groups of the soybean protein molecules with ammonium alginate to form a reticular space structure; under the basic condition, the soybean protein molecules swell so that the molecule structures loosen; peptide chains extend; hydrophobic groups are sufficiently exposed; through heating denaturation treatment, the materials are decomposed into pores of the materials; a viscous porous structure formed by multilayer micro fiber can be formed; the larger specific surface area and a great number of active sitescapable of being combined with metal ions are realized; the urea solution is purified; the prepared pure urea solution is mixed with ammonium acetate and ammonium chloride capable of lowering the water solution freezing point; the low-temperature-resistant performance of the urea solution is improved.

Description

technical field [0001] The invention relates to a preparation method of a low-temperature resistant vehicle urea solution, which belongs to the technical field of chemical technology. Background technique [0002] The current global energy shortage, climate warming, and environmental protection are becoming increasingly severe. In this context, the hazards of nitrogen oxides and particulate matter emitted by diesel vehicles to human health and the atmospheric environment have attracted great attention. According to reports, countries all over the world are committed to reducing these two emissions research, including improving fuel quality, implementing in-machine purification technology and out-of-machine purification technology for after-treatment of exhaust gas. As far as our country is concerned, the implementation of the national "IV" emission standard means that the emission of vehicle exhaust must adopt more advanced technology. A large number of experimental studie...

AI Technical Summary

Problems solved by technology

The urea solution with this concentration has the lowest crystallization point, and it will crystallize when it is lower than -11°C. In actual use, it will be completely frozen at -20°C, which restricts its use in cold winter weather in the north, especially in the northeast.

Adding a modifier to reduce the freezing point of the urea solution for vehicles is the most convenient and low-cost method, but due to the high requirements of the SCR catalyst on the purity and cleanliness of the urea solution for vehicles, metal salts that can significantly reduce the freezing point of the aqueous solution cannot be used, making the modification The selection range of the neutralizer is very limited, the inorganic salt can only choose ammonium substances, and most of the organic modifiers choose amines or amides

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