Device for continuously producing low-biuret vehicle urea solution and production process thereof

Abstract

The invention belongs to a device for continuously producing a low-biuret vehicle urea solution and a production process thereof. The device comprises a urea synthesis high-pressure ring unit, whereina liquid phase outlet at the bottom of a stripping tower in the urea synthesis high-pressure ring unit is connected with a liquid phase inlet of a medium pressure flash tank in a urea synthesis medium-low-pressure unit; a liquid outlet of a pre-evaporator in the urea synthesis medium-low-pressure unit is connected with a first liquid inlet of a liquid distribution groove; a second liquid inlet onthe top of the liquid distribution groove is connected with a desalted water pipeline; a liquid outlet on the bottom of the liquid distribution groove is connected with a product storage tank througha product conveying pump, a tee joint and a third regulating valve. The device and the process have the advantages that the biuret content can be controlled to be 0.16 percent or below, so that the quality of the vehicle urea solution is obviously improved, confirming to the national relevant energy-saving and emission reduction policy; the device is applicable to continuous large-scale production.

Description

technical field [0001] The invention belongs to the technical field of urea for vehicles, and in particular relates to a device and a production process for continuously producing low-biuret vehicle urea solution. Background technique [0002] In order to meet the National IV emission standards, diesel vehicles need to use selective catalytic reduction (SCR) technology to treat diesel vehicle exhaust. Diesel vehicle exhaust treatment fluid can convert nitrogen oxides in diesel engine exhaust into nitrogen and reduce air pollution. Diesel vehicle exhaust treatment fluid is composed of 32.5% vehicle urea and 67.5% high-purity water. The national standard GB29518-2013 "Diesel Engine Nitrogen Oxide Reducing Agent Urea Aqueous Solution (AUS32)" requires sodium, magnesium, aluminum, potassium, Calcium, iron content ≤ 0.5ppm, nickel, copper, chromium, zinc ≤ 0.2ppm, and biuret content ≤ 0.3wt% is also required; biuret is a by-product in the process of urea synthesis, and the biuret...

AI Technical Summary

Problems solved by technology

And according to research, it is found that the level of biuret content is related to the blockage of the nozzle of the SCR system of diesel vehicles; in addition, as mentioned above, the method of dissolving urea particles for vehicles with water is too slow, and it takes 6 hours without heating. -8 hours, if the method of heating is used, it will take at least 1 hour, the dissolution efficiency is low and large-scale continuous production cannot be realized, and it is impossible to ensure that the urea solution for vehicles meets the relevant national standards

Images