Method and apparatus for treating urea aqueous solution
US10280094B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2017 |
| Grant date | May 7, 2019 |
| Priority date | — |
| Expiry date | May 16, 2037 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2301/08
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method for treating a urea aqueous solution includes a first stripping step of steam stripping an aqueous solution containing urea, ammonia and carbon dioxide at 0.2 to 0.6 MPaA in a first stripper to separate ammonia and carbon dioxide from this aqueous solution into a gas phase; a hydrolysis step of hydrolyzing urea in the solution obtained from the first stripping step at an LHSV of 10 to 20 h−1, at 1.1 to 3.1 MPaA and 180 to 230° C. in a catalytic hydrolyzer; and a second stripping step of steam stripping a liquid obtained in the hydrolysis step in a second stripper to separate ammonia and carbon dioxide from this liquid into a gas phase. The residual urea concentration can be reduced to 1 ppm or lower; the residual ammonia concentration can be decreased; LHSV can be increased; and an increase in apparatus size is minimized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.