US 12,172,144 B2
Use of supercritical CO2 as solvent for organic polymers in a method for coating urea-containing granules
Yevgeny Makhynya, Mülheim (DE); and Tarek El Hawary, Holzwickede (DE)
Assigned to thyssenkrupp Uhde GmbH, Dortmund (DE); and thyssenkrupp AG, Essen (DE)
Appl. No. 17/254,117
Filed by thyssenkrupp Industrial Solutions AG, Essen (DE); and thyssenkrupp AG, Essen (DE)
PCT Filed Jun. 14, 2019, PCT No. PCT/EP2019/065758
§ 371(c)(1), (2) Date Dec. 18, 2020,
PCT Pub. No. WO2019/243204, PCT Pub. Date Dec. 26, 2019.
Claims priority of application No. 10 2018 210 030.6 (DE), filed on Jun. 20, 2018.
Prior Publication US 2021/0268460 A1, Sep. 2, 2021
Int. Cl. B01J 2/00 (2006.01); B05D 1/02 (2006.01); C07C 273/10 (2006.01); F25J 1/00 (2006.01)
CPC B01J 2/006 (2013.01) [B05D 1/025 (2013.01); C07C 273/10 (2013.01); F25J 1/0027 (2013.01); F25J 2210/80 (2013.01); F25J 2220/80 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A process for coating urea-containing granules with organic polymers, the process comprising:
compressing and condensing gaseous carbon dioxide to obtain liquid carbon dioxide, wherein the compressing of the gaseous carbon dioxide occurs in a first step in a low-pressure compression step and in a second step in a high-pressure compression step, wherein the low-pressure includes from 5 bar to 10 bar and the high-pressure includes from 20 bar to 35 bar;
increasing at least one of pressure or temperature above a critical point of carbon dioxide to obtain supercritical carbon dioxide;
dissolving an organic polymer in the supercritical carbon dioxide to obtain a polymer-containing solution; and
mixing the polymer-containing solution by at least one of spraying the polymer-containing solution onto or bringing the polymer-containing solution into contact with urea-containing granules, in which
a simultaneous or subsequent lowering of temperature and/or pressure below the critical point of carbon dioxide occurs, and
coated urea-containing granules and gaseous carbon dioxide are obtained.