| 摘要 |
FIELD: process engineering.SUBSTANCE: invention relates to reduction in aerosol emissions at urea pelletiser. Urea pelletising plant comprises pelletiser producing urea from urea concentrated solution with emissions of dust, ammonium and ammonium isocyanate. Proposed method comprises the step of dust removal in scrubber wherein major dust particles are removed, the aerosol step with specially designed spraying and collection sites to release the first air and ammonium flow and second ammonium isocyanate and water flow. Note here that said second flow is directed to isomerisation step whereat ammonium isocyanate fraction is isomerised to urea. Note also that ammonium isomerisation to urea is performed at evaporator with low-pressure steam feed to column foot to convert urea formed therein into liquid phase. Remained ammonium and carbon dioxide is discharged from column header.EFFECT: reduced emissions, higher efficiency.13 cl, 1 dwg |
