Patent ID: 8440159

Claim:
A method for extracting a purified ammonium salt and purified methanol from a secondary condensate comprising: subjecting a contaminated primary condensate to stripping in a stripper, expelling stripper gases from the stripper, the stripper gases containing methanol, water, volatile sulphur-containing substances and ammonia, condensing the stripper gases and forming a secondary condensate, conveying the secondary condensate to a storage volume, adding an acid to the secondary condensate in the storage volume, acidifying the secondary condensate with the acid, the acid forming an ammonium salt with the ammonium contained in the secondary condensate, a net inflow of water via the secondary condensate and the addition of acid maintaining a concentration of ammonium salt in the storage volume at 1-20% below a level at which the ammonium salt is precipitated, withdrawing an ammonium-salt containing mixture from the storage volume, withdrawing 5-50% of the ammonium-salt containing mixture withdrawn from the storage volume into a collection-vessel tube and conveying to a collection-vessel to form a collection vessel mixture, stirring and/or circulating the collection-vessel mixture in the collection-vessel with a high-water content and expelling methanol and volatile sulphur-containing substances in gas form from the storage volume, transferring the expelled methanol and volatile sulphur-containing substances to a condenser, condensing the expelled methanol in the condenser while the volatile sulphur-containing substances remain in gas form, conveying the condensed methanol to a reactor, removing the volatile sulphur-containing substances in gas form from the condenser, adding an oxidizing agent to the condensed methanol in the reactor, converting remaining liquid soluble malodorous sulphur-containing substances in the condensed methanol to mainly odorless substances, and circulating a mixture of methanol and oxidizing agent in the reactor while cooling the mixture of methanol and oxidizing agent in an indirect heat exchanger.