| 摘要 |
A polyisocyanate production method that can allow effective use of hydrogen chloride produced secondarily in a polyisocyanate production process, while allowing reduction of environmental burdens, and a polyisocyanate production system for performing the polyisocyanate production method. After chlorine is allowed to react with carbon monoxide to produce carbonyl chloride in a carbonyl chloride producing reactor 2, the carbonyl chloride produced in the carbonyl chloride producing reactor 2 is allowed to react with polyamine in an isocyanate producing reactor 3 to produce polyisocyanate. Then, after hydrochloric gas produced secondarily in the isocyanate producing reactor 3 is purified in a hydrogen chloride purifying column 4, the purified hydrochloric gas is oxidized in a hydrogen chloride oxidizing reactor 6 to produce chlorine. Thereafter, the chlorine thus produced is supplied to the carbonyl chloride producing reactor 2 from a chlorine resupply line 8, so that it is allowed to react with carbon monoxide to produce carbonyl chloride. |
