| 摘要 |
<p>A method for recovering methanol from sulfur-based wood pulping process vapors (22), which contain at least methanol and dimethyl disulfide. The method involves three steps. The first step consists of introducing the vapors into a first distillation tower (12) at a vapor introduction point (23). The second step consists of introducing water into the first tower at a point (25) above the vapor introduction point. The third step consists of heating liquid which is in the first tower below the vapor introduction point so that a liquid stream flows from the bottom (26) of the first tower and a gas stream flows from the top (27) of the first tower. The liquid stream contains most of the methanol originally in the vapors. The gas stream contains most of the dimethyl disulfide originally in the vapors. The liquid stream can then be distilled in a second distillation tower (13) by conventional distillation to produce dry methanol (32). The first and third steps can be combined by introducing sufficiently heated vapors. When the vapors contain more than sixty percent water, then there need be only two steps. The first step consists of introducing the vapors into a first distillation tower at a vapor introduction point. The second step consists of heating liquid which is in the first tower below the vapor introduction point so that a liquid stream flows from the bottom of the first tower and a gas stream flows from the top of the first tower. The liquid stream can then be distilled in a second distillation tower by conventional distillation to produce dry methanol.</p> |
