The liquid drawn off from the bottom of the first fractionating column, the primary fractionating column, is fractionated again in another column under low pressure. 从第一个分馏塔即初分塔底部下来的液体，再在低压下进入其余的分馏塔分馏。
Water wash injections, typically continuous and low volume, are used to avoid salt build-up or reduce corrosiveness in the distillation column overheads. 水洗水注入设施，典型的是连续小量，避免结盐或减缓分馏塔顶的腐蚀。
