fractional column的用法和样例：
例句
- 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。
