Polymerizer We are manufacturing the polymerizer columns.The polymerizer column contains a series of trays with holes in them capped by inverted cups. The vaporized crude drifts up through the trays and around inverted cups, with the appropriate fraction liquefying at each tray. "Light ends" -- methane, ethane, propane, and butane -- are drawn off from the top. Below that is "straight-run gasoline", which used to be the only gasoline there was, but there's more in the mix now, as discussed below. Other fractions drawn off further down the column include naptha, heavy naptha, kerosene, "gas oil" -- and finally what is known as "residual oil" or "resid", which won't boil in the atmospheric column
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