| 摘要 |
<p>A multi-step process for extracting palm oil (528) from a feed liquor (500) consisting of a mixture of oil, free water, bound water, suspended solids (includes fine and coarse fibrous solids and sand), dissolved solids and gums from prior processing steps in the palm oil extraction process, while achieving environmental compliance and reducing the carbon and water footprints. There is no highly polluting liquid effluent produced as a by-product that must be treated prior to discharge. In the new process, most (but not all) of the free water in the feed liquor is removed by evaporation (519), using oil in the feed to the evaporator as a fluidizing medium, to convert the effluent discharged from the clarification process from a liquid form to more easily disposable solid form (514). Removing most of the free water breaks oil/ water emulsions and leads to the gums becoming insoluble and forming a gel-like substance that readily precipitates from the oil. Removal of the gums from the evaporated liquor is achieved by a decanting centrifuge (513), using suspended solids in the feed to the decanter as a carrier for conveying the gums out of the decanting centrifuge. Various clarification plant configurations incorporating the abovementioned steps are possible using either two-phase or three- phase decanting centrifuges. In the simplest clarification plant configuration, the evaporation step precedes the decanting step and the suspended solids required for the removal of precipitated gums by the decanting centrifuge are present in the feed to the evaporator. To minimize the likelihood of evaporator fouling, it is advantageous if the decanting step (513) precedes the evaporation step (519), and the evaporated liquor (521) is either recycled completely, or recycled after separating most of the oil by using a settling tank (526), and mixed with the feed liquor (500) to facilitate removal of gums by the decanting centrifuge (513).</p> |
