| 摘要 |
<p>Treatment of oily sludge (e.g. from settlers, sand filters or flotation units used to remove oil from refinery effluents etc.) comprises (a) filtering the sludge on a precoated surface filter, and (b) extracting the filter cake with a hydrocarbon solvent and/or stripping it with steam. The precoat material is pref. diatomaceous earth. The surface filter can be a plate-, tube- or candle-type filter. The sludge can be diluted with water and/or mixed with a filter aid (esp. diatomaceous earth) before filtration. Filtration is pref. effected under pressure at a rate of 0.05-10 (esp. 0.5-2.5) m3/m2/hr.</p> |
