Oil Recovery From Spent Bleaching Clay And Its Comprehensive Utilization

A bleaching technology is necessary when refining oil, the methods of bleaching are difference, but the most general one is absorption methods for bleaching. Absorbents such as natural bentonite, activated bentonite and activated carbon are usually used. Considering activated bentonite is better than the other two absorbents in bleaching and economic efficiency, Oil factory take the use of activated bentonite for bleaching. In the process of refining, activated bentonite which equal 2%~5% of oil in weight is used as absorbent. After bleaching, it will lose its activity and become spent bleaching clay which absorbs much oil in the process of bleaching. If spent bleaching clay can't be utilized rationally, it will not only waste resource but also pollute environment. So comprehensive utilization of spent bleaching clay is of great significance.The main contents and results are summarized as follows:1. Through experiment on spent beaching earth with plunger-styled pressing apparatus, approaching oil-point pressure and strain, the relationship between oil-extracting rate of spent beaching earth and press,the relationship between stress and strain in the cold-pressing processing of spent beaching earth and then revealing the pressing of spent bleaching earth for getting oil is more difficult and less effective than common oil.2. With spent bleaching clay of oil refining as the raw material, oil was recovered by N-hexane. The impact of the water content in the spent bleaching clay on the effect of extraction and the impact of temperature, material:N-hexane, solvent extraction times on the residual oil content in the spent bleaching clay were discussed. When the water content in the spent bleaching earth is 2.5%, the effect of extraction is better. The optimum condition of extraction are temperature 55℃,material:N-hexane=1:1.5(W/V).When the solvent extraction times is 5, the residual oil content in the spent bleaching clay is less than 2%.3. The quality of the oil recovered from spent bleaching clay go bad greatly. It is very difficult for edible oil. Analysis the reason through observing the micro-structure of activated bentonite and spent bleaching clay by use of SEM.4. With oil recovered from spent bleaching clay as the raw material, biodiesel were obtained by two-step way. Through single factor tests and orthogonal test, the optimum conditions of easterification were investigated: the molar ration of methanol to acid 8:1, catalyst dosage 2.5%, reaction time 3h, reaction temperature 60℃; the optimum conditions of easterification transeasterification were investigated: the ration of methanol to oil 35%, catalyst dosage 1%, reaction time 1.5h, reaction temperature 60℃;The conversing of transeasterification can reach 98%. The quality trait of bioliesel accords with the standard of ASTM.5. The kind and the amount of raw materials, the parameter of molding along with the impact on stress-resisted intensity of the bricks of the oil content in the spent bleaching clay are studied in view of capability of the bricks.The stress-resisted intensity of the no-fired bricks reach standard of MU 15 of GB11945-1999 and the folding-resisted intensity of the no-fired bricks reach standard of MU 10 of GB11945-1999.