Deodorization of used engine oil
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In the current market for deodorizing used engine oil, there are methods for refining fuel oil from used engine oil, hydraulic oil, heat transfer oil, and transformer oil. From an environmental perspective, it has both advantages and disadvantages. On the one hand, it solves the problem of handling these waste oils ； (Statistics show that China generates 8 million tons of such waste oil per year); on the other hand, it also helps to address some energy consumption issues. However, due to the imperfections in these processing techniques, environmental pollution is caused during the recycling and reuse in production processes. Most of the existing processes use ‘earth furnaces’ for processing, and a very pungent odor is generated during production. There are also certain security risks. Analyze whether this odor is similar to that of light oils in petroleum refining fractions – is it the smell of thiols? Are thiols also produced during the refining of these used oils?
Due to high-temperature thermal cracking and the presence of sulfides, it becomes dark and smelly; traditional acid-base washing methods are insufficient to achieve satisfactory results. Currently, there are specialized manufacturers in the market that produce agents for decolorization and deodorization, which can be added directly to carry out these processes, combining impurity removal, odor elimination, and decolorization in one step.
But most of the so-called deodorants on the market these days are just scent cover-ups; they address the symptoms rather than the root cause. The problem with this odor has not been resolved at its root. Firstly, the raw material is used engine oil, which contains many performance additives ； These additives also undergo fission during the distillation process; there are too many of them, and it’s not known exactly what substances they are. If it’s possible to find out what substance is emitting that smell, then there will still be a way to solve it.
Products manufactured using used engine oil as raw material are just that from the start. If its molecular structure can be reorganized, I think it’s still a viable approach.