May 14, 2021
As a kind of hazardous waste (HW08), waste mineral oil is toxic and flammable. At the same time, it also has great recycling value and can be regenerated into fuel oil, base oil, etc. It is precisely because of this dual attribute of waste mineral oil that at present, most of the waste mineral oil in China is recycled through small vendors who do not have the corresponding business qualifications, and further enters the non-standard recycling link, which can benefit the ecological environment and the environment while making profits. Human health causes huge potential harm.
It is of great significance to study the production characteristics, pollution characteristics and environmental risks of waste mineral oil. The type, production process, production link and production waste coefficient of waste mineral oil are analyzed. The source and type of the main pollutants in waste mineral oil are analyzed. The content and composition of the main pollutants in waste mineral oil are analyzed through experiments. The law of migration and transformation of various pollutants in the process of waste mineral oil treatment and disposal, combined with the law of migration and transformation, constructs exposure scenarios, selects simplified models, and studies the environmental risks in the process of waste mineral oil treatment and disposal. The conclusions obtained are as follows:
(1) Due to different production processes and working environments of different waste mineral oils, there are obvious differences in the degree of oil loss and production waste. Among them, the production and waste coefficients of waste anti-rust oil, waste lubricating oil and waste foundry oil are relatively high. The lowest is 0.1~0.3; the second is waste vehicle lubricating oil, waste quenching oil, waste refrigerating machine oil and waste hydraulic oil, which are 0.6~0.9; and waste white oil has the largest waste production coefficient, about 1.0.
(2) The heavy metals in waste mineral oil mainly come from additives (Zn, Mo, and Ba) and in the process of use (Cr, Ni, Pb and Cu), of which heavy metals from additives account for the main part. The main sources of benzene series and polycyclic aromatic hydrocarbons are base oil, deterioration during use, and fuel oil mixing. The mixing of fuel oil has a greater impact on the content of benzene series in waste mineral oil.
(3) During the regeneration process of waste mineral oil, all the heavy metals in it enter the waste of the regeneration process, most of which enter the cracking residue, and the product oil does not contain heavy metals. Because in the cracking process, new benzene series and polycyclic aromatic hydrocarbons will be generated due to high temperature, and some of them will be adsorbed and removed during the adsorption refining process, making the content of benzene series and polycyclic aromatic hydrocarbons present semi-finished oil products. Oil feedstock oil.
(4) During the incineration of waste mineral oil, the content of heavy metals in the flue gas will increase with the increase of temperature; the content of benzene series (except benzene) in the flue gas will appear with the increase of temperature The obvious downward trend is mainly due to the higher the temperature, the more complete the combustion of these benzene series; the content of benzene and polycyclic aromatic hydrocarbons in the flue gas shows a trend of first rising and then falling as the temperature rises. The reason is that benzene and polycyclic aromatic hydrocarbons will not only decompose due to oxidation during incineration, but also be synthesized due to high temperature. The decomposition and synthesis rates are different at different temperature sections, making their content rise first and then decrease as the temperature rises.
(5) When waste mineral oil is used as fuel in boiler blending or paint room, the cumulative non-carcinogenic risk under three different working conditions is 0.023, 0.078 and 0.050, respectively, and there is no obvious non-carcinogenic risk, and the cumulative carcinogenic risk is 6.50×10-6, 2.55×10-5 and 2.26×10-5, so waste mineral oil is used as a boiler blended combustion or paint room fuel, there is a human health risk. The cumulative carcinogenic risk and non-carcinogenic risk of the pyrolysis residue in the open-air storage scenario are 4.91×10-6 and 0.014, respectively, and the cumulative carcinogenic risk and non-carcinogenic risk in the landfill scenario are 1.32×10-5 and 0.037, respectively. Therefore, the open storage of pyrolysis residues and the landfill of domestic garbage have human health risks. The cumulative carcinogenic risk and non-carcinogenic risk of waste filter sand in the open-air storage scenario are 9.44×10-7 and 0.0044, respectively, and the cumulative carcinogenic risk and non-carcinogenic risk in the landfill scenario are 1.75×10-6 and 0.0034, respectively. Therefore, there is no human health risk in the open-air storage of waste filter sand, but there is a human health risk in the domestic waste landfill.