Mineral oil refers to the mixture of refined liquid hydrocarbons obtained from petroleum, which is obtained from crude oil by regular pressure and vacuum fractionation, solvent extraction and dewaxing, and hydrofining[1]。
Mineral oil includes light and heavy fuel oil, lubricating oil, cooling oil and other mineral hydrocarbons.Mineral oil can float on the surface of water, affecting the exchange of oxygen between air and water;It can also be dispersed in water, adsorbed on suspended particles or emulsified oil in water, which is oxidized and decomposed by microorganisms in water, consumes dissolved oxygen in water and worsens water quality.[2]
On October 27, 2017, the International Agency for Research on Cancer of the World Health Organization published the list of carcinogens. Untreated or lightly treated mineral oil is included in the list of Class I carcinogens.[6]
Chinese name
mineral oil
Foreign name
mineral oil
Hazards
Mineral oil is not absorbed or digested in human intestinal tract
Purpose
Lubricants, pesticides, etc
Character
Colorless translucent oily liquid
Composition
Including cycloalkanes (MOSH) and alkyl substituted aromatic hydrocarbons (MOAH)
Mineral oil is colorless and translucent oily liquid with no or almost no fluorescence. It is odorless and tasteless when cold. It has a slight oil smell when heated. It is insoluble in water and ethanol, soluble in volatile oil, and miscible in most non-volatile oils. It is stable to light, heat, acid, etc., but will slowly oxidize when exposed to light and heat for a long time[1]。
Main purpose
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For manufacturingWashing powder、Synthetic detergentSynthetic petroleum protein, pesticide emulsifier, etc.It can be used as coating agent in the food industry. According to the Hygienic Standard for the Use of Food Additives (GB2760-2014), it can be used for other candies and fresh eggs except gum based candies, and the maximum use amount is 5.0g/kg;Other use references: As a bread mold release agent, it is less corrosive to the baking tray and does not produce unpleasant odor;As a food machinery lubricant, it does not corrode machinery;In addition, it can also be used to extend the storage period of fruits, vegetables and cans[1]。
Security
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Allowable daily intake (ADI): high viscosity mineral oil 0~20mg/kg (FAO/WHO, 1995);Medium or low viscosity mineral oil Class I 0~1mg/kg (tentative), Class II and Class III 0~0.01mg/kg (tentative)[1]。
Composition of mineral oil
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As a complex hydrocarbon, mineral oil mainly includes straight chain alkanes, branched chain alkanes, alkyl substituted cycloalkanes (MOSH) and alkyl substituted aromatic hydrocarbons (MOAH). In addition, it also contains a small amount of alkyl free polycyclic aromatic hydrocarbons and sulfur and nitrogen containing compounds.The cumulative amount of MOSH in human body that is ingested through diet is the largest, and the parts with the highest MOSH content are lymph nodes and spleen.MOSH has low to medium toxicity. If the food contaminated by MOSH is consumed for a long time, it will cause great damage to human health.Generally, food grade white oil (liquid paraffin) is basically MOSH, while industrial grade mineral oil contains very high content of MOSH and 15%~35% of MOAH.[3]
Source of mineral oil in food
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In the process of planting, harvesting, drying and final processing, food raw materials will come into contact with mineral oil on the soil or ground, diesel oil, engine lubricating oil, incompletely burned gasoline and polluted air, which will pollute food with mineral oil.The specific pollution sources mainly include the following six aspects:[3]
Soil or ground pollution
The soil pollution in some areas of China is relatively serious. If the soil is polluted by mineral oil and exceeds a certain limit, it will be absorbed by some ingredients in food raw materials, and then enriched in plants.In addition, the harvested plants may also be polluted by mineral oil substances such as asphalt on the ground and lubricating oil dripping on the ground in the process of drying.The biggest problem with the contaminated raw materials is that mineral oil is difficult to be removed from the raw materials, resulting in the gradual enrichment of mineral oil in food raw materials. Through various food processing procedures, the finished products contain a large amount of mineral oil.[3]
Pesticide or insecticide and other substances
During the growth of crops, mineral oil contained in pesticides or insecticides will be absorbed by plants and enriched in plants, thus causing pollution to crops. Mineral oil pollution in crops will always exist in subsequent processing, ultimately affecting human health.[3]
Processing and production process
When food raw materials are processed and produced, if the solvent used in the extraction process is polluted by mineral oil, after a series of production processes, the solvent will migrate to the food, which will cause pollution of the finished food.[3]
Food packaging materials
In the process of food packaging, when recycled paper and recycled paper are used for packaging, the residual printing ink will be transferred to the foodpolystyreneAnd polyolefinPlastic packagingLubricants and adhesives contained in paper will also migrate mineral oil, which will eventually pollute mineral oil in food.[3]
Storage and transportation process
During the storage and transportation of food, due to the poor storage and transportation conditions, the mineral oil in the environment will be transferred to the food through the gap of the device, causing the food to be contaminated by mineral oil.[3]
Artificial participation
Although it is stipulated in the National Food Safety Standard for the Use of Food Additives (GB 2760-2014) that mineral oil can be used as defoamer, release agent, anti sticking agent and lubricant in fermentation process, candy, potato chips and bean products processing process, some illegal traders, for their own interests, use international methods to detect the omission that the detection limit of mineral oil is too high,It is often adulterated in oil, and artificially adding mineral oil will harm the interests of consumers.[3]
Hazards of mineral oil
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Mineral oil contains many substances harmful to human body, such as heavy metals, aromatic hydrocarbons and long-chain alkanes, which will cause harm to organisms.It is difficult for each organism to decompose mineral oil, resulting in the accumulation of toxic mineral oil in the organism, and finally reaching the human body through the food chain. It is difficult for the human stomach to absorb mineral oil. Once the mineral oil content exceeds the standard or the food containing mineral oil is ingested for a long time, it will cause great obstacles to the human digestive system,For example, long-term consumption of a large number of mineral oil contaminated food will cause vomiting, diarrhea, coma and other symptoms.What is more serious is that the human body will suffer from acute and chronic poisoning after ingesting industrial mineral oil by mistake, which will destroy various cells in the human body, thus causing damage to the nervous system.In addition, it can also damage the human respiratory system, reduce the number of red blood cells in the bloodRespiratory failureEtc.Therefore, people must pay attention to safe diet in daily food to ensure that there is no or little mineral oil intake.[3]
test method
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The detection methods of mineral oil in China are mainly divided into qualitative detection methods and quantitative detection methods.Among them, the qualitative detection method can only detect whether there is mineral oil in the sample. The detection steps are relatively simple, the price is relatively low, and the requirements for test instruments and conditions are relatively low.The quantitative detection method can not only detect whether there is mineral oil in food, but also detect the content of mineral oil. However, the detection steps are more complicated, and the price is relatively expensive, and the requirements for test instruments and conditions are high.[3]
Physical methods
(1) Sensory analysis
Food grade white oil can play the role of defoaming, polishing and sealing in food processing. Sensory analysis can be used to identify whether some foods contain mineral oil.The mineral oil in the oil can be observed by visual inspection. The edible oil mixed with mineral oil is darker than the pure oil;When mineral oil is mixed into grain, it has good gloss and cracks;Rub it with your hand, it will feel very smooth;Smell with your nose, there will be a smell of gasoline or vaseline;In addition, grain can also be placed in warm water, and oil will float on the surface of water.You can also judge whether there is mineral oil according to the taste of the edible oil you taste. When mineral oil exists, it will have a bitter taste. Because mineral oil is toxic and the accuracy and safety of this method are not high enough, it is not suitable for widespread use, nor can it be used for quantitative analysis and research.[3]
(2) Fluorescence method
Fluorescence method is based on the characteristics of fluorescence reaction of mineral oil to determine whether there is mineral oil.When the filter paper containing mineral oil is irradiated under the fluorescent lamp, it will show azure fluorescence, while the filter paper without mineral oil will not show color under the fluorescent lamp. This detection method is simple and fast, and is one of the more sensitive detection methods to identify whether there is mineral oil in food, but it is only applicable to pure oil.In case of deviation in the test results, the soap method can be used for further detection and determination.When mineral oil in grease is qualitatively detected by fluorescence method, the sample will not directly contact with optical elements, and there is no problem of instrument pollution.Due to its high low detection limit, its specific detection limit cannot be determined.In addition, liquid paraffin has no fluorescence characteristics, so fluorescence method is only used as an auxiliary detection method.[3]
Chemical method and instrumental analysis
(1) Saponification
Vegetable oil contains glycerides. Glycerides will undergo hydrolysis reaction under alkaline conditions to generate higher fatty acid sodium and glycerol. These reaction products are soluble in water, so the solution after reaction is transparent.But mineral oil cannot occurSaponification reactionIt is also insoluble in water, so the solution of vegetable oil containing mineral oil is still turbid after saponification reaction, and oil droplets are separated out.It is low cost, simple instrument and suitable for laboratory operation to judge whether vegetable oil contains mineral oil according to whether the solution after saponification reaction is turbid.However, the operation is complicated, the minimum detection limit of oil is 0.5%, the sensitivity is low, and the measurement error is easy to occur, especially when 1%~3% of the components in oil cannot be saponified, the error will be more serious.If ether is used as the extractant in the determination of saponification method, it can effectively reduce the error, prevent the negative sample from producing turbidity when judging the saponification result, and the detection limit will also be increased.[3]
(2) Secondary saponification
Because the test result of saponification method has large error and is easy to produce false positive, misleading the test result, the secondary saponification method is used to solve these problems.The secondary saponification method is carried out on the basis of the saponification method. The suspicious substances in the saponification method are repeatedly concentrated and extracted with petroleum ether to further increase the content of mineral oil. Afterwards, the operation is carried out according to the saponification method, and the presence of mineral oil is judged according to whether the solution is turbid after the saponification reaction.Compared with saponification method, the accuracy and precision of this method will be further improved, and the false positive will be avoided.[3]
(3) Infrared spectrometry
Infrared spectroscopy is based on the fact that the electrons in the molecule will absorb photons with the same energy as the electron transition energy when they transition, so that part of the infrared spectrum will be lost, that is, infrared absorption.Mineral oil is a complex mixture, so it is difficult to extract each kind of mineral oil separately for quantitative analysis, but only for the overall qualitative and quantitative analysis of mineral oil mixture.Compared with vegetable oil, mineral oil is generallySaturated aliphatic hydrocarbonIn the infrared spectrum, there is a stronger C-H absorption peak than vegetable oil, and we can judge whether there is mineral oil in vegetable oil according to the intensity of the C-H absorption peak.Since mineral oil is a C-H compound, there will be a strong C-H absorption peak in the infrared spectrum. The larger the absorption peak, the higher the content.This method is applicable to the content detection of C-H compounds for substances that do not contain C-H compounds, and this method is simple in operation, low in cost, does not damage samples, and is safe, environmentally friendly and fast in detection. However, this method has low sensitivity and is not suitable for the detection of mineral oils in foods containing vegetable oils, because vegetable oils also contain C-H bonds,There will also be C-H absorption peak under infrared light, which is easy to cause misjudgment.[3]
(4) Chromatography
1) Thin layer chromatography
The mineral oil extracted by cyclohexane is separated on the GF254 thin-layer plate. After the separation, the fluorescent spots produced by the mineral oil are observed under an appropriate ultraviolet lamp. Qualitative analysis is carried out according to the spot Rf value, and quantitative analysis is carried out according to the spot size and color depth.This mineral oil detection method is simple and fast, which is suitable for grassroots detection and major events of drinking water and food pollution. The detection limit is very low, reaching 1 μ g, and the recovery rate is very high, reaching 95%.This method is based on the principle that mineral oil will emit fluorescence under the fluorescent lamp. If the corresponding mineral oil spectral band can be observed, it means that there is mineral oil. If the corresponding mineral oil spectral band cannot be observed, it means that there is no mineral oil in the food.The combination of TLC can further reduce the detection limit, and further improve the sensitivity and accuracy.This method is simple in operation and low in cost, but it is not suitable for vigorously promoting due to various reasons, but it is still a method for qualitative analysis of mineral oil content in food in laboratory research.[3]
2) Gas chromatography
Gas chromatographyIt is a method of separating the mixture by using the volatility of the tested substance or the difference of boiling point. The spectrum of gas chromatography is based on the molecular weight of mineral oil or the order of carbon atom number from low to high. The internal standard or external standard is used for quantitative determination of the tested substance, and the qualitative analysis is carried out by comparing the spectrum of gas chromatography with the standard sample.This method has many advantages, such as less sample loss, simple operation and fast reaction speed. It is suitable for research in large enterprises and advanced scientific research institutes.[3]
In addition, due to theHydrogen flame ionization detector(FID) has high accuracy and good repeatability, so this kind of detector is often used in the determination of mineral oil in food. However, this method has the disadvantages of poor selectivity and sensitivity, and high detection limit, which means that it can only be detected when the content of mineral oil reaches a certain level. If the content of mineral oil is small, it may not be detected.Therefore, people often use various methods to pretreat samples to improve the enrichment ability of mineral oil.High performance liquid chromatography gas chromatography hydrogen flame ionization detector (HPLC-GC-FID) is a widely used method at present, but only a few laboratories have such equipment because of its high price and maintenance costs.[3]
3) Two dimensional gas chromatography (GC × GC)
In order to make up for some shortcomings of one-dimensional gas chromatography, two-dimensional gas chromatography has been gradually used in the detection of mineral oil in food in recent years.This method can separate the components in the mineral oil more thoroughly. It can not only separate the MOSH from the MOAH, but also separate the mineral oil according to the structure of the MOSH and the number of rings in the MOAH. After this separation, a series of analysis can be carried out on the pollution source of the mineral oil.[3]
In the first dimension separation of GC × GC, non-polar stationary phase is usually separated according to the difference of boiling point;In the second dimension, polar column is used to further separate mineral oil with the same boiling point, and this method can be used to determine mineral oil in food.[3]
4) Gas chromatography-mass spectrometry
Gas chromatography-mass spectrometry (GC-MS) is a method that combines the advantages of gas chromatography and mass spectrometry, and can easily and accurately determine whether there are hydrocarbon compounds (mineral oil) in grain and oil. This method is also one of the most accurate methods to detect whether there is mineral oil in food.The content of mineral oil can be qualitatively analyzed by using this method to detect the sample and then simply treat the sample.Compared with other methods, this method has the advantages of high sensitivity, small sample loss, accurate results and high recovery rate, but its disadvantages are high cost, long time consumption and harsh conditions.[3]
5) Two dimensional gas chromatography-mass spectrometry (GC × GC-MS)
The traditional one-dimensional gas chromatography-mass spectrometry (GC-MS) can not only be used as a common tool for crude oil analysis, but also widely used in the determination of mineral oil in food. However, its resolution and peak capacity are low, and the separation effect of mineral oil in food is not ideal, affecting the accuracy of test results.Compared with the traditional one-dimensional gas chromatography, two-dimensional gas chromatography-mass spectrometry has higher sensitivity, accuracy and lower detection limit, and has a broader application prospect, but it is expensive and costly.[3]
Agricultural applications
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Application History
In the first century AD, Pliny the Elder described the examples of non pesticide protection of plants with mineral oil in his Natural History.In the 17th century, there were instances of applying kerosene directly on citrus trees to control scale insects.In the 18th century, people mixed 15% (mass fraction) of kerosene with soapy water to make emulsion for pesticide use.At the beginning of the 20th century, people began to study the mechanism of mineral oil to control insect pests. It was believed that the 250~400 ℃ fraction of mineral oil was more effective than kerosene;Modern pest control experts believe that the heavier 320~400 ℃ distillate mineral oil has better control effect.Recent research shows that mineral oil with narrow distillation range (30~50 ℃) has the possibility to optimize the efficacy and reduce the harm.[4]
Although the use of chemical synthetic fertilizers and pesticides is prohibited in organic agriculture, it is allowed to use some of the organic food production standardsPesticide of mineral origin。In 1999, byInternational Food and Agriculture Organization(FAO) andworld health organizationIn the "Guide to Organic Food Production" issued by WHO, agricultural mineral oil is listed as a pesticide that can be used after certification.The National Organic Food Standards Board (NOSB) of the United States listed agricultural mineral oil as a pesticide recommended for use in organic food production.According to the No.4 standard (MRL standard) of the Food Standards Code of Australia and New Zealand, namely the MRL standard, paraffin oil and mineral oil are exempted from MRL requirements.The National Sustainable Agriculture Association of Australia (NASAA), as the countryOrganic food certificationAmong the 11 listed organic food production, the plant protection pesticides allowed to be used also include agricultural mineral oil.Petroleum mineral pesticides are also one of the three types of pesticides (biological pesticides, mineral pesticides and organic synthetic pesticides) allowed to be used in the Guidelines for the Use of Pesticides in Green Food Production (NY/T 393-2013) implemented on April 1, 2014.[4]
Insecticidal mechanism
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As a mineral pesticide, the insecticidal mechanism of mineral oil is physical suffocation and behavior change, and the bactericidal mechanism is interference.[4]
Physical asphyxia
The physical suffocation of mineral oil kills insects by spraying, which makes the mineral oil form an oil film on the surface of the insect body or egg shell, and enter the valve and trachea of larvae, pupae and adults through capillary action, so as to suffocate the insect pests to death;The purpose of killing eggs is achieved by penetrating the egg shell and interfering with the metabolism and respiratory system of eggs.[4]
Physical asphyxiation is ideal for killing small fixed and slow moving insects (such as mites, scale insects, some aphids and whiteflies);Egg killing is of great value for the control of outbreaks of pests such as Bemisia tabaci, whitefly and diamondback moth.[4]
Behavior change
Phytophagous insects and mites usually use antennae, mouthparts, feet or abdominal sensory organs to detect plant chemicals, so as to identify specific host plants that can feed and lay eggs.Mineral oil film can seal the sensory organs of pests and prevent them from finding hosts;At the same time, a protective film can also be formed on the surface of plants, thus reducing the feeding and oviposition capacity of pests, and even changing their mating behavior, directly reducing the population of pests and protecting crops.[4]
Interference effect
As a bactericide, mineral oil can destroy the cell wall of bacteria, interfere with their respiration, and interfere with the attachment of pathogens to host plants;It can also control mycelium and prevent spore germination and infection.For example, in the prevention and treatment of powdery mildew, mineral oil can cause the death of powdery mildew spores by the most basic physical contact, which has the effect of eradication and protection.[4]
Insecticidal characteristics of mineral oil
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It can be seen from the insecticidal mechanism of mineral oil that compared with chemical synthetic pesticides, its insecticidal effect has the following characteristics:[4]
Broad-spectrum
Mineral oil is effective to a variety of crop pests, and is suitable for pest control in different seasons, so it is widely applicable.[4]
Very low toxicity
Mineral oil comes from petroleum. Compared with chemical synthetic pesticides, mineral oil has almost no chemical change under normal conditions, so its biological toxicity is far lower than that of chemical pesticides, even non-toxic.[4]
Low dosage and low residue
Based on the insect killing mechanism of film-forming asphyxiation, the goal can be achieved with extremely thin mineral oil film, so the dosage is low and the residue is low.[4]
Long term effectiveness
Mineral oil film is effective for the whole life cycle of pests, and can prevent the hatching of first eggs and the movement of nymphs, so it has a long lasting effect.[4]
No drug resistance
A prominent problem in the use of chemical insecticides is that the interval between pests producing resistance to pesticides is getting shorter and shorter, which makes the pesticides ineffective;Mineral oil is based on physical insecticidal effect, and pests will not have resistance to it.[4]
Harmless to natural enemies
Mineral oil has low lethality to natural enemies.[4]
Ideal properties of mineral oil pesticides available for agriculture
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Relationship between physical and chemical properties of mineral oil and agricultural production Traditionally, mineral oil refers to liquid hydrocarbon mixture extracted from petroleum by appropriate process, and its basic physical and chemical properties generally include: composition, distillation range, density, kinematic viscosity, flash point, impurity content, etc.In agricultural production, various performance indicators of mineral oil have different impacts on crops.[4]
form
The composition of mineral oil can be characterized in two forms, namely, group composition and structural composition.The group composition includes alkanes, cycloalkanes and aromatics;The structural composition is characterized by CA (the percentage of aromatic carbon atoms in total carbon atoms), CN (the percentage of cycloalkane carbon atoms in total carbon atoms), and CP (the percentage of alkane carbon atoms in total carbon atoms).[4]
Alkanes are the main components that affect the insecticidal effect, and they have a decisive impact on the safety of mineral oil on crops, environmental safety and insecticidal effect.Therefore, the mineral oil should have a high content of paraffins, that is, the higher the CP value, the better;With the increase of the carbon atom number of alkanes, the insecticidal effect increases, but when the carbon atom number is greater than 25, the risk of pesticide damage increases.The carbon number of alkane with the best insecticidal effect is Ctwenty～Ctwenty-five。[4]
Cycloalkanes have low insecticidal activity and risk of drug damage, so the lower the CN value, the better.The toxicity and carcinogenicity of aromatic hydrocarbons have been confirmed, so the CA value should be as low as possible.In fact, de aromatic mineral oil is the most ideal choice.[4]
Distillation range
Distillation range reflects the safety and insecticidal effect of mineral oil on crops.Generally, the temperature difference between 10% and 90% distillation point is used to characterize the safety of mineral oil to crops.Experience shows that when the temperature difference is less than 40 ℃, the mineral oil is stable, less harmful and safe for crops;The carbon number of 50% distillate point represents the type and effect of mineral oil against insects.[4]
Kinematic viscosity
The appropriate kinematic viscosity is conducive to the direct atomization or emulsification of mineral oil, and also determines the spread and adhesion of the spray oil film, which has an impact on the dosage, residual amount and long-term effectiveness.[4]
impurity
Impurities refer to non chain alkanes and heteroatomic compounds.The carcinogenicity of aromatic hydrocarbons has been proved;Aromatic hydrocarbons and other unsaturated hydrocarbons are easy to form acid substances in the atmosphere that may cause crop damage;Sulfur compounds can cause pollution and harm.Therefore, low sulfur and low aromatics are necessary requirements for available mineral oil pesticides.[4]
Physical and chemical properties
The flash point, freezing point, density and other physical and chemical properties are the safety and performance requirements of the oil itself.The requirements of organic agriculture on the physical and chemical properties of mineral oil, as the mineral oil of pesticide available for organic agriculture, should not only meet the insecticidal function, but also be safe for people, livestock and the environment, and meet the requirements of organic food production standards.[4]
In view of the different uses of mineral oil as pesticide, FAO formulated quality control indicators and detection methods in 1971.Developed countries also set requirements for the product quality of agricultural mineral oil to ensure its use safety.With the continuous development of mineral oil refining technology, the quality requirements of agricultural mineral oil are also increasing.[4]
Application prospect of organic agriculture
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With the development of petrochemical production technology, the production of targeted narrow distillate products through precision distillation technology has been realized;The technology of deep removal of sulfur, nitrogen, aromatics and other toxic substances through appropriate hydrogenation technology instead of traditional sulfonation process is mature.Therefore, it is completely possible for mineral oil to meet the requirements of biosafety and organic food production standards.[4]
Mineral pesticides are low-risk natural pesticides, which can effectively reduce the use of synthetic chemical pesticides.Mineral oil that meets the requirements of organic food production standards has lower toxicity, is more friendly to the environment, and is safer to people, animals, and the environment. It is an ideal agent for the sustainable control of organic agricultural diseases and pests, and will also become a new direction of pesticide development in the 21st century.[4]
Recycling of waste mineral oil
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At present, there are two widely used waste mineral oil recovery technologies abroad, one is catalytic hydrogenation technology, the other is solvent refining combination technology. Both of these technologies have the characteristics of high recovery efficiency, good environmental protection effect, and high recovery rate. However, due to the high technical requirements for the application of these two technologies, the large volume of equipment required and the large capital investment requirements,Due to the great dependence on the stability of the source of waste mineral oil, it is not widely used in the recycling industry of waste mineral oil in China.As the distribution of enterprises producing waste mineral oil in China's petrochemical and metal production units is not centralized enough, there is no centralized source of waste mineral oil, and the collection and transportation operations will consume a lot of costs. In addition, there are many small-scale illegal waste mineral oil collection enterprises in some provinces,This has impacted the stability of the normal order of the waste mineral oil recovery and utilization market. These illegal enterprises will not only raise the price to seize the waste mineral oil resources, but also carry out vicious competition against regular enterprises, bringing chaos to the waste mineral oil recovery and utilization industry.At present, there are three types of technologies commonly used in waste mineral oil recovery and utilization enterprises: atmospheric distillation technology, vacuum distillation technology and simple pretreatment technology.[5]
Simple pretreatment technology of waste mineral oil
This method has simple technical requirements. It is only applicable to the mineral waste oil used in device lubrication and production equipment cleaning. This is because the operating conditions for equipment cleaning and device lubrication are usually closed, and the effective pollution is small. The pollutants in the waste oil are usually some mechanical wear residues and moisture,After simple filtration, decoloration and dehydration, poor quality base mineral oil can be obtained. Some waste mineral oil recovery production units also mix good quality mineral oil and solvent into the treated waste oil, so as to improve the quality of recycled oil.[5]
Atmospheric distillation of waste mineral oil
The process of application of this technology is to first heat the waste mineral oil to a certain temperature so that its components can be vaporized into steam, and then enter the condensing equipment to cool the production of base oil under the action of the condensing equipment, which is also a widely used method in the waste mineral oil treatment industry.[5]
Vacuum distillation of waste mineral oil
Distillation process is a process technology widely used in oil production. It can accurately cut the components in oil products. In the waste mineral oil recycling industry, the application of vacuum distillation technology can recover more than half of the oil.The vacuum distillation process uses additives to neutralize and remove the acidic substances in the waste mineral oil, and filter the ash and metal slag. Then, the water and light components in the waste mineral oil such as light oil are separated by vacuum evaporation. Other raw materials are sent to the vacuum distillation tower for separation. The temperature of the vacuum distillation tower decreases from bottom to top,It is cut into several lubricating base oil components according to the distillation range of oil products.[5]
