How to deal with sediment in machinery lubricating oil?
April 15, 2022
1. Mechanical Impurities Mechanical impurities refer to the sum of the amounts of substances in petroleum or petroleum products that are insoluble in oil and specified solvents. Such as mud sand, dust, iron filings, fibers and some insoluble salts. Mechanical impurities can be removed by methods such as precipitation or filtration. For light oil, mechanical impurities will block the oil circuit, causing rubber or corrosion; for boiler fuel, it will block the nozzle, reduce combustion efficiency, and increase fuel consumption; for lubricating oil, it will destroy the oil film, increase wear, and block oil filtration. device to promote the formation of carbon deposits, etc. Therefore, it is called mechanical impurities. Mechanical impurities come from external pollution in the production, storage and use of oil products or the wear and tear of the machinery itself. Most of them are sand, gravel and carbon deposits, as well as some organic compounds that are insoluble in solvents caused by additives. metal salts. Its determination is carried out in accordance with GB/T 511-83 Petroleum Products and Additives Mechanical Impurities Determination Method (Gravimetric Method). The process is as follows: weigh 100g of test oil and heat it to 70°C to 80°C, add 2-4 times of solvent, filter on the paper in the weighed empty bottle, wash the filter paper bottle with hot solvent and weigh again. The difference between the front and rear weights of the quantitative filter paper is the weight of the mechanical impurities, and the mass fraction of the mechanical impurities is obtained.
2. Sediment Total sediment refers to all inorganic and organic substances in the oil that are insoluble in solvents (such as toluene), and is one of the specifications of medium and heavy fuel oils. Sediments are often some mechanical impurities, or are introduced during processing, transportation, and storage. High levels of sediment can easily block filters, nozzles, valves, etc., and cause or aggravate the wear of mechanical parts. The measurement principle is that a certain amount of oil sample is placed in a porous filter and continuously dripped into a hot solvent, all components soluble in the solvent are drained through the filter, and what remains is the precipitate that is insoluble in the solvent. ,unit weight%. The measurement standard can be found in GB/T6531 or ISO 10307.
The main reasons for the appearance of precipitation and impurities in lubricating oil 1) Because of impurities existing in the equipment system before adding new oil, some impurities are often generated in new equipment and long-term equipment. Generally, the equipment is flushed with flushing oil until the impurities contained in the oil are achieve the specified target. 2) The storage, transportation and use of lubricating oil are not carried out in accordance with the specified operating requirements, resulting in the entry of impurities in these processes and affecting the quality of oil products. 3) The deposits are mainly high-viscosity engine oil with a large dosage, which will be precipitated to varying degrees at low temperatures. The deposits are not impurities generated after long-term use of the equipment, or external impurities enter the contaminated oil, so it has no effect on the normal use of the oil. Treatment of Precipitation and Impurities For the above three causes of precipitation and impurities, different treatment methods need to be taken: The treatment method of impurities existing in the equipment system itself before adding new oil: different equipment has different lubricating oil systems, some systems are large, some systems are small, no matter the size of the oil system is generally mainly composed of oil tank, oil pump, oil Cooler, oil filter and other equipment and valves, pipelines and instruments are connected with the lubrication points of the machine itself, the oil holes and oil grooves of the bearing bush, bearing box and crankcase through the pipeline to form a complex set of lubricating oil. system. New equipment: When the lubricating oil pipeline system is installed, the inside of the pipe must be kept clean, but this is not enough. The lubricating oil system of the unit should also be flushed with oil circulation. If the oil system is not clean and there is dirt in the pipe, it will affect the unit. In normal operation, the bearing bush will even be burnt out, so the long-term stable operation of the unit is guaranteed by the oil circulation flushing. Equipment used for a long time: some impurities are often generated in equipment used for a long time. Generally, the equipment is flushed with flushing oil until the impurities contained in the oil reach the specified index, and the flushing oil after flushing should be discarded or changed. do it with. If you want to use these flushing oils, you must carry out the corresponding oil analysis and test, and the cleanliness can only be used after reaching a certain standard, and it is required to strengthen filtration and cut water before use and during use.
