Filter clogging

Hydrolysis is a significant threat to phosphate ester stabiHty as moisture tends to cause reversion first to a monoacid of the phosphate ester ia an autocatalytic reaction. In turn, the fluid acidity can lead to corrosion, fluid gelation, and clogged filters. Moisture control and filtration with Fuller s earth, activated alumina, and ion-exchange resias are commonly used to minimise hydrolysis. Toxicity questions have been minimised ia current fluids by avoiding triorthocresyl phosphate which was present ia earlier natural fluids (38). 

Severe cavitation damage on the suction side of the pump reveals insufficient water supply to the pump (insufficient net-positive suction head). Such a circumstance could be caused by partially clogged filters or screens upstream of the pump, or simply by insufficient feed of water to the pump. 

Vaporization Operation / Design Vaporization (inadequate NPSHa) is the result of something that happens in the suction side of the pump, strangled valve, clogged filter, inadequate submergence. 

Internal Re-circulation Operation / Design / Maintenance Internal Re-circulation results from something in the discharge side of the pump strangled valve, clogged filter, over-pressurized header, check-valve installed backwards. 

This would be induced or caused by operation, if the plant operators strangle valves to control production tlow. Any other discharge flow restriction (clogged filter, pipe obstruction, or tin-calibrated automatic valve) would produce the same evidence. Talk with the plant engineer about this situation and show him the evidence on the pump. 

The tarry by-products clog filter paper immediately a small quantity of filter aid may be used to promote the filtration. If the condensation has been satisfactory only a small amount of material will be retained, and this step may be omitted. Occasionally a considerable amount of lumpy, tarry material is removed filtration is then more difficult, and the yield is lower. The tar, on distillation, yields no coumarin. 

Functional characteristics of the employees. The wearing of respiratory devices, except for simple dust masks, can be both physically and psychologically demanding. Even a cartridge respirator without any requirement for a hose connection can be restrictive, the more so in the presence of any obstruction to breathing by a clogged filter. Indeed, to some sus-... 

The major challenge in gasification is to avoid the formation of tars, which have a tendency to clog filters and condense in end-pipelines. Tars are considered as the condensable fraction of the organic gasification products, and consist mainly of different aromatic hydrocarbons with benzene as the main species. For removal of tars three types of catalysts have been widely investigated alkali metal salts, alkaline earth metal oxides and supported metallic oxides. 

The filtering and washing are particularity troublesome. A clogged filter will disrupt the production line and may be difficult to fix in a safe way. 

In case of pilot valves, check for any obstructions in the supply piping to the pilot or clogged filters Remove obstructions and clean filters. 

High-turbidity samples can clog filters reducing the effective pore size. To avoid this, glass fibre pre-filters should be used and clogged filters changed regularly. 

The exact temperature at which the cloud point is reached depends on the total n-alkane content of the fuel, the average size of the n-alkane molecules, their size distribution and chain structure (e.g. degree of branching). Conventional diesels contain as much as 20% of long-chain n-alkanes of limited solubility in the fuel. Pyrolysis-diesels from PE feedstocks can contain more than 40% long-chain n-alkanes. Paraffins crystallize at low temperature into very thin rhombic plates which can clog filters, transfer lines, and pumps, and can lead to engine failure at low temperatures. 

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