Equipment Fouling

The atmospheric bottom, also known as reduced oil, is then sent to the vacuum unit where it is further separated into vacuum gas oil and vacuum residues. Vacuum distillation improves the separation of gas oil distillates from the reduced oil at temperatures less than those at which thermal cracking would normally take place. The basic idea on which vacuum distillation operates is that, at low pressure, the boiling points of any material are reduced, allowing various hydrocarbon components in the reduced crude oil to vaporize or boil at a lower temperature. Vacuum distillation of the heavier product avoids thermal cracking and hence product loss and equipment fouling. 

Water and salts can lead to major problems such as equipment corrosion, uneven heating, and equipment fouling. 

Owing to reduced salt solubility, the formation of metal oxides and, eventually, the presence of stable solid-matter particles, these are all present in the SCWO processes. These particles can cause equipment-fouling and erosion. However the reduced solubility of salts under supercritical conditions introduces the possibility of a solid fluid separation. 

Other than the reactor system, the distillation column that separates the unconverted ethylbenzene from the crude styrene is the most important and expensive equipment in a styrene plant. To minimize yield losses and to prevent equipment fouling by polymer formation, polymerization inhibitors are used in the distillation train, product storage, and in vent gas compressors. 

Cooling towers fall under the general category of direct-contact equipment. In direct-contact equipment, fouling resistances are automatically eliminated because a surface is no longer available on which they can form. This is a unique feature because it allows direct-contact equipment to operate indefinitely without interruption in thermal performance. 

Impurities affecting the catalyst must be removed. Evaluate the cost of an extra purification system for feeds, as well as the cost of recycling harmful impurities, including equipment fouling and maintenance. 

Interactions of electromagnetic radiation with particles Transport and deposition Atmospheric visibility radiative transfer in combustors analytical chemistry of particles military applications Process equipment fouling thin-film deposition microcontamination filtration kinetic theory of rarefied gases hydrodynamics atmospheric dry and wet deposition. 

No equipment fouling even in the production of ultra-low density polyethylene... 

Since H2S and possibly other sulfur compounds rapidly reduce the chromate ion. the use of this inhibitor is uneconomical in the presence of appreciable quantities of such impurities. In addition to increasing operating costs by destroying the inhibitor, the reduction reaction results in the formation of insoluble precipitates, which cause erosion of equipment, fouling of heat exchanger surfaces, and other operating difficulties. Fortunately, H2S itself appears to... 

Proper cooUng water and boiler feed water treatments are important to minimize equipment fouling and corrosion. Seawater is occasionally used for acid cooling requiring careful material selection. 

The deposits usually accumulate in the downstream separators, heat exchangers, and fractionating towers, and foul the transfer lines, eventually causing unit shutdown. Equipment fouling by the coke-like sediments formed in residual oil hydroconversion or the hydrocracking process can lead to enormous financial burdens in terms of increased costs of operation, maintenance, and shutdown. The refiners often use chemical and mechanical treatments to remove the deposits from the equipment Some refiners use antifoulant chemical additives to the feed to suppress the formation of sediments. 

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