Refinery application

In addition to the distillation of crude oil coming into the refinery, stills of various designs are used in other types of service throughout the refinery. 

Cracked products are separated in distillation equipment which is very similar to an atmospheric crude pipe still. The principal difference is that these products are hot from the cracking operation, so that a fired heater is not required. 

Catalytic cracking units operate at low pressure, and the primary fractionator 

The vapors are superheated and must be cooled about 200°F before an appreciable amount of liquid can be condensed. 

The vapors from a fluid catalyst unit carry a small amount of fine catalyst particles which might clog the narrow clearances of a conventional bubble cap plate. 

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Fractionator-feed preheaters partially vaporize charge stock from an upstream unfired preheater en route to a fractionating column. A typical refinery application a crude feed to an atmospheric column enters the fired heater as a liquid at 505 K (450°F) and leaves at 644 K (700°F), having become 60 percent vaporized. 

A common type of distillation contacting device used in refinery applications is the sieve tray. In the early 50 s and for many years before, the bubble cap tray was the mainstay of the distillation field. A sieve tray consists of a flat plate with regularly spaced holes, normally 1/2 to 1 inch in diameter. Liquid flows horizontally across the tray and into a channel, called a downcomer, which leads to the tray below. The sieve tray exhibits good capacity, excellent efficiency, low pressure drop, and good flexibility i.e., it will operate quite efficiently at tower loadings which are 1/2 to 1/3 of design values. 

Other designs of ground flares suitable for refinery application are available. In some of these cases, noise is appreciable, in comparison with the multijet type, but their compact size, low space requirement, simplicity, and hence low cost, may give an overall advantage. 

Hazard. Specify explosion-proof and always class and group (i.e.. Class 1 Group D for most petroleum refinery applications). 

The advantages of this type of monitor are that it can be automated to produce print-outs of corrosion rate at regular intervals and that it can be used to monitor corrosion in any type of corrodent, e.g. gaseous, non-ionic liquid or ionic electrolyte. Such monitors are in wide use, especially in refinery applications. 

Fully commercial In natural gas and refinery applications. Feed impurities In gases from synfuel plants can create problems... 

Table I. Refinery Applications of Fluid Catalytic Cracking in Processing Typical U. S.

Naphthenic acid corrosion has been a problem in petroleum-refining operations since the early 1990s. Refineries processing highly naphthenic crudes must use steel alloys 316 stainless steel is the material of choice. Conversely, naphthenic acid derivatives find use as corrosion inhibitors in oil-well and petroleum refinery applications. 

The first application of pervaporation was the removal of water from an azeotropic mixture of water and ethanol. By definition, the evaporative separation term /3evap for an azeotropic mixture is 1 because, at the azeotropic concentration, the vapor and the liquid phases have the same composition. Thus, the 200- to 500-fold separation achieved by pervaporation membranes in ethanol dehydration is due entirely to the selectivity of the membrane, which is much more permeable to water than to ethanol. This ability to achieve a large separation where distillation fails is why pervaporation is also being considered for the separation of aromatic/aliphatic mixtures in oil refinery applications. The evaporation separation term in these closely boiling mixtures is again close to 1, but a substantial separation is achieved due to the greater permeability of the membrane to the aromatic components. 

Refinery applications have always been outside the scope of the NACE MR0175. However, this standard has frequently been used as a reference - NACE MR0175 has always been a little over the top for refinery use Sulphide couosion cracking is not such a concern downstteam (refineries have reduced chloride levels). Therefore, NACE decided to formulate a new refinery-specific standard inclusive of sulphide couosion cracking to meet the specific needs of the oil refining industry. 

In oil and gas refinery applications, titanium is used as protection in environments of H2S, S02, C02, NH3, caustic solutions, steam, and cooling water. It is used in heat-exchanger condensers for the fractional condensation of crude hydrocarbons, NH3, propane, and desulfurization products using seawater or brackish water for cooling. 

This source of hydrogen is being effectively utilized with the aid of the cryogenic hydrogen upgrader to recover and purify hydrogen for return to such refinery applications as residuum hydrocracking and hydrodesulfurization. 

Johnson, H.E., and B.L. Schulman, 1993, Assessment of the potential for refinery applications of inorganic membrane technology an identification and screening analysis, U.S. Department of Energy Final Report under Contract No. DE-ACOl-88FE61680(Task 23). 

Chemical Methods. The most common method of emulsion resolution in both oil-field and refinery applications is a combination of heat and application of chemicals designed to eliminate or neutralize the effects of emulsifying agents. Addition of suitable chemicals with demulsifying properties specific to the crude oil to be treated will generally provide quick, cost-effective, and flexible resolution of emulsions. Success of chemical demulsifying methods is dependent upon the following ... 

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