Refinery equipment

The stability of the stock with respect to heat determines the maximum temperature which can be employed in the distillation process. The complexity of the process is also affected by the product purity demanded by product specifications or by the limitations of subsequent processing equipment. The relative values of the several products determine how much money can be spent in designing the unit for increased yields of the more valuable products. 

The temperature at which the crude enters the tower is usually determined by one of the following considerations  

In single-stage units which do not produce kerosene or other critical stocks, flash zone temperatures may be as high as 750°-775°F. The principal limitation is the point at which cracking of distillates to less valuable gas or the rate of coke formation in the furnace tubes becomes excessive. 

In two stage units, it is often economical to distill more gas oil in the vacuum stage and less in the atmospheric stage than the maximum attainable. 

Gas formed in the atmospheric tower bottoms piping at high temperatures tends to overload the vacuum system and thereby to reduce the capacity of the vacuum tower. 

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Naphthenic acids have been the topic of numerous studies extending over many years. Originally recovered from the petroleum distillates to minimise corrosion of refinery equipment, they have found wide use as articles of commerce in metal naphthenates and other derivatives. A comprehensive overview of the uses of naphthenic acid and its derivatives can be found in References 1 and 2. A review of the extensive research on carboxyUc acids in petroleum conducted up to 1955 is available (3), as is a more recent review of purification, identification, and uses of naphthenic acid (4). 

Bonner, W. A., et al Prevention of Hydrogen Attack on Steel in Refinery Equipment," paper presented at API Div. of Refining 18th Mid-year Meeting, May 1953. 

Heller, J. J. Corrosion of Refinery Equipment by Naphthenic Acid, Report of Technical Committee T-8, NACE, Materials Protection, Sept. 1963, p. 90. 

Geerlings, H. G., and J. C. Jongebreuer. Corrosion in Oil Refinery Equipment, paper presented at the 1st International Congress on Metallic Corrosion, London, 1961. 

This section discusses the principal causes of overpressure in refinery equipment and describes design procedures for minimizing the effects of these causes. Overpressure is the result of an unbalance or disruption of the normal flows of material and energy that cause material or energy, or both, to build up in some part of the system. Analysis of the causes and magnitudes of overpressure is, therefore a special and complex study of material and energy balances in a process system. 

Chapter II Guide for Inspection of Refinery Equipment—Conditions Causing Deterioration or Failures... 

From adsorption analysis data, it is possible to calculate theoretical yields of deoiled wax, asphalt, resins, and solvent extraction yields of waxy raffinate. Nearly 100 different stocks have been so evaluated by California Research Corp. during the past few years and many of these data have been correlated with operations in refinery equipment and with pilot plant operations. 

A mathematical procedure for the design of fractionating towers developed by Sorel (54) in 1893 had little acceptance by the petroleum industry because it was based on treatment of binary mixtures, such as alcohol and water the required vapor-liquid data on petroleum products were in general not available the calculations were laborious the original publication was in French and not widely available to American industry and the builders of refinery equipment were seldom staffed to use the procedure. 

Sulfttr Content. The amount of sulfur in crude is important in terms of handling the crude within the refinery and the undesirable effects of sulfur in finished products. High-sulfur crudes require special materials of construction for refinery equipment because of their corrosiveness. Certain refinery processes require desulfurization of sour charge stocks prior to use as a feedstock, not only because of their corrosiveness, but also because of the effect of sulfur-bearing compounds on expensive catalysts, From the standpoint of the consumer, sulfurous gasoline has an unforgettably offensive odor unless specially sweetened and it may corrode the fuel system and engine parts, as well as pollute the atmosphere after it has been burned,... 

Battery a series of stills or other refinery equipment operated as a unit. Baume gravity the specific gravity of liquids expressed as degrees on the Baume (°Be) scale for liquids lighter than water ... 

The approach of forming a team of specialists to evaluate a proposal to chemically clean refinery equipment is a concept that will be discussed in Chapter 10. This approach is excellent for developing Mechanical Integrity procedures of critical operations. 

Typical products are electric motors, electronics, transformers, valves, pumps, refinery equipment, and appliances. 

Materials selection for centrifugal pumps is contained in API 3 610, Appendixes E and F. Another source of information is API s Guide for Inspection of Refinery Equipment, Chapter II. In addition, both NACE Group Committee T-8 on Refining Industry Corrosion and the API Corrosion Committee publish minutes of their semiannual meetings. An index of Group Committee T-8 s minutes has been produced so that information on any topic discussed can be located. 

Reprinted from Corrosion of Refinery Equipment by Aqueous Hydrogen Sulfide, Corrosion, April 1959.)... 

API Standard 942. Recommended Practice for Welded, Plain Carbon Steel Refinery Equipment for Environmental Cracking Service. Washington, DC American Petroleum Institute, latest revision. 

NACE Standard RP0170, Protection of Austenitic Stainless Steel from Polythionic Acid Stress Corrosion Cracking During Shutdown of Refinery Equipment," NACE, Houston, TX, latest revision. 

Emission factors established by the EPA are frequently used to estimate total airborne emissions from different types of refinery equipment. These are called AP-42 emission factors. Most AP-42 factors do not provide information about the composition of emissions. The project s measurement program allowed for direct comparison between several measured or inferred emission rates and emissions calculated using these factors. 

In summary, imports of foreign oil should increase rapidly in this decade. Much of the oil will probably be high sulfur crude oil from the Persian Gulf. Expected modifications of the oil import program will enable the refinery equipment that will process the oil to be located domestically. This would be beneficial to national security, trade balance, and the domestic economy. The ultimate effect such modifications in the oil import program would have on domestic refinery configurations would probably be slightly beneficial to the environment. 

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