Primary Refinery Operations

Here we consider the refinery production of petrochemical feedstocks. Downstream refinery processes will only be discussed as it applies to the quality of these feeds. 

Crude oil enters the refinery and is stored and excess salt removed prior to distillation. Often several different crude oils are co-mingled before distillation in the atmospheric distillation tower. This has the duty to separate the crude oil into fractions according to distillation range. 

Boiling higher than naphtha is the kerosene fraction, boiling typically 190 C to 230°C. This fraction is used for the production of jet- 

The next boiling fractions are the gas-oils, which in the refinery context are used to produce diesel. In the atmospheric column, the boiling point of the heaviest fraction is about 360°C. 

A point of note is that refiners, in meeting the various fuel specifications, have some flexibility in the distillation cut points and often change these on a regular basis. This helps the refiner to better match the output of the column to the demands of the transport fuel market. For example, if the refiner is faced with an increase in demand 

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We believe to have shown here that the RVP of gasoline is a primary characteristic for quality resulting from a delicate compromise between the demands for vehicle performance, optimization of refinery operations and environmental protection. 

The continued use of atmospheric and vacuum distillation has been a major part of refinery operations during this century and no doubt will continue to be employed, at least into the beginning of the twenty-first century, as the primary refining operation. 

The primary processes of a refinery operation are illustrated in Figure 4.1. 

The function of a heat exchanger as the name implies, is to transfer heat energy between streams. The prime reason for this is to conserve heat which is usually a costly component of any process. Reduced efficiency has to be compensated in some way in the process. If heat is not recovered the shortfall will have to be made up perhaps by the consumption of more primary fuel such as oil, coal or gas. In other operations it is necessary to raise the temperature of a particular stream to facilitate a chemical reaction, for example hydrocracking in refinery operations to produce lower molecular weight products. In power stations the efficiency of the steam condensers at the outlet from the turbines has a direct effect on the cost of... 

The operations in the Mt. Isa primary refinery have been covered by previous papers (2,6). The Mt. Isa bullion is produced by a conventional sinter plant/lead blast furnace operation. The resulting crude bullion is decopperised to less than 0.003 % Cu and is then given a caustic soda treatment to remove arsenic to less than 0.003%, prior to casting into 4-tonne slabs. This impure lead is shipped by railroad to Townsville and then by sea in 12,000- to 14,000-tonne shipments to BRM for further processing. 

The terms cracking and reforming are often used without qualification to describe a variety of refinery and primary petrochemical operations. It is hoped... 

Crude oil primary field operations include activities occurring at or near the well-head and before the point where the oil is transferred from an individual field facility or a centrally located facility to a carrier for transport to a refinery or a refiner. 

De-silvering is not normally required as it is in the processing of primary bullion, where silver is an important element in lead concentrates. The de-bismuthising operation is less common than at primary refineries, but this depends entirely on the bismuth content of scrapped and recycled lead and will reflect the quality of lead consumed some years previously. In the USA, for instance, the bismuth content of secondary pure lead has been declining since the early 1970s. Most of the primary lead produced in the USA from domestic concentrates has been bismuth-ftee since 1970 and a slow decrease in the recirculating bismuth content of recycled lead has occurred since then. Prior to 1980, the presence of significant amounts of bismuth restricted the overall purity of recycled lead to 99.96 per cent, or less recyclers can now routinely produce lead of 99.99 per cent purity, or more. 

All the previous studies involve a uniform feedstock composition. In practice, however, feed composition can change significantly over the course of regular refinery operation (see Figure 5.18). So, it is important to study changes in product distribution when the feed composition varies. The benzene content of reformate is of particular interest to refiners. Recent regulations have imposed strict limits on the amount of benzene present in the gasoline pool. Since the reformer is the primary source of benzene, we look for ways to reduce the benzene in reformate. 

The principal U.S. lead producers, ASARCO Inc. and The Doe Run Co., account for 75% of domestic mine production and 100% of primary lead production. Both companies employ sintering/blast furnace operations at their smelters and pyrometaHurgical methods in their refineries. Domestic mine production in 1992 accounted for over 90% of the U.S. primary lead production the balance originated from the smelting of imported ores and concentrates. 

Fluid eatalytie eraeking (FCC) is eonsidered tlie primary eonversion proeess in an integrated refinery. For many refiners, the eat eraeker is tlie key to profitability beeause sueeessful operation of tlie unit ean determine whether or not a refiner stays in business and remains eompetitive. 

Although numerous cases have been documented where petroleum refineries have simultaneously reduced pollution outputs and operating costs through pollution prevention techniques, there are often barriers to their im-plementation. The primary barrier to most pollution prevention projects is cost. Many pollution prevention options simply do not pay for themselves, or the economics often appear marginal. Corporate investments typically must earn an adequate return on invested capital for the shareholders and some pollution prevention options at some facilities may not meet the requirements set by company policies. 

There is a wide range of conversion levels. The term maximum conversion type has no precise definition but is often used to describe a level of conversion, where there is no net fuel oil manufactured. A fuel products refinery with specialities may manufacture lubricating oils, asphalts, greases, solvents, waxes and chemical feed stocks in addition to the primary fuel products. The number and diversity of products will naturally vary from one refinery to another. Refineries produce chemical feed stocks for sale to the chemical affiliates and do not have responsibility for the manufacture of chemical products directly. Both operations may be carried out at the same physical location but the corporate product responsibilities are usually separate. 

Fluid catalytic cracking (FCC) continues to play a key role in an integrated refinery as the primary conversion process. For many refiners, the cat cracker is the key to profitability in that the successful operation of the unit determines whether or not the refiner can remain competitive in today s market. 

In 1996, the U S. domestic lead industry was comprised of 17 mines located primarily in Alaska, Colorado, Idaho, Missouri, and Montana two primary smelter-refineries in Missouri a primary smelter in Montana and 25 secondary (recycling) producers operating 31 plants. Of the lead recycled in 1996, 99% was produced by 10 companies operating 17 plants in Alabama, California, Florida, Georgia, Indiana, Louisiana, Minnesota, Missouri, New York, Pennsylvania, Tennessee, and Texas. Lead is also sold by the Defense National Stockpile Center (DNSC) as a result of legislation passed in 1992 authorizing the disposal of the entire 545,000 metric tons in the stockpile over several years. The law, however, requires the task to be completed without undue disruption of commercial lead markets (Larrabee 1997 Smith 1998). 

By approaching the refinery design from a crude oil perspective, the advantage of preseparation by stepwise condensation after HTFT synthesis was reduced. The refinery design included primary separation steps typically found in crude oil refineries, namely, an atmospheric distillation unit (ADU) that is followed by a vacuum distillation unit (VDU). Despite the design intent, the operation of these units, out of necessity, had to be different. The reboiler temperature of the ADU was... 

Air emissions from a petroleum distillation unit include emissions from the combustion of fuels in process heaters and boilers, fugitive emissions of volatile constituents in the crude oil and fractions, and emissions from process vents. The primary source of emissions is combustion of fuels in the crude preheat furnace and in boilers that produce steam for process heat and stripping. When operating in an optimum condition and burning cleaner fuels (e.g., natural gas, refinery gas), these heating units create relatively low emissions of sulfur oxides, (SO c), nitrogen oxides (NO c), carbon monoxide (CO), hydrogen sulfide (H2S), particulate... 

In addition to those from the fundamental processes, wastewaters are also generated from other auxiliary operations in refineries. Figure 7 shows the various sources of wastewater and their primary pollutants in a refinery [17]. 

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