Petroleum industry, refining processe

Isomerization of straight-chain to branched alkanes also increases the octane number, as do alkylates produced by alkene-isoalkane alkylation (such as that of isobutane and propylene, isobutylene, etc.). These large-scale processes are by now an integral part of the petroleum industry. Refining and processing of transportation fuels became probably the largest-scale industrial operation. 

Catalytic hydrodesulfurization (HDS), the removal of sulfide in the form of H2S from petroleum, is a critical step in the industrial refinement process and one of increasing importance as the cleaner world supplies of petroleum feedstocks dwindle and the poorer quality feedstocks have to be used. The removal of sulfur (and certain other impurities such as nitrogen in hydrodenitrogenation) is undertaken using transition-metal sulfide catalysts (Weisser and Landa, 1973). The most widely used materials... 

Lubricants. Petroleum lubricants continue to be the mainstay for automotive, industrial, and process lubricants. Synthetic oils are used extensively in industry and for jet engines they, of course, are made from hydrocarbons. Since the viscosity index (a measure of the viscosity behavior of a lubricant with change in temperature) of lube oil fractions from different cmdes may vary from +140 to as low as —300, additional refining steps are needed. To improve the viscosity index (VI), lube oil fractions are subjected to solvent extraction, solvent dewaxing, solvent deasphalting, and hydrogenation. Furthermore, automotive lube oils typically contain about 12—14% additives. These additives maybe oxidation inhibitors to prevent formation of gum and varnish, corrosion inhibitors, or detergent dispersants, and viscosity index improvers. The United States consumption of lubricants is shown in Table 7. 

Several processes are available for the recovery of platinum and palladium from spent automotive or petroleum industry catalysts. These include the following. (/) Selective dissolution of the PGM from the ceramic support in aqua regia. Soluble chloro complexes of Pt, Pd, and Rh are formed, and reduction of these gives cmde PGM for further refining. (2) Dissolution of the catalyst support in sulfuric acid, in which platinum is insoluble. This... 

Catalysts for Chemical Industry Applications. The PGMs are widely used as catalysts in chemical manufacturing, petroleum (qv) refining, and electrochemical processing (qv). A number of the most important industrial products manufactured by using PGM catalysts are outlined herein. 

Process Stream Separations. Differences in adsorptivity between gases provides a means for separating components in industrial process gas streams. Activated carbon in fixed beds has been used to separate aromatic compounds from lighter vapors in petroleum refining process streams (105) and to recover gasoline components from natural and manufactured gas (106,107). 

Solvent extraction may also be used to reduce asphaltenes and metals from heavy fractions and residues before using them in catalytic cracking. The organic solvent separates the resids into demetallized oil with lower metal and asphaltene content than the feed, and asphalt with high metal content. Figure 3-2 shows the IFP deasphalting process and Table 3-2 shows the analysis of feed before and after solvent treatment. Solvent extraction is used extensively in the petroleum refining industry. Each process uses its selective solvent, but, the basic principle is the same as above. 

Petrochemical recovered oil. Organic chemical manufacturing facilities sometimes recover oil from their organic chemical industry operations. U.S. EPA excluded petrochemical recovered oil from the definition of solid waste when the facility inserts the material into the petroleum-refining process of an associated or adjacent petroleum refinery. Only petrochemical recovered oil that is hazardous because it exhibits the characteristic of ignitability or exhibits the toxicity characteristic for benzene (or both) is eligible for the exclusion. 

The Hydrocarbon Processing Industry (HPI), has traditionally been reluctant to invest capital where an immediate direct return on the investment to the company is not obvious, as would any business enterprise. Additionally financial fire losses in the petroleum and related industries were relatively small up to about the 1950 s. This was due to the small size of facilities and the relatively low value of oil and gas to the volume of production. Until 1950, a fire or explosion loss of more than 5 million U. S. Dollars had not occurred in the refining industry in the USA. Also in this period, the capital intensive offshore oil exploration and production industry were only just beginning. The use of gas was also limited early in the century. Consequentially its value was also very low. Typically production gas was immediately flared or the well was capped and considered as an uneconomical reservoir. Since gas development was limited, large vapor explosions were relatively rare and catastrophic destruction from petroleum incidents was essentially unheard of. The outlays for petroleum industry safety features were traditionally the absolute minimum required by governmental regulations. The development of loss prevention philosophies and practices were therefore not effectively developed within the industry. 

The current trend throughout the refining industry is to produce more fuel products from each barrel of petroleum and to process those products in different ways to meet product specifications for use in various (automobile, diesel, aircraft, and marine) engines. Overall, the demand for liquid fuels has expanded rapidly and demand has developed for gas oils and fuels for domestic central heating and fuel oil for power generation, as well as for hght distillates and other inputs, derived from crude oil, for the petrochemical industries. 

Fuel gas or refinery gas is produced in considerable quantities during the various refining processes and is used as fuel for the refinery itself and as an important feedstock for the petrochemical industry. Liquefied petroleum gas (LPG) is frequently used as domestic bottled gas for cooking and heating, and forms an important feedstock for the petrochemical industry. It is also used in industry for cutting metals. 

The petroleum industry, one of the world s largest industries, has four major branches [1]. The production branch explores for oil and brings it to the surface in oilfields. The transportation branch sends crude oil to refineries and delivers the refined products to consumers. The refining branch processes crude oil into useful products. The marketing branch sells and distributes the petroleum products to consumers. The subject of this chapter is the treatment of liquid wastes from the production and refining branches. 

In Chapter 2 we sketched the processes by which petroleum is refined and polyester is made from petroleum fractions and natural gas liquids. In Chapter 3 we sketched the history of the major petrochemical companies and looked at several important single-reaction systems. In this chapter we will consider the evolution of feedstocks and intermediates in the petroleum and chemical industries. 

Fixed- or packed-bed reactors refer to two-phase systems in which the reacting fluid flows through a tube filled with stationary catalyst particles or pellets (Smith, 1981). As in the case of ion-exchange and adsorption processes, fixed bed is the most frequently used operation for catalysis (Froment and Bischoff, 1990 Schmidt, 2005). Some examples in the chemical industry are steam reforming, the synthesis of sulfuric acid, ammonia, and methanol, and petroleum refining processes such as catalytic reforming, isomerization, and hydrocracking (Froment and Bischoff, 1990). 

Butane is extracted from natural gas and is also obtained during petroleum refining. Butane can be obtained from natural gas by compression, adsorption, or absorption. All three processes were used in the early days of the LPG industry, but compression and adsorption were generally phased out during the 20th century. Most butane now is obtained from absorption and separation from oil. Very little butane is obtained from distillation. Gas stream from cracking units in the refining process contain appreciable amounts of... 

Solvent extraction is used extensively in the petroleum industry to refine lubricating oils, kerosene, and specialty oils for medicinal and agricultural purposes. It is a process that separates hydrocarbons into two phases—a raffinate which contains substances of high hydrogen to carbon ratio and an extract which contains substances of low hydrogen to carbon ratio. 

When an alkene is used in the alkylation of arenes, metal halides with hydrogen halide or water as cocatalyst, protic acids, and acidic oxides can be used as catalysts. Both linear and cyclic alkenes are used in alkylations. Alkylation with alkenes is usually preferred in industry because the processes are simpler and olefins are readily and cheaply available in pure form from petroleum refining processes. 

Bitumen describes a black or dark brown masticlike material that is thermoplastic in nature and softens upon heating. The sources of bitumen are petroleum or coal deposits. The natural product is commonly called gilsonite or pitch, a mineral formed by an old weathered petroleum flow at the surface of the earth that has left behind the larger molecules from the petroleum. A principal source in the past has been Lake Trinidad, a 445,000 m2 deposit on the island of Trinidad. Bitumen from petroleum or crude oil is called asphalt (qv). It is the material left behind after all the valuable compounds, eg, gasolines, have been distilled out of the cmde oil. The amount and quality of asphalt is dependent on the source of the crude oil used in the refining process. Some cmde oils have a higher content of asphaltic bitumen left after the distillation process. Bitumen from coal is coal-tar pitch. It remains after the valuable coal oils and tars have been distilled out of the coal tars produced by distractive distillation. Most industrial applications for bitumen products use asphalt or coal-tar pitch because the supply is more uniform and plentiful. 

These starting values are used as initial guesses for fitting the model to industrial data and the preexponential factors are changed to obtain the best fit. This is done because the kinetic parameters depend upon the specific characteristics of the catalyst and of the gas oil feedstock. This complexity is caused by the inherent difficulties with accurate modeling of petroleum refining processes in contradistinction to petrochemical processes. These difficulties will be discussed in more details later. They are clearly related to our use of pseudocomponents. But this is the only realistic approach available to-date for such complex mixtures. 

---