Petroleum Fluids in the Refining Industry

Applied Thermodynamics for Petroleum Fluids in the Refining Industry... 

Petroleum engineers are traditionally involved in activities known in the oil industry as the front end of the petroleum fuel cycle (petroleum is either liquid or gaseous hydrocarbons derived from natural deposits—reservoirs—in the earth). These front end activities are namely exploration (locating and proving out the new geological provinces with petroleum reservoirs that may be exploited in the future), and development (the systematic drilling, well completion, and production of economically producible reservoirs). Once the raw petroleum fluids (e.g., crude oil and natural gas) have been produced from the earth, the back end of the fuel cycle takes the produced raw petroleum fluids and refines the.se fluids into useful products. 

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). 

As catalysts, zeolites have found their most important application in petroleum refining processes. Their acid function is used in Fluid Catalytic Cracking (FCC), in hydroisomerisation of light alkane fraction as well as in ohgomerisation and isomerisation steps to upgrade the hquid fuels into gasohne and diesel. The combination of two different zeolites in the same industrial process is illustrated in the Shell-UOP TIP process an acidic zeolite, MOR, is used for isomerisation and the neutral LTA is used as molecular sieve for separation as shown in the scheme below (Figure 5.3). 

In the petrochemical industry, fluidized beds are used in the production of polyethylene and polypropylene, and in the petroleum refining industry, they are used in fluid catalytic cracking (FCC). 

Chlorinated ethanes are chemical compounds of the general structure C2HxCl x(X 5) and are widely used in the industrial world as solvents, chemical intermediates, cleaning fluids, fumigants, and for numerous other purposes including uses in petroleum-refining. Likewise,.the chemicals in the class of compounds known as polychlorinated biphenyls Cl (2< < 10) (PCBs) have... 

The use and application of thermodynamics of petroleum fluids encompasses all facets of the petroleum industry, ranging from production and refining of crude oil to processing of petrochemicals. This chapter is limited to a review of the most widely used thermodynamic methods in the petroleum refining industry, together with a discussion on a few recent developments. The chapter provides a single source of easily accessible relevant information. 

Density or the pressure-volume-temperature (P-V-T) relationship is considered along with enthalpy and vapour-liquid equilibria as the three most essential thermophysical properties in the petroleum refining industry. The compressibility or density is commonly used in the petroleum industry to determine the volumetric properties of gases and liquids, information that is vital for transportation, safety and sale of petroleum fluids. 

FCC. (1) Abbreviation for Food Chemicals Codex, a publication giving specifications and test methods for chemicals used in foods. (2) Abbreviation for fluid-cracking catalyst as used in the petroleum refining industry. Examples are powdered silica alumina, in which alumina is impregnated with dry synthetic silica gel, and various natural clays impregnated with alumina. 

The major part of these catalytic processes is carried out in fixed bed reactors. Some of the main fixed bed catalytic processes are listed in Table 11.1-1. Except for the catalytic cracking of gas oil, which is carried out in a fluidized bed to enable the continuous regeneration of the catalyst, the main solid catalyzed processes of today s chemical and petroleum refining industry appear in Table 11.1-1. However, there are also fluidized bed alternatives for phthalic anhydride— and ethylene dichloride synthesis. Furthermore, Table 11.1-1 is limited to fixed bed processes with only one fluid phase trickle bed process (e.g., encountered in the hydrodesulfurization of heavier petroleum fractions) are not included in the present discussion. Finally, important processes like ammonia oxidation for nitric acid production or hydrogen cyanide synthesis, in which the catalyst is used in the form of a few layers of gauze are also omitted from Table 11.1-1. 

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