Naphtha chemicals from

Figure 2.2.1 The production of functionalized chemicals from naphtha or from biomass [6],...

Other chemicals operations are in Sarawak. Offshore gas feeds a large methanol plant (660 kt/y) on Labuan Island and an ammonia plant at Bintulu. Also at Bintulu is the large Shell Gas to Liquids plant, which produces high valued linear-paraffins and wax as by-products. The naphtha fraction from the GTL plant is used as petrochemical naphtha. 

As shown, it is possible to recover directly high amounts of olefins similar to that of a naphtha crackers from polyolefin wastes. For selling, the olefins have to be cleaned up in distillation plants. To avoid problems with HCl from unexpected PVC fractions, it is safer to produce from polyolefins a waxy material which can be analyzed and, if free from HCl and chloroorganic compounds, mixed with naphtha and used as cracker feed. This was the concept of BP Chemicals. The test runs were made in our Hamburg laboratory plant (LWS3) [15]. Detailed material balances for experiments are provided in Table 17.7... 

Benzene [71-43-2] toluene [108-88-3] xylene [1330-20-7] and solvent naphtha are separated from the light oil. Benzene (qv), toluene (qv), and xylene are useful as solvents and chemical intermediates (see Xylenes and ethylbenzene). The cmde light oil is approximately 60—70% ben2ene, 12—16% toluene, 4—8% xylenes, 9—16% other hydrocarbons, and about 1% sulfur compounds (5) (see BTX processing). 

Benzene, toluene, and xylene are made mosdy from catalytic reforming of naphthas with units similar to those already discussed. As a gross mixture, these aromatics are the backbone of gasoline blending for high octane numbers. However, there are many chemicals derived from these same aromatics thus many aromatic petrochemicals have their beginning by selective extraction from naphtha or gas—oil reformate. Benzene and cyclohexane are responsible for products such as nylon and polyester fibers, polystyrene, epoxy resins (qv), phenolic resins (qv), and polyurethanes (see Fibers Styrene plastics Urethane POLYiffiRs). 

Chemical and Other Specialty Manufacture A wide variety of products may be derived from petroleum feed stocks, including such diverse materials as alcohols, butyl rubber, sulfur, additives, and resins. Other specialties such as solvent naphthas, white oils, Isopars, Varsol, may also be produced. As indicated previously the respective chemical affiliate usually has responsibility for products broadly classified as petrochemicals. 

Rerunning is a second distillation step applied to distillate stocks in order to remove undesirable higher boiling materials from the product. These materials may be present because of poor fractionation in the primary distillation step more frequently they are heavy polymers formed in treating operations. Rerunning may be combined with solvent removal, as in the case of heavy lube distillates which are diluted with naphtha to lower their viscosity before being chemically treated. 

Synthesis gas is an important intermediate. The mixture of carbon monoxide and hydrogen is used for producing methanol. It is also used to synthesize a wide variety of hydrocarbons ranging from gases to naphtha to gas oil using Fischer Tropsch technology. This process may offer an alternative future route for obtaining olefins and chemicals. The hydroformylation reaction (Oxo synthesis) is based on the reaction of synthesis gas with olefins for the production of Oxo aldehydes and alcohols (Chapters 5, 7, and 8). 

Another nonsynthetic source for cyclohexane is natural gasoline and petroleum naphtha. However, only a small amount is obtained from this source. The 1994 U.S. production of cyclohexane was approximately 2.1 billion pounds (the 45th highest chemical volume). 

Polyethylene is the most extensively used thermoplastic. The ever-increasing demand for polyethylene is partly due to the availability of the monomer from abundant raw materials (associated gas, LPG, naphtha). Other factors are its relatively low cost, ease of processing the polymer, resistance to chemicals, and its flexibility. World production of all polyethylene grades, approximately 100 billion pounds in 1997, is predicted... 

When crude oil is refined, some of the processes yield additional gaseous products. The C3 and C4 constituents differ from those released from crude oil or from NGLs, which are saturated hydrocarbons. Refinery gases are high in unsaturates, e.g. propane (propylene) and butane (butylenes). These unsaturated hydrocarbons are a valuable source of chemical process intermediates and enjoy a large market alongside naphtha. 

Oxygenate refining was limited to chemicals recovery from the Fischer-Tropsch aqueous product and acidic isomerization of the C5-C6 naphtha. The naphtha and distillate range oxygenates were removed by hydrodeoxygenation (HDO) in hydrotreaters, before further refining. 

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