Naphtha-Based Chemicals

Light naphtha containing hydrocarbons in the C5-C7 range is the preferred feedstock in Europe for producing acetic acid by oxidation. Similar to the catalytic oxidation of n-butane, the oxidation of light naphtha is performed at approximately the same temperature and pressure ranges (170-200°C and =50 atmospheres) in the presence of manganese acetate catalyst. The yield of acetic acid is approximately 40 wt%. 

The product mixture contains essentially oxygenated compounds (acids, alcohols, esters, aldehydes, ketones, etc.). As many as 13 distillation columns are used to separate the complex mixture. The number of products could he reduced hy recycling most of them to extinction. 

Manganese naphthenate may he used as an oxidation catalyst. Rouchaud and Lutete have made an in-depth study of the liquid phase oxidation of n-hexane using manganese naphthenate. A yield of 83% of C1-C5 acids relative to n-hexane was reported. The highest yield of these acids was for acetic acid followed hy formic acid. The lowest yield was observed for pentanoic acid. 

In Europe naphtha is the preferred feedstock for the production of synthesis gas, which is used to synthesize methanol and ammonia (Chapter 4). Another important role for naphtha is its use as a feedstock for steam cracking units for light olefins production (Chapter 3). Heavy naphtha, on the other hand, is a major feedstock for catalytic reforming. The product reformate containing a high percentage of Ce-Cg aromatic hydrocarbons is used to make gasoline. Reformates are also extracted to separate the aromatics as intermediates for petrochemicals. 

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Most polymer products are offered for recycling in the form of mixed plastic waste (MPW). Compressed gases as solvents may offer advantages compared with liquid solvents in the necessary separations (e.g., to collect families of polymers out of MPW) because such solvents are easy to recover and, furthermore, they make it possible to use pressure as an additional separation parameter or to remove the organic additives of the polymers. Finally, MPW may be added as a polymer solution in a compressed gas to a feed of a Naphtha cracker, and thus be recycled to base chemicals. 

National Organic Chemical Ind. Ltd (NOCIL) was established in the early 1960s with a series of collaborative agreements with Shell and UOP and was the first company to set up a naphtha based cracker in... 

Example 5 (Batch pipeline sequencing). Suppose a one-to-one serial pipeline that connects two chemical sites. The provider site prodtices the raw and intermediate materials for the consumer site. Suppose that the consumer site produces Styrene-based chemicals such as Polystyrene and Styrene-Butadiene rubber. Raw materials for Styrene production are Benzene and Ethylene. Among others, a steam cracker provides Ethylene and Pygas, which is subsequently refined to Benzene. It is assumed that the capacities of these plants are unbalanced such that the deficit of Pygas and Benzene has to be imported. Additionally, the cracker feed, Naphtha, has to be imported. 

For all industrialized countries the chemical industry is an important part of the economy. However, compared to the oil, gas, and coal industries - which are equally reliant on chemical technology - the chemical industry is relatively small. In 2011, six of the ten (and ten of the 20) most important companies by revenue were primarily oil and gas companies, and the biggest chemical company (BASF) was ranked only 62 (Table 1.2.1). Thus the chemical industry, which produces chemicals ranging from base chemicals to fine chemicals mainly from crude oil derivatives, such as naphtha and liquefied petroleum gases (LPG), is still has a free ride in terms of energy consumption, which is still mainly driven by crude oil. 

This 5 billion (USD) petrochemical plant will have an annual capacity of 1.5 million metric tons (3.3 billion pounds) of ethylene and will manufacture 1.0 million metric tons (2.2 billion pounds) of polyethylene. Note that ethylene capacity in a world-class complex usually exceeds the volume of polyethylene production. This excess ethylene capacity is either used to manufacture other ethylene-based chemicals at the same complex or is sold as a commodity chemical when access to a distribution pipeline is available. This plant will utilize ethane as the feedstock for ethylene, which has a cost advantage over ethylene plants that use oil-derived naphtha as feedstock. 

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). 

Superficially the Oryx GTL refinery design has much in common with the SMDS process, but there are important differences. There is no separate hydrotreater, which limits production of chemicals, such as waxes. The hydrocracker employs the Chevron Isocracking technology, which is based on a sulfided supported base-metal catalyst that was designed for crude oil conversion. The operating conditions of the hydrocracker are also more severe (>350°C, 7 MPa) than those required by the SMDS process (300-350°C, 3-5 MPa). Only intermediate products are produced (Table 18.13),5 with the naphtha slated as cracker feed and the distillate as blending component for diesel fuel. 

In addition, a method of petroleum classification based on other properties as well as the density of selective fractions has been developed. The method consists of a preliminary examination of the aromatic content of the fraction boiling up to 145°C (295°F), as well as that of the asphaltene content, followed by a more detailed examination of the chemical composition of the naphtha (bp < 200°C < 390°F). For this examination a graph is nsed that is a composite of cnrves expressing the relation among the percentage distillate from the naphtha. 

It is reasonable to assume that prior to the exclusive use of chemicals derived from feedstocks other than crude oil, chemicals based on crude oil and chemicals based on alternate feedstocks will supplement each other. This situation has already arisen as is exemplified in the use of coal derived CO/H2 to hydroformylate olefins originating from mineral oil. For instance, in West-Germany Hoechst converts coal into CO/H2 which is used to prepare alcohols from naphtha derived olefins. Table IV summarizes a number of additional reactions in which this point is especially emphasized. 

A comparison has been made of Platforming and of thermal reforming from the standpoint of yield-octane number relationships, product properties, hydrocarbon types, and with respect to the nature of chemical reactions responsible for improvement of octane number. Comparison is based on studies of thermal reforming in a commercial operation at a Pennsylvania refinery and in a pilot plant on a midcontinent naphtha and in pilot plants and laboratory Platforming on the same stocks. 

The nature of the specific additional processing that will be installed will be specific to each individual refinery s base situation, but in general the effect will be to increase the value of several of the by-products associated with ethylene production. These include propylene, butylene, and the aromatics in the pyrolysis naphtha. The prices of the two olefins will tend to rise as additional alkylation units are installed to boost gasoline octanes, thus making these chemicals more valuable to the... 

Ever since Nehemiah demonstrated, albeit with divine assistance, that naphtha would burn,1 man has increasingly relied on oil and oil based products for fuel as well as for feedstocks for the chemical industry. However, it was not until the invention of the internal combustion engine in the latter part of the 19th century that total exploitation of this resource became a reality. 

The FTS converts synthesis gas into mostly liquid hydrocarbons [12-15]. Depending on the origin of the synthesis gas, the overall process from carbon feedstock to liquid product is called gas-to-liquids (GTL), coal to liquids (CTL), or biomass to liquids (BTL). The product spectrum, however, is broader than liquid hydrocarbons alone and can include methane and alkanes, C H2 +2 (with n from 1 — 100), alkenes or olefins (C H2 n > 2), and to a lesser extent, oxygenated products such as alcohols. Hence the FTS offers the opportunity to convert gas, coal, or biomass-derived syngas into transportation fuels, such as gasoline, jet fuel, and diesel oil, and chemicals, such as olefins, naphtha, and waxes. The reactions need a catalyst, which in commercial applications is either based on cobalt or iron. 

Oswal Agro Mills Ltd. is an agricultural company with several fertilizer plants with a small (naphtha) cracker producing 22,000 t/y ethylene near Mumbai (Bombay). Chemplast Sanmar Ltd. (CSL) is a small company focusing on the production of chloro-chemicals. Based in Tamil Nadu, the company has a small ethylene plant which uses ethanol as a feedstock. 

The petrochemical complexes in Malaysia are export driven. The competitive advantages lie in low priced gas feedstock and large integrated plants based on naphtha. The resulting complexes are able to deliver chemical intermediates throughout the Far East. 

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