Gasoline, production

Other major components in gasoline come from catalytic reforming, alkylation and the addition of an oxygenated octane booster, methyl tertiary-butyl ether (MTB E). 

We will briefly discuss these processes, which together are responsible for roughly 75% of the principal components in gasoline. 

Jet fuels with octane numbers above 100 are tested against standards containing octane boosters. 

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One can react methanol with the tertiary olefins having five c irbon atoms (isoamylenes). This process increases the octane number of FCC olefinic C5 fractions, in order to reduce the concentration of olefins and to increase gasoline production. 

This process thus enables gasoline production to be increased if the propylene can not be used for petrochemical manufacture. It recovers ethylene economically from fuel-gas. 

Hydrocracking is a major process for the production of diesel motor fuel catalytic cracking is its counterpart for the gasoline production. 

Furthermore, the major problem of reducing aromatics is focused around gasoline production. Catalytic reforming could decrease in capacity and severity. Catalytic cracking will have to be oriented towards light olefins production. Etherification, alkylation and oligomerization units will undergo capacity increases. 

IFP (1989), Gasoline production in the next decade new trends . Booklet from Direction Industrielle de I lnstitut Frangais du Petrole, symposium Venezia. 

Properties. Table 4 contains typical gasoline quaUty data from the New Zealand plant (67). MTG gasoline typically contains 60 vol % saturates, ie, paraffins and naphthenes 10 vol % olefins and 30 vol % aromatics. Sulfur and nitrogen levels in the gasoline are virtually lul. The MTG process produces ca 3—7 wt % durene [95-93-2] (1,2,4,5-tetra-methylbenzene) but the level is reduced to ca 2 wt % in the finished gasoline product by hydrodealkylation of the durene in a separate catalytic reactor. 

Fig. 10. Simplified flow diagram depicting the ARCO gas-to-gasoline process for a conceptual gasoline production plant (72).

Methyl -Butyl Ether. MTBE is used as an oxygen additive foi gasoline. Production of MTBE in tiie United States has increased due to the... 

Refinery Production. Refinery propylene is formed as a by-product of fluid catalytic cracking of gas oils and, to a far lesser extent, of thermal processes, eg, coking. The total amount of propylene produced depends on the mix of these processes and the specific refinery product slate. For example, in the United States, refiners have maximized gasoline production. This results in a higher level of propylene production than in Europe, where proportionally more heating oil is produced. 

The reduction ia tetraethyl lead for gasoline production is expected to iacrease the demand for petroleum alkylate both ia the U.S. and abroad. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used. However, concerns over the safety or potential regulation of hydrofluoric acid seem likely to convince more refiners to use the sulfuric acid process for future alkylate capacity. 

Although 600 m of water is used to make a metric ton of fertilizer, 150—240 m to make a tonne of steel, 480 m to make a tonne of gasoline, and 1000 m to make a tonne of acetate fiber, Htde if any is required chemically in any of these processes. Recycling can reduce industrial requirements by a factor of 10—50. Much of this water, particularly that for cooling, and often that for washing, can be saline. Some petroleum refiners have used salt water to remove heat (water s principal role in gasoline production), and some have actually produced table salt by evaporation in cooling towers. 

The purity of the cerium-containing materials depends on the appHcation as indicated in Table 3, and purity can mean not only percentage of cerium content but also absence of unwanted components. For some uses, eg, gasoline production catalysts, the lanthanides are often used in the natural-ratio without separation and source Hterature for these appHcations often does not explicitly mention cerium. Conversely, particulady in ferrous metallurgy, cerium is often assumed to be synonymous with rare-earth or lanthanide and these terms are used somewhat interchangeably. 

The San Juan plant can process up to 500 MMcfd of gas, and extract 40,000 bbl of EPBC liquids. EPBC liquids include ethane (E), propane (P), butanes (B), and condensate (natural gasoline) products... 

Oxidation or "sweetening" is used on gasoline and distillate fractions. A common oxidation process is also a Merox process that uses a solid catalyst bed. Air and a minimum amount of alkaline caustic ("mini-alky" operation) is injected into the hydrocarbon stream. As the hydrocarbon passes through the Merox catalyst bed, sulfur mercaptans are oxidized to disulfide. In the sweetening Merox process, the caustic is not regenerated. The disulfide can remain with the gasoline product, since it does not possess the objectionable odor properties of mercaptans hence, the product has been sweetened. 

The fat oil is fed to a splitter or stripping tower, where the absorbed tight constituents are separated from the oil by distillation. Usually the lean oil is the same material as the heavier part of the absorber feed, so that the bottoms from the stripper are split into lean oil, which is recycled to the absorber, and a stabilized gasoline product, which is passed on to subsequent processing operations. 

The temperature at the base of the de-butanizer determines the vapor pressure of the gasoline product. If its vapor pressure is too high, the temperature must be increased or the tower pressure decreased to drive more butanes-minus out of the bottoms liquids. 

TEL was not the only way to increase octane number. Those few companies who did not wish to do business with Jersey Standard, sought other means to produce a viable premium gasoline. TEL represented the most serious threat to the traditional gasoline product. It was cheap, vei y effective, and only 0.1 percent of TEL was required to increase the octane number 10 to 15 points. In contrast, between 50 to 100 times this concentration was required of alternative octane enhancers to achieve the same effect. 

The main use of naphtha in the petroleum industry is in gasoline production. Light naphtha is normally blended with reformed gasoline (from catalytic reforming units) to increase its volatility and to reduce the aromatic content of the product gasoline. 

In the moving bed processes, the preheated feed meets the hot catalyst, which is in the form of beads that descend by gravity to the regeneration zone. As in fluidized bed cracking, conversion of aromatics is low, and a mixture of saturated and unsaturated light hydrocarbon gases is produced. The gasoline product is also rich in aromatics and branched paraffins. 

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