Gasoline specific consumption

West European production capacity for MTBE is estimated at 3.61m tonne, unchanged since 1998. In 1999, west European production, at around 3m tonne, represented an 83% operating rate. Consumption was considerably lower at 2.2m tonne. Europe s new gasoline specification, which came into force in January 2000, has lifted consumption to an estimated 2.7m tonne in 2000. MTBE is used to boost octane in gasoline and to promote cleaner burning and reduce harmful vehicle emissions. Demand to meet 2000 gasoline specifications in Europe boosted prices from 250 US dollars/tonne mid-1999 to touch 600 US dollars/tonne fob Rotterdam briefly in June 2000. There is increasing likelihood that the California ban on the use of MTBE, due to come into effect end 2002, will lead to further bans in the US marketplace. 

In practice, the user prefers the densest possible motor fuel that is compatible with the specifications, for it gives him the best volume NHV and highest fuel economy. It is estimated that an increase in density of 4 to 5% brings a reduction in consumption of 3 to 5%. Finally for the refiner, a margin of 50 thousandths accorded for the density of each type of gasoline, makes an acceptable compromise, while a tightening of the specification would be too constraining. 

Sweetening of the FCC gasoline is usually sufficient to meet its sulfur specifications. However, in areas where reformulated gasoline is marketed, sulfur specifications in the gasoline may require more treatment. The mercaptans in the LPG need to be extracted to protect the downstream processes, such as alkylation. Sulfur increases acid consumption and produces undesirable by-products. 

A second compromise between the other specifications which will be set for fuels in 2005 and the increase in self-consumption has also to be found. Some of these specifications are effectively interdependent and this interdependence must be taken into account when selecting them. For instance, in the future why would it be necessary to keep the aromatics content below 35% in gasoline if the almost complete elimination of sulphur enables total elimination of harmful hydrocarbons discharged in exhaust gas (50) A similar question can be asked regarding the lowering of the T95 in diesel fuel which aims at limiting the formations of polyaromatics and soot in exhaust gas, when eventually diesel vehicles will be fitted with particle filters (50). 

Determine the mass flow rate of fuel fi-om the gasoline tank to the cars fuel injection system. Assume that the gasoline consumption of the car is 20 mpg when the car is moving at 60 mph. Use the specific gravity value of 0.72 for the gasoline. 

As briefly menfioned in section 10.2.1, polyamides are selected for their performance and thus specific properties with only a minor price pressure. In recent years, the automotive market has evolved to become the single largest application field for moulded polyamides. They are selected for their excellent resistance to chemicals (such as gasoline and other petroleum products) and the environment (such as water and light) plus their relatively high temperature stability. Much of the growth mentioned in section 10.1.2 is derived directly from this market to the point that the total polyamide consumption is stipulated and almost dependent on the success of new car and tmck production. 

Despite the high tonnages of petrochemicals, the chemical industry as a whole consumes rather less than 10% of available petroleum and natural gas hydrocarbons as feedstocks, with possibly a further 4-5% as fuel. For comparison, the current consumption of gasoline alone in Western Europe exceeds 120 Mt per annum, while the U.S. figure is over 300 Mt per annum. Hence, prices of individual hydrocarbon feedstocks are largely determined by other forces the most economic feedstock/route combination has frequently changed with time, and may differ in different parts of the world. Furthermore, while a specific route may be preferred for new plants, older plants for which the capital is largely written off may well remain economically viable. Finally, special situations may prompt individual solutions. For example, Rhone-Poulenc in France derive the carbon monoxide for a very modern acetic acid plant, based on Monsanto s methanol carbonylation process, from the partial... 

In the past, there was little incentive to process C5 olefins in the alkylation unit because they were normally included in the gasoline pool due to their acceptable octane rating and they cause higher acid consumption in the alkylation process. However, the recent Clean Air Act Amendment specification on RVP and potential evaporative emissions could force U.S. refineries to back out C5 olefins from the gasoline pool and upgrade them via alkylation or etherification. Although acid consumption will increase, both HF and sulfiiric acid processes can alkylate the C5 olefins, producing similar octanes as shown in Table 19. Table 20 compares the properties of the C5 olefins before and after alkylation (Lew et al, 1991). 

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