Octane number of petrol

Components 2, 4, 7, 8 and 9 have the lowest effects on the octane number of petrol. 

The octane number of petrol is a measure of its quality - an octane number of 0, for a particular petrol, means that it bums as well as pure heptane. If the octane number is 100, then the fuel is equivalent to pure 2,2,4-trimethylpentane. Many petrols have an octane number of 70 they bum as would a mixture of 70% 2,2,4-trimethylpentane and 30% heptane. 

The octane number of petrol is a measure of its quality, and is based on the ignition properties of an isomer of octane, CgHjg. The branched alkane,... 

Nine design points in accord with a simplex lattice design for a second-order model was done in researching for the octane number of a three-component mixture of petrol. The outcomes are given in Table 3.23. 

PC. Anderson, J. M. Sharkey and R. P. Walsh, Calculation of the research octane number of motor gasoline quality control, J. Inst. Petrol, 58, 83-94 (1972). 

The Research Octane Number or RON characterizes the resistance of a fuel to engine knock. This phenomenon, which occurs as a characteristic metallic sound, brings about deteriorations in the cylinder walls, in the valves and in the piston. The RON of the petrols sold in Europe have standard values of 95 or of 98. The use of a petrol of RON lower than those advised by the car manufacturer leads to the destruction of the engine. The Research Octane Number of a given petrol is measured using specific engines (of the CFR type) according to standardized processes. 

Apart from FT synthesis for naphtha, the MtSynfuels process has the advantage of sufficiently high octane numbers (RON 92) of the naphtha fraction. Therefore, this naphtha can be used directly as a fuel (gasoline) for petrol engines without further upgrading (Liebner et al., 2004). 

The response surface of the petrol octane number has small nonlinearity. 

Inui, T., Okazumi, F., Tarumoto, J., Yamase, O., Matsuda, H., Nagata, H., Daito, N. and Miyamoto, J. Highly selective synthesis of high octane-number gasoline from fight olefins on iron-silicates. Jpn. Petrol. Inst., 1987, 30, 249-256. 

For the production of styrene/ethylbenzene, cumene/phenol, and cyclohexane as a solvent as an additive in petrol to increase the octane number 3511,3521,353, 354,... 

Many pyrolysis processes produce a petrol fraction with a favourable octane number, but strong gum-forming tendency due to the presence of mainly branched olefins. 

Branched hydrocarbons are preferred to linear hydrocarbons as ingredients in petrol because they enhance the fuel octane number. By catalytic isomerisation linear hydrocarbons are converted into mono and di branched hydrocarbons, and it becomes necessaiy to separate the mixture. A variety of zeolites may be used for this purpose, either on the basis of sorption thermodynamics or on the basis of sorption kinetics. Such data are relevant to the development of sorption based separation methods, but also they provide key information regarding the catalytic isomerisation over zeolites themselves. 

Exposure to airborne lead from motor vehicles using leaded petrol has been the subject of a great deal of scientific debate. Old vehicles with poor emission control are allowed to travel freely on the Indian roads. Currently, there is no effort towards providing lead-free petrol in India, whereas in all major cities of the industrialized nations strict emission controls are enforced. The use of cleaner fuels [10] has led to declining emissions in recent years. In India, the lead content in petrol has increased with a rise in the octane number from 83 to 87 since 1983. 

In these particles, lead is present, which is added to petrol in the form of tetraalkyllead (most frequently tetraethyllead) as an admixture for increasing the octane number ( ethylized fuel ). 

Atmospheric lead emissions in Nigeria have been estimated to be 2800 metric tonnes per year with most (90%) derived from automobile tail pipe (Nriagu et al, 1997). Lead in the form of tetra-ethyl lead Pb(C2H5)4 is the most common additive to petrol to raise its octane number. Upon combustion in the petrol engine, the organic lead is oxidized to lead oxide according to the following reaction ... 

Lead tetraethyl is used in fuel for internal-combustion engines (along with 1,2-dibromoethane) to increase the octane number and reduce preignition. However, its use in petrol results in the emission of hazardous lead compounds into the atmosphere. Pressure from environmental groups has encouraged a reduction in the use of lead(lV) tetraethyl and an increasing use of lead-free petroL See knocking. 

The previous sections have given a very brief overview of the PPDS-2 calculation program. The examples given in the Appendix illustrate typical outputs obtained from the system. Example 1 shows the calculated pure component properties of tert-amyl methyl ether, which is commonly used as a lead-free additive to petrol to increase its octane number. Example 2 gives the results of a phase envelope calculation, illustrated in Figure 17.7, for a liquified natural gas mixture, typical of those which are pumped ashore from the North Sea. It contains a large amount of dissolved carbon dioxide. These examples have only scratched the surface of the available calculations which, due to the lack of space, are not possible to review here. 

Chlorine is one of the most common chemicals in the world. It is produced in huge quantities. Hydrogen is a by-product of catalytic reforming of petrol, made to improve the octane number. It is also a by-product of steam cracking of hydrocarbons for the production of ethylene. This hydrogen is used in other refinery operations. Smaller volumes of hydrogen are by-products in coke ovens and usually are kept for internal use. All by-product hydrogen requires some purification steps before use. 

For early polymerization units, the catalyst was phosphoric acid on a quartz or kieselguhr support. Many of these units were shut down when the demand for gasoline with increased octane numbers prompted the diversion of the olefin feeds to alkylation units that gave higher octane number products. Yet some refinery balances have more propylene than alkylation can handle, so a newer version of polymerization was introduced.It is the Dimersol process of the Institut Frangais du Petrole, for which the flow diagram is shown in Fig. 15.18. 

Although many different forecasts can be made, it is certain that oil will continue to become scarcer, with the result that its price will increase drastically and alternative fuels will become more important. Legislation in a number of countries has reduced the tetraethyl lead content of petrol. Aromatics are therefore being added to compensate for the reductions in octane numbers which would otherwise result. Low-lead petrol in the Federal Republic of Germany has an aromatics content of 40-45 %, whereas the corresponding figure in the United States is 33-36 %. 

There is a good correlation between autoignition temperatures and octane or cetane numbers in motor fuels. Thus, toluene and diisopropyl ether make attractive additives for petrol while the low autoignition temperature of glycol ethers, diethyl ethers and some normal paraffins show them to have high cetane numbers and to be useful as cold start improvers for diesel compression/ignition engines. 

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