Reformulated gasoline

Hello everyone!!

Today I am going to talk about one of the several improvements gasoline has gone by, in order to adapt it to the development of fuels.

In the 90’s, several law enforcements took place in the United States, encouraging gas producers to reduce the pollution of it. Oxygenate use increased substantially with the start of the federal oxygenated fuel program (for controlling CO) in 1992. There was a great expectancy with this reformulated gasoline, which aimed to reduce gas pollution levels. It was blended in order to, reduce Volatile Organic Compounds and toxic emissions of conventional gasoline. However, its parameter values were in the same range of the normal type. So we could conclude that it was definitely not a new gasoline.

The main differences between reformulated (RFG) and conventional gasoline were the following ones

-The Reid Vapor Pressure level,wich  is a common measure of the volatility of gasoline. It was reduced in RFG only in summer, and it is the main responsible for the reduction of Volatile Orgainc Compounds in RFG.

-Reduction of benzene levels, a human carcinogen.

–Lead was definitely removed.

-In RFG Methyl Tertiary-Butyl Ether (MTBE) and ethanol (EtOH) represent the majority of oxygenate use. Oxygenates are usually employed as gasoline additives to reduce carbon monoxide that is created during the burning of the fuel.

-By the way, auto producers supported RFG because of the smaller variabaility in the quality of gas, implying a lower probability for bad gas.

-As it has been tested, these new features shouldn’t reduce vehicle’s performance.

In the following graphic, it is shown how RFG didn’t imply a revolution in the use of gas, in spite of the light improvement on the poluting agents.

Fuel Parameter Values
	Conventional gasoline				RFG
	Average	Range2			Average
RVP3	8.7-S	6.9-15.1			7.2/8.1-S
(psi)		11.5-W			11.5-W
T50 (øF)	207	141-251			202
T90 (øF)	332	286-369			316
Aromatics (vol%)	28.6	6.1-52.2			23.4
Olefins (vol%)	10.8	0.4-29.9			8.2
Benzene (vol%)	1.60	0.1-5.18			1.0 (1.3 max)
Sulfur (ppm)	338	10-1170			302 (500 max)
MTBE4 (vol%)	—	0.1-13.8			11 (7.8-15)
EtOH4 (vol%)	—	0.1-10.4			5.7 (4.3-10)

There are still several State programs to keep improving gasoline pollution levels, as this in California, which developed Phase 3 CaRFG (CaRFG3), eliminating methyl-tertiary-butyl-ether from California gasoline.

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