Switching to unleaded gasoline

Switching to unleaded gasoline

By Kardono

JAKARTA (JP): The use of leaded petroleum is gradually being
phased out worldwide, because of increasing recognition of health
risks of lead exposure and the introduction of catalytic
converters, which require unleaded petroleum. However, as each
country considers the issues of leaded petroleum, the same
questions are revisited concerning health risks, technical
feasibility and costs.

Unleaded petroleum, that grand scheme to help us all breathe
easier, is getting more attention. Some countries have replaced
leaded petroleum with the unleaded type whereas others, including
Indonesia, have still kept lead in petroleum as a main octane
booster.

Indonesia planned to phase out lead in petroleum in 1993 but
the plan was stalled due to the economic crisis. Reports say
unleaded petroleum may be implemented as soon as July 2001 in
Jakarta, to be followed by other cities.

In general, the transition to unleaded petroleum will require
refinery improvements and perhaps the use of other additives,
such as methyl tertiary-butyl ether (MTBE).

The basic refinery options to produce unleaded petroleum
include catalytic reforming, which results in higher octane
aromatics (such as benzene, xylene, and toluene) and
isoparaffins; and isomerization, which transforms normal
paraffins into higher-octane isoparaffins.

Whereas, MTBE, one of the petroleum additives, is a chemical
compound manufactured by the chemical reaction of methanol and
isobutylene -- a liquefied petroleum gas. It is among a group of
chemicals commonly known as "oxygenates" because they raise the
oxygen content of petroleum.

Most refiners have chosen MTBE over other oxygenates as a lead
substitute primarily for its blending characteristics and for
economic reasons.

MTBE has been used in petroleum to replace lead as an octane
enhancing material, which helps prevent the engine from
"knocking". Oxygen helps petroleum burn more completely and
therefore reduce harmful tailpipe emissions from motor vehicles.
In one respect, the oxygen dilutes or displaces petroleum
components such as aromatics (e.g., benzene) and sulfur. In
another, oxygen optimizes the oxidation during combustion.

The Balongan refinery of the state oil firm Pertamina has
chosen catalytic reforming in the production of its unleaded
petroleum. The government's choice of the next type of unleaded
petroleum is still unclear. Thailand for example, is making the
transition from leaded petroleum with 0.45 gram per liter to
unleaded petroleum using both refinery improvements and MTBE.

In Malaysia, the production of unleaded petroleum is similar
to that in Thailand. In the European Union, unleaded petroleum is
mostly carried out by blending oxygenate additive of MTBE into
petroleum.

In the United States, the unleaded petroleum program has been
implemented through the Clean Air Act Amendments of 1990 (CAAA).
The Act contained two primary requirements for cleaner petroleum.
The first, known as the oxygenated fuels program, began during
the winter of 1992-1993 and required all petroleum sold in 39
carbon monoxide (CO) nonattainment areas to contain 2.7 percent
oxygen. Nonattainment areas in the United States are areas which
have failed to comply with ambient air quality standards, due to
their very high levels of emissions.

The higher oxygen content helps to reduce CO emissions,
especially during the winter months when most CO violations
occur. The other fuel program, known as the reformulated gasoline
(RFG) program which requires cleaner-burning reformulated
petroleum, has been sold in the nine worst ozone nonattainment
areas since Jan. 1, 1995.

About 40 other cities have voluntarily adopted the RFG
program. Among requirements of the program are that the
reformulated gasoline must have an oxygen content weight of 2
percent, a maximum benzene content of 1 percent, and no heavy
metals.

RFG is also subject to a performance standard; among others it
should lead to a 15 percent reduction of volatile organic carbon
and toxic air emissions from baseline levels between 1995 and
2000.

Ambient monitoring data from the first year of the RFG program
in 1995 showed strong signs that RFG was working. For example,
detection of benzene (one of the air toxins controlled by RFG,
and a known human carcinogen) declined dramatically, with a
median reduction of 38 percent from the previous year.

Actually, neither the Clean Air Act nor the Environmental
Protection Agency (EPA) requires the use of MTBE in reformulated
gasoline. The 1990 Clean Air Act Amendment did not specify which
oxygenate to use. However, both MTBE and ethanol are, in fact,
used successfully in the current RFG program with the MTBE more
dominantly used by some 80 percent fuel providers.

Despite air quality improvement aspects of oxygenates in RFG,
there is growing concern about contamination of drinking water by
MTBE in some areas. EPA is also concerned about detected MTBE in
drinking water, as well as ground and surface waters.

As of June 1999, MTBE was detected in 3.7 percent of samples
of water from California's drinking water systems. It was
reported that about 3 percent of ground water wells in RFG
program areas were detected to contain MTBE at or above five
parts per billion. This was primarily a result of leaking
underground fuel storage tanks, and possibly from spills from
distribution facilities.

Some users do not accept the RFG program based on complaints
of MTBE contributing to negative health effects, increased fuel
prices, and lower engine performance. Reported health effects
include headaches, dizziness, nausea, sore eyes and throats, and
respiratory irritation.

Research about MTBE health effects has been inconclusive,
however, most studies have failed to find acute health effects.
RFG is expected to benefit health by helping areas achieve
cleaner air. On average, RFG has decreased the use of fuel by two
miles to three miles per gallon because oxygenates have lower
energy content than petroleum. There are reports of much more
savings of fuel for some vehicles. There are also reports that
small engines do not perform well using RFG.

There is now a growing debate concerning environmental and
health effects of MTBE. No doubt unleaded petrol using MTBE
additive has resulted in cleaner air quality. However some
researchers have revealed indications of MTBE contaminating
water, and community members have also reported on its suspected
effects on health.

Thus, the change from leaded to MTBE-unleaded petrol may lead
to a shift from the issue of improving air quality to water
quality problems. The states of California and Maine have ordered
the phasing out of MTBE in their respective RFG programs. Several
congressional hearings have been held to seek a solution.

The lesson for us here is how to find the best available
technology in producing unleaded petrol. The decision is urgent
given growing concern about air quality due to leaded gasoline.
There is no such thing as a clean technology for eternity because
the clean technology that we might choose today may be no longer
clean in the future.

Thus decisions on such an important matter must include all
related parties -- the government and the people, based on
comprehensive assessment.

The writer, who holds a Phd. in air pollution, works for the
Agency for the Assessment and Application of Technology (BPPT).