I heard that ethanol, as an alternative for MTBE, has some problems. Does anyone know its concerns? What are the other alternatives?
Ethanol emits more harmful smog-forming emissions during the summertime than MTBE due to its high tendency to evaporate. Because ethanol is used in lower volumes, it provides less reduction in toxic air emissions than MTBE. Ethanol also can contribute to increased NOx emissions.
Alkylates are promising alternative to MTBE. Although the other fuel additive such as ethyl tert-butyl ether ETBE and tert-amyl methyl ether TAME are also alternatives to MTBE.
Ethanol is popularly used as alternative fuel substitued for MTBE in some countries like in the U.S.A. and Brasil as well in China. ETBE is used in European countries. Additionally, methanol is also used as alternative for MTBE such as in several European countries and in the part regions of China.
ETBE and TAME have many health concerns as for MTBE. So we can not count on them for future. Ethanol has also some problems when it burns in motor.
Is there any other alternatives?
you need to be clear - MTBE is an oxygen bearing compound used for boosting OCTANE number.
other non oxygenate compounds that increase octane number are Aromatics, Alkylates and IsoParaffins.
Most of the countries have regulations with respect to amount of OXYGENATES and Aromatics.
so for the purpose of Octane Number boosting if MTBE use is limited by the limit on oxygenates content, then you can consider Alkylates, Isoparaffins, and Aromatics.
if you are with in oxygenates limit but do not have enough oxugenates, then TAME , ETBE could be considered.
ON PURPOSE ISOPARAFFINS CAN BE PRODUCED THROUGH COMMERCIALLY AVAILABLE PROCESSES.
THUS ALTERNATIVES TO OXYGENATES CAN BE EXPLORED BASED ON THE CONTEXT WHICH PROMPTED THIS QUESTION.
Raju really has said much on the chemistry and environmental consideration and implication of Octane enhancement. All oxygenated enhancers are lower ozone layer depleting agents because they form -CHO- although they are more octane efficient than the isoparaffin and aromatic & alkylates. From low Ozone depletion efficiency point of view isoparaffin, and C2/C3 alkylates should be preferred, but this is also subject to the unit cost of the fuel and engine specification. Choice should be drawn from economic, environmental and engine specification demands.
MTBE is oxygenated compounds which used as additives on gasoline for enhancing the properties or physicochemical characteristics of it. Other alternatives for MTBE is ethanol, Isopropanol alcohol(IPA), Methanol, Ethyl Tertiary Butyl Ether(ETBE), TAME and DIPE. oxygenated compounds enhance the octane number.
Dimerized isobutene, An alternative to MTBE
Although the other fuel additive ethers such as ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are alternatives to MTBE, they are not likely to be favored by refineries, lest they “go the MTBE way”. MTBE has been a major consumer of isobutene from the C4 hydrocarbon stock, and its phaseout will cause a major decline in the downstream consumption of isobutene from fluid catalytic cracking (FCC) and steam cracking product streams. Therefore, an additive that comes from isobutene is likely to have an edge over the non-C4 candidates such as TAME, ethanol, and isomerates (highly branched alkanes derived from pentanes and hexanes).
Alkylates are branched paraffins with carbon numbers in the range C8–C12 (isooctane is one example). Alkylates from C4 streams possess the high octane numbers required for gasoline additives and are expected to find a prominent place in the gasoline additives market. The average octane number for alkylates is in the range of 93–96. (This number is obtained by taking an arithmetic average of the research octane number and the motor octane number.)
Although alkylates have the potential to match most of MTBE’s properties, their boiling range (70–150 °C) is substantially higher than the boiling point of MTBE (52 °C). An appropriate blend of C5–C6 isomerates with alkylates would match the volatility of gasoline and be a perfect replacement for MTBE. However, the mandatory minimum 2% oxygen requirement in gasoline, as stipulated by the 1990 Clean Air Act (3), would have to be relaxed for this blend to be used in the United States.
http://pubs.acs.org/subscribe/archive/ci/31/i03/html/03mahajani.html
Dear Dr. Hamidreza Hajfarajollah,
I have a question that you may have good enough information for me.
As it is not relevant to the current discussion, I do prefer to ask it via e-mail.
May you please send me your contact e-mail?
My email address is: [email protected]
Ahmad
In the production process of the octane boosters (MTBE/ETBE/TAME) there is the participation of an strong acid ion exchanger , has anyone done any research with this process and the use of Lewatit products? A customer is asking for recent references for documentation process. Thanks in advance
- Badges
- Science topic