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From: (Bruce Hamilton)
Newsgroups: sci.chem
Subject: Re: HELP NEEDED DESPERATELY!!!!!!!!!!!!!
Date: Thu, 26 Jun 1997 18:23:06 GMT

Uncle Al Schwartz <> wrote:
>Fuel - New Zealand has a major (and borderline disasterous) biomass to
>fuel program. Learn about Mobil ZSM-5 shape selective zeolite catalyst.
>Brew alcohol, convert to gasoline. Will vegetable oil work? Butter? Wool

The Mobil ZSM-5 process is *not* a biomass process. It takes valuable
natural gas, reforms it into methanol which is then converted into
methonol/dimethyl ether/water mixture. The zeolite catalysts convert
that into a hydrocarbon fraction that is fractionated to produce
high-octane gasoline feedstock that can be exported to pay for crude
oil, or used at the sole NZ refinery as blending stock.

The recent high price of methanol - driven by both the MTBE feedstck
process and the increasing demand for formaldehyde in the building
industry - has resulted in the reformers at the G-T-G ( gas to
gasoline ) plant being used to just produce methanol for sale, rather
than gasoline. As the methanol price has dropped, the gasoline output
has again increased.

The plant is owned by Methanex, who would presumably close it down
were it uneconomic. The ~ US$1 billion price tag was picked up by the
NZ government originally, but it was then sold to Methanex - with the
taxpayers picking up the significant development costs. As there are
now several alternatives to Mobil's ZSM-5 catalyst available, it's
believed the $/tonne product toll has been greatly reduced, and the
tonnes product/cycle of the catalysts have been extended as well.
Whether the plant was the best use of the natural gas is a seperate
issue, but it, and some other projects, did reduce NZ dependance on
imported foreign oil - we are about 50% self-sufficient now.

       Bruce Hamilton

From: (Bruce Hamilton)
Newsgroups: sci.chem
Subject: Re: Organic chemistry
Date: Fri, 24 Mar 2000 05:49:13 GMT

Uncle Al <> wrote:

>Pour your crap into Mobil ZSM-5 zeolite catalyst.  Get C-8 high octane
>gasoline out the other end.  Was that so !!(*&$#!! hard?  If you have
>winter and the xylenes crystallize out, engineer it.

Melting point of n-durene ( tetramethylbenzene, C10, not C8, and the
material that sheds from ZSM-5 gasoline ) is around 80C. Modern
cars are fuel injected, and durene would soon block injectors, as
well as clog up carbs at ambient temperatures around 40C-50C.
If that's winter, then I think I'll give summer a miss.

The economics of gasoline production from ZSM-5, with the requirement
to separate and/or convert the higher aromatics ( durene can be
used as a plastics feedstock ), are marginal at best, even when
considering inport substituion, as NZ did. The need to modify the
gasoline product to provide the full range octane whilst maintaining
compatibility with existing fuel systems ( 50% aromatics max ) means
that ZSM-5 streams will have better value as a refinery blending
streams than finished gasoline, and that's what happened to much of
the NZ ZSM-5 product.

The product from any of the ZSM5-type catalysts all require further
refining before continual use as gasoline, as their composition is
not suitable for modern IC engines.

      Bruce Hamilton

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