Mobil man suggests N.Z. use methanol in own fuel

Press, 18 March 1983, Page 29

Mobil man suggests N.Z. use methanol in own fuel

NZPA staff correspondent Paulsboro, New Jersey

As world methanol prices are low, it might make sense to feed the methanol from the stand-alone plant at Waitara into the gas-to-gasoline plant at Motunui instead of selling it abroad, a Mobil Oil Company executive has suggested. Oil and gas industry analysts predict low methanol prices for some years as new, efficient plants come on stream in such countries as Saudi Arabia, Canada and the United States and compete in a crowded world market.

The Minister of Energy, Mr Birch, said in February that the Waitara plant would probably have to ride out depressed prices during its initial production phase. The Motunui plant will convert Maui natural gas to methanol, and that methanol to gasoline, but the production rate of 13,000 to 14,000 barrels a day — about 570,000 tonnes a year — will provide only a third of New Zealand’s needs.

Injection of the 1200 tonnes a day of methanol that the Waitara plant will produce would provide something like another 150,000 tonnes of petrol a year.

In Calgary last year, when the Prime Minister, Mr Muldoon, visited methanol plants after attending an International Monetary Fund meeting in Toronto, industry executives said the only thing that would lift methanol prices significantly would be for a big market such as the United States to decide to blend methanol into most of its petrol. This is being done only on a very small scale, with little apparent prospect of blends emerging as a major fuel. Dr Wooyoung Lee, manager of synthetic fuels development at Mobil’s research, and development Complex at Paulsboro, suggested diverting the Waitara methanol to Motunui, during a tour by this correspondent of the fixed-bed plant set up as a pilot for the Motunui project. Dr Lee cautioned against Sl-methianol blends as to cause too many

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technical and distribution problems. Mobil was now doing large-scale tests on a second-generation methanol-to-gasoline process in West Germany, Dr Lee said, and a number of countries — not all of them small — were interested in following New Zealand’s lead.

“Some of the inquiries are quite serious,” he said. “They are coming in all the time.”

Dr Lee and three colleagues said in. a paper presented in New Orleans three years ago that once the Motunui plant was on stream “every single step” of the natural gas-to-gaso-line sequence would have been commercially proven, and that the methanol to gasoline process “may have opened up a new era” for synthetic petrol production from America’s vast coal deposits. (Coal can be gasified, then converted to methanol.) Dr Lee maintained that synthetic petrol is not necessarily more expensive than petrol refined from crude oil, even with the recent drop in crude prices. “They are very close,” he said.

A Mobil background paper on the process, however, says that “it must be understood that gasoline from any synfuels process will exceed the present cost of gasoline from refining foreign crude.” Though the comment obviously does not take such factors as the weakness of the New Zealand dollar into account, crude prices are at their lowest level for some years, which would tend to widen any differential since the undated paper was written and consequently make synthetic gasoline production in the United States at least comparatively less attractive.

The assumed cost of the natural gas in the Motunui process will be allowed to vary to keep the price of finished synthetic petrol in line with petrol produced from crude at the Whangarei refinery, but Dr Lee said there was no such thing as a “world price” for natural gas because it varied enormously from

country to country and was difficult to transport in large quantities. The second-generation methanol-to-gasoline process, which Mobil says may be commercially available next year, uses a fluidised bed instead of the fixed bed that will be used at Motunui.

Dr Lee said it was decided to go ahead with the fixed-bed process in New Zealand because the need to test the fluidised-bed process would have delayed the start of the project by some years, with inflation more than cancelling out any benefts.

Mobil engineers say they see no problems in scalingup the fixed-bed process from the four-barrels-a-day pilot unit in Paulsboro to the 13,000 to 14,000 b.p.d. plant at Motunui, but they have moved up the more difficult four b.p.d. fluidisedbed pilot in Paulsboro to a SUS3S million 100 b.p.d. semi-works plant in Wesseling, West Germany. It is being funded by the German and American governments, Mobil, and ' German companies, and has an expected life of s¥a years. In the fixed-bed process, only part of the bed is used for converting the methanol to dimethylether. This zone gradually moves along the bed until the catalyst in the final zone is no longer effective — about a 30-day cycle — when the reactor has to be shut down while the bed is regenerated. In New Zealand a number of reactors will be used out of phase, with one always out of service for regeneration and maintenance. The fluidised beds do not need to be shut down, and Mobil says indications are that this process may provide higher gasoline yields and more economical heat recovery than the fixed-bed verion.

“Its major economic advantage over the fixed-bed system may be ‘its lower investment cost when scaling up to very large sizes,” according to the Mobil background paper. “Based on bench unit tests and the four b.p.d. unit, lower operating costs are also anticipated.”

The main advantage of the fixed-bed process is that the technology is well known, which simplifies scale-up designing, according to a technical paper by two Mobil researchers.

Mobil engineers have done extensive tests on the petrol produced at Paulsboro. from the fixed-bed pilot, using cars common in New Zealand.

The programme included a series of “Auntie Minnie” tests — a cold start-up followed by an immediate 2.4 km trip twice a day — to simulate that sort of driver and test for deposit accumulation. (Results were good.)

The tests have all shown that the synthetic petrol compares very favourably in all aspects with commercial premium petrols, Mobil reports. In New Zealand, Dr Lee said, the petrol from Motunui would be blended at the Whangarei refinery with petrol refined from crude oil. Anti-oxydation agents and other additives, including lead at 0.45 grams a litre (rare in the United States because of environmental considerations) would be mixed in at Whangarei, he said. Addition of the lead will raise the octane rating of the synthetic petrol from about 93 to 96. The core of the methanol-to-gasoline process is the zsm-5 catalyst Mobil developed. It converts the methanol to dimethylether by wringing out the water, which makes up 56 per cent of the weight of high-grade methanol, and rearranging the hydrocarbons into petrol. Small quantities of other substances are produced too, but 85 to 90 per cent of the hydrocarbons, which make up almost all the remaining 44 per cent of the methanol, end up as petrol, Dr Lee says. The four b.p.d. pilot plant at Paulsboro produces 63.5 per cent water and 36.5 per cent hydrocarbons, however. Dr Lee said that this was because chemical grade methanol was not needed for the process, and the methanol produced . contained more water than did chemical - grade methanol. The catalyst, a synthetic,

is called a zeolite, named after the Greek word for boiling stones: the ancient Greeks noticed that when some stones were put in a fire they appeared to boil, and deduced that the interior structure must be hollow enough to contain water.

Mobil has developed four different fixed-bed processes using zsm-5 type catalysts for such arcane work as xylene isometrisation and toluene disproportionation, and about 25 catalytic units are in use throughout the world. In all cases, Mobil says, the processes were scaled up directly from bench units and all have performed as well or better than predicted.

In the United States, the Federal Government has proposed that Mobil pay SUS 27 million to settle charges that the corporation claimed SUS92O million in excessive costs to justify prices it charged customers between 1973 and early 1981, when oil was under price control. Mobil might have over-, charged customers a maximum of SUSIOO million during those eight years, the “Washington Post” reported an Energy Department source as saying. It quotes Mobil’s vicepresident of public affairs, Mr Herbert Schmertz, though as. saying: "The claim that we might settle $920 million in claims for $27 million is totally inaccurate. In addition to the $920 million, we had an excess of $1 billion of unrecovered costs on our books. If any court had disallowed any of the $920 million, it would have been offset by the additional $1 billion in costs.”

The “Post” quotes an Energy Department lawyer as saying the proposed settlement is “unacceptably generous” because it would make it virtually impossible to press civil actions against Mobil as a result of “certain other investigations” still in progress. It also quotes criticism of the proposal by congressmen. The Administration has said that it wants to try to get back 10c to 30c’ in the dollar on overcharges.