Gas To The Aid Of Coal PROMISE OF HIGHPRESSURE SYSTEMS

Press, Volume XCIX, Issue 29268, 28 July 1960, Page 14

Gas To The Aid Of Coal PROMISE OF HIGHPRESSURE SYSTEMS

[By E. V. FRANCIS in tin “Daily Telegraph”) [Reprinted By Arrangement!

A year ago I suggested that the mountains of small coal, then embarrassing the Coal Board, could have a big future, given investment in plant to convert it into dean, smokeless solid fuel. Well, the mountains are still there, and the fuel experts say they have been over-optimistic in their estimates of demand for fuel of all kinds.

But there is another possibility which is now being explored. It is to convert even the poorest coal completely into gas, which can be distributed at high pressure and leaves no unwanted residue of coke to be sold often at a loss. Much has been said about coal as a source of chemical raw materials for the production of almost anything from cosmetics to aspirin and plastics. But the most obvious by-product, Britain's nearest equivalent of natural gas. has been virtually ignored by our chemical engineers. Coal gas is made by conventional methods of carbonisation which had ceased to be capable of technological improvement more than 50 years ago. The gas industry and, at one remove, the coal industry, have been handicapped by this enforced stagnation in the technology of conventional gas-making in face of the fast-growing challenge of oil. True, the Gas Council has secured great economies by rationalising existing methods of production. Output has been concentrated on fewer and larger plants. Regional grids have improved the efficiency of gas distribution. Some 30 new plants have been installed to produce gas on favourable terms from the residual fuels and tail gases of the oil refineries. In this way the industry has managed to offset increases in labour and coal costs by some £l5 million. Industrial Dinosaurs But the greater part of its £2OO million investment in plant since nationalisation has necessarily been devoted to a nineteenthcentury technique of carbonising coal. With the need to concentrate production, the conventional gas works, symbolised by Beckton, in East London—the biggest of its kind in the world—have grown ever more elephantine. They are industrial dinosaurs, condemned by the sheer weight of metal with which low-pressure gasification has had to be invested. Modern chemical technology has meanwhile opened up a new line of advance in the extraction of gas from coal by high-pressure processes. The gas industry’s researches have now brought it to the stage at which it will bring into operation at Westfield later this year Britain’s first high-pres-sure plant for the total gasification of low-grade Fifeshire coal. This £6l million venture by the Scottish Gas Board is potentially of great significance for the coal industry. Whether the National Coal Board can, as Mr Robens thinks, stabilise its future at the 200 million-ton mark, depends partly on how much more or less coal than the present annual 24 million tons the gas industry will require for its development. This depends, in turn, on how rapidly the gas industry turns from antiquated to modern methods; from low-pressure carbonisation of expensive gas-coal to the high-pressure gasification of cheap small coal. What is even more important is that the gas produced by the chemistry of high pressure is able to challenge oil for heating purposes in a way that solid fuel cannot Thanks to new techniques of welding and pipe-laying it can offer all the advantages which have made natural gas in the United States and, more recently, in France a major source of industrial energy and domestic central heating. Cheap Distribution

It can be cheaply distributed by long-distance pipe-lines. It is superior to solid fuel in that it requires no handling, and has the advantage over oil that it can be tapped directly from the mains without needing domestic storage tanks or pumping equipment. It was to verify these wider claims that I went to Westfield. The new gas plant—one might almost call it a coal refinery—is not due to go on stream until the autumn. But the nature and scope of its operations are already clearly discernible. Small coal from the adjacent open-cast working of a 20 millionton deposit will be fed in at the top of the gasifiers—each a welded steel pressure vessel nearly 10ft wide and 28ft long—where it descends to meet an upward stream of oxygen and steam at a temperature of 800 degrees and a pressure of 3701 b per square inch. Not only is the small coal completely gasified, but some of the hydrogen elements, fusing with the normally residual carbon, produce methane. This in turn provides a gratuitous boost to the process of gasification. The gas is then passed through various purification towers which retract the benzol, ammonia, light oils, and tar. What finally emerges is gas compressed at 2501 b per square inch, ready for distribution by high-pressure mains to various towns where it will be brought down to 151 b per square inch for home and factory use. Four such high-pressure gasifiers at Westfield will alone produce one-fifth of Scotland's gas consumption. New Main System

The high-pressure main connecting Westfield with Coatbridge will be extended at both ends to Dundee and Ayr, with a branch to Edinburgh and Galashiels. This will provide the industrial belt of Scotland with an advanced md integrated gas supply system, enabling the output of the 30 existing gas works to be replaced by the Westfield plant with the aid only of four conventional gas works by 1967. Westfield, by providing a new outlet for 1000 tons daily of lowgrade Fife coal, will help to compensate for the exhaustion of Lancashire’s reserves. It will also greatly help home-produced gas to meet the growing competition of Middle Eastern oil for domestic and industrial heating. How competitive it will be remains to be seen. But the prospects, already encouraging, would be much enhanced if the Coal Board cut its prices of inferior small coal. The Westfield plant can operate on the cheapest run-of-mine coal.

whereas the conventional gas works requires top-quality gascoal. Moreover, it will extract 65 per cent, of the original therms in the coal, or double the rate achieved by the traditional carbonisation plants. Again, the long distance over which this highpressure gas can be transmitted unaided is held to represent a saving of nearly Id a therm in distribution costs. As for costs, nothing more is claimed for the Westfield plant than that the cost of its highpressure gas, including capital charges, will compare favourably with that of gas produced by a modern conventional plant excluding capital charges. More than this would be required to induce the Gas Council to commit its whole future to this development. Nevertheless, the industry has within its reach a new and revolutionary process, the full potentialities of which can only be revealed in the light of operating experience. The major problem is to make such a technological breakthrough in the use of the N.C.B.S Midlands coal, the most cheaply produced in Western Europe and the major element in the country’s unsold stocks. The gas industry, after long experiments with the various types of coal, has already embarked on its second high-pressure project at Coleshill, near Birmingham, to be completed two years hence. This will form an essential part of a regional grid for the Midlands, to be linked eventually with other regions. It is likely to take the best part of a decade, however, before high-pressure gas connexion between the Midlands coalfields and London is reached. German Experience The chances of the industry's being able to get ahead with investment in further high-pressure plants depend on the economics of operating these new plants, and the progress achieved in research into the application of this process to particular types of coal. The Germans invented this Lurgi process in the 1930’s to utilise their vast reserves of lowgrade brown coal. They used it to great effect in Hitler’s drive for oil by hydrogenation. Australia and South Africa have each successfully operated a plant of this type for some years. Although we are now as far ahead as any country in research on coal gasification, much has still to be proved in its application to our own particular types of coal. What is important is that this new process opens up to the gas industry an escape from the dead-end of conventional methods of carbonisation.

Now that the fuel shortage has given way to plenty, both the gas and coal industries are sharply confronted with the full challenge of oil. It is a challenge of technical achievement as well as prices. If the gas industry is not to fall behind in the race for the expanding market for energy, and domestic central heating in particular, it needs to throw its full weight behind research and development in this field. Its present spending of £2J million on research is certainly not over-ambitious.

Compared with this urgent challenge, some of the Gas Council’s other aims, extending to the importation of frozen methane gas from the Gulf of Texas, may seem rather grandiose.