VALUE OF COMPLETE COAL GASIFICATION

Press, Volume XCVI, Issue 28447, 29 November 1957, Page 18

VALUE OF COMPLETE COAL GASIFICATION

If New Zealand coal resources were to be used efficiently, complete gasification appeared to be the only way by which the coal industry could expand, says Mr P. A. Toynbee, of the Dominion Laboratory, Department of Scientific and Industrial Research, in the latest economic bulletin issued by the Canterbury Chamber of Commerce.

By complete gasification, indigenous sources could supply the highest grade fuel, industrial and domestic, in addition to the cheapest, coal. The installation of complete gasification processes should reduce substantially the demand for fuel oil in the reticulated areas.

“If this cheap gas is not made available, the increasing universal demand for convenience in fuel usage will continually increase the

sales of oil and reduce the sales of coal,” he says. An expanding and economic gas industry would be of great benefit to New Zealand, the bulletin continues. The demand for domestic power could be met with a capital expenditure less than a half of that required for electricity generation. The contribution of gas to the overall supply position would always be small compared with that of electricity, but the importance of the contribution of the minor partner could be greatly increased if gas was used in a properly integrated system to improve the economics, of electricity production.

“Any such expansion of the gas industry will come only from the installation of complete gasification plant,” Mr Toynbee says.

“There should be a general and gradual transition from conventional carbonisation to cyclic processes as existing plant needs replacement. The immediate installation of a Lurgi plant in the Waikato is important, not only to supply industrial and domestic power to Auckland, but to establish the feasiblity of similar installations ultimately in other parts of New Zealand. Fertiliser Production

“Complete gasification could be used also for the production of fertilisers, but it is unlikely that such production would have a great effect on the coal industry immediately. The installation of such an industry could, however, create a market for the increasing amounts of coal fines produced from screening operations at mines. The local availability of fertilisers should have a beneficial effect on the national economy of New Zealand, which depends so much on its primary production. * Before reaching his conclusions, Mr Toynbee discusses the different processes for complete gasification which could be applied in New Zealand cyclic processes, high-pressure gasification and powdered coal processes. The Lurgi process—high-pres-sure gasification—gave a very clean gas. One of the possibilities of the process was installing gasmaking plant on a coalfield and piping the gas at high pressure to the consumer even 200 miles away. The improvement in the economics of electricity production which could be realised from the integration of electricity and gas would probably justify the payment of gas subsidies, Mr Toynbee says, but if an enlightened policy was adopted for a gradual transition in methods of gas production, the gas industry could expand naturally and without subsidies, and play an increasingly important role in the power supply of the country. “The ultimate ideal is largescale production in Lurgi plants on coalfields supplying gas to the urban areas—Waikato to Auckland and Hamilton, Taranaki or Waikato to New Plymouth. Wanganui, Palmerston North and Wellington, the West Coast to Christchurch, and Otago or Southland to Invercargill and Dunedin,” he says.

Only in one case—Waikato—would such an installation, necessarily large in scale, be feasible immediately. It would not be possible to develop the others until the demand for gas in the areas increased greatly. Industrial Use Gas had a great future as an industrial fuel. The reasons for the preference of oil over coal would ensure a preference for gas over oil. Cost estimates showed that Lurgi gas and oil were comparative in price, and it was generally expected that oilcosts would increase. The development of industrial load could reduce oil imports, increase the load factor of gas usage and rapidly increase the demand in all urban areas sufficiently to justify the installation of Lurgi plants.

Summarising, Mr Toynbee says the advantages to the national economy of an expanding and economic gas industry are the avoidance of subsidies, the improvement of the electrical load factor, reduction of oil imports for domestic and industrial use, and low capital costs of powergenerating plant. Local Application

Discussing the application of complete gasification on the West Coast and in Canterbury, Mr Toynbee says that the average daily production of gas in Christchurch is about 2 million cubic feet a day. A long-term policy of gas development should increase the demand for gas in 15 to 20 years to 15 million cubic feet a day, the output of the minimum economic Lurgi installation.

Such a Lurgi plant would consume about half as much coal again as that produced in one of the larger West Coast mines. A Lurgi installation on the West Coast might use sub-bitu-minous Reefton coal if such coals could be mined in sufficient quantities. or some of the weekly caking bituminous coals of the Greymouth area.

Alternatively, it should be possibly ultimately to produce town gas from powdered coal gasification and methane synthesis. The last-mentioned scheme might be preferred eventually, as it could utilise coal fines, regardless of type. “The present surplus of coal fines on the West Coast suggests that powdered coal gasification for fertiliser production mav be an early possibility,” Mr Toynbee says. “Such a process might be integrated with town gas production. “At present, there is insuffi-

cicnt information on the reserves of Canterbury lignites to permit serious consideration of their utilisation. The only feasible method of complete gasification of these lignites would appear to be powdered coal gasification.”