NEW ZEALAND BROWN COALS

Otago Witness, Issue 3384, 22 January 1919, Page 27

NEW ZEALAND BROWN COALS

RESULTS OF RESEARCH WORK. Mr Lawrence Birks writes to the Christchurch Press: — A very important publication has recently been issued op the subject of Now Zealand brown coals, which is worthy of -wider public notice than it has received'. It is a paper by Messrs H. Rands, M.A., B.Sc. and W. 0. R. Gilling, M.A., B.Sc., National Research scholars, embodying the results of their researches carried out under the provisions of their scholarships, and it has been issued as Bulletin No. 1 of the Board of Science and Art, under the authority of the Hon. G. W. Russell, as Minister of Internal Aii'air3. The experimental investigations upon which the paper is based were carried out in the laboratories of Canterbury College, under the direction of Dr VV. P. Evans, M.A., Ph.D., Proiessor of Chemistry, wno has edited the work, thus adding to its value by the results of his judgment and experience. , . The subject is one of the utmost importance in New Zeaand, owing to the immense deposits of brown coals in the Waikato, Canterbury, Otago, and particularly in Soutliiand, and the limited extent of tho bituminous coals of the dominion. The extensive development of hydro-electric power will increase rather than reduce, the importance of the subject. For motive power and lighting purposes, hydro-electric energy will certainly replace coal fuel almost entirely, but for heating purposes on tho large scale the direct use of fuel or fuel gas must bo more economical in most cases, and for the production of tar, tar oils, fuel oils, pitch, coke, and all the innumerable by-produots of tho distillation of ,tar, including explosives, dyes, flavouring essences, hydroelectric power will only stimulate the demand for the scientific' utilisation of our fuel resources. We must look forward to the time in the early future when it will be regarded as a criminal waste to burn coal in a kitchen or boiler furnace, owing to the waste of these valuable tar products which simply go up the chimney, and blacken the neighbourhood, while much better heating service is obtainable by the use of the gas or coke after tho recovery of the tft-r products. The investigations under notice were directed towards two main considerations, both of fundamental importance:— (1) The use of New Zealand brown coals in gas producing; and (2) The low temperature distillation of New Zealand brown coals.

They do. not claim to be final investigations in any sense, but rather of a preliminary nature intended to servo as an inspiration and a starting point for fuller researches. Nevertheless, very thorough work was done, extending over several years. As an indication of the care and thoroughness, the authors state with regard to the tar distillation that "the work of the first three months, during which the many difficulties mentioned above wero gradually being overcome, is omitted altogether as unreliable." The general results arc worthy of careful study by those concerned in tho industry. With regard to the use of brown coals in gas producers, although this is commercially quite general, the authors point outimportant improve nonts which are immediately deduciblo from their experiments—particularly in the direction of more regular feeding of the fuel and the addition of water with the fuel. In the distillation, of the coals they find a return of 4 to 8 per cent, of tar as the result of low temperature distillation, which was re-distilled into light oil, middle oil, heavy oil, and pitch, and again into seven fractions in tho course of further purification. The separation of various commercial products is for further investigation. Tho brown coal tars differ from those derived from bituminous coals in being lighter than water instead of heavier. The resultant coke is distinct from that obtained in gas manufacture, as it is not subjected to so high a temperature, and still contains comparatively large quantities of hydrocarbons. This characteristic should render it much freer burning, and thus more useful as a fuel for domestic and other purposes, though, of course, not so useful for electro-chemical purposes for which, in any case, tho high proportion of ash would reduce its value. The investigations deal with practically the whole of the' New Zealand brown coals, including Kaitangata, Nightcaps. Homebush, Taupiri, Benhar, Mataura, Christies, Freemans, Jubilee, Mount Somers, Waikaka, Albury, and Conical Hill, and are thu9 of quite general value. The matter is being followed up by Dr Evans, under a science research grant, made through the New Zealand Institute, and Mr Gilling has been retained for two years' further work. It is to bo hoped that other research scholars will also find opportunity to follow up the investigation, or what would be much more effective still, that tho coalowners will combine to appoint a chemist at a reasonable salary and expenses to continue tho work indefinitely. The cost would only be a few hundreds a year. Tho re turns will certainly run to thousands, and will probably run to hundreds of thousands of pounds worth per year, as tho develop ment of hvdro-electrio power forces on New Zealand tho wider and moro effective utilisation of our fuel resources.