WOOD SCRAPS AND SAWDUST

Hokitika Guardian, 23 April 1921, Page 1

WOOD SCRAPS AND SAWDUST

1,500,000 TONS WASTED EVERY YEAR. In West Australia alone it is estimated that 379,000 tons of wood scraps and sawdust from the timber mills are wasted every year, and that for the whole of Australia the waste would amount to 1,500,000 tons. This enormous waste is to a large extent needless, for trimmings, edgings, and slabs might be saved for the manufacture of toys and other small articles, for conversion into paper pulp, and for use as fuel. Sawdust might be treated for the recovery of alcohol, or it might be distilled for tho yield of acetic acid and acetone, among other valuable chemicals. The residuum would be a high quality of charcoal. Sawdust *nd other debris" might also be used for conversion bv means of “producers, into

power gas. In Bulletin 19, written by Mr I. H. Boas, and published under the authority of the Australian Bureau of Science and Industry, attention is directed to the fact that in the United States valuable laminated wood industries have recently been developed by means of wood material that was formerly wasted. With the aid of lamination, waggons, trusses, motor car bodies, and aeroplane propellers can be built up out of scraps that used to be regarded as worse than useless at the mills, seeing that only a small portion of them could be burnt under the ( boilers. Moreover, these built-up articles are much stronger and much less liable to warp than those cut from the solid.

In regard to the possibility of using wood waste for power fuel, it is recalled that in Sweden during the war a number of encouraging tests were carried out. It was found that oil engines could, with slight alterations, be driven with the gases generated during the distillation of wood. In this case the value of the tar recovered would offset much of the expense of tho process. The distillation was carried out in ordinary gas retorts. Mixed with coal, wood has been retorted for making town gas. Used alone the acetic acid in the wood caused trouble, but by adding a proportion of coal the ammonia given off neutralised the acid. In Australia wood mixed with 25 per cent of coal is used for the manufacture of town gas in many small gasworks. The average yield is 12,000 cubic feet per ton of the mixed fuel, and the gas generated has a calorific value of 400 British thermal units (“8.T.U.”) Some time ago, when there was a shortage of coal in Perth, the city gas company made use of white gum to supplement the gas supply- No calorific tests were carried out, but it is said that the quality of the gas—Booo cubic feet were obtained from a ton of this wood —was satisfactory. In the course of distillation, from 18 gallons to 20 gallons of tar per ton and scwt of charcoal were recovered. Sawmill waste has proved itself an efficient fuel for suction gas engine producers. Wood-producer power plants are common on the goldfields of West Australia. Green wood is cut into suitable lengths for charging the producers. In the United States halt charcoal and half “hog waste” is used with much success for the generation ot producer gas. In these circumstances tho tar is not recovered, but it is said that it gives little trouble—so little, indeed that plants have been run continuouslv for years. Mr Boas suggests that •> more general use of wood fuel in producers would be of value to timber manufacturers and others engage in wood-working industries.