THERMAL HEAT AS INDUSTRIAL FUEL

Rotorua Morning Post, Issue 5295, 7 January 1947, Page 6

THERMAL HEAT AS INDUSTRIAL FUEL

P0SSISILIT3ES DE3ATED CA'i-i BE vm rci GENOATaJJ ?• Ti:; uiecch'sful sinking >f i !it* *k-.t par' hot water gusher in t.iv Eul;« nia i t, bohind ihe Borough Transit Camp, has a:wi'f ed a food cleal of comment .t?j j »r i*t:~ of New Zealand. •s' .j.;- H "'r -.v'-o has been f 'v 11-hi: 5:tg in the Auckland ■./.iL, f-j/ many years, 4-t atea in a ie.tcr to the Editor cf the New Zealand He.-aiJ, that thore sj,. V i ! : ;.> why Poiopt-a's ■h'.T, al heat ahoald nct be pat to mere naticn-w.de use. ' Is there any reason" he ashs, "why advantage should not he taken cf ihe hot water ^v.. •*•»- rMty?" Jfv-m ■: was ro •nd impraeticable to use the water in its natural state, he contina.es, it corld be a sed to gsnerate steam which coukl drivc steani engines er tuvhin r aftcr it ha*i been i Buperheated by the use cf coal. Intei*est has also been revived in j Welling'ton, where the report issued : by Mr. N. Modriniak, of the Depart- j ment of Internal Affairs, issued in j 194-4, is recalled. Mr. Mcdriniak, rp to that time, had logged and mapped 65 bores. The bores arc f-ound to yield hot water, steam, or bofh, says the report. It reviews in some detail the -content of the waters (there are focnd to be both alkaline and acid waters), their origin, and the geological character of the earth from which they are obtained. I Cannot Miss Water Drilling results suggest that it is I impossible to miss water in Rotorua, I and in certain areas impossible to miss hot water. In the Ohinemutu-Hospital-town area, flcws of steam and hot water aro generally cbtained. In the area to the south, warm to hot water may be obtained, but towards Whakarewarewa again the temperature rises. It is possible that in tlie southern part of the town steam may be ob.tained by drilling to greatcr depth than the present bores havc gone. Among the problems to be solved in maintaining the "life" of a bore is t"he coi-rosion of the bore easing and piping by the acid waters. Till some non-corrosive materials can be evolved, alleviation of this troubles achieved by employing outer and inner casings with a csment grouting of the caviiy, states the report, which procecds to discuss metlicds of doing this. Dealing with future developments in utilising thermal heat, the report says that the present practice, now largely limltcd to the Rotorua district, i slikely to be cxtended in other similar localities as advar.ces are madc in economy and effi/iency. Improvf- ri nt? in Ce.-Jgn cf instal.mcji.fc vUi '•c cx cctou us oxpcricnce grows. It is unfovamate, says the report, that the State Department housing groups are not in areas suitable for the drilling of steam bores so far as cxperiments show. Othervvi.se it •wv 1 ' have been possihie to recome. nd that a gro :.u of ihcse houses be heated and supplio.I \ ith hot water from a sinc-o bore as an experiment in group utilisation. It suggesi? chat attention in future shcild be pr.id to this possibility in any housing or town planning scheme that coneerr-s such thermal arcas. Industrial Uses Industrial users cf thermal heat at present are few, and as almost all the availa'ole town area suitable for drilling of steam bores is closely occupied, major industrial develf pmer.ts probably will take place outside the town area. Large quanties of low grade heat are readily available in a cheap form, but there are other industrial factors to be taken into aceount. In cases where raw materials are bulky and transport problems intervene, the saving in fuel may not be spffiej^nt to offset these factors. stries using raw materials of alk or local origin may ftnd the geothermal resources desirable rofitable. i drying of timber is a case in and an officer of the departmt was investigating the possibility developing a suitable type of heat jmp to ecnvert large quantities of nv-grade heat into smaller amounts a high-grade heat . It has already been demonstrated by rmdertakiujgs in Italy that it was possible to generate electricity at steam plants powered by natural steam and then reticirlate the electric power. iMr. F. E. N. Tuck, a mechanical engineer of the Public Works Depart-

ment, while serving with the armed forces in Italy, had visited Larderello at the suggestion of the New Zealand Government. He had been helped in collecting data by Mr .D. E. Jobley, who had examined the chemical section where various chemicals were extracted from the steam. The report compiled by Mr. Tuck fJhowed that thie (Laiderello^ No. ;2 J plant generated 90,000 K.V.A. and the [ Castelnuovo No. 2 plant 69,000 K.V.A. I their combined- output being equivalent to that of Arapuni. Plans were under way to build a third plant at Larderello to generate | 120,000 K.V.A. | The geological structure of NgaI wha Springs in North Auckland was similar to Larderello, and apparently I well suited as a site for an experij mental well. One to a depth of about 1000 feet J would be the first step necessary to I investigate the possibility of tbe ; scheme. There also were in Italy small gen- ' cratin g plants of a few thousa* «l | K.V.A. capacity, and it was possible | for a small district or industrial con1 cem to be powered- by such a plant at j any of the thermal areas. j Several chemicals were produced ' either directly or indirectly from j steam at generating plants in Italy. 1