USE OF BY-PRODUCTS

Manawatu Standard, Volume LVII, Issue 180, 1 July 1937, Page 8

USE OF BY-PRODUCTS

AT CITY GASWORKS. EXTRACTS FROM COAL. References to the recoveries mrule from waste in Birmingham, published in the “Standard” this week, draw attention to the fact that in Palmerston North every economic method is used at the gasworks to recover valuable byproducts in the process of manulacturing the gas .to be used in city homes. All are familiar with the fact that coke is one of the by-products so obtained, but in addition tar is secured and that is distilled to give a tar-oil which is used as a wood preservative, a weed-killer and as a spray lor trees. Although it is not considered economic to install the necessary machinery oil account of its cost, there is a further process by which ammonia could he extracted from the liquid that is produced in washing the gas prior to its going through a further purifying process before reaching the mains. The heavy liquor which results from the passage of much gas is disposed of by soakage in a sump-hole in Palmerston North, as it could not ho allowed to reach any (waterway. In Christchurch there is a I processing plant, which is understood |to he the only one in New Zealand, which could handle the liquor to extract the ammonia, but on account of the bulk of the fluid, and its weight, itt is not an economic proposition to send it to the southern city for treatment. I Numbers of the gas producing I plants in towns in England have fitj ted apparatus by which benzol is reI covered from the gas in washing it (with oil. The benzol, which is similar to benzine, but lias not the petro- | leum base of benzine, is distilled from jtlie oil and is sold commercially as a motor fuel. The process is stated to jbe a relatively inexpensive one and simply takes the benzol, then in a gaseous form, out of the household gas. ITt is a natural result that when the j benzol gas is extracted there must j be more gas made to make up the de--1 ficiency in bulk, and the increase, is j stated to lie five to ten per cent. I rom |one to two ’.gallons of lienzol are re--1 covered from each ton ,df coal used and, judging by the number of plants j installed in conjunction with gasworks in England, it is expected that similar plants will be installed in. New Zealand before any great length of time. Waste material which goes eventually into the city’s destructor at Awapuni is also used to a certain extent, for the destructor fire is employed to heat specially constructed boilers which give the motive power to a steam turbine-generator. The generator produces electricity which is employed in the chilling rooms of the municipal abattoirs.