§ 42. Mr. WELLOCKasked the Secretary for Mines if he will state the estimated loss per ton of coal used of the most economic processes of coal carbonisation, whether at low or high temperatures, on mass production lines?
§ Mr. SHINWELLLow temperature carbonisation of coal is not being undertaken on mass production lines. In the case of high temperature carbonisation processes there is, so far as I am aware, no financial loss per ton of coal used. If however my hon. Friend means by "loss" the difference between the potential heat in a ton of coal and that generated by burning the products from the carbonisation of a ton of coal, then on that basis the loss in the most modern practice is from 10 to 15 per cent. This figure includes the heat value of the fuel used for heating the retort, and allows for the heat recovered by the use of waste heat boilers etc. In some processes the heat is obtained by the combustion in the retort of some of the material. In such cases the heat loss may be as low as 8 per cent., but the gas produced will be of low calorific value.
§ Mr. HARDIEIs there no record of any plant working by low temperature carbonisation which has a lesser loss by radiation than any high temperature plant; and can the hon. Gentleman say whether the products of the low temperature system are not as valuable as those of the high temperature system?
§ Mr. SHINWELLThere may be such records as those to which my hon. Friend refers, but they are not in my possession.