POWDERED COAL

Dominion, Volume 12, Issue 210, 30 May 1919, Page 5

POWDERED COAL

IS IT ECONOMICAL? Increased attention is being given to the use of coal in the form'of very fine powder (states the Melbourne "Age"). Theprincipal claim made for this fuel is that it enables low-grade black coal and brown coal to bo used to the best advantage, but the powdering process is iu some quarters thought to be worth considering from the viewpoint of reducing transportation and handling costs, even in tho case of high-class coal. The following advantages, it is claimed, can be derived by the carbonisation of coal:—Complete combustion, and tho utilisation of every atom of energy coal contains. Highest temperature possible witli the fuel used for perfect combustion. Utilising low-grade coals, waste mine washings, and screenings, through the system of conveying, drying, pulverising, mixing, feeding and firing coal, and by regulatirfg the air supply. Solving of the smoke problem. A great saving of fuel by the reduction of. the amount required to generate- tho. same amount of heat, deduction in the cost of transportation, because less fuel is used for a given result. Fuel supply which gives instant response to varying heal' requirements. Control of heat production, which can be adjusted to accommodate load requirements. Seduction in the cost of handling fuel, because the operation becomes practically automatic, eliminating firemen and stokers. Powdered coa.l thoroughly carburised can be so perfectly controlled that it can be turned on or of)' like gas or oil. '.Reduction of storage reserve requirements.

In it letter answering inquiries made by a. large copper-mining company in South Australia, the Powdered Coal Engineering and Equipment Co., of Chicago, states that the history of the reverbatory furnace in the United Slates shows an increasing tendency towards powdered coal firing. The company says that, started I firs-t in 19)2 at the works of the Cana- ! dian Copper Co., Ontario, and taken up later by the Anconda Copper Co., MonI tana, the employment of powdered coal as a fuel in copper ,1-everbalories has shown such, great fuel economies, together with increased furnace output, that smelter after smelter has been changed over to its use. In referring to the operations of the lfiver Smelting and Refining Company, at Colorado, the Chicago letter say*:—"This company was tiring a small reverbatory •IS feet long and smelting a complex zinc copper ore. The fuel used at the lfiver Smelting' and- Refilling Company has the following analysis-.—Moisture, 5.15 per cent.; ash, (i.12 per cent.; volatile matter, 40.19 per cent.; fixed rnrbon, 45.54 per cent.; li.'fYO., 11.83G per cent. The healing value of (lie coal is .very good. 11, however, contains a laminated and low-melting ash, which made tttoker and hand firing auualler of great difficulty. The ash. being disseminated through the coal in fine laminations, cannot be removed from it 'by any ordinarq method of preparing coal. When handfired or stoker-fired the ash melted, ran down on tho grates, froze there, and led to constant interruption in operation. The company shipped ten tons of this coal to our engineering development plant in Chicago. It was demonstrated immediately that this fuel could bo burned with utmost satisfaction in powdered form. Subsequently wo put in a. powdered coal installation for the company, fo starting this up we found that tho furnace must be immediately lengthened fo be at least. GO feet, due to the temperature of the exit gases being so-much litjrhor because of ."efficient combustion heretofore not attained. Last autumn the furnace was ngnia lengthened to 90 feet, with corresponding greater output, but the total amount 'of fuel burned per dnv was Jiot changed; Ihe increase in length of the furnace, bad flic effect of raising furnace efficiency by utilising still better the gases from tho flame. The fuel ratio under hand-firiug was"approximately 1 2-! l ton of coal to one ton of ore. After increasing the length of the furnace twice, the fuel ratio is one lon of powdered coal jo 51 tons of ore." The officials of the Kiver Company consider the installation an absolute success. \