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1947-48 Theatre Catalog, 6th Edition, Page 428 (414)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 428
Page 428

1947-48 Theatre Catalog, 6th Edition, Page 428

Powder-Fine Coal for Heating and Power

Small-Scale Heating Applications May Come

From Research on Gas Turbine Locomotives Aspects of pulverized coal technology currently attracting attention are the gas turbine locomotivelto burn powderfine coal, its corollary potentialities in stationary and marine power, and possible adaption of its coal-operational method to small commercial and home heating installations. Immediate interest

today is in the coal-fired gas turbine railroad locomotive because the nearly $3,000,000 developmental program has railroad-coal sponsorship, but the coal fiatomizing" and iiy ash removal technique is regarded as having a broader significance.

Another development of current interest is the new method of burning crushed coal in a horizontal cyclone burner, as tested in the Calumet Station of the Commonwealth Edison Company of Chicago. An outstanding feature of this burner is its ability to burn crushed, low-grade coal having a low fusionpoint ash, with the removal of 80 per cent and more of the ash in molten form as slag tapped from the bottom of the furnace. This enables cleaner stack gases, meeting the fiy ash problem and thus abating the smoke nuisance in deference to city air polution ordinances. Its foremost field of usefulness, at least at this time, is in the big electric generating stations, although later it may prove of value in smaller industrial power plants. It was described at the December, 1946, annual meeting of the American Society of Mechanical Engiv neers by L. S. Wilcoxon, vice-president of the Babcock and Wilcox Company; A. E. Grunert, of Commonwealth Edison Company, and Ludwig Skog, of Sargent & Lundy, Chicago.

In the autum of 1944, an installation began operating, involving a steam generation unit of 150,000 to 180,000 pound steam capacity per hour at the Calumet Station of Commonwealth Edison Company.

The performance of this horizontal cyclone burner proved the principles involved to be sound, providing a simple, reliable and efficient means of burning coals at low burning temperatures to take care of high-ash, low fusion temperature coals.

The Calumet Station cyclone burner installation, arranged for natural circulation, is 8 feet in diameter and 11 feet long. It has a primary-air and coal-inlet port on the front end, a secondary air port section along the upper burner periphery, and an outlet throat section at the discharge end. A continurus slagtap opening is at the bottom. Whether horizontal or vertical, the cyclone burner is not limited to new installations but is applicable to existing units. It is not necessarily a universal burner.

The Calumet Station installation added a second, vertical burner, which is fired tangentially at the top.

So successful has been Commonwealth


Bituminous Coal Instimte

Edisonis experience with the Calumet installation that it plans to install a similar cyclone burner in its Fisk station for the 150,000-kilowatt turbo-generator that will go into service in 1949.

Reporting this development the Chicago Journal of Commerce set forth the advantages claimed for the Babcox and Wilcox cyclone burner: (1) between 80 and 85 percent of the coal ash is collected in the furnace itself and removed in molten form, simplifying ash handling and reducing the emission of dust through stacks; (2) this ash retention also reduces the amount of necessary boiler tube cleaning, permitting the closer spacing of the tubes; (3) costly precipitator equipment used in conventional installations to remove fly ash is not needed; and (4) the new furnace uses simple, easily maintained coalcrushing equipment in place of expensive pulverizers.


As for the gas turbine to burn powderfine coal, a large scale pilot plant began operating early in 1947 at Dunkirk, New York. This set-up has demonstrated the feasibility of burning powder-fine coal in the gas turbine. Continuous 24-hour run-testing proved satisfactory. During the summer of 1947 full-scale combustion-operational tests were underway at the Kaiser steel plant at Fontana, California with Northrop-Hendy Company cooperating with the Locomotive Development Committee of Bituminous Coal Research, Inc. The blast-furnace blowers provide air in the great amounts required for full-scale testing of coal burning and ash removal.

As to coal handling, the system devised for locomotives and equally applicable to stationary and marine purposes is an automatic one of crushing, drying, and pulverizing for delivery into the combustor (air heater).

The gas turbine has three basic parts: compressor, combustor (air heater), and turbine. Atmospheric air is compressed to a moderate pressure, and is heated to at least 700a Fahrenheit by burning the pnwderefine coal directly in the air. As the air temperature rises above 700 degrees Fahrenheit, the air going through the turbine produces not only enough power to drive the compressor but it also gives useful work to the output shaft. At temperatures as hot as 1,300 degrees Fahrenheit, which are safe with todayis metal alloys, its thermal efficiency can get as high as 25 per cent and the output from a single turbine can be more than 4,000 HP.

Although the thermal efiiciency is less than that of the Diesel, the operating cost using coal-should be only one-third

as much as the Diesells. It is significant that coal is not only abundantly available, but it supplies heat energy at a much lower cost than presently available from fuel oils.

The coal is transported from the bunker by a screw feeder similar to a conventional stoker, and then crushed and dried by exhaust heat from the turbine. The coal coming out of the crusher is about as coarse as percolator-grind coffee. At this stage it enters a chamber where the pressure is about 150 pounds per square inch. A coal pump does the pressurizing.

It is then fed from the pressurized storage tank as needed, and picked up by a stream of rapidly flowing compressed air which speeds it into the ffcoal atomizer? In this simple device, coal particles pass with compressed air through a nozzle where the pressure drops from 150 down to '75 pounds per square inch causing the coal particles to shatter into extremely fine fragments. These particles burn in suspension in the combustor, and leave minute bits of ash, which must be removed before the air is allowed to pass into the turbine.

So the dust-laden, hot air is put through a battery of small cyclone separators, such as those made by the Aerotec Company and the Thermix Engineering Company. This removes as much as 95 per cent of the fly ash, and elaborate investigation has shown that the remaining ultra-fine particles Will not damage the turbine blades. The disposal of this trapped fly-ash is a minor problem.

To summarize, the ability of the coalfired gas turbine to burn coal is an outstanding virtue. The gas turbine requires no water, which makes it a ffnatural" for marine as well as railroad usage and for stationary power purposes in arid or semi-arid regions. It is simple and compact. It can produce much more power in the winter than in summer, because less energy is needed to supply the compressor when the outside air is cold. Lubrication costs are negligible. Because it has few moving parts, maintenance should be low. It operates smokelessly.

It is believed that the potential usefulness of the gas turbine, especially the coal-fired, in stationary applications will be in the 1,000 to 2,000 kw. range.


A powdered-coal heating venture is underway in Baltimore which adapts the coal ifatomizingtl procedure of the coalfired gas turbine. In fact, it may be referred to as a fistep-child" of it. John I. Yellott, Research Director of the Locoe motive Development Committee of Bituminous Coal Research, Inc., has given technical advice to the venture.

The new company is the Heatmasters, Inc. If successful, it points to a great potentiality for bituminous coal in automatic heating for the small commercial,

1947-48 Theatre Catalog, 6th Edition, Page 428