Figure 3.—Comparative service of coals and lignites in gas-producer and steam-boiler plants.
It should be noted that many fuels which give poor results under steam boilers have been used with great ease and efficiency in the gas producer, which thus makes it possible to utilize low-grade coals and lignites that have
heretofore been regarded as practically useless. Several of the poorest grades of bituminous coals have shown remarkable efficiency in the gas producer, and lignites and peat have been used with great facility, thus opening the way to the introduction of cheap power into large districts that have thus far been commercially unimportant owing to lack of industrial opportunities. Experiments with “bone,” a refuse product in bituminous-coal mining, have given excellent results, showing an efficiency in the producer equal to that reached by good steam coal under boilers. Recent investigations with other low-grade fuels, such as mine roof slabs, culm, and washery refuse, have also demonstrated the possibility of using such material to advantage in the producer under proper commercial conditions.
Number and Class of Plants.
A list of producer-gas power plants recently secured indicates that at present there are over 500 such plants
in operation in the United States, ranging in size from 15 to 6,000 horsepower.
Figure 4.—Summarized data of producer-gas power plants in United States.
| No. of plants. | Horsepower. | Per cent of total number. | Per cent of total horse-power. | ||||
| Total. | Average. | Minimum. | Maximum. | ||||
| Anthracite coal: | |||||||
| Over 500 horsepower | 8 | 7,550 | 950 | 600 | 1,500 | … | … |
| 500 horsepower or less | 407 | 40,550 | 100 | 15 | 500 | … | … |
| 415 | 48,100 | 116 | 15 | 1,500 | 88 | 43 | |
| Bituminous coal: | |||||||
| Over 500 horsepower | 20 | 49,000 | 2,450 | 750 | 6,000 | … | … |
| 500 horsepower or less | 17 | 5,150 | 300 | 35 | 500 | … | … |
| 37 | 54,150 | 1,460 | 35 | 6,000 | 8 | 49 | |
| Lignite: | |||||||
| Over 500 horsepower | 3 | 7,275 | 2,430 | 525 | 3,750 | … | … |
| 500 horsepower or less | 19 | 1,725 | 90 | 25 | 250 | … | … |
| 22 | 9,000 | 410 | 25 | 3,750 | 4 | 8 | |
| All plants | 474 | 111,250 | 235 | 15 | 6,000 | 100 | 100 |
| No. of plants. | Horsepower. | ||
| Total. | Average. | ||
| Anthracite coal: | |||
| Over 500 horsepower | 8 | 7,550 | 950 |
| 500 horsepower or less | 407 | 40,550 | 100 |
415 | 48,100 | 116 | |
| Bituminous coal: | |||
| Over 500 horsepower | 20 | 49,000 | 2,450 |
| 500 horsepower or less | 17 | 5,150 | 300 |
37 | 54,150 | 1,460 | |
| Lignite: | |||
| Over 500 horsepower | 3 | 7,275 | 2,430 |
| 500 horsepower or less | 19 | 1,725 | 90 |
22 | 9,000 | 410 | |
| All plants | 474 | 111,250 | 235 |
| Horsepower. | Per cent of total number. | Per cent of total horse- power. | ||
| Mini- mum. | Maxi- mum. | |||
| Anthracite coal: | ||||
| Over 500 horsepower | 600 | 1,500 | … | … |
| 500 horsepower or less | 15 | 500 | … | … |
15 | 1,500 | 88 | 43 | |
| Bituminous coal: | ||||
| Over 500 horsepower | 750 | 6,000 | … | … |
| 500 horsepower or less | 35 | 500 | … | … |
35 | 6,000 | 8 | 49 | |
| Lignite: | ||||
| Over 500 horsepower | 525 | 3,750 | … | … |
| 500 horsepower or less | 25 | 250 | … | … |
25 | 3,750 | 4 | 8 | |
| All plants | 15 | 6,000 | 100 | 100 |