Part 40

Relative economies of steam and gas power plants at St Louis in the conversion of 1 pound of coal, containing 12,500 British thermal units, into electricity.

==================================+====================+==================== | Steam Power. | Gas Power. +---------+----------+---------+---------- | British | | British | | thermal | Per cent.| thermal | Per cent. | units. | | units. | ----------------------------------+---------+----------+---------+---------- Losses in exhaust, friction, etc. | 11,892 | 95.14 | 10,812 | 86.5 Converted into electric energy | 608 | 4.86 | 1,688 | 13.5 +--------------------+---------+---------- | 12,500 | 100.00 | 12,500 | 100.0 ----------------------------------+---------+----------+---------+----------

The ratios of the total fuel per brake-horsepower hour required by the steam plant and producer-gas plant, under full load, not counting stand-by losses, are presented below as derived from 75 coals, 6 lignites, and 1 peat (Florida).

The curves in Figure 3 show graphically the great economy secured with the producer-gas plant. The figures for the producer-gas tests 361 include not only the coal consumed in the gas producer, but also the coal used in the auxiliary boiler for generating the steam necessary for the pressure blast--that is, the figures given include the total coal required by the producer-gas plant.

Ratios of fuel used in steam and gas plants.

Average ratio, coal as fired per brake-horsepower hour under boiler to coal as fired per brake-horsepower hour in producer 2.7

Maximum ratio, coal as fired per brake-horsepower hour under boiler to coal as fired per brake-horsepower hour in producer 3.7

Minimum ratio, coal as fired per brake-horsepower hour under boiler to coal as fired per brake-horsepower hour in producer 1.8

Average ratio, lignite and subbituminous coal as fired per brake-horsepower hour under boiler to lignite as fired per brake-horsepower hour in producer 2.7

Maximum ratio, lignite and subbituminous coal as fired per brake-horsepower hour under boiler to lignite as fired per brake-horsepower hour in producer 2.9

Minimum ratio, lignite and subbituminous coal as fired per brake-horsepower hour under boiler to lignite as fired per brake-horsepower hour in producer 2.2

Average ratio, peat as fired per brake-horsepower hour under boiler to peat as fired per brake-horsepower hour in producer 2.3

In considering the possible increase in efficiency of the steam tests with a compound engine, as compared with the simple engine used, the fact should not be overlooked that a corresponding increase in the efficiency of the producer-gas tests may be brought about under corresponding favorable conditions. Not only is the producer passing through a transitional period, but the gas engine must still be regarded in the same light. In the larger sizes the vertical single-acting engine is being replaced by the horizontal double-acting engine. Other changes and improvements are constantly being made which tend to increase the efficiency of the gas engine, as compounding and tripling the expansions have already increased the efficiency of the steam engine.

As has already been stated, the gas engine used in the tests here reported is of a type that is rapidly becoming obsolete for this size, namely, the vertical, three-cylinder, single-acting.

A brief consideration of these points will lead at once to the 362 conclusions that a comparison of the producer-gas plant and steam plant used in these tests is very favorable to the former, and that any increase in efficiency in the steam tests that might result from using a compound engine can be offset by the introduction of a gas engine of more modern type and a producer plant designed to handle the special kinds of fuel used.

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. 363 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.

=========================+=======+==================================+ | | Horsepower. | |No. of | | |plants.| | | +-------+--------+--------+--------+ | | 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 | +=======+=======+========+========+========+ 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 | +=======+=======+========+========+========+ 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 | +=======+=======+========+========+========+ All plants | 474 |111,250| 235 | 15 | 6,000 | -------------------------+-------+-------+--------+--------+--------+ =========================+=======+======= | | Per | Per | cent | cent | of | of | total | total | horse- |number.| power. -------------------------+-------+------- Anthracite coal: | | Over 500 horsepower | ... | ... 500 horsepower or less | ... | ... +-------+------- | 88 | 43 +=======+======= Bituminous coal: | | Over 500 horsepower | ... | ... 500 horsepower or less | ... | ... +-------+------- | 8 | 49 +=======+======= Lignite: | | Over 500 horsepower | ... | ... 500 horsepower or less | ... | ... +-------+------- | 4 | 8 +=======+======= All plants | 100 | 100 -------------------------+-------+-------

Data secured from this list are summarized in the table on the 364 previous page according to the type of fuel used, and separately for all plants above 500 horsepower and for those not exceeding 500 horsepower.

It will be observed from this table that about 88 per cent of the total number of installations in this country are operating on anthracite coal (a few using charcoal or coke), and that bituminous coal and lignite are used in the remaining 12 per cent. Of the total horsepower approximately 57 per cent is derived from bituminous coal and lignite and 43 per cent from anthracite coal, charcoal, and coke. In point of size it will be noted that the bituminous plants average 12½ times the size of the anthracite plants.

In 1906 a large number of these plants were carefully inspected in order to secure definite information from the owners and operators regarding the more or less successful operation of such installations. Similar inspections were made in 1908.

Deductions from Visits of Inspection.

The deductions made from the visits in 1906 were as follows:

1. The plants as a whole are giving remarkable satisfaction considering the very brief period of development that has passed since the introduction of this type of power.

2. The most serious difficulty seems to arise from the lack of competent operators to run the plants rather than from defects or troubles in the plants themselves.

3. Incompetent salesmen are undoubtedly to blame for serious misrepresentations and misunderstandings.

4. The neglect shown by some manufacturers in respect to their plants after they are installed and paid for has not been farsighted, and the failure of the manufacturers to give the purchasers or operators of 365 plants full information regarding their construction and method of operating has certainly been detrimental to the business.

At the present time (1910) the following modifications might be advantageously made to the above statements:

1. Unchanged.

2. This situation still prevails, although there are many more competent operators today than three years ago. Time will eliminate this difficulty.

3. With stronger companies this situation is greatly improved.

4. Experience has shown that such neglect produces serious troubles and financial loss to the manufacturer, and a very decided change for the better has developed in the last few years. There are, however, a few small concerns still operating in the producer field on what may be considered a false basis.

Centralization of Power Development and Distribution.

Central stations for power and lighting are springing up all over the country. Electric lights are now in general use in towns numbering their population by hundreds only. Electric transmission for street-railway service is practically universal and electric power for shop drive is in great demand. The substitution of the electric locomotive for the steam locomotive for terminal service and even for line duty by several leading railway systems is no longer a mere expectation but is an every-day working reality.

These changes and developments in every section are, to a large extent, tending to do away with the individual small steam equipment, whether stationary or locomotive, and are bringing to the front the central power station, ranging in size from lighting and pumping plants of less than 100 horsepower in the smaller towns to those of 100,000 horsepower or more required to meet metropolitan demands. 366

European Examples of Advantageous Location.

In the development of central power plants and the reduction of the cost of power, the producer-gas power plant is an important factor. In this connection the question of locating such plants directly at the mines is well worth careful and unbiased attention in the engineering profession. The advantages to be derived from such a location have already attracted the commercial interests of Europe. As examples worthy of thoughtful consideration, the general conditions of operation of three typical European installations are here described:

Plant A.--This plant, although not situated directly at the mines, is but a short distance away, and the company owning the plant also owns the mines from which the fuel is secured. The plant is of the Mond by-product type and consists of eight pressure producers of 2,500 horsepower each. The fuel used is a run-of-mine bituminous coal said to contain 8 to 9 per cent ash and 1 to 2 per cent sulphur. This would indicate that they are utilizing the best grades of coal from their own mine in the local gas plant and allowing the lower grades to remain unmined, a fact which I verified before leaving the plant.

The plant is designed for the recovery of the sulphate of ammonia and for supplying gas to the neighboring towns for both metallurgical and power purposes. As one unit is always held in reserve, the plant is called 16,000 horsepower. The main distributing line is 3 feet in diameter, and at the time of my visit there were 37 miles of main, the longest single run being 6½ miles. Each producer gasifies, on an average, 20 tons of coal per twenty-four hours. The report of the engineer in charge indicates that the plant had been in operation twenty-four hours a day, seven days a week, for two and one-half 367 years without a shut down.

Plant B.--This plant, which is located in the center of a peat bog, proved of especial interest. It has a capacity of 300 horsepower only, and is about 3 miles from the town to which the electric current is supplied. One-half of the plant (150 horsepower) was installed in 1904 and the remainder in 1906. This is probably the first as well as the smallest producer-gas installation to be located at the mine and transmit high-voltage current to a point some distance away. This installation, in 1909, consisted of two suction producers (special peat type) rated at 150 horsepower each, and two horizontal twin single-acting four-cycle gas engines of 150 horsepower each, direct connected to alternating-current three-phase generators, which were running splendidly in parallel at the time of my visit. The 3,000-volt current is transmitted to the town, where it is used during the day for lighting shops and for shop motors. At night the plant supplies the lights for the streets and residences. The charge for residence light is 9 cents per kilowatt hour. Both units are in operation from 5:30 a. m. to 6 p. m., and one continues to 11 p. m. each day.

A 35-horsepower peat machine is used for preparing the fuel. This is driven by an electric motor supplied with current from the power plant on the bog. As only 750 tons of dry peat are required per year there is no attempt to work the plant to its maximum. Local farmers are employed and they work as little or as much as they please, as there is no difficulty in getting out all the peat needed for a year during the working season, which in this locality is from April 15 to September 1. As a result 14 men are employed more or less of their time. They receive about 50 cents per day each and get out about 20 tons of peat per day.

Coal at this point in Europe costs $3.75 per ton. The dry peat 368 delivered on the operating platform of the producer plant costs only 80 cents per ton.

Plant C.--This plant is installed at the collieries. At the time of my visit it was under full operation, using roof slabs that gave little indication, on casual inspection, of containing any combustible material. It was claimed that this fuel averaged over 60 per cent ash--a claim which seemed entirely reasonable. At the time of this visit (1908) the producers were not only supplying a number of furnaces with gas, but were also operating a 1,000-horsepower and a 250-horsepower gas engine. A 500-horsepower engine was being added to the equipment. The engines in use were direct connected to electric generators. The 10,000-volt current is used for operating the local mine machinery and also for furnishing lights for neighboring towns and power for a street railroad. The plant was reported to be using over 100 tons of this low-grade fuel per day.

Favorable Conditions in the United States.

In the United States cheaper power is constantly sought. The water-power possibilities of the country are being realized and the hydro-electric power plant is a wholesome cause of competition. The supply of fuel of marketable grades is not unlimited. Prices for such fuel must necessarily increase. The cost of transporting coal from the mines is high, and the possibility of obtaining a sufficient supply of cars to handle low-grade fuels is questionable. The power demands of the country are increasing, and this power must be developed at a reasonable cost. The time is approaching when the cheapest fuel obtainable must be used to the best economic advantage in order to develop power at a unit cost consistent with commercial progress.

Consideration of the conditions indicates that in order to keep the 369 price of power developed from fuel down to a consistent figure--

(a) Grades of fuel which warrant transportation, or which may be defined as “marketable,” should be used with the greatest possible practicable economy.

(b) The very large percentage of coal of so-called low grade which today is left at or in the mine must be utilized.

(c) Advantage must be taken of the large deposits of lignite and peat which are found in many sections of the country.

It is undoubtedly true that in general, under conditions which do not require the use of steam for other than power purposes, the producer-gas power plant meets the requirements of (a).

At present the only method of advantageously handling the fuels mentioned in (b) and (c) is in the gas producer, and the utilization of these lower grades of fuel on an extensive scale demands concentration of the power plants within close proximity to the fuel supply.

The logical conclusion from a careful study of the producer-gas power situation is that the time is not distant when financial interests in power production will be directed toward the centralization of the producer-gas power plant at the mines and the distribution of the energy developed either by high-voltage long-distance electrical transmission or by pipe systems for conveying the gas.

EFFICIENCY IN SHOP OPERATIONS. 370

BY H. F. STIMPSON.

[Consulting Efficiency Engineer, New York. Published in The Iron Age, Jan. 6, 1910, and reproduced by special arrangement.]

Managers of industrial enterprises will undoubtedly agree that there are few qualities which are more to be desired in equipment, methods and men than that of efficiency. From an extensive study of this subject in various parts of the country, together with interviews and correspondence with several hundred concerns, the writer has become convinced that there is a general lack of definite comprehension of what efficiency is, whence it springs, how it may be measured and developed and the results which its cultivation will produce. The object of this monograph is an endeavor to throw some light upon these things and to afford a new viewpoint from which to study industrial operations.

The Evolution of Industrial Management.

In the first place we must realize that the management of industrial enterprises is in a state of evolution. The tremendous growth of the past few years has caused certain previously satisfactory methods to become inadequate to present needs. Many details which in the days of smaller affairs could be absorbed by personal inspection and mentally stored for use when needed must now, because of their very volume, be made matters of record.

The character of these records has much to do with their value. Because financial records are so ancient they have exerted an undue influence upon the character of all other records. While under our present civilization, the ultimate object of industrial operations is to create financial profits, there are many highly important records which cannot be adequately expressed in terms of money. The business 371 of manufacturing consists of a repetition of mechanical operations. Mechanical operations necessarily involve considerations of weight, distance, time and effort, but not of money.

The reason for the failure of so many cost systems to serve the desired end is that they are based upon a wrong unit. These systems become useful only beyond a certain point. Other systems have been the result of a blind craving for aid, but being without broad underlying principles and not properly tied together and simply, in many cases, disjointed attempts to improve isolated details, they too have failed. The result is that attempts by specialists to improve industrial conditions have been often looked upon with suspicion and this is not altogether without reason. These very failures, however, have drawn the attention of men in certain lines of engineering to the rapidly developing needs of manufacturers. They have attempted to solve the problems by the use of engineering instead of by accounting methods, and the results which have been attained prove conclusively that a material advance has been made.

What Is Efficiency?

With this understanding of the present conditions, let us consider what efficiency really is. It has been defined as “the ability to produce certain results,” and this at the very outset necessitates the existence or creation of a standard of measurement. Our perception of efficiency, therefore, is correct only in proportion to the precision of the standard, which must be accurately developed from data which are not only exact, but complete. A machinist, believed to be operating at high efficiency, was observed while turning a shaft. His cut, feed and speed seemed to be beyond criticism. When the shaft was finished, however, he had to spend half as much time in hunting up a chain and pad to remove the shaft from the lathe, as he had taken in 372 turning it. This cut his actual efficiency from 100 per cent down to 87 per cent, yet the man was not at fault. His normal work was to operate a lathe and not to hunt for things which should have been provided for him. The points to be observed here are not only the importance of using the right standard of measurement, but that the efficiency of the man depended very largely upon his surrounding conditions over which he had no control. These conditions depend upon the efficiency of the management in securing proper equipment from the owners. This in turn depends upon the efficiency of the management’s records in enabling it to state clearly and accurately what increase in output and consequently in profits will result from improving the conditions--thus justifying the expenditure required. We see from this that the true standard is not the possibility under existing conditions, but that which can be obtained under other and more desirable conditions.

Managerial Opposition to Change.