Search Documents

By J. D. Forrester, Erich Sarapuu, T. C. Cheasley

John G. Tripp-—The concept of converting fuel deposits in-situ to useful forms of energy and chemical raw materials has important possibilities as a means of stretching out our fuel resources. The authors have worked in this field for years and in fact are among the pioneers in developing in-situ techniques based on underground electrocarbonization. Their efforts have aroused great interest in this subject and their contributions will undoubtedly gain even more significance as time goes on. The 4 to 5 billion tons of petroleum are proved reserves, that is, they are completely defined and could be produced economically with present methods of recovery. Reserves of coal, tar sands, and oil shale shown in Table I are not equivalent to proved reserves as the term is used in the oil industry. Incidentally, the 4.3 billion tons of oil shown in the tabulation is equal to about 28 billion barrels of oil and, therefore, presumably does not include reserves of natural gas liquids estimated at about 5 billion barrels. The relative comparisons would be more complete if these liquids together with the reserves of natural gas were included in the tabulation. It is stated in the report that production costs of the order of 10c per million Btu's could be expected from a large industrial electrocarbonization installation. The authors state that the operation probably could be operated successfully and at a profit. I would like to express my view that for the operation to be profitable extremely favorable conditions would have to prevail. For example, the coal seam would have to be thick and close to the surface in order to minimize drilling costs; the deposit should be dry and so situated that there would be little, if any, inflow of ground water; and the seam would have to be relatively gas tight to avoid excessive gas leakage. Notwithstanding the tremendous strides that have already been made, it is my hope that the authors plan to continue their development work. Experiments on underground electrolinking and initial carbonization at Gorgas, Ala., indicate a need for improved control over the operation. Subsequent examination of the underground system at Gorgas has shown that the gasification zone did not always follow a direct path between the electrodes. Undoubtedly the control of the in-situ thermal processes can be improved by further development work. With respect to the electrocarbonization of oil shale it may be well to point out that the cost of mining oil shale is estimated to be 50c to 60c per ton. These are low mining costs as compared to coal. Thus it would appear that there is less economic incentive for applying in-situ thermal methods to oil shale than there is for applying these methods to coal. As is the case with in-situ methods for petroleum, the product from the shale having the most economic interest would be liquid oil rather than gas. The authors point out that for distances up to several hundred miles it is cheaper to transmit energy as electricity than it is to ship energy as coal. This is a very important point, and with coal shipping rates rising periodically, it could prove increasingly important in the future. I believe that the authors deserve great credit for their outstanding work on underground electrocarbonization. The knowledge resulting from their efforts is of great value to our fuels technology. James L. Elder—The experimental work conducted by the authors on the electrolinking-carbonization of carbonaceous materials in situ is of great interest. The method is of great importance in the development

Jan 1, 1955

By William J. Priestley

Much time has been devoted, by metallurgists, to the study of steel after solidification and remarkable strides have been made in the heat treatment of steel, but less knowledge is available of the thermophysical activity of the constituents of steel prior to solidification in the mold. It is known that certain elements added to steel produce marked changes in physical properties, also that other elements added to steel produce similar changes, but we have only meager knowledge as 'to. how these elements combine in steel under different conditions of solidification. It is not sufficient to know, from chemical analysis, that a certain element is present in steel. We should know how this element is in combination with the other elements and whether the combination is such as will give the greatest physical properties. Certain elements go into solid solution with the iron, while others segregate to the grain boundaries and combine with the impurities collected there. Until it is known where an alloy produces the most beneficial effect and a means is determined for controlling its physical location by altering solidification conditions, or otherwise, we will not obtain the maximum value from our alloys. When molten steel freezes, it forms a heterogeneous mass of various crystalline constituents; and as the transformation of steel from a liquid state to the solid crystallized state is a critical step, involving as great a transfer of heat as any other operation in the making of finished steel, a variation in the rate of this heat transfer will have much to do with the arrangement of the various constituents in the solid state. The object of this paper is to show some of the effects on steel caused by variations in the rate of cooling in the ingot mold, particularly as to ingotism, segregation, dendrites, and intergranular material.

Jan 1, 1924

By Frank Firmstone

In a paper read at the meeting in Cleveland, Ohio, in 1875,* I showed that as a result of changing from open-topped to close-topped furnaces at the Glendon Iron Works, there had been a decided falling off in regularity of working, which we attributed to the very different distribution of the materials in the new method of filling. Subsequent experience has, on the whole, confirmed the opinions then expressed, and in 1881 we decided to try the modification of the Langen charger, shown on the accompanying drawings, thinking by its use to approximate to the distribution obtained by dumping the barrows at six equidistant points in the circumference of the open-topped furnaces. The top of the furnace is closed by a ring-shaped " bell," as we still call it, the outside of which is cylindrical and rests by the turned lower edge on the bored seat of a " loose ring," supported by the lower part of the hopper. The inside of the bell is an inverted frustrum of a cone, the central opening in which is closed by a cylindrical plug, which is prolonged into a pipe to carry off the gas.? This center-plug is connected by rods and chains to sectors on the ends of a forked lever, to the other end of which is attached, by a wire rope, the piston-rod of the blast-cylinder used in opening the top. The rods connected to the center-plug pass loosely through the apexes of triangular frames, to the other angles of which the bell is attached; it thus being suspended by four points when the top is open. When the materials are dumped out of the barrows into the hopper, a part is thrown over the crest of the bell into the space between it

Jan 1, 1885

By AIME AIME

EVERETTE LEE DEGOLYER, past President of the Institute and Anthony F. Lucas Medalist, was presented with the John Fritz Medal at a dinner at the Wal-dorf-Astoria Hotel in New York, Jan. 14. Dr. DeGolyer is the third representative of the Institute in recent years to receive the John Fritz Medal which is awarded jointly by the four Founder Engineering Societies through a board composed of sixteen past presidents. In 1938 Paul D. Merica was given the award "for important contributions to the development of alloys for industrial uses" and in 1933 the distinction was given to D. C. Jackling "for notable industrial achievement in initiating mass production of copper from low-grade ores through application of engineering principles."

Jan 1, 1942

By Benjamin Smith Lyman

The question of the original extent of the anthracite-beds of Pennsylvania has often been raised; and even discussed with reference to the probability of their present existence under the New Red, a matter of immense practical importance. So high an authority as my revered master, J. P. Lesley, Honorary

Jan 1, 1903

By Charles E. Mann, Douglas J. Lootens, Rufino B. Bomasang

INTRODUCTION The economy of the Philippines, like that of many other developing nations, has been severely strained by the rapid escalation of imported crude oil prices over the past decade. In an effort to reduce its dependence on imported crude, significantly increased emphasis, both in the public and private sectors, is being placed on the rapid development of Philippine coal resources. This paper is designed to present an overview of the Philippine coal industry, its historical development, present status, and future potential. COAL RESOURCES AND RESERVES In 1977, a British consulting firm collated all available data on Philippine coal resources and estimated the total coals potential at about 0.9 to 1.4 billion metric tons (mt). In 1981, using more recent data the Philippine Bureau of Energy Development (BED) estimated the potential at 1.7 billion mt. The BED estimated the proven coal reserves at 257 million mt. These coal resources are scattered throughout the major islands comprising the Philippine archipelago. However, about 52 percent of the currently proven reserves are located in the tiny island of Semirara between the islands of Mindoro and Panay. About 25 percent is located in the Cagayan Valley in northeastern Luzon while 13 percent is located in Mindanao. The remaining 10 percent is scattered in the islands of Cebu, Samar, Mindoro, Negros, Polillo, Batan, and Catanduanes. The bulk of Philippine coal is sub-bituminous in rank. Some bituminous coal with coking properties has been reported in Malangas, Zamboanga del Sur in western Mindanao, and in Catanduanes, but the exact tonnages have not been accurately established. It is believed, however, to be at most 5 million tons. A little semi-anthracite coal exists in Malangas with the remaining unmined reserves estimated at a little more than one million tons. Table 1 shows the quality ranges of Philippine coal deposits.. Figure 1 shows the distribution of known Philippine coal resources PHILIPPINE COAL PRODUCTION In 1981, total coal production was 330,720 mt. Though modest by world standards, this was the highest production figure in Philippine coal mining history. This came from 25 mines, mainly small scale underground mines of capacities varying from 10 to 100 tons per day (tpd). The actual production capability was about 800,000 mt in 1981, but the producers had to scale down production to the level of local demand. Even then, some 50,000 tons of coal remained unused by year-end. The 1981 production came from the following areas: Cebu 224,751 mt (68%) Zamboanga del Sur 57,095 mt (17%) Semirara 13,222 mt (4%) Polillo 17,132 mt (5%) Cebu has always been the main source of Philippine coal production. Coal mining has been carried out in Cebu for the last 50 years, although it has been characterized by a very crude mining technology. Due to the limited size of coal deposits and complicated geology, however, Cebu's share of the total national production is expected to go down to only 10 percent by 1985. Except for Semirara's open-pit production, the balance of Philippine coal production comes from underground mines. These underground mines generally use room-and-pillar methods, except for those at Zamboanga del Sur and Polillo which use modified longwall methods patterned after those used in Taiwan. Due to the much higher mining recovery, most underground mines are now planning on switching to longwall. At Semirara, an open pit mine is now being developed for a one million ton per year capacity by 1984, and will then be the largest Philippine coal mine. While present earthmoving work is done with bulldozers, loaders, and trucks, the main coal extraction equipment will be bucket wheel excavators imported from Austria. PRESENT COAL UTILIZATION Existing coal production is sold mainly to coal- fired cement plants and power plants. The balance is sold to a sugar central, a coconut oil mill, a food processing plant, and two plants producing carbide and ferro-silicon alloys.

Jan 1, 1982

By E. S. Davenport

WHEN annealed carbon, or low-alloy, steels are suitably heated the ferrite (alpha iron solid solution) and the carbide, of which they are composed, react together to form a single solid solution of carbon (and other elements) in gamma iron (austenite). This reaction may begin only at a certain minimum temperature called the eutectoid temperature. The first ferrite and carbide thus to react together do so in definite proportions known as the eutectoid composition. With further heating the original constituent that is present in excess is dissolved in the austenite until exhausted. Whether the excess constituent be ferrite (hypoeutectoid steels) or carbide (hypereutectoid steels) the procedure is much the same, and upon slow cooling the homogeneous austenite expels the excess of either (proeutectoid ferrite or carbide) until the eutectoid composition is reached. Thus the reaction upon heating is strictly reversed upon cooling and accordingly an equilibrium diagram of this process may be constructed. Such an equilibrium diagram concerns itself only with the tempera¬tures involved and with the proportions and compositions of the phases developed under conditions that suffice to permit equilibrium. Specifically it has no concern for the type or mode of distribution of these constituents nor with any extra-equilibrium conditions such as undercooling, which is almost universally encountered in metals. Actually, however, of great importance is the sluggishness toward equilibration caused by the not inconsiderable time involved in diffusion. Thus instead of the theoretical transformation point AE, we find for a certain rate of heating or cooling the use of the designations Ar and Ac (transformation temperature found on cooling and upon heating). These figures obviously have no particular meaning except as measured and expressed for a definite heating or cooling rate, and represent the apparent temperature displacement caused by an inadequate time allowance. In this paper are presented the results of a study of the time required for' the transformation of austenite to ferrite and carbide at a variety of temperatures and also of the time required for the reaction austenite ?martensite at the temperatures at which this reaction occurs instead of

Jan 1, 1930

By Frank Fahrenwald

I. INTRODUCTORY METALLURGICAL research has discovered many an alloy possessing properties not combined in any single metal, and progress still consists chiefly in the investigation and utilization of alloys. In the case of iron, the demands of automobiles, high-speed machines and high-duty engines have led to the production of special iron alloys which will meet any reasonable specifications in that field. In like manner, the bronzes, brasses and other alloys of copper have been brought to remarkable perfection, and for nearly every industrial purpose some alloy has been found more suitable than the pure metal. Less complete success has attended the attempt to find substitutes for gold, platinum, and the other precious metals. Indeed, it is not likely that a material can be produced which will possess all the properties of any one of them; yet it is reasonable to hope that, for any given use, the properties required may, be found in some less expensive material. Thus, in incandescent electric lamps, the wire passing through the thick glass neck of the bulb was, until recently, almost universally made of platinum, for the single reason that no other known material, suitable as a conductor, had the same coefficient of expansion as glass. But a comparatively recent investigation of the iron-nickel series' has shown that alloys of those metals may be produced, the coefficient of expansion of which can be accurately controlled between that of iron or nickel and zero. Thus, in that particular industry, a substitute for platinum has been found. According to statistical reports, not only considerable quantities of gold and iridium, but also more than one-third of the annual supply of platinum, are used (and, in the nature of the case, irrevocably lost) by dentists. Platinum is thus employed in several forms. As a thin foil, it serves various purposes for which its high melting point, pliability, chemical resistance, and other properties-including the ease with which

Jan 1, 1916

THE man who forgot to mail the letters his wife gave him was for once justified at Tulsa, for envelopes, scratch paper and tablecloths were all in demand and through the two days of the meeting of the Petroleum Division, pencils were busy everywhere sketching out diagrams, drawing curves, figuring, or just taking notes. Those attending took the serious papers seriously, and discussion was wide-ranging but pointed. Despite the highly technical character of the papers presented, the chairmen had never to call for discussion; it was only necessary to say the paper was open for it. Both days the meetings lasted until after five in the afternoon, and it was enthusiastically voted to advance the meeting hour on Friday, in order to give more time. In all, ten papers, abstracts of which appeared in MINING AND METALLURGY for October, and copies of all but two of which were available in print, were presented in the two days, and no more could have been handled to advantage in that time. All but one of these dealt with problems of production engineering. That, the opening paper, was a general review of demand, supply and price in 1928, by Campbell Osborn, in which he argued for the price control of production and showed how the economic conditions determined development. J. Elmer Thomas presented a carefully prepared review of the same data, but came to somewhat different conclusions as to trend, and J. E. Pogue pointed out that in recent years it has been the manufacturing rather than the producing industries that have been notably profitable. These and other discussions were too long to be reported here, but will be printed in full later.

Jan 1, 1928

By Walter Knox, Charles H. Sawyer

All of the coals commonly used in domestic bituminous stokers form coke, and satisfactory operation depends upon the fact that the coke formed is so weakly bound together that it breaks readily in the normal operation of the stoker and automatically maintains a good fuel bed. Some coals, because of their tendency to form solid, blocky coke, are practically excluded from use in small domestic stokers as now built. Other coals, some among the best stoker coals available, can form this troublesome coke under certain conditions. Many contradictory methods have been offered as cures for coke formation. Generally the procedure has been to try various adjustments until a combination was found that seemed to give better results. Such random methods of treatment have not provided any reliable information as to causes. The present paper covers a comprehensive test program undertaken by the Koppers Company's Stoker Coal Research Laboratory at Kearny, N. J. The program had two main objectives; first, to discover what factors affected coke formation, and second; to define corrective steps that could be applied in stoker service work. Conclusions and Results i. The design of the stoker outweighs in importance all other factors capable of improving coke formation. 2. Insufficient air supply aggravates the formation of large blocky coke, although raising the air above 30 to 40 per cent excess (as determined during steady running) does not further improve the character of the coke formed and only reduces its accumulation at the expense of efficiency, increased fly ash, poorer clinker-ing, and other disadvantages. 3. Increasing the coal feed results in a somewhat more friable coke structure and is recommended for persistently troublesome jobs. 4. Increasing over-fire draft improves the character of the coke formed and reduces troublesome accumulations by accelerating off-period burning, although at some expense in efficiency and some increase in fly-ash accumulation. 5. Coke structure was not substantially improved by blocking some of 'the retort tuyeres, although the blocking of tuyeres at the feed-screw end of a rectangular retort did lead to somewhat improved performance, possibly because of considerably better distribution of coke in the fuel bed. 6. With the equipment tested no difference was shown between installation of the same stoker in a steam boiler and a warm-air furnace, or between a sand-filled and a ventilated type of hearth. 7. The following design features had no noticeable effect on coke formation: a. Presence or absence of coal-tube air as provided by many manufacturers to eliminate smoke-back. B. Presence or absence of a flap damper ill the air duct to minimize off-period burning. c. Continuous or intermittent (ratchet and pawl driven) movement of fuel feed screw.

Jan 1, 1944

By Charles H. Sawyer, Walter Knox

All of the coals commonly used in domestic bituminous stokers form coke, and satisfactory operation depends upon the fact that the coke formed is so weakly bound together that it breaks readily in the normal operation of the stoker and automatically maintains a good fuel bed. Some coals, because of their tendency to form solid, blocky coke, are practically excluded from use in small domestic stokers as now built. Other coals, some among the best stoker coals available, can form this troublesome coke under certain conditions. Many contradictory methods have been offered as cures for coke formation. Generally the procedure has been to try various adjustments until a combination was found that seemed to give better results. Such random methods of treatment have not provided any reliable information as to causes. The present paper covers a comprehensive test program undertaken by the Koppers Company's Stoker Coal Research Laboratory at Kearny, N. J. The program had two main objectives; first, to discover what factors affected coke formation, and second; to define corrective steps that could be applied in stoker service work. Conclusions and Results i. The design of the stoker outweighs in importance all other factors capable of improving coke formation. 2. Insufficient air supply aggravates the formation of large blocky coke, although raising the air above 30 to 40 per cent excess (as determined during steady running) does not further improve the character of the coke formed and only reduces its accumulation at the expense of efficiency, increased fly ash, poorer clinker-ing, and other disadvantages. 3. Increasing the coal feed results in a somewhat more friable coke structure and is recommended for persistently troublesome jobs. 4. Increasing over-fire draft improves the character of the coke formed and reduces troublesome accumulations by accelerating off-period burning, although at some expense in efficiency and some increase in fly-ash accumulation. 5. Coke structure was not substantially improved by blocking some of 'the retort tuyeres, although the blocking of tuyeres at the feed-screw end of a rectangular retort did lead to somewhat improved performance, possibly because of considerably better distribution of coke in the fuel bed. 6. With the equipment tested no difference was shown between installation of the same stoker in a steam boiler and a warm-air furnace, or between a sand-filled and a ventilated type of hearth. 7. The following design features had no noticeable effect on coke formation: a. Presence or absence of coal-tube air as provided by many manufacturers to eliminate smoke-back. B. Presence or absence of a flap damper ill the air duct to minimize off-period burning. c. Continuous or intermittent (ratchet and pawl driven) movement of fuel feed screw.

Jan 1, 1944

By J. Parke Channing

IT, HAS been my privilege to be Chairman of Engineering Council for very nearly three years, during which time Mr. A. D. Flinn, the. Secretary, and myself, have seen the organization develop until it is functioning smoothly and accomplishing what it can with the money at its disposal. The earliest attempt at what may be called an Engi¬neering Council, of which. I have any knowledge, was made six or seven years ago when the four Founder Societies each appointed two men, who occasionally met to discuss matters submitted to them which were of importance to, the, profession as a whole. I was one of the representatives of the American Institute of Mining Engineers.

Jan 1, 1920

By Joseph J. Yancik

In Moscow, the delegation received a briefing on the Soviet coal industry from First Deputy Minister Vladimir Fedanov. A similar briefing was given to us on the Donets coal basin by Deputy Minister S. Saratikyanz of the Ukrainian Coal Ministry. Lengthy technical discussions were held with the mines staff and research personnel at the institutes we visited. In addition, we had detailed discussions with key staff members of two combinats; Donetskugol and Tulaugol. In all these meetings, principal topics were matters of safety related to hazards associated with face mechanization, coal transport, methane gas control measures, gas outbursts, coal and rock outbursts, fire fighting and control, explosion suppression and control measures, and other related hazard factors. There was also much discussion on miner training, miners' attitudes toward safety and accident prevention practices, and preparation and enforcement of safety rules and regulations. It would be helpful to briefly review Soviet coal production statistics for comparison purposes with the U.S., and for the purpose of referencing some of the delegation findings mentioned in this report. For an excellent, comprehensive picture of Soviet coal production and other related fuel statistics, the reader is referred to Strishkov's, et d. report.1 Strishkov's estimates agree with the numbers given us by Coal Ministry officials except in clean coal tonnage. The figures of 604 million mt of clean coal out of a total production of 655 tons raw coal in 1972 is much higher than Strishkov's estimate of 375 million mt clean coal.

Jan 7, 1974

By C. Richard Tinsley

Like most minerals, coal is inherently a demand-limited commodity. The very sedimentary nature of its occurrence implies greater availability potential than demand. But this situation is overridden by economics among fuels, between coals, and within coal blends. Such considerations make coal forecasting a very hazardous profession indeed. THERMAL COAL If one thought that the lead times involved with a mining project were very long, one has obviously not been exposed to the planning process in the electric generation business - a process seriously confounded by shifts in load growth, environmental pressures, capital intensity, security of fuel sourcing, inter-fuel economics, and so on. But as a general rule, the near-term forecasts for thermal coal can reliably be based on a bottom-up, plant-by-plant analysis. Cement plant conversions can also be reasonably estimated next in order of reliability, although they have a much wider spectrum of coal qualities and fuel sources to choose from with a notably higher tolerance for sulfur and ash. Finally, industrial demand can be assembled from the estimates for conversions by pulp/paper plants, chemical plants, etc. The industrial sector is harder to estimate, since it may involve small boilers or dual-fired units. Assessing demand in the Pacific Rim is relatively a straightforward process in the near term because the major importing countries are all located on the Asian continent with either negligible or very minor (yet stable) indigenous coal production, (itself often operated on a subsidized basis). Furthermore, all imports are seaborne. These major importers are Japan, Korea, Taiwan, and Hong Kong with Thailand, Singapore, and Malaysia up-and-coming consumers. The suppliers to this market all have substantial reserves to back up decades of exports to these countries. Australia, the US, Canada, South Africa, China, and the USSR dominate the supply side. The second oil-shock of 1979/1980 has convinced the importers that reliance on oil can be expensive and eminently interruptible. Thus, they are determined to diversify away from oil' to nuclear and coal for generating electricity and for coal for other purposes where possible. This trend is seen to continue even in the face of the oil glut worldwide and oil-price reductions in early 1982. But the importers are also convinced that reliance on one coal source and, in particular, one infrastructure route for the coal chain from mine to consumer can be equally expensive and interruptible. Strikes in the US and Australia; excessive demurrage at certain ports; relegation of coal to a lower priority on multiple-use railroads in the USSR and China; and concern over escalation on high-infrastructure or high-freight coal chains are among the risks worrying the importers. As a consequence, Pacific Rim thermal coal purchases are being allocated among supplier nations, between ports, and within each country. An example of Japan's shift away from Australia and toward the US and Canada is shown in the estimates in Table 1. But the confidence of the import estimates deteriorates sharply beyond the plant conversion timetables and construction schedules in the near term. If part of the second generation of coal-fired power plants can handle lower-energy coals, the field of suppliers could widen to accept sizeable tonnages from Alaska, Wyoming, Alberta, or New Zealand resources. These supply sources generally have some infrastructure or freight advantage to compensate for their lower quality and to compete on a delivered energy-unit basis. These also offer diversification in sourcing. And the possibility of coal liquefaction in Japan further widens the sourcing network. A great number of Pacific Rim coal forecasts have been generated, especially for Japanese thermal-coal imports which are expected to grow strongly in the 1980's. Since the Japanese themselves have not yet settled their energy policy, the exact numbers are hard to call. Nevertheless, at 50 million tonnes of imports in 1990, Japan would consume 50-60% of the total Asian thermal coal imports as shown on Tables 2 and 6. The next most important consumers are the "island" nations of Korea, Taiwan, and Hong Kong (see Tables 3-5). All three are embarking on power plant developments usually with captive unloading facilities, capable of accepting more than 100,000-dwt vessels. Korea, with no-indigenous bituminous coal, is not especially enamoured with US coals, which are deemed too heavily loaded by freight and infrastructure costs -- up to 70% of the delivered price. Thermal coal contracts are presently split to Australia (70%) and to Canada (30%). Korea Electric Power Co. is already considering second-generation boilers capable of burning lower-quality coals than the present standard. Korea does burn domestic anthracite.

Jan 1, 1982

I would like to congratulate the authors on an interesting paper and, in particular, on their justification of the use of superposition in treating gas wells. They state, however, that no theory has previously been developed lor treating the variable rate drawdown case. In a paper published a few years ago by my colleagues and myself, a method is described which allows a constant rate drawdown curve to be derived for any well. regardless of real rate variations. This method has the great advantage that it is not necessary to make any assumptions regarding the form or uniformity of the reservoir, and the derivation suggested by the present authors is simply an idealized case of our more general treatment. In the light of several years' experience in the derivation of constant rate drawdown curves: I would like to point out that the method proposed by Odeh and Jones may lead to confusing answers, particularly if applied over an appreciable time interval. The reason is that, if pressures are measured when a well is flowing, non-linearities in plots like Figs. 1 and 2 can arise due to either (1) changes in the skin factor with time and/or flow rate, or (2) an inhomogeneous reservoir. Separation of these two effects is only possible if some of the pressures used in the analysis are measured when the well flow rate is 0 or, in other words. during brief shut-in periods. REFERENCES 1. Arthur, K. B.. Metunomski, Z. G. and Ruche, Ms "Intetet ct methode d'utilisa tion des mesures de pression [)our Petude des gisemonts" Revue de T'I.F.P. (Nov., 1962) XVII, 1299. 2. Thomere, R. and Arthur, K. R.: "Analysis of the Pressure Bet~avior of a Production Well Subject to Interterence and Its Application to Reservoir Models", Paper SPE 1189 presented at SPE :Amund Fall Mecting Ireld in Denwer, Colo. (Oct. 3-6, 1965).

Jan 1, 1966

By A. C. Butterworth

M OST operators of open-pit mines in the Lake Superior iron ore district are quite familiar with the use of fuel oil in the heavy-duty Diesel engines commonly used in truck-haulage service but some operators, including my own company, Pickands Mather, have had butane-engine trucks in service for several years, and less is known of their operation. One of the first installations of trucks for iron-ore haulage was in 1939 at a deep open-pit mine on the Cuyuna Range. These superseded standard-gauge steam haulage. Trucks then obtainable were equipped with 150-hp Diesel engines, and the speed of these units on an 8 % grade would have been so slow, considering the depth of the pit, that plans for an all-truck haul out of the pit were rejected. About this time one of the engine manufacturers brought out an auto-

Jan 1, 1948

By F. Ernest Brackett

Much new data on the flow of gases have been discovered by recent experiments by the United States Bureau of Mines and others. Although additional investigation is still desirable, the information now collected seems sufficient to attempt a tentative coördination of the friction factors. This study is confined entirely to fluid friction when the density throughout the duct is so nearly constant that it may be so considered. In the subsequent discussion the following notation is used: v = mean velocity of fluid in duct, feet per second. v' = mean velocity of fluid in duct, meters per second. R = hydraulic radius of duct, feet. R' = hydraulic radius of duct, meters. S = the hydraulic slope. P = pressure absorbed by friction, pounds per square foot. p = pressure absorbed by friction, pounds per square inch. p' = pressure absorbed by friction, kilograms per square centimeter. A = sectional area of duct, square feet. O = perimeter of duct, feet. L = total length of duct, feet. L' = total length of duct, meters. d = diameter of a cylindrical duct, inches. w = density of the fluid, pounda per cubic foot. g = specific gravity of the fluid compared with water = w % 62.4. C, k and B, coefficients for formulas using English measures. C' = metric coefficient, v' = C'R'S. n = coefficient of roughness for English or metric units. The basic formula for the flow of all fluids at constant density appears in the three following forms, which may be denominated: (a) The slope formula, v = CRS (b) The ventilation formula, " n = (c) The pipe formula, C is Kutter's coefficient, which is extensively applied to the flow of water in ducts and channels of all kinds; E is Atkinson's coefficient, used principally with air in ventilation problems; B is a coefficient conveniently adapted to studying the flow of water, gases and vapors in pipes. 312

Jan 1, 1927

By J. K. Elliott, P. H. Kelly

Many engineering functions such as surface metering work and laboratory compressibility check points involve the use of liquid densities of light hydrocarbon mixtures at various pressures and temperatures. However, at the present time, no simple reliable method exists for determining density variation, particularly if the composition of the liquid is unknown. Consequently, a study was undertaken to develop and present a simple and accurate method of predicting density variation of a light hydrocarbon liquid with pressure and temperature, knowing only the density of the liquid at some condition. The experimental liquid compressibility data from API Project 37 by Sage and Lacey' have been considered to be accurate within 0.5 per cent and cover a wide range of pressure (14.7 to 10,000 psia), temperature (100" to 400°F) and molecular weight (up to 150). From these data, a set of liquid density curves, which relate density to pressure, temperature and molecular weight, was developed. These curves make it possible to predict density variation with pressure and temperature. Compared to extensive laboratory compressibility data on a complex, light hydrocarbon liquid, the use of the liquid density curves resulted in an average error of less than 0.5 per cent. Based on the results of this analysis, it is concluded that the set of liquid density curves developed from the data of Sage and Lacey provides an accurate and simple method for predicting the density variation of light hydrocarbon liquids when the density at some condition is known. These curves should be very helpful in many engineering calculations, particularly in the surface metering of light hydrocarbon liquids. INTRODUCTION Many situations arise in field and engineering laboratory work, such as reservoir engineering studies, check of experimentally determined laboratory data and orifice flow-meter formulas, where liquid density factors at various pressure-temperature conditions are required. Also, the need for accurate light hydrocarbon liquid information has become more important with the advent of miscible-type displacements for secondary recovery purposes in oilfield operations. Several reliable methods are available1 - "or determining the density of liquid hydrocarbons if the composition of the liquid is known. However, there is a definite lack of methods for accurately determining the variation of density when the composition of the liquid is unknown. The purpose of this study is to review the various methods for determining hydrocarbon liquid densities and to develop a simple and reliable method of determining variation in density of light hydrocarbon liquids with pressure and temperature when the compositio~n of the liquid is unknown. METHODS FOR DETERMINING DENSITY OF LIQUIDS OF KNOWN COMPOSITION Sage, Lacey and Hicks' have proposed a method to predict the density of light liquid hydrocarbons by using partial molal volumes. Data are available on experimentally developed partial liquid volumes of hydrocarbons over a rather limited range of temperature, pressure and composition. The partial mold volume method has proved satisfactory for determining the density of some hydrocarbon liquids when the composition is known. Within the range covered in the Sage, Lacey and Hicks1 data, the results agree within about 3 per cent of the experimental values. Hanson mentions the limitation of this method to a composition range of approximately 10 per cent by weight of methane, which will not allow this correction to cover most low molecular weight-light hydrocarbon liquids. Standing and Katz2 studied data on light hydrocarbon-liquid systems containing methane and ethane at high temperature and pressure and have presented a method for determining liquid densities, assuming additive volumes for all components less volatile than ethane and using apparent densities for methane and ethane. The compressibility and thermal-expansion curves used by Standing are based on assumptions that compressibility of a hydrocarbon liquid at temperatures below 300°F is a function of the liquid density at 60°F and that thermal expansion of the liquid is affected little by pressure. The information required to use this technique with an example problem is furnished by Standing.' Hanson eports an average error of - 0.5 per cent using the method of apparent densities in calculating liquid densities of several volatile hydrocarbon mixtures. However, as implied, the apparent density method is not applicable for liquid density calculations when the composition of the liquid is unknown. Watson- as presented a method

C. Edward Stafford, Chester, Pa.:—Doring all my business life, I have been engaged in the manufacture of Bessemer and open-hearth steels, but, during my long connection with the Shoenberger Steel Co. of Pittsburg, I had some experience in the manufacture of high-grade puddled iron for horseshoes, and in making, by Dr. Otto Wuth's process, extremely pure, low-phosphorus puddled blooms (analyzing from 0.005 to 0.01 per cent. of phosphorus and sulphur), which were melted with low-phosphorus pig-iron in acid open-hearth furnaces, to make extra locomotive fire-box steel. I have also seen the Danks puddlers in operation at different times and places, notably where they were most successful, at the Otis Steel Works, Cleveland, Ohio; then under the management of our friend, Mr. S. T. Wellman. These Danks blooms were made solely for open-hearth melting-stock, to which they were well adapted. (The unavoidable presence of bits of ore-fix imbedded in the mass of the metal always prevents the profitable manufacture of merchant iron from Danks' blooms.) With the experience just described, I was to some degree in position to value fairly the means, methods and results of Mr. Roe's mechanical puddling from the metallurgical or technical and economic points of view, when given an opportunity by Mr. Roe to see his puddling-furnace or machine in operation in Pottstown, Pa. Briefly, the furnace, with water-cooled bottom, is rectangular in plan, about 20 by 8 ft. in the clear, suspended by trunnions at the middle of the long sides, at a height of 17 or 18 ft. above the general level. The oscillation (65" each way from the vertical) is accomplished by geared segments (attached to the downward-projecting side or trunnion-plates) with which engage pinions driven by a reversing engine. The whole section

Jan 1, 1906

By C. A. Queener, W. L. Mitchell

In recent years bismuth telluride has received considerable attention, primarily due to its value as a thermoelectric material. Since there seems to be little dependence of thermoelectric effect upon crystal orientation1 many of those who have previously worked with this material have been unconcerned with knowing its crystallographic angles to any degree of accuracy. However, when one studies deformation modes, lattice stresses, or the aniso-tropy of mechanical properties of a material, knowledge of the interplanar angles and their relationships as depicted in a stereographic projection becomes essential. Lange2 originally published crystallographic data which described the structure of bismuth telluride as rhombohedral with the space group A more recent work by Francombe3 presented data which corroborated and refined the original findings of Lange. In addition, Francombe established that there is no coexistence of rhombohedral and hexagonal lattices in bismuth telluride as was suggested by Vasenin and Konovalov,4 and that the structure can be treated as a pseu do hexagonal structure with an axial ratio, c/a, of 6.95 for convenience of presentation and study. The interplanar angles and standard projections for several unalloyed hexagonal metals have been previously published,5-9 but the present work appears to be unique in that it presents data for a rhombohedral compound in pseudohexagonal form. As a pseudohexagonal structure, this material has an extremely large axial ratio as compared to the usual range of approximately 1.5 to 1.9 for the hexagonal metals. Since the interplanar angles are a function only of c/a, the angular relations between various planes for Bi,Te3 will be grossly different

Jan 1, 1965