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By CARLE R. HAYWARDC

BEFORE discussing this subject it is necessary to define somewhat the meaning of the tern metallurgical.. When I was a student at M. I. T. ore-dressing was not thought of as metallurgy in any sense of the word, but it was considered as more closely allied to mining, enabling the miner to market an otherwise unmarketable product, or at least to market it to better advantage. Progress in ore-dressing has gradually allied it more closely with smelting, for at present the raw material received by the smelter is predominantly concentrates and smelting practice has been profoundly affected by the products of the concentrating mill. It is not surprising therefore that in many schools ore-dressing is frankly considered as metallurgy and although there may be some dissenting opinions it will be considered as such in this discussion. Twenty-five years ago at M. I. T. metallography was taught in a few optional lectures. This subject has developed rapidly and been expanded into the new and increasingly important field of physical metallurgy. To many metallurgists the -term metallurgy means only physical metallurgy. They know little or nothing about smelting and leaching and even less about ore-dressing. Having then broadened the scope of the term metal¬lurgy to cover ore-dressing, smelting, leaching and phys-

Jan 1, 1930

By J. W. Eckerd

The crushing of chestnut-size (1-5/8 by 13/16 inch) Pennsylvania anthracite in four commercial crushers (impact) jaw) hammer-mill) and gyratory types) was studied by the Bureau of Mines to determine which could produce the largest proportions of buckwheat Nos. 1 and 2 sizes (9/16 by 3/16 inch). Single pass dry and wet crushing techniques and the effect of stage crushing were evaluated. Calculations were made to show the effect of closed-circuit reduction on production rates and yield of the various sizes. The data show that the gyratory crushers produced the greatest percentage of the desired sizes. A ring-type hammer mill produced the greatest tonnage of buckwheat No.1 and rice (14.9 tons per hr.) during dry grinding tests) but the yield of these sizes was only about 55 percent) as compared with 62 to 70 percent for the gyratory crushers. The impact and jaw crushers produced the smallest amount of buckwheat and rice and the largest quantity of oversize material.

Jan 1, 1960

By Mathew Cook

Technological developments in Distributed Fiber Optic Sensing and improvements in both hardware and software have allowed fiber optic sensing systems to be deployed in a variety of applications such as pipeline leak detection, perimeter security monitoring, and power cable real time thermal rating. Recently, there has been a larger adoption of monitoring of conveyor belts in so called Conveyor Health Monitiring Systems (CHMS) within the mining and bulk material handling industries to identify idler conditions on an ongoing basis. Several attempts have been made to institute sensing capabilities into conveyors with mixed success. However, recent breakthroughs in modeling, installation methodology, and technology, as well as increased understanding of application and industry requirements, have allowed the technology to be deployed at both experimental and commercial scales. This paper summarizes the application conditions and requirements, design considerations, methodologies used, the outcomes achieved, the logistical and field considerations, and the future possibilities of the use of this technology in CHMS using Distributed Fiber Optic Sensing.

Feb 22, 2026

By S. C. Maji, U. S. Chattopadyay, S. Chaudhuri, T. Gouri Charan

India is devoid of coking coal resources, which is a vital raw material for coke making. As a result it has to import about 80% coking coal for steel making. Indian National Steel Policy, 2017 has envisaged crude steel production around 300 million tonnes Mt) by the year 2030-31 and forecasts coking coal demand of 161 Mtpa (million tonnes per annum). One way of improving the indigenous resources is to study the performance of existing washeries and to improve the clean coal recovery by adopting suitable technology. A study was carried out, mainly to focus on the fine coal circuit of an existing coking coal washery, to generate the desired quality of clean coal. The operating coking coal washery being studied is presently feeding coal from nine different sources with varying feed ash contents. The coal fines varied in ash content ranging from 19.5% - 43.6%. For treating the coal fines, the washery has operated a spiral for the past few years. Performance studies were carried out, and it was found that the spiral is not efficient in recovering the cleans. Detailed investigations were carried out on the coal fines using flotation techniques, and it was found that to achieve a low ash clean coal, the froth flotation is a much better beneficiation option than a spiral, The studies showed that the recovery of clean coal through a spiral is 67.7% at ash content of 27.0%, while flotation tests showed a recovery of 68.1% at 16.5% ash content. Keywords: Coking coal washery, near gravity material, spiral washer, froth flotation

Jan 1, 2020

By M. Ramulu, A. K. Chakraborty, P. B. Sahu, C. Bandopadhyay, P. B. Choudhury

Human response to blast induced vibration and air overpressure is an unsolved problem that accompanies excavation process in mining. Pre-assessment and understanding of annoyance due to production blasting is probably one of the most important aspects of a successful mining operation. Complaints arising due to unoptimised blasts lead to various critical situations that hamper production. Inspite, this important aspect has been covered by a limited number of researchers in the world and probably least in Indian context. Human response is a complex phenomenon and the sensitivity of individual also vary from person to person depending on various factors like age, sex, literacy, health and exposure to mining. With ever increasing demand of minerals, opencast mines are expected to approach habitats and thus mine management may witness increased response to blasting. Many developed countries have their own guidelines based on scientific analysis, addressing such environmental problems, where as there are a few studies available in India. This study introspects above phenomenon in tune with mining requirements by analysing direct human response. This paper is based on a case study regarding the human response to blast induced hazards in a Manganese mine situated in central India. Advanced techniques of Critical Path Method and Multiple Response Analyses have been used to unearth important inferences on the response of different crosssections of population residing about the mine to blast induced noise, ground vibration and air overpressure. Various inferences drawn may provide guidelines to the planners, environment or safety departments and blasting official for safe and environment friendly blast design.

Jan 1, 2004

By Pingchao Ke

A crystalline polyferric sulfate (PFS) adsorbent was synthesized by oxidizing and precipitating ferrous ions under atmospheric conditions. The morphology, structure, composition and specific surface area (SSA) and adsorptive efficacy to As (III) of the adsorbent were characterized by SEM/EDS and TEM images, XRD patterns, FT-IR spectra, BET SSA analyses and adsorption experiments. The adsorbent presents as morphology of near-spherical aggregate and good crystallinity. A small amount of goethite co-precipitated with PFS in the case of the initial ferrous concentration of 1 mol/L and increased the SSA of the aggregates. The absorbent with co-precipitation of goethite showed good adsorption to As(III) and good filtering performance in the high As(III)-content solution of 10–100 mg/L under acidic, neutral and alkaline conditions (pH 2.09–9.01), and its maximal adsorption capacity and adsorption efficiency were 7911 μg/g and 96% separately. After Adsorption, the stability of the absorbents adsorbing As(III) were evaluated by TCLP tests, and the results indicated that the absorbents adsorbing As(III) were extremely stable, and the concentration of arsenic in all leaching solutions were less than 0.01 mg/L.

By Mark I. Copeland

The formation of A1203 dispersoids 0,14 and less in size in dilute iron-aluminum alloys by internal oxidation in wet hydrogen and dispersion strengthening of iron by application of the technique to iron powder were found to be feasible by the Bureau of Mines. In flowing H2-1.5 H20 gas, A1203 dispersoids 0.1w and less in size formed (at 650° to 750° C) in Fe-l and 2 Al sheet material but not in Fe-3 or 4 Al alloys. With higher temperatures and/or higher H2O/H2 volume-ratio gases, A1203 and FeA1204 dispersoids >0.14 in size formed in all the sheet materials- Minus 100-mesh Fe 2 Al powders were internally oxidized under conditions that promoted formation of fine A1203 particles in sheet material, and then the oxidized powders were hydrogen reduced, sintered, extruded, and evaluated. During internal oxidation, fine A1203 dispersoids formed within the powder grains, and coarse FeA1204 particles formed on the powder surfaces and grain boundaries. The FeA1204 content was essentially eliminated during sintering by reacting with the unoxidized aluminum that remained in the center of the larger internally oxidized powders. The tensile strength at 800° C depended upon the aluminum-oxygen weight ratio of these elements in the extrusions and reached a maximum of 17,000 psi. The stress-rupture strengths at 800° C of the better alloys were comparable with those of type 310 stainless steel.

Jan 1, 1972

By D. E. Banks, J. K. H. Ma, Y. Rojanasakul, J. Y. C. Ma, C. J. Malanga

There is evidence to suggest that cell injury induced in alveolar macrophages (AM) following phagocytic activation by silica particles may be mediated through changes in intracellular free calcium [Ca 2+}. However, the mechanism of silicainduced cytotoxicity relative to [Ca2+], overloading is not yet clear. To provide a better insight into this mechanism, isolated rat AMs were exposed to varying concentrations of crystalline silica (particle size< 5 µm in diameter) and the fluctuation in their [Ca2+]; and cell integrity were quantitatively monitored with the fluorescent calcium probe, Fura-2 AM, and the membrane integrity indicator, propidium iodide (Pl). Results from this study indicate that silica can rapidly increase [Ca2+]; in a dose-dependent manner with a characteristic transient calcium rise at low doses (<0.1 mg/ml) and an elevated and sustained rise at high doses (>0.1 mg/ml). Depletion of extracellular calcium [Ca 2+]0 markedly inhibited the [Ca2+]; rise (˜90%), suggesting that Ca2+ influx from extracellular source is a major mechanism for silica-induced [Ca2+]; rise. When used at low doses but sufficient to cause a transient [Ca2+]; rise, silica did not cause significant increase in cellular Pl uptake during the time of study, suggesting the presevation of membrane integrity of AMs under these conditions. At high doses of silica, however, a marked increase in Pl nuclear fluorescence was observed. Depletion of [Ca 2+] 0 greatly inhibited cellular Pl uptake, induced by 0. 1 mg/ml or higher doses of silica. This suggests that Ca 2 + influx, as a result of silica activation, is associated with cell injury. Indeed, our results further demonstrated that the low dose effect of silica on Ca 2+ influx is inhibited by the Ca2+ channel blocker nifedipine. At high doses of silica (>0.1 mg/ml), cell injury was not prevented by nifedipine or extracellular Ca2+ depletion, suggesting that other cytotoxic mechanisms, i.e., nonspecific membrane damage due to lipid peroxidation, are also responsible for the silica-induced cell injury. Silica had no significant effect on cellular ATP content during the time course of the study, indicating that the observed silicainduced (Ca2 ... ); rise was not due to the impairment of Ca2 + -ATPase pumps, which restricts Ca2+ efflux. Pretreatment of the cells with cytochalasin B to block phagocytosis failed to prevent the effect of silica on [Ca2+]; rise. Taken together, these results suggest that the elevation of [Ca2+]; caused by silica is due mainly to Ca2+ influx through plasma membrane Ca2+,channels and nonspecific membrane damage (at high doses). Neither ATP depletion nor Ca2+ leakage during phagocytosis was attributed to the silica-induced [Ca2+]; rise.

Nov 1, 1995

By S. Wood

"Plastic Filled Valley (PFV) wire rope represents a significant development over the design of conventional wire rope. A sealing thermoplastic is impregnated under controlled conditions of temperature and pressure into a conventional lubricated wire rope to produce a lattice of plastic which surrounds and separates the strands from each other and from the core. Metal-to-metal contact is thereby alleviated and the lubricant is sealed in. The wear resistance, rope breaking load, fatigue resistance and crushing resistance are all increased. The result is a rope which offers exceptional service life.Laboratory tests carried out in Canada and at the University of Stuttgart, in West Germany, confirm the increase in fatigue life. The field trials conducted so far have indicated that the results obtained in the laboratory can be duplicated in the field.IntroductionIn times of double -digit inflation, the consideration given to operating costs throughout industry commands considerable attention. The same can be said of the mining industry. A set of large-diameter wire ropes used on the huge draglines in strip mining can cost in excess of $100,000. Because a machine may use three sets of rope s each year, it is clear that the costs of wire rope can contribute a considerable percentage to any operating budget. As wire rope is a product which is used extensively throughout the mining industry, it would appear timely to turn our attention to any ""Method of Extending Wire Rope Service Life"" in order that wire rope life can be optimized and wire rope costs can be minimized."

Jan 1, 1982

By Jeff Starchuck, Harald Kullmann

"In 2005, an inspection showed that the Deception Bay Wharf in the Canadian Arctic was at the end of its service life. Although Deception Bay is closed with landfast ice up to 5 ft thick, shipping operations continue year-round, with additional voyages in the summer open-water season to supplement mine supplies. The rehabilitation scheme that allowed minimal interruptions to shipping involved concrete caissons cast on barges and an ingenious placing system.WorleyParsons Westmar of Vancouver, B.C., performed the inspection under contract to the owner, Xstrata Nickel, Montreal, Quebec. The wharf, on the coast of the Nunavik region of Quebec, was originally constructed in 1971 for an asbestos mine, and is now used to support Xstrata’s Raglan nickel mine, importing fuel for p o w e r g e n e r a t i o n a n d general mine supplies, and exporting nickel concentrate to smelters in the south. Emergency repairs were essential to allow operations to continue at the site, while the parties considered permanent rehabilitation options and secured funding. The repairs were done in the openwater seasons, and included reinforcing the failed interlocks above water level with steel patch plates and injection grouting of the cell fill below the port crane in 2005. In 2006, workers installed a circumferential belting system below water level.Westmar held critical planning sessions with the mine operation personnel to find ways to stretch the limits of the mine supplies and nickel storage facilities. In the end, the parties agreed to shut down construction activities four times during the ice-free season to allow access to the dock site.Westmar developed a plan that allowed mine operations to continue during construction, and Xstrata approved the plan and budget in September 2006, for execution in 2007. Rapid construction was essential. To accommodate the short construction season and maintain minimum levels of service for the mine, the work was radically different from conventional Arctic deep-sea port construction. Like the original Deception Bay Wharf, construction practice was to use steel sheet pile circular cells with the consequential heavy support services for the labour force. Construction duration was typically two seasons. The plan for Deception Bay was executable in one season based on a concrete caisson structure. Only a modest amount of schedule float was needed."

Jan 1, 2009

By Ümit Yasar Onder, Tevfik Prof. Dr. Güyagüler

This paper describes the results of an investigation done to determine thermal properties and heat emission of coal measure rocks in Karadon district of Zonguldak Coal Colliery. In Karadon District, depth of working level is about -600 m where the heat problem arises. In the near future, workings will be at deeper levels and working conditions will be more difficult due to high heat emission. At the beginning of the paper the importance of wall rock heat emission in underground mine have been explained and then the amount of heat emission to the ventilating air has been calculated. It has been found out that the strata is the main source of heat in the mine. Therefore, geothermal gradient of the region has also been determined simply by measuring the virgin rock temperatures in different levels of the mine. All other data directly related with heat emission from different sources has been collected and has been analyzed by using a special computer package. As a conclusion, total heat and moisture content in ventilating air and heat balance has been determined for Karadon Coal Mine. In addition, some recommendations and suggestions have been made for the future works when the mine workings go to the deeper levels.

Jan 1, 1995

By Andre Krzysik

"Fluidized bed technology has been used in the industry for almost 100 years. To fully understand the process hundreds if not thousands of researchers were and are involved in finding the way to predict the behavior of the solids when subjected to the flow of media through them and the conditions of the solids in the fluidized state. The difficulties in predicting the behavior of solids in the fluidized state stem from the complexity and abnormality of the parameters related to the solid particles. Theoretical calculations can in some degree account for some of them. Particle size distribution, their shape, density, moisture content and physical and chemical reaction that may exist in the fluidized bed reactor play an extremely important role and influence the behavior of the fluidized bed. This paper focuses on the practical examples of the fluid bed equipment and the use of different conditions to process various products.IntroductionEach process application has its own unique requirements and the designers of the equipment must take into consideration specific process requirements, specific properties of the material to be processed (both physical and chemical), and physical and chemical reactions/changes that are taking place in the reactor (heat and mass exchange, chemical reactions, isomorphic change etc.). Each individual piece of equipment must also satisfy specific requirements/ preferences of the client that will operate and maintain the equipment. Those often represent greater challenges than the process on its own, and are equally important to the satisfactory operation of the plant. That includes aspects like location of the equipment, environmental effects, and expected life of the equipment, process control, access, maintenance, and many others.Over the period of time a great deal of research, both theoretical and practical have been carried out and the results of that work are available for equipment designers. For the simple applications that information is usually sufficient and the selection of a suitable solution is relatively simple. In many instances, the available information is not sufficient, and often specialized test work needs to be conducted to obtain additional data. In many cases a pilot installation is built in which the required process is tested. Only then the commercial equipment is designed. The following deal with specific installations that were designed to satisfy specific requirements. In some instances, additional problems were discovered during the commissioning of the equipment that required on site modification. The continuous monitoring of the equipment that was supplied to the various clients allowed us to further develop and improve our designs."

Jan 1, 2014

By Larry F. McHugh

Current sulfide ore processing methods involving mechanical sizing of ores, froth flotation, electro-winning, solvent extraction, smelting and roasting are quite effective but typically represent a significant energy and environmental cost. This paper is the subject of a recent patent application and development program involving major improvements in sulfide ore processing. This two-step ?looping oxidation? process effectively removes sulfur while producing materials of adequate purity in an energy proficient and environmentally friendly manner. The first step results in a metal sub-oxide and a highly concentrated sulfur oxide off-gas stream. This gas stream can be processed for recovery in a more effective manner regarding both energy and capital equipment costs. In the second step, this metal sub-oxide is further oxidized to efficiently generate energy that can be recovered and utilized without the typical complications of an ?acid gas? stream process. Additionally, a portion of the final fully oxidized product can be looped back to the first step as the oxidizing agent. This process will be described in detail and compared to existing technologies in the area of energy efficiency, and off-gas environment treatment energy requirements.

Jan 1, 2008

By J. A. Relf

The construction of refineries and gas conservation plants in the general Edmonton area in the early 1950's made available large quantities of by-product liquified petroleum gases (LPG). These gases, together with discovery of increasing reserves of natural gas in the Edmonton area, provided Canadian Chemical Company with two of the necessities for petrochemical production, namely, available and reasonably priced raw materials and fuel. This paper outlines the development of the $83 million Edmonton plant from its origin, together with a brief description of the processes and some of the interesting features involved. Several economic aspects of the petrochemical industry are high-lighted including its importance to the local community and the province. The paper reviews the relationship between the oil and gas industry and petrochemical manufacturing and indicates some of the factors that may affect the future growth of the petro-chemical industry in Wes tern Canada.

Jan 1, 1962

By A. Patton, F. N. Speller

The use of roll scale in the Bessemer process dates back, to the best of our knowledge, at least 20 years. It was first used by the Ohio Steel Go., Youngstown, Ohio (now the Ohio Works of the Carnegie Steel Co.) under the direction of Sam McDonald, Superintendent of the Bessemer Department at these works. Two 10-ton vessels and one blowing engine capable of blowing one heat at a time were employed. The object of using the scale was to shorten the length of the blow, or in other words, to increase the production with the same equipment. Various means were tried out for introducing the roll scale into the bath of molten iron: It was shoveled into the vessel before the heat was charged, so that the metal would flow over the scale; it was shoveled into the bath after the vessel was turned up; it was dumped into the empty iron ladle by the wheelbarrow-load, and at times was dumped on top of the molten metal in the iron ladle. But the practice of introducing the scale into the iron ladle had to be abandoned on account of danger from explosions and of skulling the ladles. It was soon learned that the proper place to charge the scale was in the empty vessel, so that when the molten iron was poured into the vessel it flowed over the scale, causing a considerabIe reaction to take place before the heat was turned up. Eventually, cylindrical chutes similar to those now in use were installed. Into these chutes the scale is dumped and carried into the empty vessel. Before this convenient means of introducing the scale was adopted, the Ohio Works had satisfactorily demonstrated that roll scale would increase production, by blowing 107 heats in one 12-hr. turn (1,087 tons) with one blowing engine, blowing one heat at a time; whereas, prior to the use of scale, the best practice at these works was about 80 heats under the same conditions. In using roll scale and other oxides of iron to facilitate and control the refining of pig iron in the converter, the Bessemer plant has borrowed one of the most active agencies used in the open-hearth process with, as would be expected, much the same results. The effect of such additions to the Bessemer charge may be discussed as to the influence of this practice on quality, production and cost.

Jan 1, 1917

By K Johnson, G Morrison, N Lisowiec

The Mount Wright gold deposit is located near the town of Ravenswood, ~90 km south of Townsville, in north Queensland. The deposit has been mined by underground methods since 2006. It produced approximately 138 koz Au in the 2011 - 2012 financial year and has a total endowment of approximately 1 Moz Au. To facilitate near mine exploration, a re-logging campaign of 600+ diamond and RC drill holes was recently conducted, resulting in a revised three-dimensional (3D) geological model and improved understanding of the ore controls and the mineralised system. The deposit is within a Permo-Carboniferous breccia complex approximately 350 m diameter and more than 1200 m deep. It consists of early peripheral granite-rich breccia, polymict breccia, a rhyolite spine and a late tuffisite (fine-grained milled breccia) pipe. The rhyolite spine is approximately 60 m + 250 m + at least 1200 m deep and is zoned with massive, flow-banded and breccia phases that are in part gradational with the other breccias. There is extensive sericitic alteration centred on the tuffisite and rhyolite units and fading out into the shallower and peripheral polymict and granite-rich breccias. There is also a broad pattern of metal zoning with elevated Pb-Zn ¦ Ag in the upper 400 m, Au-Cu-Bi below 400 m fading out below ~850 m, and a poorly defined deep Mo-W-Te-Sb anomaly. The majority of the Au ore is between 400 and 850 m below the surface in the rhyolite spine. Below this, Au mineralisation is less coherent, and more localised in the margins of the rhyolite and in the adjacent tuffisite. The developing model is that the ore is not confined to or necessarily directly genetically related to the rhyolite spine, but is driven by other phases of intrusion that also generated the tuffisite pipe. This model is being used to generate additional drill targets away from the present mine development.CITATION:Johnson, K, Morrison, G and Lisowiec, N, 2013. Advancing near-mine exploration with an updated geological model for the Mount Wright gold deposit, Queensland, in Proceedings World Gold 2013 , pp 469-478 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By D Reid, J Vinod, M Rahman, A Fourie, T Vo, J Ayala, A Russell

This paper reports on an industry and Australian Research Council funded research project, TAILLIQ, that is a joint initiative between four Australian Universities. The paper discusses the accuracy with which the critical void ratio can be determined for a given tailings; it does this by presenting the results from a ‘round robin’ study in which 18 geotechnical laboratories around the world participated, testing the same tailings (sampled from a gold mine in Western Australia). The results were variable, although a reasonable number were very similar, as described in the paper. The paper provides additional test data for sandy silt gold tailings recovered from a sponsor’s site in Australia, including preliminary calibration chamber test data, results from direct simple shear tests and characterisation tests to determine unsaturated geotechnical properties.

Jul 1, 2021

By N. Menad

The formation of the dioxins can be dependent on the quantities of carbon, hydrogen, chlorine and oxygen present in a given system, as well as on parameters such as temperature and pressure. Inadequate supply of combustion air ( incomplete oxidation ), low combustion temperatures ( incomplete combustion ), and insufficient turbulence in the combustion are factors which can favour their formation. Dioxins were produced also calatytically from chlorinated phenol precursors, non-chlorinated compounds that were chemically, and reaction of phenol with inorganic chloride. In this paper different precursors such as combination of C, H, 0, Cl, rapid formation/combustion intermediates and routes to PCDFs are reviewed, and the influence of PVC amount on the formation of these isomers is discussed.

Jan 1, 2000

By M. Piard

Fires and explosions are not likely to originate in clean gobs above pillar faces steadily driven through a solid panel in order to effect a complete extraction. As. to the storage which such a process implies where the market is intermittent, its cost will never equal that of abandoning large pillars in a fully developed property. Much less will that cost, thanks to the big sizes obtained, ever approach that of cleaning wet and dirty crushings robbed at great expense from small pillars exposed to many years of roof pressure. Even thick seams under bad roof may be fully extracted without the help of filling material. Fatal accidents from falls of roof owing to the great height of excavations, losses in coal, and the danger from fire, have compelled operators in South Staffordshire, England, to discontinue the stall-and-pillar system at one time supreme in the district, and to successfully adopt the following plan: A retreating&apos; longwall is run along the top coal, as the first working; the bottom coal is taken in the same manner, after the fallen roof has become sufficiently consolidated to allow the mine to be reopened. A similar plan is suggested in this paper in order to deal with the outcropping and pitching seams found in the Kootenay measures.

Jan 1, 1930

By G. G. Brown

Enthalpy-entropy diagrams are presented for natural gases of 0.6, 0.7, 0.8, 0.9, and 1.0 gravity over the pressure range of 5 to 10,000 Ib. per sq. in. and temperature range of 32º to 700°F. The charts indicate directly the work requirement and temperature rise for adiabatic compression or temperature change for free emansion of natural eases. Computation and Uses of Charts The Mollier diagram (Fig. 4), in which the enthalpy (heat content) is plotted against the entropy with lines of constant temperature, pressure,, and in some cases volume, has been found most convenient when dealing with the compression, expansion, and flow of fluids. In dealing with the flow of fluids, the sum of the increase in the enthalpy, AH, plus the increase in kinetic energy, AM —, plus the increase in potential energy, ?MZ, representing the total increase in energy of the fluid in flow, is equal to the sum of the heat q, and work added, —w, to the fluid while flowing between the entrance and exit of the flow system. AH + AM— + ?MZ = q-w [1] In cases where there is no significant change in potential energy or in kinetic energy (velocity), it follows that the increase in enthalpy is equal to the total energy supplied to the fluid. Under such conditions&apos; the changes in the property of the fluid as it flows through a throttling valve, choke, or any other similar arrangement, may be read directly from the enthalpy-entropy diagram by following a horizolltal line between the known pressures&apos; When compressing Or expanding a gas by means of a Or or engine in which no heat is added to or subtracted from the gas, but only work done, the changes in the properties of the gas may be determined along a vertical line of constant entropy between the entering and exit pressures. The power required for the compression of the gas may be readily determined by converting the increase in enthalpy into the desired units. The enthalpy-entropy diagram for natural gases is to the gas engineer what the steam diagram is to the steam-power engineer. For this reason it would be extremely convenient if a reasonably satisfactory enthalpy-entropy diagram could be prepared as a function of the gravity of the gas. A careful study of the known properties of natural gas indicate that this is possible. The effect of temperature upon the enthalpy at constant pressure is expressed as the "heat capacity" or "specific heat" of the gas. The best available data for natural and petroleum refinery gases indicates the relationship shown in Fig. I. From this it is clear that the specific heat of natural gases is a function only of the gas gravity and the temperature at atmospheric pressure. The effect of pressure on the enthalpy of natural gases is dependent upon the pressure-volume-temperature relationships,

Jan 1, 1945