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By Y. M. Zhao

Reutilization of waste printed circuit boards (PCB) can not only prevent potential environmental pollution, but also achieve recycling of secondary resources. Study on recycling of discarded PCB belongs to the front edge of environmental pollution prevention and resource recycling. In order to effectively crushing waste PCB, and solve the problem of secondary pollution of fugitive odor and dust during the crushing process, a wet impacting crusher was adopted to achieve comminution liberation of PCB in water medium. 96.79% of the crushed yield was distributed in ?2mm, and metal took 97.18% in this grade of production. Size distribution of PCB particles was characterized double peaks at the sizes of ?1+0.5mm and ?0.074mm. A double Rosin-Rammler function, is called DRR function, is put forward to describe the size distribution of PCB particles. The DRR function of cumulative weight percentage oversize of PCB was non-liner fitted by self-defining DRR function of the Origin 7.0. The evaluation indexes of the fitting results are the correlation coefficients R2 of 0.9994 and residual E of 0.18671, those show that DRR function is perfectly accurate. Based on the research the mechanical separation and material properties of PCB, a wet process of reclaiming metals from PCB using a new style separator ? tapered diameter separation bed (TDSB) in water medium was designed, and the related separation mechanism was studied. The fluid field of the tapered diameter separation equipment was simulated by the Ansys Flotran software, the variation laws of the velocity in each position in the fluid field as well as the equation of axial distribution sectional max velocity were analysed according to the simulation result, the stress change and motion trajectory of the pellet in the certain fluid field were analysed. The results show that the expanding tubular structure of the varied diameter separation bed indicates gradually decreasing velocity of water flow along the axis, assuming a certain angle in the bed, as a result of the gravity?s influence, and there was corresponding change to the distribution of the flow velocity, thus the whole formed a special fluid field where velocity variations exist in different positions. When the material passed through the fluid field along with the water flow, as a result of the difference to the particle density, the granularity and the shape, there would appear the difference to the motion trajectory as well as the movement distance under the action of the fluid: The lower density materials discharge along with water flow, but the higher density materials would be kept in bottom of the bed and discharge through material mouth. Therefore, light and heavy products were separated effectively according to the density. Using tapered diameter separation bed to process the ?1mm size crushed material of waste printed circuit boards, with the discharge of water 5.5m3/h, feed-rate of the material 250g/min and with an obliquity 35°, product with 93.92% in integration efficiency and 93.73% in recovery ratio of the metal were obtained by the primary separation. Compared with other mechanical methods, the range of particle size was broaden using the TDSB to recovery metals from PCB, and lower limit size of separation almost approach to 0. An innovative process of ?wet impact crushing+ classifying+ tapered diameter separation? recycling metals from waste PCB was developed.

Jan 1, 2014

By Shawn Boltz, Erik Westman, Derrick Chambers, Xingdong Zhaoa, Qiankun Zhua

Microseismic passive velocity tomography is becoming an effective technology for large-scale mining-induced stress monitoring in underground mines, especially in the field of early warning of mining-induced hazards. Aiming at the problems of missing low-magnitude events in traditional microseismic monitoring, as well as the potential to increase the resolution of the tomograms in both time and space, a microseismic passive velocity tomography analysis method based on the template matching method was proposed. First, the template matching method was used to pick microseismic events. Then, the probabilistic, non-linear, global-search earthquake location method was used to locate the events and calculate travel time and travel distance. Finally, the fast-marching method was used to carry out passive velocity tomography analysis to image the movement of the abutment stress associated with the longwall. The results show that the selected templates can identify more microseismic events than the traditional microseismic analysis, and the variation trend of events in each day is consistent with the data from the traditional analysis. Using microseismic event locations, travel times and travel distance can effectively complete microseismic passive velocity tomography analysis in each day during the study period and can effectively identify the forward and side abutment stress zones of that longwall panel. This study provides a reference for the identification of mine-induced high stress zones, which has implications for hazard identification and mitigation, with increased resolution of the tomograms in time and space.

Jun 25, 2024

By Z. Y. Ma, M. D. Liu, Z. Z. Liu, J. K. Zhou

"An optimization method of microwave assisted leaching of copper anode slime was proposed based on Taguchi method. The results showed that the solid-liquid ratio was the most important factor affecting SNR(signal noise ratio) of the copper, tellurium and selenium leaching efficiencies, and its contributions to the copper, tellurium and selenium leaching efficiencies were 58.34%, 55.54% and 60.74%, respectively. Solid-liquid ratio was a significant factor to SNR(copper, tellurium and selenium). Reaction period was a less significant factor to SNR(copper and tellurium) and concentration of sulphuric acid was a less significant factor to SNR(selenium) while microwave power was an non-significant factor, its contributions to the copper, tellurium and selenium efficiencies were 3.22%, 11.73% and 12.73%, respectively. The optimized parameters of the microwave assisted leaching of copper were as follow: microwave power of 500 W, reaction period of 10 min, solid-liquid ratio of 0.10 g·mL-1 and H2SO4 concentration of 1.0 mol·L-1. The optimized parameters of the microwave assisted leaching of tellurium and selenium were as follow: microwave power of 800 W, reaction period of 15 min, solid-liquid ratio of 0.10 g·mL-1 and H2SO4 concentration of 1.0 mol·L-1. The validation experiments under the optimized conditions has been carried out, the copper, tellurium and selenium leaching efficiencies were 98.66%, 84.32% and 64.54%, respectively. INTRODUCTION As important valuable by-products, copper anode slimes are collected from the bottom of the electrolytic bath in the electrolytic copper refining process(Kilic, 2013). The value of the anode slime is determined by the content of rare metals and precious metals(Liu, 2014). Generally, pretreatment of copper anode slime is the first stage of the whole process. The aim of the pretreatment process is to remove Cu, Te and Se etc and enrich the valuable metals. The methods of pretreatment process can be differentiated into: pyrometallurgical processing and hydrometallurgical processing(Amer, 2003). The hydrometallurgical processes are more promising compared to pyrometallurgical processes in terms of cost effectiveness, low energy consumption and environmental concerns(Ranjbar, 2014). However, the disadvantages of the hydrometallurgy process are evident, such as lengthy processing times and low efficiency. Therefore, it is necessary to develop a highly efficient and environmentally friendly pretreatment method."

Jan 1, 2018

By QinGuo, Shenghui Guo, Jinhui Peng, Linqing Dai, Libo Zhang

This paper adopts a simple and novel preparation. Taking cellulose as a template, a tubular morphology structure of micro/nano ZnO crystals was obtained by microwave roasting at high temperature. The higher the microwave roasting temperature, the larger the degree of crystallization. The experiments indicate that the best photo catalytic effect can be obtained at 850 : At this temperature, the oxidation of cellulose is complete. Large quantities of hexagonal shaped ZnO crystal can be observed, specifically the (0001) crystal face. Under ultraviolet-visible irradiation, taking long arc mercury lamp as light source, the material had good photocatalytic activity. The decomposing efficiency of methylene blue reaches 97% in 60min, which is superior to that of preparations without templates at the same temperature.

Jan 1, 2016

By Shengli Yang

Solid backfill mining, as a green mining technology, has the advantages of a higher resource recovery, less damage to the environment and the ability to dispose of waste underground. It has been applied successfully in the Xingtai and Xinwen mining areas in China. Strata behavior and the movement of overburden strata in this mining method are very different from fully mechanized longwall mining, which results in a natural caving, because the gob is filled with waste rock, fly ash and other backfill material. The results of field measurements showed that the periodic weighting interval of the main roof is longer; the magnitude of periodic weighting is smaller; the peak and zone of influence of the front abutment pressure are smaller than those in fully mechanized mining; that major deformation of mine roadways occurs within the influence zones of the abutment pressures; that the falling space of immediate roof is smaller, with the lower portion falling more sufficiently than the upper; that the main roof subsides slowly; and that the falling height of the overlying strata is greatly reduced.

Jan 1, 2011

By Tong Guan, Guangqin Fu, Lihong Deng, Yuanlin Chen, Xiaotong Zhou

"In natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the content of MoO3 varies from 2% to 10%. As a result, the flotability of seyrigite (scheelite with molybdenum) turns to be weaker. One seyrigite mine, which has been built for 3 years,still could not produce qualified seyrigite concentrate due to the weak flotability of seyrigite (Mo-bearing scheelite) in raw ore. In our experimental research, through adopting new seyrigite collector TA-3 and advanced mineral processing technology, the seyrigite concentrate with a grade of 65.62% WO3 at a recovery of 87.47% was obtained for the raw ore containing 0.19% WO3 and 0.074% Mo. By applying the new technical achievement, for the raw ore containing 0.272% WO3, the seyrigite concentrate assaying 68.03% WO3 with a recovery of 77.56% was obtained in industrial production.INTRODUCTIONIn natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the scheelite is changed to be seyrigite (Ca[(W,Mo)O4]) (Ma, Bian, & Wang, 2013). The content of MoO3 in seyrigite varies from 2% to 10% usually, the content of MoO3 in some of the seyrigite even reaches 34%. The flotability of seyrigite is weak (Zhang, 2007), and the seyrigite is difficult to be recovered by flotation with common collectors and regulators. One scheelite mine in Anhui China, which is a skarn type seyrigite mine, has not produced qualified concentrate yet since 3 years it has been built due to the limit of beneficiation technology. Therefore, it is necessary to conduct research on the collectors with high efficiency and developing advanced processing flow for this kind of ore."

Jan 1, 2016

By X. L. Song, G. W. Zhang, F. Y. He, X. Xiao, L. L. Huang

This paper presents the design of a model and process simulation of a vertical mill based on a population balance model. The simulator, Simulink, which is a systematic modeling tool within MATLAB, was used for the simulation. The model will simulate the real time variation trend of each size fraction in the feed material to the vertical mill, as well as, the size distribution of the batch grinding products. Breakage distribution and selection functions are calculated based on batch grinding laboratory experiments using Back-calculation method. The simulated size distributions correspond with those in the actual mill operation having a relative error of less than 0.50%. This work lays the foundation for future research on modelling and simulation of a closed circuit grinding operation consisting of a vertical mill with hydrocyclone classifier.

Jan 1, 2016

By Hiroyuki T. Takeshita

Ca-Ni based alloys were investigated on structures, hydrogenation properties and the effect of additive elements on hydrogenation properties. CaNi, samples were decomposed to form a new hydride with a CsCl-type structure on the constituent metal atoms at high temperatures such as 673K in a hydrogen atmosphere. The candidate of the third element which was added to stabilize the original compound was investigated by using the Miedema's semi- empirical model and, as a result, Pd was chosen. The hydrogenation of CaPd was conducted with a Sieverts' type apparatus and the synthesis of Ca-Ni-Pd ternary alloys was performed by high frequency heating.

Jan 1, 2002

THE Institute of Metals Division of the American Institute of Mining and Metallurgical Engineers appointed a Research Committee in 1925 to de-termine what could be done by the Division to promote research work in the United States on non-ferrous metals. It was recognized that a considerable volume of use-ful research work in this field was being carried on by individual industrial companies as well as by the uni-versities and other research institutions, such as the Bureau of Standards. One need only refer to the recent research literature on non-ferrous metals in the TRANS-ACTIONS of the A.I.M.E., and elsewhere, to be con-vinced of healthful research activity in this field. The appointment of the Committee, however, voiced the impression that what was being done was, however excellent, inadequate for the needs of the industry. It was felt that the Division could usefully devote some of its time and effort in stimulating activity in this field. The deliberations of the Research Committee have not failed to develop wide differences of opinion even on the simple questions: (1) whether the Division can aid in any practical manner in this cause and (2) what the features of such aid might be. However, it was clear that there was only one type of research activity with which it could be very usefully concerned, viz., that on subjects of fundamental interest and general application. It was obvious that research work having special objects and more immediate commercial appli-cation should best be left to the industry itself.

Jan 1, 1927

By Xiao-hui Fan, Xu-ling Chen, Zhi-yuan Yu1, Guanghui Li, Min Gan, Yun-song Huang, Tao Jiang

Compared with the traditional de-NOx processes by cleaning the waste gas, a new approach for reducing the formation of NOx during sintering process is proposed. Since more than 90vol% of NOx comes from the fuel combustion, the influence of sintering coke breeze pretreated by CO(NH2)2 additive on the NOx emission is researched. As adding CO(NH2)2, the reduction agents (NHi) are generated during the pyrolysis of CO(NH2)2, which reinforce the NOx reduction, And the appropriate content of CO(NH2)2 is 1.0 mass% of coke breeze.

Jan 1, 2015

By Duanyou Li, Qing Xiao, Zhiwang Wang, Xiaoqing Gan

"Seepage is a major cause of earth-rockfill dam failure. Numerical simulation of infiltration process, distribution of drift, flow velocity and direction after the impoundment can guide seepage control and evaluate its effects. A double field coupling model is established based on soil consolidation theory and the interaction between the seepage field and the temperature field. The simulation is implemented under the situation of core wall setted, core wall not setted, and core wall setted with concentrated leakage. The results indicated that the saturation line height was significantly reduced due to impervious core wall, and the temperature distribution is uniform above the saturation line. If concentrated leakage occurs, temperature distribution of dam was significantly changed, which is consistent with theoretical inference.INTRODUCTIONEngineering seepage field distribution must be calculated in seepage control design, optimization, and correction of new engineering construction of earth dams, as well as in seepage monitoring and evaluation of existing earth-rockfill dams. The aim of calculation is to identify the important parameters in seepage field, such as the coefficient of permeability, seepage flow, pressure, head, and allowable seepage slope, for effectively implementing seepage control design, correction, safety assessment, and anti-seepage reinforcement. These seepage parameters usually can be obtained by in-situ test and back-analysis based on reliable monitoring data.In order to obtain reliable monitoring data and reflect the earth-rockfill dam seepage state and change process, appropriate monitoring technology and monitoring method is necessary. The traditional seepage monitoring method is through site inspection and sensors (e.g., osmometer, piezometric tube and measuring weir) that buried in the structure and its foundation. However, there are still some disadvantages:"

Jan 1, 2015

By C. R. Tang

Due to the current lack of sufficient occupational hazards supervisory staff in China, an occupational hazards supervision regulatory framework is proposed, based on the cloud. Data on respirable dust, noise, heat, toxic and hazardous substances and protection facilities are uploaded to private cloud computing data and service centers to build an occupational hazards supervision system. This system promotes occupational hazards governance. Complex reports are generated. Through the establishment of an occupational hazard supervision data threshold, the dynamic regulation of occupational hazards is accomplished. The main characteristics of this approach are low cost, ease of expansion and maintenance, and strong performance.

Aug 1, 2013

By X. H. Li, F. Xie, Q. Zhang, Z. H. Shen, S. Mao

"There is abundant rare-earth element(REE) in our country, but it is very fragmented in the earth's crust, and it is very difficult to mining or mining cost is extremely high. There are few of industrial value rare-earth deposits. There is a lot of concomitant rare-earth deposits, and the comprehensive utilization value is high. There is very rich carlin-type gold resource, associated with a certain amount of REE in the southwest of Guizhou province. In order toutilize comprehensively the resources, this paper conducts the study on the occurrence characteristics of REE in the ore. By the chemical analysis, the gold grade is 3.35g/t, the organic carbon 0.81%, the total REE 0.022%, which is a high carbon fine disseminated gold ore. By the optical microscope and XRD analysis, the major minerals are quartz, pyrite, calcite, limonite, arsenopyrite, mica, kaolinite, clay minerals, etc. In addition, there is a large amount of carbonaceous materials, such as organic carbon, graphite, which is harmful on leaching of gold. By the scanning electron microscopy analysis, there are thorium, lanthanum and neodymium, ytterbium, persimmon and other REE in the ore. Gravity separation shows that REE could be enriched to lighter material mainly, which indicates that REE disseminate closely with lighter materials.INTRODUCTION Carlin-type gold ore is important gold resource in the world, which are mainly distributed in Nevada and its vicinity, as well as the two Golden Triangle of Yunnan, Guizhou, Guangxi and Sichuan, Shanxi, Gansu province in China(Su W.C. et al.,2009; Xia G.X.,1996).Guizhou carlin-type gold ore is the second largest gold resource in the world(Muntean J L et al.,2011), distributing along the southwestern margin of the Yangtze plate, mainly mineralizing in the neopaleozoic-early mesozoic(Xie Z J et al.,2017). Many large gold deposits have been found in southwest in Guizhou in twentieth century, such as Zimuyou,Getang, Lannigou, Shuiyindong and Laowanchang gold deposit, and so on, and the gold reserves reach over 100 tons(Xia Y. et al.,2009).There is a certain amount of rare-earth resource in the carlin-type gold ore in the southwest in Guizhou province, and the current researches might mainly focus on characteristics of REE from the angle of geological mineralization(AnanyevY.,2015), not from the angle of separation and enrichment."

Jan 1, 2018

By Masaharu Moteki

At present, the Unmanned Construction System (UCS) is adapted on initial operation against the disaster. For instance, it has been used in Unzen. When the scale of the disaster is big, or the danger to a person is big, the UCS is expected as a quick and safe construction technology. The Remote Controlled UCS is introduced into construction site to repair earth-fill embankment or to remove rock, as urgent measures after the disaster outbreak. For improvement of the operability, shortening of the skill time, reduction of the fatigue, examination of the most suitable system (placement of a monitor and the joy stick) of the remote system is a main theme in the Public Works Research Institute (PWRI). In the report of this year, when the operator controls construction machine directly or he controls it using remote system (he can check the situation of site only via monitor), the degree of achievement, construction efficiency and construction precision were inspected. The remote system which is based on the system used at Unzen was developed at PWRI.

Aug 1, 2013

By Zhiqiang Zhou, Libin Zhu, Zizong Zhu, Hao Xiong, Yuchuan Ding

In order to utilize the lean ore resources from XinJiang rationally and optimize mixture, laborarory measurements have been carried out under different basicity, various mixed carbon content as well as the properties (ratio) of fuel particle size by the sintering pot for further microstructure analyses. The results show that sinter strength falls by 5.0%, low temperature reduction disintegration index (RDI) drops off to the lowest in certain ranges. The natural degradation index of sinter is much higher when sinter basicity is between 1.65 and 1.75. The sinter strength increases when sinter basicity is between 1.75 and 2.0. Meanwhile, the sinter strength and RDI +3.15 improve with increasing carbon content. And the sinter strength and RDI+3.15 both decrease with the decrease of the distribution ratio of small fuel particle, thereby decreases the yield of sinter. Microstructural analyses have been investigated to figure out the mechanism of the influence of the three factors on sinter.

Mar 1, 2017

By Guangliang Wu, Dongchang Huang, Xinbin Liu

Oxidation Kinetics of SPHC was analyzed by TGA, and the curve of oxidation weight gain with different temperature was acquired. It is found that, when the oxidation temperature is between 500 and 600 , all the curves are linear; when the oxidation temperature is above 700 , the curves are close to parabolic. At the temperature of 900 , the oxidation weight gain increases dramatically. The TGA results indicate that the activation energy of SPHC steel is 146.19 kJ/mol at the temperature of 500 900 , and an oxidation kinetic model was set up for variable temperature. Based on the temperature change during rolling process, numerical simulation of oxide scales evolution was carried out for SPHC steel, and the simulation result agreed well with measured ones. It can provide a basis for estimating the scale growth and controlling the temperature on site.

Jan 1, 2016

By B. H. Sage, W. N. Lacey

The growing background of experimental information concerning the volumetric and phase behavior of binary and ternary hydrocarbon systems is used as the basis for a comparison of these systems with naturally occurring hydrocarbon mixtures under conditions representative of underground petroleum reservoirs. The qualitative and semiquantitative similarities and differences between the two types of systems are considered in reference to the possibilities and limitations of using experimental data on binary and ternary systems for predicting the volumetric and phase behavior of naturally occurring hydrocarbon mixtures of low molecular weight. The possible influence on such phase behavior of water, hydrogen sulphide, nitrogen, and components of relatively high molecular weight is discussed. INTRODUCTION During the past two decades much effort has been devoted to the study of the volumetric and phase behavior of pure paraffin hydrocarbons and of binary and ternary mixtures of these compounds. Many of these studies were carried out with the direct objective of utilizing a knowledge of the detailed characteristics of binary and ternary mixtures of the lighter paraffin hydrocarbons for predicting the behavior of more complex mixtures. The ability to make such predictions with accuracy would be of great value in petroleum production and refining. Although the behavior of the methane-propane system' served at one time as a qualitative illustration of the probable characteristics of the more complex hydrocarbon mixtures found in nature, it' fell far short of requirements for quantitative predictions. The present paper endeavors to indicate the relation of the more recently accumulated information concerning the behavior of binary and ternary hydrocarbons to this problem. In discussing binary and ternary systems as examples pointing toward the behavior of multi-component systems no effort is made to present new methods of predicting the characteristics of natural hydrocarbon mixtures. Preliminary proposals have been made elsewhere for the prediction of volumetric phase equilibrium and thermodynamic data for multicomponent mixtures, utilizing as a basis the behavior of binary and ternary systems. Numerous other proposals have been made. That based upon the concept of a pseudo-critical state" has proved to be of value to the petroleum industry. Concurrently with this study of binary and ternary systems investigations have been made of natural hydrocarbon systems. Of the many publications reporting such experimental information only a few examples will be mentioned. A number of studies of black oil and natural gas have been made and much attention has been directed to extended and detailed investigations of the behavior of fluids in condensate fieldS 16,17,18,19,20. This work has been supplemented by some studies of the separation of bitumen from natural hydrocarbon liquids The over-all behavior of such systems has been used in predicting the volumetric and phase behavior of naturally occurring mixtures This background of experimental and correlated information concerning the behavior of multicomponent hydrocarbon systems also permits a direct comparison of the characteristics of binary and ternary aliphatic systems with those materials produced from underground reservoirs. PRESENTATION OF DATA The primary limitation encountered in using binary and ternary aliphatic hydrocarbon mixtures as examples of the characteristics of the fluids encountered in underground reservoirs lies in the existing lack of knowledge of the quantitative effect upon behavior of the presence of several important constituents, notably hydrocarbons of high molecular weight, water, carbon dioxide, hydrogen sulphide, and nitrogen. The presence of substantial quantities of hydrocarbons of fairly high molecular weight serves to increase the complexity of the phase behavior of natural systems. No simple systems yet studied give adequate guidance in this regard. The influence of such materials of high molecular weight was indicated earlier",?' to an extent which serves to show that definite limitations now exist in the correlation of simple and complex systems. However, significant progress is being made in filling gaps in the information. For example, similarities in the behavior of fluids in condensate fields with that of binary and ternary systems are becoming more systematically evident. A few studies of the behavior of water in paraffin hydrocarbon systems have been made Results of investigations of mixtures of carbon dioxide and the lighter hydrocarbons also are available Limited work has been reported con-

Jan 1, 1949

By W. N. Lacey, B. H. Sage

The growing background of experimental information concerning the volumetric and phase behavior of binary and ternary hydrocarbon systems is used as the basis for a comparison of these systems with naturally occurring hydrocarbon mixtures under conditions representative of underground petroleum reservoirs. The qualitative and semiquantitative similarities and differences between the two types of systems are considered in reference to the possibilities and limitations of using experimental data on binary and ternary systems for predicting the volumetric and phase behavior of naturally occurring hydrocarbon mixtures of low molecular weight. The possible influence on such phase behavior of water, hydrogen sulphide, nitrogen, and components of relatively high molecular weight is discussed. INTRODUCTION During the past two decades much effort has been devoted to the study of the volumetric and phase behavior of pure paraffin hydrocarbons and of binary and ternary mixtures of these compounds. Many of these studies were carried out with the direct objective of utilizing a knowledge of the detailed characteristics of binary and ternary mixtures of the lighter paraffin hydrocarbons for predicting the behavior of more complex mixtures. The ability to make such predictions with accuracy would be of great value in petroleum production and refining. Although the behavior of the methane-propane system' served at one time as a qualitative illustration of the probable characteristics of the more complex hydrocarbon mixtures found in nature, it' fell far short of requirements for quantitative predictions. The present paper endeavors to indicate the relation of the more recently accumulated information concerning the behavior of binary and ternary hydrocarbons to this problem. In discussing binary and ternary systems as examples pointing toward the behavior of multi-component systems no effort is made to present new methods of predicting the characteristics of natural hydrocarbon mixtures. Preliminary proposals have been made elsewhere for the prediction of volumetric phase equilibrium and thermodynamic data for multicomponent mixtures, utilizing as a basis the behavior of binary and ternary systems. Numerous other proposals have been made. That based upon the concept of a pseudo-critical state" has proved to be of value to the petroleum industry. Concurrently with this study of binary and ternary systems investigations have been made of natural hydrocarbon systems. Of the many publications reporting such experimental information only a few examples will be mentioned. A number of studies of black oil and natural gas have been made and much attention has been directed to extended and detailed investigations of the behavior of fluids in condensate fieldS 16,17,18,19,20. This work has been supplemented by some studies of the separation of bitumen from natural hydrocarbon liquids The over-all behavior of such systems has been used in predicting the volumetric and phase behavior of naturally occurring mixtures This background of experimental and correlated information concerning the behavior of multicomponent hydrocarbon systems also permits a direct comparison of the characteristics of binary and ternary aliphatic systems with those materials produced from underground reservoirs. PRESENTATION OF DATA The primary limitation encountered in using binary and ternary aliphatic hydrocarbon mixtures as examples of the characteristics of the fluids encountered in underground reservoirs lies in the existing lack of knowledge of the quantitative effect upon behavior of the presence of several important constituents, notably hydrocarbons of high molecular weight, water, carbon dioxide, hydrogen sulphide, and nitrogen. The presence of substantial quantities of hydrocarbons of fairly high molecular weight serves to increase the complexity of the phase behavior of natural systems. No simple systems yet studied give adequate guidance in this regard. The influence of such materials of high molecular weight was indicated earlier",?' to an extent which serves to show that definite limitations now exist in the correlation of simple and complex systems. However, significant progress is being made in filling gaps in the information. For example, similarities in the behavior of fluids in condensate fields with that of binary and ternary systems are becoming more systematically evident. A few studies of the behavior of water in paraffin hydrocarbon systems have been made Results of investigations of mixtures of carbon dioxide and the lighter hydrocarbons also are available Limited work has been reported con-

Jan 1, 1949

By Carl H. Unruh, D. L. Katz

Experimental data are presented for hydrate formation conditions for gas mixtures of carbon dioxide and methane. Equilibrium constants for carbon dioxide, defined as the mole fraction of carbon dioxide in the gas phase (dry basis) divided by the mole fraction of carhon dioxitle in the hydrate (dry basis)... were calculated usine the equilibrium constants for methane developed in an earlier paper. INTRODUCTION A series of papers have been written on gas hydrates, giving temperatures and pressures at which hydrates would form.2. 3, 4. 5, 6. 9. 12, 13, 15 Vapor-solid equilibrium constants have been developed for methane, ethane, propane and iso-butane' by which it is possible to compute for a specific gas mixture the temperature and pressure at which hydrates will form. Carbon dioxide is present in many natural gases in concentrations usually from 0.1 to 2.0 per cent. It also forms a gas hydrate with water and presumably enters the solid solution when present with a natural gas which is forming a hydrate. The equilibrium constant giving the ratio of the concentration of carbon dioxide in the gas phase to the concentration in the solid phase is required for including the effect of the carbon dioxide when computing the conditions for hydrate formation. Direct determination of the concentration of carbon dioxide in solid hydrate requires a difficult separation to be made. Therefore, this research resorted to the measurement of the temperature and pressure at which specific mixtures of methane and carbon diox- ide would form hydrates. From the equilibrium constants previously mentioned for methane, it is possible to compute the equilibrium constant for carbon dioxide, without measurement of the composition of the solid phase. Fig. 1 shows the conditions at which methane and carbon dioxide form hydrates. The methane curve FG extents to some high pressure while the carbon dioxide curve AB intersects the vapor-liquid water-liquid carbon dioxide

Jan 1, 1949

By Carl H. Unruh, D. L. Katz

Experimental data are presented for hydrate formation conditions for gas mixtures of carbon dioxide and methane. Equilibrium constants for carbon dioxide, defined as the mole fraction of carbon dioxide in the gas phase (dry basis) divided by the mole fraction of carhon dioxitle in the hydrate (dry basis)... were calculated usine the equilibrium constants for methane developed in an earlier paper. INTRODUCTION A series of papers have been written on gas hydrates, giving temperatures and pressures at which hydrates would form.2. 3, 4. 5, 6. 9. 12, 13, 15 Vapor-solid equilibrium constants have been developed for methane, ethane, propane and iso-butane' by which it is possible to compute for a specific gas mixture the temperature and pressure at which hydrates will form. Carbon dioxide is present in many natural gases in concentrations usually from 0.1 to 2.0 per cent. It also forms a gas hydrate with water and presumably enters the solid solution when present with a natural gas which is forming a hydrate. The equilibrium constant giving the ratio of the concentration of carbon dioxide in the gas phase to the concentration in the solid phase is required for including the effect of the carbon dioxide when computing the conditions for hydrate formation. Direct determination of the concentration of carbon dioxide in solid hydrate requires a difficult separation to be made. Therefore, this research resorted to the measurement of the temperature and pressure at which specific mixtures of methane and carbon diox- ide would form hydrates. From the equilibrium constants previously mentioned for methane, it is possible to compute the equilibrium constant for carbon dioxide, without measurement of the composition of the solid phase. Fig. 1 shows the conditions at which methane and carbon dioxide form hydrates. The methane curve FG extents to some high pressure while the carbon dioxide curve AB intersects the vapor-liquid water-liquid carbon dioxide

Jan 1, 1949