Vapor‐liquid equilibrium of hydrogen/tetralin system at elevated temperatures and pressures

Abstract

A flow type of apparatus is built to give equilibrium gas and liquid samples at elevated pressures and temperatures while minimizing thermal decomposition. Saturated vapor and liquid compositions and K values are determined with this apparatus for the binary system hydrogen/tetralin (1,2,3,4-tetrahydronaphthalene) at SCOPEThis work extends experimental investigation of phase equilibrium of hydrogedheavy solvent systems to elevated pressures and temperatures of interest in hydro treating processes, particularly coal liquefaction processes. Information on the amount of dissolved hydrogen in the liquid phase is useful for analysis of reaction mechanism and for engineering design of blowdown and associated separation systems.Previous studies of the phase equilibrium of hydrogen/ solvent systems have been limited to relatively low temperatures. An exception is found in the work by Grayson and Streed (1963) in which a correlation of K values of hydrogen in heavy oils was presented for temperatures and pressures comparable to this work, but no detailed experimental data were given.The system hydrogedtetralin reported here is the first system studied in the new flow type of apparatus we have just built. The study is being continued with other hydrogen mixture systems. The data gathered with various types of solvents will contribute to the development of general quantitative description of the solubility of hydrogen in complex liquid mixtures. CONCLUSIONS AND SIGNIFICANCEVapor-liquid equilibrium in hydrogen/solvent systems has been the subject of a great deal of investigation owing to their industrial importance and scientific interest. The development of hydro treating and coal liquefaction processes generated renewed interest focused on conditions of high temperature and pressure and on heavy solvents. In this work we built a new flow type of apparatus and showed that equilibrium data can be obtained from it with small residence times of the samples in the high temperature zone. Thermal decomposition is minimized as residence time is reduced, making possible determination of equilibrium data at high temperatures that would otherwise lead to excessive decomposition.That equilibrium is attained in the apparatus at the conditions of operation is supported by the positive results obtained from three tests:1. The sample compositions are independent of flow rates within the range of flow rates employed.2. Data on hydrogedbenzene from our apparatus agree with results obtained by Connolly (1962) from a static apparatus.3. The new data on hydrogedtetralin satisfy the GibbsDuhem equation.Equilibrium saturated liquid and gas compositions and K values are determined for the binary system hydrogen/ tetralin at four temperatures (189. 6O, 268.7O, 348.6O, 389.1OC) and seven pressures (20, 30, 50, 100, 150, 200, 250 am). Henry constant of hydrogen is determined from the data. The results are useful for modeling the phase behavior of hydro treating and coal liquefaction processes. Since tetralin is widely used as a hydrogen-donor s...

The Impact of Trace Additives on the Apparent Solubility of Hydrogen in Heavy Oil and Related Feedstocks at Low and High Temperatures

“…The most commonly used techniques can be grouped as direct and indirect methods. In typical direct measurement methods [8][9][10][11], a known amount of liquid at equilibrium is sampled and hydrogen solubility is measured using gas chromatography.…”

Phase equilibria in supercritical propane systems for separation of continuous oil mixtures

“…In this method, all the feed components ftow through an equilibrium cell at steady state. In contrast to batch techniques, the ftow techniques {Chao et al , 1964;Simnick et al, 1977;Wilson and Owens, 1977) not only can generate large samples but also allow for short residence times as required for thermally-unstable liquids.…”

Improvement of hydrogen solubility and entrainment in hydrocracker feedstocks. Final technical report

“…Sokolov V. L, and Polyakov, A. A., Zhurnal Prikladnoi Khimii, 50(6), 1405, 1977 .94. Speight, J. G., and Moschopedis, S. E., Fuel Prcc.…”

“…Such information is useful not only for the engineering design of gas-liquid contacting and separation equipment but also for the study of reaction kinetics in coal liquefaction mixtures (Simnick et al , 1977;Sebastian et al , 1978). Gas-solubility information at elevated temperatures and pressures is also an important parameter in high pressure processes such as coal liquefaction (Matsurnoto and Satterfield, 1985) and for the design of gas absorption and stripping columns i n chemical industries.…”

“…Simnick et al (1977) have found that equilibrium Can be attained at short residence times at high temperatures using a flow type of . * .…”