Experimental verifying the possibility of predicting hydrocarbon capture degree during pressure absorption using the theory of phase equilibria

UDK: 622.692.4

DOI: 10.24887/0028-2448-2023-5-132-134

Key words: recovery of vapors of oil and oil products, pressure absorption, liquid-gas ejector, theory of phase equilibria

Authors: A.A. Korshak (The Pipeline Transport Institute LLC, RF, Moscow), E.A. Lyubin (Saint-Petersburg Mining University, RF, Staint-Petersburg)

One of the methods for recovering vapors of oil and oil products is their pressure absorption. It is most effectively carried out with low-volatility absorbents. The article presents the results of experimental studies of pressure absorption using a liquid-gas ejector (LGE), their comparison with the calculated values, and conclusions about the possibility of predicting the degree of capture using the apparatus of the theory of phase equilibria are made. This theory has long been successfully used in oil and gas field practice, especially under slowly changing thermodynamic conditions. There is no extreme thermodynamic parameters characteristic of reservoir systems in oil and petroleum product vapor recovery units, which allowed us to hope that the theory of phase equilibria will also be consistent in relation to the calculation of oil and petroleum product vapor recovery units. However, phase transitions occur within a limited time in the LGE, which is not typical for reservoir conditions. To study the possibility of predicting the degree of hydrocarbon capture during pressure absorption, an experimental setup was designed and manufactured. It was a closed loop made of polypropylene pipes with a pump, a liquid-gas ejector, pressure gauges, thermometers, a diesel fuel meter and a separation tank. A mixture of propane-butane with air was supplied to the ejector, where it was mixed with diesel fuel. At the inlet and outlet of the system, the concentration of hydrocarbons in the vapor-air mixture was measured. To study the possibility of predicting the degree of hydrocarbon capture during pressure absorption, an experimental setup was made containing a model of an oil reservoir, a pump, piping, LGE, a separation tank, as well as the necessary measuring instruments. According to the measurement results, the actual values of the degree of hydrocarbon vapor capture were found. In parallel, under the conditions of the experiments, this parameter was calculated using the phase equilibrium constants. The root-mean-square error of calculations was 12.6%. This confirms the possibility of using the apparatus of the theory of phase equilibria to assess the degree of hydrocarbon capture, which will be achieved in real operation at the objects of transportation and storage of oil and oil products. References 1. Sunagatullin R.Z., Korshak A.A., Zyabkin G.V., Current state of vapor recovery when handling oil and oil products (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2017, no. 5, pp. 111–119, DOI:10.28999/2541-9595-2017-7-5-111-119 2. Korshak A.A., Nikolaeva A.V., Nagatkina A.S. et al., Method for predicting the degree of hydrocarbon vapor recovery at absorption (In Russ.), Nauka i tekhnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2020, no. 2, pp. 202–209, DOI:10.28999/2541-9595-2017-7-5-202-209 3. Shilov V.I., Klochkov A.A., Yaryshev G.M., Calculation of the constants of phase equilibrium of natural oil and gas mixtures (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1987, no. 1, pp. 37–39. 4. Gurevich, G.R., Brusilovskiy A.I., Spravochnoe posobie po raschetu fazovogo sostoyaniya i svoystv gazokondensatnykh smesey (A reference manual for calculating the phase state and properties of gas condensate mixtures), Moscow: Nedra, 1984, 264 p. 5. Lutoshkin G.S., Dunyushkin I.I., Sbornik zadach po sboru i podgotovke nefti, gaza i vody na promyslakh (Collection of tasks for the oil, gas and water gathering and treatment in the fields), Moscow: Nedra Publ., 1985, 135 p. 6. Tugunov P.I., Novoselov V.F., Korshak A.A. et al., Tipovye raschety pri proektirovanii i ekspluatatsiy neftebaz i nefteprovodov (Typical calculations in the design and operation of tank farms and oil pipelines), Ufa: Dizain-PoligrafServis Publ., 2002, 658 p. 7. Lyubin E.A., Obosnovanie tekhnologii ulavlivaniya parov nefti iz rezervuarov tipa RVS s ispol'zovaniem nasosno-ezhektornoy ustanovki (Substantiation of the technology for capturing oil vapors from tanks of the RVS type using a pump-ejector unit): thesis of candidate of technical science, St. Petersburg, 2010. 8. Donets K.G., Gidroprivodnye struynye kompressornye ustanovki (The hydraulically driven jet compressor units), Moscow: Nedra Publ., 1990, 174 p. 9. Protod'yakonov L.L., Teder R.I., Metodika ratsional'nogo planirovaniya eksperimentov (Methodology for rational design of experiments), Moscow: Nauka Publ., 1970, 76 p.