Calculation of phase transitions in condensation units for recovery of oil and oil products vapors

UDK: 622.692.4
DOI: 10.24887/0028-2448-2021-6-98-101
Key words: recovery of oil and oil products vapors, low-temperature condensation, phase equilibrium constants, equation of phase concentrations, approximation
Authors: Calculation of phase transitions in condensation units for recovery of oil and oil products vapors

The article discusses the method of calculating the condensation of hydrocarbons contained in the gas-air mixture displaced from the tanks and vehicles when they are filled. Currently, there is a wide range of software products that allow high-precision modeling of various technological processes, including low-temperature condensation. However, foreign software products are expensive and therefore inaccessible for widespread use. At the same time, in the practice of designing and analyzing technological processes of oil and gas production and oil and gas processing, the equations of phase concentrations are widely used. They require a minimum amount of initial data for the calculation: information on the composition of the gas-air mixture, as well as on the thermodynamic conditions of the process (pressure and temperature). However, in most works, recommendations for calculating the phase equilibrium constants are given in relation to positive temperatures, which is typical for reservoir conditions and conditions for separation of reservoir fluids. Low-temperature separation processes of multicomponent hydrocarbon mixtures in the field are also common. For example, the extraction of hydrocarbon condensate from gas at complex treatment plants is carried out at temperatures up to -40 °C. However, according to foreign data, to ensure a high degree of capture of oil and gasoline vapors, it is necessary to cool the gas-air mixtures to a temperature of -60 °C or less. Therefore, the currently known methods for determining the phase equilibrium constants, which are not intended for a given temperature range, cannot be used in the calculations of condensation units for recovering hydrocarbons.

With the use of relatively complex well-known techniques a data bank was developed on the dependence of the value of the phase equilibrium constants of individual components of the gas-air mixture on temperature at atmospheric pressure, which takes place in condensation units for recovering vapors of oil and oil products. Then, the obtained numerical values of these constants were approximated by a fairly simple dependence that is convenient for use.

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 tekhnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2017, no. 5, pp. 111–119.

2. 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.

3. 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.

4. 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.

5. Je-Lueng Shie, Chen-Yu Lu, Ching-Yuan Chang et al., Recovery of gasoline vapors by a combined two-stage dehydration and condensation process (In Russ.), Zhurnal Kitayskogo instituta khimicheskoy inzhenerii, 2003, V. 34, no. 6, pp. 605–616.

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. Gurevich G.R., Karlinskiy E.D., Separatsiya prirodnogo gaza na gazokondensatnykh mestorozhdeniyakh (Separation of natural gas in gas condensate fields), Moscow: Nedra Publ., 1982, 197 p.

8. RD 39-1-348-80. Metodika rascheta fazovykh ravnovesiy i fizicheskikh svoystv faz neftegazokondensatnykh sistem (Method for calculating phase equilibria and physical properties of phases of oil and gas condensate systems), Moscow: Publ. of ONTI VNII, 1980, 85 p.

9. Wilson G.A., A modified Redlich–Kwong EOS. Application physical data calculation, In: Paper 15C presented at the annual AICHE National Meeting, Cleveland, 1968, May 4–7.

10. Whitson C.H., Torp S.B., Evaluating constant volume depletion data, JPT Trans. AIME, 1983, V. 35 no. 3, pp. 610–620.

11. DePriester C.L., Light-hydrocarbon vapor-liquid distribution coefficients. Pressure-temperature-composition charts and pressure-temperature nomographs, Chem. Eng. Prog. Symp. Ser., 1953, V. 49, no. 7, pp. 41–45.

12. McWilliams M., An equation to relate K-factors to pressure and temperature, Chem. Eng., 1973, V. 80 (25), pp. 138–140.

13. Almehaideb R.A., Ashour I., El-Fattah K.A., Improved K-values correlation for UAE crude oil components at low pressures using PVT laboratory data, Fuel, 2001, V. 80, pp. 117-124, DOI:10.1016/S0016-2361(00)00064-8

14. Reid R.C., Prausnitz J.M., Sherwood T.K., The properties of gases and liquids, New York: McGraw-Hill, 1977.

15. 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.

The article discusses the method of calculating the condensation of hydrocarbons contained in the gas-air mixture displaced from the tanks and vehicles when they are filled. Currently, there is a wide range of software products that allow high-precision modeling of various technological processes, including low-temperature condensation. However, foreign software products are expensive and therefore inaccessible for widespread use. At the same time, in the practice of designing and analyzing technological processes of oil and gas production and oil and gas processing, the equations of phase concentrations are widely used. They require a minimum amount of initial data for the calculation: information on the composition of the gas-air mixture, as well as on the thermodynamic conditions of the process (pressure and temperature). However, in most works, recommendations for calculating the phase equilibrium constants are given in relation to positive temperatures, which is typical for reservoir conditions and conditions for separation of reservoir fluids. Low-temperature separation processes of multicomponent hydrocarbon mixtures in the field are also common. For example, the extraction of hydrocarbon condensate from gas at complex treatment plants is carried out at temperatures up to -40 °C. However, according to foreign data, to ensure a high degree of capture of oil and gasoline vapors, it is necessary to cool the gas-air mixtures to a temperature of -60 °C or less. Therefore, the currently known methods for determining the phase equilibrium constants, which are not intended for a given temperature range, cannot be used in the calculations of condensation units for recovering hydrocarbons.

With the use of relatively complex well-known techniques a data bank was developed on the dependence of the value of the phase equilibrium constants of individual components of the gas-air mixture on temperature at atmospheric pressure, which takes place in condensation units for recovering vapors of oil and oil products. Then, the obtained numerical values of these constants were approximated by a fairly simple dependence that is convenient for use.

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 tekhnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2017, no. 5, pp. 111–119.

2. 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.

3. 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.

4. 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.

5. Je-Lueng Shie, Chen-Yu Lu, Ching-Yuan Chang et al., Recovery of gasoline vapors by a combined two-stage dehydration and condensation process (In Russ.), Zhurnal Kitayskogo instituta khimicheskoy inzhenerii, 2003, V. 34, no. 6, pp. 605–616.

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. Gurevich G.R., Karlinskiy E.D., Separatsiya prirodnogo gaza na gazokondensatnykh mestorozhdeniyakh (Separation of natural gas in gas condensate fields), Moscow: Nedra Publ., 1982, 197 p.

8. RD 39-1-348-80. Metodika rascheta fazovykh ravnovesiy i fizicheskikh svoystv faz neftegazokondensatnykh sistem (Method for calculating phase equilibria and physical properties of phases of oil and gas condensate systems), Moscow: Publ. of ONTI VNII, 1980, 85 p.

9. Wilson G.A., A modified Redlich–Kwong EOS. Application physical data calculation, In: Paper 15C presented at the annual AICHE National Meeting, Cleveland, 1968, May 4–7.

10. Whitson C.H., Torp S.B., Evaluating constant volume depletion data, JPT Trans. AIME, 1983, V. 35 no. 3, pp. 610–620.

11. DePriester C.L., Light-hydrocarbon vapor-liquid distribution coefficients. Pressure-temperature-composition charts and pressure-temperature nomographs, Chem. Eng. Prog. Symp. Ser., 1953, V. 49, no. 7, pp. 41–45.

12. McWilliams M., An equation to relate K-factors to pressure and temperature, Chem. Eng., 1973, V. 80 (25), pp. 138–140.

13. Almehaideb R.A., Ashour I., El-Fattah K.A., Improved K-values correlation for UAE crude oil components at low pressures using PVT laboratory data, Fuel, 2001, V. 80, pp. 117-124, DOI:10.1016/S0016-2361(00)00064-8

14. Reid R.C., Prausnitz J.M., Sherwood T.K., The properties of gases and liquids, New York: McGraw-Hill, 1977.

15. 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.



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