Skip to main content

Optimal design of a novel NGL/LNG integrated scheme: economic and exergetic evaluation


A novel NGL/LNG integrated scheme based on C3MR refrigeration system is modeled by using Aspen plus® in this study. The mentioned scheme utilizes mixed refrigerant to provide some of the required cooling in the ethane recovery unit, in addition to producing LNG with the low power consumption. The optimal operating conditions for the proposed configuration are determined by considering the earned profit. For this, a surrogate model is formulated by exploring the design space based on the response surface methodology. The optimal conditions from the mathematical model are obtained using genetic algorithm. The results show that the products sales revenue increases by 88% in the proposed scheme, while 26.65% of this increased revenue is spent on the increased investment and operational costs. Most of these costs belong to the added compressors and cryogenic shell and tube heat exchangers. Moreover, ethane recovery is increased by 25% in the proposed scheme compared to the industrial plant, while the cost of steam consumption is reduced by 11.61%. The exergy analysis shows that the overall efficiency is 53.67% for the proposed configuration and 71.79% of the total exergy destruction occurs in the LNG unit. The compressors of this unit have the highest share in the exergy destruction.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9



Annualized revenue ($ year −1)


Bare-module cost ($)

C :

Cost ($)


Earned profit ($ year −1)


Exergy (kW)


Increased annualized revenue ($ year −1)


Increased electricity cost ($ year −1)


Increased steam cost ($ year −1)


Minimum temperature approach (°C)

P :

Pressure (bar)

Q :

Heat transfer rate (kW)


Steam cost ($ year −1)


Specific power energy consumption (kWh kg−1 LNG)

T :

Temperature (°C)


Total increased annualized cost ($ year −1)


Total increased bare-module investment ($)


Total increased capital investment ($)


Total increased operating cost ($ year −1)


Overall heat transfer coefficient and area of heat exchanger

W :

Electrical power (kW)

x :

Actual manipulated variable

\(\bar{x}\) :

Coded manipulated variable


Analysis of variance


Aspen process economic analyzer


Box–Behnken design


Propane precooled mixed refrigerant


Double mixed refrigerant


Genetic algorithm


Heat exchanger




Knowledge-based optimization


Liquefied natural gas


Low pressure


Mixed fluid cascade


Mixed refrigerant


Mean square


Million tons per annum


Natural gas


Natural gas liquid


Non-dominated sorting genetic algorithm II


Single mixed refrigerant


Sequential quadratic programming








Heat rate


  1. BP energy outlook, British Petroleum, London, England, 2019.

  2. Lim W, Lee I, Tak K, Cho JH, Ko D, Moon I. Efficient configuration of a natural gas liquefaction process for energy recovery. Ind Eng Chem Res. 2014;53(5):1973–85.

    CAS  Google Scholar 

  3. Mazyan W, Ahmadi A, Ahmed H, Hoorfar M. Market and technology assessment of natural gas processing: a review. J Nat Gas Sci Eng. 2016;30:487–514.

    CAS  Google Scholar 

  4. Khan MS, Lee S, Getu M, Lee M. Knowledge inspired investigation of selected parameters on energy consumption in nitrogen single and dual expander processes of natural gas liquefaction. J Nat Gas Sci Eng. 2015;23:324–37.

    CAS  Google Scholar 

  5. Khan MS, Karimi IA, Wood DA. Retrospective and future perspective of natural gas liquefaction and optimization technologies contributing to efficient LNG supply: a review. J Nat Gas Sci Eng. 2017;45:165–88.

    Google Scholar 

  6. Lee S, Long NV, Lee M. Design and optimization of natural gas liquefaction and recovery processes for offshore floating liquefied natural gas plants. Ind Eng Chem Res. 2012;51(30):10021–30.

    CAS  Google Scholar 

  7. Shirazi MM, Mowla D. Energy optimization for liquefaction process of natural gas in peak shaving plant. Energy. 2010;35(7):2878–85.

    CAS  Google Scholar 

  8. Xu X, Liu J, Jiang C, Cao L. The correlation between mixed refrigerant composition and ambient conditions in the PRICO LNG process. Appl Energy. 2013;102:1127–36.

    CAS  Google Scholar 

  9. Khan MS, Lee M. Design optimization of single mixed refrigerant natural gas liquefaction process using the particle swarm paradigm with nonlinear constraints. Energy. 2013;49:146–55.

    Google Scholar 

  10. Moein P, Sarmad M, Ebrahimi H, Zare M, Pakseresht S, Vakili SZ. APCI-LNG single mixed refrigerant process for natural gas liquefaction cycle: analysis and optimization. J Nat Gas Sci Eng. 2015;26:470–9.

    CAS  Google Scholar 

  11. Park JH, Khan MS, Lee M. Modified coordinate descent methodology for solving process design optimization problems: application to natural gas plant. J Nat Gas Sci Eng. 2015;27:32–41.

    Google Scholar 

  12. Qyyum MA, Ali W, Long NV, Khan MS, Lee M. Energy efficiency enhancement of a single mixed refrigerant LNG process using a novel hydraulic turbine. Energy. 2018;144:968–76.

    Google Scholar 

  13. Lee I, Moon I. Total cost optimization of a single mixed refrigerant process based on equipment cost and life expectancy. Ind Eng Chem Res. 2016;55(39):10336–43.

    CAS  Google Scholar 

  14. Pham TN, Long NV, Lee S, Lee M. Enhancement of single mixed refrigerant natural gas liquefaction process through process knowledge inspired optimization and modification. Appl Therm Eng. 2017;110:1230–9.

    CAS  Google Scholar 

  15. Ali W, Qyyum MA, Qadeer K, Lee M. Energy optimization for single mixed refrigerant natural gas liquefaction process using the metaheuristic vortex search algorithm. Appl Therm Eng. 2018;129:782–91.

    CAS  Google Scholar 

  16. He T, Liu Z, Ju Y, Parvez AM. A comprehensive optimization and comparison of modified single mixed refrigerant and parallel nitrogen expansion liquefaction process for small-scale mobile LNG plant. Energy. 2019;167:1–2.

    CAS  Google Scholar 

  17. He T, Mao N, Liu Z, Qyyum MA, Lee M, Pravez AM. Impact of mixed refrigerant selection on energy and exergy performance of natural gas liquefaction processes. Energy. 2020;199:117378.

    CAS  Google Scholar 

  18. Alabdulkarem A, Mortazavi A, Hwang Y, Radermacher R, Rogers P. Optimization of propane pre-cooled mixed refrigerant LNG plant. Appl Therm Eng. 2011;31(6–7):1091–8.

    CAS  Google Scholar 

  19. Wang M, Zhang J, Xu Q, Li K. Thermodynamic-analysis-based energy consumption minimization for natural gas liquefaction. Ind Eng Chem Res. 2011;50(22):12630–40.

    CAS  Google Scholar 

  20. Wang M, Zhang J, Xu Q. Optimal design and operation of a C3MR refrigeration system for natural gas liquefaction. Comput Chem Eng. 2012;39:84–95.

    Google Scholar 

  21. Khan MS, Lee S, Rangaiah GP, Lee M. Knowledge based decision making method for the selection of mixed refrigerant systems for energy efficient LNG processes. Appl Energy. 2013;111:1018–31.

    CAS  Google Scholar 

  22. Castillo L, Dorao CA. On the conceptual design of pre-cooling stage of LNG plants using propane or an ethane/propane mixture. Energy Convers Manag. 2013;65:140–6.

    CAS  Google Scholar 

  23. Pereira C, Lequisiga D. Technical evaluation of C3-MR and cascade cycle on natural gas liquefaction process. Int J Chem Eng Appl. 2014;5(6):451.

    CAS  Google Scholar 

  24. Khan MS, Karimi IA, Bahadori A, Lee M. Sequential coordinate random search for optimal operation of LNG (liquefied natural gas) plant. Energy. 2015;89:757–67.

    CAS  Google Scholar 

  25. Sanavandi H, Ziabasharhagh M. Design and comprehensive optimization of C3MR liquefaction natural gas cycle by considering operational constraints. J Nat Gas Sci Eng. 2016;29:176–87.

    CAS  Google Scholar 

  26. Najibullah Khan NB, Barifcani A, Tade M, Pareek V. A case study: application of energy and exergy analysis for enhancing the process efficiency of a three stage propane pre-cooling cycle of the cascade LNG process. J Nat Gas Sci Eng. 2016;29:125–33.

    Google Scholar 

  27. Ghorbani B, Hamedi MH, Shirmohammadi R, Hamedi M, Mehrpooya M. Exergoeconomic analysis and multi-objective Pareto optimization of the C3MR liquefaction process. Sustain Energy Technol Assess. 2016;17:56–67.

    Google Scholar 

  28. Fahmy MF, Nabih HI. Impact of ambient air temperature and heat load variation on the performance of air-cooled heat exchangers in propane cycles in LNG plants: analytical approach. Energy Convers Manag. 2016;121:22–35.

    CAS  Google Scholar 

  29. Hajji A, Chahartaghi M, Kahani M. Thermodynamic analysis of natural gas liquefaction process with propane pre-cooled mixed refrigerant process (C3MR). Cryogenics. 2019;103:102978.

    CAS  Google Scholar 

  30. Primabudi E, Morosuk T, Tsatsaronis G. Multi-objective optimization of propane pre-cooled mixed refrigerant (C3MR) LNG process. Energy. 2019;185:492–504.

    CAS  Google Scholar 

  31. Song C, Tan S, Qu F, Liu W, Wu Y. Optimization of mixed refrigerant system for LNG processes through graphically reducing exergy destruction of cryogenic heat exchangers. Energy. 2019;168:200–6.

    CAS  Google Scholar 

  32. Hwang JH, Roh MI, Lee KY. Determination of the optimal operating conditions of the dual mixed refrigerant cycle for the LNG FPSO topside liquefaction process. Comput Chem Eng. 2013;49:25–36.

    CAS  Google Scholar 

  33. Wang M, Khalilpour R, Abbas A. Thermodynamic and economic optimization of LNG mixed refrigerant processes. Energy Convers Manag. 2014;88:947–61.

    CAS  Google Scholar 

  34. Khan MS, Karimi IA, Lee M. Evolution and optimization of the dual mixed refrigerant process of natural gas liquefaction. Appl Therm Eng. 2016;96:320–9.

    CAS  Google Scholar 

  35. Jin C, Son H, Lim Y. Optimization and economic analysis of liquefaction processes for offshore units. Appl Therm Eng. 2019;163:114334.

    Google Scholar 

  36. Vikse M, Watson HA, Kim D, Barton PI, Gundersen T. Optimization of a dual mixed refrigerant process using a nonsmooth approach. Energy. 2020;196:116999.

    Google Scholar 

  37. Mehrpooya M, Ansarinasab H. Advanced exergoeconomic analysis of the multistage mixed refrigerant systems. Energy Convers Manag. 2015;103:705–16.

    Google Scholar 

  38. Ding H, Sun H, Sun S, Chen C. Analysis and optimisation of a mixed fluid cascade (MFC) process. Cryogenics. 2017;83:35–49.

    CAS  Google Scholar 

  39. Nawaz A, Qyyum MA, Qadeer K, Khan MS, Ahmad A, Lee S, Lee M. Optimization of mixed fluid cascade LNG process using a multivariate Coggins step-up approach: overall compression power reduction and exergy loss analysis. Int J Refrig. 2019;104:189–200.

    CAS  Google Scholar 

  40. Sun H, Ding DH, He M, Sun SS. Simulation and optimisation of AP-X process in a large-scale LNG plant. J Nat Gas Sci Eng. 2016;32:380–9.

    Google Scholar 

  41. Wang Z, Li Y. Layer pattern thermal design and optimization for multistream plate-fin heat exchangers—a review. Renew Sustain Energy Rev. 2016;53:500–14.

    Google Scholar 

  42. García-Castillo JL, Picón-Núñez M. Design of plate-fin surfaces for multi-fluid heat exchanger applications. Energy. 2019;181:294–306.

    Google Scholar 

  43. Wu J, Ju Y. Design and optimization of natural gas liquefaction process using brazed plate heat exchangers based on the modified single mixed refrigerant process. Energy. 2019;186:115819.

    Google Scholar 

  44. Jamil F, Ali HM. Applications of hybrid nanofluids in different fields. In: Ali H, editor. Hybrid nanofluids for convection heat transfer 2020 (pp. 215–254). Academic Press.

  45. Sriharan G, Harikrishnan S, Ali HM. Experimental investigation on the effectiveness of MHTHS using different metal oxide–based nanofluids. J Therm Anal Calorim. 2020.

  46. Shahsavar A, Ali HM, Mahani RB, Talebizadehsardari P. Numerical study of melting and solidification in a wavy double–pipe latent heat thermal energy storage system. J Therm Anal Calorim. 2020.

  47. Ghaneifar M, Raisi A, Ali HM, Talebizadehsardari P. Mixed convection heat transfer of Al2O3 nanofluid in a horizontal channel subjected with two heat sources. J Therm Anal Calorim. 2020;10:1–4.

    Google Scholar 

  48. Vatani A, Mehrpooya M, Tirandazi B. A novel process configuration for co-production of NGL and LNG with low energy requirement. Chem Eng Process. 2013;63:16–24.

    CAS  Google Scholar 

  49. Khan MS, Chaniago YD, Getu M, Lee M. Energy saving opportunities in integrated NGL/LNG schemes exploiting: thermal-coupling common-utilities and process knowledge. Chem Eng Process. 2014;82:54–64.

    CAS  Google Scholar 

  50. He T, Ju Y. Design and optimization of a novel mixed refrigerant cycle integrated with NGL recovery process for small-scale LNG plant. Ind Eng Chem Res. 2014;53(13):5545–53.

    CAS  Google Scholar 

  51. Mehrpooya M, Hossieni M, Vatani A. Novel LNG-based integrated process configuration alternatives for coproduction of LNG and NGL. Ind Eng Chem Res. 2014;53(45):17705–21.

    CAS  Google Scholar 

  52. Ghorbani B, Hamedi MH, Amidpour M. Development and optimization of an integrated process configuration for natural gas liquefaction (LNG) and natural gas liquids (NGL) recovery with a nitrogen rejection unit (NRU). J Nat Gas Sci Eng. 2016;34:590–603.

    CAS  Google Scholar 

  53. Uwitonze H, Lee I, Hwang KS. Alternatives of integrated processes for coproduction of LNG and NGLs recovery. Chem Eng Process Process Intensif. 2016;107:157–67.

    CAS  Google Scholar 

  54. Jin C, Lim Y. Optimization and economic evaluation of integrated natural gas liquids (NGL) and liquefied natural gas (LNG) processing for lean feed gas. Appl Therm Eng. 2019;149:1265–73.

    Google Scholar 

  55. Ghorbani B, Hamedi MH, Amidpour M, Shirmohammadi R. Implementing absorption refrigeration cycle in lieu of DMR and C3MR cycles in the integrated NGL, LNG and NRU unit. Int J Refrig. 2017;77:20–38.

    CAS  Google Scholar 

  56. Niasar MS, Amidpour M. Conceptual design and exergy analysis of an integrated structure of natural gas liquefaction and production of liquid fuels from natural gas using Fischer–Tropsch synthesis. Cryogenics. 2018;89:29–41.

    CAS  Google Scholar 

  57. Ghorbani B, Mehrpooya M, Shirmohammadi R, Hamedi MH. A comprehensive approach toward utilizing mixed refrigerant and absorption refrigeration systems in an integrated cryogenic refrigeration process. J Clean Prod. 2018;179:495–514.

    CAS  Google Scholar 

  58. Ghorbani B, Shirmohammadi R, Mehrpooya M. A novel energy efficient LNG/NGL recovery process using absorption and mixed refrigerant refrigeration cycles: economic and exergy analyses. Appl Therm Eng. 2018;132:283–95.

    CAS  Google Scholar 

  59. Sabbagh O, Fanaei MA, Arjomand A. Techno-economic evolution of an existing operational NGL plant with adding LNG production part. Oil Gas Sci Technol Revue d’IFP Energ nouvelles. 2020;75:27.

    Google Scholar 

  60. Mehrpooya M, Vatani A, Mousavian SA. Introducing a novel integrated NGL recovery process configuration (with a self-refrigeration system (open–closed cycle)) with minimum energy requirement. Chem Eng Process. 2010;49(4):376–88.

    CAS  Google Scholar 

  61. De Guido G, Lange S, Pellegrini LA. Refrigeration cycles in low-temperature distillation processes for the purification of natural gas. J Nat Gas Sci Eng. 2015;27:887–900.

    Google Scholar 

  62. Sabbagh O, Vahidi Ferdowsi M, Fanaei MA. Reducing energy consumption in gas purification plants (MDEA base) by retrofit design. J Gas Technol. 2017;2:43–49.

  63. Ansarinasab H, Mehrpooya M. Evaluation of novel process configurations for coproduction of LNG and NGL using advanced exergoeconomic analysis. Appl Therm Eng. 2017;115:885–98.

    Google Scholar 

  64. Mehrpooya M, Sharifzadeh MM, Ansarinasab H. Investigation of a novel integrated process configuration for natural gas liquefaction and nitrogen removal by advanced exergoeconomic analysis. Appl Therm Eng. 2018;128:1249–62.

    CAS  Google Scholar 

  65. Sabbagh O, Vahidi Ferdowsi M, Fanaei MA. Prediction of H2S and CO2 solubility in aqueous MDEA and MDEA/PZ solutions using ELECNRTL and ACID GAS packages. J Gas Technol. 2018;3:4–13.

  66. Barekat-Rezaei E, Farzaneh-Gord M, Arjomand A, Jannatabadi M, Ahmadi MH, Yan WM. Thermo-economical evaluation of producing liquefied natural gas and natural gas liquids from flare gases. Energies. 2018;11(7):1868.

    Google Scholar 

  67. Enayatizade H, Chahartaghi M, Hashemian SM, Arjomand A, Ahmadi MH. Techno-economic evaluation of a new CCHP system with a hydrogen production unit. Int J Low-Carbon Technol. 2019;14(2):170–86.

    CAS  Google Scholar 

  68. Arjomand A, Panahi M, Rafiee A. Fischer–Tropsch synthesis in a bottom split reactive dividing wall column. Chem Eng Process Process Intensif. 2020;148:107798.

    CAS  Google Scholar 

  69. EIA, Henry Hub Natural Gas Spot Price. Accessed 16 Nov 2019.

  70. METI, Spot LNG Price Statistics. Accessed 16 Nov 2019.

  71. Jiang H, Zhang S, Jing J, Zhu C. Thermodynamic and economic analysis of ethane recovery processes based on rich gas. Appl Therm Eng. 2019;148:105–19.

    CAS  Google Scholar 

  72. Seider WD, Seader JD, Lewin DR. Product & process design principles: synthesis, analysis and evaluation, (with CD). London: Wiley; 2009.

    Google Scholar 

  73. Bejan A, Tsatsaronis G, Moran MJ. Thermal design and optimization. London: Wiley; 1995.

    Google Scholar 

  74. Vakilabadi MA, Bidi M, Najafi AF, Ahmadi MH. Energy, Exergy analysis and performance evaluation of a vacuum evaporator for solar thermal power plant zero liquid discharge systems. J Therm Anal Calorim. 2020;139(2):1275–90.

    Google Scholar 

  75. Abdollahpour A, Ghasempour R, Kasaeian A, Ahmadi MH. Exergoeconomic analysis and optimization of a transcritical CO2 power cycle driven by solar energy based on nanofluid with liquefied natural gas as its heat sink. J Therm Anal Calorim. 2020;139(1):451–73.

    CAS  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding authors

Correspondence to Mohammad Ali Fanaei or Alireza Arjomand.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.



See Tables 9 and 10.

Table 9 BBD design matrix and the obtained results of the proposed scheme
Table 10 ANOVA for the earning profit of the proposed scheme

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Sabbagh, O., Fanaei, M.A. & Arjomand, A. Optimal design of a novel NGL/LNG integrated scheme: economic and exergetic evaluation. J Therm Anal Calorim 145, 851–866 (2021).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Natural gas
  • Liquefaction
  • Response surface methodology
  • Genetic algorithm
  • Exergy analysis