A novel conceptual design by integrating NGL recovery and LNG regasification processes for maximum energy savings

Abstract

Natural gas liquids (NGL) recovery from shale gas needs large amounts of cold energy for cooling, while liquefied natural gas (LNG) re-gasification requires tremendous hot energy for heating. Thus, recycling the cold energy from LNG re-gasification process at a receiving terminal to assist the NGL recovery process has great economic benefits on both energy saving and high-value product recovery. In this paper, a novel conceptual design by integrating NGL recovery from shale gas and LNG re-gasification at receiving terminals has been developed. It firstly generates a process superstructure. Then, a simulation-assisted mixed-integer linear programming (MILP) model is developed and solved for the optimal process synthesis. Next, heat exchange network (HEN) design and analysis are performed to accomplish the maximum energy-saving target. Finally, rigorous plant-wide simulations are conducted to validate the feasibility and capability of the entire conceptual design coupling of separation and heat integration.

Design of an Intermediate Fluid Vaporizer for Liquefied Natural Gas

“…The extraction and utilization of this cold energy has great potential to improve the combined efficiency and to reduce the overall capital and operating costs. Various methods for the LNG cold energy recovery have been proposed, evaluated, and optimized in the literature, including the integration with power generation [54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70], air separation or other low-temperature fractionation [71][72][73][74][75][76], seawater desalination [77,78], agro food deep-freezing and space air conditioning [79][80][81], etc. Utilizing the LNG cold energy for power generation is less influ-enced by the ambient condition, downstream market supply and demand, transportation etc., and attracts the most attention worldwide.…”

Economic Feasibility of Power Generation by Recovering Cold Energy during LNG (Liquefied Natural Gas) Regasification

“…For the production of LNG, NG (post extraction and gas processing) is liquefied using a refrigeration cycle. , At the receiving terminal, regasification or vaporization of LNG is normally achieved using seawater . Although seawater is a free heat source, large volumes are required, and pumping incurs significant electrical energy.…”

“…3,4 At the receiving terminal, regasification or vaporization of LNG is normally achieved using seawater. 5 Although seawater is a free heat source, large volumes are required, and pumping incurs significant electrical energy. Cryogenic LNG is a rich source of cold energy, which is completely wasted when seawater is used for its regasification.…”

Optimal Use of Liquefied Natural Gas (LNG) Cold Energy in Air Separation Units

“…In the terminals, the transported LNG is unloaded from the carriers at a typical flow rate of 12,000 cubic meters per hour and filled in storage tanks. The stored LNG is then pumped to a vaporization system at a pressure between 80 and 120 bar depending on the gas export requirements 1 . After being pressurized, the LNG is converted to gas phase by heat exchange in vaporizers.…”

“…Option 2 in the Supporting Information. With the decision variables 𝐱, the two integration schemes were optimized for the objective function and constraints in Eq(1), where 𝑎 ∈ 𝐻 and 𝑏 ∈ 𝐾.…”