Introducing a novel hybrid system for cogeneration of liquefied natural gas and hot water using ejector-compression cascade refrigeration system (energy, exergy, pinch and sensitivity analyses)

Introducing a novel hybrid system for cogeneration of liquefied natural gas and hot water using ejector-compression cascade refrigeration system (energy, exergy, pinch and sensitivity analyses)

Liquefied natural gas

Organic Rankine cycle

Energy efficiency

Water

Sensitivity analysis

Temperature

Natural gas liquefaction

Exergy

Gas fuel purification

Electric power utilization

Liquefaction of gases

Refrigeration

Rankine cycle

Heat exchangers

Hybrid systems

Ejectors (pumps)

Pinch and exergy analyses

Thermal integration

Two-stage ejector

Multi-component refrigerant compression refrigeration cycles have a high coefficient of performance and difficult controllability. In these systems, it is not easily possible to keep the ratio of stream compositions constant in the event of a leak. Also, due to high power consumption in compression refrigeration cycles, the use of compression-ejector refrigeration systems can reduce energy consumption. In this paper, a novel integrated system for cogeneration of liquefied natural gas (LNG) and hot water using two stages ejector refrigeration system (ERC) and low-temperature organic Rankine cycle (ORC) is developed. The feasibility of using ejector refrigeration systems in the novel integrated structure as the compression refrigeration cycle alternative is investigated. The novel integrated structure produces 38.39 kg/s LNG as the main product and 575.5 kg/s hot water as a byproduct. In the novel integrated structure design, due to the elimination of some equipment in the compression refrigeration systems, high energy consumption is reduced in these units. HYSYS software and MATLAB programming are used to simulate the hybrid system. The specific power consumption and exergy efficiency of the present system are 0.3868 kWh/kg LNG and 36.42%, respectively. The results of exergy analysis illustrate that the most exergy destruction belongs to the heat exchangers, which alone accounts for 60.19% of the total destruction. The heat exchanger network related to each of the multi-stream heat exchangers used in the system is extracted through the pinch method. The sensitivity assessment illustrates that the specific power consumption decreases up to 0.3809 kWh/kg LNG and produced LNG mass flow rate increases up to 39.81 kg/h, respectively when the mole fraction of methane in natural gas increases from 83% to 90%.

196

Applied Thermal Engineering

2021

2021-09-01

Rooholamini, Sajedeh

Ghorbani, Bahram

Ebrahimi, Armin

journalArticle

1359-4311

10.1016/j.applthermaleng.2021.117283

https://www.sciencedirect.com/science/article/pii/S1359431121007195