Dr Xuesong Zheng – Process Integration Ltd (PIL) UoM Novel LNG Process Dr Xuesong Zheng – Process Integration Ltd (PIL)

Outline LNG process review Introduction to the UoM LNG process Case study for performance comparison Single Mixed Refrigerant (SMR) process UoM LNG process

LNG Process Review Natural Gas Liquefaction During the natural gas liquefaction process, a large amount of shaftpower is required to run the refrigerant compressors. Shaftpower consumption is an important performance indicator of the refrigeration process.

LNG Process Review Existing Liquefaction Technologies Propane Pre-cooled Mixed Refrigerant (C3/MR) Process Most efficient, but very complicated configuration Optimised Cascade Cycles Three pure refrigerant cycles in cascade Double Mixed Refrigerant Cycles Two mixed refrigerant cycles in cascade Mixed Fluid Cascade Process Three mixed refrigerant cycles in cascade Single Mixed Refrigerant (SMR) Process Simplest configuration, but lower efficiency Complicated Efficient

LNG Process Review SMR Process Low efficiency Evaporation at a single pressure level Simplest structure Small number of design variables Easy to optimise Low efficiency

LNG Process Review A novel LNG process was developed at the University of Manchester to: Strike the balance on process complexity and energy efficiency A single MR cycle with more operating variables Simple structure but improved energy efficiency SMR C3/MR UoM Complexity Efficiency

Process outline (i) The Novel UoM LNG Process: Product streams from the flash unit are allocated to actual refrigerant streams with different flow ratio. Light refrigerant (LR) is pre-cooled to a lower temperature. Heavy refrigerant (HR) is compressed from the intermediate pressure level. LR HR

Process outline (ii) Improved efficiency Compared with SMR, the UoM LNG process achieves: More operating variables within a single MR cycle. More flexible operation with flow rate allocation of LR and HR refrigerant streams. LR and HR refrigerant streams have different composition, which is favourable for T-H profile matching in the cold box. LR and HR evaporate at different pressure levels, which is favourable for T-H profile matching in the cold box. Only part of the refrigerant (LR) is compressed from the low pressure end to the high pressure end. Improved efficiency

Performance comparison (i) LNG processes: Single MR Cycle UoM novel LNG process Natural gas cooling profile 210 ton LNG /day

Performance comparison (ii) Design Basis: Physical property package: EOS Peng-Robinson Minimum approach temperature: 3 oC Temperature after ambient cooling: 35 oC Compressor isentropic efficiency: 78% Pump isentropic efficiency: 75% Objective for optimisation: minimise shaft power

Design Scenario - 65 Bar Single MR cycle Shaft power demand: 2390 kW Min. approach temperature: 2.6 oC

Design Scenario - 65 Bar Single MR cycle Shaft power demand: 2390 kW Min. approach temperature: 2.6 oC

Design Scenario - 65 Bar UoM novel LNG process Shaft power demand: 2259 kW Min. approach temperature: 2.62 oC

Design Scenario - 65 Bar UoM novel LNG process Shaft power demand: 2259 kW Min. approach temperature: 2.62 oC

Design Scenario - 65 Bar UoM novel LNG process Shaft power demand: 2259 kW Min. approach temperature: 2.62 oC

Shaft Power Demand (kW) All Design Scenarios Energy performance comparison Feed Pressure (Bar) Shaft Power Demand (kW) Relative reduction SMR process UoM LNG process 40 2818 2599 7.77% 65 2390 2259 5.48% 100 2084 1924 7.68% Shaft power demand Energy Savings

All Design Scenarios Energy performance comparison For 1.0 MTPA LNG production Feed Pressure (Bar) Shaft Power Demand (MW) Savings SMR process UoM LNG process Shaft Power (MW) Operating Cost (MM$/yr) 40 37.8 34.9 2.9 1.75 65 32.1 30.3 1.8 1.05 100 28.0 25.8 2.1 1.28 Annual operating hours: 8520 Power cost: 0.07 $/kWh

Conclusions The UoM LNG process is a simple mixed refrigerant process. The energy efficiency of the UoM process is 5% - 8% higher than the SMR process. The UoM process saves operating costs for LNG production. (By 1.0 MM$/yr - 1.75 MM$/yr for each MTPA LNG production) The economic benefits are more significant if the energy savings are utilised to increase LNG production.

Contact details Mike Murray - IP Asset Ventures Simon Clarke - UMIP  +44 (0)7934 623490  Michael.Murray@ipasset.com Simon Clarke - UMIP  +44 (0)161 306 8510  Simon.Clarke@umip.com Xuesong Zheng – Process Integration Ltd  +44 (0)161 918 6789  Xuesong.Zheng@processint.com