World Scale Boil-Off Gas Reliquefaction Heinz C. Bauer (speaker), Linde Engineering, Germany Hans Mattsson (speaker), Siemens, Sweden Sven-Erik Brink, Siemens, Germany AIChE Spring Meeting San Antonio, TX April 28 – May 2, 2013 Biographies After graduation at the Technical University Munich as PhD in Applied Physics, Dr Heinz Bauer joined Linde Engineering 32 years ago. He worked in different positions in process design as well as sales and marketing. His focus has been on all kind of cryogenic gas processing including cracked gases, synthesis gas, refinery off-gases and of course natural gas. Presently he is responsible as Vice President for technology of natural gas processing plants. [email protected] Hans Mattsson graduated as Mechanical engineer at Chapman School Karlskrona Sweden 1974. He started in the gas turbine division in what was to become Siemens Industrial Turbomachinery AB, in 1980. He has about 30 years of experience in gas and steam turbine installation, leading different engineering teams. Currently senior technical advisor in the Siemens Energy Oil & Gas, Industrial Power FEED group, for Oil & Gas projects. [email protected] Sven-Erik Brink graduated at the Technical University Brunswick in Mechanical-Engineering with Turbo Machinery as Field of Specialization. He has been with the compressor division of Siemens since 1986 in different positions in sales and marketing working in Germany, Asia Pacific and the US. He has developed the BOG single shaft compressor product line - tandem casing design with variable Inlet Guide Vane Unit (IGV) a heated Dry Gas Seal Carrier. Today he is technical consultant for BOG compressors at Siemens AG, Energy Sector, Oil & Gas, Compressor & Solutions. [email protected] Linde AG Engineering Division 2 CO2 tolerant NRU world scale BOGR Outline Introduction Concept Selection and Optimization Rotating Equipment Conclusion Linde AG Engineering Division 3 CO2 tolerant NRU world scale BOGR Sources of Boil-Off Gas Large LNG export terminals include an LNG tank farm with large LNG tanks providing storage capacity of several hundred thousand meters cubed. Low pressure gases at tank pressure (about 100 to 200 mbarg) originate from several sources like • Boil-off gas caused by heat ingress through the tank walls and LNG pumps • Flash gas generated in the run-down line between liquefaction and storage as well as during cool-down of warm send-out systems • Ship return gas / displacement gas during ship loading Total BOG flow rate for a 10 mtpa facility Linde AG Engineering Division ~1,000 t/d 4 CO2 tolerant NRU world scale BOGR Site Conditions Relevant site parameters • • • • • fuel gas balance capacity of the existing refrigeration systems availability of natural gas as feed stock distance between liquefaction trains and jetty/tank area flare load especially during peak BOG generation BOG reliquefaction (BOGR) will generate a high value product starting from very favorable feed stock conditions, as the absence of water, sour gas components and heavy hydrocarbons in BOG simplifies cryogenic processing significantly Linde AG Engineering Division 5 CO2 tolerant NRU world scale BOGR Outline Introduction Concept Selection and Optimization Rotating Equipment Conclusion Linde AG Engineering Division 6 CO2 tolerant NRU world scale BOGR Concept Selection • a BOGR unit with 0.3 - 1.0 mtpa LNG is similar to a mid-scale LNG plant • most land based plants of this size use SMR technology with ~350 kWh/tLNG or 15 MW for 1000 t/d • feed gas compression to >50 bar requires about the same power as the refrigeration cycle • the preferred cryogenic heat exchangers is a coil wound heat exchanger (CWHE) • the cost adder for a CWHE is more than offset by its superior availability • mechanical drive with gas turbines is the preferred choice • electric motors should be considered, if power supply is reliable and economically attractive Linde AG Engineering Division 7 CO2 tolerant NRU world scale BOGR Process Optimization Base Case — N2 stripper T — LNG subcooler E3 — two casing EFG compressor C3 — unbalanced power between C1 and C2 Linde AG Engineering Division 8 CO2 tolerant NRU world scale BOGR Process Optimization Optimized Case — N2 flash drums D1 & D2 — no LNG sub-cooler required — one casing EFG compressor C3 — balanced power between C1 and C2 Linde AG Engineering Division 9 CO2 tolerant NRU world scale BOGR Open Methane Cycle (DMR concept) mixed refrigerant cooling air cooling Fuel LNG — compression — cooling — 1st expansion — 2nd expansion — recycle Linde AG Engineering Division 10 CO2 tolerant NRU world scale BOGR Fuel Gas Composition Material Balance for N2 — limited amount of N2 in LNG — GT's with high efficiency will see high N2 content in fuel N2 in Fuel Gas (mol%) 50 — max. 8 mol% N2 in BOG are acceptable for state-of-theN2 content art gas turbines in BOG 40 30 8 mol% 6 mol% 20 4 mol% 2 mol% 10 0 25 30 35 40 45 Gas Turbine Efficiency (%) Linde AG Engineering Division 11 CO2 tolerant NRU world scale BOGR Outline Introduction Concept Selection and Optimization Rotating Equipment Conclusion Linde AG Engineering Division 12 CO2 tolerant NRU world scale BOGR N2 Tolerant Gas Turbine SGT-600/700/800 Annular combustor design — premixed air and fuel as main gas — pilot flame burns around main flame for stabilization — 18 3rd generation nozzles (burners) Average residence time in burner mixing tube ~3-5 ms Linde AG Engineering Division 18 burners 13 CO2 tolerant NRU world scale BOGR N2 Tolerant Gas Turbine SGT-600/700/800 Wobbe Index increase by 80% in 2 minutes Operational flexibility 40 30 30 20 20 10 0 10 N2 NOx LFP Load 0 10 Linde AG Engineering Division 20 30 Time [minutes] 40 50 Load [MW] and LFP [% of alarm level] N2 concent [vol%] and NOx [ppm] 40 — DLE system can operate on fuel gas with high inert gas — stable combustion without pulsations with up to 40 vol% N2 — emission performance achieved independent of N2 content 0 14 CO2 tolerant NRU world scale BOGR Boil-Off Gas Compressor (IGV's) Adjustable inlet guide vanes — direct online start-up possible — compact design — large turn-down — low maintenance — plenty of references Linde AG Engineering Division 15 CO2 tolerant NRU world scale BOGR Boil-Off Gas Compressor (Seal Carrier) Heated dry gas seal carrier — avoids thermal shocks (e.g. during start-up) (yellow) Oil heated Seal Carrier (green) Dry Gas Seal — protects from low and high temperatures and from rapid temperature fluctuations — avoids condensate build-up (red) 3D Impeller (blue) Inlet Guide Vane Unit (IGV) Linde AG Engineering Division 16 CO2 tolerant NRU world scale BOGR Outline Introduction Concept Selection and Optimization Rotating Equipment Conclusion Linde AG Engineering Division 17 CO2 tolerant NRU world scale BOGR Marlin Project in Bintulu • World-scale BOG reliquefaction has become reality • Linde Engineering has successfully developed a new product for the LNG industry • Siemens contributed with innovative compressor and gas turbine designs, which are proven in service and are highly respected worldwide • The first plant, which is based on this novel concept, is under execution for Malaysia LNG in Bintulu and is scheduled for start-up in late 2014 Linde AG Engineering Division 18 CO2 tolerant NRU world scale BOGR Thank you for your attention.