Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Evaluation of Electric-Turbo-Compounding Technology applied to Marine Diesel-Engines for Waste Heat Recovery

435 views

Published on

Bowman Power and University College London (UCL) presented a new engine efficiency technology at the 14th International Naval Engineering Conference and Exhibition (INEC 2018).

This presentation looks at the rationale behind using ETC technology for shipping and shows the potential uplift that could be achieved when paring a marine engine with the ETC system.  This includes improvements in mechanical power and electric power output.

Published in: Engineering
  • Be the first to comment

Evaluation of Electric-Turbo-Compounding Technology applied to Marine Diesel-Engines for Waste Heat Recovery

  1. 1. Evaluation of Electric-Turbo-Compound applied to Marine Diesel-Engines for Waste Heat Recovery October 4th, 2018 Prof Richard Bucknall (UCL) Presenter: Dr Santiago Suárez de la Fuente (UCL) Dr Shinri Szymko (Bowman Power Group Ltd.) Will Bowers (Bowman Power Group Ltd.) Alastair Sim (Rolls-Royce) Presenter: Keith Douglas (Bowman Power Group Ltd.)
  2. 2. Contents • Introduction • Objectives • Electric-Turbo-Compound (ETC) • Case Study – Frigate • Modelling • Results • Conclusions
  3. 3. Introduction Innovate UK project [101987]: Vessel efficiency at sea, Marine ETC Lead Partner: Bowman Power Group Ltd Partners: Lloyd’s Register, Rolls-Royce and UCL Length: 30 months (between 2015 and 2018) Objectives: • To develop a new, marine-capable ETC system for 4-stroke diesel engines (< 4 MW); • To develop a market study for the new ETC system; • To model the ETC system performance on different ships, layouts and operational profiles; and • To open new development roads for the marine ETC.
  4. 4. Objectives • Model and test different ETC designs for the Frigate’s diesel engines and quantify: • ETC electric power output • Fuel savings • CO2 emission reductions • Secondary impacts  Cylinder backpressure • Initial cost • Payback time What are the benefits and secondary impacts when installing an ETC system on-board a Frigate?
  5. 5. • Exhaust gas, with high temperature and pressure flows from the engine and enters the ETC 1000 • The stationary Nozzle Guide Vanes (NGV) direct and accelerate the flow toward the rotating rotor blades downstream • The flow from the NGV transfers the exhaust energy (high temperature and high pressure) to the turbine blades and rotor • The gases exit the ETC 1000 at close to the exhaust stack • The rotor is connected to the high speed alternator producing a non-stable AC current, which is exported to the Power Electronics unit • This AC input current is converted to DC before final conversion to 3 phase AC grid quality (50/60Hz) output (Can also be used to power site auxiliaries or charge batteries for hybrid solutions) KEY COMPONENTS Turbo Generator Power Electronics 1 2 3 4 5 1 2 3 4 5 6 6
  6. 6. EXAMPLE ETC SYSTEM SET UP 1: TURBO GENERATOR Located downstream of the engine’s turbocharger to recover further energy. Produces electricity typically > 1000 Hz 3: POWER ELECTRONICS The high frequency electricity is converted to grid quality electricity at 50/60 Hz Also available in single system set up 2: TURBOCHARGER To maintain engine performance this is re-matched to work with the turbo generator 2 1 3
  7. 7. ELECTRIC TURBO-COMPOUNDING (ETC) ETC is currently applied: 1 - In-line with the engine’s turbocharger as shown: 1. ETC power is increased by decreasing the TG NGV, thus increasing back pressure on the TC, slowing it and dragging down the air fuel ratio (AFR)  Increased combustion & exhaust temperatures and pumping losses 2. This is offset by decreasing the TC NGV, increasing TC speed and AFR  Further increased pumping losses, residual fraction & firing pressures 1 2 TG & TC NGV’s optimised together to maximise ETC power within engine limits
  8. 8. EFFECT ON ENGINE PERFORMANCE 0 100 200 300 400 500 600 700 Temperature (°C) Engine Baseline System Optimisation 50 150 250 350 450 Pressure(kPa) 1. Increased dP across engine leads to pumping losses. At constant fuel consumption this results in a decrease in engine power 2. Increased engine out pressure results in increased expansion ratio for turbocharging system and more power extracted from exhaust gases  Increased system power Typical pressures and temperatures for ETC application 2 1 2 1 1 2
  9. 9. ELECTRIC TURBO-COMPOUNDING (ETC) ETC is currently applied: 1 - In-line with the engine’s turbocharger as shown: Engine size Fuel Type Typical fuel saving and / or Power uplift Typical ROI payback (months) 0.5 – 2.5MWe Natural Gas 3 – 5% 18 - 30Bio Gas / Low BTU 5 – 7% Diesel 4 – 7%
  10. 10. WASTEGATE VARIANT Engine size Fuel Type Typical fuel saving and / or Power uplift Typical ROI payback (months) 10 - 20MWe Natural Gas 1 – 3 % 24 - 36 ETC is currently applied: 2 - Parallel to the engine’s turbocharger as shown:
  11. 11. OTHER ADVANTAGES Downsizing the engine’s turbo brings through increased AFR at idle, low speeds and loads: • Better transient response and acceleration • Lower transient emissions (NOx and PM) • Reduced Methane slip / UHC emissions (SI gas engines)
  12. 12. Case Study - Frigate • Propulsion layout = CODLOG • Engines = 4 x MTU4000 (20 cylinder each)  16 MW • Electrical Generator Efficiency = 91% • Gas Turbine = 1  36 MW (Out of the scope of this work) • Hotel Demand = 1.9 MWe (Assumed constant) • Fuel (Diesel engines) = F76 (42,700 kJ/kg) [CF = 3.206 t CO2/t of fuel ] [Cost = £392.9/t – average between April 2017 and April 2018] [1]
  13. 13. Case Study - Frigate Power Curve  Assumed a cubic relationship
  14. 14. • Propulsion layout = CODLOG • Engines = 4 x MTU4000 (20 cylinder each)  16 MW • Gas Turbine = 1  36 MW (Out of the scope of this work) • Hotel Demand = 1.9 Mwe (Assumed constant) • Fuel (Diesel engines) = F76 (42,700 kJ/kg) • Maximum Speed Diesel only (kn) = 20.0 • Maximum Speed (kn) = 30.0 • Operational time (days) = 215 (59% of a year) Case Study - Frigate [1]
  15. 15. Case Study - Frigate Operational Profile
  16. 16. Marine Engine Model + ETC aFour-stroke diesel engine
  17. 17. Approach A sensitivity analysis was performed: • ETC Design Expansion Ratios (ER): • 1.1 – 1.7 in steps of 0.2 • 4-stroke diesel engine Design Point (DP): • 75% & 85% MCRe • Operational Point (OP): • 57% to 95% MCRe  9 points • One year operation [2]
  18. 18. Results ETC Electric Power Output (per engine) 18 Larger design ER produce more electrical power. • 680 KWe (ER 1.7) vs 220 kWe (ER 1.1) Higher DP loads produce less electrical power for the same loading condition and ER. • ER 1.7: 680 kWe vs 600 kWe • Better efficiencies and higher ER when the DP is set at 75% MCRe Low design ER do not produce electrical power when: • DP is @ 75% MCRe and OP < 65% MCRe • DP is @ 85% MCRe and OP < 70% MCRe.
  19. 19. Results Pressure before the TC turbine Low DP and ER reduce the backpressure at low loads • Better TC efficiency High ER for any DP can reach a change above 40% at any loading condition (Max. 68% change) • This will be an important issue with respect to NOx formation  Engine recertification may be needed • Exhaust gas leaking to intake manifold  combustion temperature increase
  20. 20. Results Mechanical Power Reduction per Cylinder 20 Drop in mechanical power: • Increase in cylinder backpressure  Pumping losses rise • Lower electrical demand due to ETC operation Larger change happens with larger ER & lower loading at DP and larger OP Larger ETC Power = Larger Mechanical Power Reduction
  21. 21. Results Annual Overall Fuel Savings Frigate annual fuel consumption  680 t (633 t from the 4-stroke & 47 t gas turbine) CO2 emissions  2,180 t (2,030 t from the 4-stroke & 150 t gas turbine) • 60 t of fuel reduced (More than what the GT consumes) • And 190 t of CO2 • And £23,500 • But there is an important increment in backpressure ETC Expansion Ratio (-) Engine Design Point (% MCRe) 1.1 1.3 1.5 1.7 75 2.1% 5.2% 7.3% 8.8% 85 1.0% 4.2% 6.4% 7.9%
  22. 22. Results Initial and Running Costs (Best estimated) • ETC (110 kWe kit) • Specific cost = £700/kWe (Today)  Target 2021 = £350/kWe • Running cost = £0.30/h • Lowest overall cost = £0.39 million (DP 85% MCRe & ER 1.1) • 2 - 110 kWe ETC per engine • Highest overall cost = £1.55 million (DP 75% MCRe & ER 1.7) • 7 - 110 kWe ETC per engine £0.19 million £0.78 million 2021
  23. 23. Results Carbon Emission Reduction Costs •Assuming an operative life of 25 years, reducing CO2 emissions could cost: • DP 85% MCRe & ER 1.1 (Lowest total cost) = £620/t CO2 • DP 85% MCRe & ER 1.5 (Mid total cost) = £190/t CO2 • DP 75% MCRe & ER 1.7 (Highest total cost) = £200/t CO2 [3] £95/t CO2 £100/t CO2 2021 £310/t CO2
  24. 24. Results Payback Time Shortest payback time is 8.4 years  DP 85% MCRe with ER 1.5 • Lower initial cost • Frigate navigates only 59% of the year and the 4-stroke diesel + ETC just 31%
  25. 25. Results Payback Time (Other ships) Ship Type DWT ETC Location Number of ETC per Engine (-) Ship Fuel Savings (%) Payback Time (Years) Coastal Cargo 6,500 ME 1 3.2 3.9 Dry Bulk 96,140 AE 2 7.4 5.2 PSV (Small) 1,315 AE 2 7.3 5.2 PSV (Medium) 4,470 AE 3 5.2 7.5 Passenger (Small) 527 ME 2 3.0 9.0 Passenger (Medium) 5,770 AE 4 5.6 7.1 Tanker 363,280 AE 2 1.2 2.3 Optimum payback time depends on: • Ship utilisation • How the ship is being operated (ETC utilisation) • Complexity
  26. 26. Results Payback Time (Other ships) Ship Type DWT ETC Location Number of ETC per Engine (-) Ship Fuel Savings (%) Payback Time – 2021 Costs (Years) Coastal Cargo 6,500 ME 1 3.2 1.8 Dry Bulk 96,140 AE 2 7.4 2.6 PSV (Small) 1,315 AE 2 7.3 2.6 PSV (Medium) 4,470 AE 3 5.2 3.8 Passenger (Small) 527 ME 2 3.0 4.5 Passenger (Medium) 5,770 AE 4 5.6 3.6 Tanker 363,280 AE 2 1.2 1.2 Optimum payback time depends on: • Ship utilisation • How the ship is being operated (ETC utilisation) • Complexity
  27. 27. Conclusions Performed ETC sensitivity analysis and found that the frigate will benefit from an ETC with a: Design point at 85% MCRe with a design ER of 1.5 • Initial cost of £1.1 million 5-110 kWe ETC per engine • Max. electrical power output per engine (kWe) = 490 • Max. cylinder backpressure change (kPa) = 116 (40%) • Annual fuel savings (t) = 43 (140 t CO2) • Cost CO2 reduction (£/t CO2) = 195 • Payback time (years) = 8.4 • Payback time (years, specific costs 2021) = 4.2 years
  28. 28. Contact Details LinkedIn: https://www.linkedin.com/in/santiagosuarezdlf/ https://www.linkedin.com/in/keith-douglas-9a6772158 Webpage: https://www.bowmanpower.com/ Thank you Any Questions?
  29. 29. Images References 1. https://ukdefencejournal.org.uk/the-type-26-frigate-could-be-the-most- capable-royal-navy-warship-in-decades-if-funded-properly/ 2. https://www.lynda.com/Data-Science-tutorials/least-squares- approach/664827/702911-4.html 3. https://www.conservationinstitute.org/co2-to-ethanol/

×