Stationary MAN B&W MC-S Engines For Biofuel Applications
Contents Abstract...6 Preface...6 The diesel engine and its competitors...7 Diesel engines in stationary applications...7 MAN B&W MC-S engines for biofuel applications...8 Combined heat and power...9 Service experience running on biofuel...12 Conclusion...13 Stationary MAN B&W MC-S Engines For Biofuel Applications 4
Stationary MAN B&W MC-S Engines For Biofuel Applications Abstract In recent years, the stationary diesel engine market has seen a demand for units running on biofuel. The nature of this demand is driven by the desire to be CO 2 neutral, based on reliable, fuelefficient and environmentally friendly power generation for both public utilities and Independent Power Producers (IPPs). This demand is being met by modern marine application derivative medium speed diesel gensets and two-stroke low speed crosshead uniflow diesel engines, capable of burning almost any mineral fuel available on the market, whether liquid or gaseous. Engine output P mech (kw) 80,000 70,000 60,000 50,000 40,000 30,000 20,000 10,000 0 100 Fig. 1: Engine programme MAN B&W Two-stroke Low speed 200 300 400 MAN Four-stroke Medium speed 500 600 700 Engine speed (r/min) This paper deals with the application scenarios of such engines and their biofuel capability and describes the installation examples of such engines. China HHM 1980 DMD 1980 YMD 1989 CMD 2007 STX 2007 JAD 2007 ZJCME 2008 ZZD 2008 RPM 2008 Yungpu 2008 CMD 2011 Croatia Uljanik 1954 Split 1967 Korea Hyundai 1976 Doosan 1983 STX 1984 Japan Mitsui 1926 Makita 1981 Hitachi 1951 Kawasaki 1923 Poland Cegielski 1959 Diesel engines for power generation from MAN Diesel & Turbo are offered in the categories shown in Fig. 1. MAN high speed and medium speed engines from MAN Diesel & Turbo s companies in Germany, Denmark and France range from 0.5 MW to 22 MW per unit. MAN B&W two-stroke low speed diesel engines of the MC-S type are designed by MAN Diesel & Turbo, Copenhagen, Denmark. These are available in unit sizes of up to 80 MW. The engines are built by MAN Diesel & Turbo licensees listed in Fig. 2. Russia Bryansk 1959 Fig. 2: MAN Diesel & Turbo two stroke licensee family Vietnam Vinashin 2004 The low speed two-stroke engine matches any requirement of medium to large size projects, whether for island utilities, large IPP or captive plants, say up to 250-300 MW. Preface Stationary MAN B&W MC-S Engines For Biofuel Applications 6
Low speed engines are particularly suited to digest difficult fuels at a high efficiency and good reliability. Engineers are well-acquainted with the technology through wide experience from the world merchant fleet, which is dominated by MAN B&W low speed two-stroke engines. The diesel engine and its competitors Looking at the prime mover options available to the end user today and comparing their efficiencies, Fig. 3 shows the relevant range of 12-80 MW per unit. It is undisputed that the twostroke diesel engine is unrivalled as the most fuel efficient prime mover whether compared with medium speed engines, steam turbines or single cycle or combined cycle gas turbines. Thermal efficiencies % 65 60 55 50 45 40 35 30 25 Low speed diesel engine Medium speed diesel engine Gas turbine 20 1 5 10 50 100 Fig. 3: Power efficiency comparison at ISO 3046 Biofuel Specifications Low speed diesel engine in combined cycle Combined cycle gas turbine Steam turbine 500 Unit capacity (MW) Diesel engines in stationary applications MAN B&W low speed diesel engines are always matched to the actual climatic conditions of the site with due allowances for seasonal variations as well as to the variation in the calorific value of the fuel. Derating for two-stroke low speed diesel engines is therefore not relevant as an acceptable combustion chamber heat load is maintained by the matching. Biodiesel Vegetable oil Treated vegetable oil Crude vegetable oil Animal fat Frying fat Table 1 Comparable to diesel Lower pour point (rape seed oil, soybean oil) High pour point of 30-50 C (palm oil, palm stearin) Low acid and low ash content High acid content (palm oil) and/or High gum content (soybean oil) High pour point High acid content when untreated High pour point May have high acid content May contain polymers 7 Stationary MAN B&W MC-S Engines For Biofuel Applications
MAN B&W MC-S engines for biofuel applications The MC-S engine family has been on the market since 1982. In the early years of the new century, a number of requests were received for possible use of a variety of biofuels which are available in the market, see Table 1. Based on experience with the medium speed engines, one of the evaluation criterion was the Total Acid Number (TAN). High acidity will lead to corrosion of the fuel equipment. Modified components: Larger fuel valves introduced Larger fuel pumps introduced; modified materials In 2006, the first testing on biofuel for two-stroke low speed diesel engines was carried out on a one cylinder test stand in Denmark. The test was carried out with tallow with a TAN of 40. Based on the results of these tests, design changes were made with respect to the size of the fuel oil pump (increased for low calorific valve variants) and material selection, see Fig. 4. The guiding biofuel oil specification was established allowing the TAN to be 25, see Table 2. Reinforced camshaft introduced Fig. 4: Conversion of a standard stationary HFO engine to a biofuel engine Stationary MAN B&W MC-S Engines For Biofuel Applications 8
In recent years, we have seen a variety of biofuel specifications and we have made a list of the most prevailing specifications, see Table 3. In 2007, H. Cegielski - Poznan S.A. obtained an order for a MAN B&W two-stroke low speed diesel engine for the engine type 7L35MC-S running on crude palm oil with a TAN of 14 at Brake Power Plant in Germany. Apart from the design changes of the fuel oil system on the engine, it was determined that the external biofuel system should be made of stainless steel, or other corrossion resistant material, see Fig. 5. All other recommendations for the remaining systems, i.e. lube oil, cooling water, starting air and exhaust gas remain unchanged. Guiding Biofuel Specification 1) Designation Density at 15 C kg/m 3 1010 Kinematic viscosity at 100 C 2) cst 55 Flash point ºC >_ 6 0 Carbon residue % (m/m) 22 Ash % (m/m) 0.15 Water % (m/m) 1.0 Sulphur 3) % (m/m) 5.0 Vanadium ppm (m/m) 600 Aluminium + Silicon mg/kg 80 Sodium plus potassium ppm (m/m) 200 Calcium ppm (m/m) 200 Lead ppm (m/m) 10 TAN (Total Acid Number) mg KOH/g 4) < 25 SAN (Strong Acid Number) mg KOH/g 0 1) Maximum values valid at inlet to centrifuge plant 2) Pre-heating down to 15 cst at engine inlet flange is to be ensured 3) Lodine, phosphorus and sulphur content according to agreement with emission controls maker 4) TBO of engine fuel systems to be adjusted according to actual value and experience Table 2 Biofuel Specifications Test Method Unit 1 2 3 4 TAN mgkoh/g 14 12 12 25 Conradson carbon residue ASTM D 189 % wt 0.5 2 0.52 0.74 Water by distillation (*) ASTM D 95 % vol 0.5 <1 0.11 0.1 Flash point, PMcc ASTM D 93 C 200 >60 239 - Phosphorus ISO 10478 mg/kg 100-15 - Total Acid Number Din/EN-ISO 660 mg/ KOH/g 14 17 11.2 24.96 Calorific value, net ASTM D 4868 MJ/kg 36 37-39 36.9 35.5 Density at 15 C (*) ASTM D 4052 g/ml 930 kg/m3 0,89-0,92 0.8888 0.9142 Viscosity at 50 C ASTM D 445 cst 32 40 28.3 28 Sulphur IP 336 ppm 10 <50 1 - Ash ASTM D 482 % wt 0.01 <0.1 <0.01 0.005 Table 3 9 Stationary MAN B&W MC-S Engines For Biofuel Applications
Biofuel service tank Start up service tank To biofuel service or setting tank All pipes and tanks to be made from stainless steel or other corrosion resistant material Fig. 5: Fuel oil system, one engine Electrical energy TCS unit A) Power turbine Exhaust gas energy Turbo generator A) Steam boiler Process steam Desalination B) Heat exchanger District heating Process heating (230-290 C) Pressurised process heat District heating Desalination Process water District heating Air cooler energy A) Hot water B) Hot water (80-130 C) Energy from lubricating oil cooling A) Heat exchanger (60-65 C) Energy from jacket cooling A) Heat exchanger B) Direct use (80-85 C) Turbo generator Process steam District heating Fig. 6: Waste heat recovery Stationary MAN B&W MC-S Engines For Biofuel Applications 10
Combined heat and power 30 C Ambient Temp. Emergency Cooler (Radiator) 609 kw LT circuit Engine LO to LO from Lube Oil Cooler (Radiator) 418 kw Often, customers require utilisation of the waste heat from the two-stroke low speed diesel engine. As can be seen from Fig. 6, the waste heat can be used for a variety of heating purposes. Fresh Water From 12 C Well (regular operation) In case of failure in regular operation 2 nd stage Air Cooler (Radiator) 609 kw Plate Heat Exchanger Feed Water Pre Heating The Brake Power Plant is not only producing power for the grid but is also supplying heat to the palm oil refinery for the refining processes, see Fig. 7. Optional Plate Heat Exchanger Emergency cooler Radiator Exhaust Gas Heat Exchanger, 2 nd Stage For engines 7K60MC-S which will be installed in the UK, the waste heat will be used for expanding natural gas, see Fig. 8. Generator cooler Using the heat from two-stroke low speed diesel engines requires a special design of the scavenge air cooler and Engine to from Jacket Water Cooler 704 kw HT circuit 1 st Stage Air Cooler 1050 kw 7 bar(g) Steam from Steam Network Heat Exchanger High Temperature Water Network this has presented added benefit to the customers as it is possible to optimise the scavenge air cooler in order to extract as much heat from the engine as possible. Condensate 30 C Ambient Temp. High Temp.System Cooler (Radiator) 1754 kw High Temperature Water Network Fig. 7: Waste energy utilisation 11 Stationary MAN B&W MC-S Engines For Biofuel Applications
Electricity ~ 14.100 kw e MAN B&W 7K60MC-S Fig. 8: Combined heat and intelligent power (CHiP) Service experience running on biofuel The engine running at the Brake Power Plant has reached 6,000 running hours and we have supervised this plant in order to collect practical experience with operation on biofuel. Apart from the need to adjust the cylinder oil composition the sulphur-free palm oil, we are satisfied with the inspection results of the engine components in the fuel oil system, see Fig. 9. Due to the use of virtually sulphur-free palm oil, the Brake engine runs satisfactorily with a NO x reducing SCR catalyst downstream of the turbocharger exhaust gas turbine. Fig. 9: Fuel oil plunger at 5,855 running hours Stationary MAN B&W MC-S Engines For Biofuel Applications 12
Conclusion MAN B&W MC-S engines are applicable anywhere when fuel-efficient, reliable and flexible power production is required. Besides traditional fuels such as heavy fuel and marine diesel oil, biofuel can be applied. The future development of such engine will be dictated by the market, in particular by the future environmental regulations and biofuel qualities. 13 Stationary MAN B&W MC-S Engines For Biofuel Applications
All data provided in this document is non-binding. This data serves informational purposes only and is especially not guaranteed in any way. Depending on the subsequent specific individual projects, the relevant data may be subject to changes and will be assessed and determined individually for each project. This will depend on the particular characteristics of each individual project, especially specific site and operational conditions. Copyright MAN Diesel & Turbo. 5510-0098-01ppr Oct 2014 Printed in Denmark MAN Diesel & Turbo Teglholmsgade 41 2450 Copenhagen SV, Denmark Phone +45 33 85 11 00 Fax +45 33 85 10 30 info-cph@mandieselturbo.com www.mandieselturbo.com MAN Diesel & Turbo a member of the MAN Group