SMX® Ocean AIP STRUCTURE
At the 27th of October 2014 the French Industrial Group Direction des Constructions Navales & Service (DCNS) announced a concept of a new Conventional AIP submarine – SMX® Ocean. The boat was represented on the first day of the 24th International Naval Defense & Maritime Exhibition & Conference “EURONAVAL 2014”in Le Bourget (France). The new conventional submarine concept SMX® Ocean opens the new generation of convention AIP submarines. Drastic alterations had undergone an AIP system of SMX® Ocean that is one of the main parts of submarine propulsion system. In accordance with DCNS’s announcement, this system is based on a new concept as well. New AIP concept attracted interest of many visitors of exhibition. In our brief presentation we shall speak about new AIP concept only.
WHAT INNOVATIONS PROVIDE NEW POSSIBILITIES OF SMX® Ocean?
New SMX® Ocean submarine (concept) contain many different innovations. In current presentation we shall discuss innovations regarding to the SMX® Ocean submarine Air Independent Propulsion system only. First, the SMX® Ocean submarine has layout and dimensions of hull the same as the French nuclear powered submarine SSN Barracuda (Suffren class). Such decision accepted for conventional (diesel powered) submarine had created favorable conditions for increasing total and submerged endurance of boat. Submarine SMX® Ocean with submerged displacement 5300 tons will be the biggest conventional boat in the world. Second, it had been announced that the SMX® Ocean submarine will operate one week submerged with average speed 14 knots. It is serious enough announcement. To provide such performance, the propulsion system has to have power up to 1.8MWe during whole operation time. Third, it is a new generation of AIP system. In accordance with announcement of DCNS, the new submarine will be fitted with integrated AIP which comprises two powered fuel cells and diesel fuel reformer for onboard hydrogen production instead of traditional MESMA (closed cycle steam turbine) AIP system.
PEMFC IS POSSIBLE COMPONENT OF SMX® Ocean AIP
We can state that PEMFC as a type of fuel cell in marine power systems widely used. From early 2000s PEMFC type of fuel cell dominates in majority of marine projects. In particular, PEMFCs are applied successfully in German conventional AIP submarines SSK Type 212/212A (U31-U36) and Type 214. Pure hydrogen as fuel and LOX as oxidizer is used in PEMFCs of these boats . Hydrogen is stored in metal-hydride-filled vessels. PEMFC stacks Metal hydride tanks LOX vessel
GERMAN SSK FUEL CELL AIP SUBMARINES TYPE 212/212A, TYPE 214
The Type 212 (U31-U36) is being constructed by Howaldtswerke-Deutsche Werft GmbH (HDW) of Kiel and Thyssen Nordseewerke GmbH (TNSW) of Emden. (HDW is responsible for the bow sections and TNSW for the stern section.). The Type 214 submarine is derived from the Type 212, as an export variant it lacks some of the classified technologies of its smaller predecessor (Type212) U212 Dimensions Length 56m; Beam 7m; Beam 7m; Draught 6m Displacement (surfaced) 1,450t Displacement (submerged) 1,830t U212 Performance Speed (surfaced) 12kt Speed (submerged) 20kt AIP SINAVYCIS PEMFC BZM34 (9x34kW=306kW) Range (at 8kt surfaced) 8,000 miles Range (at 8kt submerged) 420 miles Maximum Dive Depth 700m+ U214 Dimensions Length 64m; Beam 6.3 m; Draft 6.0m; Height 13m Displacement (surfaced) 1,690t Displacement (submerged) 1,860t U214 Performance Submerged Patrol Speed of Advance 6kt Range 12,000nm AIP SINAVYCIS PEMFC BZM120 (2x120kW=240kW) Mission Endurance 12 weeks Constantly submerged three weeks without snorkelling Mission Sprint Speed 15kt to 20kt Maximum Dive Depth 400m+ Comprehensive analysis of possible variants of integrated AIP system for French submarine SMX® Ocean (Concept) in analytic report Bakst A.–Submarine SMX® Ocean Concept AIP Structure is represented. Report’s Table of Contents
2. SMX® Ocean SUBMARINE HULL DIMENSIONS
3. SMX® Ocean SUBMARINE CONCEPT GOALS
4. SMX® Ocean AIP STRUCTURE
5. ANALYSIS OF SMX® Ocean AIP COMPONENTS
6. SMX® Ocean SUBMARINE AIP PERFORMANCE CALCULATION
ONLINE OF CURRENT PRESENTATION
1. Submarine SMX® Ocean Integrated AIP System Features 2. Marine Diesel Fuel for Integrated AIP Systems; 3. Integrated Diesel fuel Reforming – PEMFC; 4. PEMFC Characterization;
5. Integrated Diesel fuel Reforming – SOFC;
6. SOFC Characterization;
Presentation contains two parts: DFATR-PEMFC The Probable AIP Structure of Submarine SMX® Ocean. Part1. DFATR-SOFC The Supposed AIP Structure of Submarine SMX® Ocean (concept) Part2. Pictures, graphs, layouts and diagrams used in the presentation are intended for text illustration only.
MARINE DIESEL FUELS
Reformer Input Fuel, Oxygen, Water Reformer Output Hydrogen Pure Hydrogen cannot be produced from diesel fuel by reforming. SR, POX, and ATR produce so-called “Syngas” Water Gas Shift Reaction Real Reformer Output is a mixture: H2, CO, CO2, H2O, CH4, C.
AIP SYSTEM CHALENGES
Pure HYDROGEN is used as a fuel in Proton Exchange Membrane Fuel Cells (PEMFC) and Phosphoric Acid Fuel Cells (PAFC).
AIP SYSTEM CHALENGES
1. To obtain pure HYDROGEN from diesel fuel, then Carbon monoxide, Carbon dioxide, Water, Methane, Carbon and Sulfur have to be removed from reformer products. 2. Reformer products has temperature > 600°C. They have to be cooled till 80°C-100°C if they will be used in PEMFC. To obtain pure HYDROGEN the reforming reactor has to be fitted with following additional equipment: – High temperature Water-Gas-Shift Reactor; – Low temperature Water-Gas-Shift Reactor; – Pressure Swing Absorber; – Heat Exchanger.
DIESEL-FUEL AUTOTHEMPERMAL REFORMER – PEMFC
STARTUP OF DIESEL FUEL REFORMER
In submarine applications, a fast startup reformer is essential requirement in a battle situation. Together with it, a submarine has enough power sources to provide diving and move silent underwater during some days without using AIP. It seems, this time is enough to startup AIP system and recharge battery. Nevertheless, the fast startup of reformer is the very important parameter of integrated AIP system. To start up diesel-fuel reformer we have to obtain high temperature fuel-vapor and water-steam. Operating temperature of reformer >700C. Preheating of water and fuel takes time. What reasons compel to provide fast startup of AIP reformer? It is noise. Turbulent combustion and water boiling are accompanied with noise. Noise discloses submarine.
DIESEL FUEL AUTOTHEMPERMAL REFORMING NOISE
Fuel cells have no moving parts and combustion and therefore they are much silent than many different technologies. This characteristic allows to use fuel cells in submarines. German SSK submarines Type 212 and Type 214 have AIP containing nine and two PEMFC stacks installed respectively. The diagram below illustrates, most conversation takes place around a noise level of 60 dBa, which is approximately the noise level measured at 1 meter for all fuel cell units between 1-250 kW regardless of application. Source: http://www.fuelcells.org/base.cgim?template=benefits
DIESEL FUEL AUTO-THEMPERMAL REFORMING NOISE
Usually fuel cells is integrated with source of fuel cell’s fuel and oxygen. German SSK submarines Type 212 and Type 214 storage hydrogen and oxygen onboard. Hydrogen is stored in containers with metal hydrides and oxygen – in LOX vessels. Such system guaranties very low level of noise. Reformers application for production of hydrogen increase level of noise. Integrated into a system together with fuel cell, a combustion chamber, a boiler, fuel and oxygen pumps and/or fans that are typically needed, which are usually sources of noise on submarine AIP. SSK fuel cell AIP Submarine Type 212/212A SSK fuel cell AIP Submarine Type 214
SIMPLIFIED DIAGRAMS OF PEMFC
PEMFC contains polymer electrolyte membrane, gas diffusion electrodes with platinum catalyst layers, carbon sheets and bipolar plates on each side. http://bioage.typepad.com/.shared/image.html?/photos/uncategorized/ sofc_and_pem_1.png
NAFION Nafion (sulfonated tetfluoroethylene based fluoropolymer-copolymer) is the first of a class of synthetic polymers with ionic properties which are called ionomers. Nafion’s unique ionic properties are a result of incorporating perfluorovinyl ether groups terminated with sulfonate groups onto a tetrafluoroethylene (Teflon) backbone. Nafion has received a considerable amount of attention as a proton conductor for proton exchange membrane (PEM) fuel cells because of its excellent thermal and mechanical stability. The chemical basis of Nafion’s superior conductive properties remain a focus of research. Protons on the SO3H (sulfonic acid) groups “hop” from one acid site to another. Pores allow movement of cations but the membranes do not conduct anions or electrons. Nafion can be manufactured with various cationic conductivities. Normal Nafion will dehydrate (thus lose proton conductivity) when temperature is above ~80 °C. This limitation troubles the design of fuel cells, because higher temperatures are desirable for a better efficiency and CO tolerance of the platinum catalyst. Silica and zirconium phosphate can be incorporated into Nafion water channels through in situ chemical reactions to increase the working temperature to above 100 °C. Source: NAFION http://en.wikipedia.org/wiki/Nafion
PEMFC MODIFIED ELECTROLYTES
Nafion–silica composite membranes as electrolytes for PEFCs Nafion–mesoporous zirconium phosphate composite membranes as electrolytes for PEFCs Source: Nafion and modified-Nafion membranes for polymer electrolyte fuel cells: An overview http://www.ias.ac.in/matersci/bmsjun2009/285.pdf
One of the main parts of PEMFC is the membrane electrode assembly (MEA). The MEA of a single PEM fuel cell is shown in figure. The MEA is typically sandwiched by two flow field plates that are often mirrored to make a bipolar plate when cells are stacked in series for greater voltages. The MEA consists of a proton exchange membrane (PM), catalyst layers (CL), mocro-porous layer (MPL) and gas diffusion layers (GDL). Typically, these components are fabricated individually and then pressed to together at high temperatures and pressures
SIVANYCISPEM Fuel Cell BZM34 and BZM120 PERFORMANCES
To evaluate possibility of PEMFC application as a key-component of submarine AIP system we tried to carry out an analysis of tests results of existing PEMFC stacks. For this aim we had selected SIVANYCISPEM Fuel Cell BZM34 and BZM120 that had been used in AIP German SSK submarines Type 212 and Type 214. SIVANYCISPEM Fuel Cell BZM34 and BZM120 had been worked out, constructed, manufactured, developed, and tested by SIEMENS Company. PEMFC optimization is the key direction to obtain effective fuel power convertor for submarine AIP fuel cell.
SIVANYCISPEM Fuel Cell BZM34 and BZM120
Components of SIVANYCISPEM Fuel Cell BZM34 SIVANYCISPEM Fuel Cell BZM120 Source: http://www.industry.usa.siemens.com/verticals/us/en/marine-shipbuilding/brochures/ Documents/SINAVY-PEM-Fuel-Cell-en.pdf
SIEMENS PEMFC BZM34 AND BZM120 EFFICIENCY
PEMFC TARGETS FOR SUBMARINE AIP APPLICATION
Stack Specification Based on Application Requirements Design of a Stack for Submarine AIP Applications as an Example Stack design appropriate for submarine AIP requirements and operating conditions: · Power density (kW/l) – target > 2kW/l · Specific power (kW/kg) – target > 2kW/kg · Nominal load (typical): 800 kW · Area specific power density: 1W/cm² · Single cell voltage target: 670mV · Stack design · 300 cm² active area · 300 cells Challenge: Reduction of cell pitch.