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Mineral insulated heating for fuel cells

A fuel cell is an electrochemical device that produces electricity and heat from a fuel (often hydrogen) and oxygen (usually from the air). Unlike a conventional engine, it does this without burning the fuel and is both cleaner and more efficient. Industries which make use of fuel cell systems are always looking for ways to improve the start-up heating time, especially in applications where the overall starting temperature is low and the operating temperature high. Mineral insulated (MI) heaters and thermocouples offer a cost and energy efficient solution to this challenge. Not only can these heaters significantly accelerate the start up time, but they have the dual function of providing temperature measurement and control. This allows for better temperature regulation and thus an increase in the overall lifespan and durability of the fuel cells.

Kamet’s heating business unit, in partnership with ARi and Okazaki, has a strong focus on innovation and customized solutions for fuel cell applications. We develop and provide mineral insulated heating and mineral insulated temperature measurement solutions for a wide range of fuel cell types. In this regard we are specialists in high temperature fuel cell systems, particularly Solid Oxide Fuel Cells (SOFC) and Molten Carbonate Fuel cells (MCFC).

MI heating for high temperature fuel cell systems (SOFC and MCFC)

Solide Oxide Fuel cell

Solid oxide fuel cells (SOFC)

The high temperatures solid oxide fuel cell (SOFC) operates at temperatures up to 1000°C. It is characterized by the use of a hard solid (ceramic) electrolyte which has been coated with porous electrode materials. The most common oxide combination for the solid electrolyte is a mixture of zirconium and calcium oxide. The solid oxide fuel cell also needs a converter to change the supplied direct current to an alternate current.

Molten Carbonate Fuel cell

Molten Carbonate Fuel cells (MCFC)

The high temperature molten carbonate fuel cell (MCFC) uses carbonate salts as the electrolyte. When heated to 650°C the salts melt and conduct carbonate ions from the cathode to the anode. The hydrogen reacts with the ions resulting in the production of water, carbon dioxide and electrons. These electrons move on an external circuit providing electrical power. Molten carbonate fuel cells are less expensive as they operate well with nickel as a catalyst instead of the more expensive platinum. A further advantage is that their efficiency can go up by 20% to an efficiency rate of 80% when the waste heat is captured and used for cogeneration.

In summary, these two high temperature fuel cell types solid oxide (SOFC) and molten carbon (MCFC) have some advantages in common:

  • their stack size results in a much higher yield of power
  • through cogeneration using the waste heat and/or steam, high overall efficiencies are realized
  • they are not prone to fuel impurities
  • they are flexible in fuel usage
  • due to their high operating temperature there is no need for expensive elements in the catalysts

All these factors work together to make these high temperature fuel cells more reliable and economical at power generation. However, when one adds MI heating systems to them the reliability and efficiency are improved even further due to the acceleration of start-up times and the limiting of shutdowns.

This specific application is a significant breakthrough and fairly new development in the world of MI heating. Kamet is well positioned to play this innovative role due to our years of experience in the high temperature world combined with the expertise and the knowhow of our engineers and the quality of our production partners: ARi Industries and Okazaki.

What makes Kamet’s MI heating elements and thermocouples so suited to high temperature fuel cell systems?

One of our most important products is our expertise. We offer full support for creating bespoke solutions for customers specific fuel cell types as well as advice on how our standard MI heating products can be used for fuel cells in general. Furthermore about the products:

  • flexible and easily integrated
  • can fit intricate shapes
  • easy brazing or soldering
  • interchangeability
  • reliability
    • proven long-life performance at high temperature
    • resistant to the harsh and corrosive environments in which high temperature fuel cells are often used
    • resistant to contamination by moisture and gas due to the use of suitable sheath materials and seals
  • the high temperature rating of our heating products are a perfect match for the temperatures that SOFC’s and MCFC’s operate in (500°C to over 1000°C)
  • their high watt density contribute further to the reduction of start-up times
  • our thermocouples have a fast response and low drift
  • our production partners are experienced in producing MI elements for fuel cell applications in the R&D phase
  • supplied with a 3.1 certificate and a calibration certificate

Some key product parameters

Mineral Insulated (MI) Heaters

When our MI heaters are brazed into the chamber and used for conduction heating, they can achieve 15 W/cm2. In the case of convection heating, the MI Heaterscan achieve up to 4.5 W/cm2, depending on the mass flow rate. Using standard materials an output of 1000°C is possible, and higher if specialized materials are chosen. .

The MI heaters are available in sizes varying from Ø0.5 up to Ø12 and at customized length.

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High temperature thermocouples

Thermocouples

Kamet’s thermocouples are always produced in class 1 or better and are available in duplex, triplex and quadruplex for accuracy and redundancy. We offer a range of insulation, sheath and alloy materials. Each coil is calibrated. Custom made cartridge, plate, radiant, and tubular heaters are offered in all shapes and sizes.

More about High temperature thermocouples

Get in touch

Kamet’s in-house capabilities, expertise and the knowhow of our engineers is complemented by the collaboration with Okazaki and ARi Industries. As such we are able to offer exceptional customer service and advice.
To find out more on heating solutions for your particular (fuel cell) system, please get in touch with us.

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