Sorption-Enhanced reforming

C-CLEAR is a new idea for electricity production with combined CO₂-capture, and stands for CO₂-free CircuLating Enhanced Autothermal Reforming.

A process is invisaged that takes place in two different fluidised bed reactors. In the first fluidised bed autothermal reforming of hydrocarbons takes place. Autothermal reforming is a combination of steam reforming, which requires energy, and partial oxidation, which provides energy. This reaction is used to produce hydrogen. Amongst others CO₂ is formed by these reactions. The presence of a CO₂-sorbent in the fluidised bed allow for its capture. By removing the CO₂ from the reaction, the adsorbent also changes the equilibrium to promote even more H₂ production than otherwise possible. The hydrogen gas is burned in a gas turbine to produce energy.

In the second fluidised bed reactor the CO₂ is separated from the adsorbent (regeneration). The CO₂ that is released can now be processed further and the adsorbent can be recirculated for re-use in the first fluidised bed reactor.

A special feature of this process compared to other sorption-enhanced technologies is that it can be continuously operated and that all hydrocarbons processed have the chance to take part in CO₂-capture. This is because the heat required to drive the endothermic steam reforming reaction is provided in the reactor itself, instead of externally. External heat production leads inevitably to CO₂ emissions. By separating the adsorption-reaction and desorption reactors (through the use of solid circulation) these individual reactors can be optimised for their specific task, instead of being required to alternate between tasks. The ability to shift the equilibrium conversions by using a sorbent also means that milder conditions can be used to achieve the same performance. The process is a combination of fluidised beds, autothermal reforming and CO₂ capture. All these technologies are used at a large scale in industry, but until now, never together.

The target of this project is to provide a proof-of-principle for C-CLEAR. To accomplish this, not only theoretic studies will be done, but a test setup will be built. In this project ECN and TU-Eindhoven will be closely working together. For certain aspects third parties will be brought in.

C-CLEAR could lower the energy use and the costs of CO₂-reduction for large-scale production of electricity by 30%. Such a technology in the Netherlands could reduce the primary energy penalty for climate free electricity by 9,5PJ compared to available techniques.