TASK 2: Gas reforming

In the indirect gasification the temperature of the gasifier is only around 750 °C which leads to high concentrations of tar components and light hydrocarbons in the producer gas instead of targeted syngas components (CH4, CO, CO2 and H2). Tar consists of heavy hydrocarbons, like naphthalene, which can also accumulate to pipelines, and can cause clogging and coking in the downstream process units, and therefore it is necessary to process the tar components to lighter molecules.

A catalytic reforming process is typically used for the cleaning of tar and hydrocarbons from the gasification gas. In this task the main research objective is an externally heated steam reformer and especially the following topics:

• comparison of several catalysts in order to find the best suited catalyst for the production of clean syngas for the methane synthesis
• finding the best operation conditions
• investigating the effect of and reasons for the coking phenomenon. 

The typical catalysts in the steam reforming processes are nickel, precious metals and zirconia. There are many commercial versions of these catalysts, and it is also possible to develop a suitable catalyst in the VTT laboratories. VTT has developed gas reforming technology for gasification since the late 80’s, and especially during the UCG and UCGFunda projects new catalysts and reformer concepts have been tested and developed for syngas production. In this project the technology can be upgraded and modified to meet the requirements of the externally heated reformer.

The catalyst testing will be carried out in laboratory and bench scale fixed bed reactors in both atmospheric and pressurized conditions. After optimization of the proper catalyst combination in laboratory, bench scale experiments will be performed to determine the long term stability and the coking resistance of the chosen catalysts.