Fischer-Tropsch technology and deactivation mechanisms
Synthesis gas derived from carbon sources such as natural gas, coal or biomass, can be converted by the Fischer-Tropsch process into liquid hydrocarbons that can be upgraded further to products like synthetic diesel fuel, jet fuel, petrochemical naphtha and base lubricant oils.
The Fischer-Tropsch (FT) process has been known for nearly 100 years and has been applied in several situations when crude oil was a limited or very expensive resource. Now the world oil resources are diminishing and alternative routes to produce fuels and petrochemical derivatives are receiving increased attention. The FT technology provides a route for comparatively cheap natural gas resources to enter the existing high value transportation fuel market.
Several metals may be used as catalysts in the FT process and Co has many advantages compared to Fe, but the relatively high price of Co require careful design and optimization of the catalyst in order to gain commercial advantages. We have therefore chosen to study deactivation processes in detail, a task that is particularly challenging because the particles are encapsulated by long hydrocarbons (wax) during the process.
It is especially demanding to study deactivation in an operating environment. Two doctor theses are focusing on this task.
A major difference between laboratory scale experiments and industrially run reactors is the presence and amount of impurities. Whenever catalysts or reactants are prepared in large batches, impurities are easily introduced to the system. An inGAP project therefore focuses on the effect of various impurities on the FT reaction. Even small (ppm) level of an impurity may have effect on the reaction, and indeed we have seen that the presence of alkali and alkaline earth metals decreases the activity of the reaction.