Lignite pyrolysis with subsequent refining of volatile products in separately heated catalytic reactor

  • Lenka JílkováEmail author
  • Karel Ciahotný
  • Jaroslav Kusý
  • Josef Váleš
Original Paper


Among volatile pyrolysis products are organic compounds containing nitrogen, sulfur or oxygen heteroatoms. As a result of this, liquid pyrolysis products in particular become unstable and susceptible to secondary reactions (polymerization, polycondensation, polyaddition), which lead to an increase of average molecular weight or even to the production of solid matter. This paper examines catalytic refining of oxygen, nitrogen and sulfur compounds found in volatile pyrolysis products from Czech lignite, by transformation into water, ammonia and hydrogen sulfide, and acquiring a liquid product suitable for further treatment. The volatile products were refined in gas phase in a separately heated catalytic reactor filled with Ni–W-based hydrocracking catalyst. The main goal of the experiments was to determine the effect of employing a thermo-catalytic reactor on the yielded amounts of individual products, and on the composition of the gaseous and liquid products of lignite pyrolysis. It was found that a higher pyrolysis temperature (650 °C) ensures a sufficient decomposition of pyrolyzed lignite and also a better composition of the gas than a pyrolysis carried out at the temperature of 550 °C. The use of a thermo-catalytic reactor does, on the one hand, results in a decreased yield of the liquid product including its organic phase, but there is an increased yield of light fraction in this organic phase.


Pyrolysis Catalytic pyrolysis Refining Volatile product Lignite 

List of symbols


Ash content in dry sample (%)


Carbon content in dry sample (%)


Hydrogen content in dry sample (%)


Gross calorific value (MJ kg−1)


Net calorific value (MJ kg−1)


Nitrogen content in dry sample (%)


Oxygen content in dry sample (%)


Total sulfur content in dry sample (%)


Content of volatile compounds in dry sample (%)


Water content in analytic sample (%)



Thermal conductivity detector


Compliance with ethical standards

Conflict of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.


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Copyright information

© Institute of Chemistry, Slovak Academy of Sciences 2019

Authors and Affiliations

  1. 1.Department of Gas, Coke and Air ProtectionUniversity of Chemistry and Technology PraguePrague 6Czech Republic
  2. 2.Brown Coal Research InstituteMostCzech Republic

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