Fixed-bed gasification process - The case of the heavy metal contaminated energy crops

Energy crops phytoremediation process is one of the techniques used for remediation of contaminated areas. After cleaning soil, contaminated biomass is produce. It should be utilize in the safe way. Among available energy crop conversion technologies, the most suitable seems to be gasification, which gives the possibility of controlling the fate of the extracted HMs. The gasification process of heavy metal contaminated biomass in fixed bed installation has many advantages in comparison to the combustion process. It produces a gaseous fuel, which can be used to produce energy in different types of installations. In the work properties of the heavy metal contaminated (HMC) samples of Miscanthus x giganteus, Sida hermaphrodita and Spartina pectinata was presented. The data were collected from an HMC arable area in Bytom, Upper Silesia, Poland and the former sewage sludge deposit site in Leipzig, Saxony, Germany. The study investigated the impact of different treatments on biomass elemental compositions to determine its suitability for energy production. Both sites were treated as follows: (i) C - Control, no treatment, (ii) treated with standard mineral (NPK) fertilizer (ammonium sulphate and Polifoska - 4 % N, 22 % P₂O₅, 32 % K₂O) applied directly to the soil before planting, (iii) treated with the commercial microbial inoculum Emfarma Plus^® (EFP), ProBiotics Poland. Gasification results shows that the highest values for the Lower Heating Value (LHV) are obtained for an air ratio of 0.18. The highest increment of the LHV is observed for biomass treated by NPK in comparison to control samples.