Effect of sample preparation on the thermal degradation of metal-added biomass

The present study investigates the effect of different sample preparation methods on the pyrolysis behaviour of metal-added biomass; Willow samples were compared in the presence of two salts of zinc and lead containing sulphate and nitrate anions which were added to the wood samples with three different techniques as dry-mixing, impregnation and ion-exchange. The effect of acid and water wash as common demineralisation pre-treatments were also analysed to evaluate their roles in the thermal degradation of the biomass. Results from thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and pyrolysis-mass spectrometry (Py-MS) measurements indicated that these pre-treatments change the matrix and the physical-chemical properties of wood. Results suggested that these structural changes increase the thermal stability of cellulose during pyrolysis. Sample preparation was also found to be a crucial factor during pyrolysis; different anions of metal salts changed the weight loss rate curves of wood material, which indicates changes in the primary degradation process of the biomass. Results also showed that dry-mixing, impregnation or ion-exchange influence the thermal behaviour of wood in different ways when a chosen metal salt was and added to the wood material

A comparative study on the pyrolysis of metal- and ash-enriched wood and the combustion properties of the gained char

This study aims to investigate the pyrolysis behaviour of metal-contaminated wood and the combustion properties of char derived from wood pyrolysis. Seven metals (Na, Mg, Ca, Zn, Cd, Pb and Fe(III)) were introduced to willow in cation form by ion-exchange and the thermal behaviour of demineralised samples and samples with additional ash were also investigated. The results show that the char yield increased from 21% to 24-28% and levoglucosan yield in vapour phase decreased from 88% to 62-29% after the addition of inorganic compounds, even though the metal binding capacity of wood varied from one metal ion to another. While char yield seems to be effected mainly by the concentration of the metal ions, levoglucosan yield was more dependent on the ionic species especially when sodium ions were present. When combustion experiments were carried out with char made of the metal enriched wood, two consecutive steps were observed, both effected by the presence of inorganic compounds. The first step was identified as the release and combustion of volatiles, while the second peak of the burning profile is the actual combustion of the fixed carbon. The burnout temperatures, estimated ignition indices and the conversion indicate that the type and not the amount of metal ions were the determining factors during the second step of combustion

EN-fuels from solid waste biomass by thermo-catalytic reforming

Intermediate pyrolysis describes a process of converting feedstock by heating it up in the absence of oxygen under moderate, “intermediate” conditions. Typical conditions are a residence time for solids between 5 to 30 minutes, low heating rates and temperatures between 350 °C - 450 °C. Due to these conditions intermediate pyrolysis has remarkable advantages regarding the feedstock, compared to other processes based on flash pyrolysis. Large particles, like pellets or chips can be used. Dry matter content can be below 50% from a technical point of view. For economic reasons the dry matter should be more than 70 % to avoid using energy mainly for drying. However, this dry matter is still very low compared to the requirements of most flash pyrolysis reactors. Another advantage is the use of variable and heterogeneous feedstock, preferably residue and waste biomass. The feedstock can vary from agricultural residues, biogas digestate, municipal and industrial biowaste to sewage sludge. The latest development of the intermediate pyrolysis technology is Fraunhofer UMSICHT´s Thermo-Catalytic Reforming process (TCR®). It is a novel process for the production of char, gas, and bio-oils with improved properties. One significant innovation of TCR® is the integrated downstream catalytic reforming step. This multi-patented technology enables the high quality of the final products carbonisate, syngas, and oil. The robustness of the process permits the utilization of various biogenic feedstocks. The yield of the products depends on the chemical properties of the feedstocks, whereas the quality and characteristics of the products are due the robustness of the process, largely independent of the feedstocks. With the focus on the TCR® oil there is one unique selling point: The oil is thermally stable and therefore distillable. This is the basis for other thermal upgrading processes like e.g. hydro-treatment. Furthermore, the thermal stability of the TCR® oil is a basic prerequisite for usage in the fossil petrol processing industry. This includes, among other applications, combined heat and power (CHP) plants. Additional unique properties are the low water content, the low total acid number, and the high heating value. The high quality of the crude TCR®-oil can be further improved to EN fuel quality by distillation and hydrodeoxygenation (HDO). For hydrodeoxygenation sulfonated NiMo catalyst at temperatures of around 370 °C and a pressures in the range of 140 bar and with LHSV of 0.3 per hour were applied. The resulting products showed full properties of standard hydrocarbon fuels. A separation into diesel and petrol fraction by rectification demonstrated, that both fractions met the fossil fuel standards (EN 228 and EN 590). Through hydrotreating the hydrogen content was increased and the oxygen, sulphur and nitrogen content was significant lowered or respectively removed in an efficient way with a yield over 85 %. Please click Additional Files below to see the full abstract

Thermo-Catalytic Reforming (TCR)–An important link between waste management and renewable fuels as part of the energy transition

The significant progress in energy demands and limited fossil fuel sources, together with environmental concerns, have enforced the study of green, renewable, and sustainable energy sources. Biomass and its residues can be converted into valued fuels and chemicals through advanced thermal conversion technologies. Pyrolysis has been used for a long time for charcoal formation, while intermediate and fast pyrolysis technologies have become of considerable interest in recent years. This substantial interest is because these processes provide different bio-products (synthesis gas, bio-oil and biochar), which can be used directly in numerous applications or as a sustainable energy carrier. This paper investigates an overview of the fundamentals of Thermo-Catalytic Reforming (TCR) technology which is a novel intermediate pyrolysis process combined with a post catalytic reforming unit. This study also identifies the TCR process's features and advantages compared to other pyrolysis technologies, followed by a technical scale unit and the transfer of intermediates in final products. Finally, the treatment of effluents, heat management and implementation of such technologies are discussed. This paper shows how a continuous pyrolysis/reforming plant has been developed and established based on targeted reactor design and in conjunction with preventing major effluent streams, which could have a major impact on the technology's commercial success. Along with two major European projects (To-Syn-Fuel and GreenFlexJET), the TCR technology shall help to overcome the dependency on fossil crude oil and fuels

Risk Factors for Obesity: Further Evidence for Stronger Effects on Overweight Children and Adolescents Compared to Normal-Weight Subjects

Background: We recently showed that in preschoolers risk factors for overweight show stronger associations with BMI in children with high BMI values. However, it is unclear whether these findings might also pertain to adolescents. Methods: We extracted data on 3–10 year-old (n = 7,237) and 11–17 year-old (n = 5,986) children from a representative cross-sectional German health survey (KiGGS) conducted between 2003 and 2006 and calculated quantile regression models for each age group. We used z-scores of children's body mass index (BMI) as outcome variable and maternal BMI, maternal smoking in pregnancy, low parental socioeconomic status, exclusive formula-feeding and high TV viewing time as explanatory variables. Results: In both age groups, the estimated effects of all risk factors except formula-feeding on BMI z-score were greatest for children with the highest BMI z-score. The median BMI z-score of 11–17 year-old children with high TV viewing time, for example, was 0.11 [95% CI: 0.03, 0.19] units higher than the median BMI z-score of teenage children with low TV viewing time. This risk factor was associated with an average difference of 0.18 [0.06, 0.30] units at the 90th percentile of BMI z-score and of 0.20 [0.07, 0.33] units at the 97th percentile. Conclusions: We confirmed that risk factors for childhood overweight are associated with greater shifts in the upper parts of the children's BMI distribution than in the middle and lower parts. These findings pertain also to teenagers and might possibly help to explain the secular shift in the upper BMI percentiles in children and adolescents