Estimation of the heat required for intermediate pyrolysis of biomass

Abstract

Biomass waste contains an abundant source of energy that can be transformed into high-calorific fuel during intermediate pyrolysis, consequently reducing the use of fossil fuel resources. In the present study, medium density fibreboard (MDF), brewery spent grains (BSG) and post-extraction soybean meal (SM) were used to pyrolysis. Valorisation of these wastes via intermediate pyrolysis was carried out at a temperature of 773 K in a fixed-bed reactor under nitrogen atmosphere. The ultimate analysis showed that MDF char has offered the highest carbon content. Generally, chars obtained from these feedstocks were characterized by different internal microstructures. On the one hand, the surface of MDF char has exhibited pores with a regular pattern of small perpendicular blocks. On the other hand, irregular open spaces were detected in BSG and SM chars. The results of this investigation of the microstructure proved that the studied biomass wastes are perspective feedstocks to obtain high-value bioenergy products. Based on the enthalpy balance, it was concluded that the heating value of the pyrolysis gas was higher, the more endothermic pyrolysis process. The research hypothesis confirms that the higher the K2O/CaO ratio in the ash, the better biomass pyrolysis process was catalysed and as a result, less additional heat was required for pyrolysis. To carry out the pyrolysis of MDF, SM and BSG, additional heat input was required in the amount of 2016.8, 1467.9 and 881.1 kJ, respectively. It was found that 4–10% of the higher heating value of the raw materials was missing to achieve the self-sustaining energy of intermediate pyrolysis. Graphical abstract

Inventory Data for the Pyrolysis of Waste Wood

“…Figure a demonstrates that the char yield increased as the ash content of the feedstock increased. The increase in ash content may promote repolymerization reactions and carbon retention in the char Figure b,c illustrates that the char yield increased as the fixed carbon content of the feedstock increased, but it decreased as the volatile matter content increased.…”

“…The increase in ash content may promote repolymerization reactions and carbon retention in the char. 38 Figure 2b,c illustrates that the char yield increased as the fixed carbon content of the feedstock increased, but it decreased as the volatile matter content increased. This is due to the fact that volatiles mainly decompose to produce pyrolysis gas and oil, causing a reduction in char yield.…”

Interactions in co-pyrolysis of Salicornia bigelovii and heavy fuel oil

“…The actual heating rate experienced by the sample was not determined in this study, however, other studies have shown that a biomass sample in this type of setup typically experiences a heating rate of about 100–200 °C min −1 . 45 This heating rate estimation will depend on the properties of the sample such as thermal conductivity, specific heat capacity and density. The gaseous product was not collected in this experiment, as the focus of the study was to understand the effect of interactions on the quality of the co-pyrolysis liquid bio-oil.…”

Review of Hot Topics in the Sustainable Development of Energy, Water, and Environment Systems Conference in 2022

“…Jerzak et al [31] used fiberboard, brewery spent grains, and soybean meal for the pyrolysis process in a fixed-bed reactor at a temperature of 773 K. The results showed a stronger correlation between a more endothermic pyrolysis process and the heating value of the pyrolysis gas, as well as improved biomass pyrolysis when measuring a higher K 2 O/CaO ratio in the ash. It was also found that 4-10% of the higher heating value of the raw materials was lost during the conversion process.…”