Fast pyrolysis processing of surfactant washed Miscanthus

Miscanthus × giganteus was subjected to pre-treatment with deionised water, hydrochloric acid or Triton X-100 surfactant, and subsequently fast pyrolysed in a fluidised bed reactor at 535 °C to obtain bio-oil. Triton X-100 surfactant was identified as a promising pre-treatment medium for removal of inorganic matter because its physicochemical nature was expected to mobilise inorganic matter in the biomass matrix. The influence of different concentrations of Triton X-100 pre-treatment solutions on the quality of bio-oil produced from fast pyrolysis was studied, as defined by a single phase bio-oil, viscosity index and water content index. The highest concentration of Triton X-100 surfactant produced the best quality bio-oil with high organic yield and low reaction water content. The calculated viscosity index from the accelerated ageing test showed that bio-oil stability improved as the concentration of Triton X-100 increased

Stability and Activity of Doped Transition Metal Zeolites in the Hydrothermal Processing

This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper, and iron under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion-exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds that have an impact on the physical and chemical properties of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts, but their stability and activity under hydrothermal conditions are not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350°C. Catalysts have been characterized before and after treatment using X-ray diffraction, BET physisorption, and scanning transmission electronic microscopy. Metal leaching was determined by the analysis of the water phase following the hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5, for example, molybdenum improves the crystallinity of the zeolite. In general, metal-doped zeolites were relatively stable in subcritical water. The activity of the catalysts for processing lipids, protein, and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella, and Pseudochoricystis ellipsoidea. The catalysts exhibited greater activity toward converting lipids, for example, MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation

Integrated biorefineries: CO2 utilization for maximum biomass conversion

Biomass-derived fuels can contribute to energy sustainability through diversifying energy supply and mitigating carbon emissions. However, the biomass chemistry poses an important challenge, i.e., the effective hydrogen to carbon ratio is significantly lower for biomass compared to petroleum, and biomass conversion technologies produce a large amount of carbon dioxide by-product. Therefore, CO2 capture and utilization will be an indispensable element of future biorefineries. The present research explores the economic feasibility and environmental performance of utilizing CO2 from biomass pyrolysis for biodiesel production via microalgae. The results suggest that it is possible to increase biomass to fuel conversion from 55% to 73%. In addition, if subsidies and fuel taxes are included in the economic analysis, the extra produced fuel can compensate the cost of CO2 utilization, and is competitive with petroleum-derived fuels. Finally, the proposed integrated refinery shows promise as CO2 in the flue gas is reduced from 45% of total input carbon to 6% with another 19% in biomass residue waste streams

Intermediate Pyrolysis of Bambara Groundnut Shell (BGS) in Various Inert Gases (N₂, CO₂, and N₂/CO₂)

Energy from biomass is increasingly gaining attention amidst the environmental challenges of coal and fossil fuels. This study investigated the effects of inert gases (N2, CO2, and N2/CO2) on intermediate pyrolysis and product properties from Bambara Groundnut Shells (BGS) (shells from an underutilized crop, which has high nutritional values). N2/CO2 atmosphere roughly represents flue gas. The results showed that the inert gases did not significantly affect the yields of bio-oil, biochar, and syngas. The pH of bio-oil ranged from 5.2–5.8, indicating the minimum presence of acids in bio-oil. The CHNS analysis showed that all bio-oil and biochar had their carbon content within 50.04–60.49 wt.%. The FESEM resulted in a wide range of pore sizes in biochar produced in an N2/CO2 atmosphere. The GC-MS (Gas Chromatography-Mass Spectrometry) analysis revealed the presence of compounds which can be categorized as alkene, acid, benzene derivatives, ketone, phenol derivatives, alcohol, aldehyde, alkyl, and ester. However, the presence of N2/CO2 gas favored alcohol and phenol production significantly

Utilization of palm oil sludge through pyrolysis for bio-oil and bio-char production

In this study, pyrolysis technique was utilized for converting palm oil sludge to value added materials: bio-oil (liquid fuel) and bio-char (soil amendment). The bio-oil yield obtained was 27.4 ± 1.7 wt.% having a heating value of 22.2 ± 3.7 MJ/kg and a negligible ash content of 0.23 ± 0.01 wt.%. The pH of bio-oil was in alkaline region. The bio-char yielded 49.9 ± 0.3 wt.%, which was further investigated for sorption efficiency by adsorbing metal (Cd2+ ions) from water. The removal efficiency of Cd2+ was 89.4 ± 2%, which was almost similar to the removal efficiency of a commercial activated carbon. The adsorption isotherm was well described by Langmuir model. Therefore, pyrolysis is proved as an efficient tool for palm oil sludge management, where the waste was converted into valuable products