Co-pyrolysis of Miscanthus Sacchariflorus and coals: A systematic study on the synergies in thermal decomposition, kinetics and vapour phase products

Abstract

In this work, co-pyrolysis of Miscanthus Sacchariflorus (MS) and three ranks of coal, namely lignite (LC), bituminous coal (BC), and anthracite (AC), was performed at the analytical scale. The co-pyrolysis kinetic and products were analysed and compared theoretically and experimentally. The results revealed the synergistic effects of the coal rank and biomass blend ratio (BBR) on the thermal decomposition and the products in gaseous phase. The co-pyrolysis of MS-LC and MS-BC samples was characterised by three distinct stages, which were sequentially dominated by moisture removal, decomposition of MS, and decomposition of coal. The activation energies of the co-pyrolysis process were different from the activation energies of the pyrolysis of individual MS and coal samples. The kinetics analysis showed that increasing the BBR increased the activation energies of the MS-coal blends up to 25% at the temperatures below 350 °C. However, at the higher temperature range, this decreased the activation energies of MS-LC and MS-BC blends but increased those of MS-AC blends. Both of the coal rank and BBR had noticeable impacts on the thermal behaviour during co-pyrolysis. The optimum positive synergistic effects were obtained on MS-LC blend with a BBR of 1:1. The FTIR analysis results showed the evolution profiles of CH4, CO, CO2, water, formic acid, phenol and xylene. All the products analysed showed L-peaks (250-400 °C) corresponding to MS decomposition. Increasing the BBR promoted the release of all the analysed products from MS-LC and MS-BC, indicating the synergistic effect of the co-pyrolysis.

Kinetic study on the CO2 gasification of biochar derived from Miscanthus at different processing conditions

“…The increasing demand for bioenergy has driven development of the energy crops. Miscanthus is a perennial herb with C4 photosynthesis, which has been considered as one of the most potential renewable energy crop due to its fast growth rate, high yield (the annual output of about 27-44 tons per hectare), high cellulose content (43.1-52.2 wt.%), remarkable adaptability to different environments, disease resistance and low production cost [1,2]. Biochar is the solid product from the pyrolysis of biomass with largely improved characteristics comparing to the raw material in solid fuel application.…”

Steam gasification of Miscanthus derived char: the reaction kinetics and reactivity with correlation to the material composition and microstructure

“…The economic benefit of Miscanthus is believed to be higher than other energy crops, such as sorghum or switchgrass, due to the very high growth rate and low plantation cost. Miscanthus can be planted in poor soils and has no competition with food production [4]. Same to other biomass resources, Miscanthus has low bulk energy density.…”

“…The results showed that the evolution of the gases released was consistent with the weight loss of the samples during the pyrolysis, combustion and gasification processes. Tian et al [4]studied the co-pyrolysis of Miscanthus with coal at various pyrolysis temperatures and identified the synergistic effects of the coal and biomass blending on the thermal decomposition rate and the quality of gaseous products.…”

Application of linear regression algorithm and stochastic gradient descent in a machine‐learning environment for predicting biomass higher heating value

“…It is well established that carbon and hydrogen (which are the main elemental constituents in volatile matter and fixed carbon) contribute significantly to biomass energy content. 7,8 Volatile matter is the vapor phase during biomass degradation 48 whereas fixed carbon is the residual solid after biomass degradation. 49 Both are rich in carbon and hydrogen, which contributes to biomass energy because of their combustive nature.…”