Effect of Pyrolysis Reactions on Coal and Biomass Gasification Process

Abstract

Thermodynamic analysis of a gasification process was conducted assuming that it is composed of two successive stages, namely: pyrolysis reaction followed by a stage of gasification reaction. This approach allows formulation the models of selected gasification processes dominating in industrial applications namely: Shell (coal), SES (coal), and DFB (dual fluid bed, biomass) gasification. It was shown that the enthalpy of fuel formation is essential for the correctness of computed results. The specific computational formula for a wide range of fuels enthalpy of formation was developed. The following categories were evaluated in terms of energy balance: total reaction enthalpy of gasification process, enthalpy of pyrolysis reaction, enthalpy of gasification reaction, heat demand for pyrolysis reaction, and heat demand for gasification reactions. The discussion of heat demand for particular stages of gasification related to the various processes was performed concluding the importance of the pyrolysis stage.

Simulation of the Steam Gasification of Japanese Waste Wood in an Indirectly Heated Downdraft Reactor Using PRO/II™: Numerical Comparison of Stoichiometric and Kinetic Models

“…Figure 2 presents the flowsheet topology of the gasification mechanism reported in Section 2 and shows the designs following similar studies from Chmielniak et al [42] and Nikoo et al [43]. Simulation nodes have rhombus shapes and represent the streams of the components.…”

Pyrolysis characteristics and microstructure evolution of different coal types

“…Coal pyrolysis is a complex process in which a series of physical and chemical reactions occur at different temperatures when coal is heated in isolated air or inert atmosphere. Its reaction is very rapid, producing gas(The gases are mainly low molecular compounds such as CH 4 , H 2 and CO), liquid and solid products, generally starting at 300°C and ending at 900°C (Wiatowski et al 2016, Peng et al 2016, Li et al 2021, Chmielniak et al 2021). The increase of temperature, volatile decomposition and intermolecular fracture during pyrolysis will change the pore structure and permeability of coal (Self et al 2012, Bhaskaran et al 2015, Meng et al 2020, Yu et al 2021, Wang et al 2021), it will not only affect the escape of gas in the pyrolysis process, but also affect the transportation of gasifying agent in the subsequent gasification process.…”