Experimental studies on spalling characteristics of Indian lignite coal in context of underground coal gasification

Deployment of Underground Coal Gasification in India

“…It is important to estimate spalling rates under different operating conditions in order to identify and quantify the influence that spalling phenomena has on the process. Experimental methods for characterizing spalling of coal have been developed in micro UCG scale, along with model based insights into the development of the reactor zone 42 . The IITB group has carried out experimental measurements of cavity formation and development of different operating conditions in micro-UCG.…”

A process model for underground coal gasification – Part-II growth of outflow channel

“…This process model has been used to explain experimental observation during UCG experiments performed earlier to determine spalling effects and criteria 15 . For the comparison with lab-scale experiments, the process model developed in this work was appropriately downscaled to the shape and size of the spalling apparatus and the simulations were performed at experimental operating and observed spalling conditions.…”

“…These experiments were performed on a spalling apparatus which mimics the flow conditions in actual outflow channel. More details of these experiments and the results can be found elsewhere 15 . Figure 9 shows that the proposed model is able to predict the product gas calorific values as well as Simulations were also performed at different spalling rates and the average calorific values of product gas at different rates of spalling were observed.…”

Pyrolysis characteristics and microstructure evolution of different coal types

“…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. Therefore, it is of great theoretical and practical significance to study the gasification products and pore size changes of coal char in the process of coal pyrolysis to realize safe, efficient, and clean utilization of coal.…”