Review of experimental methods to determine spontaneous combustion susceptibility of coal – Indian context

This paper presents a critical review of the different techniques developed to investigate the susceptibility of coal to spontaneous combustion and fire. These methods may be sub-classified into the two following areas: (1) Basic coal characterisation studies (chemical constituents) and their influence on spontaneous combustion susceptibility. (2) Test methods to assess the susceptibility of a coal sample to spontaneous combustion. This is followed by a critical literature review that summarises previous research with special emphasis given to Indian coals

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

A study of the formation of hydrogen produced during the oxidation of bulk coal under laboratory conditions

A number of studies of the oxidation of coal using The University of Queensland’s two- metre, 62L test rig have been carried out over the past few years. The rig simulates a semi-adiabatic environment radially and allows gas samples to be taken along its length and from the exhaust stream. This enables the generation of a gas and temperature profile across a coal self-heating zone. As the state of spontaneous combustion in underground coal mines is usually inferred from gas samples taken remote to the heatings these laboratory studies offer important insights into the mechanisms of gas formation during coal self-heating events. In particular much emphasis is placed upon the presence of and concentration of any hydrogen. This paper reports the preliminary findings from a test where such gas samples were taken. The bulk of the hydrogen appears to be generated downstream from the hot spot where the coal is at approximately 100°C and there is no free oxygen

Numerical modelling of the self-heating process of a wet porous medium

In this research, the shortcomings of some advanced models for heat and fluid flow and moisture transport within and around a reactive porous medium (a coal stockpile) are numerically investigated based on a local thermal non-equilibrium approach and results are compared with experimental data. A full account of the problem is presented, including transient variation of the maximum temperature in the medium and the time required to vaporize the water content. The former is the main parameter used in the study of spontaneous self-ignition of coal stockpiles and the latter is an indication of the last step of self-heating toward self-ignition. Correlations are developed for the maximum dimensionless temperature inside the pile when the moisture content is near zero and the time that it takes from the beginning of self-heating until this time as functions of porosity, permeability, moisture content and the overall size of the porous medium