Oxidation to spontaneous combustion of pyrophoric iron sulphides in the process industries: A review

In the fossil energy industries, pyrophoric iron sulphides (PISs), the most commonly mentioned pyrophoric material, are widely distributed in the exploitation, transportation, storage, refining equipment and piping of oil and natural gas. When equipment and piping are opened for inspection or maintenance, they may be exposed to air and act as an ignition source by undergoing an exothermic reaction. Accordingly, they become hot or incandescent and can ignite nearby inflammable hydrocarbon-air mixtures. Numerous researchers have performed various research into this area. There are four main interests involved in this regard, and they are listed as follows: (1) the physical and chemical properties of PISs, (2) the suitable condition, processes, and mechanism for oxidation to spontaneous combustion of PISs, (3) the spontaneous combustion risk assessment of PISs, and (4) the active/passive prevention technologies and strategies of spontaneous combustion of PISs. Moreover, the main drawbacks existing in past research are also highlighted. Correspondingly, several solutions are put forward in combination with the current research methods, technology development trends, and industrial practice requirements. By the thorough summary, it is expected to lay a foundation and direct further research into the oxidation to spontaneous combustion of PISs, as well as to better enrich the theoretical basis and technical support for the improvement of production safety management levels in the petroleum, natural gas, and coal chemical industry.