A Review of Recent Research Results on Soot: The Formation of a Kind of Carbon-Based Material in Flames

Abstract

As a product generated from incomplete combustion, soot is harmful to people’s health and the environment. In recent decades, much attention has been paid to the control of soot generation in combustion systems. Efforts to reduce soot emissions depend on a basic understanding of the physical and chemical pathways from fuel to soot particles in flames. At the same time, flame synthesis method has become an alternative method for the preparation of carbon nanomaterials because of its advantages of low cost and mass production. Carbon-based materials can be synthesized within the sooting zones in flames. The research of soot formation mechanism in flames can provide support for the synthesis of carbon nanomaterials. In this paper, the effects of additives, temperature, and fuel type on soot formation characteristics and soot nanostructure in diffusion flames are reviewed. The deficiencies and prospects are put forward for future research.

A preliminary study on the fire suppression efficacy of a prototype system on hydrocarbon-based diffusion flames

“…It is relevant to note here that, upon heat treatment, the electrolyte will undergo decomposition (except the LiPF 6 fraction) yielding lower aliphatic hydrocarbons—thus, in a way the flame characteristics closely resemble that of laminar diffusion flame of liquid hydrocarbon fuels. 13,20 Therefore, apart from some optional tests, hexane was chosen as the main fuel for further investigations.…”

“…This was followed by two different bespoke tests, using different spray systems, which were carried out (see sections ''Tests on hexane fires with a spray ''gun'' system'' and ''Medium-scale fire tests using an in-house built Venturi spray system''). The salient features of the experimental setup and the efficacies of the various extinguishing agents on diffusion flames of hexane, 20 and optionally on Li-ion electrolyte fires, 13 are given in the latter parts of the ''Results and Discussion'' section. It is relevant to note here that given the inherent variability in the time measurements associated with flaming combustion/extinction experiments, each test was repeated several times and the average over the three closest values are quoted, and the deviations are given as applicable.…”

Soot and charcoal as reservoirs of extracellular DNA

“…There is a great variability in structure and composition of soot and charcoal depending on their source materials and temperature of formation. 12,13 In general, both can be envisaged as polycyclic aromatic materials built from agglomerates of ordered graphitic domains consisting of sp 2 -hybridised carbon and domains that deviate from a perfect graphitic structure with an increased incorporation of oxygen and hydrogen. [14][15][16] An important difference is that the graphitic domains in soot can occur at relatively lower temperatures 13 than charcoal 17 and that charcoal can contain a core of unburnt biomass.…”

Soot and charcoal as reservoirs of extracellular DNA

“…Incomplete combustion of fossil fuels produces soot while burning of vegetation produces both charcoal by pyrolysis and soot by combustion and condensation of gases within fire. There is a great variability in structure and composition of soot and charcoal depending on their source materials and temperature of formation (Schmidt & Noack, 2000;Xi et al, 2021). In general, both can be envisaged as polycyclic aromatic materials built from agglomerates of ordered graphitic domains consisting of sp 2 -hybridised carbon and domains that deviate from a perfect graphitic structure with an increased incorporation of oxygen and hydrogen (Franklin & Randall, 1951;Sadezky et al, 2005;Müller et al, 2007).…”

“…In general, both can be envisaged as polycyclic aromatic materials built from agglomerates of ordered graphitic domains consisting of sp 2 -hybridised carbon and domains that deviate from a perfect graphitic structure with an increased incorporation of oxygen and hydrogen (Franklin & Randall, 1951;Sadezky et al, 2005;Müller et al, 2007). An important difference is that the graphitic domains in soot can occur at relatively lower temperatures (Xi et al, 2021) than charcoal (Pyle et al, 2015) and that charcoal can contain a core of unburnt biomass.…”