In situ Measurements of HCN in a Tube Furnace with Infrared Polarization Spectroscopy

Sun, Zhiwei; FÃ¶rsth, M.; Li, Z.; Li, B.; Alden, M.

doi:10.3801/iafss.fss.10-279

Cited by 5 publications

(4 citation statements)

References 5 publications

(8 reference statements)

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“…Reports of a pioneering study [38,39] on HCN generation from combustion of polyamide 6.6 in the steady state tube furnace provide additional insight into the processes of HCN formation and destruction. In these experiments, infrared polarisation spectroscopy was used to measure the concentration of HCN inside the furnace tube, both close to the flame, and in the cool zone towards the exit of the furnace tube.…”

Section: Correlation Between Radical Reactions and Temperature Dependmentioning

confidence: 99%

The correlation between carbon monoxide and hydrogen cyanide in fire effluents of flame retarded polymers

Molyneux¹,

Stec²,

Hull³

2014

Fire Saf. Sci.

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This study considers the demonstrated correlation between carbon monoxide and hydrogen cyanide in the special case of fire retarded materials. It shows that the combination of aluminium phosphinate and melamine polyphosphate causes a much smaller increase in the carbon monoxide (CO) and hydrogen cyanide (HCN) yields than the combination of brominated polystyrene and antimony oxide, although both fire retardants inhibit combustion reactions in the gas phase. The formation and destruction mechanisms of CO and HCN are considered. It is shown that both toxicants form early in the flame, and that the OH radical is critical for the destruction of both CO and HCN. Crucially, in the context of the flame inhibition mechanism, this suggests that the phosphorus system reduces the H and O radical concentrations without a corresponding decrease in the OH radical concentration, thus it is an effective gas phase flame retardant which only causes a small increase in the toxic product yields. Conversely, the bromine system reduces the H, O and OH concentrations, and thus increases the fire toxicity, by inhibiting decomposition of CO and HCN. Moreover, while the phosphorus flame retardant is effective as an ignition suppressant at low temperatures, this effect-switches off‖ at higher flame temperatures, minimising the potential increase in fire toxicity, once the fire develops.

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Section: Correlation Between Radical Reactions and Temperature Dependmentioning

confidence: 99%

The correlation between carbon monoxide and hydrogen cyanide in fire effluents of flame retarded polymers

Molyneux¹,

Stec²,

Hull³

2014

Fire Saf. Sci.

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show abstract

“…In common with CO, HCN is formed near the base of the flame during combustion of nitrogen-containing materials, 11–13 but is then decomposed in a well-ventilated flame, partly to molecular nitrogen. 14 However, it persists in under-ventilated flames or in the presence of gas phase inhibitors (such as halogenated or organophosphorus flame retardants). 15 It has been detected following burning of fibres, 16 polymers, 17,18 building insulation foams 19 and flexible polyurethane foams.…”

Section: Introductionmentioning

confidence: 99%

“…Methods for the determination of cyanide ions in solution have generally been designed for use in the analysis of soil, water, food, and biological fluids. 23–26 Fire effluent analysis is somewhat different, in that higher HCN concentrations are often encountered, and they occur in a complex mixture of water, organic vapours, and soot particles.…”

Section: Introductionmentioning

confidence: 99%

Quantification of hydrogen cyanide in fire effluent

Hansen-Bruhn,

McKenna,

Hull

2023

Journal of Fire Sciences

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Hydrogen cyanide is often the most toxicologically significant component in fire effluents from nitrogen-containing materials. Unlike the other major asphyxiant, carbon monoxide, sensors for continuous hydrogen cyanide quantification, at and above dangerous concentrations, are not commercially available. This article investigates the analysis of fire effluent captured in bubbler solutions, by colorimetric quantification of hydrogen cyanide using chloramine-T/isonicotinic acid. The bubbler samples were mixed with colorimetric reagents to give a blue dye in response to cyanide ions. A novel reaction scheme accounting for the formation of the blue dye from cyanide ions is presented. Dilute, standard cyanide solutions were found to be stable after storage for up to 1 year. Alkaline bubbler solutions, through which the fire effluent has passed, showed consistent cyanide concentrations, for samples stored between 5°C and 21°C, for up to 31 days after sampling. The effect of other common ions likely to be present in fire effluent solution samples (CO32−, SO32−, SO42−, NO2− and NO3−) was investigated for their potential interference. The most significant interference was sulphite which reduced the apparent cyanide concentration by 13% at 10 mg L−1SO32− concentration.

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“…13 Thermogravimetric analysis–mass spectrometry (TG-MS), thermogravimetry analysis–infrared spectroscopy (TG-FTIR), and pyrolysis gas chromatography–mass spectrometry (GC-MS) are also widely used for gas-phase analyses. Sun et al 14 have spatially and temporally resolved in situ measurements of HCN in a steady-state tube furnace (SSTF) using midinfrared polarization spectroscopy, it was found that high temperatures and good ventilation result in relatively high peak concentrations of HCN inside the tube furnace. Purser and Purser 15 studied the relationships between equivalence ratio and HCN yields in the ISO19700 tube furnace under steady flaming conditions, enabling the relationships between toxic product yields and equivalence ratio to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of toxicity for thermoplastic polyurethane and its flame-retardant composites

Liu

Zong

Chen

et al. 2018

Journal of Thermoplastic Composite Materials

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Toxic product in fire disasters is the most important reason for fire casualties. With wide application of polymer material, the toxic products in fire effluents are getting more and more diversified and complicated. Polyurethane is one of the most widely used materials. In this article, the fire toxicant release has been evaluated for thermoplastic polyurethane (TPU) and its flame-retardant composites. Ammonium polyphosphate (APP), aluminum hydroxide (ATH), and nano-montmorillonite (MMT) were combined into different flame-retardant combinations at certain ratios. Three kinds of flame-retardant combinations (APP-ATH, APP-MMT, and APP-ATH-MMT) were blended to reduce toxicity of TPU. The properties of thermal stability and decomposition were characterized by thermogravimetric analysis (TGA). TGA/infrared spectrometry, static tube furnace, and steady-state tube furnace were used to evaluate the toxic gases, including CO and HCN. Fractional effective dose (FED) was calculated based on the concentrations of CO, CO2, and HCN. The results showed that more than 50% toxicity effect in FED was accounted for HCN. The comprehensive toxicity of TPU was reduced in the samples with APP-ATH and APP-ATH-MMT. The yields of CO, CO2, and O2 consumption were indicated much lower in the samples with APP-ATH-MMT than the other two combinations.

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In situ Measurements of HCN in a Tube Furnace with Infrared Polarization Spectroscopy

Cited by 5 publications

References 5 publications

The correlation between carbon monoxide and hydrogen cyanide in fire effluents of flame retarded polymers

The correlation between carbon monoxide and hydrogen cyanide in fire effluents of flame retarded polymers

Quantification of hydrogen cyanide in fire effluent

Comparative study of toxicity for thermoplastic polyurethane and its flame-retardant composites

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