Upper and Lower Flammability Limits, Limit N2O Concentrations, and Minimum Inerting Concentrations of n-Alkane–N2O–Diluent Mixtures: An Experimental and Computational Study
IF 2.9 Q2 PUBLIC, ENVIRONMENTAL & OCCUPATIONAL HEALTH
{"title":"Upper and Lower Flammability Limits, Limit N2O Concentrations, and Minimum Inerting Concentrations of n-Alkane–N2O–Diluent Mixtures: An Experimental and Computational Study","authors":"Yusuke Koshiba*, and , Shiho Asano, ","doi":"10.1021/acs.chas.3c00023","DOIUrl":null,"url":null,"abstract":"<p ><b>Objectives</b>: N<sub>2</sub>O is widely used in the chemical industry and laboratories; however, several fire/explosion accidents have been reported in facilities that handle N<sub>2</sub>O. This study aimed (i) to experimentally investigate the lower and upper flammability limits (LFL and UFL, respectively), limit nitrous oxide concentration (LN<sub>2</sub>OC), and minimum inerting concentrations (MICs) of fuel–N<sub>2</sub>O–diluent mixtures and (ii) to computationally estimate the UFLs of fuel–N<sub>2</sub>O–diluent mixtures. <b>Methods</b>: Herein, methane and n-propane and nitrogen (N<sub>2</sub>), argon (Ar), and carbon dioxide (CO<sub>2</sub>) were used as fuels and diluents, respectively. The LFL, UFL, LN<sub>2</sub>OC, and MICs of the fuel–N<sub>2</sub>O–diluent mixtures were experimentally determined using a closed cylindrical vessel, and their UFLs were computationally estimated based on the laws of conservation energy and mass and adiabatic flame temperatures. <b>Results</b>: Flammability-limit experiments revealed the following: (i) the LFLs of the CH<sub>4</sub>–N<sub>2</sub>O–diluent and C<sub>3</sub>H<sub>8</sub>–N<sub>2</sub>O–diluent mixtures were 2.5 and 1.4 vol %, respectively, (ii) the UFLs of the CH<sub>4</sub>–N<sub>2</sub>O–diluent and C<sub>3</sub>H<sub>8</sub>–N<sub>2</sub>O–diluent mixtures were 40.5 and 24.0 vol %, respectively, (iii) a nearly linear relationship between the UFL and diluent concentration was found, and (iv) the order of MICs in N<sub>2</sub>O atmosphere was consistent with the inerting ability of the diluents. Calculations based on overall combustion reactions and the laws of energy and mass conservation using six and five chemicals successfully estimated the UFLs of the CH<sub>4</sub>–N<sub>2</sub>O–diluent and C<sub>3</sub>H<sub>8</sub>–N<sub>2</sub>O–diluent mixtures with mean absolute percentage errors of ≤2.8% and ≤4.1%, respectively. <b>Conclusions</b>: The semiempirical model suggested herein allows accurate estimation of the UFLs of the tested fuel–N<sub>2</sub>O–diluent mixtures. These findings would contribute to reducing accident-induced losses in the chemical industry and laboratories handling N<sub>2</sub>O.</p>","PeriodicalId":12,"journal":{"name":"ACS Chemical Health & Safety","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Chemical Health & Safety","FirstCategoryId":"1","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.chas.3c00023","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PUBLIC, ENVIRONMENTAL & OCCUPATIONAL HEALTH","Score":null,"Total":0}
引用次数: 0
Abstract
Objectives: N2O is widely used in the chemical industry and laboratories; however, several fire/explosion accidents have been reported in facilities that handle N2O. This study aimed (i) to experimentally investigate the lower and upper flammability limits (LFL and UFL, respectively), limit nitrous oxide concentration (LN2OC), and minimum inerting concentrations (MICs) of fuel–N2O–diluent mixtures and (ii) to computationally estimate the UFLs of fuel–N2O–diluent mixtures. Methods: Herein, methane and n-propane and nitrogen (N2), argon (Ar), and carbon dioxide (CO2) were used as fuels and diluents, respectively. The LFL, UFL, LN2OC, and MICs of the fuel–N2O–diluent mixtures were experimentally determined using a closed cylindrical vessel, and their UFLs were computationally estimated based on the laws of conservation energy and mass and adiabatic flame temperatures. Results: Flammability-limit experiments revealed the following: (i) the LFLs of the CH4–N2O–diluent and C3H8–N2O–diluent mixtures were 2.5 and 1.4 vol %, respectively, (ii) the UFLs of the CH4–N2O–diluent and C3H8–N2O–diluent mixtures were 40.5 and 24.0 vol %, respectively, (iii) a nearly linear relationship between the UFL and diluent concentration was found, and (iv) the order of MICs in N2O atmosphere was consistent with the inerting ability of the diluents. Calculations based on overall combustion reactions and the laws of energy and mass conservation using six and five chemicals successfully estimated the UFLs of the CH4–N2O–diluent and C3H8–N2O–diluent mixtures with mean absolute percentage errors of ≤2.8% and ≤4.1%, respectively. Conclusions: The semiempirical model suggested herein allows accurate estimation of the UFLs of the tested fuel–N2O–diluent mixtures. These findings would contribute to reducing accident-induced losses in the chemical industry and laboratories handling N2O.
期刊介绍:
The Journal of Chemical Health and Safety focuses on news, information, and ideas relating to issues and advances in chemical health and safety. The Journal of Chemical Health and Safety covers up-to-the minute, in-depth views of safety issues ranging from OSHA and EPA regulations to the safe handling of hazardous waste, from the latest innovations in effective chemical hygiene practices to the courts'' most recent rulings on safety-related lawsuits. The Journal of Chemical Health and Safety presents real-world information that health, safety and environmental professionals and others responsible for the safety of their workplaces can put to use right away, identifying potential and developing safety concerns before they do real harm.