• Title/Summary/Keyword: Flammable materials

Search Result 131, Processing Time 0.043 seconds

Detection of H2S Gas with CuO Nanowire Sensor (산화구리 나노선 센서의 황화수소 감지특성)

  • Lee, Dongsuk;Kim, Dojin;Kim, Hyojin
    • Korean Journal of Materials Research
    • /
    • v.25 no.5
    • /
    • pp.238-246
    • /
    • 2015
  • $H_2S$ is a flammable toxic gas that can be produced in plants, mines, and industries and is especially fatal to human body. In this study, CuO nanowire structure with high porosity was fabricated by deposition of copper on highly porous singlewall carbon nanotube (SWCNT) template followed by oxidation. The SWCNT template was formed on alumina substrates by the arc-discharge method. The oxidation temperatures for Cu nanowires were varied from 400 to $800^{\circ}C$. The morphology and sensing properties of the CuO nanowire sensor were characterized by FESEM, Raman spectroscopy, XPS, XRD, and currentvoltage examination. The $H_2S$ gas sensing properties were carried out at different operating temperatures using dry air as the carrier gas. The CuO nanowire structure oxidized at $800^{\circ}C$ showed the highest response at the lowest operating temperature of $150^{\circ}C$. The optimum operating temperature was shifted to higher temperature to $300^{\circ}C$ as the oxidation temperature was lowered. The results were discussed based on the mechanisms of the reaction with ionosorbed oxygen and the CuS formation reaction on the surface.

Improvement Plan for Prevention Regulations to Improve Hazardous Material Safety Management

  • Seongju Oh;Jaewook Lee;Hasung Kong
    • International Journal of Advanced Culture Technology
    • /
    • v.11 no.3
    • /
    • pp.346-357
    • /
    • 2023
  • The purpose of this study is to suggest improvement plans for prevention regulations by reflecting the toxicity, fire and explosion effects of hazardous materials factories and surrounding areas using an off-site consequence assessment program. Regarding the effects of the hydrogen cyanide leak accident, which is the 1st petroleum of the 4th class flammable liquid, Areal Locations of Hazardous Atmospheres (ALOHA) program was used to compare and analyze the extent of damage effects for toxicity, overpressure, and radiation. As a result, the toxicity was analyzed to exceed 5km in the area with Acute exposure guideline level (AEGL)-2 concentration or higher, the overpressure was 103m in the range of 1 psi or more, and the radiant heat was analyzed to be 724m in the range of 2kw/m2 or more. Toxicity and radiation affected the area outside the hazardous material storage area, but the overpressure was limited to the inside of the hazardous material storage area. Therefore, we propose to improve the safety management of hazardous materials by conducting a risk assessment for hazardous materials and reflecting the results in internal and external emergency response plans to prepare prevention regulations.

Preparation of Non-flammable Wiper Paper by Simple H3PO3 Treatment (아인산 처리에 의한 불연성 와이퍼 용지의 제조)

  • Lee, Hong Chan;Lee, Shichoon
    • Journal of Convergence for Information Technology
    • /
    • v.10 no.6
    • /
    • pp.77-86
    • /
    • 2020
  • A thin and porous non-flammable wiper was prepared by phosphorus acid solution treatment and subsequent oven annealing. The H3PO3 treatment improved flame retardancy of wiper paper to nonflammable level. Thermogravimetric analyses showed that residues increased to 50% at 700℃, which means this treatment helps dehydration of the cellulose chain and promotes the formation of char-like structures during the burning. FT-IR and X-ray photoelectron spectroscopy showed that some of the added H3PO3 could react with the functional groups of the cellulose chain. The reacted H3PO3 components promote dehydration of the cellulose components and the formation of a char-like structure and improve the flame retardancy of the wiper paper.

A Study on the Development of Simulating Tool for Evaluation of Electrostatic Discharge (정전기 방전 평가를 위한 간이형 도구 개발에 관한 연구)

  • Choi, Sang-Won
    • Journal of the Korean Society of Safety
    • /
    • v.26 no.3
    • /
    • pp.15-22
    • /
    • 2011
  • Explosion and fire cause about 30 reported industrial major accidents a year by ignition source which discharge of electrostatic generated to flammable gas, vapor, dust and mixtures. It brings economically and humanly very large loss that accident was caused by fire and explosion from electrostatic discharge. Thus, it is very important that electrostatic discharge energy is to be control below not to be igniting flammable mixtures. There are two kinds of analysis model for electrostatic discharge, human body model and machine model. Human body model is available the parameter of human's electrical equivalent that capacitance is 100 pF, resistance is $1.5k{\Omega}$. To simulate and visualize the electrostatic discharge from human body need a very expensive and high voltage simulator. In this paper, we measured the value of capacitance and resistance concerned with test materials and sizing of specimen and the value of charged voltage concerned with test specimen and distance to develop an electrostatic charge/discharge simulating tool for teaching with which concerned industrial employee and students. The result of experiments, we conformed that the minimum ignition energy of methane-oxygen mixtures meets well the equation $W=1/2CV^2$, and found out that the insulating material and sizing of equivalent value having human body mode are the poly ethylene of 200 mm and 300 mm of diameter. Developed electrostatic charge/discharge simulating tool has many merits; simple mechanism, low cost, no need of electric power and so on.

A Study on the Prevention Measures against Fire and Explosion Accidents during Splash Filling in Batch Process (회분식 공정에서 스플래쉬 필링(Splash Filling) 작업으로 인한 화재·폭발 사고 예방대책에 관한 연구)

  • Kim, Sang Ryung;Lee, Dae Jun;Kim, Jung Duk;Kim, Sang Gil;Yang, Won Baek;Rhim, Jong Guk
    • Journal of the Korean Institute of Gas
    • /
    • v.24 no.3
    • /
    • pp.33-39
    • /
    • 2020
  • In general, in a batch reaction process in which products are made using flammable liquids, splash filling is used to clean the walls of the reactor by spraying flammable liquids, which are raw materials used for product, during cleaning of the reactor after work. During this process, mist of flammable liquid is generated, the lower limit of explosion is lowered, and fire·explosion may occur due to discharges caused by various types of complex charges, such as flow charge, collision charge, and ejection charge. Therefore, based on the recent accident case, to identify the risk when working in the form of splash filling with toluene in a batch process and perform an explosion impact analysis using the TNT equivalent method After that, we will analyze the accident results and suggest preventive measures such as constant purge system, improvement of cleaning method, and use of tantalum to prevent such accident.

Study of the Risk of Ignition due to Internal Combustion Engines in Areas with Potentially Explosive Gas Atmospheres (잠재적 폭발위험장소에서 내연기관에 의한 점화 위험성에 관한 연구)

  • Kim, Yun Seok;Rie, Dong Ho
    • Fire Science and Engineering
    • /
    • v.30 no.5
    • /
    • pp.1-8
    • /
    • 2016
  • Safety management in hazardous areas with potentially explosive gas atmospheres (here in after referred to as hazardous areas) in large scale facilities dealing with combustible or flammable materials at home and abroad is very important (significant) for the coexistence of the company and local society based on business continuity management (BCM) and reliance. For the safety management in hazardous areas, two systems are mainly used: (1) the control system for the prevention of combustible or flammable substances and (2) the explosion proof system for the elimination of ignition sources when flammable gases are leaked to inhibit the transition to fire or explosion accidents. While technology and regulations on explosion proof facilities or devices for electrical ignition sources are well developed and defined, those for thermal ignition sources need to be more developed and established. In this study, the internal combustion engine in hazardous areas was investigated to determine the risk of ignition. For this purpose, document searches were conducted on the relevant international standards and accidents cases and risk analysis reports. In addition, this study assessed the application cases of the diesel engine's safety equipment, such as spark arresters regarding the site of process safety management (PSM) system in central Korea. To practically apply these results to the hydrocarbon industry, the safety management method for explosion prevention in hazardous areas was provided by risk identification for ignition sources of internal combustion engines, such as diesel engines.

Synthesis of Boron Nitride Nanotubes via inductively Coupled thermal Plasma process Catalyzed by Solid-state ammonium Chloride

  • Chang, Mi Se;Nam, Young Gyun;Yang, Sangsun;Kim, Kyung Tae;Yu, Ji Hun;Kim, Yong-Jin;Jeong, Jae Won
    • Journal of Powder Materials
    • /
    • v.25 no.2
    • /
    • pp.120-125
    • /
    • 2018
  • Boron nitride nanotubes (BNNTs) are receiving great attention because of their unusual material properties, such as high thermal conductivity, mechanical strength, and electrical resistance. However, high-throughput and high-efficiency synthesis of BNNTs has been hindered due to the high boiling point of boron (${\sim}4000^{\circ}C$) and weak interaction between boron and nitrogen. Although, hydrogen-catalyzed plasma synthesis has shown potential for scalable synthesis of BNNTs, the direct use of $H_2$ gas as a precursor material is not strongly recommended, as it is extremely flammable. In the present study, BNNTs have been synthesized using radio-frequency inductively coupled thermal plasma (RF-ITP) catalyzed by solid-state ammonium chloride ($NH_4Cl$), a safe catalyst materials for BNNT synthesis. Similar to BNNTs synthesized from h-BN (hexagonal boron nitride) + $H_2$, successful fabrication of BNNTs synthesized from $h-BN+NH_4Cl$ is confirmed by their sheet-like properties, FE-SEM images, and XRD analysis. In addition, improved dispersion properties in aqueous solution are found in BNNTs synthesized from $h-BN+NH_4Cl$.

Cycling Performance of Li4Ti5O12 Electrodes in Ionic Liquid-Based Gel Polymer Electrolytes

  • Kim, Jin-Hee;Kang, Yong-Ku;Kim, Dong-Won
    • Bulletin of the Korean Chemical Society
    • /
    • v.33 no.2
    • /
    • pp.608-612
    • /
    • 2012
  • We investigated the cycling behavior of $Li_4Ti_5O_{12}$ electrode in a cross-linked gel polymer electrolyte based on non-flammable ionic liquid consisting of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide and vinylene carbonate. The $Li_4Ti_5O_{12}$ electrodes in ionic liquid-based gel polymer electrolytes exhibited reversible cycling behavior with good capacity retention. Cycling data and electrochemical impedance spectroscopy analyses revealed that the optimum content of the cross-linking agent necessary to ensure both acceptable initial discharge capacity and good capacity retention was about 8 wt %.

A study on the detection of poor contact and arcing fault using a fuzzy logic (퍼지논리를 적용한 전기적 접촉불량 및 아크 검출에 관한 연구)

  • Kim, Hyun-Woo;Kim, In-Tae
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
    • /
    • 2007.11a
    • /
    • pp.205-210
    • /
    • 2007
  • This study on the prevention of electric fire. Generally the electric fire is caused by break or disconnection of the power line, short circuit and poor contact, arcing fault ect. In these causes, this paper is studied on the detection of poor contact and arcing fault. The arcing fault is caused by poor contact mainly. The arcing fault can occurs a electric fire by interaction of flammable gas and materials and it can be caused of tracking and carbonization. These phenomenons is also caused of electric fire. Therefore this paper is studied on the detection of arcing fault and poor contact.

  • PDF

The Influence of Pressure, Temperature, and Addition of CO2 on the Explosion Risk of Propylene used in Industrial Processes

  • Choi, Yu-Jung;Choi, Jae-Wook
    • Korean Chemical Engineering Research
    • /
    • v.58 no.4
    • /
    • pp.610-617
    • /
    • 2020
  • In process installations, chemicals operate at high temperature and high pressure. Propylene is used as a basic raw material for manufacturing synthetic materials in the petrochemical industry; However, it is a flammable substance and explosive in the gaseous state. Thus, caution is needed when handling propylene. To prevent explosions, an inert gas, carbon dioxide, was used and the changes in the extent of explosion due to changes in pressure and oxygen concentration at 25 ℃, 100 ℃, and 200 ℃ were measured. At constant temperature, the increase in explosive pressure and the rates of the explosive pressure were observed to rise as the pressure was augmented. Moreover, as the oxygen concentration decreased, the maximum explosive pressure decreased. At 25 ℃ and oxygen concentration of 21%, as the pressure increased from 1.0 barg to 2.5 bar, the gas deflagration index (Kg) increased significantly from 4.71 barg·m/s to 18.83 barg·m/s.