Flammable Powders Research Articles

Physico-chemical analysis and characterization of the flammability of metallic powders

When fine particles known as flammable powders are suspended in the air under specific circumstances, they have the potential to explode. There could be many serious fatalities, injuries, and structural damage as a result of a dust explosion. By being aware of the flammability parameters and the physico-chemical analysis for flammable powders and taking additional protective measures as a result of the occurrence of these kinds of catastrophic mixes, the risk of such incidents can be decreased. The goal of this study was to determine the flammability characteristics of two combustible powders, magnesium and aluminum powder. These characteristics included the lowest ignition temperature of the dust cloud and dust layer as well as certain physicochemical studies of the composition.

Determination of Fire Parameters of Polyamide 12 Powder for Additive Technologies.

The use of additive technologies keeps growing. Increasingly, flammable powder materials are also used in additive technologies, and there is a risk of explosion or fire when using them. The current article deals with the determination of fire parameters of a powder sample of polyamide Sinterit PA12 Smoth in accordance with the EN 14034 and EN ISO/IEC 80079-20-2 standards. For that purpose, a sample at a median size of 27.5 µm and a humidity of 0% wt. was used. The measurements showed that the maximum explosion pressure of the PA12 polyamide sample was 6.78 bar and the value of the explosion constant Kst was 112.2 bar·m·s−1. It was not possible to determine the MIT value of the settled dust, since the melting point of polyamide sample is low. The MIT of the dispersed dust was 450 °C. Based on the measured results, it can be stated that the powdered polyamide PA12 poses a risk in terms of explosions and fires. Therefore, when using polyamide PA12 in additive technologies, it is necessary to ensure an effective explosion prevention.

Applications of dust explosion hazard and disaster prevention technology

Powdered materials are widely used in industrial processes, chemical processing, and nanoscience. Because most flammable powders and chemicals are not pure substances, their flammability and self-heating characteristics cannot be accurately identified using safety data sheets. Therefore, site staff can easily underestimate the risks they pose. Flammable dust accidents are frequent and force industrial process managers to pay attention to the characteristics of flammable powders and create inherently safer designs.This study verified that although the flammable powders used by petrochemical plants have been tested, some powders have different minimum ignition energies (MIEs) before and after drying, whereas some of the powders are released of flammable gases. These hazard characteristics are usually neglected, leading to the neglect of preventive parameters for fires and explosions, such as dust particle size specified by NFPA-654, MIE, the minimum ignition temperature of the dust cloud, the minimum ignition temperature of the dust layer, and limiting oxygen concentration. Unless these parameters are fully integrated into process hazard analysis and process safety management, the risks cannot be fully identified, and the reliability of process hazard analysis cannot be improved to facilitate the development of appropriate countermeasures. Preventing the underestimation of process risk severity due to the fire and explosion parameters of unknown flammable dusts and overestimation of existing safety measures is crucial for effective accident prevention.

Patient-controlled analgesia for background pain of major burn injury.

Studies have suggested that intravenous patient-controlled analgesia (IV-PCA) can be used safely for the treatment of background pain in burn patients. However, no comprehensive protocols have been published. How patient or surgical factors correlate with the amount of opioid consumption remains unclear. The aim of this study is to provide an IV-PCA protocol for alleviating pain for burn injuries, and to assess factors correlated with opioid consumption. At the Mackay Memorial Hospital, a retrospective analysis from June 27th to October 31st of 2015 was carried out to investigate the use of IV-PCA in relation to the demographic and clinical data of patients who suffered from burn injuries due to a massive explosion of flammable powder. A standardized morphine IV-PCA protocol with rapid escalation was implemented. Variables assessed included age, weight, gender, days of usage, total surface area burned (TBSAB) and operations. Among the 23 patients who received IV-PCA for burn pain control, it was noted that the larger the TBSAB and the higher the visual analogue scale (VAS), the more amount of morphine was consumed. Correlations between morphine consumption positively with weight (P<0.01), female gender (P<0.01), severity of injury (P=0.01), and negatively with receiving operations (P=0.01) were statistically significant. As the daily morphine consumption was positively correlated with TBSAB, VAS, weight, female gender, the use of our IV-PCA protocol was sufficient in the management of background pain for patients with major burn injury.

Protecting Safety During Dust Fires and Dust Explosions - The Example of the Formosa Fun Coast Water Park Accident

This paper will explore the fire and explosion characteristics of cornstarch powder as well as strategies for protecting the safety of people who are involved a dust fire or dust explosion. We discuss the 5 elements of dust explosions and conduct tests to analyze the fire and explosion characteristics of differently colored powders (yellow, golden yellow, pink, purple, orange and green). The results show that, while all of the tested powders were difficult to ignite, low moisture content was associated with significantly greater risks of ignition and flame spread. We found the auto-ignition temperature (AIT) of air-borne cornstarch powder to be between 385°C and 405°C, with yellow-colored cornstarch powder showing the highest AIT and pink-colored cornstarch powder showing the lowest AIT. The volume resistivity of all powder samples was approximately 108 Ω.m, indicating that they were nonconductive. Lighters and cigarettes are effective ignition sources, as their lit temperatures are higher than the AIT of cornstarch powder. In order to better protect the safety of individuals at venues where cornstarch powder is released, explosion control measures such as explosion containment facilities, vents, and explosion suppression and isolation devices should be installed. Furthermore, employees that work at these venues should be better trained in explosion prevention and control measures. We hope this article is a reminder to the public to recognize the fire and explosion characteristics of flammable powders as well as the preventive and control measures for dust explosions.

Minimum ignition energy of mixtures of combustible dusts

Most industrial powder processes handle mixtures of various flammable powders. Consequently, hazard evaluation leads to a reduction of the disaster damage that arises from dust explosions. Determining the minimum ignition energy (MIE) of flammable mixtures is critical for identifying possibility of accidental hazard in industry. The aim of this work is to measure the critical ignition energy of different kinds of pure dusts with various particle sizes as well as mixtures thereof.The results show that even the addition of a modest amount of a highly flammable powder to a less combustible powder has a significant impact on the MIE. The MIE varies considerably when the fraction of the highly flammable powder exceeds 20%. For dust mixtures consisting of combustible dusts, the relationship between the ignition energy of the mixture and the minimum ignition energy of the components follows the so-called harmonic model based upon the volume fraction of the pure dusts in the mixture. This correlation provides results which show satisfactory agreement with the experimental values.

Electrostatic ignition hazards due to pneumatic transport of flammable powders through insulating or dissipative tubes and hoses – New experiments and calculations

Abstract During transportation of powder through pipes or hoses made from insulating materials, electrostatic discharges can occur. To define the resistivity limit of the insulating material for the avoidance of propagating brush discharges, the charging current due to the powder transfer was determined experimentally using different types of hoses and bulk material. The subsequent modeling shows that propagating brush discharges will not occur if such hoses are constructed from dissipative materials or when the resistance measured from the inner surface to the conductive structure of the hose multiplied with the contact area of the electrode is below 4 MΩ m².

Propagating brush discharges in flexible hoses

Propagating brush discharges can occur inside conductive pipework with an insulating liner when pneumatically conveying powders. Flexible plastic hoses with embedded wire spirals are frequently used for pneumatic transfer, but it has not been clear if they have the same problem. This work shows that propagating brush discharges can occur in structures modelling such hoses. Further work is required to establish if mitigating factors are present in actual hoses. Nevertheless, the advice from this work must be that such hoses should not be used for pneumatic transfer of flammable powders unless the plastic is static dissipative or conductive.

Static hazards using flexible intermediate bulk containers for powder handling

AbstractFIBC use is increasing rapidly owing principally to improved handling efficiency and product quality improvement. However, selection of the proper FIBC has many aspects, of which safety is paramount. Numerous accidents have occurred when emptying flammable powders from FIBCs, both with and without flammable vapors additionally present. Owing to the mode of operation and speed of emptying, not only is there a high probability of static generation but also a high probability of one or more operators being in the flash fire zone should ignition occur. Apart from the flash fire produced by a dust cloud and/or flammable vapors displaced from a receiving vessel, a flame may in some cases propagate into the FIBC, which might then explode. This paper discusses the FIBC selection problem, a series of case histories, and available literature. Since no FIBC loading incidents are known, the paper will focus on emptying. In particular it should be appeciated that the potential for operator grounding error and sudden nemesis can be very high.

Guidelines on the electrostatic hazards during pneumatic conveying and storage of flammable powders

Guidelines on the electrostatic hazards during pneumatic conveying and storage of flammable powders