Abstract of Special Research Report (SRR-No.34)
National Institute of Occupational Safety and Health, Japan
A Study on the Prevention of Explosions and Fires for Recycle Industries (Final Report)
Introduction
SRR-No.34-1 |
Takayuki ANDO |
: With the recent promotion of the conservation of energy and resources and reduction of waste, many materials are being recycled. Some aspects of recycling, however, are dangerous, and frequent incidents of explosion, fire, and poisoning have been reported. These hazards are attributed largely to the increase in the amount and types of recycled substances, the replacement of chlorofluorocarbons with liquefied petroleum gas, which is done to protect the ozone layer and to ward off global warming, and the use of flammable cleaning liquids instead of nonflammable ones in an effort to reduce environmental pollution.
This "Final Report" shows the results of this research obtained after the "Midterm Report" published in 2002. |
Methods for Evaluating Reaction Hazards
SRR-No.34-2 |
Yasuhiro FUJIMOTO |
: The disposal of industrial waste materials is potentially hazardous, especially as the blending of recycled chemicals (liquids etc.) is gradually increasing. It is thus possible that unexpected chemical reactions could occur and fires and/or explosions result. One reason leading to this situation would be scarce and/or incorrect information about waste materials; an indication that sufficient safety information can no longer be obtained from literature searches. Methods of screening the blending need to be performed, but these tests must come at a reasonable cost, have good performance, and be easy to carry out because most chemical waste disposal companies are small, are not well capitalized and have few experts available to evaluate safety. Easily-operated and low-cost screening methods for reaction hazards that have reasonable performance are useful for such companies. This research details methods that are easier and lower–cost than a typical high performance reaction calorimeter, the Mettler-Toledo RC1. We also show that these methods are more effective than those carried out in typical waste disposal workplaces where waste chemicals are deposited. Two tests are applied as useful screening methods. The first one is the OmniCal Super-CRC, a commercially available differential reaction calorimeter, while the other is a custom-made differential calorimetry system using a principle similar to that of Super-CRC (labeled as CCS). |
The Investigation of Induction Periods in the Reaction of Hydrogen Peroxide
SRR-No.34-3 |
Mieko KUMASAKI |
: Chemical industries and laboratories have utilized various kinds of chemicals. In disposal process, they are gathered into a waste disposal tank for following disposal treatment such as incineration. The gathering involves risk of unexpected reactions; the waste processes generally proceed without enough care while development and production process require for careful quantitative hazard estimation. |
The Effect of Chemical Structure on the Interaction with Metal Ion in DIsposal Process
SRR-No.34-4 |
Mieko KUMASAKI |
: Some hazardous materials show characteristic features in the reaction with transition metals; they are unstabilized, and sometimes decompose in contact with metal ions. This character may cause severe damages especially in waste disposal process of chemicals. Waste disposal process is less attractive rather than research and development. They sometimes pour chemicals into a waste tank and mix with ones others disposed of beforehand. That may lead unexpected reaction and explosion. The knowledge of the reaction between metal ions - unstable chemicals enable to prevent such disasters as well as thoroughly implementing confirmation of safety. |
A Computational Verification for Deflagration Blast in Open Space
SRR-No.34-5 |
Teruhito OTSUKA |
: When the speed of energy release, such as the flame velocity and expansion speed, is much greater than the ambient sound speed, such as in a high explosive's detonation or a detonation of unconfined vapor, all released energy is concentrated on the shock surface. Therefore, the Sachs' scaling law could well explain the effects in these cases. |
Fire Spred in RDF(Refuse-Deriverd Fuel) Pile
SRR-No.34-6 |
Masaaki YASHIMA |
: The technology of waste handing and resource recycling advances, and RDF or RPF are used as fuel for the incinerator in order to obtain heat energy and electricity energy in Japan. The RDF used in Japan is RDF-5 in ASTM. Fire or explosion is being occurred with the increase in use of the RDF at manufactories or storage facilities. The spreading of combustion zone in the RDF pile is the primary phenomenon in an enlarging fire. The phenomenon is called smoldering. In this study, temperature change in the pile and flame established over the pile were examined in order to explore the fundamental aspect of the spreading fire. In addition, a point to notice in extinguishing the RDF was examined. The RDF sample was piled up to 300 mm using a cylindrical container (inner diameter; 160 mm, height; 350 mm) which consisted of heat insulating material. The cylindrical container was put on a hot plate, and the RDF ignited in the hot surface (bottom). Upward spreading fire is a subject in this study. Considering the effect of the permeability or the natural draft on the spread of fire, the experiment was carried out under next 3 conditions.
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Full-scale Experiment on Dust Explosion Venting
SRR-No.34-7 |
Masaaki YASHIMA |
: The technical recommendation for explosion venting of revised edition, NIIS-TR-NO.38 (2005), was published referring to NFPA 68 (2002) mainly in June, 2005 in NIIS. A full-scale experiment was planed with the purpose of verification of vent area and flame length for dust explosions based on the technical recommendation. In addition, it was planed to obtain a useful knowledge on the protective measure to the circumference. In the experiment, 4 vessels ( 0.2, 1, 6, and 20 m3 ) and wood powder (particle size; 8.8 μm ) were used. In the measurement, the following were examined: internal pressure of the vessel, propagation velocity of the flame in the vessel, velocity of dust cloud ejecting from the vent opening, flame length, sound level. Results are as follows.
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