Abstract of Special Research Report (SRR-88)
National Institute of Occupational Safety and Health, Japan
Study on Evaluation of Thermal Hazards in ManuFacturing Processes for Reactive Substances.
Introduction
SRR-88-1 |
Shigeru MORISAKI |
: Chemical industries in Japan have begun extensively to produce so-called fine-chemicals such as pharmaceuticals, functional resins, pesticides and so on. The production of these chemicals is usually carried out by a varied and small quantity type process to enhance value of the chemicals. As a result, chemicals with complicated structures have a tendency to be synthesized in a same reaction vessel, and then some different kinds of processes are often used as a multipurpose system for the production of these chemicals. Therefore, the potential hazards of the chemicals including raw materials, intermediates, and finished goods may be increased in connection with unsuitability of installations and difficulty of operation.
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Measurement of Heat of Nitration by a Twin-Type Calorimeter
SRR-88-2 |
Yasuhiro FUJIMOTO |
: In chemical industry in Japan, the production of fine chemicals has been becoming a mainstream in this field. These manufacturing processes involve some serious problems on safety as the production is sometimes carried out with less safety information such as runaway reaction and thermal decomposition. This may be due to the fact that various kinds of chemicals with small quantities are required to produce. |
Evaluation of Runaway Reaction and ThemalExplosion with Adiabatic Calorimetry
SRR-88-3 |
Takayuki ANDO and Shigeru MORISAKI |
: The thermal runaway process is characterized particularly by a progressive increase in heat generation rate, temperature and pressure. It begins when heat generation from particular chemicals undergoing exothermic reaction or decomposition becomes greater than cooling capacity of and/or heat loss from facilities. |
Reproducting Experiment of a Runaway Incident of Nitration Reaction
SRR-88-4 |
Takashi KOTOYORI |
: A reproducing experiment of a runaway incident of a nitration reaction was carried out, in which 5-tert-butyl-m-xylene (hereinafter referred to as BX) was nitrated to 2,4,6-trinitro- 5-tert-butyl-m-xylene (hereinafter referred to as TNBX) in the scale of 1/2,000 amount. |
Runaway Reactions in Benzene Nitration Process in a Bench Scale Batch Reactor
SRR-88-5 |
Toshihiro HAYASHI |
: Runaway reactions in benzene-nitric acid-sulfuric acid system have been studied in a 20 liter batch reactor, in order to make some contributions on the safety of chemical processes dealing with exothermic reactions. The experimental facility, shown in Fig.1, was closely simulated to commercial batch plants. Benzene was agitated under constant temperature (50 °C) in the reactor, and then mixed acid was either fed continuously by a feed pump or thrown rapidly into the reactor by gravitational force. A 61 % nitric acid and a 95 % sulfuric acid were mixed to prepare mixed acids of various contents of both components. Reactants in the reactor were dumped by a relief valve into a blow-down tank filled with water if their temperature exceeded a pre-set value. Temperature-time curve was recorded for each test so as to determine a temperature rise rate, which was an average rate of temperature rise from 50 °C to relief valve activation temperature or the maximum temperature attained. |
Study on the Cause of Distillation Incidents of Chlorinated Aromatic amines
SRR-88-6 |
Takashi KOTOYORI |
: Chlorinated aromatic amines are used as intermediates for synthesis of a variety of medical and pharmaceutical products or agricultural chemicals. Amines of this kind are purified by vacuum distillation after synthesis. |
Case Histories of Accidents in Batch Processes and Analyses
SRR-88-7 |
Yasuhiro FUJIMOTO and Shigeru MORISAKI |
: In this chapter, the case histories of 297 accidents in batch process industories in Japan were classified into several patterns according to their accident types, reaction types, ignition sorces and so on. In particular, the accidents in the reaction or distillation process were examined in detail.
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