Thermal hazard assessment

Cronin, J. L., B. F. Noland, and J. A. Barton, "A Strategy for Thermal Hazard Assessment in Batch Chemical Manufacturing," I. Chem. E. Symp. Series, 102, UMIST, Manchester, England (June 1987). 

Analyze existing methodologies for thermal hazard assessment and prevention. 

Cronin, J.L., Nolan. P.F. and Barton. J.A.. 1987. A strategy for thermal hazard assessment in batch chemical manufacturing. Hazards from Pressure, Symposium Series No. 102, 113-122 (IChemE. Rugby. UK),... 

The inq)ortance of thermal hazard assessment to determine safe operating conditions for hazardous reactions. The ability to do these chemistries in-house can dramatically impact timelines. 

Calculation of the Intensity of Thermal Radiation From Large Fires." 1990. First Report of the Major Hazards Assessment Panel, Thermal Radiation Working Group. 

Purser, D.A. "Toxicity Assessment of Combustion Products and Modeling of Toxic and Thermal Hazards in Fire," SFPE Handbook of Fire Protection Engineering, National Fire Protection Association, Quincy, MA, Section 1, 1988, pp. 200-245. 

Gustin, J. L., "Thermal Stability Screening and Reaction Calorimetry—Application to Runaway Hazard Assessment and Process Safety Management," /. Loss Prev. Proc. Ind., 6,275 (1993). 

Detailed Hazard Assessment Low Thermal Inertia (41- factor) Adiabatic Calorimeter A UNDESIRED ATonset ATaDIAB dT/dt dP/dt sadf Tm, tMR estimates Vent sizing data Sample size 100 ml to 1 liter Safe for general laboratory work Good mimic of large-scale runaway Ideal for what-if scenario study... 

The thermal hazards laboratory, in consultation with pilot-plant engineering, typically assess emergency venting scenarios and requirements for runaway reaction hazards. 

A hazard evaluation is performed before assessing the technical feasibility of a new process. Chemical handling/storage criteria, critical process conditions, quality measurements, thermal hazards, and post-campaign cleanup are considered in the introduction of any new process/product. 

Any compd or mixt whose heat of formation is smaller by 500 J/g (or more) than the sum of the heats of formation of its reaction products must be regarded with suspicion and handled with more than usual care. The hazards involved in working with a potentially expl system are directly proportional to the amount and to the rate of energy release. Because the reaction kinetics cannot be predicted, the propensity of a new system for expl reaction must be determined. The sensitivity of the system can be evaluated by means of impact, friction, shock and electrostatic discharge. Appropriate methods are reviewed in the Experimental and Hazard Assessment section of this article. Sensitivity to heat or elevated temp may be evaluated by use of differential thermal analysis (DTA)... 

One of the functions of Global Core Technologies R D is the analytical discipline Reactive Chemicals/ Thermal Analysis/Physical Properties (RC/TA/PP). Some of the capabilities of this discipline are testing and data interpretation for reactive chemicals hazard assessment. It is the responsibility of the owner of any chemical process to use this Dow resource to obtain the information which is necessary to design a safe and efficient operation. Information about the analytical RC Testing discipline including contact names can be obtained on the INTRAnet at Reactive Chemicals/Thermal Analysis/Physical Properties web site. 

Decomposition reactions are often involved in thermal explosions or runaway reactions, in certain cases as a direct cause, in others indirectly as they are triggered by a desired synthesis reaction that goes out of control. A statistical survey from Great Britain [1, 2] revealed that out of 48 runaway reactions, 32 were directly caused by secondary reactions, whereas in the other cases, secondary reactions were probably involved too, but are not explicitly mentioned (Figure 11.1). Therefore, characterizing secondary decomposition reactions is of primary importance when assessing the thermal hazards of a process. 

Thermochemical hazards are only one of many types of potential hazards in chemical processes, but they are of special concern because they are not easily identified and assessed. Even after it is determined that a potential thermal hazard exists, it must be decided whether that hazard can be avoided, controlled, or accepted. Identification of thermochemical hazards becomes even more of a problem when the exact composition of the material being handled, such as a distillation residue, is unknown, or when seemingly unimportant factors, such as catalytic amounts of impurities in starting materials, play an important part in the thermal stability of the process material. 

It is unlikely that a release of flammable fluid could result in a jet fire that would cause an off-site thermal-radiation hazard, and the EPA guidelines [9] do not provide guidance concerning jet-fire hazards assessment. However, the length of a jet flame can be calculated from [7]... 

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