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Phenyl formaldehyde resins-disaster (case study)

Phenyl formaldehyde resins-disaster (case study)

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Phenyl formaldehyde resins-disaster (case study)

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  1. Phenyl formaldehyde resins-disaster (case study) By SonaliChavan HarshavardhanChaudhari Saurabh Das RohitDeora

  2. Phenyl formaldehyde resins • The reaction of phenol or substituted phenol with an aldehyde, in the presence of an acidic or basic catalyst is used to prepare phenolic resins. • Uses: Phenolic resins are used in adhesives, coatings, and molding compounds. • Heat of reaction: -180 cal/g • Two step process: • Methylolation • Salification

  3. Process description • Reaction in stirred vessel with condensor. • Provision for heating and cooling. • T=60oC, 37% wt. aq. formaldehyde + caustic soda, Phenol in molten state. • Stoichiometric amount of Caustic soda (30% wt. solution) addition over 30 mins at 50oC. • Emergency relief on the reactor is usually provided by rupture disks.

  4. Type of catalyst used, the ratio of reactants, and the reaction conditions determine the molecular structure and physical properties. • Highly exothermic and sensitive to a variety of physical and chemical conditions. • Heat generated by the reaction increases the reaction rate generating more heat. • Reaction rate is typically an exponential function of temperature • Pressure of the system will increase suddenly due to the vigorous evaporation of liquid. • Internal Pressure > Ultimate tensile strength • Thermal runaway !!!

  5. Phenol-Formaldehyde Reaction Incidents at Various Companies

  6. Case study • On September 10, 1997 the Georgia- Pacific Resins plant in Columbus experienced a large explosion in a resin kettle (reactor). • 8,000-gallon batch reactor • The explosion resulted from a runaway reaction in Kettle No. 2. • The reactor’s safety systems failed to contain the rapidly expanding gases

  7. What happened? • An operator charged raw materials and catalyst to the reactor and turned on steam to heat the contents. • A high temperature alarm sounded and the operator turned off the steam. • There was a large, highly energetic explosion. • Separation of the top of the reactor from the shell. • A nearby holding tank was destroyed and another reactor was partially damaged. • Operator killed, 4 injured, 3 firemen burned severely. • Occupational Safety and Health Administration slapped the company with $400000 fine. • Residents within a ¾ mile radius of the facility were evacuated. • People complaining of burning of skin, rashes, sore throat, headaches, breathing problems due to bronchitis, burning of throat, and nausea.

  8. Cause • All the raw materials and catalyst were charged to the reactor at once followed by the addition of heat. • Heat generated exceeded the cooling capacity of the system • Excessive pressure generated by a runaway reaction. • Pressure generated could not be vented through the emergency relief system.

  9. Runaway due to • Accumulation of Formaldehyde • Deviation from process • Poor agitation • Improper heating or cooling

  10. Lessons learned • Thorough hazard assesment • Complete identification of reaction chemistry and thermochemistry • Administrative controls • Temperature control • Addition of raw materials • Emergency relief • Learning from accident history and near misses

  11. Steps To Reduce Hazards • Modify processes to improve inherent safety. • Minimize the potential for human error. • Understand events that may lead to an overpressure and eventually to vessel rupture. • Use lessons learned. • Evaluate Standard Operating Practices. • Evaluate employee training and oversight. • Evaluate the effectiveness of the emergency relief system.

  12. Social Impact Concerns regarding future accidents: • Fear that the GPRI plant will experience another serious accident • The railroad and other plants in the area could also have a chemical accident • Concern that residents wouldn’t even know if an accident takes place (no alarm) • Residents have no information on what to do in the event of an accident (evacuation?) • Concern that a warning will come too late • Concerns about children at school or children being caught in a vapor cloud • Concern for elderly and sick people who may not hear or respond to a warning • When we see fire trucks or hear a loud noise, we don’t know what is going on

  13. Social Impact Concerns regarding air emissions and odors • Reports of chemical smells and/or burning eyes • Experiences with odors, burning eyes, and visual plumes from the plant • Concern about formaldehyde emissions from Georgia Pacific Plant • Awareness that formaldehyde is highly toxic • General concern that air in the area is not healthy • Awareness of other emission sources in area (including large numbers of trucks) • Concern that high rates of asthma and other illness that may be attributable to air emissions • Concern that Ohio EPA doesn’t do enough to reduce air pollution in the area