A solid substance known as “popcorn” polymer is under study as the potential cause of the initial explosion in November 2019 that devastated the TPC Group operation in Port Neches, Texas, the Chemical Safety Board reports.
The CSB released a recent update on their ongoing investigation into the emergency that wrecked the facility and damaged homes and businesses in the surrounding community, resulting in an evacuation order on Thanksgiving Eve. Total property damage has been estimated at $500 million.
According to the report, the initial blast followed a “loss of containment” in a fractionating column in the facility’s South Unit where 1,3-butdiene, used in the production of synthetic rubber, was manufactured. A column is used to separate or fractionate flammable liquids into component parts or fractions of varying volatility.
Approximately 6,000 gallons of liquid rapidly drained from the column, immediately vaporizing into a volatile cloud that ignited as a massive explosion. That explosion heavily damaged piping and equipment, triggering more fires and explosions.
CSB investigator suspect a pipe rupture caused by popcorn polymer as causing the loss of containment.
“Popcorn” polymer can form in process vessels containing a high concentration of butadiene. It is a hard, porous, opaque material created when oxygen reacts with butadiene in various areas of a butadiene production plant.
High internal strain inside the popcorn polymer chains cause them to rupture and form new polymer seeds, increasing the total volume of popcorn polymer as the process repeats. This large increase in volume can produce enough pressure to swell or crack steel equipment.
Buildup of popcorn polymer has long been recognized as causing equipment ruptures in industry. Popcorn polymer was known to form in the South Unit before the incident.
However, CSB has not confirmed the pipe rupture due to extensive damage and unstable structural conditions at the site.
TPC subsequently transitioned into a terminal and services operation while evaluating rebuilding the facility.
CSB is continuing to conduct its investigation. At its conclusion, a final report will be issued.