Lessons from Harvey - III

PART - I 

PART - II

Revisiting plant inventory

Many chemical plants, especially those built in the last millennium, carry far too much inventory. This excess baggage harks back to the pre-computer and pre-Internet era when supply chain management practices, as we know them today, were not prevalent. Online procurement now has done away with time consuming paperwork and approvals. RFID tracking of shipment has reduced uncertainties. Logistics planning, optimised shipping methods and routes, synergy with suppliers etc helps the industry to prune down the inventory. Inventory reduction not only brings down the operating expenses significantly, but is a giant step towards improving plant safety.

Consider what happened during Harvey. Nearly half a million gallons of gasoline spilled out from just two tanks owned by one of the largest pipeline operators. The exact cause of the leak is still under investigation. The pounding rainfall also reportedly sank floating roofs of at least a dozen large storage tanks leading to leaks. At least two dozen storage tanks holding various refinery materials have collapsed spewing out carcinogenic aromatics – Benzene, Toluene and Xylene. API standards mandate that floating roofs should be designed to withstand a rainfall of 250 mm in 24 hours. Harvey brought more than double that rain. Perhaps on hindsight, we need to redesign and strengthen floating roof tanks for a higher rate of rainfall. It will most certainly add to the cost, but would be a small price to pay for protecting the environment. Increased frequency of inspection, maintenance and structural audit of large storage tanks should also help. Clearly storage tanks bore the brunt of the storm surge. The damage would have been less with reduced inventory.

It must be mentioned here that some refineries were able to increase the levels in their storage tanks during the build-up to Harvey. This made the tanks less buoyant and less vulnerable to floating when the water swamped the tank farm.