Toluene Diisocyanate Remediation from pMDI Contaminated Tank and Process Lines

TDI PROCESS CONTAMINATION PROBLEM

A railcar of toluene diisocyanate (TDI) was mistakenly shipped as pmethylene diphenyl diisocyanate (MONDUR 489, pMDI) to a chemical manufacturing company and unloaded into their receiving tank. TDI froze in the unloading lines and transfer pump.  Note (TDI freezes at 50oF and pMDI at 32oF).  Ambient temperatures during the transfer ranged from 23 to 30oF.

TOLUENE DIISOCYNATE REMEDIATION SOLUTION

Remtech was engaged to remove the frozen TDI from the railcar’s standpipe and receiving facility’s lines, pump, and storage tank and restore normal operating conditions to the plant as soon as possible.

Drum heaters, heat tape, and steam were applied to external lines to thaw the frozen product.  After 48 hours of heating, TDI was drained from the transfer lines.  

Product was pumped and pneumatically transferred from the storage tank and lines to two tankers with off-gas vapors treated by two (2) Remtech off-gas carbon filtration systems connected in series.  65,000 lbs of TDI were removed from the system and transferred into two stainless steel tankers.

TOLUENE DIISOCYNATE REMEDIATION COST/BENEFITS

The frozen TDI was removed from fill lines, pump and tankage without system dissembling or rodding within 48 hours.  Thawing and purging frozen TDI in place significantly reduced costs and time that this facilities unloading facility was out of service.