Disaster Management Strategies
A Look at Disaster Management Strategies for Chemical Process Industries
Actions Initiated by Plant Personnel
The detailed activities with respect to the flood and the potential chemical disaster management that were carried out by the plant are mentioned below:
Activities done during pre-disaster (i.e. before the ingress of flood water into plant
In view of the information it had received about the release of water from the Ukai dam, the plant had carried out certain mitigation and preparedness activities to reduce the human and property losses. It was ensured that adequate manpower was available to essay the safe shutdown of the plant. The personnel are located at safe elevations in the control room after carrying out the required shutdown activities.
- The hazardous chemicals, which could react violently when in contact with water, were shifted to higher elevations.
- The trip logic shutdown system for process control and safe start-up and shutdown were initiated to ensure safe shutdowns of the plant in the ‘Auto’ mode.
- Two emergency lights were kept charged and ready for use.
- Arrangements were made for food packets, drinking water etc. for the shift personnel.
- Adequate isolation-valve handles were provided to the field operators for closing certain isolation valves in the case of an emergency.
- Breathing air apparatus and fire extinguishers were kept in the control room and the fire station at higher elevations.
- The communication system was checked and deficiencies rectified.
- The rotating equipment tripped due to electrical supply failure and diesel generator sets started on auto ‘mode’ for providing electrical power to safety-related critical equipment were verified.
- The isolation of high-pressure loops (HP) from low-pressure loops (LP) was done through the programme matrix logic, monitored through the distributed control system (DCS) with the available, uninterrupted power supply (UPS). The loops were also kept pressurised by synthesis gas, as per the standard operating procedure (SOP).
- Shutdown of crackers (for cracking ammonia gas into synthesis gas) was done as per SOP and cooling was completed.
- Battery-limit isolation valves of natural gas line, steam, etc. were isolated manually.
- The UPS supply to field control panels, electrical supply to MCC panels and the diesel generator power supply was cut off, and the diesel-driven firewater pump was stopped.
During a disaster (i.e. after the flood water entered the plant premises):
There were certain lapses with respect to the emergency response activities, such as:
- There was total failure of the communications system, both within and outside the plant premises.
- Due to the rise in the water level, there was no mobility of plant personnel and other rescue teams
- The food supply to the personnel stationed on first floor of control room was hindered due to flood-water level and the emergence of large numbers of venomous reptiles.
- There was no drinking water supply.
- Muddy water had entered the ground floor of the control room.
Post flood scenario:
The floodwater started receding after three days. The senior plant personnel could finally enter the plant premises and the shift personnel who were inside the plant for three days could be relieved from their duties. There were no casualties due to the flood disaster; however, there was loss of property due to damage of equipment such as pump motors, diesel generator sets and the Distributed Control System (DCS) bus isolation card. The motors were decoupled, cleaned thoroughly, applied with a thick varnish coat and the bearings replaced. The DCS electronic cards were cleaned, dried thoroughly and reinstalled. Certain activities were done as top priorities to restore the supply of drinking water, electricity and establish communication systems for the plant and residential colony. The instrument loop and trip logic simulation test was done to check for instrumentation communication and functioning as per design intent.