CALCINER BLOCKAGE INCIDENT INVESTIGATION

November, 11. 2007

Project conducted by Aleksandar Adzic – Lafarge Plasterboard – Matraville Plant

Consequences of the incident

  1. The first shutdown was caused by S149 Bucket Elevator break down resulting in 8 hours and 48 minutes of production time lost.
  2. The second shutdown was for blocked Calciner. It occurred on Calciner restart after the first shutdown. This resulted in 27 hours and 54 minutes of production time lost.

In this incident we have identified 3 major causes

Lack of preventative Maintenance of all equipment associated with Plaster Mill

  • Calciner is the bottleneck of our plant and therefore needs to be operated 100% of the time (including on regular maintenance days) leaving not time for preventative maintenance
  • Matraville plant has one of the highest AMU and ME for Calcining in gypsum division

Operator training

Due to the fact that Calciner is running most of the time, our operators do not have regular exposure to shutdown and start-up. This affects their troubleshooting abilities

Control System (Conductor NT)

Our plant was established in 1992. Since the we have updated our control system only once (in 1999) and we are experiencing many problems since start of this year. The system is experiencing problems with communications and sometimes present inaccurate feedback to operators and electricians.

Proposed Resolutions

These are measures we have taken or are in the process of implementing in order to eliminate re-occurrence of this type of incident

  • Detailed annual plan for preventative maintenance in plaster-mill will be established. Sales department and Production planning will have to get involved in maintenance planning to avoid stock shortages as much as possible. Production manager and Maintenance manager will coordinate with other stakeholders in order to provide a minimum of two shutdowns (one of them to be approximately six months after Christmas shutdown). Every opportunity to be used by shift electricians and fitters to check the equipment and machinery in a safe manner. Maintenance manager will create inspection guide and check list.
  • Operator Training: Complete and detailed start-up and shut-down procedure is being drafted by Maintenance manager, Aleksandar Adzic and our most experienced plaster-mill operators. These procedures are to be reviewed and made official by the end of this year. Maintenance manager will be tasked with hands on training of shift electricians and plaster-mill operators whenever there is opportunity. Additional classroom training to be considered. Find out if it is possible to source or create some sort of simulator for training purposes. This will also involve re-assessment of operator’s skills for operating plaster mill.
  • Control System (Conductor NT) – We have the way stirrer alarm activates reconfigured, as well as the way the system determines a shutdown. Once the documented procedures (shut down and start up) are implemented we will ensure the control system reacts as it should – thus basically marry the procedure with the control system (success of this will depend on system’s abilities). A better Plant Change Request form has been developed. This form should help by ensuring any change of the way plant is operating is validated by the PMT, communicated and personnel is correctly trained.

Long term solution for Control System

Our Process Control System (Conductor NT) has reached it use by date and needs replacement. There are three options for ultimately solving our issues with the system:

  • Option 1 – Replace Conductor NT – estimated cost – AUD $250,000.00
  • Option 2 – Replace Conductor NT and Fisher & Porter instruments – estimated cost – AUD $700,000.00
  • Option 3 – Replace Conductor NT, Fisher & Porter instruments and PLC system – estimated cost – AUD $1,200,000.00

SUMMARY

We are addressing maintenance issues and planning

We are addressing procedural and training concerns

We have addressed some specific items in the control system to minimise the likelihood of this event repeating itself.

All calciner start-up will be supervised by a member of PMT (preferable Maintenance manager) till we are confident that our electricians and operators are capable of performing required tasks.

Process Control
PLC control panel

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