Background
Mines in the Bowen Basin experience high levels of corrosion due to build-up of corrosive ions such as chlorides and sulphates. This results in high conductivity and highly corrosive water used in the coal washing process in the Coal Handling and Preparation Plant (CHPP).
Initial assessments recorded baseline corrosion rates ranging from 30 to 50 MPY, reflecting a high degree of severity.
These elevated corrosion rates posed significant risks to the client, including increased unplanned maintenance and replacement costs, potential equipment failures leading to operational downtime, and possible safety hazards for personnel.
To help mitigate these risks Water Treatment Services (WTS) initiated a trial using a tailored corrosion inhibitor solution.
WTS solution
WTS supplied a corrosion monitoring and dosing system to facilitate a plant trial. The system included dual corrosion monitors to ensure reliable data collection. Initial dosing was set to achieve 100ppm for passivation, followed by a maintenance dose of approximately 30ppm based on make-up water.
The trial demonstrated a rapid reduction in corrosion rates from severe to much lower levels (<10 MPY) upon introduction of the corrosion inhibitor.
WTS key solutions
- Deployment of WTS 5-0017 corrosion inhibitor
- Continuous monitoring and adjustment of dosing rates
- Calibration and maintenance of analysers and probes
- Strategic planning for chemical supply to ensure uninterrupted dosing
- Ongoing optimisation based on seasonal changes and system performance.
Results and Benefits
- Significant corrosion reduction: Corrosion rates dropped from severe baseline levels (30–50 MPY) to below 10MPY values.
- Improved system reliability: Consistent dosing and monitoring minimised potential for unplanned maintenance and system downtime.
- Operational efficiency: Automated monitoring and optimised dosing reduced manual intervention.
- Cost savings: Lower corrosion-related failures and maintenance will help to reduce overall operating costs.
