How One Power Station Reduced Compressor Wash Waste by 90%

Compressor deterioration is one of the biggest causes of gas turbine performance loss.

You may not even realise it, but avoidable lost power quietly eats into your profits, while unscheduled shutdowns for maintenance interrupt operations with costly consequences.

Approximately 70% of gas turbine performance loss can typically be attributed to

gas turbine compressor deterioration caused by blade fouling. Upgrading your wash system can:

• Reduce downtime
• Lower waste generation
• Improve reliability
• Create more opportunities to recover compressor performance.

The price of the upgrade is recuperated many times over in regained power and reliability.

Today we’re looking at the results a real customer achieved following a gas turbine compressor wash system upgrade with us. Find out how we helped and the improvements they’ve reported…

Gas turbine compressor fouling issues

As a general overview, gas turbine compressor fouling reduces airflow and compressor efficiency, resulting in:

• Reduced power output
• Increased fuel consumption
• Lower compressor discharge pressure
• Higher heat rate
• Reduced overall thermal efficiency

Gas turbine sites should conduct a regular cleaning schedule to minimise these issues and keep their site running safely and efficiently. However, old wash equipment compromises the efficacy of cleans, leading to a number of issues and expenses.

The customer

A large combined cycle power station:

• 2 × GE 9FA gas turbines
• 720 MW combined generation

The problem

The power station put out a tender to upgrade their offline wash system. The existing GE wash system had been operating for over 10 years and was suffering:

• Exhaust duct flooding
• Premature exhaust bellows damage
• Fuel pigtail flooding
• High wash waste volumes
• Labour-intensive operation
• Obsolete components
• Limited cleaning flexibility

They stipulated they wanted to resolve/improve all the above issues while reducing downtime and cutting down the existing equipment as much as possible.

The solution

After a thorough evaluation of the site and requirements, we supplied and retrofitted off-line wash nozzles and a fully automated wash delivery system:

• Retrofit off-line wash nozzles for both GE 9FA gas turbines (could be installed in less than one working day)
• Fully automatic wash delivery system
• Integration with the site’s Distributed Control System (DCS)

While the specialised wash nozzles inject atomised cleaning solution for full, effective blade coverage, the wash delivery system also plays a critical role. This system, with a modern DCS in place, was designed to improve efficiency while reducing operational issues.

Accurate dilution of cleaning chemicals, automatic heating of solution to optimum levels, and auto-pumping it to the cleaning nozzles streamlined the process and eliminated human inaccuracy during cleans.

Results

The customer was extremely pleased with the results achieved:

Direct financial savings

There have been significant financial savings made thanks to the new wash system:

• Approximately £22,500 saved per off-line wash in lost production (due to shorter downtime)
• Estimated £45,000 per exhaust bellows replacement avoided
• Reduced labour requirements
• Reduced maintenance requirements

Operational Benefits

• Elimination of fuel pigtail blanking requirements
• Elimination of engine flooding issues
• Improved automation through DCS integration (Distributed Control System)
• Increased reliability through PLC-based controls (Programmable Logic Controller)
• Reduced operator intervention
• Greater flexibility to perform off-line washes during planned and unplanned outages
• Opportunistic cleaning: due to the significantly shorter wash time, the operator is encouraged to perform off-line washing during both scheduled and unscheduled outages.

Performance Recovery

Typical performance losses of 3-4% can occur after approximately 8 weeks of operation: equivalent to approximately 8 MW on a GE 9FA that can potentially be recovered through effective compressor cleaning.

Get in touch

This project demonstrates that upgrading a compressor wash system can deliver benefits far beyond maintenance requirements. Reduced downtime, lower waste volumes, improved reliability and greater operational flexibility all contribute to a more effective compressor cleaning programme with huge benefits for the operation as a whole.

If your compressor wash system is becoming increasingly labour-intensive, difficult to maintain or costly to operate, contact Rochem FYREWASH® to discuss upgrade and retrofit options. We’ll be happy to talk through your specific requirements.