Offline vs. Online Turbine Cleaning
Offline vs. Online Turbine Cleaning
By Jessie West | March 23 2021
Gas turbine cleaning methods can be conducted online and offline, and the cleaning process differs depending on whether the system is running or not. Each method features its own advantages and disadvantages. Facilities must make decisions for each turbine. Deposit amounts and loss of function will play roles in choosing the best cleaning option.
Why You Need Gas Turbine Cleaning and When to Do It
Turbine cleaning prevents fouling of the system. During operation, approximately 80% of turbine performance drops stem from unit fouling. You can schedule regular cleaning to decrease fouling and reduce performance losses.
Fouling occurs when deposits form on the turbine components. Deposits can appear on the blades or even in the compressor. The buildup of these deposits negatively impacts performance and efficiency. Air flowing through the turbine carries particles that contribute to fouling. Salts in the air, turbine exhaust, industrial pollution, insects, dust, mineral deposits or oil leaks from inside the turbine also cause fouling.
Fouling reduces performance in the turbine. A drop in performance from deposit accumulation requires cleaning to be resolved. Signs that may indicate issues in a turbine include a rise in operating temperatures, faster speeds, more vibrations, lower efficiency, reduced pressure ratio or more power consumption. When fouling causes these problems, cleaning the turbine can fix these issues. Regular cleaning can also prevent these turbine operation problems.
Routine online and offline gas turbine cleaning methods keep the system functioning properly. The frequency and type of cleaning methods used depend on the facility’s needs. A group of petrochemical experts advised in a paper that each site needs to create a customized schedule that includes the following:
- Time between cleaning cycles for online and offline cleaning
- Whether to use online, offline or a combination method
- How long each cleaning cycle should last
- Length of time for each rinse cycle
- Cleaning products to remove fouling
EAI can accommodate the online and offline cleaning schedules, as well as emergency cleaning services. EAI can do everything from inspecting to cleaning. We inspect the turbines to help facilities decide the best options for each parameter above. EAI can also conduct the gas or steam turbine cleaning.
Online vs. Offline Turbine Cleaning Methods
Online and offline turbine cleaning methods work together to provide maximum benefits. Alternating between both is best, but in some situations, you may need only one cleaning method at a time.
Offline cleaning deeply cleans the turbine. This method will restore all lost efficiency and power caused by fouling. However, offline cleaning requires shut down before cleaning is performed. This process requires up to 36 hours. Managers may not choose this method as often as needed in an effort to save money and time. However, recovering performance and power offsets these downsides of offline cleaning. Sometimes, fouling affects turbine performance unexpectedly and a turbine needs unplanned cleaning to restore operation. Scheduling regular offline cleanings can help reduce the likelihood of unscheduled shutdowns.
Online cleaning allows the turbine to continue operation while being cleaned, so facilities do not lose time or revenue from shutting down turbines. This type of cleaning prevents fouling between offline cleanings and protects blades from corrosion. Online cleaning helps keep turbines clean until a scheduled offline cleaning. This cleaning method can extend the time between needed offline cleanings. However, it’s still important to schedule routine offline cleanings to ensure optimal performance.
Overall, it’s important to make both online and offline cleaning components of turbine maintenance and a cleaning schedule. Using both cleaning methods boosts operations and minimizes disruptions.
Gas Turbine Cleaning Best Practices
Gas turbines need regular cleaning to avoid decreased output caused by fouling. Four types of cleaning exist. One of these methods — abrasive cleaning — is no longer popular. The three other cleaning types include online, offline and hand cleaning. The last method is time-consuming.
Hand cleaning takes off heavy deposits of fouling on the inlet guide vanes (IGVs). It is only for use in long-neglected turbines. A compressor may also need hand cleaning during a complete overhaul. For the best results, use a combination of offline and online cleaning. These two methods remove fouling and keep buildup at a minimum.
Deposits can wash off the blades into the compressor. Cleaning and rinsing the turbine removes these contaminants. Rinsing is critical to cleaning. Offline washing only loosens dirt from the turbine, which goes deeper into the system. Rinsing removes it.
Benefits of Turbine Cleaning
A poorly functioning turbine reduces overall plant efficiency and shortens the turbine’s life. Regular cleanings remove fouling and restore functionality and performance. Data shows an increase in work capacity in a 45 MW turbine. The system received hand, offline and online washing regularly over 15 weeks. The combination effectively improved functionality, and the turbine’s work performance increased by 35%.
Online washing alone increases performance, but it must be combined with offline cleanings to maintain the gains in efficiency. Combining online and offline cleaning prevents the loss in production, money and efficiency caused by dirty turbines. Clean turbines operate efficiently and last longer. Invest in cleaning to save time and money in facility operations.
Choose Environmental Alternatives, Inc. for Your Turbine Cleaning Services
Turbine cleaning from us at EAI brings your facility quality services and products. We use the best online and offline methods to remove fouling and restore functionality to turbines. Schedule offline cleanings in advance to choose the best time for a turbine shutdown that minimizes the impact on operations. Online cleanings can happen anytime.
Get started today by contacting us at EAI for a service request or for information on our services and the products we use.