Salt and Corrosion Damages

The main damage caused by sea salt is hot end corrosion of the turbine blades. Hot end corrosion is mainly caused by sodium sulfate (Na2SO4) which is formed when the sodium present in salt-laden inlet air reacts with sulfur from the engine fuel at high temperatures. 

As the turbine firing temperature increases, sodium sulfate liquefies and attacks the coating of the turbine blades, causing irreversible damage and leading to performance losses, early failures and expensive repairs.

Upgrading the inlet systems to (H)EPA prevents the salt from entering the inlet, stopping the process of hot end corrosion caused by sodium sulfate before it begins.

 Salt penetration of gas turbine air inlet systems

On an offshore platform without an inlet filtration system to protect the engine, a typical LM2500+G4 engine would ingest 800kg [1750lbs] of salt in a year... about the weight of two fully grown polar bears!

Traditional F7-rated high velocity filter systems coalesce and remove water well, but still let through about 70kg [155lbs] of salt per year. Moving to a medium velocity filtration system with an F7 prefilter and F9 final filter efficiency lowers the ingestion to about 5kg [11lbs] - still representing an unacceptable salt level to many users due to the risk of  hot corrosion.

Where maintaining peak performance is critical, the industry is now looking at (H)EPA filtration. Moving to a final multi-stage system such as F7 with a final EPA E12 filter lowers the salt ingestion to approximately 15 gr [0.5oz] per year, more than 5000 times less than a typical high velocity system.

Read more about our air inlet protection for marine applications here.

 

Corrosion Test: Not All Filters Are Created Equal

Four static E10 efficiency filters were tested in Camfil’s mobile test lab at a power generation site located on the coast of El Segundo, CA. Copper and silver corrosion coupons were installed to measure how corrosive the air downstream of the filters were. Competitor filters all had between 6900 and 7700 angstroms of corrosion for the copper coupons (image below). Meanwhile, the Camfil CamGT filter had 3300 angstroms of corrosion – less than half the corrosion rate of the other filters! This shows that filter efficiency is not enough to prevent corrosion - filters should be bypass free, have vertical pleats, and good drainage capabilities to reduce corrosion risks. Learn more about these features: http://www.camfil.com/Campaigns/CamGT/features/# 

Location Oxide CU2O Sulfide CU2S Total Å ISA Class

Camfil CamGT 4V-300 E10 Efficiency

323.5 3063.4 3386.7 GX

Competitor A E10 Efficiency

904.6 6845.1 7749.7 GX

Competitor A E10 Efficiency

847.6 6455.6 7303.2 GX

Competitor A E10 Efficiency

515.9 6431.4 6947.3 GX
Ambient Air 621.5 54041.1 54662.6 GX

 

Classification of Reactive Environments

Severity Level

G1 Mild G2 Moderate G3 Harsh G4 Severe

Copper Only

<300 <1000 <2000 >2000


Corrosion Coupons Test

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