Case Studies - Equipment

IGS ClearStream Chromium-6 Filtration for Safe HVTS Application

Introduction: Gas Turbine Corrosion IGS was invited to apply HVTS cladding to mitigate high-temperature corrosion on a high efficiency, air-cooled gas turbine installed at a power & light facility in the United States.

High-Temperature Gas Turbine Corrosion

The turbine’s base metal spalling challenges were leading to premature failure of the blades and other downstream parts. This was increasing outage frequency and cost. Affected areas included the upper half CDC, upper half OTS, six upper and lower half diffusers, upper and lower inner barrel, lower half CDC combustion cans and five armway covers.

Surface Preparation

The surface condition of the turbine components as received was consistent with the problem description provided by the asset owner. The surface exhibited corrosion and evidence of spallation due to high temperature exposure. No additional grinding was required as the initial blast application by IGS was sufficient surface preparation for HVTS application.

Ventilation and Filtration In compliance with the IGS Hexavalent Chromium Exposure Control Plan, the company utilized radial fans with ClearStream filtration systems. The system features a HEPA filter in the upper and lower half enclosures providing adequate ventilation. Flexible ducting...

HVTS Application

The High Velocity Thermal Spray (HVTS) process included true high velocity application using IGS’s proprietary Metalspray 3000 Low Stress application equipment. This cutting-edge technology allowed IGS to apply cladding with much greater density and decreased permeability, while keeping internal cladding stresses low.

In this process, IGS achieved the smallest possible thermal spray particle sizes and applied them in as dense a pattern as possible. This type of application increases the distance of pathways leading from the surface of the thermal spray to the substrate beneath. Permeation levels are eliminated and erosion resistance is increased.

Future Projects IGS engineers confirmed the viability of a full lower-half coating plan (focusing on the CDC and OTS).

Gas Turbine Corrosion Mitigated by HVTS and Hex Chrome Filtration System

Introduction IGS was invited to apply HVTS cladding to mitigate gas turbine corrosion caused by high-temperatures. The high efficiency, air-cooled gas turbine is installed at an electricity, water and gas authority facility in the Middle East.

High-Temperature Gas Turbine Corrosion

High temperature gas turbine corrosion on unprotected casing surfaces causes wear and plugging. Protecting turbine components with high nobility cladding protects them from HT corrosion. This turbine’s upper and lower half OTS and CDC suffered base metal spalling challenges with a total affected area of more than 26m2 .

Turbine Surface Preparation and Blasting

The initial condition of the turbine components was acceptable. Pitting was discovered on the upper half OTS after clean blasting. Minor pencil grinding was required for the upper half OTS substrate to comply with IGS’ surface acceptance criteria. No additional grinding was required on the upper half CDC and lower half OTS and CDC as the initial blasting application by IGS was sufficient surface preparation for HVTS application.

Ventilation and Chromium-6 Filtration

In compliance with the IGS Hexavalent Chromium Exposure Control Plan, the company utilized radial fans with ClearStream filtration systems containing a HEPA filter in the upper half and lower half enclosures that provided adequate ventilation. IGS installed and used special hexavalent contamination booths and protocols throughout the project execution to reduce the risk of external contamination within the work area.

IGS vacuumed and removed all hazardous material into drums for disposals. Used filters were placed in 6 hazmat filter bag modules and stored in the same location as the barrels containing the hazardous waste. Hexavalent Chromium measurements were taken at the ducting outlet of the upper half and lower half enclosure.

HVTS Application

The High Velocity Thermal Spray (HVTS) process included true high velocity application using IGS’s proprietary Metalspray 3000 Low Stress equipment. This cutting-edge technology allowed IGS to apply cladding with much greater density and decreased permeability, while keeping internal cladding stresses low.

IGS achieved the smallest possible thermal spray particle sizes and applied them in as dense a pattern as possible. This type of application increases the distance of pathways leading from the surface of the thermal spray to the substrate beneath. Permeation levels were virtually eliminated and erosion resistance increased.

Project Conclusion The project was executed successfully without any major issues or concerns. The gas turbine is now protected from oxidation, significantly reducing any future recurring maintenance costs.
IGS HVTS applied to a CFB Boiler pressure parts to prevent boiler tube erosion

Proactive CFB Boiler Maintenance Saves $ Millions and Triples Run Cycles

CFB Boiler Protected with IGS SMARTGard® This coal-burning boiler was commissioned in 1998 with an 11,450 sqft (1064 sq.m.) heating surface and 1.2 million pounds per hour (544 t/h) steaming cap. IGS first applied HVTS in 2020 and monitored the...
PROBLEM: The annual cost from forced outages, RIK, general maintenance and electrical cost associated with each unit could reach an average of 8-12 Million dollars. SOLUTION: IGS SMARTGard addressed the problems and increased the run cycles from 4-6 months to...
1. Before IGS SMARTGard See the bare tube condition prior to the IGS SMARTGard HVTS application. Notice hard edges around discontinuity from erosion damage where ash build-up has deviated material flow into the unprotected substrate.  
2. IGS HVTS Applied In order to prevent further substrate wastage IGS has cladded the area with HVTS as opposed to having to cut and replace tubes. Pictured is the area of low tube thickness now protected by IGS cladding....
3. Ceramic Top Coat Once the cladding process has been completed, IGS applies a proprietary ceramic top coat as a wear indicator during future outage inspections to help navigate future coating plans.  
4. After a 14-Month Run Cycle The coated area after a 14-month run cycle appears on the right. The presence of ceramic top coat (Green) can still be identified meaning underlying thermal spray cladding is still at 100% as-applied condition....
The Benefits of SMARTGard HVTS cladding reduces tube wear and increases overall production. This reduces costs associated with maintenance from both planned maintenance and forced outages. Reducing the need for welding and eliminating the requirement for refractory in some areas...

SMARTGard®: Weld Overlay Alternative for Boiler Pressure Parts

A waste-to-energy plant in Turin, Italy, was preparing for an outage on one of their lines. They were waiting for approval from the notified body to carry out the weld overlay. The outage was nearing, and the approval was yet...
Power Plant
Corrosion of the Boiler Pressure Parts The plant, built by CNIM, was commissioned in 2014. Following several years in operation, they noticed corrosion in the second pass of the boiler. Alloy 625 weld overlay has already been installed in the...
Selecting a Suitable Solution IGS SMARTGard HVTS was selected for several reasons. Strong global references in similar applications supported by laboratory testing. HVTS is not a welding process – the pressure part temperature stays below 150C during the application, therefore,...

Plant Replaces Weld Overlay in its CFB Boiler

This CFB boiler built in the mid-1990s is designed to burn anthracite coal, hazardous waste coal piles located throughout Pennsylvania. The plant observed severe erosion and metal wastage on the boiler tube due to how these combustors operate. Over the...
thermal_spray_coatings

SMARTGard® Thermal Spray Stops Alloy T24 Fireside Corrosion in Supercritical Boiler

This Power Plant provides steam to nearby industrial facilities using sustainable biomass (such as SBP, GGL, FSC, and PEFC) and industrial by-products (such as bio-propane) to generate power and heat.
SUPERCRITICAL BOILER The boiler has five rows of six burners on two sides. These burners are fed with coal, bio-propane, wood, and MBM (Meat and Bone Meal) – animal residue foam injected into the boiler. MBM is very erosive, so...
A SUPER ALLOY T24 BOILER The unique feature of this boiler is that it is one of the first boilers manufactured with alloy T24. T24 material is a novel superalloy, designed for strength at high temperatures that does not require...
ALLOY T24 WELDING ISSUES Welding this superalloy is difficult, especially without annealing or post-weld heat treatment. Non-alloy steel, a material used to produce typical boiler tubes, PH 265GH, is the easiest material to weld. The superheater material, 10CrMo9-10, is known...
As a result, these first boilers manufactured with T24 suffered many leaks after just a few hundred hours of operation. Welding experts from VGA and other parties involved helped them find the solution, enabling them to erect such supercritical boilers...
TESTING HVTS SUPERALLOY PROTECTION As the plant continued having multiple stoppages due to tube leaks, in 2019, they decided to apply a protective cladding onto a test area to evaluate its performance. IGS SMARTGard HVTS was chosen for this on-site...
SMARTGard®: IGS HVTS – High-Velocity Thermal Spray HVTS cladding was also applied onto superheater hanging tubes facing soot blowers. Test areas were installed onto various locations of tube bundles as an alternative to thick metal protection shields.
A LEAK OCCURRED DURING HVTS TESTING After installing the trial HVTS application in August 2019, another forced unexpected shutdown due to a tube leak occurred in December that year. Although initially it was suspected to be in the IGS clad...
QUALITY INSPECTION PROGRAMME UT Quality inspected HVTS cladding and unprotected tubes. They performed tube scanning using a PEC Scan, Pulsed Eddy Current scanning, that delivers specific tube thickness mapping. This inspection was conducted in 2019 and again in 2021. By...
INSPECTION DISCREPANCIES AND RESULTS When comparing inspection results between 2019 and 2021, the inspection company immediately noticed that some areas appeared to have gained thickness. Cyril Narjoz, IGS Boiler Reliability Expert, commented:
“You need to keep in mind that first of all, you never read the same point two years later, it’s impossible. Even when you do the reading on the same spot, during the same inspection or the day later, you...
The inspection results were matched with the positioning of the HVTS cladded area. It was a challenge because it didn’t match the red area or the colored area of the thinning. Moreover, to make it a little more complicated, in...
“Nevertheless, what we can see in the area where we applied the HVTS the cladding, there’s much less thinning. And above the area, we have this red zone where we can notice up to nearly one millimeter per year loss...
FUTURE-PROOFING THE BOILER Initially, prior to evaluating the readings, the plant had commissioned IGS to expand their HVTS cladding scope to protect a 35 m² surface area finishing the band and protecting a band below. However, after evaluating the readings...
HVTS APPLICATION IN 2021 The expanded scope was completed in record time by IGS utilizing additional operational resources to speed up the process, with work proceeding simultaneously on several levels. Plant representative said: “We really appreciated IGS’ flexibility during the...
SUPERHEATER TUBES This project’s second exciting part included the hanging superheater tube bundle with steam at 320 bar / 5400C. These tubes face the soot blowers that are operated at regular intervals to clean deposits of the tube surfaces. Welded...
Cyril Narjoz commented: “Cladding supplied by a different vendor was also applied and tested in a similar area and performed well.  The key difference is – these other tests were sprayed in the workshop before being installed in the boiler....
CONCLUSION As T24 material is extremely challenging to weld. One of the major benefits of the IGS HVTS solution is that no welding is involved in its application. Since HVTS is not welded, it does not generate any alteration to...

Twice as Good and Twice as Fast. SMARTGard®: Reliable Boiler Tube Protection

Most Modern Power Plant The plant was completed and commissioned in 2010. The power plant’s production capacity is 180,000,000 kWh per year. The heat and energy produced is mainly used by a paper mill and the local municipality’s district heating...
PROBLEM After discovering metal wastage in 2014 and having to replace a panel section in 2016, engineers decided to protect new panels with thermal spray cladding. SOLUTION Integrated Global Services (IGS) proposed SMARTGard, a high velocity thermal spray (HVTS) alloy...
Boiler Metal Wastage In summer 2014 corrosion was identified on the unprotected boiler tubes, above the weld overlay section. New panels were installed to replace corroded sections, needing cost-effective protection, which would also be faster to apply than weld overlay....
2020 Inspection Spot check inspection of the boiler in 2020 on both HVTS alloy cladding applications showed no reduction of metal thickness. The Power Plant’s boiler engineer, commented: “We are pleased with the service provided by IGS. Reliability and efficiency...
Routine Boiler Inspections IGS have certified inspectors who are able to evaluate the performance of any boiler tube protection, highlighting areas of improvement and advising on a suitable solution for erosion and corrosion issues.

HVTS Cladding- Solution to tackle Fireside Corrosion and ensure Long-Term reliability

EPRI Study In the mid 2000s, a US power utility owner and EPRI performed a long-term study to determine if thermal spray technology would protect the sidewall tubes (adjacent to burner levels) from thinning caused by reduced sulfidizing atmospheres. A...
PROBLEM The boiler was experiencing tube wall thickness wastage caused by operating the boiler in a reducing atmosphere (low NOₓ burners)which results in sulfidation corrosion. This boiler is the newest of the 1300 mw units but experienced very similar corrosion...
SOLUTION During the Fall of 2019, the plant was in a major planned outage. A full furnace scaffold was installed for boiler maintenance and a tube assessment was performed. During the inspection, new wastage was discovered on the upper front...