Thermal Spray Coating for Boiler

Copyright © 2012JGC Corporation All rights reserved

THERMAL SPRAY COATINGAPPLICATIONS

FOR REFINERY & BOILER

JGC CorporationStart Up & Operation Service Department

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Thermal Spray is a technology to form coating by depositing molten materials on metal surfaces at high speed.

MetalAlloyCermetCeramic

（Coating Materials）

Combustion Flame Plasma

Spray Gun

Coating DepositionParticle Impact

Molten Particle Acceleration

Base Metal

（Heat Sources）

Un-molted Meta

Gas Hole

Base Metal

Molten Particle

What is Thermal Spray?


Examples of Field Applications

CDU Tower Corrosion Protection

FCC Cat Section Applications

Boiler Tube Applications

Other Applications

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1. CDU Tower Corrosion Protection


Stainless steel cladding is typically installed in top head of the distillation tower to protect against acid corrosion.

Due to the long service life, corrosion of the metal cladding has been increasing.

Ni/Cr alloy or Ni-base alloy coating is one of the options for top head repair.

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Φ 8500

Clad PortionTop and Weld SeamArea : 65 ㎡42

0025

80

CS Shell PortionTL ～#1 Accumulator TrayArea : 70 ㎡

Example of Actual ApplicationCoating MaterialNi-base alloy + SiO2 Sealing

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Step 1 - Check the site condition and working environment

Step 12 - Remove the materials, equipment, cleaning

Step 4 - Check the appearance of the surfaces to be coated

Step 2 - Carry in the equipment and materials

Step 3 - Setting up, wiring and trial run of TSC equipment

Step 5 - Cure the un-coated area and confined space ventilation

Step 6 - Blasting for removing the scale

Step 7 - Intermediate inspection (visual observation of chips, cracks, etc.)

Step 8 - Grid blasting for surface treatment

Step 9 - Intermediate inspection (visual observation, roughness checking)

Step 10 - Thermal spraying (manual) and sealing

Step 11 - Final inspection (thickness checking, visual observation, etc)

Process of On-site TSC Work

7Work Duration：12 Days


This process consisting of TSC sprayed with Arc Wire Process and “Sealer”

Coating materials are as followsFor TSC = NiCr base alloy or Ni base alloyFor Sealer = SiO2 System material

This coating is applicable from ambient temp to high temperature up to 450℃

Expected lifetime of the coating would be at least 5 years or more （depends on the operating condition)

Hybrid Thermal Spray Coating

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【Sealer】Corrosion resistance material which need the interspaces to fix itself

【EP-JB coating】Corrosion resistance layerwithout interspaces

Hybrid

Composition of Hybrid Coating

【TSC layer】Corrosion resistance layer with interspaces

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Cross-Section of Hybrid LayerDepth of the sealers’ penetration (Ni-Cr system TSC layer)

Above photos show that SiO2 sealer penetrate deeply enough to the poresin the TSC layer ( almost all of the pores are filled with the sealer).

Pores Si penetrate into the pores

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TSCArea

TSC Area

Non TSCArea

After 4 years, performance of TSC was confirmed

TSC area : Sprayed film was still in

good condition and no increase of corrosion was observed

Non TSC area : Surface was rusty and

increase of corrosion was observed

Actual Performance of TSC

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Advantage of TSC Wide range of material selection

High deposition rate of coating

Low cost and simple work

No heat to affect base metal

The best material can be selected for the service.

One third of the cost compared to strip lining.

TSC can be applied repeatedly because there are no metallurgical effect on shell material.

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135㎡ can be sprayed within 2 weeks during TA.


2. FCC Cat Section Applications


2. FCC Cat Section Applications The severest operating conditions.

Erosion caused by catalyst flowHigh temperature corrosion

Damage to mechanical components in FCC Cat Section is a problem for reliable, long-term continuous operation.

Damage can be effectively prevented or mitigated with various metal coatings using TSC technology.

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Feed InjectorAir Distributer

Rx Stripper

Rx Cyclone Internal

Rx PlenumChamber

Slide Valve Stem

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Rg PlenumChamber

Rg Cyclone Internal

FCC Cat Section Applications


Rx / Rg Plenum Chamber HVOF/Cr3C2-Cermet

Anti-Erosion Coating Arc Flame/Fe-Cr-B

Anti- Erosion Coating

Rx / Rg Cyclone Y Sleeve Self-Fluxing Alloy/Fe-Cr-B

Anti-Erosion Coating

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Examples of Actual Applications


Rg Air Grid Nozzle HVOF/Cr3C2-Cermet

Anti-Erosion Coating VPS/Cr3C2-Cermet


Plug Valve Stem HVOF/Cr3C2-Cermet



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Main FractionatorBottom Pump HVOF/Cr3C2-Cermet


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3.Boiler Tube Applications


Confidential

Water leak damage of reheat combustion chamber tube

Corrosive compound contained in fossil fuel ashes and its MPPetroleum Fuel（Heavy oil, Asphalt,Petroleum coke)

Coal

Chemical compound MP ℃ Chemical compound MP ℃

V2O5 690 K3Fe(SO4)3 618

NaVO3 560 K3Al(SO4)3 654

Na2SO4 884 Na3Fe(SO4)3 624

2Na2O･3V2O5 565 Na3Al(SO4)3 646

10Na2O･V2O5 573 KFe(SO4)2 694

Na2O･V2O4･5V2O5 625 NaFe(SO4)2 690

5Na2O･V2O4･11V2O5 535 Na2SO4/K2SO4 884/1,069

Damage of Steam Generating Boiler Tube

Cross section of reheat combustion chamber tube damaged by high-temperature corrosion

Cross section of air heater tube damaged by high-temperature corrosion

Cross section macro structure of reheat combustion chamber tube of coal fired boiler

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Example 1 : Thermal Spray for Generating Tube

Industry ： Iron and Steel Capacity : 260t/h (Evaporation)Spray area ： Generating Tube inside furnaceMaterial ： 50Ni-50Cr

Applying Thermal Spray Finished Repair damage by

weld overlay

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Example 2 : Thermal Spray for Generating Tube

Industry ： Paper makerCapability : 120t/hSprayed area ： Generating Tube inside furnaceMaterial ： 50Ni-50Cr

Spraying Finished

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Corrosion resistance of thermal spray layer applied to superheater tube of Heavy oil fired boiler

Test result of Corrosion resistance/50Cr-50Ni

Corrosion test result of Ni-Cr-(Fe) alloy with 80%V2O5-20%Na2SO4 ashes

Mass Loss(mg/cm3 16hr)

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４.Other Applications


Other Applications１． Rotating Machinery Applications Developed and used for wear protection and thermal

barrier of machine parts. Permanent repair of critical components of rotating

machines. pump shafts, mechanical seal sleeves, etc. piston rods, piston rings gas turbine blades, combustion chambers

２． Aluminum Thermal Spray Coating for CUI protection Al coating is the ultimate option for CUI protection. Plant owners no longer need to be concerned about

CUI.

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Thank youfor

your attention!

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Documents

Thermal Spray Coating for Boiler