refractory application for extreme firing condition in … application for extreme firing condition...

Refractory application for extreme firing condition

in the regenerator of glass melting furnaces

Sandra Fischer, Rongxing Bei, RHI Glas GmbH, Germany

For part of “thermal chemical regenerator”: Joaquín de Diego, Praxair, Inc., USA

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, October 22-25th 2017

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Content

• Pet-coke firing

• Sodium silicate glass

• Thermal chemical regenerator

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Content

• Pet-coke firing

• Sodium silicate glass

• Thermal chemical regenerator

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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Sample 1 Sample 2 Sample 3 Sample 4 Sample 5

Cr2O3 11.9 9.0 1.1

Fe2O3 24.9 14.3 20.9 11.0 9.8

NiO 7.6 6.7 6.7 4.4

V2O5 30.1 7.3 29.3

From the pet-coke ash:

High amount of Cr, Fe, Ni, and V

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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V2O5 total in flue gas (Kg / ton glass)

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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Problem for glass production The unburned pet coke powder can go into the regenerator,

A re-firing within regenerator can happen:

High temperature and strong thermoshock

Destruction of the regenerator crown, wall and checker

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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Magnesia Zircon (RUBINAL VZ) :

Forsterite formation during brick production

ZrSiO4 + 2MgO Mg2SiO4+ ZrO2

Protection of the Periclase (1) by matrix out of Forsterite and ZrO2

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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Example Magnesia zircon brick (Rubinal

VZ) shows corrosion of half

layer after 6 years

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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Corrosion Test

Hot face not corroded

excellent resistance against carryover and V2O5

Chrome corundum with 10% Cr2O3 (DURITAL RK10)

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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Corundum (1) is protected by chrome corundum solid solution (2)

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Pet-coke firing

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Checker Lining Recommendation

Top Layer: Magnesia Zircon and Chrome Corundum

Hot zone (>1100 °C): Magnesia Zircon

DURITAL RK10

RUBINAL VZ

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Content

• Pet-coke firing

• Sodium silicate glass

• Thermal chemical regenerator

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Sodium silicate glass

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Component ratio

SiO2 : Na2O

Name

3,9 to 4,1 High silicic acid water glass

3,3 to 3,5 Neutral soda glass

2,0 to 2,2 Basic water glass

Sodium silicate (water glass):

Amorphous melts of alkali silicates

Waste Gas containing:

NaOH (gas firing)

Na2SO4 (oil firing)

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Sodium silicate glass

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For gas firing:

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Sodium silicate glass

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Gas firing:

Condensation zone,

MgO (ANKER DG1)

After 5 years

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Sodium silicate glass

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NaOH had no effect on MgO – it entered

the Magnesia-crystal to form a „ring“ on

the surface

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Sodium silicate glass

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Oil firing:

Condensation zone,

magnesia-Zircon

After 12 years

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Sodium silicate glass

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1: cavity

A and B:

matrix of forsterite and

ZrO2

C: ZrO2

Even after 12 years of

application the matrix

has done a good job!

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Sodium silicate glass

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Content

• Pet-coke firing

• Sodium silicate glass

• Thermal chemical regenerator

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Process of thermochemical regenerator

CH4, H2O, CO2, CO and H2 exist in

different height of checker work

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Test setup

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Test setup

Different refractory samples

• installed in doors

• installed in ports

• for 8 months

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Refractories in the temperature-range of 1150-1200°C

All wall samples containing

mullite:

zirconia mullite

fused mullite

sintered mullite

are damaged!

Reason:

Na2O (out of waste gas) +

Mullite

Nepheline formation

zirconia mullite

Baddeleyite, syn ZrO2 +++

Corundum, syn Al2O3 +++

Mullite, syn Al6Si2O13 +

Nepheline NaAlSiO4 +

SO3 0,30

Na2O 4,16

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Refractories in the temperature-range of 1150-1200°C

Checker sample

in TCR

Magnesia and

magnesia zircon:

• no interaction with Na2O

• no damage

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Magnesia 97

Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Refractories in the temperature-range of 1150-1200°C

What is important for magnesia with C2S-bonding?

MgO-MgO-direct bonding!

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Case Example

Magnesia 97

direct bonding

Magnesia 97 direct bonding used as checker in one float furnace:

• 14 years

• Firing with heavy oil and gas

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Case Example

Magnesia 97

direct bonding

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Case Example

2CaO.SiO2 disappeared (corroded by Na2O and V2O5)

MgO-MgO direct bonding

remains (circles)

Magnesia 97

direct bonding

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Conclusion

Pet-coke firing (Vanadium attack):

• Magnesia zircon (RUBINAL VZ) has good performance.

• Chrome corundum (DURITAL RK10) even better

Sodium silicate glass (Strong NaOH attack):

• Magnesia zircon (RUBINAL EZ) for oil firing

• Magnesia (ANKER DG1) for gas firing

Thermal chemical regenerator:

(Changing between reducing and oxidising atmosphere):

• Basic materials showed no attack

• MgO-MgO direct bonding is important

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Refractory for extreme firing condition in regenerator

2017 ICG Annual Meeting & 32nd Şişecam Glass Symposium, Istanbul, Oct 22-25th 2017

Thank you for your attention

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