ISOMEMBRANE® introduction

Our special HASLE ISOMEMBRANE® technology presents a unique solution to the problem of

boiler dead space sealing at both coal- and gas fired power plants.

What is the problem?

Across the world, the design and operation of power plants face the challenge of sealing the

roof on Pulverized Fuel (PF) fired boilers, against ingress of fly ash into the so called dead

space on top of the boiler.

In all steps of the operation of the boiler, the pipe work in the boiler - carrying water and

steam under high pressure - will move slightly due the thermal expansion of the metal. This

movement causes the concrete wall of the boiler to crack, in the areas around the pipe lead-in.

Locating a durable metallic sealing to prevent fly ash from entering the leaks created has

been difficult.

As the pressure outside the boiler is lower than that of the boiler house environment, flue gas,

carrying the fly ash from the incineration of the pulverised coal, will pass through the leaks in

the boiler wall. Once outside the incineration chamber, the fly ash will precipitate in the dead

space or be carried further towards the top of the boiler (convection pass, penthouse etc.)

Emission of fly ash is not the sole problem of leaks in the boiler. Leaks around the front

cross, nose arch, ash hopper and the expansion joints, result in ingress of cold air from the

atmosphere. This greatly reduces the efficiency of the incineration process.

Why use the ISOMEMBRANE®?

The following consequences of the leakage have been experienced:

The build up of fly ash may grow to several meters in height, with a combined stress

of several hundred tons on the boiler roof. Over time, this strain on the building structure may

result in metallurgical fatigue, and in rare cases, entire boilers have collapsed under the

weight of the fly ash. Ingress of steam or water in the fly ash layer will further increase the

risk of damage, as the weight will increase accordingly.

The hot fly ash constitutes good insulation conditions, and un-cooled construction

parts such as rods and hangers may reduce in strength and lifetime, due to overheating.

Until the thick layer of fly ash has cooled down and removed, a process that normally

takes one week, repairs to pipe works is impossible. With the ISOMEMBRANE® in place, the

cool down process is shorter, and repairs possible immediately, as there is no ash layer to

remove first.

The bypass of flue gas and fly ash into the upper dead spaces of the boiler

environment will reduce the combustion efficiency. Tight pipe lead-in’s with an

ISOMEMBRANE® seal will ensure the best incineration environment, as flue gases and fly ash

is kept in the incineration chamber and routed through filters to the chimney.

Loss of energy because of heating up ingress air and extra load on the induced

draught fan

What is HASLE® ISOMEMBRANE®?

The ISOMEMBRANE® is a flexible, elastic, ash- and gas tight sealing, based on a special

combination of mainly refractory materials.

The HASLE ISOMEMBRANE® is a sandwich-type construction. It consists of an ISOMASK

made by layers of specially designed high density ceramic fibre, a special metal lattice, or

mesh. Between the layers HASLE's ISOFIX High Temperature Adhesive is applied. The

combination of the ISOMASK, ISOFIX and expandable metal is finally coated with a high

temperature HASLE® CS1500 castable, to ensure a durable surface. (Please see separate

section on the safe use of ceramic fibres).

The HASLE ISOMEMBRANE® can be installed in many shapes according to the actual need of

the different sealing areas. It can be fixed to any clean surface by welding, casting or gluing.

The HASLE ISOMEMBRANE® has proven its excellence for two decades. The technology has

been applied to both gas- and coal fired power plants in Sweden, Denmark, UK, Australia,

USA and China.

The HASLE ISOMEMBRANE® was applied in the 1980's on most of the Danish utility boilers

and in the 1990's in the UK. In the USA the ISOMEMBRANE® has been applied to several

hundred power plants during the past 20 years. In China the technology has been used in the

past 15 years.

The HASLE ISOMEMBRANE® is today considered the most advanced and efficient way of

boiler top dead space sealing. It can be applied for retrofitting older PF-fired boilers or as a

construction demand in new boilers, and with an expected lifetime expectancy of more than

10 years, the installation will ensure a positive return on invest. Regardless whether applied in

new or existing boilers.

HASLE has its own certified installation team, which is able to undertake any installation task

worldwide. A Supervisor ensures that the material and installation quality is always at the

same high standard.

The HASLE ISOMEMBRANE® technology is a Danish invention, which is developed by- and is

the property of HASLE Refractories A/S . No-one else in the world has demonstrated a similar

economical and flexible solution to the difficult problem of boiler top dead space sealing.

References

HASLE ISOMEMBRANE® has been applied to several hundred power plants all over the world. Please find selected references in the list below.

Power plant Job description

I/S Fynsvaerket DK-5000 Odense Denmark

Complete turbine insulation boiler no.5 & 6

Stigsnaesvaerket SEAS DK-4230 Skaelskør Denmark

Sealing against fly ash in boiler top, boiler no. 2

I/S Vestkraft DK-6700 Esbjerg Denmark

Complete sealing against fly ash in boiler roof block 1 & 2 and complete dry turbine insulation 200 MW

Nordkraft DK-9000 Aalborg Denmark

B&W boiler no. 5 sealing against fly ash

Oeresundsverket Malmoe Sweden

Sealing against flue gas fired leakage in a coal fired Steinmüller boiler (200 MW)

National Power Tilbury Power Station UK

Top dead-space sealing on power plant boiler. Unit no. 10, 350 MW Top dead-space sealing on power plant boiler. Unit no. 9, 350 MW

National Power Eggborough Power Station UK

Top dead-space sealing on power plant boiler. Unit no. 2, 500 MW

National Power Thorpe Marsh Power Station UK

Top dead-space sealing on power plant boiler. Unit no. 2, 500 MW

National Power Tilbury Power Station UK

Top dead-space sealing on power plant boiler. Unit no. 8, 350 MW

National Power Aberthaw Power Station UK

Top dead-space sealing on power plant boiler. Unit no. 7, 500 MW

Due Power Marshall North Carolina USA

Penthouse

CP&L Mayo Plant North Carolina USA

Precipitator

Tennessee Eastman no.24 Tennessee USA

Penthouse

Duke Power Plant Marshall North Carolina USA

Expansion Joints

Duke Power Dan River North Carolina USA

Expansion Joints

DP&L JM Stuart Ohio USA

Penthouse

Duke Power Plant Allen North Carolina USA

Precipitator

Tennessee Eastman no.18 Tennessee USA

Rear Wall

CP&L Lee Plant North Carolina USA

Economizer

Duke Power Cliffside North Carolina USA

Expansion Joints

Panxian no.2 Guizhou China

Penthouse

Yaxi no.4 Guizhou China

Penthouse

Shidongkou no.4 Shanghai China

Penthouse

Zhangze no.6 Shanxi China

Penthouse

Yuanbaosan no.1 Liaoning China

Penthouse

Yuanfu no. 2 Guangdong China

Penthouse

International Power Hazelwood Power Station Australia

Penthouse and tubes

Please feel free to contact the undersigned for any query or clarifications ……

RUPAM ADHIKARI Manager-Sales & Supports HASLE Refractories India Pvt. Ltd 4th Floor, K S R Tower, High Tech City Main Road, Madhapur HYDERABAD-500081 _____________________________________ Tel/Fax: + 91 40 4220 5001 Mobile No: + 91 9949013794 E-mail: ra@hasle-refractories.com Web: www.hasle-refractories.com