Project Report

PENNGUARD® Block Lining System

PROTECTING POWER

PLANT CHIMNEYS

Coal fired power station in the western

United States prepares its four chimneys

for wet stack operation by installing

Pennguard®

linings in the brick flues.

The San Juan Generating Station near the town of

Farmington, New Mexico is a mine mouth power station

with an installed capacity of 1,800 MW. Its four boilers,

two of 350 MW and two of 550 MW each, fire coal with a

sulfur content of 0.9 %. The power station has operated

FGD plants for many years and it will now move to

desulfurizing one hundred percent of its exhaust

gas flow.

In the mid seventies, the San Juan Station was fitted

with FGD plants using the Wellman Lord process.

This early FGD system used four separate scrubber

vessels per unit. In the late nineties, the FGD system

was converted to a wet limestone process, upgrading

the sulfur removal efficiency from 75 % to 90 %.

The power station continued to bypass a portion of

the gas stream around the FGD system.

Key facts about

San Juan Power

Station

2 x 350 MW and 

2 x 550 MW coal 

fired power station

Wet FGD on all 

four units

No flue gas reheat

All four existing

chimneys with brick

flues to be lined with

Pennguard®

Through the years of operating the San Juan

chimneys with a mixed, partially desulfurized gas

flow, it was found that the free standing brick

chimney flues were subject to degradation especially

in the mixing zones for treated and non-treated gas

flows. In 2002 and 2003 the station installed

Pennguard® linings in the lower part of the brick flues

of the Unit 1 and Unit 2 chimneys.

With emissions regulations becoming more and

more stringent, the San Juan Power Station, which is

operated by Public Service of New Mexico but which

is owned by nine utilities from five states, decided

in 2006 to switch to fully desulfurized operation,

eliminating any bypass around the FGD system.

In order to prepare the chimneys for low temperature

wet stack operation, the owners also decided that the

brick flues in all four chimneys would be protected by

Pennguard® linings over their full height.

San Juan

Power Station 

Pennguard® is a registered 

trademark of Ergon Asphalt 

& Emulsions, Inc.
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Unit 4 chimney prepared 

for wet stack service

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1. In the most recent environmental upgrade at 

San Juan Power Station, the Unit 4 chimney

with 27,375 ft2 of brick flue surface was the

first one of four chimneys to be lined with

the Pennguard®

Block Lining System.

The chimney contractor, Pullman Power, had

to complete the lining of the brick flue and

all related works in an outage of 6 weeks,

during the third quarter of 2007.

2. Before installing the Pennguard®

lining, the

brickwork was power washed and then grit

blasted to remove all dirt, deposits and other 

loose particles. 

3/4. It is normal for brick flues to show some

offsets between the individual bricks.

The Pennguard®

lining can accommodate

most of these surface irregularities by 

using a thicker adhesive back joint. 

5. Narrow, stable cracks, caused by settling of

the brickwork or thermal shocks, can usually

be covered by the Pennguard® Block Lining

System without additional preparation.

6/7. After grit blasting and application 

of the Primer onto the brick surface 

(picture 6), liquid collection gutters were 

installed into the chimney (picture 7). 

Alden Research Laboratory and Pullman 

Power designed a liquid collection system 

for each of the four chimneys.

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Installation process

summarized:

Installing work platform

Cleaning and grit blasting

brick substrate

Brickwork repairs

Primer application

Liquid collection system

installation

Pennguard® lining 

installation

Finishing works including

false floor installation

The similar Unit 3 chimney was the second chimney to be lined and was successfully

completed as well, in a 6-week outage, during the first quarter of 2008. The applications

in the Unit 1 and Unit 2 chimneys are scheduled in the third quarter of 2008 and the first

quarter of 2009. The combined surface area of all chimney flues to be lined is 87,445 ft2

.

8/9. The Pennguard® Blocks are applied to the brick

substrate using the Pennguard®

Adhesive Membrane.

The Pennguard® lining installation crew consisted of

installers, who were supported by helpers on the

platform as well as on ground level. The typical

installation productivity is 15 to 21 ft2 per installer per

hour. All the work, including surface preparation,

installation of the liquid collection system, lining

application and construction of a false floor was

completed within the 6-week outage. 

One project, four chimneys
Hadek Protective Systems, Inc., Foster Plaza 5, 651 Holiday Drive, Pittsburgh, PA 15220

Tel. 412-204-0028 Fax. 412-204-0039 E-mail: sales@hadek.com Web: www.hadek.com

Pennguard®linings are the 

most effective technology

Ever since the introduction of FGD plants, owners

have decided to re-use their existing, brick lined

chimneys for low temperature, acid condensing

operation. Brick flues have been prepared for

agressive FGD operating conditions in various ways

and Pennguard® linings have proven to be the most

effective, durable technology.

Why?

A positive barrier

A lightweight, impermeable Pennguard® lining will

form a positive barrier, isolating the brick flue from

any contact with acidic flue gas and condensate.

Picture 1 shows the outside of a brick flue that was

internally lined with Pennguard® and then placed 

in wet stack service. Picture 2 shows the outside 

of a brick flue that was left unprotected except for

pressurizing the annular space, and then placed in

wet stack service.

No anchors, no supports

A Pennguard® lining is lightweight and fully bonded

to the brick substrate by its adhesive. It does not

require any anchors or supports that could lead

condensate into the lining and create weak spots 

as a result of corrosion.

Flexible and adaptable

By their nature, most brick flues have irregularities

such as bulges, offsets between bricks and narrow

cracks. Thanks to the limited size of Pennguard®

Blocks and the flexibility of its adhesive, 

a Pennguard® lining will readily adapt to most 

of these irregularities. 

Converting brick flues for low

temperature FGD service

With the four chimneys at San Juan Generating

Station included, Pennguard® linings have been

successfully installed in well over 30 brick flues in

power stations worldwide.

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