Bachman, Tom A.

From:

Sent:

To:

Subject:

Tom,

John Graves [jgraves@minnkota.com]

Wednesday, March 24,20108:34 AM

Bachman, Tom A.

Use of Confidential Information

Haldour Topsoe has agreed to the use oftheir information as you previously described.

John T. Graves, P.E.

Environmental Manager

Minnkota Power Cooperative, Inc.

P.O. Box 13200

Grand Forks, N.D. 58208-3200

Tel: (701) 795-4221

Fax: (701) 795-4214

1
HALDOR TOPSOE, INC.

Catalyst Division

Houston, TX

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CONFIDENTIAL In accordance with Air Pollution Control Rules

for the State of North Dakota at 33·15·01·16

October 12, 2009

Page 5 of 30

HTI Quotation No. 09-6362

3.3 Catalyst Specification, Exceptions & Offer

Based on the current data available, including the Microbeam Technologies report dated August

20, 2009, HTI believes that the low dust (after ESP) option is the most viable. HTI feels that

deactivation of the catalyst due to alkali poisoning (sodium) will be the biggest challenge.

However, with that said, HTI also recognizes that chemical deactivation can generally be

managed with the adjustment of catalyst volume and/or· guarantee life while the potential exists

that physical deactivation due to catalyst blinding and pll:lgging could be severe enough to make

SCR a non-viable option for controlling NOx emissions.

The absence of S02 downstream of the FGO has been discussed and the effect it might have on

physical deactivation of the catalyst due to blinding. Considering that most of the calcium will be

removed in the ESP, calcium sulfate formation should be minimal. Also, considering the low

operating temperature of the SCR (-600F) chemical poisoning of the catalyst affects the

observed activity much more than does physical poisoning (blinding) of the catalyst. The tail-end

option should be considered further with actual slip stream or mini reactor testing on an operating

unit but at this time HTI feels that with the data currently available that the low dust option is the

best option available.

HTI's main concern in relation to the lignite fuel is the content of alkali metals (sodium in the case

of NO lignite) which leads to chemical poisoning of the catalyst by reacting with the vanadium

active sites. The deactivating effect of sodium (and potassium) will be the same, whether in the

form of oxide, Sulfate or another salt. The deposition rate of the aerosols could be different,

though, depending on whether they are in the form of oxides or sulfates due to differences in

mobility.

Information contained herein is confidential and may not be used by or conveyed to any third party without our written authorisation· Haldor Topslle AlS

· Bachman, Tom A.

From:

Sent:

To:

Subject:

Tom"

John Graves Ugraves@minnkota.com]

Wednesday, March 17, 20109:22 AM

Bachman, Tom A.

Minnkota BACT - Use of Confidential information

CERAM will allow the use ofseveral paragraphs from their October 13, 2009 proposal in your analysis of our

recent BACT submittals. Specifically they will allow the use ofthe material on Page 3, paragraphs 2, 3 and

5(which continues on page 4) beginning with "The high levels....." and ending with" ...calcium oxide present

in the flue gas."

John T. Graves, P.E.

Environmental Manager

Minnkota Power Cooperative, Inc.

P.O. Box 13200

Grand Forks, N.D. 58208-3200

Tel: (701) 795-4221

·Fax: (701}795-4214

1
CERAM -------_ CATALYSTS + HONEYCOMSS

....

Minnkota Power Cooperative

Attn. Mr. Luther Kyemen

Milton R. Young Station Units 1 & 2

1822 Mill Road

Grand Forks, ND 58208-3200

CERAM Environmental, Inc.

Porzellanfabrik Frauenthal GmbH

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CONFIDENTIAL

In accordance with Alr'Poliutlon Control Rules

for the State of North Dakota at 33·15-01·16

October 13,2009

7304 W. 130th Street Suite 140. Overland Park, Kansas 66213

Tel: (913) 239-9896. Fax: (913) 239-9821
Minnkota Power Cooperative

M.R. Young Station

Boiler Type and Fuel Analysis

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October 13,2009

Page 3

The levels of K20 in the ND lignite ash are in the high end range found in many biomass fuels,

such as wood and switch grass. However; the levels ofNa20 are much greater than that found in

biomass or coal fired SCR applications. Different boiler types will affect deactivation.

CERAM's experience with biomass applications that utilize a bubbling fluidized bed (BFB)

boiler with the SCR in a high dust arrangement have been successful because we were able to

size the catalyst appropriately and take advantage of the lower flame temperature (e.g., less

oxidized poisons), available sorbent (e.g., limestone) that can absorb a portion of the catalyst

poisons and the fact that a large portion ofthe ash is entrained. Pulverized coal (PC), stoker and

cyclone boilers in the high dust arrangement can lead to an increase in deactivation due to the

higher local flame temperatures and areas of incomplete combustion that both can lead to a

severe increase in oxidized poisons. Solutions to reduce catalyst deactivation have been to use

low dust (e.g., catalyst downstream of a baghouse with sorbent injection) and tail end (e;g.,

downstream baghouse and scrubber) configurations. However, our experience on low dust and

tail end biomass and incinerator applications with similar fuel characteristics have shown that

increased deactivation will still occur compared to similar applications firing sub-bituminous and

bituminous coals.

The high levels ofNa20 in the ash for the ND lignite are not commonly found in sub-bituminous

and bituminous coals which are fired with SCR systems~ CERAM is unaware of any SCR

application experience in the industry with this level and form ofsodium in the ash. Sodium is a

well known catalyst poison. In particulate form the effects of sodium can be controlled by

maintaining warm and dry conditions on the catalyst at all times during layup. Allowing moist

conditions on the catalyst will result in the particulate bound sodium leaching into the pore

structure of the catalyst where catalyst poisoning will occur. Small aerosol particles can

penetrate and neutralize active catalyst sites even in dry conditions.

Catalyst Deactivation

For this application we can assuinethat most of the ash will be removed; however catalyst

deactivation will still occur due to gaseous constituents in the flue gas and from the small amount

of ash that will reach the reactor. Even though this application maybe ether a low dust or tail

end application it is not a "no dust" application. Deactivation can be caused by exposure to

various catalyst poisons and fouling agents, such as alkaline metals, arsenic, sulfate compounds,

CONFIDENTIAL
Minnkota Power Cooperative

M.R. Young Station

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October 13,2009

Page 4

silica and phosphorous compounds, hydrochloric and hydrofluoric acids, sodium and potassium

in the ash, etc., that are formed during the combustion process. Catalyst installed in even low

dust and tail end locations are poisoned from the exposure to the flue gas. Some of the potential

catalyst poisons that could lead to deactivation of our catalyst are found in the mineral and trace

analysis or can be controlled by temperature. The amount of sulfur dioxide, sulfur trioxide and

sulfuric acid are a function oftemperature, thereby ifthe temperature is controlled above the acid

dew point then no problems should exist. In addition, the amount of lead, mercury, chromium

and other metals listed in the trace analysis are typically extremely low and should not bea

major influencing factor for a coal fired application. Moreover, the high levels of phosphorous,

sodium and potassium found in the mineral analysis will increase deactivation rates. Arsenic

poisoning will occur, however the levels for which this can he attributed to are a function of the

amount of calcium oxide present in the flue gas.

\,

CONFIDENTIAL