### RE: High Desert PSD

Boyer, Jon

to:

Anita Lee

04/25/2008 03:43 PM

Show Details

History: This message has been replied to.

Anita,

Attached in the table below is some data regarding steam temperatures and the major steps taken during the startup. I’ll

add some description below. Combustion Turbine (CT ) and Steam Turbine Generator (STG) load is taken f rom the Data

Acquisition and Handling System (DAHS), while the 1 st Stage Inner Metal Temperature is taken from the pl ant Data Control

System (DCS). I changed the times from DCS to matc h those from the DAHS, since the DCS computer is an hour and 10

minutes off due to daylight savings and a time diff erence between the computers.

Note that when we started CT3 at 10:14, the 1 st stage inner metal temperature is 95 degrees F. Th e desirable prewarming

rate for the inner metal temperature is 90 degrees F per hour until it reaches 300 degrees F, accordin g to the Toshiba STG

startup procedure. However, the rate of increased due to the potential restrictions on startup durati on. Action Date/Time UNIT0001

CTLOAD

Value UNIT0002

CTLOAD

Value UNIT0003

CTLOAD

Value STLOAD

Value Ist Stage

Inner

Metal

Temp (F)

CT3 START 2007-10-25 10:14 AM 0.0 0.0 0.0 0.0 95.0

Prewarming STG ends/ Begin STG

Accelleration 2007-10-25 11:36 AM 0.0 0.0 30.1 0.1 282.3

Trip on CT2 Cold Start 2007-10-25 1:44 PM 0.0 0.0 39.9 0.1 603.3

CT3 Shutdown Begins 2007-10-25 2:00 PM 0.0 0.0 65.2 0.0 651.6

Re-START on CT2 (HOT) 2007-10-25 2:06 PM 0.0 0.0 53.4 0.0 668.8

CT3 Shutdown Complete 2007-10-25 2:58 PM 0.0 54.3 1.2 0.3 680.0

STG Online/ @ 0MW to initial load 2007-10-25 3:04 PM 0.0 55.3 0.1 5.8 683.0

CT2 In Compliance 2007-10-25 3:40 PM 0.0 115.1 0.0 9.3 780.0

Restart on CT3 2007-10-25 3:52 PM 0.0 115.1 0.0 9.3 806.9

CT3 in Compliance 2007-10-25 5:45 PM 0.0 112.9 114.1 131.5 1009.0

CT1 Start 2007-10-25 11:43 PM 0.0 149.5 151.7 160.7 1008.0

CT1 In Compliance/Startup

Complete 2007-10-26 1:23 AM 114.3 114.4 114.8 200.8 1000.0 

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...Once the STG acceleration begins, the STG is accele rated to several different stages by approximately 120 rpms per

minute. The STG is increased to 400, 800, and 3600 rpm. Following these rpm increases, there are hol ding periods to

allow for a heat soak. The timing of these events can be delayed due to the starting and stopping of different CTs. Once

the STG was brought online, it is increased to 3 pe rcent load and held there for approximately 50 minu tes. We used the

Hot Start on CT2 to accomplish this. The subseque nt starts on CT3 and CT1 was then used to bring the STG up from the

initial load.

As you can see, in order to meet the current permit requirements, we must amend the startup procedures to account for the

potential lack of time during startups. We also ha ve to spend additional time in starting, shutting d own, and switching units

which assist in bringing the STG up to load. If uni t trips on cold start did not place the CTs into a hot classification via

permit, then that would alleviate some of the need to bounce units. If we could use one CT to warm th e STG, that would

smooth the process we use to bring the units online , without any increase in emissions.

Please let me know how I can be of further assistan ce or answer any further questions. If you would l ike to visit the plant, I

can arrange for myself and some of the operations s taff to be here to give you an overview and answer any questions in

person as well.

Jon Boyer

Senior Environmental Scientist

High Desert Power Project

(760) 530-2303 (office)

(760) 912-3007 (cell)

From: Lee.Anita@epamail.epa.gov [mailto:Lee.Anita@epamai l.epa.gov]

Sent: Tuesday, April 22, 2008 9:36 AM

To: Boyer, Jon

Subject: High Desert PSD

Hi Jon,

Thanks for sending over the information and for our discussion today. As you suggested, I'm including my specific

questions in an email, so here they are:

1. Regarding Table 1 in the letter, I'm wondering i f you have some STG temperature information availab le - rather than the

more labor intensive time series of STG temperature , would it be easier to pick out times and just not e what the STG

temperature was?

Specifically, it would be useful to know the STG te mperature for 10/25/07 for 10:14, 13:44, 14:00, 14: 06, 15:52, and 23:43.

And what is the temperature when startup is conside red complete? When steam is introduced into the STG (265-300

degF), or when the SCR is at 464 deg F?

2. My understanding is that after Turbine 2 tripped , upon restart of Turbine 2, if it had a Cold Start duration limit, Turbine 3

would not have had to be shutdown and restarted. Wo uld this be true if Turbine 2 had a warm start dura tion limit (2.6 hours)

instead of a cold start limit (4.5 hrs) upon restar t after trip? (If we define cold/warm/hot starts by STG temperature,

depending on the temperature of the STG at 14:06 (w hen Unit 2 was restarted), it may be classified a " warm" start, if so, is

that sufficient to avoid having to shutdown Unit 3? )

3. Temperatures on page 25 of Toshiba manual (#6) - is it appropriate for conditions at HDPP to use th ose 3 STG

temperature ranges to define cold/warm/hot start (r ather than using a time since last firing of CTGs)? Or are the various

temperatures presented in the letter (265/300 deg F , 170/235 deg F) more appropriate for HDPP?

Thanks Jon. Please let me know if any of these ques tions are not clear - it's a little challenging to describe!

Anita

........................... US Environmental Protection Agency 

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...Region 9, Air Permits Office

75 Hawthorne Street (AIR-3)

San Francisco, CA 94105

ph: (415) 972-3958

fax: (415) 947-3579

........................... 

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