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 from the Data 

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

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

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

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

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

startup procedure. However, the rate of increased due to the potential restrictions on startup duration. 

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 accelerated 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 holding 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 percent load and held there for approximately 50 minutes. We used the 

Hot Start on CT2 to accomplish this. The subsequent 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 have to spend additional time in starting, shutting down, and switching units 

which assist in bringing the STG up to load. If unit 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 the 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 assistance or answer any further questions. If you would like to visit the plant, I 

can arrange for myself and some of the operations staff 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@epamail.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 if you have some STG temperature information available - rather than the 

more labor intensive time series of STG temperature, would it be easier to pick out times and just note what the STG 

temperature was? 

Specifically, it would be useful to know the STG temperature 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 considered 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. Would this be true if Turbine 2 had a warm start duration limit (2.6 hours)

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

depending on the temperature of the STG at 14:06 (when 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 those 3 STG 

temperature ranges to define cold/warm/hot start (rather 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 questions 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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