This relates to the nitric acid plant, taken from Y-S AQMD Breakdown Reports. From Jan 2007 through Feb 2010 List excludes CEMS breakdowns. Relates to Nitric Acid Plant operations only Correspondence log ENV: Start End Duration 07-012 2/6/2007 13:47 2/6/2007 15:15Intermittent 07-013
07-054 8/3/2007 5:45 8/3/2007 6:07 00:22 None estimated, Plant shut down to fix the problem. 08-016 1/26/2008 15:23 1/26/2008 15:26 00:03 None estimated, Plant shut down to fix the problem. 08-017 2/5/2008 10:35 2/5/2008 10:40 00:05 None estimated, Plant shut down to fix the problem.
08-033 4/3/2008 8:00 4/3/2008 8:03 00:03 08-034 4/7/2008 12:15 4/7/2008 12:20 00:05

08-035
08-038 4/15/2008 14:424/15/2008 15:00 00:18

08-086 9/11/2008 7:25 9/11/2008 7:40 00:15 08-098 10/9/2008 2:02 10/9/2008 2:30 00:28
08-117 12/18/2008 10:2512/18/2008 10:27 00:02
08-119 12/20/2008 11:5012/20/2008 11:55 00:05 09-031 4/7/2009 6:37 4/7/2009 6:49 00:12 09-032 4/9/2009 7:33 4/9/2009 7:40 00:07 09-033 5/2/2009 6:15 5/2/2009 6:20 00:05

09-042 5/26/2009 10:175/26/2009 10:20 00:03 09-048 09-082 9/30/2009 12:379/30/2009 12:39 00:02 09-104 11/25/2009 7:55 11/25/2009 8:05 00:10 10-001 1/3/2010 8:07 1/3/2010 8:12 00:05Plant Trip, power trip 

### Agrium US Inc Sacramento Nitrogen Operations Malfunctions Summary
Short Description

Ammonia release from E-601 PSV & Plant Trip Update to above NG Compressor to Decomposer trip Plant Trip, power trip Visible Plume Plant trip Plant Trip, power trip Plant Trip, power trip Plant Trip, power trip Clearing Compressor Train after plant was tripped for converter inlet overheating
Power Trip CEMS stopped logging Plant Trip, high mix gas temp Plant trip, fuse blown Plant trip, instrument failure NG Compressor to Decomposer trip Plant Trip, unknown cause

Update to above NG Compressor to Decomposer trip correction to above NG Compressor to Decomposer trip Natural Gas Compressor failure



### No change to NOx information None estimated. Plant brought back under control. None estimated. Plant secured. None estimated. Plant secured. None estimated. Plant secured. None estimated. Plant secured. None estimated. Plant secured.

None estimated for NOx. None estimated. Plant secured. No excess emissions anticipated. Plant shut down & secured. Plant had been running in steady state and at reduced rates at the time of the trip. No excess emissions anticipated. Plant shut down & secured. Plant had been running in steady state and at reduced rates at the time of the trip. None estimated. Plant brought back under control. None estimated. Plant secured.

None estimated. Plant secured.

The compressor was re-started and the decomposer brought back to stable temperatures. Operators secured the Plant and stopped the plume. Operators secured the Plant and stopped the plume. Operators secured the Plant and stopped the plume. Operators secured the Plant and stopped the plume. Operators secured the Plant and stopped the plume.

Steam feed valve taken of automatic and remotely manually closed. Plant secured.
Nitric Acid Plant tripped out due to a PG&E power failure. This resulted in a light visible plume of approximately 10minutes duration. Nitric Acid Plant tripped out due to a PG&E power failure. This resulted in a visible plume of approximately 5 minutes duration. The compressor was re-started and the decomposer brought back to stable temperatures. Engineering staff are investigating the improvement of the alarm systems to better warn of such a trip. Operators secured the Plant and stopped the plume.

As the compressor cleared the lines, the NOx subsided. No visible emission was evident after approximately 1⁄4 hour. The Nitric Acid Plant was taken down at approximately 07:40 pending return of power and proper functioning of the CEMS Data Historian. Operators secured the Plant and stopped the plume. Secured Plant to stop visible emission. Secured Plant to stop visible emission.

Instrumentation wire came loose causing loss of pressure signal from E601 ammonia heat exchanger. This resulted in a command for the steam feed valve to the exchanger to open, causing an increase in heat and ammonia pressure. The Pressure Relief Valve PSV 687 at the exchanger subsequently opened (chattered). The increased pressure of ammonia vapor fed additional ammonia to the gauze which ultimately caused the Plant to trip on high temperature with a resulting slight visible plume. The natural gas compressor supplying the decomposer tripped out causing a visible plume from the Plant stack. This caused a visible plume of less than 2 minutes duration Plant tripped causing a visible plume for less than two minutes. This was caused by a fuse on the high voltage line failing. The reason for this is unknown at the time of this report. Plant tripped causing a visible plume for between two and five minutes. This was caused by an interruption in PG&E supply. Nitric Acid Plant tripped out due to a PG&E power failure. This resulted in a visible plume of approximately 5 minutes duration. Nitric Acid Plant tripped out due instrumentation spike tripping natural gas compressor and sending false gauze temperature indication. This resulted in a visible plume of approximately 5 minutes duration. Nitric Acid Plant tripped because of high mix gas (prior to the gauze) temperature. This caused a visible plume. Instrumentation failure causing the plant to trip Repair/replace failed instrument Plant personnel were switching cooling water pumps for planned maintenance purposes. The natural gas compressor supplying the decomposer tripped out on low cooling water pressure. This caused a visible plume of approximately 3 minutes duration. Nitric Acid Plant tripped out for unknown reason. This caused a slight visible plume of approximately 5 minutes duration.

Nitric Acid Plant tripped out due to a PG&E power failure. This resulted in a visible plume of approximately 2 minutes duration. Natural Gas compressor supplying gas to the decomposer tripped out four times resulting in three minor visible plumes of short duration. This was determined to be caused by a bad trip switch. Switch has been jumpered out until replaced. Compressor running continuously

The cause was found to be related to temperature settings. The main process air compressor has two turbines that power it; a steam side and decomposer-discharged heat expander side. At the expander inlet, temperatures rose to 926degF & to 912degF. It was found that the unit was set to trip at 900degF. The trip temperature was adjusted to 1,000degF. The high temperature alarm set-point was also reduced from 940degF to 900degF. The inlet piping to the Converter was found to be red-hot. Consequently the Plant was tripped. In the process of subsequently clearing the lines for Maintenance (by rolling the compressor) NOx was released out of the stack. Power to the Administration Building and the Ammonia Storage areas of the Plant was interrupted. The Nitric Acid Plant continued to run but ammonia supply to the Plant was also interrupted. The Data Historian that logs CEMS data also went down (located in the Administration Building). None anticipated. The acid plant was taken down. Cause of Breakdown 

### None estimated, Plant running under reduced rates Corrective Measures Taken 

### An electrical failure in a cooling tower pump caused a cascading effect resulting in the natural gas compressor supplying gas to the decomposer tripping out and would not re-start. This resulted in a visible plume of approximately four minutes duration. Estimated (Excess) Emissions During Breakdown Condition



### Natural Gas Compressor failed and would not restart. Tripped out the plant. Release duration was three minutes. Plant is down for planned maintenance outage. GC604 will be examined for failure source and Plant was shut down.