- Sequoyah Nuclear Plant experienced high dissolved oxygen levels in the secondary plant on both units due to a misalignment of the demineralized water sample system. Demineralized water was being sampled instead of condensate, causing dissolved oxygen readings over 100 ppb.
- It took chemistry staff time to recognize the sample system was drawing demineralized water instead of condensate. Once this was identified and the demineralized water pressure regulators were adjusted, normal dissolved oxygen readings were restored.
- Lessons learned include maintaining clear communications during system changes, capturing all knowledge into procedures to prevent reliance on tribal knowledge, and improving system design to prevent similar sample misalignments.
This is the an excerpt for a process description of my 2010 AICHE National Student Design Competition Report. Note the detail in the piping and instrumentation diagrams coupled with the process description.
The Claus process is the industry standard and so the most
significant gas desulfurizing process, recovering elemental sulfur
from gaseous hydrogen sulfide.
The process is commonly referred to as a sulfur recovery unit
(SRU) and is very widely used to produce sulfur from the
hydrogen sulfide found in raw natural gas and from the by-product
sour gases containing hydrogen sulfide derived from refining
petroleum crude oil and other industrial facilities.
There are many hundreds of Claus sulfur recovery units in
operation worldwide.
In fact, the vast majority of the 68,000,000 metric tons of sulfur
produced worldwide in one year is by-product sulfur from
petroleum refining and natural gas processing plants.
This is the an excerpt for a process description of my 2010 AICHE National Student Design Competition Report. Note the detail in the piping and instrumentation diagrams coupled with the process description.
The Claus process is the industry standard and so the most
significant gas desulfurizing process, recovering elemental sulfur
from gaseous hydrogen sulfide.
The process is commonly referred to as a sulfur recovery unit
(SRU) and is very widely used to produce sulfur from the
hydrogen sulfide found in raw natural gas and from the by-product
sour gases containing hydrogen sulfide derived from refining
petroleum crude oil and other industrial facilities.
There are many hundreds of Claus sulfur recovery units in
operation worldwide.
In fact, the vast majority of the 68,000,000 metric tons of sulfur
produced worldwide in one year is by-product sulfur from
petroleum refining and natural gas processing plants.
Presentation developed for SubseaSurvery IRM. Detailing methodology for the assesment of blockages in subsea pipelines. Presented by Fernando Hernandez for Wrights Well Control Services.
NSPS Subpart OOOO: Applicability and Compliance BasicsAll4 Inc.
Roy Rakiewicz of ALL4 Inc, presents "General Applicability of NSPS Subpart OOOO: Applicability and Compliance Basics". The presentation provides detailed information on: affected facilities, rule structure, storage vessel affected facilities, and gas well affected facilities.
A recent study conducted by an independent environmental laboratory proves that TIGG’s 5DC 12 x 30 activated carbon is effective at removing TTHMs from municipal drinking water. The test was sponsored by a municipality that needed to come into compliance with the EPA’s DPB Stage 2 regulations.
The study sponsor historically had high levels of TTHM in its water that ranged between 105 and 171 µg/L. The municipality talked to TIGG about a water purification adsorption system. While some in the industry insist that coal-based activated carbon is the only effective means of removing disinfection byproducts from municipal drinking water, TIGG experts recommended their 5DC 12 x 30 virgin coconut activated carbon.
The municipality had an independent laboratory run a pilot study using a rapid small-scale column test. They used TIGG’s 5DC 12 x 30 NSF activated carbon, which is designed to remove low concentrations of contaminants from potable water. The laboratory found that initial TTHM concentrations of 138 µg/L were reduced to < 1.0 µg/L following treatment with virgin coconut activated carbon. Based on the scale-up of the testing, it was determined that a full scale carbon adsorber would effectively treat TTHMs for 325 days before the bed needed a changeout.
Not only is coconut-based activated carbon effective, it is typically more economical than coal-based activated carbon. The following report shows the laboratory’s results over a 24-day period.
Wright’s Well Control Services (WWCS) performed a hydrate remediation in the Gulf of Mexico at 7,200’ water depth from a proprietary skid containing a pump and motor. This self-contained subsea unit is powered from the surface through coiled tubing from a Multi-Service Vessel (MSV). Not limited by a Remotely Operated Vehicle’s (ROV) hydraulic energy, the subsea pump can increase volume up to 1 bpm, or reverse flow drawing pressure down to a sub-ambient -12 psi. For this project the integrated skid cleared 15 miles of 12” pipeline removing 9,000 barrels of hydrocarbons, condensate, gases and other fluids.
For a subsequent job, a paraffin and asphaltene blockage mixed with hydrates was successfully mitigated reopening four miles of pipeline. To date the skid has cleared a total of 30 miles of pipeline.
WWCS Gas Separator - Engineered to Prevent Hydrate Blockages within the Skid and its Coiled Tubing
A unique WWCS gas separator sits atop the skid and removes the gas mixed in the hydrate to the surface. This approach prevents the formation of additional hydrates in the coiled tubing outtakes used by both the gas separator and the pump for the remaining fluids. The old technique required returning the coiled tubing to the surface for thawing each time hydrates formed and reconnecting to the subsea pump–causing costly delays.
This system is further protected from hydrate blockages between the pipeline end termination/flowline end termination and the skid by injecting dispersant chemicals from a ROV panel as needed.
Engineered by WWCS to Ensure Safety
WWCS has engineered in a triple-redundant safety system to compensate for a loss of dynamic positioning (DP) or drive-off by the MSV from which the hydrate skid is deployed. An emergency quick disconnect (EQD) removes the skid’s coiled tubing connections via four hot stabs. Accumulators provide an isolated source of hydraulic power for the EQD which can be activated acoustically from the vessel, with ROV manipulators, or as a last resort with wire ropes. This safety system eliminates potential damage to the pipeline asset from the hydrate skid dragging across the seabed or thousands of feet of coiled tubing crashing down on the remediation site.
Engineered by WWCS to Protect the Environment
The skid has a number of environmentally friendly features. The pump is powered by filtered sea water avoiding any adverse impact from leaking or severing of the coiled tubing. The fluids the hydrate pump sends to the surface are contained in a specially designed tank on the deck of the MSV. Lastly, in the event of a MSV drive-off or loss of DP, emergency shut-off valves minimize the release of any hydrocarbons from the coiled tubing outtakes after an EQD. WWCS is currently developing a flush loop to eliminate any hydrocarbon release from an EQD deployment.
Shallow and Inland-Water Capabilities
The WWCS Hydrate Remediation System is also the solution of choice for shallow and inland-water pipelines. Depending on the
DAMMAM SECOND INDUSTRIAL CITY - IPS REHABILITATION WORKSIslam Nassef
Design capacities of the lift station
approximately 1670 m3/h. The
GWC’s initial goal for this project
is to develop a prioritized list of
repair/refurbishment projects based upon a comprehensive condition assessment and criticality analysis of IPS lift station planned to remain in operation.
Australasian Lab managers Conference: Gas Generation Dr Nicole Pendini 2019Nicole Renee Pendini
This presentation focus on on-site Gas Generation for the laboratory space supplying a range of analytical and specialty applications within the lab environment. I will focus on keeping green by preventing weekly cylinder and bulk supply deliveries, that waste energy offsite to generate the gas and petrol to delivery to the laboratory. The overall cost savings vs other methods (ROI < 1.5 years including service) and of course how Laboratory managers can significantly reduce their OHS/E risk with onsite Nitrogen, Hydrogen and Zero Air gas generators.
Enoc martinez el lazo y_el_abrazo-12187Costa_afuera
Enoc Martinez: Los lazos son tan sencillos y bonitos, que hasta pueden ser comparados con el amor, el cual une a las personas también con "lazos" y de todo tipo, lazos de amor, amistad, hermandad.. Nunca sueltes estos lazos!
Presentation developed for SubseaSurvery IRM. Detailing methodology for the assesment of blockages in subsea pipelines. Presented by Fernando Hernandez for Wrights Well Control Services.
NSPS Subpart OOOO: Applicability and Compliance BasicsAll4 Inc.
Roy Rakiewicz of ALL4 Inc, presents "General Applicability of NSPS Subpart OOOO: Applicability and Compliance Basics". The presentation provides detailed information on: affected facilities, rule structure, storage vessel affected facilities, and gas well affected facilities.
A recent study conducted by an independent environmental laboratory proves that TIGG’s 5DC 12 x 30 activated carbon is effective at removing TTHMs from municipal drinking water. The test was sponsored by a municipality that needed to come into compliance with the EPA’s DPB Stage 2 regulations.
The study sponsor historically had high levels of TTHM in its water that ranged between 105 and 171 µg/L. The municipality talked to TIGG about a water purification adsorption system. While some in the industry insist that coal-based activated carbon is the only effective means of removing disinfection byproducts from municipal drinking water, TIGG experts recommended their 5DC 12 x 30 virgin coconut activated carbon.
The municipality had an independent laboratory run a pilot study using a rapid small-scale column test. They used TIGG’s 5DC 12 x 30 NSF activated carbon, which is designed to remove low concentrations of contaminants from potable water. The laboratory found that initial TTHM concentrations of 138 µg/L were reduced to < 1.0 µg/L following treatment with virgin coconut activated carbon. Based on the scale-up of the testing, it was determined that a full scale carbon adsorber would effectively treat TTHMs for 325 days before the bed needed a changeout.
Not only is coconut-based activated carbon effective, it is typically more economical than coal-based activated carbon. The following report shows the laboratory’s results over a 24-day period.
Wright’s Well Control Services (WWCS) performed a hydrate remediation in the Gulf of Mexico at 7,200’ water depth from a proprietary skid containing a pump and motor. This self-contained subsea unit is powered from the surface through coiled tubing from a Multi-Service Vessel (MSV). Not limited by a Remotely Operated Vehicle’s (ROV) hydraulic energy, the subsea pump can increase volume up to 1 bpm, or reverse flow drawing pressure down to a sub-ambient -12 psi. For this project the integrated skid cleared 15 miles of 12” pipeline removing 9,000 barrels of hydrocarbons, condensate, gases and other fluids.
For a subsequent job, a paraffin and asphaltene blockage mixed with hydrates was successfully mitigated reopening four miles of pipeline. To date the skid has cleared a total of 30 miles of pipeline.
WWCS Gas Separator - Engineered to Prevent Hydrate Blockages within the Skid and its Coiled Tubing
A unique WWCS gas separator sits atop the skid and removes the gas mixed in the hydrate to the surface. This approach prevents the formation of additional hydrates in the coiled tubing outtakes used by both the gas separator and the pump for the remaining fluids. The old technique required returning the coiled tubing to the surface for thawing each time hydrates formed and reconnecting to the subsea pump–causing costly delays.
This system is further protected from hydrate blockages between the pipeline end termination/flowline end termination and the skid by injecting dispersant chemicals from a ROV panel as needed.
Engineered by WWCS to Ensure Safety
WWCS has engineered in a triple-redundant safety system to compensate for a loss of dynamic positioning (DP) or drive-off by the MSV from which the hydrate skid is deployed. An emergency quick disconnect (EQD) removes the skid’s coiled tubing connections via four hot stabs. Accumulators provide an isolated source of hydraulic power for the EQD which can be activated acoustically from the vessel, with ROV manipulators, or as a last resort with wire ropes. This safety system eliminates potential damage to the pipeline asset from the hydrate skid dragging across the seabed or thousands of feet of coiled tubing crashing down on the remediation site.
Engineered by WWCS to Protect the Environment
The skid has a number of environmentally friendly features. The pump is powered by filtered sea water avoiding any adverse impact from leaking or severing of the coiled tubing. The fluids the hydrate pump sends to the surface are contained in a specially designed tank on the deck of the MSV. Lastly, in the event of a MSV drive-off or loss of DP, emergency shut-off valves minimize the release of any hydrocarbons from the coiled tubing outtakes after an EQD. WWCS is currently developing a flush loop to eliminate any hydrocarbon release from an EQD deployment.
Shallow and Inland-Water Capabilities
The WWCS Hydrate Remediation System is also the solution of choice for shallow and inland-water pipelines. Depending on the
DAMMAM SECOND INDUSTRIAL CITY - IPS REHABILITATION WORKSIslam Nassef
Design capacities of the lift station
approximately 1670 m3/h. The
GWC’s initial goal for this project
is to develop a prioritized list of
repair/refurbishment projects based upon a comprehensive condition assessment and criticality analysis of IPS lift station planned to remain in operation.
Australasian Lab managers Conference: Gas Generation Dr Nicole Pendini 2019Nicole Renee Pendini
This presentation focus on on-site Gas Generation for the laboratory space supplying a range of analytical and specialty applications within the lab environment. I will focus on keeping green by preventing weekly cylinder and bulk supply deliveries, that waste energy offsite to generate the gas and petrol to delivery to the laboratory. The overall cost savings vs other methods (ROI < 1.5 years including service) and of course how Laboratory managers can significantly reduce their OHS/E risk with onsite Nitrogen, Hydrogen and Zero Air gas generators.
Enoc martinez el lazo y_el_abrazo-12187Costa_afuera
Enoc Martinez: Los lazos son tan sencillos y bonitos, que hasta pueden ser comparados con el amor, el cual une a las personas también con "lazos" y de todo tipo, lazos de amor, amistad, hermandad.. Nunca sueltes estos lazos!
This presentation covers frequent and costly incidents related to catalysts mal-operation with the focus of providing the plant operator with recommendations to avoid plant outages and catalyst losses.
New Technology for Cleaning both Open Loop and Closed Loop systems for large Chiller and Cooling Tower systems. This removed suspended solids and controls dissolved solids, to yield both water and energy savings to give an 18 month ROI.
2. Sequoyah Facts
• Unit 1 began commercial operation July 1, 1981
• Unit 2 began commercial operation June 1, 1982
• Unit 1 is licensed for operation through 2020 and Unit 2
is licensed through 2021
• Application process and inspections are ongoing with the
Nuclear Regulatory Commission (NRC) to renew the
licenses on both units; extending operation to 2040 and
2041
• Each unit can produce more than 1,160 MW of electricity
3. Days Leading up to the Event
• Fukushima/FLEX “fast track” mods in progress.
• 3/19/15, Operations tagged out the demineralized
(DI) water header to support piping modification
work.
• 3/19/15 - 3/24/15, Operations isolated/tagged out
nitrogen to Condensate Storage Tanks (CSTs) a few
times for Fukushima Mod, resulting in DO >100 ppb
until restored and treated (Carbo, Hydrazine).
• 1st Quarter Training: Technicians taught to walkdown
Secondary Plant panels and make adjustments IAW
procedure to ensure proper instrument operation.
4. Timeline 3/24/15
• 13:30 Operations releases clearance to restore the
DI water header.
• 15:30 Dayshift Chemistry technicians leave site, with
the 12-hour rotational Shift Tech to cover the
remainder of the day (3 hours). Duty Chemistry
Supervisor has stepped away from the site.
• 16:00 Operations hangs clearance to remove
nitrogen from the Turbine Building for Fukushima
Mod.
• 16:00 Operations reports that there is a DI water
header leak, location unknown.
5. Timeline 3/24/15
• 16:05 Chemistry Shift Technician notices a
significant rise in the Condensate DO concentration
for Unit 1 with corresponding drop in hydrazine. Due
to the DO and hydrazine-to-oxygen ratio exceeding
limits per 0-TI-CEM-000-001.1, Action Levels 2 and 3
were entered, requiring Unit shutdown if not restored
within 8 hours.
Cannot contact Duty Supervisor
Sr. Mgr, Chemistry notified, heading to the lab
9. Timeline 3/24/15
• 16:05 - 16:30 TB 685’ Lab walkdown performed:
Validated local inline instrument readings
Instrument panel (front) pressure/flow parameters appear normal
Grab sample by Waltron DO Meters confirms high DO
Raised hydrazine injection flow rate to Unit 1 to a maximum
• 16:30 Chemistry Management Team and Secondary
Chemist arrive. Additional technicians called in.
Duty Team directed to staff the OCC.
11. Timeline 3/24/15
• 16:45 Operations is requested to restore nitrogen to
the Turbine Building and locate/isolate (alleged)
demin water header leak.
• 17:00 A similar condition now starts on Unit 2, with
Action Level 2 and 3 limits being exceeded.
Overlay of Condensate DO spikes and CST makeup correlate
Same actions previously taken on Unit 1 now performed on Unit 2
Carbo/Hydrazine is added both the ‘A’ and ‘B’ CSTs
• 18:00 Unit 2 DO is restored to within AL1 limits.
• 18:45 Grab samples from CSTs are <50 ppb DO.
12. Timeline 3/24/15
• 19:00 Secondary Chemist recognizes that the
hotwell/condensate process flow is actually DI water.
Elevated sample line pressure at the sample panel.
DI pressure regulators were set to max pressure.
The regulators were adjusted from 40 psig back to the
normal setting of 19 psig.
• 19:05 Grab samples from Condensate Headers
(locally) are <20 ppb DO.
• 19:15 Normal DO values are restored to both Units
as inline instrument process flow is switched back
from DI water to Secondary Plant points.
16. Why did it Happen?
1. Off normal sample system configuration was not
fully understood or immediately recognized.
2. Weak status control and procedure guidance for
adjusting the DI water pressure regulators.
3. System design with DI water used as a backup.
4. Communication gap between Operations and
Chemistry for DI water restoration. Clearance did
not have Chemistry Lab restoration guidance.
5. Off normal DO procedure did not provide detailed
instructions (tribal knowledge not captured).
17. Lessons Learned
1. Maintain clear communications, turnover and
system monitoring when performing alignment
changes to ensure proper restoration to normal
conditions.
2. Capture tribal knowledge actions and OE into
procedures.
Unit 1 – July 1, 1981
Unit 2 – June 1, 1982
Board approved license renewal on August 18, 2011. In process to renew.
Purposes:
To help meet identified need for power between 2020 and 2021
Make good use of existing facilities and keeps a low-cost, zero carbon source of electricity available 24/7
Support TVA’s vision for cleaner, affordable energy
Ensure the safety of continued operation for employees and the community
Renewal requires extremely extensive and intense technical review of safety systems that must show all systems, structures and components in the plant can be safely managed and operated for that period
Requires extremely extensive environmental review
Requires public meetings and comments – already have had some on the environmental portion – these have been successful
This impacted the DI water supply to various loads, including the Chemistry sample panels. In order to maintain proper flow and pressure through the continuous hotwell/feedwater sample monitors for both Units, Chemistry adjusted the pressure regulators in the DI water supply lines to the sample panels.