Everyone in the CEMS business has been waiting to see how this goes and now we know. A federal court has struck down the EPA’s cap and trade regulation for Mercury.

The Associated Press: EPA’s Relaxed Emissions Rule Struck Down.

This means that the EPA will have to go back and revise their mercury regulations. It will be interesting to see how they handle this. For the time being I guess it is safest to assume that the time lines for installing and certifying you mercury equipment are unchanged.

We have recently completed upgrading two NOx/SOx CEMS systems at St Johns River Power Park in Jacksonville, FL. This project was started during the summer of 2006 when I started a series of meetings with the plant staff to review their existing systems piece by piece and ultimately developed a very detailed specification for the upgraded hardware and software. This was an important step in successfully completing the project.

The plant has environmental personnel who are responsible for the reporting and I&C staff who are responsible for maintaining the hardware. During the course of several meetings we discussed many design issues that they wanted to correct with the new design. We also specified in detail the equipment that we wanted to use and the standards that we wanted to follow. The time that we invested at this early stage has paid dividends in the final product. As with all new systems, we have had to track down some annoying bugs and work out a few unexpected issues but the upgrade went about as smoothly as can be expected.

Few things are as intimidating as ripping out a vital power plant system that has been running for about 13 years and committing to installing its replacement. We had a ten day outage for the installation of Unit 1. The goal was to use the lessons learned during the first installation to allow us to upgrade Unit 2 in 3 days. It was not easy but we were able to accomplish this goal.

The guys from Williams Industrial Services stand over the carcass of their recently defeated foe, the old CEMS cabinets. These things were built to last forever and did not give in easily.

Buzzards started to circle the stack about mid way through the outage. No one can remember that happening before. Despite the bad omen we pressed on and were ultimately successful.

A separate crew installed the new cabinets on the duct.

The new cabinets were staged outside the shelter so that they could be installed as soon as the old cabinets were removed.

The new cabinets were put in place.

We swapped the duct and stack analyzer racks after the factory acceptance test so that the new layout matched the old cabinet layout. This ended up requiring a great deal of re-wiring and re-tubing on site. For Unit 1 each cabinet was brought in separately and they were bolted together on site. This required the factory to disconnect all of the wiring between the cabinets. It took much longer than expected to reconnect everything. For Unit 2 we brought the air cleanup train, the duct analyzer cabinet, the stack analyzer cabinet, and the PLC cabinet into the shelter as a complete unit, rolling the cabinets along a few pieces of conduit. This proved to be a much better plan.

This picture shows the new Unit 1 cabinets on the right and the old Unit 2 cabinets on the left. 14 or so years of development makes a huge difference and the I&C techs love the new analyzers. They previously had pre-C series Thermo analyzers. I like to joke that the old analyzers actually had a little bird with a chemistry set who would then tweak a potentiometer to adjust the 4–20mA output like an old Fred Flintstone cartoon. The new i Series analyzers really pay off when you are prepping for linearities. The techs look so much more relaxed as they confidently flow the gas knowing that the analyzers will read as they should. They definitely don’t miss the drama of the old system.

One of our many design improvements was to mount the Teledyne Ultraflow 150 TIE components in a larger NEMA 4 box. This allows more room to work and the cables fold up neatly in the bottom. We don’t expect to have much trouble with the instrument but when they do it will definitely be easier to work on. Another tweak was to add a slow instrument air purge to the cabinet so that it always has clean dry air inside instead of stack gas.

The calibration gas cabinet to the new system has a couple of new tweaks. The CGA bottles have two solenoids in series to insure that a leak in a single solenoid will not cause them to fail a test.

One thing that we did miss in our spec and didn’t catch during the FAT was that the solenoid arrangement in the cabinet does not allow the solenoids to be easily removed. This was one of the few items in the new system that we were not completely happy with. I’m pretty sure that as soon as we wrap up the project the techs will be in here reworking this cabinet.

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We upgraded the calibration gas racks. The old system had the regulators mounted to the bottle with Teflon tubing going to the cal gas solenoids. We installed a bulkhead and mounted all of the regulators in fixed positions with SS tubing to the solenoids. A braided SS hose attaches the regulator to the bottle. This makes everything easier to read and the bottles easier to change out. One problem during installation is that we did not have an experienced tube bender available so it ended up looking like an Escher drawing of impossible angles. This still needs to be cleaned up and is a remaining punch list item.

One major improvement in the design of this system was to install accumulator tanks near the probes for blowback. The old system performed blowback through a 1/4” line with the solenoid actuated down in the shelter. The new system uses the accumulator tank mounted at the probe and 3/8” lines. The accumulator pressure is monitored and the solenoid is actuated small PLC’s mounted on the stack and duct. The blowback is much more forceful than the old system’s and the time to perform a blowback was cut to a third of the old time. This means that the blowbacks are more effective and disrupt the system for less time.

We call this the multiplexer box and we have one on the stack and one on the duct. The top left corner has a little AB Micrologix PLC which acts as a MODBUS slave to the PLC in the shelter. The PLC controls the blowbacks and multiplexes other measurements onto a single fiber cable going down to the shelter. The PLC also measures the temperature of the cabinet so that we know how hot the equipment gets during the day. The PLC will easily allow expansion of the system if we need to add anything to the duct or stack in the future and was relatively inexpensive. We also used a larger box to allow for expansion. The box is also purged with instrument air. The old system used a fixed multiplexer that allowed a couple of 4–20mA and a couple of digital signals to be passed. The two blue boxes on the top right corner control the probe and stinger heaters on the new M&C probe.

The new M&C probe on the stack and duct replaced EPM out of stack probes. The M&C has a superior design for the coarse filter that allows it to be easily changed. The coarse filter also has a much larger surface area than the M&C so we expect fewer problems. The probe sits at an angle because the welder who originally installed this flange 20 years ago did not pay attention to the bolt pattern when he attached it to the stack.

This picture shows the Teledyne UF 150 TIE enclosure on the left, the M&C probe in the middle, and the blowback accumulator box on the right.

It seems that as the original Part 75 CEMS systems start to reach the 12–13 year old mark it makes sense to replace them. Old PLC’s, analyzers, and other instruments are much harder to maintain than the newest generation of equipment. Spare parts are becoming harder to locate. Availability suffers and your technicians spend too much time baby sitting temperamental equipment. It ultimately becomes justifiable to replace everything. Many utilities are also realizing as they prepare for new Mercury CEMS that it is a good time to revisit their NOx/SOx CEMS as well. Your techs will have their hands full with these complex new system so upgrading the old systems to free up their time is a good strategy. It is important to do the preliminary legwork and specifiy a system that will fix any problems or design flaws in your old system and insure that your new system will perform reliably.

I met Troy Sonnier of Milivox while at the EUEC. His company digitally recorded all of the presentations given at the conference. His people had video cameras and laptops and were directly connected to the presentation computer so that they could directly record the PowerPoint presentation with the presenter audio. The camera captured the presenter and questions at the end of each session. It looks like a first class operation.

The recordings are available on DVD here http://www.millivox.net/public/EUEC.aspx. I purchased the package so that I can review some of the better presentations with my clients and view presentations that I could not attend. If you missed the conference, it might be well worth it to purchase the DVD’s of sessions that you wish you could have seen.

I’ll post a review of the package once I receive it in February.

I’m a little overwhelmed as I look through my 26 pages of notes that I have taken during this conference. I still have a lot to digest and a few new things to research.

Overall, here are my impressions regarding Mercury Measurement.

Time is wasting and the vendors are still working hard to improve their equipment. None of them have systems that would be considered “utility quality” in terms of reliability, repeatability, and serviceability. Many of the probe problems have been addressed and plugging is not a much of an issue as it was a year ago. Right now the problem seems to be in reliable calibration. They are addressing issues in obtaining a solid zero call and in drift between wet and dry measurement techniques on the span side. They are also exploring lower level measurements. There is more to learn here.

All of the vendors are still developing their oxidized mercury generators to test their converter efficiency as required. Richard McRanie of RMB says that if you are only calibrating on elemental mercury, you have no idea what you are measuring. You are effectively filling up your database with numbers but you don’t know if they mean anything.

Time is wasting and NIST and EPA still do not have traceability requirements established or protocols published for dealing with calibration against the standard. They are further along establishing requirements for the elemental generators. Most of the vendors use the same approach so developing a standard and testing criteria has been difficult but not as difficult as the oxidized generators. The vendors are using widely varying approaches for the oxidized generators so NIST is just now starting to develop evaluation criteria. These are non-trivial issues and will require time to develop. Meanwhile 1/1/2009 looms and we have no way to certify a system.

EPA reference methods other than Ontario Hydro are moving along. The instrument reference method (IRM) has been simplified and should be published soon but there is still a lot of contention with some of the elements. Richard McRanie of RMB has pointed out that testers are not moving on this due to the high cost and high uncertainty. Once an IRM is finalized they will not have much time to purchase equipment, test it, and train people. There are a lot of questions about the traversal requirements to measure stratification. You have to remember that the Hg concentration is prone to 10–50:1 excursions so you don’t know if you are measuring stratification or temporal changes in concentration. Jeff Ryan has cobbled together equipment and seems to be doing some excellent work on developing equipment specifically designed for the IRM that will be lighter and easier to use.

A sorbent based reference method is also on the way. Dennis Laudal who co-developed the Ontario Hydro is working on it. EPA is pushing the instrument reference method while many EPRI members are pushing the sorbent based method. I believe that a conceptual sorbent-based RM will be published in the next couple of months but the majority of the limited resources that the EPA has to expend on this will probably be spent on the IRM.

Vendors seem to be finding new problems at each of the early installation sites. There are still a lot of plant configurations, fuel sources, etc. that have not been tried and even among similar plants there are different problems. There is no way to predict what will happen when you install your CMMS, you will have to try and see.

Everyone is measuring x today and will need to be at 0.1x in the near future as they implement the required cuts in emissions. There is no telling if the system that you install today to measure x will work as well at 0.1x. This is uncharted territory. Thermo has started to test nitrogen as a dilution gas and has seen a 5x improvement in detectability. This seems to be an easy retrofit but we don’t know if there will end up being other ways to deal with this or if nitrogen will solve all of the problems. You may be in for major redesigns in the coming years.

Overall there are not many people out there with maintenance and troubleshooting experience with these systems. Also, experience gained at other sites will be valuable but there may be much to learn about your particular site. If you wait until the last minute to install, you may have trouble developing the expertise in house in time. This is a self serving statement on my part but it is important to remember that there is not going to be a trial period like part 75 CEMS where you have your certified system running but are not yet trading allowances. Mistakes and problems are going to cost $$$ from the start.

If you are waiting for all of this to wash out so that you can make a totally safe choice, it probably isn’t going to happen. If you are planning to go Appendix K then you should have a realistic plan of action and gauge the costs. A CMMS is going to cost between $275,000 – $480,00 for the instrument rack, calibrators, cleanup system, and umbilical. It will be expensive to maintain and there will be a lot of unknowns. There are risks associated with Appendix K. Make sure that you are realistic in your appraisal.

Measurement is going to be one vital piece of the pie but there are also a lot of other issues. You want to be able to make reliable and accurate measurements so that you can evaluate Mercury abatement strategies. There are tons of unknowns here and there are a lot of implications to different strategies. You have to realize that sorbents will end up in your ash and other waste products. You don’t want to make your ash unusable or create another waste problem. Recent court rulings also dictate that you can’t increase your particulate emissions in order to reduce your mercury emissions. In general you can’t increase the emission of one pollutant to reduce the emission of another.

To top all of this off, there are new studies that are undermining the assumptions that were used to justify the “slow” implementation of CAMR. There is going to be a big push by environmental and health groups to demand higher cuts in emissions on an even faster basis. The current legislation is way ahead of the technology now so I’m not sure how much faster it could happen but there will definitely be pressure and I would imagine new congressional bills will eventually be on the way. There is no telling how this will pan out. One thing for sure is that it is not going to be a boring choice of careers.

We are just starting the second day of the EUEC. Yesterday offered a gem or two during the Mercury sessions.

Dieter Kita of Thermo Fisher gave an update on their systems. For the most part he covered things that I already knew. There were a few new items. The first is that they are using a humidifier to add a little moisture to the calibration gas before it goes up the stack. He says that this is giving them more consistent calibrations.

The HgCl2 generator to test the converter efficiency has been coming along. He showed a few trends showing the performance improvement that they have achieved so far. The generator now stabilises in about 5 minutes. Earlier versions took closer to 30 minutes to stabilize. This improvement was vital for an operational CMMS.

He also elaborated on the chlorine source that they are using. When I initially heard about the generator they were speculating that they would use a solid chlorine source. Later they said that they were going to use a gas cylinder. There has been concern that this would cause safety and hazard concerns. Dieter said that they are going to use a small cylinder with a 250ppm Cl gas. This should alley some of the safety concerns 

Another concern that has been raised in many of the presentations is the trouble monitoring low levels of Hg (<-0.5 micrograms/m^3). Dieter talked about a new development for their low source systems. They are using nitrogen gas for dilution. This gives them a 5x improvement in detection limit and eliminates much of the noise in the system. After looking at the trends that he presented, I suspect that we may see nitrogen dilution systems become the norm as monitoring progresses. It will add a little cost and complexity to the system but as removal rates progress, the tradeoff will definitely be worth it. The key to good measurement in low level situations is to get a solid and repeatable zero. The nitrogen dilution seems to help in the situation.

Tom Robertson of EQM gave a little status report of Hg monitoring. He said that to the best of his knowledge only about 50 CMMS have been installed nationwide of the 1566 coal plants that will require monitoring. The utilities that he talked to who had installed systems indicated that the maintenance costs and demand of technician hours were far greater than they are used to with part 75 systems.

There is growing concern that equipment vendors will not be able to keep up with the manufacturing demand. There will also be a shortage of experienced technical personnel and test crews. His said that the from his conversations with the EPA, they are not buying the argument that there will not be enough stack testers to certify all of these systems. The bet that the EPA will allow a delay in implementation might not be a good one, especially with the political pressure to implement the reductions even faster than CAMR requires.

I asked about the strategy of using Appendix K monitoring while waiting for the bugs in CMMS to be hammered out. He indicated that the costs associated with this would likely be close to the costs of implementing a CMMS.

Stephen Niksa of Niksa Energy presented the progress of his company’s efforts to model and predict Hg emissions using their MercuRator software. He appears to be using very complex first principle models to predict Hg removal and emissions from coal samples. It might be worth your time to take a look just to have an idea of what is out there. If he is successful at prediction it could save a lot of money in extended testing.

Today I am looking forward to Bobby Chen of Western Kentucky’s presentation regarding concerns about the proposed instrument reference method. I caught his presentation at the Thermo Super Group meeting in Chicago a few months ago. I will post any new insights.

An item of humor. As I sat through the train of PowerPoint presentations, I was reminded of a site that I saw about 6 months ago. Lincoln’s Gettysburg presentation given in PowerPoint. Check it out, it is well worth it.