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.