Mercury/SO3/particulate horsepower rating system needed
Can you imagine selecting a race car without even knowing the horsepower of the engine? Instead you are given speeds of the twelve fastest cars, each operating on a different track, under different conditions. When it comes to Best Available Control Technology (BACT) for mercury, particulate, and SO3, that is a fitting analogy.
The controversy over the cost and performance of mercury removal systems on coal-fired boilers stems from the inability to distinguish between equipment performance and application variables. In comparing emissions among multiple units, it is not known how much is the result of actual differences in the efficiency of the mercury control technology and how much is due to different process variables.
The analogy is the same as comparing two different automobiles on different roads. One travels at a maximum speed of 70 mph and the other at 100 mph. But the rate of incline, the weight of the car, and other variables may have more effect on the speed than the horsepower of the motor. Even though you are comparing the power of multiple animals to an electric engine, horsepower has become an invaluable measurement device.
Particulate control decisions are becoming just as confused as mercury decisions due to the inclusion of condensibles in the measurement total. The acidification effects of SO3 on towns near utilities have made it necessary to find better ways to control this pollutant. Utilization of the “horsepower” concept to all three problems will go a long way to clarifying the routes and cost of control.
The equivalent to “horsepower” is a reference device. A miniature variable mercury removal device operated before bids are issued for the full scale system will tell the utility how efficient a device (how much horsepower) it will need to meet a selected percent removal (analogous to vehicle speed). Then the bidders will only need to bid to equal the performance of the miniature device. The ultimate proof of performance will be by running the miniature device in parallel to the full scale system and comparing results.
A variable efficiency miniature scrubber has been used for over 35 years to determine the relative particulate removal efficiency of different designs. This same device can be used to determine SO3 and mercury removal efficiency of spray towers, tray towers, venturi scrubbers, and sump scrubbers. There is already a miniature activated carbon system that also could be used for this purpose. There are proven miniature fabric filters and precipitators as well. So the horsepower rating tools are available, it is just a matter of utilizing them.
The McIlvaine Company, in its Power Plant Knowledge System, predicts that the introduction of the “mercury/particulate/SO3 horsepower rating system” will transform the industry. It will provide a new tool to regulators who can now obtain precision in the definition of BACT. Most importantly, it will free equipment vendors to focus on developing more efficient devices.
McIlvaine contends the supplier industry has been unfairly burdened with assuming the process risks. The assumption of these risks has been more important than supplying more efficient equipment. The result has been a lack of research and development effort on new devices. The adoption of the “system” would be a catalyst to accelerate the development of more efficient particulate, SO3, and mercury removal equipment.
Details of the miniature devices and more information on the concept are provided in the Power Plant Knowledge System which is described at: http://www.mcilvainecompany.com/energy.html#44I .
Bob McIlvaine
847-784-0012