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CATALYST
Catalyst
Power Engineering Magazine Janurary 2013
Mercury Mitigation Strategy Through The Co-Benefit Of Mercury Oxidation With SCR Catalyst
An SCR Can Provide Mercury Removal Co-Benefits
With today’s emissions requirements you need a catalyst and catalyst supplier that can exceed your needs for NOx removal. Mitsubishi Hitachi Power Systems is the prime supplier of plate-type catalyst, and our plate technology has now operated successfully in over 750 units worldwide, with over 350 units supplied to coal fired units. Our catalyst is manufactured and designed by our affiliate company Babcock-Hitachi K.K. (BHK) in Akitsu, Japan, one of the original co-developers of Titanium Oxide based catalyst in the 1970’s. Our vast experience and knowledge makes us the most ideal solutions partner.
Our plate technology utilizes catalyst elements manufactured with active catalyst ingredients on a titanium dioxide matrix supported on a stainless steel mesh substrate. Multiple catalyst plate elements are then assembled in a steel unit case and these catalyst units are assembled into a welded steel frame to form a catalyst module for handling in the field. The catalyst modules are designed to be loaded through an access door located at the side of the SCR reactor.
Our plate catalyst is the optimum choice for your catalyst needs for Anthracite and Bituminous coals to Powder River Basin, Lignite, and Petroleum Coke. Hitachi’s success and innovation is everything you would expect from the original developer and supplier of DeNOx catalyst.
Advantages of plate type catalyst over other types of catalyst
- Higher Erosion Resistance to Fly Ash – The stainless steel substrate prevents erosion from occurring in high dust applications.
- Higher Resistance to Catalyst Pluggage - Plate catalyst has the distinct advantage of greater hydraulic diameter over other types of catalyst due to fewer corners and less low velocity zones. See Table 1-1 below. This feature also promotes easier and more effective cleaning.
- Higher Mechanical Strength – The center metal substrate acts as re-rod in reinforced concrete allowing for multiple installations and catalyst module removals without damage which is required for future regeneration of the catalyst.
- Easier Recycling - due to the large (relative to competitor design catalyst) metal content.
- Longer Service Life – due to new formulations
Catalyst Features
- High DeNOx efficiency
- Resistance to fly ash plugging
- Resistance to popcorn ash
- Erosion resistance
- Low SO2 oxidation formulas
- Half layer management capability
- Mercury oxidation catalyst
CM Plate Catalyst
- CM provides the longest life and the most Catalyst management flexibility
- CM Catalyst vs. Conventional or Regeneration
- Reduce the number of outages
- Lower overall cost
- Reduce volume
- Less uncertainty vs regeneration
- Full commercial guarantees
TRAC® – TRiple Action Catalyst
Mitsubishi Hitachi Power Systems offers the latest enhancement of NOx Reduction Catalyst for Selective Catalytic Reduction Systems which has been developed to increase the oxidation of elemental mercury.
This new catalyst called TRAC® (TRiple Action Catalyst) increases the oxidation of mercury with minimal chlorine levels. It can be used on Bituminous and Sub-Bituminous (PRB) fuels. Not only does this catalyst reduce NOx and oxidize mercury, it also minimizes the conversion of SO2 to SO3. Thereby the phrase, “Triple Action.”
Depending on the application, this catalyst can eliminate or minimize the need for other mercury oxidation agents such as halogens and activated carbon.
- Hg Oxidation -> MAXIMIZED
- SO2 to SO3 Oxidation -> MINIMIZED
- NOx Reduction -> MAXIMIZED
- TRAC® can be applied for both PRB and Eastern Bit coals
- Less than 0.25% of SO2/ SO3 oxidation rate per layer for Eastern Bit
- Sorbent injection for SO3 mitigation can be reduced
- 95% of Hg oxidation can be achieved at A/H outlet to avoid ACI for Eastern Bit coal and PRB with minimal or no Halogen Injection
- Catalyst volume can be reduced by TRAC®
