The Dry Scrubber Users Association (DSUA) is dedicated to exchanging valuable information among an industry specific group of power plant operators, and manufacturers and vendors that supply O&M parts and services for dry scrubber technologies. The annual forum for sharing industry information is the Dry Scrubber Users Conference, organized and presented each year by the DSUA.
There are varying technologies and competing manufacturers in dry scrubbing and the 2011 conference highlighted two fundamental technologies.
“Dry” scrubber technology
Dry scrubbers remove sulfur dioxide (SO2) and other acidic compounds from flue gas. The term “dry” refers to the flowable, dry product produced by the process. In the simplest terms, the process accommodates a chemical reaction with the flue gas that changes acid gas compounds to solid ones that are typically captured in fabric filters before the scrubbed flue gas leaves the stack. The scrubber reagent is primarily slaked lime (calcium hydroxide)
The Dry Scrubber Users Association is a non-profit, non-stock corporation formed in 2008. The mission is to facilitate the exchange of valuable knowledge among owners, operators and suppliers of dry scrubber technology used for flue gas treatment in the power generation industry. The DSUA annual conference will be held in Providence, R.I., running from Sept. 18-20, 2012. www.dryscrubberusers.org.
2011 conference highlights
Last year’s annual conference was held in Gainesville, Fla., with the highest attendance since the non-profit association was formed 4 years ago. The conference featured technical presentations, plant status updates, networking opportunities and vendor exhibits. In addition, technical breakout sessions were organized to discuss specific topics of interest such as reagent preparation and handling, corrosion and erosion, performance optimization and ash handling. OEM breakout sessions included semi-dry, CDS and other types of scrubbing technologies.
The 2011 conference provided the perfect venue to witness current CDS technology in application at the host plant, Deerhaven Generating Station of Gainesville Regional Utilities (GRU), in Gainesville, Fla.
Keynote speech and topical presentations
The 2011 conference theme was dedicated to compare and contrast CDS and SDA technology. The program included a comprehensive and informative plant tour of the Deerhaven Station, technical presentations, specific group discussions covering topics of industry interest and a couple of social events. The keynote speaker, from The Recovering Engineer, outlined methods to improve the decision making process when considering complex technical environments like flue gas desulfurization (FGD) and dry scrubbing applications.
The featured presentation, “BART: An FGD Retrospective,” discussed details of the Eastman Chemical Company group, which is determining the Best Available Retrofit Technology (BART) for retrofitting FGD on existing boilers. In summary, the advantages for CDS were:
- Simplicity – fewer rotating equipment components
- Up to 98 percent SO2 removal
- Utilize hydrated lime with no lime slurry handling
- Compact footprint
- Good turndown
- Market niche for small boilers and higher sulfur coals.
The advantages for SDA were:
- Can meet SO2 removal targets with reduced lime use
- Well established market for North America and Eastman Chemical experience
- Lower flue gas system pressure drop
- High controllability
At the time, Eastman Chemical decided to select SDA technology based on lowest life cycle cost, the company’s unique experience with operating SDA’s and the utilization of existing infrastructure and foundations.