Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Boiler modifications cut mercury emissions 70 percent or more, research team finds

05.10.2005


Inexpensive technique verified in full-scale tests at three coal-fired power plants



Researchers at Lehigh University’s Energy Research Center (ERC) have developed and successfully tested a cost-effective technique for reducing mercury emissions from coal-fired power plants.

In full-scale tests at three power plants, says lead investigator Carlos E. Romero, the Lehigh system reduced flue-gas emissions of mercury by as much as 70 percent or more with modest impact on plant performance and fuel cost.


The reductions were achieved, says Romero, by modifying the physical conditions of power-plant boilers, including flue gas temperature, the size of the coal particles that are burned, the size and unburned carbon level of the fly ash, and the fly ash residence time. These modifications promote the in-flight capture of mercury, Romero said.

The ERC researchers reported their findings in an article titled "Modification of boiler operating conditions for mercury emissions reductions in coal-fired utility boilers," which will be published in a forthcoming issue of the journal Fuel.

Mercury enters the atmosphere as a gas and can remain airborne several years before it precipitates with rain and falls into bodies of water, where it is ingested by fish. Because mercury is a neurotoxin, people who consume large quantities of fish can develop brain and nervous ailments. Forty-four states have mercury advisories.

Coal-fired power plants are the largest single-known source of mercury emissions in the U.S. Estimates of total mercury emissions from coal-fired plants range from 40 to 52 tons.

The U.S. Environmental Protection Agency last March issued its first-ever regulations restricting the emission of mercury from coal-fired power plants. The order mandates reductions of 23 percent by 2010 and 69 percent by 2018. Four states - Massachusetts, New Jersey, Connecticut and Wisconsin - issued their own restrictions before the March 15 action by the EPA.

The changes in boiler operating conditions, said Romero, prevent mercury from being emitted at the stack and promote its oxidation in the flue gas and adsorption into the fly ash instead. Oxidized mercury is easily captured by scrubbers, filters and other boiler pollution-control equipment.

The ERC team used computer software to model boiler operating conditions and alterations and then collaborated with Western Kentucky University on the field tests. Analysis of stack emissions showed that the new technology achieved a 50- to 75-percent reduction of total mercury in the flue gas with minimal to modest impact on unit thermal performance and fuel cost. This was achieved at units burning bituminous coals.

Only about one-third of mercury is captured by coal-burning power plant boilers that are not equipped with special mercury-control devices, Romero said.

Romero estimated that the new ERC technology could save a 250-megawatt power unit as much as $2 million a year in mercury-control costs. The savings could be achieved, he said, by applying the ERC method solely or in combination with a more expensive technology called activated carbon injection, which would be used by coal-fired power plants to reduce mercury emissions. The resulting hybrid method, says Romero, would greatly reduce the approximately 250 pounds per hour of activated carbon that a 250-MW boiler needs to inject to curb mercury emissions.

The new ERC technology was developed by Romero, ERC director Edward Levy, ERC associate director Nenad Sarunac, ERC research scientist Harun Bilirgen, and Ying Li, who recently received an M.S. in mechanical engineering from Lehigh.

The breakthrough follows years of work by ERC researchers in optimizing boiler operations to control emissions of NOx, CO, particulates and other pollutants.

For their mercury-emission research, the ERC group received a total of $1.2 million in funding from a consortium of utility companies, the Pennsylvania Infrastructure Technology Alliance and the U.S. Department of Energy.

It is expensive to check for levels of mercury emissions, says Romero, because mercury levels are measured in parts per billion, while NOx levels are measured in parts per million.

The ERC tests were performed at a power plant in Alexandria, Virginia, and at two units of a power plant in Massachusetts. The ERC and Western Kentucky University will conduct tests next year at an additional unit firing Powder River Basin sub-bituminous coals.

Romero discussed his group’s findings at the 2004 Pittsburgh Coal Conference in Osaka, Japan, where he gave a paper titled "Impact of Boiler Operating Conditions on Mercury Emission in Coal-Fired Utility Boilers."

He has given half a dozen presentations on his group’s findings so far this year, including an address at the ICAC (Institute of Clean Air Companies) Clean Air Technologies and Strategies Conference in Baltimore in March.

Kurt Pfitzer | EurekAlert!
Further information:
http://www.lehigh.edu

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Solar Collectors from Ultra-High Performance Concrete Combine Energy Efficiency and Aesthetics

16.01.2017 | Trade Fair News

3D scans for the automotive industry

16.01.2017 | Automotive Engineering

Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs

16.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>