The ES-LEC process is a unique, low-cost/high-performance DeSOx system employing standard quarry size limestone to remove SO2 and SO3 from the flue gases of fossil fueled boilers and other industrial processes emitting sulfur compounds.
The system utilizes widely available, low-cost dry limestone granules in a simple moving bed that allows for design flexibility in a very small footprint.
Because of its design flexibility, the system is suitable for both new and retrofit applications.
BoldEco Environment possesses a great deal of experience in the design and supply of wet, dry and semi-dry scrubbing systems.
BoldEco Environment has been applying conventional wet, dry and semi-dry scrubbing technology for years now, and has recently acquired patented SO2 scrubbing technology for the following markets:
The EcoSorb LEC DeSOX process is a patented low-cost/high-performance limestone-based system capable of removing SO2 and other acid gases from the flue streams of fossil fueled boilers and other industrial processes emitting acid gases, including sulfur compounds at very high efficiencies (up to 99%). The system utilizes a simple moving bed of limestone granules that allows for greater flexibility in design in a very small footprint.
The EcoSorb TFB DeSOX process is a low-cost/high-performance hydrated lime-based system capable of removing SO2 and other acid gases from the flue streams of fossil fueled boilers and other industrial processes emitting acid gases, including sulfur compounds at very high efficiencies (up to 95%). The system utilizes a simple circulating fluid bed of hydrated lime dust and is close-coupled to a high-ratio fabric filter, allowing for an all-in-one solution that is flexible in design and covers a very small footprint.
The EcoSorb SDA DeSOX process is a low-cost/high-performance hydrated lime-based system capable of removing SO2 and other acid gases from the flue streams of fossil fueled boilers and other industrial processes emitting acid gases, including sulfur compounds at very high efficiencies (up to 90%). The system utilizes a simple once-through spray dryer where slurry injected through two-fluid spray lances comes into contact with the gas stream and neutralizes the acid gas component of the gas stream.
In the LEC process, hot flue gas is introduced into a semi-dry SO2 reactor, where it is forced into intimate contact with a bed of 1-8 mm diameter limestone granules covered with a film of water. As the gases pass through the bed, the SO2 is absorbed into the water film and reacts with the limestone to form primarily Calcium Sulfite and, to some degree, Calcium Sulfate on the surface of the granule. At the end of the process, the surface of the dried granules is regenerated to expose fresh limestone. The reactivated limestone granules are recycled back into the LEC reactor where they are mixed with a small amount of make-up limestone granules.
The granules that form the reaction bed are readily available from any quarrying facility worldwide and are typically 90% free calcium carbonate or better grade limestone. The reaction by-product is a dry waste stream that can be employed in a variety of uses.
The US Department of Energy (DOE), the Tennessee Valley Authority (TVA), and Babcock and Wilcox (B&W), all were impressed with the low cost and with the high efficiency of the LEC.
The LEC process and conventional limestone scrubbing have been compared on an equitable basis using flue gas conditions that would be expected at the outlet of the dust collector (typically an electrostatic precipitator, or ESP) on a 500 MW coal-fired boiler. The comparison was done by a government agency and compared it against various technologies, finding the LEC technology far less costly to operate than even the nearest competitor. The cost estimates were carried out in US dollars per ton of SO2 removed and based on burning 4% sulfur coal.
Easily adapted to existing installations
Small footprint makes it easy to find location in process
High efficiency even with low SO2 concentrations
Short installation and commissioning time requirements
Demonstrated SO2 removal efficiency between 90 and 99%
Few moving parts, simple to operate
Lowest energy consumption of all limestone scrubbing systems
Utilizes raw limestone, an inexpensive and safe material
Rocks in – rocks out process
Produces gypsum, a safe and valuable by-product
Utilizes 80% less water than conventional wet scrubbers
LEC technology is flexible in design and fit in a small footprint when compared to alternative technologies. This is accomplished by packing the maximum number of limestone beds and inlet and outlet gas paths in a given volume, while maintaining key design parameters (gas velocity, limestone wetness, bed speed, etc.).
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