1 Copyright © 2009 by ASME PROCEEDINGS OF NAWTEC17 17TH ANNUAL NORTH AMERICAN WASTE-TO-ENERGY CONFERENCE MAY 18-20, 2009, CHANTILLY, VIRGINIA, USA NAWTEC17-2372 NEW PROCESS FOR ACHIEVING VERY LOW NO X Mark White Covanta Energy Fairfield, NJ, USA Steve Goff Covanta Energy Fairfield, NJ, USA Steve Deduck Covanta Energy Fairfield, NJ, USA Oliver Gohlke Martin GmbH Munich, Germany ABSTRACT Over the last two and a half years, Covanta Energy, working with their technology partner, Martin GmbH of Germany, has developed and commercialized a new technology for reducing NO x emissions from Energy from Waste (EfW) facilities. NO x levels below 60 ppm (7% O2) have been reliably achieved, which is a reduction of 70% below the current EPA standard and typical levels of today’s EfW facilities in the United States. This technology represents a significant step forward in NO x control for the EfW industry. The technology, known as VLN™, employs a unique combustion system design, which in addition to the conventional primary and secondary air streams, also features a new internal stream of “VLN™-gas,” which is drawn from the combustor and re-injected into the furnace. The gas flow distribution between the primary and secondary air, as well as the VLN™-gas, is controlled to yield the optimal flue gas composition and furnace temperature profile to minimize NO x formation and optimize combustion. The VLN™ process is combined with conventional, aqueous ammonia SNCR technology to achieve the superior NO x performance. The SNCR control system is also integrated with the VLN™ combustion controls to maximize NO x reduction and minimize ammonia slip. A simplified version of the process, known as LN™, was also developed and demonstrated for retrofit applications. In the LN™ process, air is used instead of the internal VLN™ gas. The total air flow requirement is higher than in the VLN™ process, but unchanged compared to conventional systems, minimizing the impact on the existing boiler performance and making it ideal for retrofit applications. Covanta first demonstrated the new VLN™ and LN™ processes at their Bristol, Connecticut facility. One of Bristol’s 325 TPD units was retrofitted in April of 2006 to enable commercial scale testing of both the VLN™ and LN™ processes. Since installing and starting up the new system, Bristol has operated in both VLN™ and LN™ modes for extended periods, totaling more than one year of operation at NO x levels at or below 60 ppm (7% O2). The system is still in place today and being evaluated for permanent operation. Based on the success of the Bristol program, Covanta installed LN™ NO x control systems in a number of other existing units in 2007 and 2008 (total MSW capacity of over 5000 TPD), and is planning more installations in 2009. All of these retrofits utilize the Covanta LN™ system to minimize any impacts on existing boiler performance by maintaining existing excess air levels. Going forward, Covanta is making the LN™ technology available to its existing client base and is working with interested facilities to complete the necessary engineering and design modifications for retrofit of this innovative technology. For new grassroots facilities, Covanta is offering the VLN™ system with SNCR as its standard design for NO x control. An additional feature, particular to VLN™, is the reduced total combustion air requirement, which results in improved boiler efficiency. This translates into increased energy recovery per ton of waste processed. In addition to introducing the VLN™ and LN™ processes, this paper will provide an overview of the Bristol development and demonstration project. NO x and NH 3 slip data from Bristol will be presented, illustrating the extended operating experience that has been established on the system. Other operating advantages Proceedings of the 17th Annual North American Waste-to-Energy Conference NAWTEC17 May 18-20, 2009, Chantilly, Virginia, USA NAWTEC17-2372