Integrated Dry Nojso, Emissions Control System: Advanced Retractable Injection Lance Sncr Test Report

The DOE sponsored integrated Dry NOJSO, Emissions Control System program (a Clean Coal Technology ill demonstration) is being conducted by Public Service Company of Colorado. The test site is Arapahoe Generating Station Unit 4, a 100 MWe down-fired utility boiler burning a low-sulfur western coal. The project goal is to demonstrate up to 70 percent reductions in NO, and SO, emission through the integration of: (1) down-fired low-NO, burners with overfire air; (2) Selective NonCatalytic Reduction (SNCR) for additional NO, removal; and (3) dry sorbent injection and duct humidification for SO, removal. The installation of the burners and overfire air system resulted in a decrease in furnace exit gas temperature of approximately 200°F. The temperature decrease reduced the effectiveness of the SNCR system at low loads. This report documents the third phase of SNCR tests (corresponding to the seventh test phase of the overall program), where an additional injection location was installed to increase the low-load NO, removal performance. The new injectors consist of a pair of retractable in-furnace lances which were designed to provide a high degree of load following flexibility through on-line adjustments of the injection angle. The majority of the test program was conducted using retractable lances proved by NOELL (ARIL lances). Subsequently, an alternative lance design provided by Diamond Power Specialty Company was evaluated. Before installation of the lances, the existing wail-injection location was capable of providing only 11 percent NO, removal at 60 MWe (at an NH, slip limit of 10 ppm). With the new lances, NO, removals in excess of 35 percent are achievable at the same load