Evaluation of gas reburning and low NO{sub x} burners on a wall-fired boiler

An evaluation of Gas Reburning (GR) and Low NO{sub x} Burners (LNB) has been completed at Public Service Company of Colorado`s Cherokee Station Unit 3. The goal of the demonstration was to reduce NO{sub x} emissions by 70%. The reduction was to be achieved from the pre-project level prior to LNB retrofit. The GR system was supplied by Energy and Environmental Research Corporation (EER) and the LNBs were supplied by the Foster Wheeler Energy Corporation. The project was carried out in three phases in which EER designed the GR system and obtained necessary permits (Phase 1), constructed the system and completed start-up tasks (Phase 2), and evaluated its performance with both Optimization Tests and a Long-Term Demonstration (Phase 3). As directed by the Cooperative Agreement, environmental monitoring was conducted in each phase. Measurements were taken by plant personnel and an EER Field Testing Team and were divided into two types. ``Compliance Monitoring`` was conducted by plant personnel to satisfy requirements of regulatory agencies, while ``Supplemental Monitoring`` was conducted by EER personnel to develop a database of environmental impacts of the technology and to ensure environmental acceptability of the project. This document presents environmental monitoring data obtained during the Optimization Testing period, November 11, 1992 to April 23, 1993. Compliance Monitoring was conducted primarily in two areas, air emissions and aqueous discharges. The unit is required to meet an SO{sub 2} limit of 1.2 lb/MBtu and an opacity limit of 20 percent (6 minute average). Therefore, the plant monitors flue gas SO{sub 2} and opacity continuously and submits Excess Emissions Reports to the Colorado Air Pollution Control Division on a quarterly basis. Discharge limits for the aqueous effluent from the plant and monitoring requirements are specified by a permit issued by the Colorado Water Quality Control Division