Upgrading and Retrofitting of SCR Denitrification Equipment System for Gas Turbine Generator Sets

     The upgrading and retrofitting of the SCR (Selective Catalytic Reduction) denitrification equipment system for gas turbine generator sets is a crucial measure to meet increasingly stringent environmental emission requirements and enhance equipment operational efficiency and reliability. The following sections elaborate on the necessity of the upgrade, key technical aspects, implementation steps, and expected outcomes:

     I. Necessity of the Upgrade

1. Environmental Regulatory Requirements: As national standards for nitrogen oxide (NOx) emission limits continue to tighten, gas turbine generator sets must meet lower emission standards (e.g., below 30mg/m3). Existing SCR systems may fail to comply due to issues such as catalyst aging and uneven flow distribution.
2. Equipment Performance Optimization: The upgrade addresses problems like high ammonia slip, catalyst clogging, and uneven flow distribution in the SCR system, improving denitrification efficiency and reducing operational costs.
3. Enhanced Technical Adaptability: Optimizing the SCR system design to accommodate the characteristics of low flue gas temperature and low dust content in gas turbines, ensuring efficient operation under varying conditions.

    II. Key Technical Aspects and Upgrade Directions

1. Catalyst Optimization
   • Poison-Resistant Catalysts: Add rare earth elements (e.g., cerium, lanthanum) or transition metal oxides (e.g., molybdenum, tungsten) to the catalyst formulation to enhance resistance to alkali metals, heavy metals, and other poisons, extending catalyst lifespan.
   • Novel Structured Catalysts: Use honeycomb or corrugated plate structured catalysts to increase specific surface area and reduce flow resistance, improving denitrification efficiency.
   • Multi-Layer Layout Design: Install backup layers to facilitate flexible catalyst replacement and maintenance, enhancing system adaptability.
2. Flow Field Optimization and Mixing Uniformity Enhancement
   • Guide Vanes and Flow Straighteners: Add guide vanes before the ammonia injection grid to optimize flue gas flow distribution, reduce velocity gradients, and improve the uniformity of ammonia and flue gas mixing.
   • Swirl Elimination Device Design: For swirling flue gas, install swirl elimination devices to convert rotational flow into straight-line motion, further promoting mixing and reducing impact on the catalyst layer.
   • Heat Exchange Tube Bundle Arrangement: Place heat exchange tube bundles between the swirl elimination device and the catalyst layer to recover waste heat, adjust flue gas temperature, and optimize flue gas flow characteristics.
3. Ammonia Injection System Optimization
   • Uniform Multi-Point Ammonia Injection: Use air-atomizing spray guns arranged in a ring pattern across the flue gas channel cross-section to achieve uniform multi-point injection of urea solution.
   • Dynamic Control of Ammonia Injection: Based on real-time flue gas composition monitoring data, employ adaptive control strategies to dynamically adjust ammonia injection rates, avoiding ammonia slip caused by excessive injection.
4. Intelligent Control System Upgrade
• High-Precision Monitoring Instruments: Install Fourier transform infrared spectrometers, laser-induced breakdown spectrometers, etc., to monitor real-time flue gas components such as nitrogen oxides, sulfur dioxide, and dust.
• Adaptive Control Algorithms: Utilize artificial intelligence algorithms like neural networks and fuzzy logic to dynamically optimize SCR system operating parameters, ensuring efficient and stable performance under complex conditions.