Air 5 Mars

Page 1: Results of Gaseous Emissions Treatment

  • Operating Temperature: 850-1050°C

  • Consequences of Temperature Variations:

    • Too Low Temperature: Insufficient NH3 production

    • Too High Temperature: Oxidation of NH3 to NO

  • Influence of NH3/NO Ratio on Process Efficiency:

    • NH3/NO=1: Reduction rate of approximately 50%

    • NH3/NO=2: Reduction rate of approximately 90%

  • Application of SNCR Technology:

    • Commonly used in:

      • Cement plants

      • Municipal solid waste incinerators

      • Biomass and conventional fuel boilers

Page 1: Selective Catalytic Reduction (SCR)

  • NH3: Most widely used reducer

  • Promoted Reactions on Catalyst Surface:

    • Conversion of NO to N2

  • Reactions to Avoid:

    • Incomplete reduction of NO to N2O

    • Oxidation of NH3 to NO

  • Total Conversion Rates:

    • Reduction rates over 90% with proper catalysts

  • Types of Catalysts:

    • Supported Catalysts: Industrial use

    • Zeolite Catalysts (e.g., Cu/ZSM-5):

      • Disadvantage: Low thermal resistance in water presence

    • Noble Metals:

      • Disadvantage: Rapid oxidation of ammonia

Page 2: SNCR/SCR Hybrid Systems

  • Advantages of Hybrid Systems:

    • Balance between investment and operational costs

  • Ideal for Projects Where:

    • Significant reduction of NOx is needed

    • Space for catalyst installation is limited

    • Increased pressure drop is critical, incurring high operational and investment costs

  • Loss of Pressure:

    • Pressure drop due to catalyst installation requires overpressure to ensure gas exit, increasing costs

Page 2: Advanced Recombustion of NOx

  • Conclusions:

    • Each reduction technology has its own advantages and disadvantages

    • Emphasize complementarity between primary and secondary methods

  • Key Selection Criteria:

    • Compatibility with installation configuration and reduction method specifics

    • Amount of NOx to be treated

    • Investment and operational costs

    • Anticipation of regulatory and technological developments

Page 3: Air Pollution Treatment Introduction

  • Course Overview:

    • Instructor: Jean-François Lamonier, Université de Lille

  • Pollution Treatment Techniques:

    • Primary: Action at the source

    • Secondary: Action on the gaseous effluent

    • Destructive Processes: Make pollutants harmless

    • Recoverable Processes: Extract pollutants

Page 4: Destructive and Recoverable Processes

  • Destructive Processes Include:

    • Thermal oxidation or combustion

    • Catalytic oxidation or reduction

    • Chemical neutralization reactions

    • Biological treatments

    • Photocatalysis

    • Plasma methods

  • Recoverable Processes Include:

    • Absorption

    • Condensation

    • Adsorption

    • Membrane techniques

  • Innovative Processes (Research):

    • Coupling multiple techniques:

      • Adsorption - Catalysis

      • Plasma - Catalysis

      • Absorption - Catalysis

    • Objectives: Improve process efficiency from energy and environmental perspectives

Page 5: Choosing a Pollutant Treatment Technique

  • Recovery Processes: Limited number of pollutants

  • Recovery vs. Destruction Economics:

    • Higher investment cost for recovery processes, but viable if the recovered substance is valuable

    • Destructive processes apply for toxic pollutants

  • Key Considerations in Decision Making:

    1. Recovery or Destruction?

    2. Specifications Needed:

      • Flow rates and composition (fluctuations) are basic data

      • Temperature affects method choices and material selection

    • Define resulting efficiency based on regulatory constraints and valorization objectives

Page 6: Constraints in Pollutant Treatment

  • Considerations for Installation:

    • Space constraints (dimensions of installation)

    • Budget constraints (economic and technical feasibility)

Page 7: Volatile Organic Compounds (VOCs) Reduction Techniques

  • Definition of VOCs:

    • Any organic compound (excluding methane) with a vapor pressure of 0.01 kPa or more at 293.15 K or corresponding volatility under specific use conditions

    • Examples: Aromatics, ketones, alcohols, hydrocarbons, esters…

  • Special Case of Methane:

    • Inertness and classification differences from other VOCs

  • Main GHGs:

    • H2O, CO2, CH4, O3, N2O

Page 8: Sources and Reduction of VOCs

  • Sources of VOCs:

    • 90% natural, 10% anthropogenic

    • In industrialized regions (France): 80% anthropogenic

  • Reduction Progress:

    • Decrease in VOC emissions since 1992, significant dips observed between 2005 and 2009

    • France complies with EU directive for 43% VOC reduction by 2020

  • Sectors with Significant VOC Reduction (1990-2018):

    • Road Transport: -94% reduction

    • Residential/Tertiary: -63% reduction

    • Manufacturing Industry: -62% reduction

    • Energy Transformation: -86% reduction

    • Agriculture and Forestry: -74% reduction

Page 9: Impacts of VOCs and Reduction Strategy

  • Direct Effects of VOCs:

    • Inflammability risks

    • Toxic effects (cancer-causing, mutagenic, reprotoxic)

    • Malodorous

  • Indirect Effects:

    • Contribution to ozone layer depletion

    • Tropospheric pollution and health issues due to "bad ozone"

  • Stratospheric Ozone Formation:

    • VOCs decompose, forming radicals

  • Ozone Tropospheric Creation Potential (PCOP):

    • Higher concentration of O3 with increasing VOC levels

  • Reduction Strategies at the Source:

    • Primary technologies and secondary treatments for further VOC reduction.