生物量混燒技術之障礙審視

Abstract

Utility-scale co-firing of biomass and coal to generate electricity is relatively undeveloped in North America, but many utilities are investigating biomass co-firing as an option, particularly for meeting renewable portfolio standards (RPS). Although economic factors will be the main factor influencing the growth of this technology, this report investigates two additional concerns: whether biomass will have a negative effect upon selective catalytic reduction (SCR) pollution control equipment and whether it will jeopardize current practices of selling fly ash as a cement substitute in concrete.

This report considers the results from research and operating experience in the U.S., as well as from a somewhat greater body of research in Europe to determine how the chemical and physical properties of biomass could affect these two issues. In particular, we focus on the potential effects of co-firing biomass in low proportions, typically less than 15%.

Table of Contents

• Table of Contents
• Energy Insights Opinion
• Executive Summary
• The Main Points
• Introduction
  • What's in biomass?
  • Figure: Coal and Biomass Ash Composition Differ
  • Table: Heat, Ash, and Chemical Composition of Selected Solid Fuels and Biomass Materials
• The Impacts on SCR Equipment
  • How SCR works
    • SCR in the U.S.
    • SCR deactivation mechanisms
    • Figure: Plugging, Masking, and Poisoning Mechanisms for SCR Catalyst Deactivation
    • Research on SCR deactivation
  • The problem with alkalis
    • Low biomass percentages
• Biomass Effects on Coal Fly Ash and Its Marketability
  • Coal fly ash use in concrete
  • Table: Coal Combustion Fly Ash Uses and Market Values in U.S. for 2003
    • Waste not, want more
  • How does biomass ash stand up under the standards?
  • Table: ASTM Specification C618 Chemical and Physical Specifications
    • Alkali-silica reactivity
    • Air entrainment and unburned carbon (LOI)
    • Permeability-sulfate resistance
    • Strength activity index
  • Changing the standard
    • Lack of ASTM standard for co-fired ash does not necessarily inhibit use
      • Florida Department of Transportation
    • The European standard
• Notes
• Acknowledgment
  • Synopsis