Clean Coal Technologies in Electric Power Generation: A Brief Overview

摘要

There is great interest in the continued development and application of clean coal technologies because of the abundant and affordable coal supply and the ability of coal utilization technologies to comply with increasingly tight environmental controls. In addition to combustion process modifications and post-combustion cleanup, the improving efficiency of combustion and gasification cycles are leading to significant reductions in pollutant and CO_2 emissions. Currently available pulverized coal, circulating fluidized-bed, and IGCC plants have efficiencies of approximately eight percentage points, or a relative 25%, higher than the installed plant average, with correspondingly better environmental performance. The "near-zero emission" coal plant of the future will include CO_2 capture and compression for sequestration, a technology expected to come to fruition in the mid-2020s. In the near term, the choices for coal-based generating technology without CO_2 capture and storage include pulverized coal or circulating fluidized-bed combustion with supercritical steam cycles or pulverized coal combustion with ultra-supercritical steam cycles. The primary coal-based electricity generating technologies with CO_2 capture are IGCC with pre-combus-tion capture, pulverized coal with post-combustion capture, and oxy-fired pulverized coal or circulating fluidized-bed combustion.