Fig. 3. Clean coal technology is key to the future of coal-fired power generations.
When entering the carbon dioxide capture system, the flue gas is first routed to the flue gas cooler for conditioning, such as cooling and dehydration, and additional sulphur dioxide removal. Te flue gas is cooled because the absorption of carbon dioxide is favoured at lower temperatures. Te cooled flue gas will contact a circulating sodium hydroxide solution for polishing sulphur dioxide removal, where 98% of the remaining sulphur dioxide is removed from the stream because it interferes with the amine’s ability to react with carbon dioxide.
Te conditioned flue gas will be routed to the absorber, where carbon dioxide
is captured by the amine-based solvent through a chemical reaction. Te carbon dioxide rich solvent stream is sent to the regenerator, or stripper, where the carbon dioxide is released from the solvent using low pressure steam. Heat from the steam breaks the weak bond between the carbon dioxide and the solvent, liberating the carbon dioxide and leaving the solvent behind for additional carbon dioxide capture use. To complete this production process, the captured carbon dioxide will be compressed, dried and then transported via pipeline to the West Ranch oil field, which is located near Vanderbilt, in Jackson County, Texas. l
US utility plans further coal to gas conversion I
ndianapolis Power & Light Company (IPL) is shortly to file plans with the Indiana Utility Regulatory Commission (IURC) to repower unit seven at Harding
Street generation station (HSS) from coal-fired to natural gas. This conversion is part of IPL’s overall wastewater compliance plan for its power plants. “IPL has a commitment to provide affordable electricity,
and converting Harding Street unit seven to natural gas is the best plan for our customers because it is the reasonable, least cost option,” said Kelly Huntington, IPL president and ceo. “Compliance with current and future EPA standards will continue to increase the cost of electricity for our customers.” In May, IPL received approval from the IURC to convert Harding Street units five and six from coal to natural gas.
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IPL plans to stop burning coal at the Harding Street power plant in 2016, if plans to convert unit seven are approved. This plan would reduce IPL’s dependence on coal from 79% in 2007 to 44% in 2017, making natural gas IPL’s largest fuel generation source. IPL also remains a leader in wind and solar generation. A recent study by Environment California Research & Policy Centre indicated that Indianapolis ranks fifth in the USA for solar per capita. As a result of converting unit seven to natural gas,
the Harding Street coal pile and ash ponds will be closed. Compliance with EPA standards will continue to significantly increase the cost of electricity for customers. This compliance plan at Harding Street will cost the typical IPL residential customer approximately a dollar a month, if the proposed plans are approved by the IURC. l
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