Coal utilization in industrial boilers in China a prospect for mitigating CO2 Temissions

It is estimated from GEF statistical data for 1991 that more than 500,000 Aindustrial boilers (mostly stoker-fired) in China consume over 400 million tons Aof coal per year. Each year, because of low boiler efficiency, 75 million tons Aof coal is wasted and 130 million tons of excess CO2 are emitted. An analysis Aof 250 boiler thermal-balance test certificates and 6 field visits in three Aprovinces have shown that: (1) boilers with efficiencies of less than 70°/o Aaccount for 75% of the total boiler-population; (2) the main causes of the low Aefficiencies are high excess air and unburned carbon in the slag and fly ash. AThe effect of unburned carbon on CO2 emission is a balance of positive and Anegative contributions: while the unburned carbon does not produce CO2 Aemissions, its replacement carbon, burned at a low efficiency, contribusstes to a net increase in CO2 emissions. It seems from the analysis that the average Aboiler efficiency can be raised to 73% by relatively simple means, such as the Asize grading of the coal, improved boiler operating practice and some Ainexpensive equipment modifications. This could then result in savings each Ayear of 34 million tons of coal and a reduction in CO2 emissions of 63 million Atons at an estimated cost of $10 per ton of CO2. (c) 1999 Published by Aelsevierar Science Ltd. All rights reserved.