148
Water for Energy and Fuel Production
The reduction in the volume of flue gas lowered the heat losses and increased the
boiler efficiency. The air-preheating temperature was reduced by 192°F by enriching combustion air by 22.8% volume of oxygen. The boiler performance was significantly improved even with a small addition of oxygen (2%–3%) in air. With the
use of staged air admissions, the NO x emission was also reduced by one-third. This
was, however, accompanied by some decrease in combustion efficiency. The use
of oxygen-enriched air in the primary combustion stage increased flame stability,
reduced carbon burnout, and moderately reduced the overall NO x emissions. The
carbon conversion (96%–98%) and the boiler efficiencies (81%–83%) remained high
in their entire study.
The issues of CWF atomization and its effect on the optimization of combustion
efficiencies in boilers, diesel engines, and gas turbines are continued to be investigated. Coal–water slurry has, however, proven to be an important synthetic fuel. It
has a significant economic potential [137] and its application to generate heat and
power will continue to grow [138–140].
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