NOx Emissions from Cement Mfg - US Environmental Protection ...

of NOx emissions in a cement kiln. The information obtained
during this study indicated that some plants indeed relied on
process monitoring and control as a means to maintain NOx
emissions within their respective permit limits. These plants
also indicated that no additional costs were involved in these
process control measures.5
Based on existing installations, the cost of a commercially
available kiln process control system is in the neighborhood of
$750,000.6 The resulting savings due to reduced energy and fuel
requirements and increased refractory life were estimated to be
about $1.37 per short ton of clinker. Thus, for a cement kiln
facility producing 300,000 tons/year of clinker the reduced cost
of producing cement is expected to recover process control
installation costs in less than 2 years.
6.2.1.2 Process Modifications. As discussed in Sections
5.1.2 and 5.3, process modifications measures can be highly site
specific and data from one site cannot be directly translated to
other sites. Data are not available to determine costs of
individual process modifications. Quite often a number of
process modifications and combustion control measures are
implemented simultaneously. Similar to combustion process
control approaches, process modifications have also shown to
reduce energy requirement and increase productivity, thus
providing an economic incentive to implement them in addition to
NOx reduction.
6.2.1.3 Low NOx Burners. Cement kiln burners, specifically
marketed as low NOx burners, require an indirect-fired kiln
system. Therefore, to install a low NOx burner in an existing
direct-fired kiln, it is necessary to convert the kiln-firing
system to an indirect-firing one. Two sets of costs are
therefore developed: (1) to install a low NOx burner in an
existing indirect-fired kiln, and (2) to install a low NOx burner
in an existing direct-fired kiln. In the first case, only the
costs of the low NOx burner equipment are considered, whereas in
the second case the costs of conversion of a direct-fired system
to an indirect-fired system are added to the low NOx burner cost.
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