To SCR or SNCR?
While in some cases the choice between SCR and SNCR technology for NOx reduction appears straightforward, there is a middle way that enables the use of the less expensive option of SNCR technology. Lechler explains how cement producers can benefit from its high-efficiency SNCR technology. By Dipl Ing Claus Fritze, Lechler, Germany.
Figure 1: structure of the APC Process
Proven technologies for the reduction of NOx emissions, in addition to primary measurements, are either the selective catalytic reduction (SCR) or the selective non-catalytic reduction (SNCR) process.
The choice between SCR and SNCR technology depends on the ammonia emission limit values and the NH3 in the raw material feed (the baseline). Wherever the baseline is high and the ammonia limit value is low, SCR technology is the best choice for NOx abatement as the SNCR technology can only add ammonia to the process.
However, the investment costs for SNCR technology are substantially lower. Moreover, Lechler and its system partner STEAG show that with a so-called High Efficiency SNCR the ammonia slip (added ammonia by the SNCR) can be kept at a very low level so that the legal requirements can be achieved even without a catalytic technology.
