(84g) Advances in the Use of a Bio-Physicochemical Model to Characterize, Optimize the Chemical Absorption-Biological Reduction Integrated System for NO Removal

Zhao, J., Institute of Industrial Ecology and Environment
Li, W., Zhejiang University

One promising technology for NOx
removal from flue gas is the chemical absorption-biological reduction (CABR)
integrated process, in which NO is absorbed by aqueous solution of Fe(II)EDTA
and the absorption product, Fe(II)EDTA-NO, is reduced biologically. At the same
time, Fe(II)EDTA, oxidized by O2 in flue gas, could be regenerated
in a function of iron-reducing bacteria.

A kinetic model based on mass transfer coupled
with chemical reaction and bioreduction was developed to simulate and predict
the NOx removal by the CABR system in a bio-trickling filter. The
developed model was validated by the experimental results (the average relative
deviation kept within 5.72%) under different operating conditions, e.g. NO/O2
concentration, gas/liquid flow rate, and subsequently was used to predict the
system performance. NO distribution at different inlet concentrations in the
gas phase along the bio-trickling filter was also modeled and predicted.

Furthermore, the liquid flow rate and
total iron concentration were optimized for >90% NO removal efficiency,
which were 38.8 L h-1 and 10 mM under the typical operating
condition (2 L min-1 gas stream
containing 3% (v/v) oxygen and 500 ppm NO) respectively. Sensitivity
analysis found
that the performance of the
CABR process was controlled by the bioreduction activity of Fe(III)EDTA, and
the least activity has been achieved. This work could help us with the scale-up
design and operation of the CABR process in the industrial application.