Influence of HCl on CO and NO emissions in combustion

Abstract

a b s t r a c tThe influence of HCl on CO and NO emissions was experimentally investigated in an entrained flow reactor (EFR) and an internally circulating fluidized bed (ICFB). The results in EFR show the addition of HCl inhibits CO oxidation and NO formation at 1073 K and 1123 K. At the lower temperature (1073 K) the inhibition of HCl becomes more obvious. In ICFB, chlorine-containing plastic (PVC) was added to increase the concentration of HCl during the combustion of coal or coke. Results show that HCl is likely to enhance the reduction of NO and N 2 O. HCl greatly increases CO and CH 4 emission in the flue gas. A detailed mechanism of CO/NO/HCl/SO 2 system was used to model the effect of HCl in combustion. The results indicate that HCl not only promotes the recombination of radicals O, H, and OH, but also accelerates the chemical equilibration of radicals. The influence of HCl on the radicals mainly occurs at 800-1200 K.

Effect of HCl on NO Formation during CO/NH3 Combustion in an Entrained Flow Reactor at 1023–1223 K

“…A small amount of NH 3 may also inhibit the CO oxidation. Similar results at different temperatures are shown in a previous paper …”

Experimental study on CCl4/CH4/O2/N2 oxidation

“…The laminar flame speeds of CCl 4 /CH 4 /air mixture decreased with increasing Cl/H mole ratio of initial mixture, as shown in experiments and numerical simulation works [19]. The HCl formed in chlorinated flames also inhibited CO oxidation [20][21][22]. The previous studies indicate that the destruction products profiles are sensitive to reaction temperature, CH 4 /CCl 4 mole ratio and equivalence ratio.…”

Experimental investigation and numerical simulation of CO oxidation with HCl addition

“…Compared with coals, biomass has high content of chlorine, and significant amount of it is released as KCl(g), NaCl(g), or HCl(g), etc. [7][8][9][10][11][12][13]19], which promotes the recombination of free radicals OH, H, O, and HO 2 at high temperature and decreases their total amount, and results in an inhibition effect on CO oxidation [14][15][16][17][18][19][20][21][22][23][24][25][26].…”

“…The competition between A and B cycles determined whether the chlorine had an overall promoting or inhibiting effect on CO oxidation. Wei et al [22] investigated the influence of HCl on CO emission in combustion, the results indicated that HCl not only promoted the recombination of radicals O, H, and OH, but also accelerated the chemical equilibration of radicals. The influence of HCl on the radicals mainly occured at 800-1200 K. Wang and Chi [24] constructed a kinetic model of CO/H 2 /Cl 2 mixture oxidation, the results illustrated CO conversion varied inversely with Cl/H mole ratio and increased with temperature.…”