RDNOX Series Additive FCC additive
RDNOx series additives can be applied in reducing NOx emission from regeneration flue gases. As non-noble metal additives, RDNOx-I is appropriate for complete regeneration process with oxidizer. RDNOx-II is noble metal additives which are used as substitution of traditional oxidizer to promote CO combustion and reduce NOx emission. Each additive can be applied either alone or in combination, either in complete regeneration process or incomplete regeneration process.
Pt combustion improver can be replaced by the same or no more than 1.5 times amount of RDNOx-II noble metal additives, which can reduce 35-50% of NOx emission from flue gases. RDNOx-I, taking up 1-4% of the system capacity, can be used in combination to reduce 50-65% of NOx emission. Concretely speaking, for the complete regeneration units with NOX concentration no more than 500mg/m3, the application of RDNOx series additives can reduce NOX concentration in regeneration flue gases to less than 200mg/m3 in the condition that the catalyst consumption and products distribution in FCC units remain constant. Or for the ultrahigh emission units with NOX concentration more than 500mg/m3, a 60% decrease can be seen in NOX emission.
According to the chemical analysis of FCC regenerator nitrogen reaction, RDNOx series additives are classified into type I and type II by their functions. RDNOx-I is designed as NOx reduction additive, which takes non-noble metal as active sites and emphasize the catalytic activity of reduction reaction between CO and NOx so as to transfer NOx into N2 with the full use of CO from flue gases. RDNOx-II is a sort of NOx oxidizer aiming at reducing emission of both CO and NOx, which takes noble metal except Pt or non- noble metal with high combustion activity as substitution of active component Pt in conventional combustion improvers in order to promote CO combustion and reduce NOx products. These two sorts of additives can be used either respectively or in combination, and the better plan is taking RDNOx-II as the substitution of Pt oxidizer in order to reduce the NOx. On this basis, RDNOx-I is used to further promote NOx reduction and reduce NOx emission. Neither of the additives takes any destructive effect on the activity and selectivity of FCC main catalyst, or has negative impact on FCC products distribution.
The main specifications of RDNOx additives were shown in Table 1.
Table 1 Main Specifications of RDNOx
|Na2O, w %||≤0.25||≤0.20|
|M1Ox, w %||≥4||/|
|Pd, w %||/||0.040-0.055|
|Specific surface area, m2/g||≥180||≥220|
|Pore volume, ml/g||≥0.20||≥0.20|
|Apparent bulk density, g/ml||0.85~1.15||0.85-1.15|
|Attrition index (AI)||≤2.5||≤2.5|
Typical Application Data
RDNOx series additives are suitable for complete regeneration units with the NOx concentration in flue gases more than 100 ppm, especially up to 200-400 ppm when Pt combustion improver is used. RDNOx-II can also be applied in incomplete regeneration units.
RDNOx series additives can be applied widely since there is no special requirement on device types, operating conditions and raw oil properties. Furthermore, there is no negative impact on FCC products distribution and properties.
SINOPEC Beihai Petrochemical.