Experimental investigation of nitric oxide removal from flue gas using hexamminecobalt(II) solution scrubbing in a pilot-scale facility

Abstract

An experimental investigation of operational parameters, including liquid/gas ratio (L/G), inlet nitric oxide (NO) concentration, reaction temperature, and pH value of absorbing agent, on NO removal efficiency with hexamminecobalt(II) solution scrubbing was conducted on a pilot-scale facility to search optimal operation conditions. The experimental results show that NO removal efficiency increased with the pH value of hexamminecobalt solution, while the improving rate dropped gradually. When the reaction temperature increased, the NO removal efficiency increased first and then decreased. At the same time, NO removal efficiency increased with the increasing of L/G and hexamminecobalt concentration, while the removal efficiency did not change much at low NO concentration. The pH of 10.4 and L/G of 16 L/m were close to the optimal operation conditions, and the scrubbing temperature fell within a reasonable operation temperature. The experimental results can be used as a reference for the design and operation of scaled-up industrial devices.

Performance of Several Cobalt–Amine Denitration Solutions and Their Catalytic Regeneration by Graphene

“…Nitrogen oxides (NO x ) are one of the major pollutants that cause acid rain, ozone layer destruction, photochemical smog, and global warming. In the industrial waste gas of combustion boilers, NO is the main component of NO x . , Because of the growing importance of NO removal from exhaust gas, it would be desirable to find a suitable method as an alternative to the traditional selective catalytic reduction (SCR) process because catalyst costs, uncertain lifetime, and problems associated with ammonia slip are issues that SCR cannot avoid …”

“…Complexing the absorbed NO by a metal chelate solution is a promising method on account of its prompt absorption rate and high absorption capacity. For instance, there has been continuous denitration research on ferrous chelates Fe– ethylenediaminetetraacetic acid (EDTA) and Fe–n itrilotriacetic acid (NTA) in the past few decades. , The possibility of cobalt complexes [Co­(NH 3 ) 6 ] 2+ and [Co­(en) 3 ] 2+ for NO removal was also demonstrated subsequently by Tan’s team ,, and Long’s group. − …”

“…Moreover, cobalt is a precious metal and is harmful to the biosphere and the environment . Regeneration of the deactivated cobalt complexes from scrubbing liquids for reuse is necessary to reduce operating costs while meeting wastewater discharge standards. ,, Therefore, practical methods for the regeneration of cobalt complexes from spent liquids have been proposed.…”

“…In the industrial waste gas of combustion boilers, NO is the main component of NO x . 1,2 Because of the growing importance of NO removal from exhaust gas, it would be desirable to find a suitable method as an alternative to the traditional selective catalytic reduction (SCR) process because catalyst costs, uncertain lifetime, and problems associated with ammonia slip are issues that SCR cannot avoid. 2 Attempts have been made to remove NO x biologically directly from the flue gas stream using biofiltration.…”