Chemical Absorption-biological Reduction Integrated Process On The Removal Of NO_x From Flue Gas

The combustion of fossil fuels generates NO_x pollutants which cause air pollution and acid rain. It is reported that the NO_x pollutants in our country is seriously. The development of the technologies for NO_x removal from flue gas is a problem we must to resolve. So it stares us. in the face to develop a new technology for NO_x removal with the characteristics of low cost, completely reduction of NO and high removal efficiency.The newly proposed and adopted method in our work for NO_x removal from flue gas, i.e. chemical absorption-biological reduction integrated process, is deemed as a promising method. As part of this work, in this paper, the character and reduction ability of strain FR-2 was studied, effect on the cell growth and the reduction ability of FR-2 by Fe(II)EDTA-NO and Fe(II)EDTA in the absorption solution was detected;the character and reduction ability of strain DN-2 was studied, effect on the cell growth and the reduction ability of DN-2 by Fe(III)EDTA in the absorption solution was detected;the basic study on the reaction process of the system was done. The aim of this work was to provide a new method and some fundamental data for NO_x removal from flue gas. The main experimental results were as follows:Strain Escherichia coli FR-2 can reduce Fe(III)EDTA which formed in the system efficiently, Fe(II)EDTA-NO and Fe(II)EDTA in the absorption solution would inhibit the cell growth of FR-2 and the reduction of Fe(III)EDTA. The model developed could well explain the inhibiton phenomenon.Strain Pseudomonas sp DN-2 can reduce Fe(II)EDTA-NO which formed in the system efficiently, and it could have the ability to reduce Fe(III)EDTA. In the period of the cell growth , Fe(II)EDTA-NO would first be biological catalyzed to Fe(III)EDTA, then as a electron accepter, Fe(III)EDTA would be biological reduce to Fe(II)EDTA. Fe(III)EDTA in the absorption solution would accelerate the cell growth of DN-2 but would inhibit the reduction of Fe(II)EDTA-NO. The method of chemical absorption-biological reduction integrated process was feasible to remove NO from flue gas. The dissolved oxygen increased with the concentration of O2, and the concentration of active Fe (II) EDTA would decrease, then the NO removal efficiency would decreased. The load of biological reduction would effected by the oxygen, and the key of this method to remove NO from flue gas was the load of biological reduction.