Study On Cumulative Effect Of Organic Metabolites In The Flue Gas Desulfurization Process Of Simulated Sulfur-containing Flue Gas

In the process of non-ferrous metal smelting,coal burning and steel production,a large amount of industrial furnace flue gas rich in SO₂ is produced,which causes serious pollution to the atmospheric environment.Due to heavy metals,dust and salt,etc.,traditional calcium desulfurization by-product desulfurization gypsum lacks resource utilization value,and stacks up a large amount of land;ammonia desulfurization increases operating costs due to the high price of liquid ammonia,and there is ammonia escape phenomenon,and induce haze.In view of the shortcomings of traditional technology,the research group proposed a closed-cycle flue gas biochemical desulfurization and sulfur recovery process in the early stage.However,in the long-term operation,the volatile fatty acids and soluble microbial products produced by the metabolism of sulfate-reducing bacteria gradually accumulate.It interferes with the oxidation and neutralization reaction of sulfur,and reduces the purity and yield of sulfur by increasing sulfur particle size,adsorption,net entrapment and flocculation,which severely limits the engineering application of this process.Therefore,this thesis studies the component evolution and cumulative effects of volatile fatty acids and soluble microbial products in the biochemical desulfurization system,and analyzes their effects on sulfur turbidity,environmental conditions,sulfite and sulfur physical and chemical properties during the redox neutralization reaction.The study is carried out to clarify the mechanism of action of metabolites and sulfur,providing theoretical guidance for improving sulfur yield,and technical support for the engineering application of this process.The research results are as follows:?1?SRB flue gas biochemical desulfurization process produces two volatile fats,acetic acid and propionic acid in two scale reactors.The expansion of the reactor scale changes the residual metabolic components from acetic acid to propionic acid,both of which restrict the production of S^2-and hinder the progress of the sulfur production reaction.Propionic acid changes the law of SO₃^2-concentration in the process of sulfur formation?from first decline and then gentle to first decline and then rise?.The two VFAs did not change the molecular structure of sulfur S₈,and the characteristic peak at 430 cm^-1 was shifted by the modification of volatile fatty acids.?2?The protein concentration of SRB flue gas during the biochemical desulfurization process increases first and then decreases.It is the main accumulated soluble microbial product,accounting for 60%to 100%of the total soluble microbial product.Both bovine serum albumin?hydrophobic protein?and casein?hydrophilic protein?reduce sulfur turbidity,and bovine serum albumin has a greater impact on turbidity by increasing the sulfur particle size.They reduce the p H and increase the ORP in the sulfur production process;the sulfur molecular structure obtained under the action of the two proteins is still S₈,and the characteristic peak at 220?229cm^-1 is shifted by protein modification.?3?The concentration of polysaccharides in the biochemical desulfurization process of SRB flue gas increases first and then decreases,accounting for 10%-20%of the total SMP.Glucose,sucrose and starch reduce sulfur turbidity through flocculation,and at the same time reduce the ORP of sulfur production process,of which starch has the greatest impact.Sucrose changed the concentration of SO₃^2-from a rapid decrease and then a slow decrease to an increase and then decrease;the concentration of SO₃^2-in the experimental group with accumulated starch first decreased and then increased.The molecular structure of sulfur obtained under the action of polysaccharide is still S₈,and the characteristic peaks at 151?158 cm^-1,433?439 cm^-1 and470?471 cm^-1 are shifted by polysaccharide modification.