Technics of flue gas desulfurizing through catalytic oxidation method and by-product polymerizing iron sulfate through catalytic method

Abstract

The invention discloses a process using catalyzing and oxidizing method on fume desulfurization and using catalyzing method on producing polyferric sulfate, a solvent containing ferric ion is used as the desulfurization absorption liquid, a sulfur dioxide in fume is absorbed and dissolved through the absorption liquid to convert into a sulfurous acid which can be oxidized into sulfuric acid by utilizing air base on the catalyzing and oxidizing effect of the ferric ion; when the concentration of the sulfuric acid in the desulfurization absorption liquid is between 3 percent and 10 percent, the desulfurization absorption liquid is introduced to the polymeric ferric sulfate synthesization system, simultaneously, ferrous sulfate and catalyzer are added, an oxidizing, hydrolyzing and polymerizing reaction occurs between ferrous sulfate, catalyzer and sulfuric acid of desulfurization absorption liquid, a desulfurization side product, polyferric sulfate is produced; so the invention can recycle the sulfur resource and get the high value-added desulfurization side product, the transportation fee is lower, the benefit from the desulfurization process is outstanding.

Description

technical field [0001] The invention belongs to the technical field of flue gas purification, and relates to a process for desulfurizing flue gas by a catalytic oxidation method and by-producting polyferric sulfate by the catalytic method. Background technique [0002] Flue gas desulfurization by liquid-phase catalytic oxidation of transition metal ions such as iron and manganese can produce dilute sulfuric acid as the main by-product. The dilute sulfuric acid desulfurization process developed by Chiyoda Corporation in Japan uses dilute sulfuric acid containing iron ions as the absorbing liquid. With the participation of iron ions, the catalytic oxidation and absorption of sulfur dioxide is realized through the redox cycle of iron ions. The sulfuric acid produced by this process is used to produce gypsum, which solves the problem of blockage and scaling in the lime desulfurization process. However, the by-product The added value is low. [0003] In order to increase the add...

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Problems solved by technology

[0004] Chinese patent (Patent No. 00101556.7) uses iron filings as a desulfurizer. During the desulfurization process, ferrous sulfate crystals are first obtained, and then the ferrous sulfate crystals are oxidized into solid polyferric sulfate in a high-temperature oxidation tower. This ferrous oxidation process is used Similar to the one-step method of preparing solid polyferric sulfate, no need to add other oxidants, but there may be the problem of incomplete oxidation of ferrous ions

Although the direct oxidation method has simple process and production equipment, and is easy to operate, it has the problems of high price and large amount of oxidant, so it is difficult to popularize and apply in industrial production

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