Resource-recyclable zero-discharge treatment technology and device for desulfurization wastewater in power plant

Abstract

The invention discloses a resource-recyclable zero-discharge treatment technology for desulfurization wastewater in a power plant. The resource-recyclable zero-discharge treatment technology sequentially comprises triple-box pretreatment, double-alkali scale removal, tubular UF ultrafiltration, nanofiltration, reverse osmosis and acid and alkali recycling. Deep zero-discharge treatment of the desulfurization wastewater in the power plant is achieved, and sodium chloride contained in the wastewater is fully utilized and directly prepared into available acid / alkali so as to achieve resource recycling.

Description

technical field [0001] The invention relates to the technical field of power plant desulfurization wastewater treatment, in particular to a zero-discharge treatment process and device for power plant desulfurization wastewater that can be recycled and utilized. Background technique [0002] The existing power plant desulfurization wastewater treatment processes include: [0003] Patent 1 (201710412099.X) discloses a low-consumption and zero-emission treatment method for electric field desulfurization wastewater, which removes divalent and trivalent scaling ions in desulfurization wastewater by pretreating the wastewater and adding sodium hydroxide, sodium carbonate, and sodium hypochlorite and inhibit the growth of microorganisms; then use tubular ultrafiltration membranes for solid-liquid separation; then use nanofiltration to concentrate desulfurization wastewater to further remove divalent and trivalent scaling ions in desulfurization wastewater; and then perform reverse ...

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Problems solved by technology

[0004] The defect of the patent 1 scheme is: no heavy metal scavenger is added in the pretreatment stage, and the heavy metal ions that cannot be precipitated and removed by hydroxide cannot be removed; sodium hypochlorite is added, and if the amount of addition is not properly controlled, it is easy to cause damage to the subsequent nanofiltration membrane and RO membrane; The sodium chloride solid obtained by evaporation is not of high purity and cannot be transported or sold, and it is rarely used in the field, so the value is not high; pretreatment requires additional acid and alkali, which consumes chemicals

[0012] The disadvantages of the patent 2 method are: the electrocoagulation electrode is easily passivated, the energy consumption is high, and the electrode consumption is fast, resulting in an increase in operating costs; the desalination rate and recovery rate of ED concentration are low; ED cleaning and maintenance are frequent and complicated; power plant desulfurization wastewater is passed through After nanofiltration, the monovalent salt content is still high, and ED consumes a lot of energy

[0029] The defects of patent 4 are as follows: if the flocculant and polymer are added during the pretreatment process, if the dosage is not well controlled, the subsequent ultrafiltration and nanofiltration systems will be polluted; since some chemicals are added before evaporation, it is easy to It leads to fouling of the evaporator heat exchanger, which affects the heat transfer efficiency of the evaporator; the evaporated mud cake needs to be reprocessed, which cannot realize resource utilization; pretreatment requires additional acid and alkali, which consumes chemicals

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