Method for carbon sequestration and biological treatment of sulfur-containing waste alkali liquor

Method for carbon sequestration and biological treatment of sulfur-containing waste alkali liquor

  • CN 104,860,474 B
  • Filed: 05/09/2015
  • Issued: 01/22/2021
  • Est. Priority Date: 05/09/2015
  • Status: Active Grant
First Claim
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1. A method for carbon fixation and biological treatment of sulfur-containing waste alkali liquor comprises the unit processes of membrane pretreatment, chemical carbon fixation, primary aerobic oxidation, centrifugal dehydration, anaerobic reduction, secondary aerobic oxidation and membrane refinement, and is characterized in that:

  • (a) firstly, enabling sulfur-containing waste alkali liquor washed by NaOH solution from petrochemical and coal chemical devices to pass through a membrane pretreatment unit, and filtering suspended particles and solid impurities by a membrane pretreatment unit to obtain clean sulfur-containing waste alkali liquor;

    (b) the waste alkali liquor enters a carbonization tower for chemical absorption of CO2CO in exhaust gas2Diluting to reduce alkalinity of alkali liquor, enriching carbon source nutrient elements required by growth of desulfurization aerobic bacteria, and then enriching CO2The sulfur-containing waste alkali liquor flows into a first aeration tank;

    wherein carbon fixation is realized by chemical absorption of carbon dioxide in a gas-liquid countercurrent contact mode;

    (c) biologically oxidizing sulfide and sodium mercaptide into elemental sulfur, thiosulfate and sulfate in a first aeration tank through air aeration and catalytic oxidation of desulfurization aerobic bacteria, and controlling the ORP value of the solution to be maintained between-250 mV and-280 mV to form partially oxidized waste alkali liquid containing the elemental sulfur, the thiosulfate and the sulfate;

    (d) centrifugally separating and dehydrating, recovering elemental sulfur, and enabling filtrate to enter an anaerobic reduction bioreactor;

    (e) under the biological catalysis of sulfate reducing bacteria, the CO/H of the synthesis gas is obtained2As a carbon source and an energy source for the growth of sulfate reducing bacteria, thiosulfate and sulfate are anaerobically reduced to sulfide;

    regulating and controlling the reflux ratio, wherein the ratio of the waste alkali liquor flowing out of the anaerobic bioreactor and refluxing to the primary biological aeration tank is 0.3-0.8, and the ratio of the waste alkali liquor entering the secondary biological aeration tank is 0.2-0.7;

    (f) the partially oxidized waste alkali liquor is further oxidized to generate sulfate in a second aeration tank through air aeration and catalytic action of desulfurization bacteria, and the COD value is reduced, so that the concentration of sulfide is less than or equal to 0.1mg/L, and the COD is less than or equal to 100 mg/L;

    (g) filtering suspended impurities by a membrane refiner, refining to obtain dilute alkali liquor with the pH of 8-10, concentrating or adding a certain amount of NaOH solid, and then feeding the dilute alkali liquor into an acid gas washing tower for recycling.

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