CN-122006453-A - Method for denitration of solid-phase liquid film by flue gas semi-dry method of low-temperature kiln

Abstract

The invention discloses a method for denitrating a solid-phase liquid film of low-temperature kiln flue gas by a semi-dry method, which adopts a solid-phase liquid film absorbent to absorb nitrogen oxide NO x in the low-temperature kiln flue gas, wherein the solid-phase liquid film absorbent comprises activated carbon particles AC and a liquid film adsorbed and loaded by the activated carbon particles AC, a solvent of the liquid film is water, the liquid film contains 0.5-2% of absorption auxiliary agent by mass percent and 3-7% of NaOH by mass percent, and the absorption auxiliary agent consists of sodium sulfite, disodium ethylenediamine tetraacetate EDTA-2Na and tetrabutylammonium bromide. In the absorption process of the absorbent, the liquid film not only serves as a solvent and a reactant, but also can change a reduction product from NO to NO 2 ‑ by changing a reaction path, so that the absorption efficiency is remarkably improved.

Inventors

• CAO SHANSHAN
• LI ZHEWEI
• WU JUNYE
• KE QUANLI

Assignees

• 浙江工业大学

Dates

Publication Date

20260512

Application Date

20260324

Claims (6)

1. 1. A method for denitrating a solid-phase liquid film of low-temperature kiln flue gas by a semi-dry method is characterized in that a solid-phase liquid film absorbent is adopted to absorb nitrogen oxide NO x in the low-temperature kiln flue gas, the solid-phase liquid film absorbent comprises activated carbon particles AC and a liquid film loaded by adsorption, a solvent of the liquid film is water, the liquid film contains 0.5-2% of absorption auxiliary agent by mass and 3-7% of NaOH by mass, and the absorption auxiliary agent consists of sodium sulfite, disodium ethylenediamine tetraacetate EDTA-2Na and tetrabutylammonium bromide.
2. 2. The method for denitration of the low-temperature kiln flue gas semi-dry solid-phase liquid film according to claim 1, wherein the liquid film contains 1% +/-0.2% of absorption auxiliary agent by mass and 5% +/-0.5% of NaOH by mass.
3. 3. The method for denitrating a solid phase liquid film by a low temperature kiln flue gas semi-dry method as claimed in claim 1, wherein the absorption auxiliary agent comprises, by mass, 0.3-0.7% of sodium sulfite, 0.08-0.15% of EDTA-2Na, and the balance tetrabutylammonium bromide.
4. 4. The method for denitration of a solid-phase liquid film by a low-temperature kiln flue gas semi-dry method as claimed in claim 1, wherein the specific surface area of the activated carbon particles is more than 1000 m 2 /g, and the carbon tetrachloride adsorption value CTC is more than 80%.
5. 5. The method for denitration of a solid-phase liquid film by a low-temperature kiln flue gas semi-dry method as claimed in claim 1, wherein the preparation method of the solid-phase liquid film absorbent comprises the following steps: s1, firstly, preprocessing activated carbon particles, grinding the activated carbon particles, and screening the particles with the particle size range of 2.5mm plus or minus 0.3mm to ensure uniform particle size; s2, dissolving an absorption auxiliary agent and NaOH in solvent water to prepare an impregnating solution, then impregnating the activated carbon particles pretreated in the step S1 in the prepared impregnating solution, impregnating for 10-60min at the temperature of 30-50 ℃, and taking out the impregnated solution after filling the impregnating solution into micropore channels in the activated carbon particle carrier to form an absorption liquid film; And S3, sucking away the redundant solution on the surface of the activated carbon particle carrier by using water absorption paper, thus obtaining the solid-phase liquid film absorbent.
6. 6. The method for denitration of a semi-dry solid phase liquid film of flue gas in a low temperature kiln according to claim 1, wherein the temperature of flue gas is 40-80 ℃ and the relative humidity is 0-100% RH when the solid phase liquid film absorbent absorbs nitrogen oxides NO x .

Description

Method for denitration of solid-phase liquid film by flue gas semi-dry method of low-temperature kiln Technical Field The invention relates to a method for denitrating a solid-phase liquid film by a low-temperature kiln flue gas semi-dry method. Background Today, stricter requirements are put on emission control of nitrogen oxides (NO x) in industrial kiln flue gas, and the emission amount of NO x is required to be controlled below 50mg/m 3. Although the traditional Selective Catalytic Reduction (SCR) denitration method is widely applied to ultralow denitration of the flue gas of the coal-fired power plant, for an industrial low-temperature kiln, the SCR denitration technology is difficult to effectively apply due to the characteristics of low flue gas emission temperature, high humidity, large NO x concentration fluctuation and the like, and the denitration requirement of the low-temperature kiln is difficult to meet. The low-temperature kiln has complex smoke characteristics, the NO x emission mainly takes NO as a main part, and the reduction difficulty of the NO is high. In addition, the flue gas temperature of the low temperature kiln is generally low, typically between 40-120 ℃, the humidity is close to saturation (100% RH), and the flue gas may also contain other components such as CO 2 with higher concentration, which characteristics make the traditional denitration technology face a plurality of challenges in the flue gas treatment of the low temperature kiln. At present, the denitration method of the low-temperature kiln is mainly divided into two major categories, namely a low-nitrogen combustion technology and a smoke tail emission reduction denitration technology. The low nitrogen combustion technology suppresses the generation of NO x by optimizing the combustion process, but its denitration efficiency is relatively low and it is difficult to meet the requirement of ultra-low emission. And the flue gas tail emission reduction denitration technology comprises dry denitration, wet denitration, semi-dry denitration and the like. The dry denitration technology, such as SCR, requires a higher reaction temperature and has poor adaptability to low-temperature flue gas, and the wet denitration technology has the problems of easiness in carrying out the absorbent by the flue gas, secondary pollution, large usage amount of the absorbent, low efficiency and the like. The semi-dry denitration technology combines the advantages of a dry method and a wet method, has higher denitration efficiency and better pollution control, but the traditional semi-dry denitration technology still has defects in screening and using modes of the absorbent, and needs further optimization and improvement. For example, chinese patent No. 115814573a discloses a comprehensive treatment system for producing mineral source nitro humic acid and nitro fulvic acid, which includes a treatment of nitrogen oxides, and a compound treatment of nitrogen oxides through physical adsorption of silica gel, molecular sieve, activated carbon and the like and chemical absorption of sodium hydroxide or sodium peroxide solution, absorption liquid made of slaked lime and calcium carbonate and the like. The process is complex, the absorption cost is high, and the absorption efficiency of each treatment is low. Therefore, it is important to develop a denitration technology which is suitable for low-temperature kiln flue gas and is efficient, stable, economical and easy to industrialize. Based on the background, the invention provides a novel semi-dry solid-phase liquid film denitration technology, aims to solve the defects of the prior art in low-temperature kiln flue gas denitration, adopts a solid-phase carbon material with higher absorption efficiency to load strong base, does not need conditions such as high temperature, catalyst and the like, and provides an effective solution for ultralow emission of an industrial low-temperature kiln. Disclosure of Invention Aiming at the technical problems in the prior art, the invention aims to provide a method for denitration of a semi-dry solid-phase liquid film of low-temperature kiln flue gas. The design thought of the absorbent of the invention combines the good physical adsorption performance of the porous solid material with the advantage of improving the absorption efficiency of the liquid phase absorbent, and the liquid absorbent is loaded on the porous solid material, thus greatly reducing the volume of the absorbent. After adsorbing NO 2 to the pore canal, the porous solid material reacts with the nano liquid film which takes NaOH loaded by the pore canal of part of the porous solid material as a main absorption component and is added with an absorption auxiliary agent, and the porous solid material and the nano liquid film loaded by the pore canal of the porous solid material simultaneously improve the absorption efficiency of NO 2. The technical scheme adopted by the invention is as follows: A met