Flue gas step-by-step desulfurization and denitrification method

A desulfurization and denitrification, flue gas technology, applied in the field of desulfurization and denitrification, can solve the problems of high investment and operation costs, large water consumption, increased consumption of absorbent, etc., achieve low investment and operation costs, avoid blockage and wear, and denitrification rate Improved effect

Pending Publication Date: 2021-09-07
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The limestone-gypsum method is currently the most widely used and most mature desulfurization process in the world, but this process also has some shortcomings, such as high initial investment and operating costs, large water consumption, large consumption of absorbent raw materials, and easy scaling of equipment , clogging, rotten candles and wear, will produce CO 2 Greenhouse gas, which has adverse effects on the atmospheric environment; the double-alkali method has high desulfurization efficiency, and the absorbent will not produce sediment in the absorption tower, avoiding blockage and wear, and has high operational reliability. The disadvantage is the side reaction of sulfuric acid after oxidation of sodium sulfite Sodium is difficult to regenerate, and fresh absorption liquid needs to be continuously replenished. The process is relatively complicated, and the reaction conditions are relatively harsh. It requires high experience and technology of operating personnel and automatic and precise control. The advantages of the magnesium oxide method are mature technology, reliable operation, and high desulfurization efficiency. , the by-products (such as magnesium sulfite, magnesium sulfate, etc.) can be sold or recycled as commodities after processing. The disadvantage is that the application of this process is limited by the source of MgO. However, it is difficult because the method started late in my country and lacks practical operation experience; the advantages of the ammonia method are fast reaction speed and high desulfurization efficiency. The disadvantage is that the cost of absorbent is high, the production process of solid ammonium sulfate is complicated, and the ammonia tank installed separately is also a major source of danger, which is prone to problems such as ammonia escape and corrosion in the system, resulting in increased consumption of absorbent
However, this process has disadvantages such as low denitrification efficiency and difficulty in reusing the absorbed product.

Method used

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  • Flue gas step-by-step desulfurization and denitrification method
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  • Flue gas step-by-step desulfurization and denitrification method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Embodiment 1: desulfurization experiment

[0041] Prepare Na with a concentration of 0.2mol / L 3 PO 4 Solution 300mL, with 20% volume fraction of H 3 PO 4 The solution adjusts its pH to 7.02, consuming H 3 PO 4 Solution 24mL, at this time the total phosphoric acid concentration in the sodium phosphate buffer solution C P =0.41mol / L, the temperature of the absorbing liquid is 40°C, and SO is introduced into it 2 Simulated flue gas, SO 2 The concentration is 2000ppm, the flow rate is 0.5L / min, the pH value of the solution is measured with a precision pH meter every 2 hours, and the gas source is turned off when the pH value of the solution drops to about 5.0. After aeration for 20 hours, the pH of the absorption solution dropped to 5.18. At this time, a total of 600L of simulated flue gas was injected, SO 2 A total of 3429.8 mg, using iodometric method to measure SO not absorbed by sodium phosphate buffer solution 2 51.4mg, sodium phosphate buffer solution to SO ...

Embodiment 2

[0043] Embodiment 2: denitrification test

[0044] Synergistic Absorption of NO by Sodium Phosphate Buffer Solution Containing Sulfur-rich Solution 2 The influencing factors are Na 3 PO 4 Concentration, SO 3 2- Concentration, pH, in order to determine the multifactorial effect on NO 2 The influence of absorption rate, carry out the design and analysis of orthogonal experiment, in the experiment, for the convenience of experiment, use sodium phosphate buffer solution and Na 2 SO 3 Configured as an absorbent.

[0045] The experimental implementation steps are as follows:

[0046] 1) Configure absorbent

[0047] Prepare a certain concentration of absorbent according to the experimental requirements, and use laboratory distilled water as the solvent for the preparation. Calculate the required drug quality according to the concentration of the solution, weigh the drug quality with an electronic balance, and add it to distilled water. With 20% volume fraction of H 3 PO 4...

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Abstract

The invention provides a step-by-step desulfurization and denitrification method, firstly, the sodium phosphate buffer solution is used for desulfurization, the desulfurization rate can reach 98.5%, due to the fact that no sediment exists, blockage and abrasion are avoided, the product is used for next-step denitrification after pH is adjusted, and resource utilization of the product is achieved. The sulfur-containing pregnant solution obtained by utilizing the desulfurization product is used for denitration, the denitration rate can reach 96% or above, the denitration rate is greatly improved compared with a simultaneous desulfurization and denitration method, the desulfurization product is utilized, the investment and operation cost is low, and more cost is saved.

Description

technical field [0001] The invention belongs to the technical field of desulfurization and denitrification, and in particular relates to a step-by-step desulfurization and denitrification method for flue gas. Background technique [0002] As a large developing country with coal as the main energy source, China's total coal consumption has been kept at a relatively high level, and SO in the flue gas of coal-fired power plants 2 and NO X It is the prerequisite for the formation of acid rain and ozone depletion, which threatens human health and ecological environment quality; therefore, the development of economical, safe and efficient desulfurization and denitrification technology has important practical significance and broad application prospects. [0003] At present, the relatively mature desulfurization and denitrification technology is a combination of wet desulfurization and dry denitrification technology. [0004] Wet desulfurization technologies include limestone-gyp...

Claims

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Application Information

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IPC IPC(8): B01D53/78B01D53/50B01D53/56
CPCB01D53/78B01D53/507B01D53/56B01D2258/0283B01D2251/304B01D2251/61
Inventor刘乃瑞张鑫李雪纯杨雅婷张步超侯璞明
OwnerNORTHWESTERN POLYTECHNICAL UNIV