CN1274392C - Damp dry type flue gas purifying method and device - Google Patents

Abstract

The present invention relates to a semi-dry fume purifying method and a device thereof. An antalkali is uniformly mixed with water in a mixer, and the adding weight of the water is 2% to 15% of the weight of dry matters; fume is added to the humidified antalkali before atomizing spray, the stay time of the antalkali mixing and reacting with the fume is 0.5 second or more after the fume is added to the humidified antalkali, and then the atomizing spray is started; for a fume emission source with the original temperature from 50 DEGC to 1000 DEGC, a critical temperature T1 is determined, and T1 is higher than 110 DEG C and lower than 150 DEG C. When the temperature of the fume is lower than T1, the atomizing spray is stopped. The atomizing spray is started when the temperature of the fume is higher than T1, and the temperature after the atomizing spray is controlled in the temperature level of T1. The device comprises an atomizing spray reactor connected with a flue in series, and a dust remover, wherein the flue is connected with the mixer before the flue is connected with the atomizing spray reactor. The method and the device thereof are used for preventing corrosion and scale formation, and are particularly suitable for an industrial kiln with large temperature variation ranges.

Description

Damp dry type flue gas purifying method and device thereof

(1) technical field

The invention belongs to flue gas purifying technique and device thereof.

(2) background technology

Atomizing sprays into a kind of method that milk of lime is normal use in the damp dry type flue gas purifying in flue gas.For keeping the good mobility of milk of lime, the concentration of emulsion can not be too high in the actual engineering.When raw flue gas was low, heat contained in the flue gas was also lower, can cause that flue-gas temperature is low excessively after spraying into milk of lime in this case, to such an extent as to can't keep the temperature of system enough to be higher than the dew point of system, thus the corrosion and the fouling of system caused.

Another kind method is to add a certain amount of water in antalkali, sprays into flue gas (as NID system of ABB AB) and can reach the effect that reduces raw flue gas temperature increase flue gas relative temperature after mixing.But very limited for preventing to be bonded in the water yield that adds in the antalkali, so when the raw flue gas variations in temperature, the control of the water yield and antalkali dosage is all too complicated.Particularly increase when too high when the raw flue gas temperature in the actual motion, add water contained in the agent in the alkalescence and evaporate rapidly, and because the water yield does not reach the effect that increases the flue gas relative temperature for a short time.

(3) summary of the invention

The present invention proposes a kind of damp dry type flue gas purifying method and device thereof, has solved limitation and the low problem of purification efficiency that traditional half dry type flue gas treating process can't satisfy raw flue gas temperature wide variation; Also solved the problem that traditional half dry type flue gas treating process easily causes system's corrosion and fouling.

Technical scheme of the present invention: this damp dry type flue gas purifying method is characterised in that:

Antalkali is evenly mixed with water in a blender, and the addition of water is the 2%-15% of dry matter weight;

Antalkali behind the humidification added flue gas before atomizing spray; After antalkali behind the humidification added flue gas, the time of staying 〉=0.5 of mixing, reacting with flue gas second began atomizing spray again;

To the fume emission source of original temperature from 50 ℃ to 1000 ℃, determine " critical-temperature " T1, and 110 ℃＜T1＜150 ℃; When the raw flue gas temperature was lower than T1, atomizing spray quit work; When the raw flue gas temperature surpasses T1, start atomizing spray, and the temperature behind the atomizing spray is controlled at the temperature levels of T1.

Above-mentioned deduster has exhaust opening and ash hole, it is characterized in that: flue connects before the atomizing spray reactor, connects blender earlier, and this blender has that water adds inlet and antalkali adds inlet.

The ash hole of above-mentioned deduster is communicated with blender by pipeline.

The ash hole of above-mentioned deduster was both communicated with blender by pipeline, communicated with the deduster inlet again.

The shell of above-mentioned atomizing spray reactor is reaction tower or flue itself.

Above-mentioned deduster is sack cleaner or electrostatic precipitator.

The control basic principle of this process system is as follows: to a definite fume emission source, through detailed calculated, consider the raw flue gas amount, raw flue gas range of temperature and raw flue gas water capacity excursion are determined " critical-temperature " T1, and 110 ℃＜T1＜150 ℃.When the raw flue gas temperature was lower than T1, atomizing spray quit work.Contained water effective promotes the reaction of sour gas at particle surface behind the antalkali humidification, and the maintenance system temperature enough is higher than the dew-point temperature under the corresponding water content.Start atomizing spray when the raw flue gas temperature surpasses T1 and the temperature behind the atomizing spray is controlled at the temperature levels of T1.

Make flue gas its humidity under certain humidity be higher than dew point in the purification of flue gases by semidry process system, thereby system keep dry state.Except the characteristic of antalkali, the humidity of flue gas, temperature have material impact to the efficient of removing sour gas.Usually the relative humidity increase helps the removal of sour gas.

Beneficial effect: the present invention carries out corresponding startup, stops atomizing spray by critical-temperature is set, simple to operate, flexible, simple in structure, compact, method by antalkali humidification and atomizing spray, make the antalkali after humidification is handled before atomizing spray, add flue gas system, effectively utilized the time of staying of flue gas in the atomizing spray reactor, increased absorption, absorb and neutralization reaction efficient, improve purification efficiency and operational reliability, given full play to the reaction efficiency of antalkali under different temperatures.The invention solves traditional half dry type flue gas treating process and can't satisfy the limitation of raw flue gas temperature wide variation, anti-locking system corrosion and fouling, be particularly useful for the bigger Industrial Stoves of range of temperature, applied widely, SR is low, can reach the desulfuration efficiency more than 90% under calcium sulfur ratio 1.1-1.3.

(4) description of drawings

Accompanying drawing is a structural representation of the present invention.

1-flue, 2-atomizing spray reactor, 3-deduster, 4-water, 5-blender, the fresh antalkali of 6-, 7-compressed air atomized water, 8-deduster ash discharge efflux, 9-deduster ash discharge returns the humidification reactor, 10--deduster ash discharge returns flue, 11-purifies the back flue gas.

(5) specific embodiment

Embodiment as shown in drawings, this damp dry type flue gas purifying process is used for removing the acid gas component of burnt gas, its process:

Antalkali evenly mixes with water in a blender, and the addition of water is the 2%-15% (weight ratio) of dry, thereby increases the water capacity of antalkali, promotes absorption, absorbs and neutralization reaction.

Antalkali behind the humidification added flue gas before atomizing spray, effectively to utilize the time of staying of flue gas at atomization process, promote reaction.

Sharp agent mixes, reacts with flue gas in flue (or blender of special configuration) after adding flue gas in the alkalescence behind the humidification.The time of staying 〉=0.5 of flue gas second between the adding point of nertralizer and the adding point of atomized water.

When the raw flue gas temperature is lower than " critical-temperature " T1 (110 ℃＜T1＜150 ℃), atomizing spray quits work, but because system temperature is lower in the case, water evaporates speed contained in the antalkali is slower, still can effectively promote reaction, reach clearance the sour gas height.

The damp dry type flue gas purifying process system, the atomizing spray control method makes system can satisfy the raw flue gas temperature from 50 ℃ to 1000 ℃ scope, guarantees the drying regime of system simultaneously.

The damp dry type flue gas purifying process system, the requirement of the time of staying of the adding point of atomized water is put in the adding of nertralizer, it is characterized in that being introduced in advance the antalkali hybrid reaction of humidification, atomizing spray then, thereby antalkali effectively utilizes the time of staying of atomizing spray reactor to react, thereby realized system compact, simple, effectively utilized the effect of system's time of staying.

Technology of the present invention and system are made up of following major part: fresh antalkali 6 and water 4 humidification by mixing of gas.Can add part in the blender 5 and answer product with sending out from the remaining nertralizer of deduster 3 collections.Amount of water is controlled at the 2%-15% (weight ratio) into dry.After the humidification processing, antalkali joins in the flue gas and with flue gas and mixes, and sour gas adsorbs, absorbs, neutralization reaction in antalkali particle after humidification is handled and the flue gas.Spray into compressed air atomizing water 7 to reduce flue-gas temperature to flue gas in follow-up atomizing spray reactor 2, increase flue gas relative humidity, antalkali and sour gas further react simultaneously.Atomizing spray reactor 2 can be the special reaction tower that makes up, also flue itself.Product and remaining nertralizer are collected in deduster 3.The deduster ash discharge effluxes 8 and can form the deduster ash discharge and return the part of flue 10 and/or return the part that the deduster ash discharge returns humidification reactor 9, and deduster can be sack cleaner formula electrostatic precipitator.

Claims (1)

1, a kind of damp dry type flue gas purifying method, its method is characterised in that:

Antalkali is evenly mixed with water in a blender, and the addition of water is the 2%-15% of dry matter weight;

Antalkali behind the humidification added flue gas before atomizing spray; After antalkali behind the humidification added flue gas, the time of staying 〉=0.5 of mixing, reacting with flue gas second began atomizing spray again;

To the fume emission source of original temperature from 50 ℃ to 1000 ℃, determine " critical-temperature " T1, and 110 ℃＜T1＜150 ℃; When the raw flue gas temperature was lower than T1, atomizing spray quit work; When the raw flue gas temperature surpasses T1, start atomizing spray, and the temperature behind the atomizing spray is controlled at the temperature levels of T1.