CN104474881B

CN104474881B - A kind of caprolactam that utilizes burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning

Info

Publication number: CN104474881B
Application number: CN201410716115.0A
Authority: CN
Inventors: 李东林; 汪然; 刘应峰; 陈洪会; 曹静
Original assignee: CHENGDU HUAXITANG INVESTMENT Co Ltd
Current assignee: CHENGDU HUAXITANG INVESTMENT Co Ltd
Priority date: 2014-12-02
Filing date: 2014-12-02
Publication date: 2016-06-08
Anticipated expiration: 2034-12-02
Also published as: CN104474881A

Abstract

The invention discloses a kind of caprolactam that utilizes and burn the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, the method is the smoke mixture of utilizing salkali waste and flue gas to mix, the Na obtaining after circulation cleaning₂SO₄Solution is prepared the process of sodium acid carbonate product, described salkali waste is that caprolactam burns salkali waste, and described flue gas is coal-fired flue-gas, coking tail gas or sintering tail gas, and it is drying solid that described caprolactam burns salkali waste, by weight percentage, comprise following component: Na₂CO₃：65～85%；Na₂SO₄: 15～30%; NaCl:2～5%. Realize and utilized salkali waste to administer waste gas, the object of the treatment of wastes with processes of wastes against one another, in addition, the method also can obtain and be worth higher sodium acid carbonate product, so not only save the energy, reduce and pollute, but also reduced the cost of gas cleaning and avoided the secondary pollution of gas cleaning, solved thoroughly the pollution of salkali waste to environment, social benefit is very remarkable.

Description

A kind of caprolactam that utilizes burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning

Technical field

The present invention is that a kind of caprolactam that utilizes burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, is specifically related to caprolactam and burns the technology of preparing of salkali waste for gas cleaning sodium acid carbonate, belongs to the field of purification of flue gas.

Background technology

The continuous progress of the industry such as oil and chemical industry is in promoting economic development, also caused pollution to environment, at present, global pollution problem is on the rise, more cause the discharge of common concern and attention, especially coal-fired power plant, coal-burning boiler and the flue gas of refuse burning of countries in the world etc., quite serious to the pollution of atmosphere, we know, contain a large amount of flue dust, carbon dioxide, SO in coal-fired flue-gas₂And NO_XEtc. harmful substance, wherein, the carbon dioxide of fuel discharged in burning is the main matter that causes greenhouse effects; SO₂、NO_XAnd fly ash granule is again the main source of atmosphere pollution; Certainly, the flue dust that the flue gases such as coal-burning boiler produce is also the one of the main reasons that causes atmosphere pollution, and its main component is also SO₂And NO_X. It is reported, China approximately has 70% city suspended particulates level to exceed standard, the SO in 2/3 peri-urban atmosphere₂Exceed standard, therefore, for improving the air quality of current environment, the improvement of these pollutants is very urgent especially with reduction of discharging.

In China, flue gas desulfurization and denitrification is topmost measure in air contaminant treatment, flue gas desulfurization technique is a lot of both at home and abroad, comprise limestone-gypsum method, ammonia process, two alkaline process, rotary spraying technique etc., in various desulphurization denitration technology, the most widely used is exactly adsorbent, generally include sodium class adsorbent, magnesium class adsorbent, calcium class adsorbent etc., in smoke gas treatment process, conventionally the flue gas stream that makes to contain SOx and NOx compound contacts with absorbent particles and removes all SOx and a large amount of NOx compounds that are present in flue gas stream, practical effect is good, certainly, for residual SOx and the NOx compound of better removal, also can continue the flue gas after purifying to contact with adsorbent solution phase, thereby any residual SOx in removal flue gas stream and NOx compound. existing situation is, the desulfurizing and denitrifying process of flue gas is one and must matches with industrial production process and the sustainable maximization industry processing of carrying out, though be dry method washing adopt solid absorbent or the adsorbent solution that adopts of wet scrubbing, for whole fume desulfuring and denitrifying technique, its use amount is very huge.

The method of existing patent documentation CN101570370(high resource treatment of cyclohexanone waste saponification lye, 2009-11-04) and mono-kind of CN102874848A(from cyclohexanone spent lye, reclaim the method for sodium acid carbonate and organic acid sodium salt, 2013-01-16) a kind of production method of utilizing spent lye preparing sodium bicarbonate is all disclosed, particularly patent documentation CN101570370, disclose the method for utilizing the carbon dioxide reaction in cyclohexanone spent lye and flue gas and obtain sodium acid carbonate, reach the technological effect for the treatment of of wastes with processes of wastes against one another zero-emission, but be proven, the quality that is obtained sodium acid carbonate by the method also rests on the crude product stage, if using the method obtain sodium acid carbonate as adsorbent as the process for purifying of fume desulfuring and denitrifying, its removal effect is unsatisfactory, simultaneously, obtain sodium acid carbonate crude product productive rate by the method lower, if adapt to the use amount of fume desulfuring and denitrifying technique adsorbent, not only to increase its commercial scale, also to increase crude product cleaning procedure simultaneously, the cost that has improved greatly whole preparation technology drops into, for this reason, the present invention arises at the historic moment.

Summary of the invention

The object of the present invention is to provide a kind of caprolactam that utilizes to burn the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, this preparation method utilizes caprolactam to burn salkali waste to react the Na generating with flue gas₂SO₄Solution, then react with carbonic hydroammonium and obtain the method for sodium acid carbonate, the Na in reaction raw materials₂SO₄Come from the circulation cleaning that caprolactam burns the smoke mixture of salkali waste and flue gas composition, realize and utilized salkali waste to administer waste gas, the object of the treatment of wastes with processes of wastes against one another, in addition, the method also can obtain and be worth higher sodium acid carbonate product, so not only save the energy, reduce and pollute, but also reduced the cost of gas cleaning and avoided the secondary pollution of gas cleaning.

The present invention is achieved through the following technical solutions: a kind of caprolactam that utilizes burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, and the method is the smoke mixture of utilizing salkali waste and flue gas to mix, the Na obtaining after circulation cleaning₂SO₄Solution is prepared the process of sodium acid carbonate product, described salkali waste is that caprolactam burns salkali waste, described flue gas is coal-fired flue-gas, coking tail gas or sintering tail gas, realize and utilized salkali waste to administer waste gas, the object of the treatment of wastes with processes of wastes against one another, have and save the energy, reduce and pollute and reduce the advantage such as cost of gas cleaning, social benefit is very remarkable.

In the present invention, it is drying solid that described caprolactam burns salkali waste, by weight percentage, comprises following component:

Na₂CO₃：65～85%；

Na₂SO₄：15～30%；

NaCl:2～5%, certainly, in the time that reality is used, caprolactam burns salkali waste and also includes other impurity such as free carbon, insoluble matter.

Further, the pollutant in described flue gas comprises following component:

SO_X：1000～5000mg/Nm³, wherein, X chooses 2 or 3;

NO_Y：200～600mg/Nm³, wherein, Y chooses 1 or 2.

The method comprises the steps:

A: prepare metabisulfite solution: salkali waste is mixed with flue gas phase, obtain smoke mixture after the pollutant in purifying flue gas, then this smoke mixture is carried out to circulation cleaning, and obtain Na₂SO₄Concentration content is 24～28% cleaning solution;

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor, after reacting, obtains sodium acid carbonate suspension with carbonic hydroammonium;

C: purify: sodium acid carbonate suspension is purified, obtain sodium acid carbonate product.

Comprehensive above-mentioned steps is known, and the present invention utilizes salkali waste to react the cleaning solution obtaining with flue gas, reacts the process that makes sodium acid carbonate, the Na in reaction raw materials with carbonic hydroammonium₂SO₄Come from flue gas through the thick purification of salkali waste and follow-up circulation cleaning, the pollutant of removing in flue gas can obtain the flue gas the discharge that meet discharge standard, cleaning solution reaches after finite concentration, delivers to sodium acid carbonate unit and complete the preparation of follow-up sodium acid carbonate.

Further, above-mentioned steps A comprises following two kinds of modes of operation:

(I) described steps A comprises:

(A.1) salkali waste is sent into pulverizer and pulverize, after pulverizing, obtaining granularity is 300～400 object salkali waste particles;

(A.2) salkali waste particle above-mentioned steps being obtained is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, send into again after metering dry powder injector, and utilize dry powder injector by salkali waste uniform particles spurt in flue gas, and realize fully the mixing of salkali waste and flue gas, reaction, and form smoke mixture, in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, certainly, for better improving the mixing efficiency of salkali waste particle and flue gas, the present invention is also provided with deduster at top, salkali waste powder storehouse, and bottom is provided with rapping apparatus, prevents that caking from appearring in the bulkhead in salkali waste powder storehouse;

(A.3) set up the absorption tower that is furnished with spraying layer, and on this spraying layer, be provided with the nozzle that carries out doctor solution spray from top to bottom, described smoke mixture is sent in tower through middle part, absorption tower, and contacts with doctor solution spraying, obtains SO after reaction₂Content is less than 100mg/Nm³、NO_YContent is 55～200mg/Nm³Flue gas thing, the temperature in absorption tower is 50～60 DEG C, humidity is 95～99%;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing again, after reacting with oxidation solution, obtain SO₂Content is less than 100mg/Nm³、NO_YContent is less than 100mg/Nm³Flue gas and Na₂SO₄Concentration content is 24～28% cleaning solution, and described flue gas is directly discharged by flue, and cleaning solution is delivered to sodium acid carbonate unit, the operation of completing steps B.

(II) described steps A comprises:

(A.2) salkali waste particle above-mentioned steps being obtained is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, send into again after metering dry powder injector, and utilize dry powder injector by salkali waste uniform particles spurt in flue gas, and realize fully the mixing of salkali waste and flue gas, reaction, and form smoke mixture;

(A.3) set up the absorption tower that is furnished with spraying layer, and on this spraying layer, be provided with the nozzle that carries out doctor solution spray from top to bottom, described smoke mixture is sent in tower through middle part, absorption tower, and contacts with doctor solution spraying, obtains SO after reaction₂Content is less than 100mg/Nm³、NO_YContent is 60～200mg/Nm³Flue gas thing, the temperature in absorption tower is 50～60 DEG C, humidity is 95～99%;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing again, after reacting with oxidation solution, obtain SO₂Content is less than 100mg/Nm³、NO_YContent is less than 100mg/Nm³Flue gas and Na₂SO₄Concentration content is 24～28% cleaning solution, and described flue gas is directly discharged by flue;

(A.5) cleaning solution that uses settling agent to obtain step (A.4) is clarified, and by weight, the addition of described settling agent and the ratio of cleaning solution are (1～5): 1000;

(A.6) cleaning solution after clarification is delivered to filter press by excavationg pump and filter, the metabisulfite solution obtaining after filtration is delivered to sodium acid carbonate unit again, the operation of completing steps B.

(II) planted mode of operation and planted mode of operation compared with (I); step (A.5) and (A.6) are increased; its object is: in actual application; caprolactam burns in salkali waste and conventionally also comprises the material such as free carbon, insoluble matter impurity; therefore, making for improving Na in cleaning solution of employing settling agent₂SO₄Degree of purity, thereby obtain higher-quality sodium acid carbonate.

In aforesaid operations mode (II), described settling agent is polyacrylamide, polyacrylamide sodium or bodied ferric sulfate, taking polyacrylamide (being called for short PAM) as example, above-mentioned steps can be summarized as follows: polyacrylamide is a kind of water-soluble linear macromolecule material, to be formed by monomer acrylamide polymerization, its molecular weight is from thousand to more than millions of, can make suspended material through charge neutrality, bridge formation adsorption effect, play flocculating effect, therefore, in cleaning solution, add polyacrylamide after 3-5 seconds, free carbon and insoluble matter impurity i.e. cohesion rapidly, then filter by filter press (as: flame filter press), the metabisulfite solution obtaining after filtration is very limpid, filter cake can be used as solid waste and is transported to slag field.

To better implement the present invention, by weight, described salkali waste and the mixing ratio of flue gas are 10000mg/Nm³, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：300～1500mg/Nm³、NO_Y：60～200mg/Nm³。

In described step B, in cleaning solution, sodium ion and carbonic hydroammonium are in mole ratio 1:(0.5～1.5) ratio be added in reactor, 35～40 DEG C of temperature, under the condition of reaction time 40～60min, obtain sodium acid carbonate suspension, optimize, in cleaning solution, the mol ratio of sodium ion and carbonic hydroammonium is 1:1.03.

In described step C, sodium acid carbonate suspension is after band filter washing is purified, drying obtains sodium acid carbonate product, in the present invention, band filter is mainly by dehydration belt, filter cloth, wear-resistant strip, vacuum pan, material feeding box, device for discharging, washing equipment, the parts compositions such as framework and band machine actuating device, band filter passes through feeding, filter, washing, de-slag, filter cloth regeneration can complete continuously automatically, automaticity is high, can carry out multistage advection or countercurrent washing to material, filtered fluid (mother liquor) and cleaning solution can separate liquid collecting, save washing lotion and guarantee quality simultaneously.

The present invention compared with prior art, has the following advantages and beneficial effect:

(1) the present invention be utilize that salkali waste reacts with flue gas, generate after mixing, washing contain certain density Na₂SO₄Cleaning solution, then react with carbonic hydroammonium and obtain the preparation method of sodium acid carbonate, the Na in reaction raw materials₂SO₄The circulation cleaning that comes from the hybrid reaction of salkali waste and flue gas and flue gaseous mixture is carried out, has realized and has utilized salkali waste to administer waste gas, and the object of the treatment of wastes with processes of wastes against one another, has solved the pollution of salkali waste to environment thoroughly, and social benefit is very remarkable.

(2) the present invention applicable to stack gas cleaning field, that is: uses salkali waste, as pretreating agent, flue gas is carried out to thick purification and removes SO₃And most of SO₂With a part of NO_YAfter, desulphurization denitration processing is carried out to flue gaseous mixture in recycling absorption tower, deviates from remaining SO₂And NO_YAfter, reaching the flue gas that meets national discharge index can directly discharge, and absorption tower absorbs SO₂The cleaning solution obtaining can arrange to deliver to sodium acid carbonate unit, for the preparation of sodium acid carbonate, in having solved the pollution of salkali waste to environment and having realized the purified treatment of flue gas, more effective discharge and the processing that has solved cleaning solution in stack gas cleaning process field, effectively control the industrial cost of stack gas cleaning, suitablely extensively promoted the use of.

(3) the present invention, in the governance process that is applicable to flue gas, also has good practical application effect, and first, salkali waste is sprayed in flue gas by injector after crushed, after abundant hybrid reaction, can remove the SO in flue gas₃And most of SO₂With a part of NO_Y, this step can effectively improve the denitrification efficiency of follow-up doctor solution in absorption tower, improves the purification efficiency of flue gas, and in actual use, the purifying rate of flue gas can be up to 98%.

(4) the present invention can realize the suitability for industrialized production of sodium acid carbonate in stack gas cleaning; its industrialization design is reasonable; adopt successively absorption tower, reactor to be formed by combining; not only can realize the purified treatment of flue gas; also can realize the production of sodium acid carbonate scale, and can obtain the sodium acid carbonate product that value is higher, simultaneously; more reduced the holistic cost of stack gas cleaning, economic benefit is very remarkable.

(5) the present invention is reasonable in design, particularly, for the metathesis product ammonium sulfate obtaining in sodium acid carbonate unit, also can recycle, and not only saves the energy, reduces and pollutes, but also and avoid the secondary pollution of gas cleaning.

Brief description of the drawings

Fig. 1 is process structure schematic diagram of the present invention.

Detailed description of the invention

Below goal of the invention of the present invention, technical scheme and beneficial effect are described in further detail.

Should be noted that, it is all exemplary below describing in detail, be intended for the requested to provide further explanation of the invention, except as otherwise noted, all technology used herein and scientific terminology have the identical meanings of conventionally understanding with general technical staff of the technical field of the invention.

Along with the continuous enhancing of environmental consciousness, at present, the improvement that people pollute industrial smoke and the regeneration of solid waste have become the emphasis of current environment protection, solid waste is scientifically recycled, then applied in the improvement of flue gas, can realize " the treatment of wastes with processes of wastes against one another, turn waste into wealth " regulation effect, existing Social benefit and economic benefit, have more important environment protection significance, for example: the method for existing patent documentation CN101570370(high resource treatment of cyclohexanone waste saponification lye, what 2009-11-04) disclose utilizing the carbon dioxide reaction in cyclohexanone spent lye and flue gas and obtains the method for sodium acid carbonate, not only reach the technological effect for the treatment of of wastes with processes of wastes against one another zero-emission, simultaneously, also can obtain crude product sodium acid carbonate, but be proven, the quality that is obtained sodium acid carbonate by the method also rests on the crude product stage, practical application effect and industrialized large-scale production are poor, and based on " the treatment of wastes with processes of wastes against one another, turn waste into wealth " industrial object, the present invention proposes a kind of caprolactam that utilizes and burn the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, the method is to react with flue gas by salkali waste successively, circulation cleaning acquisition contain finite concentration Na₂SO₄Cleaning solution after, then react with carbonic hydroammonium and make the preparation process of sodium acid carbonate product, its advantage main manifestations in the following areas:

(1) utilize dry salkali waste slightly to purify flue gas, realized the regeneration of solid waste, reached the object of " treatment of wastes with processes of wastes against one another ";

(2) realized the improvement of flue gas, the smoke mixture after thick purification, after circulation cleaning, can not only realize the fume emission that meets discharging standards, also can obtain cleaning solution (that is: the Na that concentration content is 24～28% of certain concentration content₂SO₄Solution);

(3) overcome the processing to cleaning solution in original stack gas cleaning process, the raw materials using cleaning solution as sodium acid carbonate, has realized " turning waste into wealth ";

(4) at Na₂SO₄In the metathesis reaction process of carbonic hydroammonium, the recycling for metathesis product ammonium sulfate has also been proposed, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit;

Below further describing technical solution of the present invention:

The present invention relates to following steps:

A: prepare metabisulfite solution:

(A.1) will be dried salkali waste and send into pulverizer and pulverize, after pulverizing, obtaining granularity is 300～400 object salkali waste particles, and by weight, dry salkali waste includes 50～85% Na₂CO₃, 12～35% Na₂SO₄, other impurity such as 1～15% NaCl, free carbon, insoluble matter, further, salkali waste is that caprolactam burns salkali waste;

(A.2) salkali waste particle above-mentioned steps being obtained is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, deduster is established at top, salkali waste powder storehouse, rapping apparatus is established in bottom, prevent the bulkhead caking in salkali waste powder storehouse, send into again after metering dry powder injector, and utilize dry powder injector by salkali waste uniform particles spurt in flue gas, and realize fully mixing of salkali waste and flue gas, wherein, flue gas can be selected coal-fired flue-gas, coking tail gas or sintering tail gas, and its pollutant comprises following component: SO_X：1000～5000mg/Nm³, (X chooses 2 or 3), NO_Y：200～600mg/Nm³, (Y chooses 1 or 2), in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, in actual mechanical process, by weight, the mixing ratio of salkali waste and flue gas is 10000mg/Nm³, remove the SO in flue gas₃After, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：300～1500mg/Nm³、NO_Y：60～200mg/Nm³, its reaction equation comprises:

Na₂CO₃+SO₂?Na₂SO₃+CO₂①

Na₂CO₃+SO₂+?O₂?Na₂SO₄+CO₂②

Na₂CO₃+SO₃→Na₂SO₄+CO₂③

4Na₂SO₃+2NO₂?4Na₂SO₄+N₂④

2NO+2SO₂?2SO₃+N₂⑤

(A.3) smoke mixture step (A.2) reaction being obtained is sent into and in absorption tower, is carried out circulation cleaning, in absorption tower, be furnished with three layers of spraying layer, doctor solution is after circulating pump pressurization, the nozzle distributing from spraying layer is ejection at a high speed, and form the desulfurization droplet that a large amount of specific areas is larger, on the one hand, smoke mixture enters the middle part on absorption tower, rapid decreasing temperature and increasing humidity in tower, and meet head on to contact with the desulfurization droplet of reverse high-speed motion, strong action of turbulent flow occurs, and gas, liquid two-phase are carried out abundant mass-and heat-transfer, the SO in smoke mixture₂Absorbed in a large number; On the other hand, salkali waste particle in smoke mixture is sailed against the current with air-flow after entering in tower equally, contacts fully with top-down doctor solution, excessive salkali waste grain dissolution, in doctor solution, circulates in tower with desulfurization slurry and continues to absorb residual SO in flue gas₂、NO_YAnd heavy metallic oxide, owing to distributing rationally, the spray mist cone that three layers of nozzle produces can reach more than 200% the coverage rate in desulfurizing tower cross section, has guaranteed the removal efficiency of sulfur dioxide, its eliminating efficiency can be up to 98%, after spray can after obtain SO₂The little 100mg/Nm of content³、NO_YContent is 55～200mg/Nm³Flue gas thing, 50～60 DEG C of the temperature in absorption tower, humidity is 95～99%, doctor solution can be selected the mixture of one or more compositions in sodium carbonate, sodium sulphate, sodium nitrate;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing, after reacting with oxidation solution, the NO in flue gas thing_YOxidized liquid oxidation absorbs, and obtains SO₂Content is less than 100mg/Nm³、NO_YContent is less than 100mg/Nm³Flue gas and desulfurization slurry (that is: cleaning solution), flue gas reaches discharging standards and can directly be discharged by flue, cleaning solution, in circulation cleaning process, constantly absorbs SO₂, progressively increase in the concentration of absorption tower oxidation panel cleaning solution, in the time reaching 24～28%, deliver to filter press by excavationg pump, filter out after the free carbon and other impurity in salkali waste, then by this filtrate (that is: Na that concentration is 24～28%₂SO₄Solution) deliver to sodium acid carbonate unit, the operation of completing steps B.

In actual mechanical process, for guaranteeing the product quality of sodium acid carbonate, the cleaning solution that step (A.4) is obtained also can take following steps to operate:

(A.5) cleaning solution that uses settling agent to obtain step (A.4) is clarified, by weight, the addition of described settling agent and the ratio of cleaning solution are (1～5): 1000, wherein, settling agent can be selected polyacrylamide, polyacrylamide sodium or bodied ferric sulfate, be mainly used in removing the free carbon containing in cleaning solution, the materials such as insoluble matter impurity, taking water-soluble linear macromolecule material---polyacrylamide (being called for short PAM) is as example, polyacrylamide is to be formed by monomer acrylamide polymerization, its molecular weight is from thousand to more than millions of, can make suspended material through charge neutrality, bridge formation adsorption effect, play flocculating effect, therefore, in cleaning solution, add polyacrylamide after 3～5 seconds, free carbon and insoluble matter impurity i.e. cohesion rapidly,

(A.6) cleaning solution after above-mentioned clarification being delivered to filter press (as: flame filter press) by excavationg pump filters, the metabisulfite solution obtaining after filtration is very limpid, again this metabisulfite solution is delivered to sodium acid carbonate unit, the operation of completing steps B, filter cake can be used as solid waste and is transported to slag field.

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor (as: double decomposition reactor), after reacting with carbonic hydroammonium, obtain sodium acid carbonate suspension, wherein, in cleaning solution, sodium ion and carbonic hydroammonium are in mole ratio 1:(0.5～1.5) ratio be added in reactor, 35～40 DEG C of temperature, under the condition of reaction time 40～60min, obtain sodium acid carbonate suspension, simultaneously, recycle for metathesis reaction accessory substance ammonium sulfate, for example, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit, its reaction equation is as follows:

Na₂SO₄+2NH₄HCO₃?2NaHCO₃+(NH₄)₂SO₄⑥

C: purify: sodium acid carbonate suspension is purified, comprise: sodium acid carbonate suspension is after band filter washing is purified, drying obtains sodium acid carbonate product, in the present invention, band filter is mainly by dehydration belt, filter cloth, wear-resistant strip, vacuum pan, material feeding box, device for discharging, washing equipment, the parts compositions such as framework and band machine actuating device, band filter passes through feeding, filter, washing, de-slag, filter cloth regeneration can complete continuously automatically, automaticity is high, can carry out multistage advection or countercurrent washing to material, filtered fluid (mother liquor) and cleaning solution can separate liquid collecting, save washing lotion and guarantee quality simultaneously.

Comprehensive above-mentioned steps is known, and the present invention utilizes salkali waste to react the cleaning solution of acquisition with flue gas, then reacts with carbonic hydroammonium and make the process of sodium acid carbonate, the Na in reaction raw materials₂SO₄Come from thick purification and the absorption tower circulation cleaning to smoke mixture of flue gas through salkali waste, the pollutant of removing in flue gas obtains flue gas discharge, cleaning solution reaches after finite concentration, deliver to the preparation that sodium acid carbonate unit completes follow-up sodium acid carbonate, not only realize and utilized salkali waste to administer waste gas, the object of the treatment of wastes with processes of wastes against one another, in addition, the method also can obtain and be worth higher sodium acid carbonate product, so not only save the energy, reduce and pollute, but also reduced the cost of gas cleaning and avoided the secondary pollution of gas cleaning.

Enumerate explanation the specific embodiment of the present invention with several exemplary embodiments below, certainly, protection scope of the present invention is not limited to following examples.

Embodiment 1:

The preparation method that the present embodiment relates to is the smoke mixture of utilizing salkali waste and flue gas to mix, the Na obtaining after circulation cleaning₂SO₄Solution is prepared the process of sodium acid carbonate product, and salkali waste selects caprolactam to burn salkali waste, and flue gas is selected coal-fired flue-gas.

Embodiment 2:

The difference of the present embodiment and embodiment 1 is: it is drying solid that the caprolactam of selecting burns salkali waste, by weight percentage, comprises 65% Na₂CO₃, 30% Na₂SO₄And 5% NaCl.

Embodiment 3:

The difference of the present embodiment and embodiment 1 is: flue gas can be selected sintering tail gas, and in this sintering tail gas, pollutant includes: 5000mg/Nm³SO_X(as: SO₂、SO₃) and 600mg/Nm³NO_Y(as: NO, NO₂）。

Embodiment 4:

The preparation method that the present embodiment relates to is the smoke mixture of utilizing salkali waste and flue gas to mix, the Na obtaining after circulation cleaning₂SO₄Solution is prepared the process of sodium acid carbonate product, and salkali waste selects caprolactam to burn salkali waste, and flue gas is selected coking tail gas.

The present embodiment relates to following steps:

A: prepare metabisulfite solution: salkali waste is mixed with flue gas phase, obtain smoke mixture after the pollutant in purifying flue gas, then this smoke mixture is carried out to circulation cleaning, and obtain Na₂SO₄Concentration content is 24% cleaning solution;

Embodiment 5:

The present embodiment is applicable to the purification of coal-fired flue-gas, and wherein, the salkali waste of selecting is that caprolactam burns salkali waste, comprises following component: 50% Na₂CO₃, 35% Na₂SO₄, other impurity (as: NaCl, free carbon and insoluble matter etc.) of 15%; Coal-fired flue-gas is mainly derived from the waste gas that Industrial Boiler, thermal power plant etc. produce, and pollutant wherein includes: 5000mg/Nm³SO_XAnd 600mg/Nm³NO_Y。

The present embodiment relates to following steps:

A: prepare metabisulfite solution:

(A.1) above-mentioned dry salkali waste is sent into pulverizer and pulverize, after pulverizing, obtaining granularity is 300 object salkali waste particles;

(A.2) salkali waste particle is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, and deduster is established at top, salkali waste powder storehouse, and rapping apparatus is established in bottom, prevent the bulkhead caking in salkali waste powder storehouse, salkali waste particle is according to remaining SO in smoke mixture after injection desulfurization (slightly purifying)₂And NO_YAmount is measured, and by weight, the mixing ratio of salkali waste and flue gas is pressed 10000mg/Nm³Ratio send into dry powder injector, and then spurt into equably in flue gas, realize fully mixing of salkali waste and flue gas, in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, and remove the SO in flue gas₃After, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：1500mg/Nm³、NO_Y：200mg/Nm³；

(A.3) smoke mixture step (A.2) reaction being obtained is sent into and in absorption tower, is carried out circulation cleaning, in absorption tower, be furnished with three layers of spraying layer, doctor solution (as: sodium carbonate) is after circulating pump pressurization, the nozzle distributing from spraying layer is ejection at a high speed, and form the desulfurization droplet that a large amount of specific areas is larger, on the one hand, smoke mixture enters the middle part on absorption tower, rapid decreasing temperature and increasing humidity in tower, and meet head on to contact with the desulfurization droplet of reverse high-speed motion, strong action of turbulent flow occurs, and gas, liquid two-phase are carried out abundant mass-and heat-transfer, the SO in smoke mixture₂Absorbed in a large number; On the other hand, salkali waste particle in smoke mixture is sailed against the current with air-flow after entering in tower equally, contacts fully with top-down doctor solution, excessive salkali waste grain dissolution, in doctor solution, circulates in tower with desulfurization slurry and continues to absorb residual SO in flue gas₂、NO_YAnd heavy metallic oxide, owing to distributing rationally, the spray mist cone that three layers of nozzle produces can reach more than 200% the coverage rate in desulfurizing tower cross section, has guaranteed the removal efficiency of sulfur dioxide, its eliminating efficiency is 98%, after spray can after obtain SO₂Content is 100mg/Nm³、NO_YFor 200mg/Nm³Flue gas thing, the temperature in absorption tower is 60 DEG C, humidity is 99%;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing, after reacting with oxidation solution,, the NO in flue gas thing_YOxidized liquid oxidation absorbs, and obtains SO₂Content is 100mg/Nm³、NO_YFor 100mg/Nm³Flue gas and desulfurization slurry (that is: cleaning solution), flue gas reaches discharging standards and can directly be discharged by flue, cleaning solution, in circulation cleaning process, constantly absorbs SO₂, progressively increase in the concentration of absorption tower oxidation panel cleaning solution, in the time reaching 24%, deliver to filter press by excavationg pump, filter out after the free carbon and other impurity in salkali waste, then by this filtrate (that is: Na that concentration is 24%₂SO₄Solution) deliver to sodium acid carbonate unit, the operation of completing steps B.

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor (as: double decomposition reactor), after reacting with carbonic hydroammonium, obtain sodium acid carbonate suspension, wherein, in cleaning solution, sodium ion and carbonic hydroammonium are added in reactor in the ratio of mole ratio 1:1.5, 40 DEG C of temperature, under the condition of reaction time 60min, obtain sodium acid carbonate suspension, simultaneously, recycle for metathesis reaction accessory substance ammonium sulfate, for example, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit.

Above-mentioned steps is calculated and add up known, and in the present embodiment, the productive rate of sodium acid carbonate product is 74.5%.

Embodiment 6:

The present embodiment is applicable to the purification of coking tail gas, and wherein, the salkali waste of selecting is that caprolactam burns salkali waste, comprises following component: 85% Na₂CO₃, 12% Na₂SO₄, other impurity (as: NaCl, free carbon and insoluble matter etc.) of 3%; Coking tail gas is mainly derived from the waste gas of the generations such as coking industry, and pollutant wherein includes: 1000mg/Nm³SO_XAnd 200mg/Nm³NO_Y。

The present embodiment relates to following steps:

A: prepare metabisulfite solution:

(A.1) above-mentioned dry salkali waste is sent into pulverizer and pulverize, after pulverizing, obtaining granularity is 400 object salkali waste particles;

(A.2) salkali waste particle is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, and deduster is established at top, salkali waste powder storehouse, and rapping apparatus is established in bottom, prevent the bulkhead caking in salkali waste powder storehouse, salkali waste particle is according to remaining SO in smoke mixture after injection desulfurization (slightly purifying)₂And NO_YAmount measure, by weight, salkali waste by with the mixing ratio of flue gas be 10000mg/Nm³Ratio send into dry powder injector, and then spurt into equably in flue gas, realize fully mixing of salkali waste and flue gas, in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, and remove the SO in flue gas₃After, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：300mg/Nm³、NO_Y：60mg/Nm³；

(A.3) smoke mixture step (A.2) reaction being obtained is sent into and in absorption tower, is carried out circulation cleaning, in absorption tower, be furnished with three layers of spraying layer, doctor solution (as: sodium sulphate) is after circulating pump pressurization, the nozzle distributing from spraying layer is ejection at a high speed, and form the desulfurization droplet that a large amount of specific areas is larger, on the one hand, smoke mixture enters the middle part on absorption tower, rapid decreasing temperature and increasing humidity in tower, and meet head on to contact with the desulfurization droplet of reverse high-speed motion, strong action of turbulent flow occurs, and gas, liquid two-phase are carried out abundant mass-and heat-transfer, the SO in smoke mixture₂Absorbed in a large number; On the other hand, salkali waste particle in smoke mixture is sailed against the current with air-flow after entering in tower equally, contacts fully with top-down doctor solution, excessive salkali waste grain dissolution, in doctor solution, circulates in tower with desulfurization slurry and continues to absorb residual SO in flue gas₂、NO_YAnd heavy metallic oxide, owing to distributing rationally, the spray mist cone that three layers of nozzle produces can reach more than 200% the coverage rate in desulfurizing tower cross section, has guaranteed the removal efficiency of sulfur dioxide, its eliminating efficiency can reach 97%, after spray can after obtain SO₂Content is 30mg/Nm³、NO_YContent is 55mg/Nm³Flue gas thing, the temperature in absorption tower is 50 DEG C, humidity is 95%;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing, after reacting with oxidation solution,, the NO in flue gas thing_YOxidized liquid oxidation absorbs, and obtains SO₂Content is 30mg/Nm³、NO_YContent is 25mg/Nm³Flue gas and desulfurization slurry (that is: cleaning solution), flue gas reaches discharging standards and can directly be discharged by flue, cleaning solution, in circulation cleaning process, constantly absorbs SO₂, progressively increase in the concentration of absorption tower oxidation panel cleaning solution, in the time reaching 28%, deliver to filter press by excavationg pump, filter out after the free carbon and other impurity in salkali waste, then by this filtrate (that is: Na that concentration is 28%₂SO₄Solution) deliver to sodium acid carbonate unit, the operation of completing steps B.

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor (as: double decomposition reactor), after reacting with carbonic hydroammonium, obtain sodium acid carbonate suspension, wherein, in cleaning solution, sodium ion and carbonic hydroammonium are added in reactor in the ratio of mole ratio 1:0.5, 35 DEG C of temperature, under the condition of reaction time 40min, obtain sodium acid carbonate suspension, simultaneously, recycle for metathesis reaction accessory substance ammonium sulfate, for example, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit.

Above-mentioned steps is calculated and add up known, and in the present embodiment, the productive rate of sodium acid carbonate product is 76%.

Embodiment 7:

The present embodiment is applicable to the purification of sintering tail gas, and wherein, the salkali waste of selecting is that caprolactam burns salkali waste, comprises following component: 67% Na₂CO₃, 32% Na₂SO₄, other impurity (as: NaCl, free carbon and insoluble matter etc.) of 1%; Sintering tail gas is mainly derived from the waste gas of the generations such as steel and iron industry, and pollutant wherein includes: 4000mg/Nm³SO_XAnd 500mg/Nm³NO_Y。

The present embodiment relates to following steps:

A: prepare metabisulfite solution:

(A.1) above-mentioned dry salkali waste is sent into pulverizer and pulverize, after pulverizing, obtaining granularity is 350 object salkali waste particles;

(A.2) salkali waste particle is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, and deduster is established at top, salkali waste powder storehouse, and rapping apparatus is established in bottom, prevent the bulkhead caking in salkali waste powder storehouse, salkali waste particle is according to remaining SO in smoke mixture after injection desulfurization (slightly purifying)₂And NO_YAmount measure, by weight, salkali waste by with the mixing ratio of flue gas be 10000mg/Nm³Ratio send into dry powder injector, and then spurt into equably in flue gas, realize fully mixing of salkali waste and flue gas, in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, and remove the SO in flue gas₃After, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：1200mg/Nm³、NO_Y：150mg/Nm³；

(A.3) smoke mixture step (A.2) reaction being obtained is sent into and in absorption tower, is carried out circulation cleaning, in absorption tower, be furnished with three layers of spraying layer, doctor solution (as: sodium nitrate) is after circulating pump pressurization, the nozzle distributing from spraying layer is ejection at a high speed, and form the desulfurization droplet that a large amount of specific areas is larger, on the one hand, smoke mixture enters the middle part on absorption tower, rapid decreasing temperature and increasing humidity in tower, and meet head on to contact with the desulfurization droplet of reverse high-speed motion, strong action of turbulent flow occurs, and gas, liquid two-phase are carried out abundant mass-and heat-transfer, the SO in smoke mixture₂Absorbed in a large number; On the other hand, salkali waste particle in smoke mixture is sailed against the current with air-flow after entering in tower equally, contacts fully with top-down doctor solution, excessive salkali waste grain dissolution, in doctor solution, circulates in tower with desulfurization slurry and continues to absorb residual SO in flue gas₂、NO_YAnd heavy metallic oxide, owing to distributing rationally, the spray mist cone that three layers of nozzle produces can reach more than 200% the coverage rate in desulfurizing tower cross section, has guaranteed the removal efficiency of sulfur dioxide, its eliminating efficiency can reach 97.8%, after spray can after obtain SO₂Content is 88mg/Nm³、NO_YContent is 120mg/Nm³Flue gas thing, the temperature in absorption tower is 55 DEG C, humidity is 98%;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing, after reacting with oxidation solution,, the NO in flue gas thing_YOxidized liquid oxidation absorbs, and obtains SO₂Content is 88mg/Nm³、NO_YContent is 90mg/Nm³Flue gas and desulfurization slurry (that is: cleaning solution), flue gas reaches discharging standards and can directly be discharged by flue;

(A.5) cleaning solution, in circulation cleaning process, constantly absorbs SO₂, progressively increase in the concentration of absorption tower oxidation panel cleaning solution, as Na in cleaning solution₂SO₄Concentration while reaching 26%, use settling agent to clarify this cleaning solution, by weight, the addition of settling agent and the ratio of cleaning solution are 1:1000, wherein, settling agent can be selected polyacrylamide, be mainly used in removing the free carbon containing in cleaning solution, the materials such as insoluble matter impurity, taking water-soluble linear macromolecule material---polyacrylamide (being called for short PAM) is as example, polyacrylamide is to be formed by monomer acrylamide polymerization, its molecular weight is from thousand to more than millions of, can make suspended material through charge neutrality, bridge formation adsorption effect, play flocculating effect, therefore, in cleaning solution, add polyacrylamide after 3 seconds, free carbon and insoluble matter impurity i.e. cohesion rapidly,

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor (as: double decomposition reactor), after reacting with carbonic hydroammonium, obtain sodium acid carbonate suspension, wherein, in cleaning solution, sodium ion and carbonic hydroammonium are added in reactor in the ratio of mole ratio 1:1.03, 38 DEG C of temperature, under the condition of reaction time 55min, obtain sodium acid carbonate suspension, simultaneously, recycle for metathesis reaction accessory substance ammonium sulfate, for example, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit.

Above-mentioned steps is calculated and add up known, and in the present embodiment, the productive rate of sodium acid carbonate product is 73.5%.

Embodiment 8:

The present embodiment is applicable to the purification of sintering tail gas, and wherein, the salkali waste of selecting is that caprolactam burns salkali waste, comprises following component: 65% Na₂CO₃, 30% Na₂SO₄, 4% NaCl and other impurity (as: free carbon and insoluble matter etc.) of 1%; Sintering tail gas is mainly derived from the waste gas of the generations such as steel and iron industry, and pollutant wherein includes: 3000mg/Nm³SO_XAnd 400mg/Nm³NO_Y。

The present embodiment relates to following steps:

A: prepare metabisulfite solution:

(A.1) above-mentioned dry salkali waste is sent into pulverizer and pulverize, after pulverizing, obtaining granularity is 320 object salkali waste particles;

(A.2) salkali waste particle is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, and deduster is established at top, salkali waste powder storehouse, and rapping apparatus is established in bottom, prevent the bulkhead caking in salkali waste powder storehouse, salkali waste particle is according to remaining SO in smoke mixture after injection desulfurization (slightly purifying)₂And NO_YAmount measure, by weight, salkali waste by with the mixing ratio of flue gas be 10000mg/Nm³Ratio send into dry powder injector, and then spurt into equably in flue gas, realize fully mixing of salkali waste and flue gas, in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, and remove the SO in flue gas₃After, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：900mg/Nm³、NO_Y：120mg/Nm³；

(A.3) smoke mixture step (A.2) reaction being obtained is sent into and in absorption tower, is carried out circulation cleaning, in absorption tower, be furnished with three layers of spraying layer, doctor solution (as: sodium carbonate, sodium sulphate, the mixture of sodium nitrate composition) after circulating pump pressurization, the nozzle distributing from spraying layer is ejection at a high speed, and form the desulfurization droplet that a large amount of specific areas is larger, on the one hand, smoke mixture enters the middle part on absorption tower, rapid decreasing temperature and increasing humidity in tower, and meet head on to contact with the desulfurization droplet of reverse high-speed motion, there is strong action of turbulent flow, gas, liquid two-phase is carried out abundant mass-and heat-transfer, SO in smoke mixture₂Absorbed in a large number; On the other hand, salkali waste particle in smoke mixture is sailed against the current with air-flow after entering in tower equally, contacts fully with top-down doctor solution, excessive salkali waste grain dissolution, in doctor solution, circulates in tower with desulfurization slurry and continues to absorb residual SO in flue gas₂、NO_YAnd heavy metallic oxide, owing to distributing rationally, the spray mist cone that three layers of nozzle produces can reach more than 200% the coverage rate in desulfurizing tower cross section, has guaranteed the removal efficiency of sulfur dioxide, its eliminating efficiency can reach 98.5%, after spray can after obtain SO₂Content is 45mg/Nm³、NO_YContent is 100mg/Nm³Flue gas thing, the temperature in absorption tower is 58 DEG C, humidity is 99%, doctor solution can be selected;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing, after reacting with oxidation solution,, the NO in flue gas thing_YOxidized liquid oxidation absorbs, and obtains SO₂Content is 45mg/Nm³、NO_YContent is 60mg/Nm³Flue gas and desulfurization slurry (that is: cleaning solution), flue gas reaches discharging standards and can directly be discharged by flue;

(A.5) cleaning solution, in circulation cleaning process, constantly absorbs SO₂, progressively increase in the concentration of absorption tower oxidation panel cleaning solution, as Na in cleaning solution₂SO₄Concentration while reaching 25%, use settling agent to clarify this cleaning solution, by weight, the addition of settling agent and the ratio of cleaning solution are 5:1000, and wherein, settling agent can be selected polyacrylamide sodium, play flocculating effect, therefore, add polyacrylamide sodium after 5 seconds in cleaning solution, free carbon and insoluble matter impurity i.e. cohesion rapidly;

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor (as: double decomposition reactor), after reacting with carbonic hydroammonium, obtain sodium acid carbonate suspension, wherein, in cleaning solution, sodium ion and carbonic hydroammonium are added in reactor in the ratio of mole ratio 1:1.2, 39 DEG C of temperature, under the condition of reaction time 45min, obtain sodium acid carbonate suspension, simultaneously, recycle for metathesis reaction accessory substance ammonium sulfate, for example, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit.

Above-mentioned steps is calculated and add up known, and in the present embodiment, the productive rate of sodium acid carbonate product is 75%.

Embodiment 9:

The present embodiment is applicable to the purification of coking tail gas, and wherein, the salkali waste of selecting is that caprolactam burns salkali waste, comprises following component: 75% Na₂CO₃, 15% Na₂SO₄, 3% NaCl and other impurity (as: free carbon and insoluble matter etc.) of 7%; Coking tail gas is mainly derived from the waste gas of the generations such as coking industry, and pollutant wherein includes: 2000mg/Nm³SO_XAnd 300mg/Nm³NO_Y。

The present embodiment relates to following steps:

A: prepare metabisulfite solution:

(A.1) above-mentioned dry salkali waste is sent into pulverizer and pulverize, after pulverizing, obtaining granularity is 380 object salkali waste particles;

(A.2) salkali waste particle is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, and deduster is established at top, salkali waste powder storehouse, and rapping apparatus is established in bottom, prevent the bulkhead caking in salkali waste powder storehouse, salkali waste particle is according to remaining SO in smoke mixture after injection desulfurization (slightly purifying)₂And NO_YAmount measure, by weight, salkali waste by with the mixing ratio of flue gas be 10000mg/Nm³Ratio send into dry powder injector, and then spurt into equably in flue gas, realize fully mixing of salkali waste and flue gas, in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, and remove the SO in flue gas₃After, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：800mg/Nm³、NO_Y：110mg/Nm³；

(A.3) smoke mixture step (A.2) reaction being obtained is sent into and in absorption tower, is carried out circulation cleaning, in absorption tower, be furnished with three layers of spraying layer, doctor solution (as: sodium carbonate, the mixture of sodium sulphate composition) after circulating pump pressurization, the nozzle distributing from spraying layer is ejection at a high speed, and form the desulfurization droplet that a large amount of specific areas is larger, on the one hand, smoke mixture enters the middle part on absorption tower, rapid decreasing temperature and increasing humidity in tower, and meet head on to contact with the desulfurization droplet of reverse high-speed motion, there is strong action of turbulent flow, gas, liquid two-phase is carried out abundant mass-and heat-transfer, SO in smoke mixture₂Absorbed in a large number; On the other hand, salkali waste particle in smoke mixture is sailed against the current with air-flow after entering in tower equally, contacts fully with top-down doctor solution, excessive salkali waste grain dissolution, in doctor solution, circulates in tower with desulfurization slurry and continues to absorb residual SO in flue gas₂、NO_YAnd heavy metallic oxide, owing to distributing rationally, the spray mist cone that three layers of nozzle produces can reach more than 200% the coverage rate in desulfurizing tower cross section, has guaranteed the removal efficiency of sulfur dioxide, its eliminating efficiency can reach 98.3%, after spray can after obtain SO₂Content is 34mg/Nm³、NO_YContent is 100mg/Nm³Flue gas thing, the temperature in absorption tower is 55 DEG C, humidity is 99%;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing, after reacting with oxidation solution,, the NO in flue gas thing_YOxidized liquid oxidation absorbs, and obtains SO₂Content is 34mg/Nm³、NO_YContent is 48mg/Nm³Flue gas and desulfurization slurry (that is: cleaning solution), flue gas reaches discharging standards and can directly be discharged by flue;

(A.5) cleaning solution, in circulation cleaning process, constantly absorbs SO₂, progressively increase in the concentration of absorption tower oxidation panel cleaning solution, as Na in cleaning solution₂SO₄Concentration while reaching 27%, use settling agent to clarify this cleaning solution, by weight, the addition of settling agent and the ratio of cleaning solution are 4:1000, wherein, settling agent can be selected polyacrylamide, polyacrylamide sodium or bodied ferric sulfate, be mainly used in removing the free carbon containing in cleaning solution, the materials such as insoluble matter impurity, taking water-soluble linear macromolecule material---polyacrylamide (being called for short PAM) is as example, polyacrylamide is to be formed by monomer acrylamide polymerization, its molecular weight is from thousand to more than millions of, can make suspended material through charge neutrality, bridge formation adsorption effect, play flocculating effect, therefore, in cleaning solution, add polyacrylamide after 4 seconds, free carbon and insoluble matter impurity i.e. cohesion rapidly,

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor (as: double decomposition reactor), after reacting with carbonic hydroammonium, obtain sodium acid carbonate suspension, wherein, cleaning solution and carbonic hydroammonium are added in reactor by weight the ratio of 1:1.03, 38.5 DEG C of temperature, under the condition of reaction time 50min, obtain sodium acid carbonate suspension, simultaneously, recycle for metathesis reaction accessory substance ammonium sulfate, for example, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit.

Above-mentioned steps is calculated and add up known, and in the present embodiment, the productive rate of sodium acid carbonate product is 75.5%.

Embodiment 10:

The present embodiment is applicable to the purification of sintering tail gas, and wherein, the salkali waste of selecting is that caprolactam burns salkali waste, comprises following component: 70% Na₂CO₃, 24% Na₂SO₄, 2% NaCl and other impurity (as: free carbon and insoluble matter etc.) of 4%; Sintering tail gas is mainly derived from the waste gas of the generations such as steel and iron industry, and pollutant wherein includes: 3500mg/Nm³SO_XAnd 450mg/Nm³NO_Y。

The present embodiment relates to following steps:

A: prepare metabisulfite solution:

(A.1) above-mentioned dry salkali waste is sent into pulverizer and pulverize, after pulverizing, obtaining granularity is 390 object salkali waste particles;

(A.2) salkali waste particle is sent into charging hopper, and then send into salkali waste powder storehouse by gas-solid conveyer, and deduster is established at top, salkali waste powder storehouse, and rapping apparatus is established in bottom, prevent the bulkhead caking in salkali waste powder storehouse, salkali waste particle is according to remaining SO in smoke mixture after injection desulfurization (slightly purifying)₂And NO_YAmount measure, by weight, salkali waste by with the mixing ratio of flue gas be 10000mg/Nm³Ratio send into dry powder injector, and then spurt into equably in flue gas, realize fully mixing of salkali waste and flue gas, in this step, after the abundant haptoreaction of salkali waste particle and flue gas, can remove the SO in flue gas₃And most SO₂With a part of NO_Y, and remove the SO in flue gas₃After, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：1200mg/Nm³、NO_Y：120mg/Nm³；

(A.3) smoke mixture step (A.2) reaction being obtained is sent into and in absorption tower, is carried out circulation cleaning, in absorption tower, be furnished with three layers of spraying layer, doctor solution (as: sodium sulphate, the mixture of sodium nitrate composition) after circulating pump pressurization, the nozzle distributing from spraying layer is ejection at a high speed, and form the desulfurization droplet that a large amount of specific areas is larger, on the one hand, smoke mixture enters the middle part on absorption tower, rapid decreasing temperature and increasing humidity in tower, and meet head on to contact with the desulfurization droplet of reverse high-speed motion, there is strong action of turbulent flow, gas, liquid two-phase is carried out abundant mass-and heat-transfer, SO in smoke mixture₂Absorbed in a large number; On the other hand, salkali waste particle in smoke mixture is sailed against the current with air-flow after entering in tower equally, contacts fully with top-down doctor solution, excessive salkali waste grain dissolution, in doctor solution, circulates in tower with desulfurization slurry and continues to absorb residual SO in flue gas₂、NO_YAnd heavy metallic oxide, owing to distributing rationally, the spray mist cone that three layers of nozzle produces can reach more than 200% the coverage rate in desulfurizing tower cross section, has guaranteed the removal efficiency of sulfur dioxide, its eliminating efficiency can reach 99%, after spray can after obtain SO₂Content is 35mg/Nm³、NO_YContent is 150mg/Nm³Flue gas thing, the temperature temperature in absorption tower is 56 DEG C, humidity is 99%;

(A.4) above-mentioned flue gas thing is carried out sending into absorption tower oxidation panel after demist processing, after reacting with oxidation solution,, the NO in flue gas thing_YOxidized liquid oxidation absorbs, and obtains SO₂Content is 35mg/Nm³、NO_YContent is 60mg/Nm³Flue gas and desulfurization slurry (that is: cleaning solution), flue gas reaches discharging standards and can directly be discharged by flue, cleaning solution, in circulation cleaning process, constantly absorbs SO₂, progressively increase in the concentration of absorption tower oxidation panel cleaning solution, in the time reaching 26%, deliver to filter press by excavationg pump, filter out after the free carbon and other impurity in salkali waste, then by this filtrate (that is: Na that concentration is 26%₂SO₄Solution) deliver to sodium acid carbonate unit, the operation of completing steps B.

B: sodium acid carbonate unit: the cleaning solution that above-mentioned steps is obtained is sent in reactor (as: double decomposition reactor), after reacting with carbonic hydroammonium, obtain sodium acid carbonate suspension, wherein, in cleaning solution, sodium ion and carbonic hydroammonium are added in reactor in the ratio of mole ratio 1:1.1, 39 DEG C of temperature, under the condition of reaction time 45min, obtain sodium acid carbonate suspension, simultaneously, recycle for metathesis reaction accessory substance ammonium sulfate, for example, as: produce ammonium sulfate fertilizer etc., can not only realize the industrial production of zero-emission, and also there is good economic benefit.

Data to above-described embodiment 5～10 are added up, as shown in table 1:

Table 1

By the average data of above-described embodiment 5～10 and patent documentation CN101570370(documents 1) in data compare, as shown in table 2:

Table 2

The above, be only preferred embodiment of the present invention, not the present invention done to any pro forma restriction, and any simple modification, equivalent variations that every foundation technical spirit of the present invention is done above embodiment, within all falling into protection scope of the present invention.

Claims

1. utilize caprolactam to burn the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, it is characterized in that: the method is the smoke mixture of utilizing salkali waste and flue gas to mix the Na obtaining after circulation cleaning₂SO₄Solution is prepared the process of sodium acid carbonate product, described salkali waste is that caprolactam burns salkali waste, and described flue gas is coal-fired flue-gas, coking tail gas or sintering tail gas, and it is drying solid that described caprolactam burns salkali waste, by weight percentage, comprise following component:

Na₂CO₃：65～85%；

Na₂SO₄：15～30%；

NaCl：2～5%，

Pollutant in described flue gas comprises following component:

SO_X：1000～5000mg/Nm³, wherein, X chooses 2 or 3;

NO_Y：200～600mg/Nm³, wherein, Y chooses 1 or 2,

The method comprises the steps:

C: purify: sodium acid carbonate suspension is purified, obtain sodium acid carbonate product,

Described steps A comprises:

2. a kind of caprolactam that utilizes according to claim 1 burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, it is characterized in that: described steps A comprises:

3. a kind of caprolactam that utilizes according to claim 2 burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, it is characterized in that: described settling agent is polyacrylamide, polyacrylamide sodium or bodied ferric sulfate.

4. burn the method for converting waste caustic soda for sodium acid carbonate in gas cleaning according to a kind of caprolactam that utilizes described in claim 1～3 any one, it is characterized in that: by weight, described salkali waste and the mixing ratio of flue gas are 10000mg/Nm³, in the smoke mixture obtaining after hybrid reaction, the content of pollutant is: SO₂：300～1500mg/Nm³、NO_Y：60～200mg/Nm³。

5. a kind of caprolactam that utilizes according to claim 1 burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, it is characterized in that: in described step B, in cleaning solution, sodium ion and carbonic hydroammonium are in mole ratio 1:(0.5～1.5) ratio be added in reactor, 35～40 DEG C of temperature, under the condition of reaction time 40～60min, obtain sodium acid carbonate suspension.

6. a kind of caprolactam that utilizes according to claim 1 burns the method for converting waste caustic soda for sodium acid carbonate in gas cleaning, it is characterized in that: in described step C, sodium acid carbonate suspension is after band filter washing is purified, and drying obtains sodium acid carbonate product.