CN104740987B - A kind of resource ammonia desulfurizing process - Google Patents

Abstract

The invention discloses a kind of resource ammonia desulfurizing process, the technique is to generate ammonium bisulfite intermediate product as absorbent sulfur dioxide absorption flue gas using ammonium hydrogen carbonate, recycle the oxidation susceptibility of pyrolusite, pyrolusite is reduced with ammonium bisulfite intermediate product, is carbonized, while obtaining high-quality manganese carbonate and ammonium sulfate product；The sulfur dioxide flue gas of the process choice, ammonium hydrogen carbonate and pyrolusite raw material sources are wide, cheap, obtain added value manganese carbonate and ammonium sulfate product higher, remarkable in economical benefits, overcome simultaneously ammonium bisulfite prepare ammonium sulfate there is a problem of that oxidation efficiency is low and manganese carbonate preparation process to there is production cost high, and the technological operation is simple, process conditions are gentle, reaction can be completed at ambient temperature, and the product quality of acquisition is high, meets industrialization production requirements.

Description

A kind of resource ammonia desulfurizing process

Technical field

Sulfur dioxide FGD is carried out by desulfurizing agent of ammonium hydrogen carbonate the present invention relates to one kind, the product for obtaining is used for also Former pyrolusite is while the technique of co-producing manganese carbonate and ammonium sulfate, belongs to flue gas desulfurization technique field.

Background technology

Wet Flue Gas Desulfurization Technique mainly includes, limestone-based process, Dual alkali, ammonia process etc..Ammonia desulfurizing process is a kind of green work Skill, can with liquefied ammonia, ammoniacal liquor, ammonium hydrogen carbonate etc. as desulfurizing agent, the method have desulfuration efficiency it is high, without blocking, accessory substance sulfuric acid Ammonium can as chemical fertilizer products the advantages of；But liquefied ammonia, ammoniacal liquor, ammonium hydrogen carbonate etc. are used as desulfurizing agent, the dioxy in making it with flue gas Changing reaction of Salmon-Saxl, and blast air makes sulfite oxidation for ammonium sulfate, because ammonium sulfite forces oxidation effectiveness poor, generation Ammonium sulfate product quality is not high.Therefore exploitation can solve the problem that the ammonia desulfurizing process of sulfite oxidation problem, will be with very Good market prospects.

China's pyrolusite resource is relatively enriched, but grade is relatively low.Pyrolusite main component containing manganese is MnO₂, sulfuric acid can not be It is directly leached, it is necessary to which it is reduced into manganese monoxide (MnO) could generate manganese sulfate with sulfuric acid reaction, and the manganese sulfate of generation exists Metathesis reaction is further carried out with carbonate manganese carbonate is obtained.The method need to consume substantial amounts of reducing agent and sulfuric acid, be produced into This is higher, and resource utilization degree is not high.For example, Publication No. CN103553078A Chinese invention patents disclose a kind of efficient Ammonia process of desulfurization crystallization prepares the technique of ammonium sulfate, and the technique includes desulfurization, oxidation, enrichment process, is first passed through flue gas, ammoniacal liquor Desulfurizing tower desulfurization section, the slurries containing ammonium bisulfite and ammonium sulfite generated after reaction desulfuration enter regeneration storage tank；By ammonia Water is passed through regeneration storage tank and ammonium bisulfite reaction generation ammonium sulfite, then ammonium sulfite solution is passed through into desulfurizing tower oxidation panel, The slurries containing ammonium sulfate with smoke reaction oxidation generation enter concentration storage tank；Ammonium sulfate after crystallisation by cooling, solid-liquid Separate and ammonium sulfate product is obtained.The technique has sulfite oxidation efficiency high, and effectively reduces equipment investment and energy consumption The characteristics of.But the method has the escaping of ammonia, the problems such as the sulfite oxidation time is long.

The Chinese patent of Publication No. 101704553A discloses a kind of preparation method of manganese carbonate, starches MnSO₄Add H₂SO₄, regulation pH value is 2~4；In 30~80 DEG C of temperature ranges, stirring is lower to add ammonium hydrogen carbonate to be synthesized, control synthesis Terminal is reaction with same mole, obtains Synthesis liquid；Then above-mentioned Synthesis liquid separation of solid and liquid, solid phase are dried with 80~100 DEG C of hot washes Do to obtain manganese carbonate.The invention can obtain the manganese carbonate of the low magnesium of low calcium, but manganese sulfate is used as a kind of industrial chemicals, expensive, It is poor manganese carbonate economy to be produced with manganese sulfate.

The content of the invention

It is low and manganese carbonate to there is oxidation efficiency in the technique for preparing ammonium sulfate for the ammonia process of desulfurization traditional in the prior art Production there are problems that, be obtained as fume desulfurizing agent by the use of ammonium hydrogen carbonate it is an object of the invention to provide a kind of Desulfurization product, then desulfurization product reducing pyrolusite is dexterously utilized, while obtaining the manganese carbonate and ammonium sulfate product of high-purity Technique, the technological operation is simple, and reaction condition is gentle, and cost of material is low, the manganese carbonate and ammonium sulfate product added value of acquisition compared with Height, meets industrialized production.

The invention provides a kind of resource ammonia desulfurizing process, the technique is comprised the following steps：

Step one：Flue gas desulfurization

Using the solution containing ammonium hydrogen carbonate as absorbing liquid, reacted with the smoke contacts containing sulfur dioxide in absorption tower, obtained It is liquid after the absorption of ammonium bisulfite to main component；

Step 2：Oxidation regeneration

Step one gained absorb after liquid enter oxidation regeneration reactor in, regulation absorb after liquid pH 4.5~5.5 it Between, then addition pyrolusite carries out redox reaction in oxidation regeneration reactor, after the completion of reaction, is separated by filtration, and separates To the filtrate and solid phase slag of sulfur acid manganese and ammonium sulfite；

Step 3：Production MnCO₃

Into after being settled in sedimentation basin, liquid enters in precipitation reactor step 2 gained filtrate after part settles, control 6.8~7.2, be passed through oxygen and addition ammonium hydrogen carbonate carries out oxidation precipitation reaction to solution ph, reacts in precipitation reactor processed After the completion of, it is separated by filtration, isolated manganese carbonate solid and ammonium sulfate；

Step 4：Production (NH₄)SO₄

Step 3 gained ammonium sulfate obtains ammonium sulfate product by evaporative crystallization.

Ammonia process of desulfurization product based on ammonium hydrogen carbonate of the invention is used for reducing pyrolusite and co-producing manganese carbonate and ammonium sulfate Technique also includes following preferred scheme：

Absorbing liquid also includes ammonium sulfate and ammonium bisulfite composition, the quality of ammonium hydrogen carbonate in absorbing liquid in preferred scheme Percent concentration is that 15~30%, pH is 4.5~5.5.

The flow velocity that the flue gas containing sulfur dioxide passes through absorption tower in step one in preferred scheme is 3~6m/s, liquid-gas ratio In 5~18L/m³Between.

More preferably absorption tower is spray column, packed tower or sieve-plate tower in scheme.

1~3h of time that redox reaction is carried out in preferred scheme.

Pyrolusite granularity is not less than 200 mesh in preferred scheme, and manganese content is not less than 20%.

The solid phase slag of gained is used to prepare cement in step 2 in preferred scheme.

The mud of settling tank bottom reacts in returning to oxidation regeneration reactor in step 3 in preferred scheme.

1~4h of time that oxidation precipitation reaction is carried out in preferred scheme.

Liquid adjusts pH by the flue gas containing sulfur dioxide after being absorbed in step 2 in preferred scheme.

Adjusted by the sulfuric acid solution that mass percent concentration is 5~10% in step 3 in preferred scheme and maintain sedimentation The pH value of liquid is 6.8~7.2 afterwards.

Liquid enters and is used as absorbing liquid regulation component return absorption tower after partly being settled in step 3 in preferred scheme.

A kind of resource ammonia desulfurizing process of the invention specifically includes following steps：

Step one：Flue gas desulfurization

By ammonium hydrogen carbonate by water (or washing manganese carbonate product cleaning solution, or precipitation after liquid) be configured to carbon Absorbing liquid of the sour hydrogen ammonium mass percent concentration 15~30%, the pH of absorbing liquid is controlled 4.5~5.5, and absorbing liquid is defeated through pump Absorption tower is fed into inversely to be contacted with containing the flue gas of sulfur dioxide, the flue gas containing sulfur dioxide by the flow velocity on absorption tower for 3~ 6m/s, liquid-gas ratio is in 5~18L/m³Between, ammonium hydrogen carbonate and SO₂Ammonium bisulfite is reacted and generated, main component is obtained It is NH₄HSO₃Absorption after liquid, the key reaction equation of generation is as follows：

NH₄HCO₃+SO₂→NH₄HSO₃+CO₂；

Step 2：Oxidation regeneration

Liquid is delivered to oxidation regeneration reactor after absorption, and blasting liquid pH after a small amount of flue gas adjusts absorption by air blower exists Between 4.5~5.5, pyrolusite is added to carry out redox reaction, preferred pyrolusite granularity is not less than 200 mesh, and manganese content is not Less than 20%, ammonium bisulfite is by MnO in pyrolusite₂Oxidation, after absorption liquid in oxidation regeneration reactor the residence time 1~ The mixed solution of 3h, generation manganese sulfate and ammonium sulfite, is isolated by filtration out the solid slag for having neither part nor lot in reaction, and solid slag is used for Production cement, the key reaction equation occurred in course of reaction is as follows：

MnO₂+2NH₄HSO₃→MnSO₄+(NH₄)₂SO₃+H₂O；

Step 3：Production MnCO₃

The filtrate for being separated by filtration gained sulfur acid manganese and ammonium sulfite enters in sedimentation basin, and sedimentation basin bottom mud returns to oxygen Change regeneration reactor；The absorption tower of liquid return to step one recycles after partly precipitated, and liquid enters precipitation reaction after partly precipitated Device, liquid pH value is passed through 1~4h of oxygen reaction, manganese sulfate and carbonic acid between 6.8~7.2 after adding a small amount of sulfuric acid control precipitation Hydrogen ammonium and oxygen reaction generation manganese carbonate precipitation and ammonium sulfate, are separated by filtration, and wash, and dry, and obtain manganese carbonate product；Reaction During occur key reaction equation it is as follows：

2NH₄HCO₃+MnSO₄+(NH₄)₂SO₃+O₂→MnCO₃+2(NH₄)SO₄+H₂O+CO₂

Step 4：Production (NH₄)₂SO₄

Be separated by filtration in step 3 gained filtrate through evaporative crystallization, be separated by filtration, dry after obtain final product ammonium sulfate product；Evaporation Crystallize the steam for producing to mix with clear water directly contact into cooling tower, warm water of the generation temperature at 60~70 DEG C, and for washing Wash manganese carbonate.

Compared with the prior art, the beneficial effect that the present invention brings：The present invention first by sulfur dioxide FGD technique and The preparation technology of manganese carbonate is ideally combined, with sulfur dioxide flue gas, ammonium hydrogen carbonate and pyrolusite as raw material, while completing dioxy Change absorption oxidation and the pyrolusite reduction and carbonization of sulphur, obtain surcharge manganese carbonate and ammonium sulfate product higher.Present invention choosing Ammonium hydrogen carbonate is selected as desulfuration reagent, ammonium hydrogen carbonate not only has the effect of preferable sulfur dioxide absorption, and ammonium hydrogen carbonate The midbody product that sulfur dioxide absorption is produced has suitable reducing property；On this basis, the present invention further selects honest and clean The pyrolusite of valency is raw material, makes full use of the oxidation susceptibility in the reducing property and pyrolusite of desulfurization product to combine two kinds of techniques Get up, have that oxidation efficiency is low and manganese carbonate preparation process has production cost while overcoming ammonium bisulfite and preparing ammonium sulfate Problem high, obtains manganese carbonate and ammonium sulfate product respectively.The sulfur dioxide flue gas of selection of the invention, ammonium hydrogen carbonate and soft manganese Ore deposit raw material sources are wide, cheap, obtain added value manganese carbonate and ammonium sulfate product higher, remarkable in economical benefits.Work of the invention Skill is simple to operate, process conditions are gentle, and reaction is completed by being substantially all at room temperature, and acquisition product quality is high, meets industry Change production requirement.

Brief description of the drawings

【Fig. 1】It is process chart of the invention.

Specific embodiment

Following examples are intended to further illustrate present invention, rather than the protection model of limitation the claims in the present invention Enclose.

Embodiment 1

A, desulfurization：Ammonium hydrogen carbonate is configured to ammonium bicarbonate concentration and exists with part of sulfuric acid ammonium salt solution, certain proportion process water 20% ammonium bicarbonate soln, inversely contacts, SO into ammonium absorption tower through the input of slurries pump with flue gas₂Concentration is 2100mg/Nm³'s The flow velocity that flue gas passes through absorption tower is 5m/s, liquid-gas ratio 10L/m in tower³, the SO in ammonium hydrogen carbonate and flue gas₂React and give birth to Into ammonium bisulfite.After desulfurization, SO₂Removal efficiency is 97%, SO in neat stress₂Concentration is 65mg/Nm³。

B, oxidation regeneration：Slurries after desulfurization are delivered to oxidation regeneration reactor, ammonium bisulfite therein is by soft manganese MnO in ore deposit (manganese content 25%, 220 mesh)₂Oxidation regeneration, air blower blasts a small amount of flue gas and adjusts slurries pH between 5~6, Slurries residence time 60min.

C、MnCO₃Production：By the slurries filtering after above-mentioned oxidation regeneration, solid phase slag is used to produce cement, and filtrate enters In sedimentation basin, sedimentation basin bottom mud returns to band filter filtering, and partly staticly settling rear filtrate and returning ammonia absorber and circulate makes Enter precipitation reactor with, portion filtrate, add a small amount of sulfuric acid to control solution ph 7.0, manganese sulfate therein and bicarbonate Ammonium and oxygen reaction 2h or so generation manganese carbonate precipitation and ammonium sulfate, manganese carbonate product purity is 98.5%.By precipitation reaction Slurries filtering afterwards, separation of solid and liquid obtains manganese carbonate product after the scrubbed drying of solid phase.Filtrate stores into filtrate tank.

D、(NH₄)SO₄Production：In above-mentioned filtrate tank clear liquid through evaporative crystallization, be separated by filtration, dry after ammonium sulfate product. The steam that evaporative crystallization is produced mixes into cooling tower with clear water directly contact, the warm water of 70 DEG C of generation, and for washing carbonic acid Manganese.Ammonium sulfate product purity is 98.6%.

Embodiment 2

A, desulfurization：Ammonium hydrogen carbonate is configured to ammonium bicarbonate concentration and exists with part of sulfuric acid ammonium salt solution, certain proportion process water 26% ammonium bicarbonate soln, inversely contacts, SO into ammonium absorption tower through the input of slurries pump with flue gas₂Concentration is 2400mg/Nm³'s The flow velocity that flue gas passes through absorption tower is 3.4m/s, liquid-gas ratio 10L/m in tower³, the SO in ammonium hydrogen carbonate and flue gas₂React simultaneously Generation ammonium bisulfite.After desulfurization, SO₂Removal efficiency is 97%, SO in neat stress₂Concentration is 72mg/Nm³。

B, oxidation regeneration：Slurries after desulfurization are delivered to oxidation regeneration reactor, ammonium bisulfite therein is by soft manganese MnO in ore deposit (manganese content 30%, 220 mesh)₂Oxidation regeneration, air blower blasts a small amount of flue gas and adjusts slurries pH between 5~6, Slurries residence time 120min.

C、MnCO₃Production：By the slurries filtering after above-mentioned oxidation regeneration, solid phase slag is used to produce cement, and filtrate enters In sedimentation basin, sedimentation basin bottom mud returns to band filter filtering, and partly staticly settling rear filtrate and returning ammonia absorber and circulate makes Enter precipitation reactor with, portion filtrate, add a small amount of sulfuric acid to control solution ph 7.0, manganese sulfate therein and bicarbonate Ammonium and oxygen reaction 2h or so generation manganese carbonate precipitation and ammonium sulfate, manganese carbonate product purity is 98.1%.By precipitation reaction Slurries filtering afterwards, separation of solid and liquid obtains manganese carbonate product after the scrubbed drying of solid phase.Filtrate stores into filtrate tank.

D、(NH₄)SO₄Production：In above-mentioned filtrate tank clear liquid through evaporative crystallization, be separated by filtration, dry after ammonium sulfate product. The steam that evaporative crystallization is produced mixes into cooling tower with clear water directly contact, the warm water of 70 DEG C of generation, and for washing carbonic acid Manganese.Ammonium sulfate product purity is 98.8%.

Embodiment 3

A, desulfurization：Liquid and certain proportion process water are configured to bicarbonate after precipitation in ammonium hydrogen carbonate and the step C of embodiment 2 Ammonium concentration is inversely contacted, SO into ammonium absorption tower through the input of slurries pump in 18% ammonium bicarbonate soln with flue gas₂Concentration is 2000mg/Nm³Flue gas be 5m/s, liquid-gas ratio 10L/m in tower by the flow velocity on absorption tower³, the SO in ammonium hydrogen carbonate and flue gas₂ React and generate ammonium bisulfite.After desulfurization, SO₂Removal efficiency is 97%, SO in neat stress₂Concentration is 60mg/Nm³。

B, oxidation regeneration：Slurries after desulfurization are delivered to oxidation regeneration reactor, ammonium bisulfite therein is by soft manganese MnO in ore deposit (manganese content 30%, 220 mesh)₂Oxidation regeneration, air blower blasts a small amount of flue gas and adjusts slurries pH between 5~6, Slurries residence time 70min.

C、MnCO₃Production：By the slurries filtering after above-mentioned oxidation regeneration, solid phase slag is used to produce cement, and filtrate enters In sedimentation basin, sedimentation basin bottom mud returns to band filter filtering, and partly staticly settling rear filtrate and returning ammonia absorber and circulate makes Enter precipitation reactor with, portion filtrate, add a small amount of sulfuric acid to control solution ph 7.0, manganese sulfate therein and bicarbonate Ammonium and oxygen reaction 2h or so generation manganese carbonate precipitation and ammonium sulfate, manganese carbonate product purity is 98.0%.By precipitation reaction Slurries filtering afterwards, separation of solid and liquid obtains manganese carbonate product after the scrubbed drying of solid phase.Filtrate stores into filtrate tank.

D、(NH₄)SO₄Production：In above-mentioned filtrate tank clear liquid through evaporative crystallization, be separated by filtration, dry after ammonium sulfate product. The steam that evaporative crystallization is produced mixes into cooling tower with clear water directly contact, the warm water of 70 DEG C of generation, and for washing carbonic acid Manganese.Ammonium sulfate product purity is 98.0%.

Claims (8)

1. a kind of resource ammonia desulfurizing process, it is characterised in that comprise the following steps：

Step one：Flue gas desulfurization

Using the solution containing ammonium hydrogen carbonate as absorbing liquid, reacted with the smoke contacts containing sulfur dioxide in absorption tower, led Want liquid after the absorption that composition is ammonium bisulfite；Described absorbing liquid also includes ammonium sulfate and ammonium bisulfite composition, absorbing liquid The mass percent concentration of middle ammonium hydrogen carbonate is that 15~30%, pH is 4.5~5.5；

Step 2：Oxidation regeneration

Liquid enters in oxidation regeneration reactor after step one gained absorbs, and adjusts the pH of liquid after absorbing between 4.5~5.5, then Pyrolusite is added in oxidation regeneration reactor carries out redox reaction, after the completion of reaction, is separated by filtration, isolated sulfur-bearing The filtrate and solid phase slag of sour manganese and ammonium sulfite；

Step 3：Production MnCO₃

Into after being settled in sedimentation basin, liquid enters and is returned as absorbing liquid regulation component step 2 gained filtrate after part settles Return absorption tower use, part settle after liquid enter precipitation reactor in, control precipitation reactor in solution ph 6.8~7.2, Being passed through oxygen and addition ammonium hydrogen carbonate carries out oxidation precipitation reaction, after the completion of reaction, is separated by filtration, isolated manganese carbonate solid And ammonium sulfate；

Step 4：Production (NH₄)₂SO₄

Step 3 gained ammonium sulfate obtains ammonium sulfate product by evaporative crystallization.

2. technique according to claim 1, it is characterised in that the flow velocity that the flue gas containing sulfur dioxide passes through absorption tower is 3 ~6m/s, liquid-gas ratio is in 5~18L/m³Between.

3. technique according to claim 1 and 2, it is characterised in that described absorption tower is spray column, packed tower or sieve plate Tower.

4. technique according to claim 1, it is characterised in that 1~3h of time that described redox reaction is carried out.

5. technique according to claim 1, it is characterised in that described pyrolusite granularity is not less than 200 mesh, and manganese content is not Less than 20%.

6. technique according to claim 1, it is characterised in that the solid phase slag of gained is used to prepare cement in step 2； The mud of settling tank bottom reacts in returning to oxidation regeneration reactor in step 3.

7. technique according to claim 1, it is characterised in that 1~4h of time that described oxidation precipitation reaction is carried out.

8. technique according to claim 1, it is characterised in that liquid is by the flue gas containing sulfur dioxide after being absorbed in step 2 Regulation pH；In step 3 after sulfuric acid solution that mass percent concentration is 5~10% adjusts sedimentation the pH value of liquid 6.8~ 7.2。