CN116750984B - Byproduct gypsum treatment method and system for co-production of cement clinker by sulfuric acid production - Google Patents
Byproduct gypsum treatment method and system for co-production of cement clinker by sulfuric acid production Download PDFInfo
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- CN116750984B CN116750984B CN202310741341.3A CN202310741341A CN116750984B CN 116750984 B CN116750984 B CN 116750984B CN 202310741341 A CN202310741341 A CN 202310741341A CN 116750984 B CN116750984 B CN 116750984B
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- 239000010440 gypsum Substances 0.000 title claims abstract description 165
- 229910052602 gypsum Inorganic materials 0.000 title claims abstract description 165
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 56
- 239000006227 byproduct Substances 0.000 title claims abstract description 44
- 239000004568 cement Substances 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 29
- 239000000843 powder Substances 0.000 claims abstract description 133
- 239000000463 material Substances 0.000 claims abstract description 83
- 239000007787 solid Substances 0.000 claims abstract description 62
- 238000000926 separation method Methods 0.000 claims abstract description 54
- 239000013067 intermediate product Substances 0.000 claims abstract description 39
- 239000003054 catalyst Substances 0.000 claims abstract description 35
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 31
- 239000000292 calcium oxide Substances 0.000 claims abstract description 31
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 30
- 238000002156 mixing Methods 0.000 claims abstract description 30
- 239000007790 solid phase Substances 0.000 claims abstract description 22
- 230000001590 oxidative effect Effects 0.000 claims abstract description 7
- 239000007789 gas Substances 0.000 claims description 85
- 238000000354 decomposition reaction Methods 0.000 claims description 47
- 238000007254 oxidation reaction Methods 0.000 claims description 37
- 230000003647 oxidation Effects 0.000 claims description 36
- 230000009467 reduction Effects 0.000 claims description 32
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 29
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 22
- 238000002485 combustion reaction Methods 0.000 claims description 20
- 238000002360 preparation method Methods 0.000 claims description 19
- 229910052717 sulfur Inorganic materials 0.000 claims description 19
- 239000011593 sulfur Substances 0.000 claims description 19
- 239000003546 flue gas Substances 0.000 claims description 15
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 14
- 229910044991 metal oxide Inorganic materials 0.000 claims description 14
- 150000004706 metal oxides Chemical class 0.000 claims description 14
- 239000000446 fuel Substances 0.000 claims description 11
- 238000003860 storage Methods 0.000 claims description 11
- 239000000725 suspension Substances 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 10
- 229910052760 oxygen Inorganic materials 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 229910001422 barium ion Inorganic materials 0.000 claims description 7
- 238000009826 distribution Methods 0.000 claims description 7
- 150000002500 ions Chemical class 0.000 claims description 7
- 239000002817 coal dust Substances 0.000 claims description 5
- 238000001354 calcination Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 2
- 230000000712 assembly Effects 0.000 claims 1
- 238000000429 assembly Methods 0.000 claims 1
- 239000000543 intermediate Substances 0.000 abstract description 3
- 235000012255 calcium oxide Nutrition 0.000 description 23
- 239000003245 coal Substances 0.000 description 23
- 230000008569 process Effects 0.000 description 12
- 230000009471 action Effects 0.000 description 11
- 239000000428 dust Substances 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 239000002994 raw material Substances 0.000 description 10
- 230000000630 rising effect Effects 0.000 description 10
- 238000005303 weighing Methods 0.000 description 8
- 238000013461 design Methods 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 238000006477 desulfuration reaction Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- JGIATAMCQXIDNZ-UHFFFAOYSA-N calcium sulfide Chemical compound [Ca]=S JGIATAMCQXIDNZ-UHFFFAOYSA-N 0.000 description 5
- 230000023556 desulfurization Effects 0.000 description 5
- 239000004744 fabric Substances 0.000 description 5
- 238000000265 homogenisation Methods 0.000 description 5
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 239000002912 waste gas Substances 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 230000001174 ascending effect Effects 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000010881 fly ash Substances 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 244000261422 Lysimachia clethroides Species 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 230000003009 desulfurizing effect Effects 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000005496 eutectics Effects 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- AGVJBLHVMNHENQ-UHFFFAOYSA-N Calcium sulfide Chemical class [S-2].[Ca+2] AGVJBLHVMNHENQ-UHFFFAOYSA-N 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- -1 baO) having Ba ions Chemical class 0.000 description 1
- 229910001570 bauxite Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 235000011180 diphosphates Nutrition 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 238000003837 high-temperature calcination Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000008247 solid mixture Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B11/00—Calcium sulfate cements
- C04B11/26—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke
- C04B11/266—Chemical gypsum
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/48—Sulfur dioxide; Sulfurous acid
- C01B17/50—Preparation of sulfur dioxide
- C01B17/501—Preparation of sulfur dioxide by reduction of sulfur compounds
- C01B17/506—Preparation of sulfur dioxide by reduction of sulfur compounds of calcium sulfates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B11/00—Calcium sulfate cements
- C04B11/02—Methods and apparatus for dehydrating gypsum
- C04B11/028—Devices therefor characterised by the type of calcining devices used therefor or by the type of hemihydrate obtained
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B11/00—Calcium sulfate cements
- C04B11/02—Methods and apparatus for dehydrating gypsum
- C04B11/028—Devices therefor characterised by the type of calcining devices used therefor or by the type of hemihydrate obtained
- C04B11/036—Devices therefor characterised by the type of calcining devices used therefor or by the type of hemihydrate obtained for the dry process, e.g. dehydrating in a fluidised bed or in a rotary kiln, i.e. to obtain beta-hemihydrate
Abstract
The invention discloses a method and a system for treating byproduct gypsum of co-production cement clinker by sulfuric acid production, wherein the treatment method comprises the following steps: (1) pretreating byproduct gypsum; (2) preparing auxiliary materials and a catalyst; (3) respectively preheating the gypsum powder and the auxiliary materials; (4) Reducing and decomposing gypsum powder in a decomposing furnace to obtain SO 2 Gas and solid intermediates; (5) For SO 2 Gas and solid separation is carried out on the gas and solid intermediate products, and the separated solid intermediate products are subjected to secondary material separation, part of the solid intermediate products are sent to the rear end of the decomposing furnace, and the rest of the solid intermediate products are returned to the front end of the decomposing furnace; (6) SO at the rear end of the decomposing furnace 2 The solid-phase calcium oxide and SO are obtained by gas and partial solid intermediate products under the conditions of weak oxidizing atmosphere and not more than 1100 DEG C 2 A gas; (7) Solid phase calcium oxide, SO 2 Mixing the gas with the auxiliary materials, performing gas-solid separation, and delivering the solid-phase calcium oxide and the auxiliary materials to a rotary kiln system SO 2 The gas is sent to a sulfuric acid making system. The invention greatly improves the sulfuric acid concentration and the quality of cement clinker.
Description
Technical Field
The invention relates to the technical field of co-production of cement clinker by industrial gypsum sulfuric acid production, in particular to a byproduct gypsum treatment method and system for co-production of cement clinker by sulfuric acid production.
Background
Sulfuric acid is an important industrial raw material, can be used for manufacturing products such as fertilizers, medicines, explosives, pigments, detergents, storage batteries and the like, and is widely used for purifying industries such as petroleum, metal smelting, dyes and the like, and the dosage is huge; cement is a bulk basic raw material, and has wide application and large dosage, so that both products have very good sales. At present, the co-production of sulfuric acid and cement clinker by using industrial by-product gypsum is a main stream mode of recycling industrial by-product gypsum resources and realizing energy conservation and environmental protection, and has the advantages of large treatment capacity of industrial by-product gypsum, capability of recycling produced sulfuric acid in enterprises, good market of cement clinker outside and the like. The successful application of the new technology for preparing sulfuric acid and co-producing cement clinker by using industrial by-product gypsum provides an effective way for large-scale and high-value treatment and utilization of industrial by-product gypsum, and has remarkable environmental protection, economy and social benefits.
Seven sets of 'forty-six' (4 ten thousand tons of sulfuric acid and 6 ten thousand tons of cement) engineering devices are built together in the middle and later stages of the 90 th century in China, and gypsum is used as a raw material. According to statistics, seven sets of devices can reach the production standard, normal production is achieved, the production technology is mature and reliable, and good social benefits and economic benefits are obtained, so that the four-six engineering is successful. However, there are still some problems in actual operation: (1) SO in kiln gas 2 The concentration is lower, and the volume concentration is generally only 7-9%; (2) the co-production cement has low grade, and the quality is not easy to be ensured; (3) The utilization rate of the rotary kiln is low, the unit clinker heat consumption is up to 10600KJ/kg, and the unit volume yield is low; (4) The thermal system of the rotary kiln is difficult to stabilize, because the decomposing zone requires micro-reduction atmosphere, the oxidizing zone requires micro-oxidation atmosphere, the adjusting difficulty is high, and the operation is not easy to control.
The inventors have devised corresponding solutions to some of the above problems, such as problems (1) to (3), patent publication No.: CN217636840U describes a cement clinker production system with double series of suspension preheaters, which improves the single series of preheaters into double series of preheaters, and respectively divides the kiln row and kiln row gases, SO as to reduce the exhaust gas quantity of the kiln row, thereby relatively improving SO in the flue gas of the kiln row 2 Is a concentration of (2); the pipeline type decomposing furnace is adopted, a kiln tail rising pipeline is lengthened to form a gooseneck, and a plurality of necking ports are arranged in the pipeline type decomposing furnace along the direction from the bottom end to the top end, so that materials and smoke can generate a 'spurting effect' in the decomposing furnace to increase heat exchange time, the decomposition of gypsum is ensured, and the quality of cement is further ensured; by improving the rotary kiln systemThe utilization rate of the rotary kiln is effectively improved.
Although the above solution solves some of the technical problems, it does not solve problem (4) at first, and the adjustment operation of the rotary kiln is still difficult to control; secondly, in practical application, SO in the flue gas 2 Limited increases in concentration up to only about 12.5%; thirdly, the decomposition temperature in the decomposing furnace is higher and reaches 1350-1450 ℃, so that the energy consumption is higher; fourth, raw materials added into the kiln line preheater and the kiln line preheater are a mixture of gypsum materials and auxiliary materials, and after the raw materials are preheated by the kiln line preheater and enter the decomposing furnace, liquid phase wrapping is easy to occur (namely melting phenomenon occurs) due to the high temperature of 1350-1450 ℃ and the existence of the auxiliary materials, so that the decomposing furnace is blocked, and the external decomposition of gypsum is influenced.
Therefore, there is a need for further improvements to this in order to more effectively address the deficiencies of the prior art solutions.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a byproduct gypsum treatment method and a byproduct gypsum treatment system for producing sulfuric acid and co-producing cement clinker.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for treating by-product gypsum for producing sulfuric acid and co-producing cement clinker comprises the following steps:
(1) Pretreating the byproduct gypsum to obtain gypsum powder, and storing the gypsum powder for later use;
(2) Preparing auxiliary materials and catalysts in the form of powder, and storing for later use;
(3) Preheating the gypsum powder by adopting a multi-stage furnace array preheater, so that the temperature of the gypsum powder reaches at least 750 ℃ when the gypsum powder comes out;
(4) Preheating the auxiliary materials by adopting a two-stage kiln array preheater, so that the temperature of the auxiliary materials reaches at least 520 ℃ when the auxiliary materials come out;
(5) Mixing the gypsum powder preheated in the step (3) with a catalyst, decomposing the gypsum powder in the front end of the inside of a decomposing furnace under the conditions of reducing atmosphere and 1000-1100 ℃ to obtain SO 2 The catalyst is used for reducing the decomposition critical temperature of gypsum powder;
(6) For SO 2 Gas-solid separation of gas from solid intermediate product, wherein the separated SO 2 The gas is all sent to the rear end of the decomposing furnace; the separated solid intermediate product is sent to the rear end and SO inside the decomposing furnace by secondary material separation 2 Mixing the gases, returning the rest solid intermediate products to the front end of the inside of the decomposing furnace, mixing the solid intermediate products with gypsum powder, and continuing to decompose in a reducing atmosphere;
(7) SO sent to the rear end of the decomposing furnace 2 The solid-phase calcium oxide and SO are obtained by gas and partial solid intermediate products under the conditions of weak oxidizing atmosphere and not more than 1100 DEG C 2 A gas;
(8) Solid phase calcium oxide and SO 2 Mixing the gas with the auxiliary materials preheated in the step (4), carrying out gas-solid separation, sending the solid-phase calcium oxide and the auxiliary materials into a rotary kiln system for calcining treatment, and finally obtaining cement clinker and SO 2 The gas is sent to a sulfuric acid making system.
Specifically, the catalyst comprises a metal oxide with Mn ions and a metal oxide with Ba ions, wherein the metal oxide with Mn ions accounts for 0.4-0.6% of the weight of the gypsum powder, and the metal oxide with Ba ions accounts for 1-2% of the weight of the gypsum powder.
Specifically, the reducing gas in the reducing atmosphere is mixed gas of sulfur steam and carbon monoxide.
Further, in the step (6), one third of the solid intermediate product is sent to the rear end of the interior of the decomposing furnace, and the remaining two thirds of the solid intermediate product is returned to the front end of the interior of the decomposing furnace.
Still further, the total residence time of the gypsum powder in the decomposing furnace is at least 60s.
In the step (3), a part of gypsum powder is split into a multi-stage kiln line preheater for preheating, and the preheated gypsum powder enters a decomposing furnace.
Based on the processing method, the invention also provides a corresponding processing system, which comprises the following steps:
the byproduct gypsum pretreatment system is used for crushing, drying and homogenizing byproduct gypsum to obtain gypsum powder and storing the gypsum powder;
the auxiliary material and catalyst preparation system is used for preparing auxiliary materials and catalysts in the form of powder materials and storing the auxiliary materials and the catalysts;
the multi-stage furnace array preheater is used for preheating gypsum powder;
the two-stage kiln array preheater is used for preheating auxiliary materials;
the decomposing furnace device is used for decomposing the preheated gypsum powder to obtain solid-phase calcium oxide and SO 2 A gas; the decomposing furnace device comprises a decomposing furnace front-end reduction decomposing section, a suspension separating cylinder, a decomposing furnace rear-end oxidation section and a distributor arranged on the suspension separating cylinder, which are sequentially connected, wherein a combustion area is arranged in the decomposing furnace front-end reduction decomposing section; the distributor is used for carrying out secondary distribution on the solid intermediate product and respectively delivering the solid intermediate product to a reduction decomposition section at the front end of the decomposing furnace and an oxidation section at the rear end of the decomposing furnace;
a mixing separation chamber for mixing solid-phase calcium oxide and SO 2 Gas and auxiliary materials are subjected to gas-solid separation; isolated SO 2 The gas is discharged through the kiln line preheater and simultaneously provides a heat source for the kiln line preheater;
the reducing gas preparation system is used for preparing sulfur steam and spraying the sulfur steam from a combustion zone in the decomposing furnace;
a calciner for providing a heat source to the multi-stage train preheater;
the rotary kiln system is used for providing kiln gas into the decomposing furnace device and processing the mixed material of the solid-phase calcium oxide and the auxiliary materials from the mixing separation chamber to obtain cement clinker; simultaneously, oxygen is also provided for the oxidation section at the rear end of the decomposing furnace.
Further, the distributor is respectively connected with the reduction decomposition section at the front end of the decomposing furnace and the oxidation section at the rear end of the decomposing furnace through a heat-insulating blanking pipe.
Still further, the invention also comprises a multi-stage kiln array preheater, wherein the air outlet of the multi-stage kiln array preheater is connected with the two-stage kiln array preheater, and the discharging outlet of the multi-stage kiln array preheater is connected with the reduction decomposition section at the front end of the decomposing furnace and is used for preheating gypsum powder; the air inlet of the multi-stage kiln array preheater is connected with the mixing separation chamber.
Still further, the invention also includes a coal dust preparation and storage system for providing fuel to the calciner and rotary kiln systems, and a low heating value gangue pre-combustion hot blast stove system for providing high temperature flue gas to the calciner and decomposing furnace units.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the invention, the catalyst is added in the process of decomposing the gypsum powder, the catalyst adopts the mixture of the metal oxide with Mn ions and the metal oxide with Ba ions, and experiments show that the use of the catalyst can effectively reduce the decomposition critical temperature of the gypsum powder, the decomposition temperature in the decomposing furnace only needs to ensure that the gypsum powder can be decomposed within the range of 1000-1100 ℃, so that the energy consumption of the decomposing furnace and even the whole system is greatly reduced, and the quality of cement clinker can be further improved by adding the catalyst component.
(2) The invention preheats the gypsum powder and auxiliary materials separately, the kiln line preheater only preheats the gypsum powder, then the gypsum powder is sent into the decomposing furnace for decomposition, the kiln line preheater preheats the auxiliary materials, and finally the auxiliary materials are mixed with the decomposed gypsum powder products, namely solid-phase calcium oxide and SO 2 The gases are mixed in a mixing separation chamber. Due to solid-phase calcium oxide and SO coming out of the decomposing furnace 2 The temperature of the gas-solid mixture of the gas is about 1100 ℃, so that under the action of instant heat transfer, the auxiliary materials can be instantly heated to over 1050 ℃ in the mixing and separating chamber, and the temperature of the mixed materials entering the rotary kiln system is ensured. Compared with the patent document CN217636840U, the invention eliminates the existence of auxiliary materials because the decomposing furnace only decomposes gypsum powder, and the decomposing temperature only needs 1000-1100 ℃ after the catalyst is added, thereby well avoiding the situation of blockage of the decomposing furnace caused by liquid phase encapsulation.
Moreover, since high-temperature calcination is the most effective method for removing impurities such as eutectic phosphorus in gypsum, in the present invention, the decomposing furnace has a high temperature of 1000-1100 ℃ and gypsum powderThe liquid phase is not wrapped in the decomposing furnace in a highly dispersed state. Thus, the eutectic phosphorus in gypsum can be converted to inert pyrophosphates after calcination at 800 ℃; soluble fluorine is converted into gas to volatilize, and the soluble phosphorus is decomposed into gas at 200-400 ℃ to be discharged or is partially converted into inert and stable phosphate. In this way, the invention can eliminate P to the maximum extent in the environment of decomposition outside the kiln 2 O 5 The influence on the strength of the cement clinker can further improve the quality of the cement clinker which is produced in the follow-up process.
(3) On the basis of the multi-stage kiln line preheater and the multi-stage kiln line preheater designed in the patent document CN217636840U, in order to effectively control the temperature of the outlet of the kiln line preheater, part of gypsum powder is shunted into the kiln line preheater for preheating (the phenomenon that the outlet temperature of the kiln line preheater is reduced due to large gypsum powder quantity and strong heat absorption effect in the kiln line preheater) and then enters a decomposing furnace for decomposition is avoided, so that the temperature of the gypsum powder entering the decomposing furnace can be ensured to reach the standard, the treatment capacity of the gypsum powder is improved, the heat of the kiln line preheater is fully utilized, the balance of the gypsum powder preheating treatment and the heat energy saving is realized, and the method can be used for achieving two purposes.
(4) The invention relates to a decomposing furnace device, which comprises a decomposing furnace front-end reduction decomposing section, a suspension separating cylinder, a distributor and a decomposing furnace rear-end oxidation section, wherein in the decomposing furnace front-end reduction decomposing section, the invention uses the mixed gas of carbon monoxide and sulfur steam as reducing gas, provides reducing atmosphere, and the following reaction occurs after gypsum powder enters the decomposing furnace front-end reduction decomposing section: caSO (Caso-like conductor) 4 +2CO→CaO+CO 2 ↑+SO 2 ↑、2CaSO 4 +S→2CaO+3SO 2 And ∈10, realizing the efficient decomposition of gypsum powder. Since the gypsum powder is decomposed for the first time and then subjected to gas-solid Separation (SO) under the action of the suspension separating cylinder 2 Gas and solid intermediate products are separated), and most of the solid intermediate products continuously return to the reduction decomposition section at the front end of the decomposing furnace under the secondary material separation effect of the distributor to continuously decompose SO 2 Gas (solid intermediates mainly comprising a small partIn the front-end reduction decomposition section of the decomposing furnace, these calcium sulfides and most of the calcium oxides will react as follows: 3CaSO 4 +CaS→4CaO+4SO 2 ∈, i.e. decomposing to obtain calcium oxide and SO 2 Gas), SO that the SO in the flue gas can be fully improved by the cyclic decomposition of the gypsum powder and the combination of reducing gas, especially sulfur steam 2 Is a concentration of (3). Experiments show that the invention adopts carbon monoxide and sulfur steam as reducing gas, and the SO is obtained by skillfully combining gypsum powder and sulfur steam 2 The concentration can reach 28.64% at most, which is far higher than the prior art, and the subsequent sulfuric acid preparation concentration is better ensured.
(5) The invention relates to a decomposing furnace back end oxidation section, which is provided with an oxygen inlet, kiln tertiary air on a rotary kiln system enters the decomposing furnace back end oxidation section through the oxygen inlet to form weak oxidizing atmosphere, and carbon monoxide entering the decomposing furnace back end oxidation section can be completely combusted after oxygen is provided in the decomposing furnace back end oxidation section to release heat, SO that the temperature in the decomposing furnace back end oxidation section reaches or is maintained at about 1100 ℃, and solid intermediate products sent by a distributor are basically completely converted into solid calcium oxide in the decomposing furnace back end oxidation section (the solid intermediate products mainly comprise a small part of calcium sulfide and a large part of calcium oxide, and are basically decomposed into calcium oxide and SO under the conditions of weak oxidizing atmosphere and high temperature of 1100℃) 2 Gas).
In addition, the invention returns two thirds of solid intermediate products to the front end reduction decomposition section of the decomposing furnace, and one third of the solid intermediate products enter the rear end oxidation section of the decomposing furnace, SO that the SO can be improved 2 Besides the concentration of the calcium sulfide in the solid intermediate product, the gas-solid ratio of the reduction decomposition section at the front end of the decomposing furnace and the gas-solid ratio of the oxidation section at the rear end of the decomposing furnace are always in the optimal state, so that the conversion of the calcium sulfide in the solid intermediate product into the calcium oxide is facilitated, and the secondary generation of the calcium sulfate is inhibited; meanwhile, the returning charge is continuously reduced and decomposed, so that the decomposition time of the gypsum powder in the decomposing furnace is further prolonged. Thus, the overall decomposition rate and desulfurization of the gypsum powder can be fully improvedThe rate.
Experiments show that in the invention, when the temperature of the front end reduction decomposition section of the decomposing furnace is 1000 ℃ and the temperature of the rear end oxidation section of the decomposing furnace is 1100 ℃, the reducing gas is carbon monoxide and sulfur steam, and the concentration of carbon monoxide is 5 percent, and the concentration of PCO/PCO is 5 percent 2 When the retention time of the gypsum powder in the decomposing furnace is 60s, the decomposing rate can reach 96.5% and the desulfurizing rate reaches 95.3%; when the retention time of the gypsum powder in the decomposing furnace is 120s, the decomposing rate can reach 99.6 percent, and the desulfurizing rate reaches 97.8 percent, thereby basically realizing the complete decomposition and desulfurization of the gypsum powder.
In summary, compared with the decomposing furnace with the 'gooseneck' structural design adopted in the patent document CN217636840U, the invention thoroughly solves the problem (4) existing in the prior art by further designing the shape, the structure and the temperature and atmosphere partition of the decomposing furnace, and realizes the stable adjustment and control of the thermal system of the rotary kiln.
(6) The invention also provides a low-heat-value coal gangue pre-combustion hot blast furnace system, the hot blast furnace system can obtain the low-heat-value coal gangue, the low-heat-value coal gangue can be used as raw materials of a coal powder preparation and storage system to be stored, the fuel cost of enterprises is reduced, and meanwhile, hot flue gas generated by combustion of the low-heat-value coal gangue can enter a furnace array preheater and a decomposing furnace to be utilized, so that the cyclic utilization of heat is further realized. The slag discharged by the hot blast stove system is dry, and can be used by self or sold to cement enterprises as a mixed material.
In addition, if a small amount of low-heat-value coal is added into the hot blast stove system, carbon monoxide gas can be generated, so that the hot blast stove system can be used for reducing gypsum powder and has a denitration effect. In addition, as the fly ash is discharged out of the hot blast stove system, the dust removal efficiency of the cyclone separator can reach 95%, the mixing amount of the fly ash can be greatly reduced, and the blockage of the decomposing furnace caused by the influence of the fly ash is further avoided.
(7) The invention has the advantages that all links are mutually buckled and complemented, and the overall application effect of the system is greatly improved, so that the invention fully plays the advantages of co-production of sulfuric acid and cement clinker by industrial byproduct gypsum, better responds to the policies of energy conservation and environmental protection, and is very suitable for large-scale popularization and application.
Drawings
FIG. 1 is a process flow diagram of an embodiment of the present invention.
FIG. 2 is a schematic diagram of a pretreatment system for gypsum byproduct in accordance with an embodiment of the invention.
Fig. 3 is a schematic structural diagram of an auxiliary material and catalyst preparation system in an embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a part of the system in the embodiment of the present invention.
FIG. 5 is a schematic diagram of the trend of gypsum powder and hot gases in a multi-stage kiln array preheater.
Fig. 6 is a schematic diagram of the trend of gypsum powder, auxiliary materials and high temperature gas in the multi-stage kiln array preheater.
FIG. 7 is a schematic drawing showing the direction of gypsum powder in a decomposing furnace apparatus.
Wherein, the spare part names that the reference numerals correspond are:
1-weighing bin, 2-belt scale, 3-feeder, 4-hammer type drying crusher, 5-fine powder separator, 6-cloth bag dust remover, 7-byproduct gypsum homogenizing bin, 8-desulfurization and denitrification system, 9-weighing steady flow bin, 10-roll squeezer, 11-V type powder concentrator, 12-dynamic powder concentrator, 13-cyclone separator, 14-circulating fan, 15-big cloth bag dust remover, 16-accessory homogenizing bin, 17-catalyst homogenizing bin, 18-exhaust fan, 19-byproduct gypsum desulfurization and denitrification system, 20-reducing gas preparation system, 21-decomposing furnace front end reduction decomposition section, 22-suspension separating cylinder, 23-decomposing furnace rear end oxidation section, 24-distributor, 25-calciner, 26-rotary kiln system, 27-SP boiler, 28-first high temperature exhaust fan, 29-second high temperature exhaust fan, 30-rotary slag cooler, 31-hearth, 32-separator, 33-mixing separation chamber.
Detailed Description
The invention will be further illustrated with reference to the following description and examples, which include, but are not limited to the following examples.
Example 1
The present embodiment providesThe method for treating the byproduct gypsum for producing sulfuric acid and co-producing cement clinker effectively improves SO by improving the prior art 2 Is added to the cement clinker.
As shown in fig. 1, the process flow of the present embodiment mainly includes the following steps:
1. and (3) pretreating the byproduct gypsum to obtain gypsum powder, and storing the gypsum powder for later use. The pretreatment of the byproduct gypsum mainly comprises the operations of crushing, drying, fine powder separation, dust removal and homogenization of gypsum materials.
2. Preparing auxiliary materials and a catalyst in the form of powder, and storing for later use. The catalyst prepared in this example comprises a metal oxide having Mn ions (e.g., mnO 2 ) And a metal oxide (e.g., baO) having Ba ions, wherein the metal oxide having Mn ions accounts for about 0.5% by weight of the gypsum powder, and the metal oxide having Ba ions accounts for about 1.5% by weight of the gypsum powder. The auxiliary materials and the catalyst are prepared by adopting a mature roller press raw material finish grinding process, wherein the process has the lowest electricity consumption in the cement raw material grinding process, and the electricity consumption per ton raw material is only 11kWh/t. The auxiliary materials in this example comprise sandstone, bauxite, etc., which account for about 10% of the total cement raw material weight.
3. The gypsum powder is preheated by a multi-stage furnace array preheater, so that the temperature of the gypsum powder reaches at least 750 ℃ when the gypsum powder comes out. This embodiment uses the four stages of the grate preheater design of patent CN217636840U, except that the multi-stage grate preheater in this embodiment only preheats the gypsum powder.
4. The auxiliary materials are preheated by a two-stage kiln array preheater, so that the temperature of the auxiliary materials reaches at least 520 ℃ when the auxiliary materials come out. In the embodiment, the kiln line preheater design in the patent document CN217636840U is adopted, five stages are altogether adopted, wherein C1B, C B is used for realizing the preheating of auxiliary materials, and C3B, C4B, C5B is used for preheating gypsum powder, because on one hand, the auxiliary materials can meet the temperature requirement only by preheating the two-stage kiln line preheaters of C1B, C B; on the other hand, partial gypsum powder is shunted into C3B, and is preheated by C3B, C4B, C B, so that the treatment capacity of the gypsum powder can be improved, the heat of the whole five-stage kiln row preheater can be fully utilized, and the waste of heat energy is avoided.
5. Sending the preheated gypsum powder and the catalyst into a decomposing furnace, decomposing the gypsum powder in the reducing atmosphere (reducing gas is mixed gas of carbon monoxide and sulfur steam) at 1000-1100 ℃ at the front end of the inside of the decomposing furnace to obtain SO 2 Gas and solid intermediates. The addition of the catalyst can effectively reduce the decomposition critical temperature of the gypsum powder, and the decomposition temperature in the decomposing furnace can decompose the gypsum powder only by ensuring the decomposition temperature to be in the range of 1000-1100 ℃.
6. SO for decomposing gypsum powder 2 Gas-solid separation of gas and solid intermediate product, wherein the separated SO 2 The gas is all sent to the rear end of the decomposing furnace; the separated solid intermediate product is sent to the rear end and SO of the decomposing furnace after being secondarily separated 2 The gas is mixed, and the rest two thirds of solid intermediate products continuously return to the front end in the decomposing furnace for secondary decomposition. The material distribution mode and the material distribution proportion can improve SO 2 Besides the concentration of the calcium sulfide in the solid intermediate product, the gas-solid ratio of the reduction decomposition section at the front end of the decomposing furnace and the gas-solid ratio of the oxidation section at the rear end of the decomposing furnace are always in an optimal state, so that the calcium sulfide in the solid intermediate product is converted into calcium oxide, and the secondary generation of the calcium sulfate is inhibited; meanwhile, the returning charge is continuously reduced and decomposed, so that the decomposition time of the gypsum powder in the decomposing furnace is further prolonged.
7. SO sent to the rear end of the decomposing furnace 2 The solid-phase calcium oxide is obtained by the gas and part of solid intermediate products under the conditions of weak oxidizing atmosphere and not more than 1100 ℃.
8. Solid phase calcium oxide and SO 2 Mixing the gas with the preheated auxiliary materials, performing gas-solid separation, delivering the solid-phase calcium oxide and the auxiliary materials into a rotary kiln system for calcining treatment, and finally obtaining cement clinker, and SO 2 The gas is sent to a sulfuric acid making system.
In the above-mentioned process, the total residence time of gypsum powder in the decomposing furnace is at least 60s, preferably 120s.
Example 2
The embodiment provides a treatment system designed based on the treatment method, as shown in fig. 2-4, the treatment system mainly comprises a byproduct gypsum pretreatment system, an auxiliary material and catalyst preparation system, a four-stage kiln line preheater, a five-stage kiln line preheater, a decomposing furnace device, a reducing gas preparation system, a calciner, a mixing separation chamber, a rotary kiln system, a coal dust preparation storage system, an SP boiler system and a low-heat-value coal gangue pre-combustion hot blast furnace system.
The byproduct gypsum pretreatment system is used for homogenizing and drying byproduct gypsum, obtaining gypsum powder and storing the gypsum powder. The specific process is as follows: the byproduct gypsum is transported by an automobile to enter a receiving pit of a pre-homogenization storage yard, is fed into a top belt trolley by a plate feeder to be subjected to reciprocating layered distribution, and is vertically cut by a half-bridge type scraper reclaimer on two sides to realize pre-homogenization. Then, gypsum powder obtained by the material taking machine enters a weighing bin 1 through a belt conveyor, a belt scale 2 is arranged below the weighing bin 1, the feeding amount is adjusted according to the working condition requirement of a hammer type drying crusher 4, the hammer type drying crusher 4 is fed by the feeding machine 3, and a dried heat source is from waste gas of a furnace row preheater (C1A). The byproduct gypsum is crushed and dried by a hammer type drying crusher 4, and then is collected by a fine powder separator 5 and a cloth bag dust remover 6 into a byproduct gypsum homogenizing warehouse 7 for storage homogenization. The exhaust gas discharged from the bag-type dust collector 6 is purified by the desulfurization and denitrification system 8 and then is exhausted, as shown in figure 2.
The auxiliary material and catalyst preparation system is used for preparing auxiliary materials and catalysts in powder form and storing the auxiliary materials and catalysts. The specific process is as follows: the auxiliary materials are transported by an automobile to enter a stacking shed for storage, and are crushed by a crusher and enter a batching warehouse. The catalyst enters a batching warehouse from a stacking shed through a belt conveyor. The auxiliary materials and the catalyst are respectively ground in turn.
The auxiliary materials enter a weighing steady flow bin 9 according to a proportion, are extruded into a material cake through a roller press 10, enter a V-shaped powder concentrator 11 through a circulating lifter, enter a dynamic powder concentrator 12 for further separation, and enter the weighing steady flow bin 9 after the coarse powder of the V-shaped powder concentrator 11 and the coarse powder of the dynamic powder concentrator 12 are returned again. The materials with qualified fineness are separated by a cyclone separator 13, enter a large cloth bag dust collector 15 through a circulating fan 14 to be collected, and finally enter an auxiliary material homogenizing warehouse 16 and a catalyst homogenizing warehouse 17 to be stored and homogenized respectively. The hot air also comes from the waste gas of the furnace row preheater (C1A), circularly flows among the V-shaped powder concentrator 11, the dynamic powder concentrator 12 and the circulating fan 14, dries materials, purifies the waste gas by the large cloth bag dust collector 15, and is discharged into the byproduct gypsum desulfurization and denitrification system 19 by the exhaust fan 18, and is discharged after being qualified in treatment. The air inflow of the hot air is controlled by an exhaust fan, so that the drying effect is ensured. As shown in fig. 3.
The reducing gas preparation system 20 is used for preparing the reducing gas and supplying the reducing gas into the decomposing furnace apparatus. In the embodiment, the reducing gas in the decomposing furnace device is a mixed gas of carbon monoxide and sulfur steam, wherein the carbon monoxide is incompletely generated by the combustion of fuel in the decomposing furnace; the sulfur steam is prepared by a reducing gas preparation system, and the preparation process comprises the following steps: the solid sulfur is led into a sulfur melting kettle, is indirectly heated and liquefied by steam (130-150 ℃) and is then pumped into a heating gasification furnace by a conveying pump to be rapidly gasified to form high Wen Liuhuang gas (the component is S) with the temperature of 500-800 DEG C 2 -S 6 Mainly) is metered by a metering device and is pumped into a decomposing furnace device by a special pump.
In this embodiment, carbon monoxide is used as one of the reducing gases, and the reaction formula is as follows:
CaSO 4 +2CO→CaO+CO 2 ↑+SO 2 ↑；
in this embodiment, sulfur vapor is used as another reducing gas, and the reaction formula is as follows:
①CaSO 4 +S→CaS+SO 2 ↑
②3CaSO 4 +CaS→4CaO+4SO 2 ↑
①+②2CaSO 4 +S→2CaO+3SO 2 ↑。
the coal dust preparation and storage system is used for providing fuel (coal dust) for a calciner and a rotary kiln system, and comprises the following specific processes: raw coal (or coal gangue) is transported by an automobile to enter a receiving pit of a raw coal (or coal gangue) pre-homogenizing storage yard, is fed into a top belt trolley through a plate feeder to be subjected to reciprocating layered distribution, and is vertically cut by bridge type scraper reclaimers on two sides, so that the pre-homogenizing effect is achieved. Raw coal (or coal gangue) obtained by the material taking machine enters a weighing raw coal bin (the coal gangue is discharged from the outside and enters an offline coal gangue pre-combustion hot blast stove after the coal gangue is crushed) through a belt conveyor. A belt scale is arranged below the weighing bin, the feeding amount is adjusted according to the working condition requirement of the coal vertical mill, and a dried heat source is from waste gas of a kiln head grate cooler. The pulverized coal with qualified fineness is collected by a special bag dust collector of a coal mill and enters a pulverized coal bin for storage.
The four-stage furnace row preheater is used for preheating gypsum powder, the structure of the four-stage furnace row preheater in the embodiment is the same as that of patent document CN217636840U, the pretreated byproduct gypsum powder is measured by a homogenization warehouse bottom and fed into a C2A ascending pipeline by a lifter and an air chute, and meanwhile, under the action of a first high-temperature exhaust fan 28, high-temperature flue gas generated by burning fuel in a calciner flows according to a path of C4A-C3A-C2A-C1A. Under the action of high-temperature flue gas, gypsum powder is preheated and carried into C1A, then the gypsum powder and air flow revolve in C1A, gas-solid separation occurs, and the gypsum powder enters into a rising pipeline of C3A through a discharge hole of C1A.
The gypsum powder entering the C3A rising pipeline is subjected to the same flow as the flow under the action of high-temperature flue gas, namely the flow of 'C3A rising pipeline-C2A discharge port-C4A rising pipeline-C3A'. The gypsum powder entering into C3A enters into the pipeline above the calciner through the discharge port of C3A, then continues to enter into C4A under the action of high-temperature flue gas, finally enters into the decomposing furnace device through the discharge port of C4A, the temperature of the gypsum powder at the moment reaches at least 750 ℃, the high-temperature flue gas is discharged through C1A after being reduced to medium-high temperature flue gas, and the gypsum powder is respectively sent to the byproduct gypsum pretreatment system and the auxiliary material and catalyst preparation system through special pipelines to serve as a drying heat source, and the heat of the flue gas is continuously utilized for the second time, as shown in figures 4 and 5.
The five-stage kiln line preheater in this example is the same as that of patent document CN217636840U, except that the auxiliary material is preheated by C1B, C B and then directly enters the mixing and separating chamber 33 and the gypsum powder decomposition products (solid-phase calcium oxide and SO) 2 Gas) and is mixed withThe split gypsum powder is preheated by C3B, C4B, C B and then returned to the decomposing furnace for decomposition, and the specific flow is as shown in figures 4 and 6, namely: the auxiliary material is fed into the rising pipeline of C2B, and at the same time, under the action of the second high-temperature exhaust fan 29, the high-temperature gas (mainly high-temperature SO from the mixing and separating chamber) coming out of the mixing and separating chamber 33 2 Gas) flows along a path of "C5-C4B-C3B-C2B-C1B"; under the action of high-temperature gas, auxiliary materials are preheated and carried into C1B, then enter a C3B ascending pipeline through a C1B discharge port, then continue to be preheated and carried into C2B under the action of high-temperature gas, and finally enter an air inlet pipe of the mixing separation chamber through a C2B discharge port.
Gypsum powder enters from a C4B rising pipeline and is subjected to SO at high temperature 2 The auxiliary materials and the air flow revolve in the C3B to generate gas-solid separation under the action of the air, and the auxiliary materials enter a C5 ascending pipeline through a C3B discharge hole. The gypsum powder entering the C5 rising pipeline is subjected to the same flow under the action of high-temperature gas, namely the flow of C5 rising pipeline, C4B-C4B discharge port, mixing separation chamber rising pipeline and C5, the gypsum powder entering the C5 is finally entering a decomposing furnace device through the C5 discharge port, the temperature of the gypsum powder at the moment also reaches at least 750 ℃, and the high-temperature SO 2 The gas is discharged through C1B after being cooled and sent to the SP boiler system, and finally sent to the sulfuric acid making system after being processed by the SP boiler system.
The decomposing furnace device is used for decomposing the preheated gypsum powder to obtain solid-phase calcium oxide and SO 2 And (3) gas. Unlike the decomposing furnace design in patent document CN217636840U, as shown in fig. 4, the decomposing furnace apparatus in the present embodiment includes a decomposing furnace front-end reduction decomposition section 21 (a combustion zone is provided in the decomposing furnace front-end reduction decomposition section), a suspension separation cylinder 22, and a decomposing furnace rear-end oxidation section 23, which are connected in this order. The bottom of the reduction decomposition section at the front end of the decomposing furnace is also provided with a fuel nozzle and a sulfur steam nozzle.
The suspension separating cylinder 22 is provided with a distributor 24, and the distributor 24 is used for secondarily distributing the solid intermediate product and respectively delivering the solid intermediate product to a reduction decomposition section at the front end of the decomposing furnace and an oxidation section at the rear end of the decomposing furnace. In this embodiment, the distributor is communicated with the reduction decomposition section 21 at the front end of the decomposing furnace through a heat-insulating blanking pipe, gypsum powder subjected to primary reduction decomposition is divided into two paths in the distributor 24, one path returns to the reduction decomposition section 21 at the front end of the decomposing furnace, and the other path returns to the oxidation section 23 at the rear end of the decomposing furnace, as shown in fig. 7. The heat-preserving discharging pipe controls the discharging amount, so that the respective solid-gas ratio in the reduction decomposition section 21 at the front end of the decomposing furnace and the oxidation section 23 at the rear end of the decomposing furnace is always in the optimal state. In this embodiment, the decomposed gypsum powder is secondarily divided by the distributor 24, one third of the decomposed gypsum powder is sent to the rear oxidation section 23 of the decomposing furnace, and the remaining two thirds of the decomposed gypsum powder is continuously returned to the front reduction decomposition section 21 of the decomposing furnace.
An oxidation air inlet is arranged at the upper part of the oxidation section 23 at the rear end of the decomposing furnace, and oxygen is supplied by tertiary air of the kiln. The opening of the oxidation wind inlet valve is automatically adjusted according to the requirement of the atmosphere parameters of the decomposing furnace, and the supply of oxygen enables carbon monoxide entering the oxidation section 23 at the rear end of the decomposing furnace to burn out, and along with the continuous supply of oxygen, a weak oxidation atmosphere is formed in the oxidation section 23 at the rear end of the decomposing furnace. Meanwhile, a plurality of necking openings are arranged in the reduction decomposition section 21 at the front end of the decomposing furnace and the oxidation section 23 at the rear end of the decomposing furnace (in the embodiment, the necking design in the decomposing furnace in the patent document CN217636840U is adopted), and the residence time of the gypsum powder in the decomposing furnace device can be controlled by adding disturbance of oxidation wind (the oxidation wind enters in a plurality of tangential directions). In this example, the total residence time of the gypsum powder in the decomposing furnace apparatus is 60 to 120 seconds.
The calciner 25 is used for providing a heat source for the four-stage grate preheater; the rotary kiln system 26 is used for providing a heat source for the decomposing furnace device and the five-stage kiln train preheater and for mixing materials (solid calcium oxide and SiO in auxiliary materials) from the mixing and separating chamber 2 、Al 2 O 3 、Fe 2 O 3 Equal oxide) to obtain cement clinker. Kiln gas of the rotary kiln system 26 enters from the bottom of the reduction decomposition section 21 at the front end of the decomposing furnace to accelerate the suspension of the gypsum powder entering the furnace. Fuel distribution ratio: kiln tail: kiln head=65 to 70:35 to 30. Because the oxygen concentration of kiln gas is very low, the kiln gas is in front of the decomposing furnaceThe incomplete combustion of fuel in the combustion zone of the end reduction decomposition section 21 generates a large amount of carbon monoxide, and a reducing atmosphere is naturally formed, so that gypsum powder is decomposed, and the effect of denitration is achieved; the sulfur steam is sprayed through a sulfur steam nozzle, and the theoretical amount of the sulfur steam accounts for 18.86% of the amount of the gypsum powder.
The calciner 25, the rotary kiln system 26 (including rotary kiln, tertiary air duct, grate cooler, AQC boiler), and the SP boiler system (including SP boiler 26, electric dust collector) in this embodiment are the same as those of patent document CN217636840U, so the corresponding working procedures will not be described in detail here. This embodiment differs from patent document CN217636840U in that:
(1) The kiln head high-temperature gas led out by the tertiary air pipe, a part of hot gas is supplied to the oxidation section at the rear end of the decomposing furnace (namely the kiln tertiary air) to supply oxygen for the decomposing furnace, so as to form weak oxidation atmosphere; and the other part of hot gas is supplied to the low-calorific-value coal gangue pre-combustion hot blast stove system.
(2) A heat exchanger (arranged on a pipeline connected with the SP boiler 26 and the electric dust collector) is additionally arranged in the SP boiler system, and hot air generated by the heat exchanger is utilized to be led into the low-heat-value gangue pre-combustion hot blast furnace system.
The low-heat-value gangue pre-combustion hot blast stove system is used for providing high-temperature flue gas for the calciner 25 and the decomposing furnace device. As shown in fig. 4, the low-calorific-value gangue pre-combustion hot blast furnace system mainly comprises a rotary slag cooler 30, a hearth 31 and a separator 32, wherein hot flue gas is generated by using kiln head high-temperature gas led from a tertiary air pipe and hot air generated by a heat exchanger and then is respectively sent into a calciner and a decomposing furnace device to achieve high-proportion heat replacement, so that the fuel cost of enterprises can be greatly reduced. Specifically, the low-calorific-value gangue pre-combustion hot blast furnace system recovers hot air from a heat exchanger arranged on the SP boiler system and is used for primary air of the hot blast furnace system, and kiln head high-temperature gas led from a tertiary air pipe is used as secondary air of the hot blast furnace system. See patent application number for specific design cases of low-calorific-value gangue pre-combustion hot blast stove system in the embodiment: 202320623003.5 (a comprehensive utilization system for coal gangue as fuel).
The equipment and the process can realize large-scale and large-scale development, thereby forming a series of technical equipment with the capability of treating byproduct gypsum (anhydrous basis) of 100 ten thousand tons, 200 ten thousand tons, 400 ten thousand tons and the like in a single year, and being better applied to the aspect of co-production of cement clinker by preparing sulfuric acid from industrial byproduct gypsum.
The following table shows the application effects obtained in this embodiment:
from the above, the technical effects achieved by the invention are remarkable, and compared with the prior art, the invention has outstanding substantive characteristics and remarkable progress.
The above embodiments are only preferred embodiments of the present invention, and should not be used to limit the scope of the present invention, and all the modifications or color changes that are not significant in the spirit and scope of the main body design of the present invention are still consistent with the present invention.
Claims (10)
1. A method for treating byproduct gypsum of co-production of cement clinker by sulfuric acid production is characterized by comprising the following steps:
(1) Pretreating the byproduct gypsum to obtain gypsum powder, and storing the gypsum powder for later use;
(2) Preparing auxiliary materials and catalysts in the form of powder, and storing for later use; the catalyst includes a metal oxide having Mn ions and a metal oxide having Ba ions;
(3) Preheating the gypsum powder by adopting a multi-stage furnace array preheater, so that the temperature of the gypsum powder reaches at least 750 ℃ when the gypsum powder comes out;
(4) Preheating the auxiliary materials by adopting a two-stage kiln array preheater, so that the temperature of the auxiliary materials reaches at least 520 ℃ when the auxiliary materials come out;
(5) Mixing the gypsum powder preheated in the step (3) with a catalyst, and decomposing the gypsum powder at the front end of the inside of a decomposing furnace under the conditions of reducing atmosphere and 1000-1100 ℃ to obtainSO 2 The catalyst is used for reducing the decomposition critical temperature of gypsum powder;
(6) For SO 2 Gas-solid separation of gas from solid intermediate product, wherein the separated SO 2 The gas is all sent to the rear end of the decomposing furnace; the separated solid intermediate product is sent to the rear end and SO inside the decomposing furnace by secondary material separation 2 Mixing the gases, returning the rest solid intermediate products to the front end of the inside of the decomposing furnace, mixing the solid intermediate products with gypsum powder, and continuing to decompose in a reducing atmosphere;
(7) SO sent to the rear end of the decomposing furnace 2 The solid-phase calcium oxide and SO are obtained by gas and partial solid intermediate products under the conditions of weak oxidizing atmosphere and not more than 1100 DEG C 2 A gas;
(8) Solid phase calcium oxide and SO 2 Mixing the gas with the auxiliary materials preheated in the step (4), carrying out gas-solid separation, sending the solid-phase calcium oxide and the auxiliary materials into a rotary kiln system for calcining treatment, and finally obtaining cement clinker and SO 2 The gas is sent to a sulfuric acid making system.
2. The method for treating gypsum byproduct of co-production of cement clinker by sulfuric acid production according to claim 1, wherein the metal oxide with Mn ions accounts for 0.4-0.6% of the weight of the gypsum powder, and the metal oxide with Ba ions accounts for 1-2% of the weight of the gypsum powder.
3. The method for treating gypsum byproduct in co-production of cement clinker by producing sulfuric acid according to claim 1 or 2, wherein the reducing gas in the reducing atmosphere is a mixed gas of sulfur vapor and carbon monoxide.
4. The method for treating gypsum byproduct in co-production of cement clinker by sulfuric acid production according to claim 3, wherein in the step (6), one third of the solid intermediate product is sent to the rear end of the interior of the decomposing furnace, and the remaining two thirds of the solid intermediate product is returned to the front end of the interior of the decomposing furnace.
5. The method for treating gypsum byproduct of co-production of sulfuric acid and cement clinker as set forth in claim 4, wherein the total residence time of the gypsum powder in the decomposing furnace is at least 60s.
6. The method for treating gypsum byproduct in co-production of cement clinker in sulfuric acid production according to claim 5, wherein in the step (3), a part of gypsum powder is split into a multi-stage kiln-line preheater for preheating, and the preheated gypsum powder is fed into a decomposing furnace.
7. A system for realizing the by-product gypsum treatment method according to any one of claims 1 to 6, comprising:
the byproduct gypsum pretreatment system is used for crushing, drying and homogenizing byproduct gypsum to obtain gypsum powder and storing the gypsum powder;
the auxiliary material and catalyst preparation system is used for preparing auxiliary materials and catalysts in the form of powder materials and storing the auxiliary materials and the catalysts;
the multi-stage furnace array preheater is used for preheating gypsum powder;
the two-stage kiln array preheater is used for preheating auxiliary materials;
the decomposing furnace device is used for decomposing the preheated gypsum powder to obtain solid-phase calcium oxide and SO 2 A gas; the decomposing furnace device comprises a decomposing furnace front-end reduction decomposing section, a suspension separating cylinder, a decomposing furnace rear-end oxidation section and a distributor arranged on the suspension separating cylinder, which are sequentially connected, wherein a combustion area is arranged in the decomposing furnace front-end reduction decomposing section; the distributor is used for carrying out secondary distribution on the solid intermediate product and respectively delivering the solid intermediate product to a reduction decomposition section at the front end of the decomposing furnace and an oxidation section at the rear end of the decomposing furnace;
a mixing separation chamber for mixing solid-phase calcium oxide and SO 2 Gas and auxiliary materials are subjected to gas-solid separation; isolated SO 2 The gas is discharged through the kiln line preheater and simultaneously provides a heat source for the kiln line preheater;
the reducing gas preparation system is used for preparing sulfur steam and spraying the sulfur steam from a combustion zone in the decomposing furnace;
a calciner for providing a heat source to the multi-stage train preheater;
the rotary kiln system is used for providing kiln gas into the decomposing furnace device and processing the mixed material of the solid-phase calcium oxide and the auxiliary materials from the mixing separation chamber to obtain cement clinker; simultaneously, oxygen is also provided for the oxidation section at the rear end of the decomposing furnace.
8. The system of claim 7, wherein the distributor is connected to the front reduction decomposition section of the decomposing furnace and the rear oxidation section of the decomposing furnace through a heat-insulating blanking pipe, respectively.
9. The system according to claim 7 or 8, further comprising a multi-stage kiln line preheater with an air outlet connected to the two-stage kiln line preheater and a discharge outlet connected to the reduction decomposition section at the front end of the decomposing furnace for preheating gypsum powder; the air inlet of the multi-stage kiln array preheater is connected with the mixing separation chamber.
10. The system of claim 9, further comprising a coal dust preparation storage system for providing fuel to the calciner and rotary kiln systems, and a low heating value gangue pre-combustion hot blast stove system for providing high temperature flue gas to the calciner and kiln assemblies.
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