Device for preparing calcium carbonate and calcium sulfate by wet carbon sequestration of desulfurized fly ash

Abstract

The utility model discloses a device for preparing calcium carbonate and calcium sulfate from desulfurized fly ash through wet carbon sequestration. Comprising a lime kiln, a lime digestion and emulsification tank, a leaching tank, a first filtering unit, a second filtering unit, a third filtering unit, a fourth filtering unit, a purification reaction kettle, a carbonization and oxidation reaction kettle, a light calcium synthesis reaction kettle, a calcium carbonate synthesis reaction kettle, a common calcium carbonate drying unit, a calcium sulfate drying unit and an ammonia chloride solution buffer tank, the first recovery tank is used for collecting ammonia gas escaped from the leaching tank, the first filtering unit, the purification reaction kettle, the second filtering unit, the third filtering unit and the calcium sulfate synthesis reaction kettle and supplying the ammonia gas to the light calcium synthesis reaction kettle. The ammonia gas is used for adjusting the PH, so that carbon dioxide is dissolved in water to form carbonic acid, and carbonate reacts with calcium ions to form calcium carbonate. And the escaped ammonia gas is collected and reused. The ammonia gas utilization rate is improved. And the consumption of ammonia gas is reduced.

Description

Technical Field

[0001] This utility model relates to an apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash, belonging to the field of chemical equipment technology. Background Technology

[0002] Light calcium carbonate can be used as a filler in industries such as rubber, plastics, papermaking, coatings, and inks. It is widely used in organic synthesis, metallurgy, glass, and asbestos production. Calcium sulfate, with the chemical formula CaSO4, is a white crystalline powder. It has applications in food processing, construction, and papermaking. Currently, the processes for preparing light calcium carbonate and calcium sulfate have shortcomings, including low ammonia utilization and partial precipitation of buffer substances. Utility Model Content

[0003] To overcome the above-mentioned shortcomings, the purpose of this utility model is to provide an apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is: an apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash, comprising calcium sulfite, a lime kiln, quicklime, a lime digestion and emulsification tank, a leaching tank, a first filtration unit, a second filtration unit, a third filtration unit, a fourth filtration unit, a purification reaction vessel, a carbonation and oxidation reaction vessel, a light calcium synthesis reaction vessel, a calcium carbonate synthesis reaction vessel, a common calcium carbonate drying unit, a calcium sulfate drying unit, an ammonium chloride solution buffer tank, and a calcium sulfate synthesis reaction vessel;

[0005] The lime kiln produces carbon dioxide; quicklime forms lime slurry in the lime slaking emulsification tank; calcium sulfite is fed into the leaching tank, and ammonium chloride solution is fed into the leaching tank from the ammonium chloride solution buffer tank. The leaching tank feeds leachate into the first filtration unit. The filtrate from the first filtration unit and the lime slurry are fed into the purification reactor. The product from the purification reactor enters the second filtration unit. The filtrate from the second filtration unit, along with the carbon dioxide and ammonia produced by the lime kiln, enters the light calcium synthesis reactor. The product from the light calcium synthesis reactor is fed into the third filtration unit. The third filtration unit produces light calcium carbonate. The filtrate from the third filtration unit enters the ammonium chloride solution buffer tank.

[0006] Carbon dioxide, air, ammonium carbonate solution, and the filter cake produced by the first filtration unit are fed into the carbonation oxidation reactor. The product of the carbonation oxidation reactor is fed into the fourth filtration unit. The filter cake produced by the fourth filtration unit is ordinary calcium carbonate. The filtrate and lime slurry produced are fed into the calcium sulfate synthesis reactor. The calcium sulfate synthesis reactor produces calcium sulfate.

[0007] The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash further includes a first recovery tank, which collects ammonia gas escaping from the leaching tank, the first filtration unit, the purification reactor, the second filtration unit, the third filtration unit, and the calcium sulfate synthesis reactor, and supplies ammonia gas to the light calcium synthesis reactor.

[0008] The present invention is further configured such that: the apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash also includes a circulating water buffer tank, the reaction liquid discharged from the calcium carbonate synthesis reactor is input into the circulating water buffer tank, and the digested water produced by the circulating water buffer tank is input into the lime digestion emulsification tank.

[0009] The present invention is further configured such that the apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash also includes a second recovery tank, which collects carbon dioxide escaping from the circulating water buffer tank, the carbonization oxidation reactor, the fourth filtration unit, and the calcium sulfate synthesis reactor, as well as circulating water from the circulating water buffer tank, and outputs ammonium carbonate solution to the carbonization oxidation reactor.

[0010] A further feature of this invention is that the second recycling tank is equipped with a waste gas exhaust mechanism.

[0011] The present invention is further configured such that: the first recovery tank outputs ammonia gas to the second recovery tank.

[0012] The present invention is further configured such that: the second recovery tank collects the ammonia and carbon dioxide escaping from the light calcium synthesis reactor.

[0013] The present invention is further configured such that: the ordinary calcium carbonate is dried by the drying unit and then packaged, and the carbon dioxide produced by the drying unit is collected by the second recovery tank.

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: By setting up a first recovery tank, the first recovery tank collects the ammonia gas escaping from the leaching tank, the first filtration unit, the purification reactor, the second filtration unit, the third filtration unit, and the calcium sulfate synthesis reactor, and supplies ammonia gas to the light calcium synthesis reactor. The ammonia gas is used to adjust the pH, so that carbon dioxide dissolves in water to form carbonic acid, and carbonate ions react with calcium ions to form calcium carbonate. The escaped ammonia gas is collected and reused, thus improving the utilization rate of ammonia gas and reducing its consumption. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash according to a preferred embodiment of the present invention. Detailed Implementation

[0016] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0017] See appendix Figure 1 As shown in this embodiment, an apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash includes the following main chemical reaction processes:

[0018] CaSO3→Ca 2+ +SO3 2-

[0019] CO2 + H2O → CO3 2- +2H +

[0020] Ca 2+ +CO3 2- →CaCO3↓

[0021] SO3 2- +1 / 2O2→SO4 2-

[0022] NH3·H2O→NH4 + +OH -

[0023] This embodiment of an apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash includes calcium sulfite, lime kiln, quicklime, lime digestion emulsification tank, leaching tank, first filtration unit, second filtration unit, third filtration unit, fourth filtration unit, purification reactor, carbonation oxidation reactor, light calcium synthesis reactor, calcium carbonate synthesis reactor, ordinary calcium carbonate drying unit, calcium sulfate drying unit, ammonium chloride solution buffer tank, and calcium sulfate synthesis reactor.

[0024] Calcium sulfite is derived from semi-dry desulfurization ash. Carbon dioxide is produced in the lime kiln; quicklime forms a lime slurry in the lime slaking emulsification tank; calcium sulfite is fed into the leaching tank; an ammonium chloride solution buffer tank feeds ammonium chloride solution into the leaching tank; the leaching tank feeds leachate into the first filtration unit; the filtrate from the first filtration unit and the lime slurry are fed into the purification reactor; the product from the purification reactor enters the second filtration unit; the filtrate from the second filtration unit, along with carbon dioxide and ammonia produced in the lime kiln, enters the light calcium synthesis reactor; the product from the light calcium synthesis reactor is fed into the third filtration unit; the third filtration unit produces light calcium carbonate; and the filtrate from the third filtration unit enters the ammonium chloride solution buffer tank.

[0025] Carbon dioxide, air, ammonium carbonate solution, and the filter cake produced by the first filtration unit are fed into the carbonation oxidation reactor. The product of the carbonation oxidation reactor is fed into the fourth filtration unit. The filter cake produced by the fourth filtration unit is ordinary calcium carbonate. The filtrate and lime slurry produced are fed into the calcium sulfate synthesis reactor. The calcium sulfate synthesis reactor produces calcium sulfate.

[0026] The apparatus for wet carbon fixation of desulfurized ash to prepare calcium carbonate and calcium sulfate further includes a first recovery tank. The first recovery tank collects ammonia gas escaping from the leaching tank, the first filtration unit, the purification reactor, the second filtration unit, the third filtration unit, and the calcium sulfate synthesis reactor, and supplies ammonia gas to the light calcium synthesis reactor. Preferably, the collection method involves connecting the first recovery tank to the top of the leaching tank, the first filtration unit, the purification reactor, the second filtration unit, the third filtration unit, and the calcium sulfate synthesis reactor via a pipeline, with a gas pump installed in the pipeline. The first recovery tank is connected to the light calcium synthesis reactor via another pipeline. The filter cake produced by the second filtration unit is input into a purification slag buffer chamber, which then inputs the filter cake into a carbonization oxidation reactor.

[0027] The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash also includes a circulating water buffer tank. The reaction liquid discharged from the calcium carbonate synthesis reactor is input into the circulating water buffer tank, and the digested water produced by the circulating water buffer tank is input into the lime digestion emulsification tank.

[0028] The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash further includes a second recovery tank. The second recovery tank collects carbon dioxide escaping from the circulating water buffer tank, the carbonization oxidation reactor, the fourth filtration unit, and the calcium sulfate synthesis reactor, as well as circulating water from the circulating water buffer tank, and outputs ammonium carbonate solution to the carbonization oxidation reactor.

[0029] The second recovery tank is equipped with a waste gas venting mechanism. The first recovery tank outputs ammonia gas into the second recovery tank. The second recovery tank collects the ammonia gas and carbon dioxide escaping from the light calcium synthesis reactor. The ordinary calcium carbonate is dried in a drying unit and then packaged; the carbon dioxide produced by the drying unit is collected by the second recovery tank.

[0030] Preferably, the first filter unit, the second filter unit, the third filter unit, and the fourth filter unit are all filter presses or ceramic filters.

[0031] In summary, the principle of the apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash as shown in this utility model is as follows: A first recovery tank is set up to collect ammonia gas escaping from the leaching tank, the first filtration unit, the purification reactor, the second filtration unit, the third filtration unit, and the calcium sulfate synthesis reactor, and to supply ammonia gas to the light calcium synthesis reactor. The ammonia gas is used to adjust the pH, so that carbon dioxide dissolves in water to form carbonic acid, and carbonate ions react with calcium ions to form calcium carbonate. The escaped ammonia gas is collected and reused, thus improving the utilization rate of ammonia gas and reducing its consumption.

[0032] The second recovery tank collects carbon dioxide escaping from the circulating water buffer tank, the carbonization oxidation reactor, the fourth filtration unit, the calcium sulfate synthesis reactor, and the first recovery tank, as well as circulating water from the circulating water buffer tank. It also collects carbon dioxide and ammonia escaping from the light calcium synthesis reactor and outputs ammonium carbonate solution to the carbonization oxidation reactor. This further improves the utilization rate of ammonia and carbon dioxide and saves on raw material consumption.

Claims

1. An apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash, comprising calcium sulfite, a lime kiln, quicklime, a lime digestion and emulsification tank, a leaching tank, a first filtration unit, a second filtration unit, a third filtration unit, a fourth filtration unit, a purification reactor, a carbonation and oxidation reactor, a light calcium synthesis reactor, a calcium carbonate synthesis reactor, a common calcium carbonate drying unit, a calcium sulfate drying unit, an ammonium chloride solution buffer tank, and a calcium sulfate synthesis reactor; The lime kiln produces carbon dioxide; quicklime forms lime slurry in the lime slaking emulsification tank; calcium sulfite is fed into the leaching tank, and ammonium chloride solution is fed into the leaching tank from the ammonium chloride solution buffer tank. The leaching tank feeds leachate into the first filtration unit. The filtrate from the first filtration unit and the lime slurry are fed into the purification reactor. The product from the purification reactor enters the second filtration unit. The filtrate from the second filtration unit, along with the carbon dioxide and ammonia produced by the lime kiln, enters the light calcium synthesis reactor. The product from the light calcium synthesis reactor is fed into the third filtration unit. The third filtration unit produces light calcium carbonate. The filtrate from the third filtration unit enters the ammonium chloride solution buffer tank. Carbon dioxide, air, ammonium carbonate solution, and the filter cake produced by the first filtration unit are fed into the carbonation oxidation reactor. The product of the carbonation oxidation reactor is fed into the fourth filtration unit. The filter cake produced by the fourth filtration unit is ordinary calcium carbonate. The filtrate and lime slurry produced are fed into the calcium sulfate synthesis reactor. The calcium sulfate synthesis reactor produces calcium sulfate. Its features are, The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash further includes a first recovery tank, which collects ammonia gas escaping from the leaching tank, the first filtration unit, the purification reactor, the second filtration unit, the third filtration unit, and the calcium sulfate synthesis reactor, and supplies ammonia gas to the light calcium synthesis reactor.

2. The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash according to claim 1, characterized in that, The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash also includes a circulating water buffer tank. The reaction liquid discharged from the calcium carbonate synthesis reactor is input into the circulating water buffer tank, and the digested water produced by the circulating water buffer tank is input into the lime digestion emulsification tank.

3. The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash according to claim 2, characterized in that, The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash further includes a second recovery tank. The second recovery tank collects carbon dioxide escaping from the circulating water buffer tank, the carbonization oxidation reactor, the fourth filtration unit, and the calcium sulfate synthesis reactor, as well as circulating water from the circulating water buffer tank, and outputs ammonium carbonate solution to the carbonization oxidation reactor.

4. The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash according to claim 3, characterized in that, The second recovery tank is equipped with an exhaust gas discharge mechanism.

5. The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash according to claim 4, characterized in that, The first recovery tank outputs ammonia gas into the second recovery tank.

6. The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash according to claim 5, characterized in that, The second recovery tank collects the ammonia and carbon dioxide escaping from the light calcium synthesis reactor.

7. The apparatus for preparing calcium carbonate and calcium sulfate by wet carbon fixation of desulfurization ash according to claim 6, characterized in that, The ordinary calcium carbonate is dried in the drying unit and then packaged. The carbon dioxide produced by the drying unit is collected by the second recovery tank.

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