A kind of sulfuric acid flue gas cleaning process unitTechnical field
Involved in the present invention is sulfuric acid industry technical field, relates in particular to the flue gas cleaning process unit in pyrite-based sulfuric acid production production process.
Background technology
In pyrite-based sulfuric acid production technique, producing SO2In the process of furnace gas, there are many tiny solid particles and impurity to enter SO2Furnace gas, then directly enters follow-up system and produces sulfuric acid, and they not only can, to causing obstruction and the corrosion of equipment, also can affect product quality. Therefore, must be in advance to SO2Furnace gas carries out purification and impurity removal, then enters subsequent handling and produces standard compliant sulfuric acid.
Existing pyrite-based sulphuric acid plant, uses the technological process that tower-groove is integrated or tower-groove separates mostly, and adopts dilute sulfuric acid circulation cleaning to purify furnace gas. These two kinds of technological processes are in flue gas cleaning process, in furnace gas, a large amount of dust and impurity wash to purify by dilute sulfuric acid and enter in dilute sulfuric acid, therefore, and the circulation through dilute sulfuric acid in the long period, wherein solid content is increased, and be deposited in tower, groove, pipeline and equipment, result in blockage, and cleaning time is wasted time and energy, also there is security risk simultaneously, and cause the dilute sulfuric acid solid content of discharge higher, and be difficult to utilize, be often used as wastewater treatment. As water carries out washing, purifying, can consume a large amount of waste water, production cost can increase greatly, and produces a large amount of dilute sulfuric acids and be difficult to disposal and utilization, has also increased environmental protection risk simultaneously.
Summary of the invention
The present invention seeks to first to enter scrubbing tower for furnace gas and carry out acid-scrubbing cleaning, a large amount of dust impurity is gone the solid impurity in dilute sulfuric acid mainly just to concentrate on this link by eccysis, consider to reduce the solid impurity content in dilute sulfuric acid as far as possible in this link, and the dilute sulfuric acid of discharging is carried out being used after filtration treatment. Reduce environmental protection risk.
For this reason, the present invention carries out according to the following steps:
Apparatus of the present invention are mainly by sulfur dioxide stripping tower 1, diluted acid filter 2, scrubbing tower 3, diluted acid settling tank 4, dilute acid bath 5, thin acid pump 6, conical setting tank 7, circulation acid tank 8, scrubbing tower circulating pump 9, acid dredge pump 10, cooling tower 11, cooling tower circulating pump 12, acid cooler 13, one-level electrostatic precipitator 14, secondary electrostatic precipitator 15 forms; Sulfur dioxide stripping tower 1, dilute acid bath 5, diluted acid filter 2, scrubbing tower 3, diluted acid settling tank 4, subsider, circulation acid tank, cooling tower 11, acid cooler 13, one-level electrostatic precipitator 14, secondary electrostatic precipitator 15 is that furnace gas Trunk Line is connected by pipeline, utilizes system negative pressure that the sulphur dioxide gas parsing in diluted acid is recovered in production system; Liquid, diluted acid be by thin acid pump 6, scrubbing tower circulating pump 9, and sour dredge pump 10, cooling tower circulating pump 12 use pipelines connect each corresponding tower, groove completes the washing work to furnace gas;
Scrubbing tower 3 is designed to tower-groove unpack format, at the bottom of scrubbing tower, be designed to taper, dilute sulfuric acid enters from scrubbing tower top, after washing furnace gas, certainly flow into cone settling tank 7 through conical bottom, dilute sulfuric acid is in subsider after sedimentation, clear liquid flows into scrubbing tower circulation acid tank 8, use as scrubbing tower recycle acid, the sludge depositing is delivered to sulfate slag stockyard through cone settling tank bottom by sour dredge pump 10 and is mixed with dry slag, scrubbing tower recycle acid trench bottom is also designed to taper, the sour mud of being convenient to deposition is collected, and is together discharged by sour dredge pump 10;
Furnace gas enters cooling tower cooling and moves heat after washing impurity-removing, cooling tower is designed to tower-groove one form, and be conical lower portion, tower bottom is used as the cooling tower circulating slot of cooling tower, conical lower portion is with collecting the sour mud of deposition, then by gravity flow mode timing discharged to subsider, avoid sour mud deposition too much pipeline to be blocked, in cooling tower, unnecessary diluted acid is discharged to scrubbing tower circulating slot through overfall.
Cooled furnace gas enters one-level electrostatic precipitator 14, and secondary electrostatic precipitator 15 arrives subsequent handling after removing acid mist again, and diluted acid overflow to the cool cycles under electrostatic precipitator removes is used;
The dilute sulfuric acid that scrubbing tower circulating pump is got separates part according to the condition of production and enters filter filtration, after the sulfur dioxide that clear liquid is deviate to dissolve through sulfur dioxide stripping tower, enter diluted acid settling tank, then flow automatically to dilute acid bath and send into other local uses by thin acid pump 6, filter residue drains into subsider by automatic valve timing.
Effect of the present invention and advantage
1, this technique is simple, easy to operate, can effectively reduce pipeline and equipment and stop up, and has reduced cleaning up cost and down time simultaneously.
2, the dilute sulfuric acid impurity content of generation is few, concentration is higher, can fully utilize.
3, can reduce industrial water amount, have good economic benefits and environmental benefit.
Brief description of the drawings
Fig. 1. apparatus structure schematic diagram of the present invention.
In Fig. 1,1. sulfur dioxide stripping tower, 2. diluted acid filter, 3. scrubbing tower, 4. diluted acid settling tank, 5. dilute acid bath, 6. thin acid pump, 7. conical setting tank, 8. circulation acid tank, 9. scrubbing tower circulating pump, 10. sour dredge pump, 11. cooling towers, 12. cooling tower circulating pumps, 13. acid coolers, 14. one-level electrostatic precipitators, 15. secondary electrostatic precipitators.
Detailed description of the invention
Embodiment 1
Use this law as example taking 400,000 tons/year of pyrite-based sulphuric acid plants of certain company. Former technique: need every year the cleaning 4～5 times of stopping, each cleaning need to be spent 2～3 day time, 5000 yuan of left and right of each cleaning up cost, the about 8t/h of mass percent 12% left and right dilute sulfuric acid of generation per hour, all when waste water is processed. Adopt after this law: build a set of flue gas cleaning process unit according to this law, by sulfur dioxide stripping tower 1, diluted acid filter 2, scrubbing tower 3, diluted acid settling tank 4, dilute acid bath 5, thin acid pump 6, conical setting tank 7, circulation acid tank 8, scrubbing tower circulating pump 9, sour dredge pump 10, cooling tower 11, cooling tower circulating pump 12, acid cooler 13, one-level electrostatic precipitator 14, secondary electrostatic precipitator 15 forms; Sulfur dioxide stripping tower 1, dilute acid bath 5, diluted acid filter 2, scrubbing tower 3, diluted acid settling tank 4, subsider, circulation acid tank, cooling tower 11, acid cooler 13, one-level electrostatic precipitator 14, secondary electrostatic precipitator 15 is that furnace gas Trunk Line is connected by pipeline, utilizes system negative pressure that the sulphur dioxide gas parsing in diluted acid is recovered in production system; Liquid, diluted acid be by thin acid pump 6, scrubbing tower circulating pump 9, and sour dredge pump 10, cooling tower circulating pump 12 use pipelines connect each corresponding tower, groove completes the washing work to furnace gas;
Scrubbing tower 3 is designed to tower-groove unpack format, at the bottom of scrubbing tower, be designed to taper, dilute sulfuric acid enters from scrubbing tower top, after washing furnace gas, certainly flow into cone settling tank 7 through conical bottom, dilute sulfuric acid is in subsider after sedimentation, clear liquid flows into scrubbing tower circulation acid tank 8, use as scrubbing tower recycle acid, the sludge depositing is delivered to sulfate slag stockyard through cone settling tank bottom by sour dredge pump 10 and is mixed with dry slag, scrubbing tower recycle acid trench bottom is also designed to taper, the sour mud of being convenient to deposition is collected, and is together discharged by sour dredge pump 10;
Furnace gas enters cooling tower cooling and moves heat after washing impurity-removing, cooling tower is designed to tower-groove one form, and be conical lower portion, tower bottom is used as the cooling tower circulating slot of cooling tower, conical lower portion is with collecting the sour mud of deposition, then by gravity flow mode timing discharged to subsider, avoid sour mud deposition too much pipeline to be blocked, in cooling tower, unnecessary diluted acid is discharged to scrubbing tower circulating slot through overfall.
Cooled furnace gas enters one-level electrostatic precipitator 14, and secondary electrostatic precipitator 15 arrives subsequent handling after removing acid mist again, and diluted acid overflow to the cool cycles under electrostatic precipitator removes is used;
The dilute sulfuric acid that scrubbing tower circulating pump is got separates part according to the condition of production and enters filter filtration, after the sulfur dioxide that clear liquid is deviate to dissolve through sulfur dioxide stripping tower, enter diluted acid settling tank, then flow automatically to dilute acid bath and send into other local uses by thin acid pump 6, filter residue drains into subsider by automatic valve timing.
By operation in 3 years, the annual cleaning of stopping reduced to 1～2 time, and each cleaning only needs 1 day, and each cleaning up cost reduces to 2000 yuan of left and right, and the about 4t/h of 25% left and right dilute sulfuric acid of generation per hour, is all utilized. By the enforcement of this law, good economic benefits and environmental benefit are obtained.