CN101613161B

CN101613161B - Method for treating and using sintering flue gas desulphurization wastewater and special device thereof

Info

Publication number: CN101613161B
Application number: CN2008101227106A
Authority: CN
Inventors: 刘经滂; 谭培龙; 储德昌; 罗太锋
Original assignee: Shanghai Meishan Iron and Steel Co Ltd
Current assignee: Shanghai Meishan Iron and Steel Co Ltd
Priority date: 2008-06-26
Filing date: 2008-06-26
Publication date: 2011-04-20
Anticipated expiration: 2028-06-26
Also published as: CN101613161A

Abstract

The invention relates to a method for treating sintering flue gas desulphurization wastewater and a special device thereof, which belongs to the technical field of environmental protection. The method comprises the following steps: after the sintering flue gas desulphurization wastewater containing Cl<-> and SO4<2-> is clarified, drawing out the wastewater supernatant fluid; detecting the concentration of the SO4<2-> in the drawn-out wastewater supernatant fluid, and adding corresponding amount of quicklime to perform sufficient chemical reactions so as to remove the SO4<2-> in the wastewater supernatant fluid; when the intermediate solution after removing the SO4<2-> is clarified, drawing out the supernatant liquid of the intermediate solution; detecting the concentration of the Cl<-> in the supernatant liquid of the drawn-out intermediate solution, adding corresponding amount of the quicklime, introducing compressed air and stirring the mixture to prepare CaCl2 solution with the required concentration; and conveying and spraying the prepared CaCl2 solution on a sintering ore. The method and the special device achieve the treatment of the sintering flue gas desulphurization wastewater, simultaneously achieve the recycling of wastes, can further obtain useful byproducts, have remarkable environmental protection effect, and generate ideal economic benefits.

Description

The sintering flue gas desulfurization wastewater treatment utilizes method and specific equipment

Technical field

Invention relates to a kind of method of wastewater treatment, and especially a kind of sintering flue gas desulfurization wastewater treatment method also relates to the suite of equipment of realizing this method simultaneously, belongs to environmental protection technical field.

Background technology

Understand according to the applicant, the steel enterprise sintering flue gas generally adopts alkaline process to absorb the purpose that SO2 in the flue gas reaches desulfurization at present.Yet, contain the Cl of higher concentration in the waste water that this type of sweetening process produces ^-, SO ₄ ^2-(for example, the Cl in certain Iron And Steel Company's desulfurization wastewater ^-, SO ₄ ^2-Content is respectively 5100-5800mg/l, 1500-2100mg/l, can not cause secondary pollution if do not handle directly just to efflux.So far, the waste water that steel enterprise sintering flue gas desulfurization is produced does not still have efficient ways.

On the other hand, CaCl sprays in order to reduce the low temperature reduction degradation index of finished product agglomerate, generally to adopt in iron and steel enterprise on agglomerate ₂The method of solution.Therefore need to consume a large amount of CaCl ₂(for example, certain Iron And Steel Company is used to spray the pure CaCl of agglomerate ₂Consumption is 0.1kg/t-s), the result has increased production cost.

Summary of the invention

The primary and foremost purpose of invention is: handle the problem that produces waste water at above-mentioned existing steel enterprise sintering flue gas desulfurization, propose a kind of sintering flue gas desulfurization wastewater treatment and utilize method, this method had both realized the processing of desulfurization wastewater, again can be by the processing of sintering flue gas desulfurization waste water being produced the CaCl with practical value ₂Solution.Simultaneously, the present invention also will provide the special complete equipment of this method of realization.

Further aim of the present invention is: in above-mentioned wastewater treatment process, generate useful gypsum by-product, thereby help further to increase economic efficiency.

In order to reach above purpose, the sintering flue gas desulfurization wastewater treatment of invention utilizes method may further comprise the steps:

The first step, Cl to be contained ^-, SO ₄ ^2-After the waste water clarification of sintering flue gas desulfurization, wastewater supernatant fluid is drawn;

The SO in the wastewater supernatant fluid is drawn in second step, detection ₄ ^2-Concentration ' add the unslaked lime of respective amount,

Make it fully following chemical reaction to take place, remove the SO in the wastewater supernatant fluid ₄ ^2-

CaO+3H ₂O+SO ₄ ^2-→CaSO ₄·2H ₂O↓+2OH ^-

The 3rd step, SO to be removed ₄ ^2-After intermediate liquid clarification after, draw the supernatant liquor of this intermediate liquid;

The Cl in the intermediate liquid supernatant liquor is drawn in the 4th step, detection ^-Concentration, the unslaked lime of adding respective amount,

And feed the pressurized air stirring, be made into the CaCl of desired concn ₂Solution;

The 5th the step, with the CaCl that is made into ₂Solution is carried and is sprayed onto on the agglomerate.

The suite of equipment of realizing aforesaid method of the present invention comprises Buffer Pool, settling bowl and finished product pond; Described Buffer Pool is used to collect and contains Cl ^-, SO ₄ ^2-Sintering flue gas desulfurization waste water, and after making it clarification; The overflow port of described Buffer Pool leads to settling bowl, is used for wastewater supernatant fluid is drawn out to settling bowl; Described settling bowl is used to collect wastewater supernatant fluid, and removes the SO in the wastewater supernatant fluid behind the unslaked lime to be added ₄ ^2-, generate intermediate liquid; The overflow port of described settling bowl leads to the finished product pond, is used for the supernatant liquor of intermediate liquid is drawn out to the finished product pond; Described finished product pond is used to collect the intermediate liquid supernatant liquor, and unslaked lime to be added, feeds pressurized air and stirs, and is made into the CaCl of desired concn ₂Solution; Described finished product pond leads to agglomerate through transfer line, is used for the CaCl that will be made into ₂Solution is carried and is sprayed onto on the agglomerate.

In order to reach further purpose, after second of aforesaid method goes on foot, also with sedimentary aqueous gypsum (CaSO ₄2H ₂O) transport to dewatering unit and dewater, generate byproduct.In the corresponding suite of equipment, the bottom of described settling bowl also leads to dewatering unit by slush pump, is used for aqueous gypsum (CaSO ₄2H ₂O) transporting to dewatering unit dewaters.

Understand easily, after adopting method of the present invention, not only realized the processing of sintering flue gas desulfurization waste water with practicable technical process, thus compliance with environmental protection requirements, simultaneously with cheap facility investment, realize refuse reclamation, also can further obtain useful byproduct, both had the remarkable environmental benefit, also produced ideal benefits, achieve many things at one stroke, very ingenious reasonable, can be widely used in each iron and steel enterprise.

Description of drawings

Below in conjunction with accompanying drawing invention is further described.

Fig. 1 is the suite of equipment structural representation of an embodiment of invention.

Among the figure: 1-Buffer Pool, 2-valve, the acidproof pipeline of 3-, 4-settling bowl, 5-slush pump, 6-finished product pond, 7-water pump, 8-compressed air pipe

Embodiment

Embodiment one

The sintering flue gas desulfurization wastewater treatment of present embodiment utilizes the method technical process as shown in Figure 1, flue gas desulfurization waste-water flows into Buffer Pool 1, the small amount of solid impurity that wherein accompanies is in Buffer Pool generation sedimentation, open make behind the valve 2 supernatant liquor by acidproof pipeline 3 overflows to settling bowl 4, settling bowl 4 constitutes by two groups that walk abreast, and uses in turn.During ordinary production,, when waiting to reach certain depth, close its corresponding valve, by the effective volume V of settling bowl 4 and the SO in the desulfurization wastewater by closing or Open valve can make supernatant liquor overflow in the Buffer Pool 1 to one of them settling bowl 4 ₄ ^2-Concentration is the association reaction equation again:

CaO+3H ₂O+SO ₄ ^2-→CaSO ₄·2H ₂O↓+2OH ^-

Calculate the amount of the unslaked lime (CaO) that need in settling bowl, add, treat CaSO ₄2H ₂After the O sedimentation finishes, open valve the supernatant liquor overflow of this settling bowl (is opened the sedimentation operation that respective valves is carried out another settling bowl) simultaneously to finished product pond 6.After treating that supernatant liquor is first-class and finishing, close this flow spill valve, open slush pump 5 and the corresponding valve CaSO at the bottom of with the pond ₄2H ₂The gypsum dehydration system that O is delivered to desulfurization process dewaters and obtains by-produced gypsum, according to volume that flows into finished product pond 6 liquid and the Cl in the desulfurization wastewater ^-Solubility adds corresponding unslaked lime (CaO) and the CaCl that is mixed with satisfied sprinkling agglomerate demand concentration under pressurized air 8 stirring condition is being arranged ₂Solution.Be delivered to the sprinkling that shower nozzle carries out agglomerate by water pump 7, use in turn, make the carrying out that whole process flow can continous-stable by two groups of settling bowls.

Below be once actual treating processes record: open the Buffer Pool valve earlier, supernatant liquor flows into settling bowl, and (U.S. Dai An company) detects Cl in the solution with 90 type ion chromatographs ^-, SO ₄ ^2-Concentration is respectively 5498mg/l, 1900mg/l, and when treating that supernatant liquor reaches specified liquid level in settling bowl (being carved with liquid level line in the settling bowl), the liquor capacity that obtains in this moment of the pond is 70m ³, SO in the solution then ₄ ^2-Content be:

SO ₄ ^2-：1900×70×1000＝133kg

In settling bowl, add unslaked lime CaO, following reaction takes place:

CaO+3H ₂O+SO ₄ ^2-→CaSO ₄·2H ₂O↓+2OH ^-

The amount that can calculate the unslaked lime CaO that needs adding according to reaction equation is:

(133×56)÷98＝76kg

Wherein: 56 is the CaO formula weight;

98 is SO ₄ ^2-Formula weight

Turn on agitator stirred after 15 minutes, closed agitator, after settlement separate 15 minutes, opened the settling bowl valve, when treating supernatant liquor inflow finished product pond appointment liquid level (being carved with liquid level line in the settling bowl), and valve-off, the CaSO of settling bowl bottom ₄2H ₂O is delivered to vacuum belt dewaterer (manufacturing of Kunshan Fei Luo company) by slush pump, and dewatering obtains gypsum, and the liquor capacity in the finished product pond is 68.5m at this moment ³, Cl in the solution then ^-Content is:

Cl ^-：5498×68.5×1000＝35.74kg

According to reaction equation:

CaO+H ₂O+2Cl ^-→CaCl ₂+2OH ^-

Can calculate the CaO amount that needs to add is:

(35.74×56)÷71＝28.19kg

Wherein: 56 is the CaO formula weight;

71 is 2Cl ^-Formula weight

Add CaO having under the pressurized air stirring condition, stir after 15 minutes by water pump finished product CaCl ₂Solution is delivered to agglomerate belt top and sprays.

Facts have proved: this utilizes the sintering flue gas desulfurization method of wastewater treatment not only to finish the processing of waste water, and when producing sprinkling agglomerate usefulness CaCl2 solution, has also obtained gypsum (CaSO ₄2H ₂O) therefore byproduct achieves many things at one stroke, practical, very scientific and reasonable.

In addition to the implementation, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of requirement of the present invention.

Claims

1. a sintering flue gas desulfurization wastewater treatment utilizes the specific equipment of method, said method comprising the steps of:

The SO in the wastewater supernatant fluid is drawn in second step, detection ₄ ^2-Concentration adds the unslaked lime of respective amount, makes it fully following chemical reaction to take place, and removes the SO in the wastewater supernatant fluid ₄ ^2-

CaO+3H ₂O+SO ₄ ^2-→CaSO ₄·2H ₂O↓+2OH ^-

The C1 in the intermediate liquid supernatant liquor is drawn in the 4th step, detection ^-Concentration adds the unslaked lime of respective amount, and feeds the pressurized air stirring, is made into the CaCl of desired concn ₂Solution;

The 5th the step, with the CaCl that is made into ₂Solution is carried and is sprayed onto on the agglomerate;

It is characterized in that: described equipment comprises Buffer Pool, settling bowl and finished product pond; Described Buffer Pool is used to collect and contains C1 ^-, SO ₄ ^2-Sintering flue gas desulfurization waste water, and after making it clarification; The overflow port of described Buffer Pool leads to settling bowl, is used for wastewater supernatant fluid is drawn out to settling bowl; Described settling bowl is used to collect wastewater supernatant fluid, and removes the SO in the wastewater supernatant fluid behind the unslaked lime to be added ₄ ^2-, generate intermediate liquid; The overflow port of described settling bowl leads to the finished product pond, is used for the supernatant liquor of intermediate liquid is drawn out to the finished product pond; Described finished product pond is used to collect the intermediate liquid supernatant liquor, and unslaked lime to be added, feeds pressurized air and stirs, and is made into the CaCl of desired concn ₂Solution; Described finished product pond leads to agglomerate through transfer line, is used for the CaCl that will be made into ₂Solution is carried and is sprayed onto on the agglomerate.

2. described sintering flue gas desulfurization wastewater treatment utilizes the specific equipment of method according to claim 1, it is characterized in that: the bottom of described settling bowl also leads to dewatering unit by slush pump, is used for that aqueous gypsum is transported to dewatering unit and dewaters.

3. described sintering flue gas desulfurization wastewater treatment utilizes the specific equipment of method according to claim 2, it is characterized in that: described settling bowl constitutes by parallel two groups, uses in turn.