CN111072249A - Sludge drying treatment device and drying method - Google Patents

Abstract

The utility model provides a sludge drying processing apparatus and mummification method, relate to mummification technical field, concretely relates to sludge drying processing technology, the ozone advanced oxidation method of taking adapts to wider pH value scope than the Fenton advanced oxidation method, can not introduce extra iron mud simultaneously, anhydrite that contains in the circulating fluidized bed boiler desulfurization lime-ash meets water and generates dihydrate gypsum, meet water and generate dihydrate gypsum, participate in reconstructing new skeleton, dihydrate gypsum etc. has aroused the volcanic ash activity of circulating fluidized bed boiler desulfurization lime-ash, make active silicon, aluminium dissolve out, take place the volcanic ash reaction, participate in reconstructing new skeleton on the one hand, the dewatering performance of mud has been improved, on the other hand can stabilize heavy metal material.

Description

Sludge drying treatment device and drying method

Technical Field

The invention relates to the technical field of drying, in particular to a sludge drying treatment technology.

Background

Sludge is a general term for precipitates, particles and floating materials generated when wastewater is treated by physical, chemical, physicochemical and biological methods. The sludge contains a large amount of toxic and harmful substances such as organic matters, pathogens, heavy metals and the like, and the sludge occupies huge volume due to the characteristic of extremely high water content. Therefore, sludge reduction is a focus problem in the current environmental engineering community.

The inherent characteristics of sludge cause sludge particles to form a network structure near the filter medium, thus preventing the sludge from settling and compressing, while the increasingly developed water treatment technology causes the sludge to be complicated, so that the sludge dewatering reduction is more difficult. At the same time, governments set more strict local standards in consideration of energy conservation and comprehensive utilization of dewatered sludge, so that various scholars are dedicated to developing more scientific sludge drying methods.

At present, chemical conditioning measures are generally needed to improve the sludge dewatering performance in order to effectively dewater sludge. The more common chemical conditioning method is to add coagulant or flocculant (such as lime, polyaluminium chloride and polyacrylamide) and to add inert coagulant aid (such as pulverized coal furnace fly ash). However, the above conditioning method only has a significant improvement effect on the removal of free water, and the effect on the bound water is not obvious. Therefore, by adding the conditioner and then mechanically dehydrating, the water content of the dehydrated sludge is only 70-85%, and the water content is difficult to further reduce.

In order to further improve the sludge conditioning effect, a fenton oxidation conditioning technology method (for example, patent publication No. CN 102180583A) is adopted to degrade organic matters, dissolve and break polystyrene foam and cell walls, achieve sludge reduction and improve sludge dewatering performance. However, the pH of the sludge needs to be adjusted to about 3, and the whole sludge system is acidic after the reaction is finished, so that secondary pollution is easily caused.

In addition, researchers also devote themselves to improving inert coagulant aids, which not only serve as inert frameworks, but also have the functions of improving conditioning effects and adsorbing pollutants such as organic matters and heavy metals. For example: the invention patent with the patent application publication number of CN105461183A utilizes the modified pulverized coal furnace fly ash loaded with iron and manganese elements to improve the oxidation performance of an oxidant in Fenton reaction and degrade polystyrene foam, thereby improving the dehydration performance of sludge; the invention patent with patent application publication number CN105217905A utilizes sodium hydroxide to modify pulverized coal furnace fly ash, activates silicon-aluminum active ingredients in the fly ash, and simultaneously, the introduction of alkaline groups is more beneficial to the breaking of residual sludge; the invention patent with application publication number CN106622111A adopts an acid modification mode to treat the fly ash of a pulverized coal furnace, so that the capability of stabilizing heavy metals in sludge is enhanced. However, these methods all require treatment of the industrial solid waste coal powder furnace fly ash to make it have corresponding functions, which increases the preparation cost of the medicament.

In view of the above, it is a problem to be solved at present to find an advanced oxidation method with a wider pH adaptation range and a coagulant aid with certain functions without treatment. The invention responds to the increasingly complex sludge dewatering requirement on the basis of the two problems.

Disclosure of Invention

In order to achieve the purpose, the invention discloses a sludge drying treatment device and a drying method.

The technical scheme adopted by the invention is as follows: the utility model provides a sludge drying processing apparatus, includes first recuperating pond and second recuperating pond, first recuperating pond intercommunication second recuperating pond, first recuperating pond is provided with into mud mouth, first recuperating pond leads to there is the first aeration pipe that is used for pouring into ozone, the below of first aeration pipe still is equipped with the second aeration pipe that is used for pouring into the air, the second recuperating pond is provided with the dog-house of the desulfurization lime-ash that carries circulating fluidized bed boiler to produce, be provided with the mixer in the second recuperating pond.

As a further improvement of the invention, the second conditioning pool is also communicated with a high-pressure filter press, and a sludge delivery pump is arranged on a communication path between the second conditioning pool and the high-pressure filter press.

As a further improvement of the invention, the system also comprises a sewage treatment system, wherein the sewage treatment system is communicated with the high-pressure filter press, and the sewage treatment system is also communicated with a low-temperature drying chamber.

As a further improvement of the invention, a crusher for crushing filter-pressed mud blocks is arranged below the high-pressure filter press, and a discharge hole of the crusher is communicated with a feed inlet of the low-temperature drier.

The invention also provides a drying method of the sludge drying treatment device, and the technical scheme is as follows:

the drying method of the sludge drying treatment device comprises the following steps:

s1: mixing sludge to be treated with ozone, and mixing the sludge to be treated mixed with the ozone with desulfurization ash from a circulating fluidized bed boiler to form a sludge mixture;

s2: filter-pressing and dehydrating the sludge mixture to obtain a mud cake;

s3: crushing the mud cake;

s4: and drying the crushed mud cakes to obtain dried sludge.

As a further improvement of the invention, in the step S1, the adding amount of the ozone is 30-100g per 1kg of oven-dried sludge.

As a further improvement of the invention, the addition amount of the desulfurization ash is 50-200g per 1kg of oven-dried sludge.

As a further improvement of the present invention, the pressure filtration conditions in the step S2 are: the mud feeding pressure is 1.0-2.0MPa, the squeezing time is 10-30min, and the squeezing pressure is 8-15 MPa.

As a further improvement of the present invention, in step S4, the drying conditions are: the temperature is 46-50 ℃, and the drying time is 60-180 min.

The invention has the beneficial effects that: compared with the Fenton advanced oxidation method, the ozone advanced oxidation method adopted by the invention is suitable for a wider pH value range, simultaneously, no additional iron mud is introduced, and the desulfurized ash slag generated by the circulating fluidized bed boiler has a coagulation effect and stronger adsorption capacity, so that the sludge with the water content of 85-88.5% is dried until the water content is 30-40%, and the method has the advantages of low energy consumption, low cost and convenient use.

Drawings

The invention is further described with reference to the following figures and embodiments.

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a flow diagram of the drying process of the present invention.

Detailed Description

The sludge drying treatment device shown in fig. 1 comprises a first conditioning tank 1 and a second conditioning tank 2, wherein the first conditioning tank 1 and the second conditioning tank 2 both adopt a sealing structure, the first conditioning tank 1 is communicated with the second conditioning tank 2, the preferable first conditioning tank 1 is communicated with the second conditioning tank 2 at the upper part, the first conditioning tank 1 is further provided with a sludge inlet 3, and the preferable sludge inlet 3 is arranged at the bottom of the side wall of the first conditioning tank 1. The first conditioning tank 1 is communicated with a first aeration pipe 4 for injecting ozone, a second aeration pipe 5 is arranged below the first aeration pipe 4, and the second aeration pipe 5 is used for injecting air. Preferably, the first aeration pipe 4 and the second aeration pipe 5 are arranged at the bottom of the first conditioning pool 1, the second conditioning pool 2 is provided with a feeding pipe 6 for conveying desulfurization ash, and the second conditioning pool 2 is internally provided with a stirrer 7.

In this technical scheme, utilize the aeration effect of first aeration pipe 4 and second aeration pipe 5 for mud can fully mix with ozone at first conditioning tank 1, and input air through second aeration pipe 5 can make the mud in first conditioning tank 1 roll, reach stirring and intensive mixing's effect. In addition, because ozone has stronger corrosivity and oxidizability, conventional carbon steel and stainless steel can not satisfy the requirement of ozone aeration, consequently first aeration pipe 4 adopts the titanium aeration pipe, and second aeration pipe 5 sets up the below at first aeration pipe 4 for ozone overflows upwards, has avoided the contact of second aeration pipe 5 with ozone. The mixer 7 is also used to accelerate the mixing of the sludge with the desulphurised ash.

Further, a tail gas destruction chamber 15 is arranged at the top of the first conditioning pool 1, and the tail gas destruction chamber 15 is communicated with and arranged above the first conditioning pool 1. The tail gas destruction chamber 15 mainly destroys ozone and prevents tail gas from overflowing the first conditioning pool 1.

The second conditioning pool 2 is communicated with a high-pressure filter press 8, and a sludge delivery pump 9 is arranged on a communication path of the second conditioning pool 2 and the high-pressure filter press 8. In the present technical solution, the high-pressure filter press 8 refers to a filter press with a pressing capacity of 1.6Mpa or more, and in this embodiment, the high-pressure filter press 8 is a high-pressure plate-and-frame filter press. The high-pressure filter press 8 realizes the preliminary dehydration of the sludge by pressing the sludge, the water content rate of the sludge after the preliminary dehydration is 40 percent, and compared with the conventional filter pressing, the energy consumption of the subsequent drying can be greatly reduced. The sludge conveying pump 9 adopts a slurry pump to assist the sludge to flow from the second conditioning pool 2 to the high-pressure filter press 8.

In order to avoid the interference of moisture in the filter pressing and drying processes, the device further comprises a sewage treatment system 12, the sewage treatment system 12 is communicated with the high-pressure filter press 8, and the sewage treatment system 12 is further communicated with a low-temperature drying chamber 13. Due to the characteristics of the structure of the high-pressure filter press 8, the filtrate outflow modes are open flow filtration and dark flow filtration, in the open flow filtration, a water nozzle is arranged on a liquid outlet hole below each filter plate, and the filtrate flows out from the water nozzle directly; in the dark current filtration, a liquid outlet channel hole is arranged below each filter plate, liquid outlet holes of a plurality of filter plates are connected into a liquid outlet channel and are discharged by a pipeline connected with the liquid outlet holes below the thrust plate. The sewage treatment system 12 needs to be communicated with a water nozzle or a pipeline to realize the drainage effect. The low-temperature drying chamber 13 is used for drying the sludge after the initial dehydration, further reducing the water content in the sludge, and generating steam inevitably in the drying process, wherein the steam flows along the sewage treatment system 12 and is treated and discharged by final sewage treatment equipment. In this embodiment, the sewage treatment system 12 is a water pipe, and a purification device is disposed at the end of the water pipe. Through mixing and generating action with the desulfurization ash, the main components in the sewage are dust and desulfurization products; containing soluble chlorides and fluorides, nitrates, etc.; and the purification system also comprises heavy metal ions such As Hg, Pb, Ni, As and the like, so that the sewage can be discharged after evolution, and a plurality of purification devices are provided, such As a thermal power plant desulfurization wastewater purification system and a purification method with the patent number of ZL201410416936.2, and other purification devices on the market can be adopted.

The caking phenomenon of the mud blocks after being filter-pressed by the high-pressure filter press 8 is serious, and the whole mud blocks enter the low-temperature drier easily to cause the situations of incapability of filling, nonuniform drying and the like, so that the mud blocks need to be crushed before being filled into the low-temperature drier. In this embodiment, the crusher 10 is disposed below the high-pressure plate-and-frame filter press, so that the mud cake falls into the crusher 10 after the filter press plates of the high-pressure plate-and-frame filter press are separated. The discharge port of the crusher 10 is communicated with the feed port of the low-temperature drier, and the crushed sludge can be conveyed by a conventional way such as a conveyor belt and the like, and is conveyed to the drier for low-temperature drying. Preferably, a transfer bin 11 is further arranged between the high-pressure plate-and-frame filter press and the crusher 10, the transfer bin 11 is used for temporarily storing mud blocks, and incomplete crushing caused by excessive mud blocks is avoided.

The device can also be additionally provided with a control system 14 with logic operation capability, such as a PLC (programmable logic controller), and the like, so as to realize automatic control of each component. The device dries the sludge with the water content of 85-88.5% to the water content of 30-40%, and has the advantages of low energy consumption, low cost and convenient use.

As shown in fig. 2, the invention further provides a drying method using the sludge drying treatment device, which comprises the following steps: s1: mixing the treated sludge with ozone in a first conditioning tank 1 and then with desulfurized ash in a second conditioning tank 2 to form a sludge mixture; s2: filter-pressing and dehydrating the sludge mixture to obtain a mud cake; s3: crushing the mud cake; s4: and drying the crushed mud cakes to obtain dried sludge.

In the technical scheme, the desulfurized ash comes from powder collected by the flue gas of the circulating fluidized bed boiler and/or bottom slag after combustion of the circulating fluidized bed boiler. In the technical scheme, the adopted ozone advanced oxidation method is adaptive to a wider pH value range than a Fenton advanced oxidation method, and meanwhile, additional iron mud is not introduced. And the desulfurized ash residue is used as a coagulant aid, and the functional requirements of the modified fly ash can be met without modification. Specifically, different from free calcium oxide in coal ash of a pulverized coal furnace, activated calcium oxide is contained in desulfurization ash of a circulating fluidized bed boiler, and the desulfurization ash can react with water to form calcium hydroxide, which is equivalent to the coagulation effect of lime; secondly, the desulfurization ash of the circulating fluidized bed boiler has higher specific surface area and stronger adsorption capacity than the pulverized fuel ash of the pulverized coal furnace; thirdly, anhydrite contained in the desulfurization ash of the circulating fluidized bed boiler generates dihydrate gypsum when meeting water and participates in reconstructing a new skeleton, so that the new skeleton form substances are uniformly distributed in the sludge, and the porosity of the sludge is obviously increased; and finally, calcium hydroxide and dihydrate gypsum formed in water excite the volcanic ash activity of the desulfurization ash of the circulating fluidized bed boiler, so that active silicon and aluminum are dissolved out to generate a volcanic ash reaction, on one hand, the calcium hydroxide and the dihydrate gypsum participate in reconstructing a new framework, the dehydration performance of sludge is improved, and on the other hand, heavy metal substances can be stabilized.

In a further improved technical scheme, in the step S1, 30-100g of ozone is added to every 1kg of oven-dried sludge. The addition amount of ozone is small, and the stirring effect cannot be achieved, so that air can be added in an auxiliary manner, and the addition amount of the air is 0.02-0.06m3 air/(m 3 pool volume/min). The tank volume here refers to the volume of the first conditioning tank 1.

In step S2, the filter pressing conditions are: the mud feeding pressure is 1.0-2.0Mpa, the squeezing time is 10-30min, and the squeezing pressure is 8-15 Mpa.

In step S4, the drying conditions are: the temperature is 46-50 ℃, and the drying time is 60-180 min.

The sludge drying treatment method is illustrated by three examples as follows:

example 1:

conveying sludge in a dewatering room of a certain municipal sewage treatment plant to a first conditioning tank 1 with the water content of 85%, and then adding 86g of ozone/kg of oven-dried sludge for reaction for 30 min; then adding 110g of circulating fluidized bed boiler desulfurization fly ash/kg of oven-dried sludge, and stirring for reaction for 10 min; then conveying the conditioned sludge to a high-pressure filter press 8, wherein the sludge feeding time is 20min, the sludge feeding pressure is 1.2MPa, the squeezing time is 25min, the squeezing pressure is 8MPa, and the discharging time is 10min, so that a sludge cake with the water content of 43% is formed; and (3) uniformly adding the sludge cakes with the water content of 40% after being crushed by the transfer bin and the crusher 10 into a low-temperature heat drying chamber, drying at the temperature of 50 ℃ for 110min to form dried sludge with the water content of 30%, wherein the treated dried sludge can be used as a raw material of cement or a raw material of a building material product.

Example 2: conveying dewatered sludge of an industrial sewage treatment plant to a first conditioning tank 1, adding 65g of ozone/kg of oven-dried sludge, and reacting for 60min, wherein the water content of the dewatered sludge is 88%; adding 150g of desulfurization bottom slag of the circulating fluidized bed boiler/kg of oven-dried sludge, and stirring for reaction for 10 min; conveying the conditioned sludge to a high-pressure filter press 8, wherein the sludge feeding time is 25min, the sludge feeding pressure is 1.5MPa, the squeezing time is 20min, the squeezing pressure is 12MPa, and the discharging time is 10min, so that a sludge cake with the water content of 45% is formed; and (3) uniformly adding the mud cakes with the water content of 45% after being crushed by a transfer bin and a crusher 10 into a low-temperature heat drying chamber, drying at 45 ℃ for 150min to form dried sludge with the water content of 38%, wherein the treated dried sludge can be used as a raw material of cement raw materials or building material products.

Example 3:

the method comprises the following steps of conveying dewatered sludge containing heavy metals in an industrial sewage treatment plant to a first conditioning tank 1, adding 65g of ozone/kg of oven-dried sludge, and reacting for 50 min; adding 80g of circulating fluidized bed boiler desulfurization bottom slag/kg of oven-dried sludge and 80g of circulating fluidized bed boiler desulfurization fly ash/kg of oven-dried sludge, and stirring for reaction for 10 min; then conveying the conditioned sludge to a high-pressure filter press 8 for 25min, wherein the sludge feeding pressure is 1.5MPa, the squeezing time is 20min, the squeezing pressure is 12MPa, and the discharging time is 10min, so as to form a sludge cake with the water content of 40%; and (3) uniformly adding the sludge cakes with the water content of 40% after being crushed by the transfer bin and the crusher 10 into a low-temperature heat drying chamber, drying at 50 ℃ for 60min to form dried sludge with the water content of 35%, wherein the treated dried sludge can be used as a raw material of cement raw materials or building material products.

The above description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention.

Claims (9)

1. A sludge drying treatment device is characterized in that: including first recuperating pond (1) and second recuperating pond (2), first recuperating pond (1) intercommunication second recuperating pond (2), first recuperating pond (1) is provided with into mud mouth (3), first recuperating pond (1) leads to there is first aeration pipe (4) that is used for pouring into ozone, the below of first aeration pipe (4) still is equipped with second aeration pipe (5) that are used for pouring into the air, second recuperating pond (2) are provided with dog-house (6) of the desulfurization lime-ash that carry circulating fluidized bed boiler to produce, be provided with mixer (7) in second recuperating pond (2).

2. The sludge drying treatment device according to claim 1, characterized in that: the second conditioning pool (2) is also communicated with a high-pressure filter press (8), and a sludge delivery pump (9) is arranged on a communication path between the second conditioning pool (2) and the high-pressure filter press (8).

3. The sludge drying treatment device according to claim 2, characterized in that: the device is characterized by further comprising a sewage treatment system (12), wherein the sewage treatment system (12) is communicated with the high-pressure filter press (8), and the sewage treatment system (12) is further communicated with a low-temperature drying chamber (13).

4. The sludge drying treatment device according to claim 3, characterized in that: the lower part of the high-pressure filter press (8) is provided with a crusher (10) for crushing filter-pressed mud blocks, and a discharge hole of the crusher (10) is communicated with a feed inlet of the low-temperature drier.

5. The drying method of the sludge drying treatment device based on any one of claims 1 to 4, which is characterized in that: the method comprises the following steps:

s1: mixing sludge to be treated with ozone, and mixing the sludge to be treated mixed with the ozone with desulfurization ash from a circulating fluidized bed boiler to form a sludge mixture;

s2: filter-pressing and dehydrating the sludge mixture to obtain a mud cake;

s3: crushing the mud cake;

s4: and drying the crushed mud cakes to obtain dried sludge.

6. The drying method of the sludge drying treatment device according to claim 5, characterized in that: in the step S1, the adding amount of ozone is 30-100g per 1kg of oven-dried sludge.

7. The drying method of the sludge drying treatment device according to claim 5, characterized in that: the addition amount of the desulfurization ash is 50-200g per 1kg of oven-dried sludge.

8. The drying method of the sludge drying treatment device according to claim 5, characterized in that: the filter pressing conditions in the step S2 are as follows: the mud feeding pressure is 1.0-2.0MPa, the squeezing time is 10-30min, and the squeezing pressure is 8-15 MPa.

9. The drying method of the sludge drying treatment device according to claim 5, characterized in that: in step S4, the drying conditions are as follows: the temperature is 46-50 ℃, and the drying time is 60-180 min.

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