CN212713214U - Sludge drying treatment equipment - Google Patents

Abstract

The utility model relates to a sludge drying treatment device, which comprises a sludge dryer, a sludge drying device and a sludge drying device, wherein the sludge dryer is used for drying sludge to be treated so as to obtain dry sludge and waste gas; the boiler comprises a primary/secondary boiler air pipe, a hearth, an air preheater, a tail flue and a first dust remover, a sludge dryer and the primary/secondary boiler air pipe, so that the waste gas is introduced into the hearth from the primary/secondary boiler air pipe, and the air preheater and the first dust remover are sequentially arranged on the tail flue; the first heat exchanger is arranged in the tail flue and is positioned between the air preheater and the first dust remover; and the fresh air heater is connected with the sludge drying machine and is used for heating fresh air and providing heated fresh air for the sludge drying machine, and the first heat exchanger is connected with the fresh air heater and is used for providing heat required by the heating fresh air for the fresh air heater. The sludge drying treatment equipment carries out drying treatment on sludge by using the waste heat of the flue gas at the outlet of the air preheater of the tail flue of the boiler, and the waste gas treatment is thorough and pollution-free.

Description

Sludge drying treatment equipment

Technical Field

The utility model relates to a sludge treatment technical field especially relates to a sludge drying treatment facility.

Background

The municipal sludge refers to sludge produced after water quality purification in urban sewage treatment plants, and also comprises sludge produced in water works, drainage pipe networks and urban water body dredging. The municipal sludge has extremely high water content, is black brown or dark brown pasty substance, has high organic matter content, is easy to rot, has foul smell, contains various microorganisms such as parasitic ova and pathogens, is rich in heavy metal, has a great amount of other refractory toxic and harmful substances such as inorganic salt, polychlorinated biphenyl, dioxin and the like, and can cause serious pollution and secondary pollution if not treated.

The components of the sludge are complex, but the application effect of the conventional disposal methods such as sanitary landfill, agricultural utilization, building material utilization and the like is not good enough at present, and serious secondary pollution and potential safety hazard exist. At present, the sludge drying is mostly applied in a mechanical dehydration mode and a thermal dehydration mode. The mechanical dehydration mode of the sludge mainly comprises centrifugal dehydration, vacuum filtration dehydration, plate-frame filter-pressing dehydration, belt filter-pressing dehydration and the like; the mechanical dehydration needs to add a large amount of conditioners rich in sulfate ions, chloride ions and the like, the dehydration rate is limited, the highest dehydration rate can only be 55 percent at present, and the addition of the conditioners can increase the treatment cost, bring secondary pollution and bring great troubles to subsequent treatment. The thermal dehydration method is a technology for drying and deeply dehydrating sludge by using heat, but a large amount of waste gas and waste water are generated in the drying process, so that the problems of high difficulty in waste gas treatment, low efficiency and high operation cost are caused.

SUMMERY OF THE UTILITY MODEL

Therefore, the sludge drying treatment equipment which does not need to add a medicament, has no waste gas and zero emission and is low in operation cost is needed.

A sludge drying treatment device comprises:

a sludge dryer for drying sludge to be treated to obtain dry sludge and waste gas;

the sludge dryer is connected with the primary/secondary air pipe of the boiler so as to introduce the waste gas into the hearth from the primary/secondary air pipe of the boiler, and the air preheater and the first dust remover are sequentially arranged on the tail flue;

the first heat exchanger is arranged in the tail flue and is positioned between the air preheater and the first dust remover; and

the fresh air heater is connected with the sludge drying machine and used for heating fresh air and supplying the heated fresh air to the sludge drying machine, and the first heat exchanger is connected with the fresh air heater and used for supplying heat required by the heated fresh air to the fresh air heater.

When the sludge drying treatment equipment works, sludge to be treated enters a sludge dryer for drying, and dried waste gas enters a hearth for combustion through a primary air pipe/a secondary air pipe of a boiler to remove organic matters in the waste gas; the first heat exchanger provides the heat of the flue gas at the outlet of the air preheater of the boiler to the fresh air heater, the fresh air heater is used for heating fresh air, and the heated fresh air is taken as a drying medium and is conveyed to the sludge dryer to be used for drying sludge; therefore, waste heat of the tail flue of the boiler is used for carrying out thermal drying treatment on the sludge, conditioners rich in sulfate ions, chloride ions and the like are not required to be added, and the waste gas is introduced into the hearth for combustion, so that the treatment is thorough and pollution-free, the whole equipment has no waste gas and zero emission, and the operation cost is low.

In some embodiments, the sludge drying treatment equipment further comprises a second dust remover, the second dust remover is a constant temperature dust remover, the air inlet end of the second dust remover is connected with the sludge dryer, and the air outlet end of the second dust remover is connected with the primary/secondary air pipe of the boiler.

In some of these embodiments, the first heat exchanger is also connected to the second dust separator and is used to provide heat to the second dust separator.

In some of these embodiments, the dust outlet of the second precipitator is connected to the sludge dryer to return dust collected by the second precipitator to the sludge dryer.

In some embodiments, the sludge drying treatment equipment further comprises a first condenser and a first demister, wherein the first condenser is arranged between the second dust remover and the first/second air pipe of the boiler, and the first demister is arranged between the first condenser and the first/second air pipe of the boiler.

In some embodiments, the sludge drying treatment equipment further comprises a second condenser and a second demister, wherein the second condenser is arranged between the first demister and the first/second air pipe of the boiler, and the second demister is arranged between the second condenser and the first/second air pipe of the boiler.

In some embodiments, the sludge drying treatment equipment further comprises a first cooling device and a second cooling device, wherein the first cooling device is connected with the first condenser and is used for providing condensed water required by the first condenser, and the second cooling device is connected with the second condenser and is used for providing chilled water required by the second condenser;

the first cooling device is a cooling tower, and the second cooling device is an air-cooled heat pump water chilling unit; the second cooling device is also connected with the fresh air heater and is used for absorbing latent heat of condensed water and utilizing the latent heat to preheat fresh air.

In some embodiments, the sludge drying treatment equipment further comprises an exhaust gas reheater, and the exhaust gas reheater is arranged between the second demister and the primary/secondary air pipe of the boiler.

In some of these embodiments, the first heat exchanger is also connected to the exhaust gas reheater and is used to provide the exhaust gas reheater with the heat required to heat the exhaust gas.

In some embodiments, the sludge drying treatment equipment further comprises a booster fan, and the booster fan is arranged between the second demister and the waste gas reheater.

In some embodiments, the sludge drying treatment equipment further comprises a sludge negative pressure bin, a screw conveying pump and a sludge former which are sequentially connected, and the sludge former is connected with the sludge dryer.

In some embodiments, the sludge drying treatment equipment further comprises a dry sludge bin, the dry sludge bin is connected with the sludge dryer, and the dry sludge bin is further connected with the screw conveying pump.

In some embodiments, the sludge drying treatment equipment further comprises an incinerator connected with the sludge dryer and used for incinerating the dry sludge from the sludge dryer.

Drawings

FIG. 1 is a schematic structural view of a sludge drying treatment apparatus according to an embodiment;

FIG. 2 is a diagram showing a dried sludge produced by the sludge drying treatment apparatus shown in FIG. 1 in a sludge drying machine by hot air at 85-90 ℃.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. The preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The skilled person finds that the sludge has a high organic content and a high dry basis calorific value (on average above 10000 kJ/kg), and it is feasible to utilize the sludge as energy source, i.e. to incinerate the sludge, wherein the volume of the sludge can be reduced to a minimum during the incineration process, and the calorific value can also be partially recovered. However, most of the sludge contains a large amount of dioxin, salt (mainly chloride ions) and the like, so that the treatment of the dioxin and the chloride ions is not considered in the sludge incineration modes such as the main mechanical dehydration and heat drying reduction treatment, the cement and industrial kiln collaborative incineration, the industrial boiler or power station boiler coal blending incineration and the like, and a lot of problems are caused. For example, sludge ash can degrade cement quality, resulting in reduced grade; the low-temperature corrosion of the tail flue of the boiler is aggravated; dioxin in the discharged flue gas exceeds the standard. Therefore, in practice, the threshold for energy utilization of sludge is actually quite high, and a professional incinerator or a garbage incinerator is required. For this type of incinerator, maintaining the stability of the incineration process is a critical point. The self-sustaining incineration of sludge generally needs to reduce the water content to 58.67% (heat value > 3350kJ/kg), and to realize heat recovery, the water content needs to be reduced to 49.48% (heat value > 4600 kJ/kg). Therefore, the key of sludge treatment and disposal is to remove moisture, which is a main way for realizing sludge reduction and is also an important step for realizing sludge stabilization, harmlessness and recycling.

As described in the background art, the mechanical sludge dewatering modes mainly include centrifugal dewatering, vacuum filtration dewatering, plate-and-frame filter-press dewatering, belt-type filter-press dewatering and the like; the mechanical dehydration needs to add a large amount of conditioners rich in sulfate ions, chloride ions and the like, the dehydration rate is limited, the highest dehydration rate can only be 55 percent at present, and the addition of the conditioners can increase the treatment cost, bring secondary pollution and bring great troubles to subsequent treatment. The thermal dehydration method is a technology for drying and deeply dehydrating the sludge by using heat, but a large amount of waste gas and waste water are generated in the drying process, so that the waste gas treatment difficulty is high, the efficiency is low and the operation cost is high.

Specifically, the thermal dehydration method can be divided into high-temperature drying (more than 150 ℃) and low-temperature drying (within 100 ℃) according to the temperature. High-temperature drying needs to consume high-grade energy sources such as raw steam, natural gas, diesel oil and the like, generally adopts dryers such as a rotary drum type dryer, a rotary disc type dryer, a fluidized bed dryer and the like, and drying media are air, fuel gas, steam or hot oil, so that the energy consumption and the operating cost of a system are high; because the operating condition temperature is high and the operating condition is complex, the requirements on the manufacturing precision and the material of the equipment are also high; the high-temperature drying can cause the loss of volatile organic compounds such as alkanes, aromatic hydrocarbons, lipids and the like in the sludge, thereby reducing the heat value of the sludge, leading the components of the generated waste water and waste gas to be complex, and greatly increasing the environmental protection investment and the treatment cost; in addition, because the drying temperature is high, more organic waste gas is generated in the drying process, and potential safety hazards such as dust explosion, spontaneous combustion and the like exist.

Low-temperature drying generally utilizes low-grade energy sources such as solar energy and waste heat or a heat pump drying technology, and although unit energy consumption is increased, operation cost may be reduced, and loss of volatile organic compounds is reduced. However, a large amount of waste gas and waste water still generated in the drying process cause great difficulty in waste gas treatment, low efficiency, higher initial investment, complex process and higher operation and maintenance cost.

Referring to fig. 1, based on the above, an embodiment of the present invention provides a sludge drying treatment apparatus, which includes a sludge dryer 114, a boiler, a first heat exchanger 127, and a fresh air heater 116.

The sludge dryer 114 is used to dry sludge to be treated to obtain dry sludge and waste gas.

The boiler comprises a primary/secondary air pipe of the boiler, a tail flue, an air preheater and a first dust remover. The sludge dryer 114 is connected with the primary/secondary air pipe of the boiler to introduce the waste gas from the primary/secondary air pipe of the boiler into the hearth for combustion, and the air preheater and the first dust remover are sequentially arranged on the tail flue. That is, the air preheater and the first dust remover are sequentially arranged in the exhaust direction on the tail flue, in other words, the first dust remover is closer to the exhaust port of the tail flue than the air preheater. The primary/secondary air pipes of the boiler include a primary air pipe and a secondary air pipe of the boiler, and specifically, the sludge dryer 114 is connected to the primary air pipe and/or the secondary air pipe of the primary/secondary air pipes of the boiler.

The first heat exchanger 127 is arranged in the tail flue and is positioned between the air preheater and the first dust remover. The fresh air heater 116 is connected to the sludge dryer 114 and is used for heating fresh air and providing the heated fresh air to the sludge dryer 114. The first heat exchanger 127 is connected with the fresh air heater 116 and is used for providing heat required by heating fresh air for the fresh air heater 116.

When the sludge drying treatment equipment works, sludge to be treated firstly enters the sludge dryer 114 for drying, and dried waste gas enters the hearth through the primary air pipe/the secondary air pipe of the boiler for combustion to remove organic matters in the waste gas; the first heat exchanger 127 provides the heat of the flue gas at the outlet of the boiler air preheater to the fresh air heater 116, and is used for heating fresh air in the fresh air heater 116, and the heated fresh air is taken as a drying medium and is conveyed to the sludge dryer 114 for drying sludge; therefore, waste heat of the tail flue of the boiler is utilized to carry out drying treatment on the sludge in a thermal dehydration mode, conditioners rich in sulfate ions, chloride ions and the like are not required to be added, and the waste gas is introduced into the hearth for combustion, so that the treatment is thorough and pollution-free, the whole equipment has no waste gas zero emission, and the operation cost is low.

It can be understood that, generally, the smoke temperature at the outlet of the air preheater is 120-150 ℃, and the temperature between the smoke and the smoke entering the first dust remover is lower than the temperature and generally higher than 105 ℃, so the heating temperature range of the first heat exchanger 127 is also in the range; in other words, the heat provided by the fresh air heater 116 promotes the sludge drying of the sludge dryer 114 to be in a low-temperature sludge drying mode, the process has less organic matter loss and stable sludge heat value, and is beneficial to sludge incineration.

In addition, the sludge drying treatment utilizes low-temperature waste heat of the flue gas at the outlet of the boiler air preheater, so that the drying temperature of the sludge dryer is low, chloride ions are not converted into hydrogen chloride and enter waste gas, but are completely remained in dry sludge, and the dry sludge can be subsequently transferred to a special sludge or garbage incinerator for incineration.

It is understood that the sludge drying treatment preferably uses the heat provided by the first heat exchanger 127, but not limited thereto, and other heat sources such as steam can be provided as backup heat sources, on one hand, the treatment capacity of the sludge can be doubled by using other heat sources such as steam as heat sources, on the other hand, the other equipment structure is basically not required to be changed, so as to deal with the sudden sludge amount burst.

In some of these embodiments, the sludge drying treatment apparatus further comprises an incinerator connected to the sludge dryer 114 for incinerating the dry sludge from the sludge dryer 114.

In some embodiments, the sludge drying treatment equipment further comprises a sludge negative pressure bin 111, a screw conveying pump 112 and a sludge former 113 which are connected in sequence; the sludge former 113 is connected to the sludge dryer 114.

Further, the screw transfer pump 112 and the sludge former 113 are communicated with each other through the sludge transfer pipe 21. The sludge to be treated by the municipal sludge is transported to a sludge negative pressure bin 111 for storage, and is conveyed to a sludge former 113 along a sludge conveying pipe 21 through a screw conveying pump 112; the sludge former 113 processes the sludge into fine particles (e.g., < 25mm) by cutting, extruding, etc., and then sends the fine particles to the sludge dryer 114 for low-temperature drying. Further, the sludge dryer 114 is preferably a belt dryer; it is understood that other types such as fluidized bed, conveyor, etc. may be used. Further, the corrosion resistance of the flow-through material in the sludge dryer 114 is not lower than that of 316L stainless steel.

Further, the sludge drying treatment equipment further comprises a dry sludge bin 115, and the dry sludge bin 115 is connected with the sludge dryer 114 and is used for storing the dry sludge from the sludge dryer 114. Further, the dry sludge bin 115 is also connected with the screw conveying pump 112, so that the sludge which does not reach the drying requirement in the dry sludge bin 115 can further enter the sludge former 113 and the sludge dryer 114 through the screw conveying pump 112 for forming and drying again.

Further, the sludge drying treatment equipment further comprises a dried sludge conveying mechanism 61 and a dried sludge discharge pipe 22, wherein the dried sludge discharge pipe 22 is arranged between the sludge dryer 114 and the dried sludge bin 115, and the dried sludge conveying mechanism 61 is arranged on the dried sludge discharge pipe 22. Specifically, the dried sludge conveying mechanism 61 may be a fan or a screw conveyor, preferably a fan. Specifically, the dry sludge bin 115 is in a micro-negative pressure state; the sludge dryer 114 is also in a slightly negative pressure state.

Further, the dry sludge bin 115 is further connected to a dry sludge discharge pipe 23, so that after the sludge is dried to a set value, the dried sludge is pressurized by the dried sludge conveying mechanism 61, discharged to the dry sludge bin 115 along the dry sludge discharge pipe 222, discharged through the dry sludge discharge pipe 23, and transported to an incinerator such as a sludge incinerator or a garbage incinerator for incineration.

In some of these embodiments, the first heat exchanger 127 is a gas-water heat exchanger. Furthermore, the sludge drying treatment equipment further comprises a fresh air heater water supply pipe 418 and a fresh air heater water return pipe 419, wherein the fresh air heater water supply pipe 418 and the fresh air heater water return pipe 419 are connected between the fresh air heater 116 and the first heat exchanger 127 to form a fresh air heating water circulation pipeline. Specifically, the fresh air heater water supply pipe 418 is provided with an adjusting valve (not shown).

In some of these embodiments, the sludge drying treatment apparatus further comprises a second dust separator 117. The air inlet end of the second dust remover 117 is connected with the sludge dryer 114, and the air outlet end of the second dust remover 117 is connected with the primary/secondary air pipe of the boiler.

Further, the second dust remover 117 is a constant temperature dust remover, and the first heat exchanger 127 is also connected with the second dust remover 117 and is used for providing heat for the second dust remover 117 so as to keep the second dust remover 117 in a constant temperature state. The second dust remover 117 is heated by waste heat of a tail flue generated by boiler combustion, and is preferably kept at a constant temperature (equal to or more than 80 ℃), because the humidity of waste gas is high, the second dust remover 117 needs to maintain a higher temperature, bag pasting and dust accumulation in the dust remover are avoided, and the dust removing effect is improved.

Specifically, the second dust collector 117 is a heat tracing dust collector, that is, a heat tracing device is arranged in the second dust collector 117, so that the temperature of the second dust collector 117 can be maintained by the heat tracing device arranged in the second dust collector 117, and the temperature of the exhaust gas in the second dust collector 117 can be increased, thereby improving the dust removing effect. For example, the heat tracing device can be a tubular heat exchanger or an electric heating heat tracing device, etc.

Further, the type of the second dust collector 117 is not limited, and a bag type dust collector is preferable.

Further, the second dust collector 117 is a heat-tracing dust collector; the sludge drying treatment equipment further comprises a heat tracing water supply pipe 420 and a heat tracing return pipe 421, wherein the heat tracing water supply pipe 420 and the heat tracing return pipe 421 are connected between the second dust remover 117 and the first heat exchanger 127 to form a heat tracing heating water circulation pipeline. Specifically, the adjusting valve (not shown) is disposed on the water supply pipe 420 of the heat tracing apparatus.

Further, a dust outlet of the second dust collector 117 is connected to the sludge dryer 114 to return the dust collected by the second dust collector 117 to the sludge dryer 114 for drying process again. Further, the dust outlet of the second dust collector 117 communicates with the sludge dryer 114 through the dust recovery pipe 33.

Further, the sludge drying treatment equipment further comprises a hot air circulating pipe 31, and two ends of the hot air circulating pipe 31 are connected to an air outlet and an air inlet of the sludge dryer 114, so that hot air of the sludge dryer 114 can be recycled through the hot air circulating pipe 31. Specifically, the hot air circulation pipe 31 is combined with the dust recovery pipe 33 at an end near the air outlet of the sludge dryer 114 to return the dust in the dust recovery pipe 33 into the sludge dryer 114. Further, a booster fan (not shown) may be provided on the dust recycling pipe 33 to discharge the dust collected by the dust collector into the sludge dryer 114.

In some embodiments, the sludge drying treatment apparatus further comprises a first condenser 118 and a first demister 119, wherein the first condenser 118 is disposed between the second dust remover 117 and the first/second air pipe of the boiler, and the first demister 119 is disposed between the first condenser 117 and the first/second air pipe of the boiler. After the second dust remover 117 removes dust from the dust-containing high-temperature and high-humidity exhaust gas formed by the sludge dryer 114 after drying sludge, the exhaust gas is condensed by the first condenser 118 and dehumidified at a low temperature by the first demister 119, so that low-temperature saturated exhaust gas is obtained.

Specifically, the first condenser 118 is a shell and tube heat exchanger, preferably an aluminum fin radiator; the first mist eliminator 119 is preferably a wire mist eliminator.

Further, the sludge drying treatment device further comprises a first cooling device 120, and the first cooling device 120 is connected with the first condenser 118 and is used for providing condensed water for the first condenser 118. In a specific example, the first cooling device 120 is a cooling tower that circulates and cools the condensed water.

Specifically, a condensed water feed pipe 411 and condensed water 412 are provided between the first cooling device 120 and the first condenser 118 to constitute a condensed water circulation line. Furthermore, a condensate circulating pump 51 is disposed on the condensate water supply pipe 411, so that the condensate water cooled by the cooling tower is pressurized by the condensate circulating pump 51 along the condensate water supply pipe 411, sent to the first condenser 118 to cool the exhaust gas, and then returned to the cooling tower through a condensate water return pipe 412.

More specifically, the condenser further includes a primary condensate discharge pipe 413 and a primary condensate tank 121, wherein one end of the primary condensate discharge pipe 413 is connected to the first condenser, and the other end is connected to the primary condensate tank 121. The condensed water separated out from the first condenser 118 is discharged to the primary condensed water tank 121 through the primary condensed water discharge pipe 413, and the water can be directly reused.

Further, the sludge drying treatment equipment further comprises a second condenser 122 and a second demister 123, wherein the second condenser 122 is arranged between the first demister 119 and the first/second air pipe of the boiler, and the second demister 123 is arranged between the second condenser 122 and the first/second air pipe of the boiler.

So through two condenser two-stage condensation and two defroster two-stage defogging to be convenient for waste gas gets into furnace and fully burns.

Specifically, the second condenser 122 is a shell and tube heat exchanger, preferably an aluminum fin radiator; the second mist eliminator 123 is preferably a wire mist eliminator.

Further, a second dust collector 117, a first condenser 118 and a first demister 119, and a second condenser 122 and a second demister 123 are provided in this order downstream of the sludge dryer 114; specifically, a second dust collector 117, a first condenser 118 and a first demister 119, and a second condenser 122 and a second demister 123 are provided in this order on the exhaust gas discharge pipe 32 communicating with the sludge dryer 114. The high-temperature and high-humidity dust-containing exhaust gas formed by drying the sludge in the sludge dryer 114 passes through the second dust collector 117, the first condenser 118 and the first demister 119, and the second condenser 122 and the second demister 123 in this order, and is discharged through the exhaust gas discharge pipe 32. Further, an exhaust check valve 81 and/or an exhaust gas control valve 82 are mounted on the exhaust gas discharge pipe 32. Specifically, an exhaust gas check valve 81 and/or an exhaust gas regulating valve 82 are provided between the sludge dryer 114 and the second precipitator 117 for preventing backflow of the exhaust gas.

Further, the sludge drying treatment device further comprises a second cooling device 124, and the second cooling device 124 is connected with the second condenser 122 and is used for providing chilled water for the second condenser 122.

In one specific example, the second cooling device 124 is an air-cooled heat pump water chiller. Specifically, a secondary condensed water feed pipe 414 and a secondary condensed water return pipe 415 are provided between the second cooling device 124 and the second condenser 122 to constitute a condensed water circulation line. Further, a condensate circulating pump 52 is provided on the secondary condensate water feed pipe 414. The chilled water produced by the second cooling device 124 is pressurized by the condensate circulating pump 52 along the second-stage condensate water supply pipe 414, sent to the second condenser 122 for refrigeration, and then returned to the second cooling device 124 through the second-stage condensate water return pipe 415.

More specifically, a secondary condensate discharge pipe 416 and a secondary condensate tank 125 are further included, and one end of the secondary condensate discharge pipe 416 is connected to the second condenser and the other end is connected to the secondary condensate tank 125. The condensed water from the second condenser 122 is discharged to the condensed water tank 125 through the secondary condensed water discharge pipe 416, and the condensed water can be directly reused.

In a specific example, about 20% of the moisture in the exhaust gas is separated out in the first condenser 118 and the first demister 119, the cooling water used for condensation is cooled by the cooling tower, the condensed water is discharged into the first-stage condensed water tank 121, wherein the content of organic matters is slightly higher, and the condensed water can be directly used for desulfurization make-up water or greening and the like, and can be recycled after being treated by activated carbon adsorption if necessary. The remaining 60% of the water is separated out in the second condenser 122 and the second demister 123, the second condensation is low temperature condensation (less than or equal to 12 ℃), the low temperature chilled water is provided by the second cooling device 124, preferably an air-cooled heat pump unit, and the condensed water is discharged into the second condensed water tank 125. The organic matter content of the part of condensed water is low, and the part of condensed water can be directly used for boiler make-up water, cooling water and the like; two-stage cooling and dehumidification are preferred, so that the energy consumption can be reduced by about 35% and more pure condensed water can be extracted.

Further, the second cooling device 124 is also connected to the fresh air heater 116 and is used for supplying hot air to the fresh air heater 116. The air-cooled heat pump water chiller is used for recovering latent heat of condensed water and preheating fresh air by using the latent heat while cooling the second condenser 122, for example, heating the fresh air to a temperature of more than 45 ℃, and conveying the heated fresh air to the fresh air heater 116 for reheating, and further conveying the heated fresh air to the sludge dryer 114 for sludge drying. Therefore, the fresh air in the fresh air heater 116 is the drying medium of the sludge dryer 114, the hot air provided by the air-cooled heat pump water chilling unit can be used as the source of the drying medium, the fresh air heater 116 is further heated, the waste heat of the air-cooled heat pump water chilling unit is fully utilized, and the comprehensive energy consumption is reduced. Specifically, the drying medium is air, and the amount of the introduced air is determined by the drying requirement of the sludge.

In this particular example, the drying medium consists of two passes. The sludge drying treatment equipment also comprises a fresh air heating pipe 37 connected with the fresh air heater 116, and a heat recovery air pipe 35 and a fresh air supply air pipe 36 which are respectively communicated with the fresh air heating pipe 37; the other end of the heat recovery air pipe 35 is connected with an air-cooled heat pump water chilling unit, and the other end of the fresh air supply air pipe 36 is communicated with the atmosphere. One path of the drying medium is preheated by the air-cooled heat pump water chilling unit and then introduced along the heat recovery air pipe 35, the other path of the drying medium is introduced by the fresh air supply air pipe 36, and the two paths of air are mixed in the fresh air heating pipe 37. Understandably, the drying medium is preferentially introduced by the heat recovery air pipe 35, and when the fresh air is insufficient, the drying medium is simultaneously introduced by the fresh air supply air pipe 36.

Further, a fresh air draught fan 62 is arranged on the fresh air heating pipe 37; further, in order to adjust the air supply amount, a heat recovery air pipe check valve 83 is installed on the heat recovery air pipe 35, and a fresh air supply adjusting valve 84 and a fresh air supply check valve 85 are installed on the fresh air supply air pipe. The two paths of air are mixed in the fresh air heating pipe 37, pressurized by the fresh air draught fan 62, heated to over 75 ℃ in the fresh air heater 116, and conveyed to the sludge dryer 114 to work.

Specifically, the fresh air heater 116 is a gas-water heat exchanger, preferably an aluminum fin radiator. The air duct of the fresh air heater 116 may be made of carbon steel, PVC pipe or glass fiber reinforced plastic, preferably glass fiber reinforced plastic.

In some of the embodiments, the sludge drying treatment apparatus further includes an exhaust gas reheater 126, and the exhaust gas reheater 126 is disposed between the second demister 123 and the primary/secondary air pipe of the boiler.

Further, a booster fan 63 is provided on the exhaust gas discharge pipe 32 between the exhaust gas reheater 126 and the second demister 123. Further, an exhaust gas reheating discharge pipe 34 is arranged between the exhaust gas reheater 126 and the primary/secondary air pipe of the boiler. The low-temperature saturated exhaust gas dehumidified by the second demister 123 is pressurized by the booster fan 63, discharged to the exhaust gas reheater 126, heated, and then discharged to the primary/secondary air duct of the boiler along the exhaust gas reheating discharge pipe 34.

Further, the waste gas is introduced into a primary/secondary air pipe of the boiler and then enters a hearth for combustion. Furthermore, the air guiding pipe can be made of carbon steel, PVC pipe or glass fiber reinforced plastic, and the glass fiber reinforced plastic is preferred.

Further, the first heat exchanger 127 is also connected to the exhaust gas reheater 126 and is used for providing the exhaust gas reheater 126 with heat required for heating the exhaust gas. Therefore, the first heat exchanger 127 utilizes the waste heat of the tail flue in the boiler to simultaneously provide heat for the fresh air heater 116, the second dust remover 117 and the waste gas reheater 126, the waste heat of a power plant and the waste heat of a power boiler are fully utilized, the sludge is dried under the low-temperature working condition, most organic matters are reserved, and the heat value is high and stable. In addition, because the drying temperature is low, the amount of waste gas generated in the drying process is very small, and the drying process is indirect drying without oxygen loss, so that the waste gas is introduced into a hearth for combustion after being dehumidified, and the waste gas condensate can be used as make-up water of a power plant. The sludge drying treatment equipment has the advantages that waste heat is mainly used in the whole drying treatment process, the comprehensive energy consumption of the system is low, the working flexibility is large, zero emission and no secondary pollution are realized in the whole process, the loss of the sludge heat value is less, the waste heat utilization benefit is high, the working temperature is low, and the requirements on system materials and equipment processing precision are low. It will be appreciated that the heat of the exhaust reheater 126 is not limited to the heat provided by the first heat exchanger 127.

Further, the sludge drying treatment equipment further includes a reheater water supply pipe 422 and a reheater water return pipe 423, and the reheater water supply pipe 422 and the reheater water return pipe 423 are both disposed between the exhaust gas reheater 126 and the first heat exchanger 127 to form a reheater water heating circulation pipeline. Specifically, the reheater feedwater pipe 422 is provided with a regulating valve (not shown).

Further, the sludge drying treatment device further comprises a water separator 128 and a water collector 129. The water separator 128 is connected to the water outlet end of the first heat exchanger 127, and one end of the fresh air heater water supply pipe 418, the heat tracing water supply pipe 420, and the reheater water supply pipe 422 are connected to the water separator 128, and the other end thereof is connected to the fresh air heater 116. Further, the water separator 128 is communicated with the first heat exchanger 127 through a heat and water supply main pipe 417; further, a hot water supply circulation pump 53 is also installed in the hot water supply main pipe 417. The water collector 129 is connected with the water inlet end of the first heat exchanger 127, one end of the fresh air heater water supply pipe 418, one end of the heat tracing water supply pipe 420 and one end of the reheater water supply pipe 422 are all connected with the water collector 129, and the other end of the fresh air heater water supply pipe is all connected with the fresh air heater 116.

Thus, in one example, the first heat exchanger 127 absorbs the heat of the flue gas in the tail flue, so that the water in the main heating water supply pipe 417 is heated to above 90 ℃, and after being pressurized by the hot water supply circulating pump 53, the heat is supplied to the fresh air heater 116, the second dust remover 117, the fresh air heater water supply pipe 418, the heat tracing water supply pipe 420, and the reheater water supply pipe 422 along the main heating water supply pipe 417, the water separator 128, the fresh air heater water supply pipe 418, the heat tracing water supply pipe 420, and the reheater water supply pipe 422, respectively, and then the heat is returned to the first heat exchanger 127 along the fresh air heater water return pipe 419, the heat tracing water return pipe 421, the reheater water return pipe 423. It is understood that the heating medium in the hot water supply header 417 is water in this particular example, and may be low pressure steam in other examples.

In summary, the dry sludge produced by the sludge drying treatment device used in one embodiment of sludge treatment is shown in fig. 2, and the sludge drying treatment device has the following advantages: (1) the waste heat of the boiler of the thermal power plant can be used for drying the sludge, the treated waste gas is cooled and dehumidified and then enters the hearth for combustion as primary air or secondary air of the boiler, the waste gas is thoroughly treated without cost, the ultralow emission of the boiler is facilitated, the waste heat utilization rate is high, the added value is large, and the economic benefit is remarkable. (2) The waste gas is cooled and dehumidified by adopting a multi-stage condensation dehumidification mode, so that the energy-saving effect is obvious, and the dehumidification is more thorough; the condensation water with different cleanliness can be obtained by graded dehumidification, the retreatment cost of the condensation water can be saved, and the additional value of the condensation water is improved. (3) The sludge is dried at low temperature, so that the loss of organic matters is less, the heat value of the sludge is stable, and the incineration of the sludge is facilitated. (4) The cooling device adopts an air-cooled heat pump water chilling unit, recovers latent heat in condensed water of the cooling device, is used for supplying fresh air for drying sludge, and has high energy efficiency ratio, obvious environment protection and energy saving effects. (5) The second dust remover adopts a heat tracing type dust remover, so that the dust collection process is always kept at a higher temperature, and bag pasting and dust accumulation in the dust remover are avoided. (6) The system has large production flexibility, can fully or partially use high-grade heat sources such as steam and the like, does not need to change the system, can instantaneously improve the drying strength, has large working flexibility, and can realize the load regulation of 0-200% by only controlling the supply amount of the heating medium. (7) Fresh air is supplied in time for waste gas treatment, so that the content of organic matters in the dryer is low, the system safety is high, and the possibility of spontaneous combustion and explosion is low.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. A sludge drying treatment device is characterized by comprising:

a sludge dryer for drying sludge to be treated to obtain dry sludge and waste gas;

the boiler comprises a primary air pipe, a secondary air pipe, a hearth, an air preheater, a tail flue and a first dust remover, wherein the sludge dryer is connected with the primary air pipe and/or the secondary air pipe so as to introduce the waste gas into the hearth from the primary air pipe and/or the secondary air pipe, and the air preheater and the first dust remover are sequentially arranged on the tail flue;

the first heat exchanger is arranged in the tail flue and is positioned between the air preheater and the first dust remover; and

the fresh air heater is connected with the sludge drying machine and used for heating fresh air and supplying the heated fresh air to the sludge drying machine, and the first heat exchanger is connected with the fresh air heater and used for supplying heat required by the heated fresh air to the fresh air heater.

2. The sludge drying treatment equipment as claimed in claim 1, further comprising a second dust remover, wherein the second dust remover is a constant temperature dust remover, the air inlet end of the second dust remover is connected with the sludge dryer, and the air outlet end of the second dust remover is connected with the primary air pipe and/or the secondary air pipe.

3. The sludge drying treatment apparatus of claim 2, wherein the first heat exchanger is further connected to the second dust collector and is used for providing heat for the second dust collector.

4. The sludge drying treatment equipment as claimed in claim 2, further comprising a first condenser and a first demister, wherein the first condenser is arranged between the second dust remover and the primary air pipe or the secondary air pipe, and the first demister is arranged between the first condenser and the primary air pipe or the secondary air pipe.

5. The sludge drying treatment device as claimed in claim 4, further comprising a second condenser and a second demister, wherein the second condenser is disposed between the first demister and the primary air pipe or the secondary air pipe, and the second demister is disposed between the second condenser and the primary air pipe or the secondary air pipe.

6. The sludge drying treatment equipment as claimed in claim 5, further comprising a first cooling device and a second cooling device, wherein the first cooling device is connected with the first condenser and is used for providing condensed water required by the first condenser, and the second cooling device is connected with the second condenser and is used for providing chilled water required by the second condenser;

the first cooling device is a cooling tower, and the second cooling device is an air-cooled heat pump water chilling unit; the second cooling device is also connected with the fresh air heater and is used for recovering latent heat of condensed water and utilizing the latent heat to preheat fresh air.

7. The sludge drying treatment equipment as claimed in claim 5, further comprising an exhaust gas reheater, wherein the exhaust gas reheater is disposed between the second demister and the primary air pipe and/or the secondary air pipe;

the first heat exchanger is also connected with the waste gas reheater and is used for providing heat required by waste gas heating for the waste gas reheater.

8. The sludge drying treatment equipment as claimed in any one of claims 1 to 7, further comprising a sludge negative pressure bin, a screw conveying pump and a sludge former which are connected in sequence, wherein the sludge former is connected with the sludge dryer.

9. The sludge drying treatment apparatus as claimed in claim 8, further comprising a dry sludge bin, wherein the dry sludge bin is connected to the sludge dryer, and the dry sludge bin is further connected to the screw transfer pump.

10. The sludge drying treatment apparatus according to any one of claims 1 to 7, further comprising an incinerator connected to the sludge dryer for incinerating the dried sludge from the sludge dryer.

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