CN113636736A

CN113636736A - Sludge treatment system and method

Info

Publication number: CN113636736A
Application number: CN202110740883.XA
Authority: CN
Inventors: 张华�; 曾晶; 张鲁峻; 康凌晨; 刘瑛; 叶兵; 周许林
Original assignee: Wuhan Iron and Steel Co Ltd
Current assignee: Wuhan Iron and Steel Co Ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2021-11-12

Abstract

The invention discloses a sludge treatment system and a method, wherein the system comprises: wet sludge bin, mixer, drum drier, electric dust remover, gas-solid separator, sieving device, crushing machine, dried sludge bin, dried sludge dust bin, coal mill and subsequent treatment subsystem. Wet sludge bin and blender entry intercommunication, blender export, electrostatic precipitator all communicate with rotary drum dryer entry, rotary drum dryer export and gas-solid separator entry intercommunication, the separator entry communicates with gas-solid separator export, the separator export communicates with crusher entry, mummification sludge bin and mummification sludge dust storehouse respectively, mummification sludge dust storehouse communicates with crusher export and blender entry respectively, mummification sludge bin and coal pulverizer intercommunication. The application utilizes the low-temperature exhaust smoke of the boiler to dry the rolling wet sludge, thereby uniformly and quickly drying the wet sludge under the condition of keeping the heat value of the sludge.

Description

Sludge treatment system and method

Technical Field

The invention relates to the technical field of waste treatment, in particular to a sludge treatment system and method.

Background

Iron and steel enterprises generate a large amount of sludge in the processes of iron and steel smelting and wastewater treatment, and the sludge mainly comes from a cyclone sedimentation tank, a horizontal sedimentation tank, a chemical oil remover, backwashing of a high-speed filter and the like. The sludge has complex components, relatively stable solid-liquid ratio, difficult sedimentation and great difficulty in sludge treatment under the condition of no external force intervention. The sludge contains various chemical substances, has high toxicity, emits foul smell, and causes great pollution to the natural environment and waste of a large amount of useful resources if directly discharged outside.

Therefore, an effective way for solving the sludge pollution of the iron and steel enterprises is urgently needed to be found, the comprehensive utilization rate of the sludge is improved, the waste is changed into the valuable, and the harm is turned into the benefit.

Disclosure of Invention

The embodiment of the application provides a sludge treatment system and method, which utilize low-temperature emission flue gas of a boiler to perform continuous rolling drying on wet sludge subjected to preliminary mixing of dry sludge and dust, so that the wet sludge is uniformly and quickly dried under the condition of keeping a sludge heat value, the dried sludge is sent to a coal mill to mix and burn coal, the comprehensive utilization rate of the sludge is improved, and the efficient operation of a sludge mixing and burning system is facilitated.

In a first aspect, the present invention provides the following technical solutions through an embodiment of the present invention:

a sludge treatment system comprising:

the method comprises the following steps: the system comprises a wet sludge bin, a mixer, a rotary drum dryer, an electric dust remover, a gas-solid separator, a screening device, a crushing machine, a dried sludge bin, a dried sludge dust bin, a coal mill and a subsequent treatment subsystem; the wet sludge bin is communicated with the mixer inlet, the mixer outlet and the electric dust remover are communicated with the drum dryer inlet, the drum dryer outlet is communicated with the gas-solid separator inlet, the screening device inlet is communicated with the gas-solid separator outlet, the screening device outlet is communicated with the crusher inlet, the dried sludge bin and the dried sludge dust bin respectively, the dried sludge dust bin is communicated with the crusher outlet and the mixer inlet respectively, and the dried sludge bin is communicated with the coal mill; the wet sludge bin is used for storing wet sludge, the mixer is used for mixing the wet sludge with dry sludge dust conveyed from the dry sludge dust bin, the drum dryer is used for performing rotary drying on the wet sludge under the action of boiler flue gas discharged from an outlet of the electric dust remover to obtain dry sludge, the electric dust remover is used for removing dust from the boiler flue gas, and the gas-solid separator is used for separating the dry sludge into gas and solid; the screening device is used for screening the separated dry sludge according to specification and size to obtain dry sludge dust, dry sludge particles and dry sludge blocks, conveying the dry sludge dust to the dried sludge dust bin, conveying the dry sludge blocks to the crushing machine, conveying the dry sludge particles to the dried sludge bin, crushing the dry sludge blocks into dust by the crushing machine, storing the dry sludge dust in the dried sludge dust bin, storing the dry sludge particles in the dried sludge bin, and mixing the dry sludge particles with fire coal by the coal mill; and the subsequent treatment subsystem is used for performing subsequent purification treatment on the separated gas.

Preferably, the moisture content of the wet sludge is 60% or more.

Preferably, the subsequent treatment subsystem comprises a cooler, an odor treatment device and a wastewater treatment device, wherein the inlet of the cooler is connected with the outlet of the gas-solid separator, and the outlet of the cooler is respectively connected with the odor treatment device and the wastewater treatment device; the cooler is used for cooling gas, produces foul smell and liquid, the foul smell processing apparatus is used for right the foul smell is handled, effluent treatment plant is used for right liquid is handled.

Preferably, the cooler is connected with an external coal-fired power generation unit turbine, and is used for returning condensed water heated by the gas in the cooler to the coal-fired power generation unit turbine to apply work to the turbine.

Preferably, the drum dryer performs rotary drying on the wet sludge for 25 minutes to 30 minutes.

Preferably, the boiler flue gas volume conveyed by the electric dust collector is 26-30 ten thousand cubic meters per hour, the speed matched with the boiler flue gas flow rate is 1-2 m/s, and the inlet temperature of the rotary drum dryer is 160-180 ℃.

Preferably, the particle size of the dry sludge dust is less than 0.5 mm, the particle size of the dry sludge particles is more than 0.5 mm and less than 10 mm, and the particle size of the dry sludge block is more than 10 mm.

Preferably, the system further comprises a screw delivery pump, the screw delivery pump is respectively connected with the wet sludge bin and the mixer, and the screw delivery pump is used for transporting wet sludge in the wet sludge bin to the mixer.

In a second aspect, the present invention provides the following technical solutions through an embodiment of the present invention:

a method of sludge treatment comprising:

controlling the wet sludge stored in a wet sludge bin to be transported into a mixer, and stopping the transportation when detecting that the weight of the wet sludge in the mixer reaches a first weight preset value;

controlling wet sludge in the mixer to be mixed with dry sludge dust conveyed from a dried sludge dust bin for preset time, and conveying the mixed wet sludge to a rotary drum dryer;

stopping transportation when the weight of the wet sludge in the rotary drum dryer reaches a second weight preset value is detected, and simultaneously starting the rotary drum dryer and the electric dust remover to ensure that the wet sludge conveyed into the rotary drum dryer is directly contacted with boiler flue gas from the outlet of the electric dust remover, and drying the wet sludge to obtain dry sludge;

after the drum dryer is controlled to work for a preset time, the dry sludge is sent to a gas-solid separator for gas-solid separation, the gas separated by the gas-solid separator is subjected to subsequent purification treatment, the dry sludge separated by the gas-solid separator enters a screening device, dry sludge dust, dry sludge particles and dry sludge blocks are obtained by screening, the dry sludge dust is sent to a dried sludge dust bin, the dry sludge blocks are sent to a crushing machine, and the dry sludge particles are sent to a dried sludge bin;

and controlling the crusher to crush the dry sludge blocks to obtain dry sludge dust, conveying the dry sludge dust to the dried sludge dust bin, and controlling the dried sludge particles in the dried sludge bin to be conveyed to a coal mill to be mixed with coal.

Preferably, the subsequent purification treatment comprises: cooling the gas by a cooler to generate odor and liquid; and purifying the odor by adopting an odor treatment device, and purifying the liquid by adopting a wastewater treatment device.

One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

the system comprises a wet sludge bin, a mixer, a rotary drum dryer, an electric dust remover, a gas-solid separator, a screening device, a crushing machine, a dried sludge bin, a dried sludge dust bin, a coal mill and a subsequent treatment subsystem. The moisture content of wet sludge is preliminarily reduced by fully mixing the wet sludge with dry sludge dust conveyed from a dry sludge dust bin. And conveying the mixed wet sludge into a rotary drum dryer, inputting boiler low-temperature exhaust smoke into the rotary drum dryer, and rotationally drying the wet sludge in the rotary drum dryer to obtain dry sludge. Because low-temperature drying is adopted, the heat value of the sludge is not damaged. Further, the dry sludge is separated into solid and gas, and the separated solid is divided into a plurality of sludge according to specification and size, namely dry sludge blocks, dry sludge particles and dry sludge dust, wherein the dry sludge particles are qualified sludge and are used for being conveyed to a coal mill to be mixed with fire coal; the dry sludge block and the dry sludge dust are unqualified sludge, and the dry sludge block is required to be conveyed to a crusher to be crushed into the dry sludge dust which is stored in a dry sludge dust bin to convey the dry sludge dust to a mixer, so that the purpose of classification is achieved, and the treatment precision and the treatment efficiency are improved. This application utilizes the boiler low temperature to discharge the flue gas, to the wet sludge after doing the preliminary mixing of mud dust, lasts the roll mummification to under the condition that remains the mud calorific value, carry out even fast mummification to wet sludge, send the mud of mummification to the coal pulverizer and mix the burning coal, improved the comprehensive utilization rate of mud, be favorable to the high-efficient operation of mud mixing the burning system.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a sludge treatment system according to an embodiment of the present invention;

FIG. 2 is a flow chart of a sludge treatment method according to an embodiment of the present invention.

Detailed Description

The sludge treatment of iron and steel enterprises aims at reducing, harmlessly treating and protecting the sludge, and the current sludge treatment mode comprises the following steps: sanitary landfill, drying and cooperative treatment, drying and incineration and the like. The sanitary landfill is characterized in that chemical substances of sludge are removed in a mechanical mode, dehydration and sterilization treatment are carried out, and then land landfill is carried out, so that the mode is large in occupied area and easy to cause secondary pollution; the drying and cooperative treatment means that sludge is dewatered to a certain solid content by a mechanical or thermal drying mode and then is cooperatively treated by utilizing existing facilities such as a coal-fired power plant, a garbage incineration plant, a cement plant and the like; the drying incineration means that combustible components in the sludge are fully combusted at high temperature, only a small amount of ash residues are left, and heat in high-temperature flue gas is recovered for sludge drying.

Sludge incineration in drying incineration can be divided into two main categories: firstly, the dewatered sludge is directly sent to an incinerator for incineration, and secondly, the sludge is dried and then incinerated. The water content of the sludge in the sewage treatment plant is high (the water content is more than 60 percent), so that a large amount of auxiliary fuel is required to be added for direct incineration, and the energy utilization rate is low. The sludge is dried and then incinerated, the energy utilization rate is high, even self-service combustion without adding auxiliary fuel can be realized, the process becomes a preferred process for sludge incineration treatment, particularly, the sludge drying can also enable the volume of the sludge to be obviously reduced, and the volume can be reduced by 4-5 times. The residual substances after drying are relatively stable, the foul smell and the pathogenic microorganisms are greatly removed, and the heat value and the nutrient content of the residual substances are kept.

Wherein, the sludge heat drying can be divided into three types, namely direct heating type, indirect heating type and direct-indirect combined drying type. The direct thermal drying has the advantages of high heat energy utilization rate, and capability of increasing the solid content of the sludge from 25 percent to 85 to 95 percent, and has the defects that combustible substances such as organic matters in the sludge are more likely to be taken away in the drying process, so that the heat value of the dry sludge is reduced, and the subsequent sludge coupling co-combustion is not facilitated. The indirect heating has the advantages that a heat source is not in direct contact with the sludge, so that the separation process of a heat medium and dry sludge is omitted, the heat transfer efficiency and the evaporation rate are poor, and organic matters in the sludge are not easy to decompose.

According to research, almost no organic matter is decomposed when the drying temperature is lower than 155 ℃, about 5 percent of organic matter is decomposed when the drying temperature is 200 ℃, and the calorific value of the residual dry sludge is only half of 100 ℃ when the drying temperature reaches 300 ℃. Wherein, the higher the sludge drying temperature is, the higher the pollutant emission concentration in the drying process is. The organic matters in the condensate liquid at 180 ℃ and 220 ℃ are mainly alcohol substances, the main organic matters are aldehydes at 260 ℃, the temperature has a promoting effect on sludge drying, the drying rate at a constant speed stage is increased along with the increase of the temperature, and the removal of water is reduced. Therefore, from the viewpoints of energy consumption, residual sludge combustion heat value and condensate treatment difficulty, the optimal sludge drying stage is preferably carried out at a constant speed of 145-185 ℃.

In view of the above, embodiments of the present application provide a sludge treatment system and method, which utilize low-temperature exhaust flue gas of a boiler to perform continuous rolling drying on wet sludge after primary mixing of dry sludge and dust, so as to perform uniform and rapid drying on the wet sludge while retaining the heat value of the sludge.

In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and specific embodiments. The wet sludge water content of the present application is 60% or more. For example, the moisture content of the wet sludge is 60%, 65%, or 70%.

In a first aspect, an embodiment of the present invention provides a sludge treatment system, specifically, as shown in fig. 1, the system includes: the system comprises a wet sludge bin 1, a mixer 2, a rotary drum dryer 3, an electric dust remover 4, a gas-solid separator 5, a screening device 6, a crushing machine 7, a dried sludge dust bin 8, a dried sludge bin 9, a coal mill 10 and a subsequent treatment subsystem 11.

Wherein,

wet sludge bin

1 and 2 entry intercommunications of blender, 2 exports of blender, electrostatic precipitator 4 all communicates with 3 entries of rotary drum dryer, 3 exports of rotary drum dryer and 5 entries of gas-solid separator intercommunication, 6 entrances of sieve separator and 5 exports of gas-solid separator intercommunication, 6 exports of sieve separator respectively with 7 entries of crusher, mummification sludge dust bin 8 and mummification sludge bin 9 intercommunication, mummification sludge dust bin 8 exports and 2 entry intercommunications of blender with 7 of crusher respectively, mummification sludge bin 9 and coal pulverizer 10 intercommunication.

In specific implementation, wet sludge of steel enterprises is conveyed to the wet sludge bin 1 for storage and weighing, and then conveyed to the mixer 2 through the spiral conveying pump. The mixer 2 fully mixes the wet sludge and the dry sludge dust conveyed from the dry sludge dust bin 9 to reduce the moisture content of the wet sludge, avoid the wet sludge from bonding in the conveying process and effectively improve the production efficiency of the system. And (3) delivering the mixed wet sludge to a rotary drum dryer (3), and uniformly overturning the wet sludge by the rotary drum dryer (3). Meanwhile, the low-temperature flue gas of the coal-fired boiler in a certain temperature range is conveyed into the rotary drum dryer 3 after being dedusted by the electric precipitator 4. The boiler flue gas is directly contacted with wet sludge, and the wet sludge is dried in a rotating mode, so that the wet sludge is dried uniformly and quickly through low-temperature drying treatment under the condition that the heat value of the sludge is kept, and the dry sludge is obtained.

In order to improve the efficiency of obtaining dry sludge, the time of the drum dryer 3 acting on wet sludge may be set according to specific conditions, for example: the drum dryer performs rotary drying on the wet sludge for 25 minutes to 30 minutes.

In the specific implementation, in order to achieve a good drying effect, the amount of boiler flue gas conveyed by the electric dust collector is 26-30 ten thousand cubic meters per hour, the speed of the boiler flue gas flow rate is 1-2 m/s, and the inlet temperature of the rotary drum dryer is 160-180 ℃.

Preferably, the boiler flue gas volume conveyed to the drum dryer can be 26 ten thousand cubic meters per hour, the speed of matching the flow rate of the boiler flue gas is 1-2 m/s, the inlet temperature of the drum dryer is 170 ℃, and the outlet temperature of the drum dryer is 107 ℃. Through the operation process, the water content of the dry sludge is reduced to 30%, the output dry sludge amount is 6 tons/hour, the heat energy efficiency of the discharged flue gas is improved by 4%, the smoke exhaust temperature of the boiler is reduced by more than 60 ℃, and the efficient operation of the sludge co-combustion system is realized.

Therefore, the method has the advantages that low-temperature flue gas discharged by the boiler is blown into the rotary drum dryer, wet sludge of a steel enterprise with a large water content is directly dried, the requirements of the process on high proportion and high heat value of mixed sludge combustion can be met, the sludge drying time is short, the occupied area of the device is small, and the waste heat of the discharged flue gas is efficiently utilized. Meanwhile, the low-temperature flue gas drying is adopted, so that bacteria and viruses carried in the sludge can be better eliminated, the volatilization of a large amount of organic matters can be effectively avoided, the release of malodorous gases (such as H2S and NH3) is reduced, and the heat value of the sludge is preserved.

The dried dry sludge is conveyed to the gas-solid separator 5 to be separated into gas and solid, the gas is conveyed to the subsequent treatment subsystem 11, and the subsequent treatment subsystem 11 carries out subsequent purification treatment on the separated gas. The separated solid is conveyed to a screening device 6, the screening device 6 screens the collected dry sludge according to the specification and size, and dry sludge dust, dry sludge granules and dry sludge blocks are obtained. The dry sludge dust is conveyed to a dry sludge dust bin 8, the dry sludge cake is conveyed to a crusher 7, and the dry sludge particles are conveyed to a dry sludge bin 9. The crusher 7 can crush the dry sludge blocks into dust and then convey the dust to the dry sludge dust bin 8. The dried sludge dust bin 8 is used for storing the dry sludge dust, and the dry sludge dust is returned to the mixer 2 through the conveyer belt. The dried sludge bin 9 is used for storing dried sludge particles, and conveying the dried sludge particles to the coal mill 10 through a conveying belt to mix and burn coal.

Preferably, the dry sludge is screened according to specification and size to obtain dry sludge dust, dry sludge particles and dry sludge blocks, wherein the particle size of the dry sludge dust is less than 0.5 mm, the particle size of the dry sludge particles is more than 0.5 mm and less than 10 mm, and the particle size of the dry sludge blocks is more than 10 mm. Therefore, qualified sludge (namely dry sludge granules) and unqualified sludge (namely dry sludge blocks and dry sludge dust) are obtained, and the obtained qualified sludge is conveyed to a coal mill to be mixed with fire coal, so that the comprehensive utilization rate of the sludge is improved, and the efficient operation of a sludge co-combustion system is facilitated.

Further, the post-processing subsystem 11 may include: the cooler 110 and the odor treatment device 111 are connected to a wastewater treatment device (not shown), the inlet of the cooler 110 is connected to the outlet of the gas-solid separator 5, and the outlet of the cooler 110 is connected to the odor treatment device 111 and the wastewater treatment device, respectively. The cooler 110 is used to cool the gas to generate odor and liquid, the odor treatment device 111 is used to treat the emitted odor, and the wastewater treatment device is used to treat the liquid.

Further, in order to reduce the steam consumption of a steam turbine in a coal-fired power generating unit, the energy is effectively utilized. The cooler 110 may be coupled to an external coal-fired power unit turbine 112 for returning condensed water heated by the gas in the cooler to the coal-fired power unit turbine to apply work to the turbine.

Specifically, a cooler is additionally arranged on a main pipe of gas flowing out of a gas-solid separator to separate gas from liquid, and the flowing gas has a certain temperature, so that the temperature of the gas is transmitted to a condensation pipe of the cooler based on the heat exchange principle of the cooler, and condensed water in the condensation pipe is heated, and part of the condensed water is formed into steam. The steam flows into a steam turbine of the coal-fired power generating set through the condensed water inlet pipe, the steam turbine is acted, and the heat energy of the gas is recycled through the way. The condensed water after acting flows into the condensing pipe through the condensed water outlet pipe, so that the cyclic utilization is realized.

It should be noted that when the maximum discharge amount of the odor is 25 million cubic meters per hour and the maximum discharge amount of the liquid is 4.4 tons per hour, the maximum amount of the steam used in the steam turbine can be reduced by 1.2 tons per hour by this function.

As an alternative example, the sludge treatment system provided by the present application may include a control flow that:

and controlling the wet sludge stored in the wet sludge bin to be transported into the mixer, and stopping the transportation when detecting that the weight of the wet sludge in the mixer reaches a first weight preset value. Wherein the first weight preset value may be a fixed value designed based on the capacity of the mixer. And controlling wet sludge to be mixed with dry sludge dust conveyed from the dry sludge dust bin in the mixer for a preset time, and then conveying the mixed wet sludge to the rotary drum dryer. In order to achieve sufficient mixing of the dry sludge dust and the wet sludge, the preset mixing time can be set according to actual conditions, for example, the preset mixing time is 5-10 minutes.

And stopping transportation when the weight of the wet sludge in the rotary drum dryer is detected to reach a second weight preset value, and simultaneously starting the rotary drum dryer and the electric dust remover, so that the wet sludge conveyed into the rotary drum dryer is directly contacted with the boiler flue gas from the outlet of the electric dust remover, and the wet sludge is dried to obtain dry sludge. The second weight preset value here may be a fixed value designed based on the capacity and power of the drum dryer.

Controlling the drum dryer to work for a preset time, then sending the dry sludge to a gas-solid separator for gas-solid separation, carrying out subsequent purification treatment on the gas separated by the gas-solid separator, feeding the dry sludge separated by the gas-solid separator into a screening device, screening to obtain dry sludge dust, dry sludge particles and dry sludge blocks, conveying the dry sludge dust to a dried sludge dust bin, conveying the dry sludge blocks to a crushing machine, and conveying the dry sludge particles to the dried sludge bin. Wherein, the preset time for the drum dryer to work can be 25-30 minutes.

And controlling a crusher to crush the dry sludge blocks to obtain dry sludge dust, conveying the dry sludge dust to a dried sludge dust bin, and meanwhile, controlling dry sludge particles in the dried sludge bin to be conveyed to a coal mill to be mixed with coal.

As an alternative embodiment, when it is detected that the dry sludge cake inside the crusher satisfies a preset crushing condition, the crusher is controlled to crush the dry sludge cake; and when detecting that the dry sludge particles in the dried sludge bin meet the preset mixing condition, controlling the dry sludge particles to be conveyed to a coal mill to be mixed with the coal.

For example, the crushing condition may be that when the dry sludge cake accumulated reaches one third of the capacity of the crusher, the crusher is controlled to crush the dry sludge cake; the mixing condition can be that when the accumulated dry sludge particles reach one third of the capacity of the dried sludge bin, the dry sludge particles are controlled to be conveyed to a coal mill to be mixed with the coal.

The above technical solution will be exemplified below with reference to the actual situation of the sludge treatment system.

Example one

The method is characterized in that low-temperature discharged flue gas conveyed by a boiler electric dust remover is directly used for drying wet sludge in a rotary drum dryer, and the moisture content of the wet sludge is reduced to 40 percent from 60 percent, and the method comprises the following steps:

and (3) mixing 10 tons/hour of wet sludge with the dried sludge dust in the mixer through a screw conveying pump, then conveying the mixture to a drum dryer, drying for 25 minutes, and then conveying the mixture to a gas-solid separator, a sieving device, a crushing machine, a dried sludge dust bin and a dried sludge bin, wherein the moisture content of the wet sludge is reduced to 40%.

And then the dry sludge dust is conveyed to the mixer by a conveying belt at 0.5 ton/hour to be mixed with wet sludge, and the viscosity of the wet sludge is improved so as to be beneficial to conveying the sludge.

The dry sludge particles with qualified particle size are sent to a coal mill by a conveyer belt at the rate of 6.2 tons/hour to mix and burn the fire coal. The inlet temperature of the low-temperature discharged flue gas conveyed by the electric dust collector in the rotary drum dryer is 170 ℃, the outlet flue gas temperature is 114 ℃, and the use amount of the flue gas is 23 ten thousand m 3/h. The emission amount of the odor from the cooler is 23.2 ten thousand cubic meters per hour, and the odor is sent to an odor treatment device for treatment.

The amount of condensed waste water from the cooler was 3.3 tons/hr and was sent to a waste water treatment apparatus. Wherein the temperature of low-temperature exhaust flue gas is reduced by 56 ℃, the waste heat of the boiler is recovered by 2 percent, and the steam consumption of the steam turbine is reduced by 0.8 ton/hour by absorbing the waste heat of gas by condensed water.

Example two

The method is characterized in that low-temperature discharged flue gas conveyed by a boiler electric dust remover is directly used for drying wet sludge in a rotary drum dryer, and the moisture content of the wet sludge is reduced to 30 percent by 60 percent, and the method comprises the following steps:

mixing the wet sludge with the dried sludge dust in a mixer at a rate of 10 tons/hour by a screw conveying pump, then conveying the mixture to a drum dryer, drying the mixture for 27 minutes, and then conveying the dried sludge dust to a gas-solid separator, a sieving device, a crushing machine, a dried sludge dust bin and a dried sludge bin, wherein the moisture content of the wet sludge is reduced to 30 percent.

The dry sludge powder layer is conveyed to a mixer by a conveyer belt at a rate of 0.7 ton/hour and is mixed with wet sludge, so that the viscosity of the wet sludge is improved to be beneficial to conveying the sludge; and 5.1 tons of dry sludge with qualified particle size is conveyed to a coal mill through a conveyer belt and is mixed with burning coal.

The inlet temperature of the low-temperature discharged flue gas conveyed by the electric dust collector in the rotary drum dryer is 170 ℃, the outlet flue gas temperature is 110 ℃, and the use amount of the flue gas is 24 ten-thousand m 3/h.

The discharge amount of the odor discharged from the cooler is 24.3 ten thousand cubic meters per hour, and the odor is sent to an odor treatment device for treatment; the amount of condensed waste water from the cooler was 4.2 tons/hr and sent to a waste water treatment apparatus.

Wherein the low-temperature exhaust gas temperature is reduced by 60 ℃, the boiler waste heat is recovered by 2.4 percent, and the steam consumption of the steam turbine is reduced by 1 ton/hour by absorbing the waste heat of the gas by the condensed water.

EXAMPLE III

The method is characterized in that low-temperature discharged flue gas conveyed by a boiler electric dust remover is directly used for drying wet sludge in a rotary drum dryer, and the moisture content of the wet sludge is reduced to 20 percent from 60 percent, and the method comprises the following steps:

mixing the wet sludge with the dried sludge dust in a mixer at a rate of 10 tons/hour by a screw conveying pump, then conveying the mixture to a drum dryer, drying the mixture for 30 minutes, and then conveying the dried sludge dust to a gas-solid separator, a sieving device, a crushing machine, a dried sludge dust bin and a dried sludge bin, wherein the moisture content of the wet sludge is reduced to 20%.

The dry sludge powder layer is conveyed to a mixer through a conveyer belt at a rate of 1.1 ton/hour and is mixed with wet sludge, so that the viscosity of the wet sludge is improved to be beneficial to conveying the sludge; the dry sludge with qualified grain size is delivered to a coal mill for mixing and burning coal by a conveyer belt at a rate of 4.6 tons/hour.

The inlet temperature of the low-temperature discharged flue gas conveyed by the electric dust collector in the rotary drum dryer is 170 ℃, the outlet flue gas temperature is 107 ℃, and the use amount of the flue gas is 26 ten thousand m 3/h.

The discharge amount of the odor discharged from the cooler is 25.1 ten thousand cubic meters per hour, and the odor is sent to an odor treatment device for treatment; the amount of condensed waste water from the cooler was 4.4 t/hr and was sent to a waste water treatment apparatus.

Wherein the low-temperature exhaust gas temperature is reduced by 63 ℃, the boiler waste heat is recovered by 2.6 percent, and the steam consumption of the steam turbine is reduced by 1.2 tons/hour by absorbing the waste heat of the gas by the condensed water.

Finally, the water content of the dried sludge is distributed between 40% and 20% by analyzing the heat value of the dried sludge, and the heat value of the sludge can meet the production requirements.

The inventor discovers that the increase rate of the flue gas consumption is lower than that of other examples, the cost is too high when the moisture content of the sludge is reduced to 20%, the amount of dust generated by the dried sludge is greatly increased, and the requirement on transportation and protection measures in the process of the dried sludge is too high through comparative analysis of the above examples, so that the sludge is recommended to be dried to the moisture content of 30%.

To sum up, the sludge treatment system that this application provided sends wet mud of iron and steel enterprise to the rotary drum dryer, adjusts the low temperature discharge flue gas volume that comes from the export of boiler electrostatic precipitator and dries it for moisture that wet mud contains can be got rid of in the drying process. Meanwhile, the gas discharged from the outlet of the gas-solid separator can heat the condensed water in the cooler, so that the condensed water is formed into steam and is conveyed to the steam turbine, and the steam consumption of the steam turbine is reduced. By utilizing the heat value of low-temperature flue gas discharged by the boiler, the sludge combustion performance of iron and steel enterprises can be obviously improved, and the waste heat recycling efficiency of the boiler is improved.

The method solves the problems of economic operation, safety and environmental protection of the sludge of the coal-fired unit in the high-proportion mixed-burning iron and steel enterprises, the adopted equipment does not need high cost, and the realized process is simple, so the method has the advantages of small reconstruction investment, short construction period and the like, has good technical economy and social benefits, and can be popularized and applied to the treatment of municipal sludge.

In a second aspect, based on the same inventive concept, the present embodiment provides a sludge treatment method, which is applied to the system of the first aspect, as shown in fig. 2, and comprises the following steps S101 to S105.

S101, controlling wet sludge stored in a wet sludge bin to be transported to a mixer, and stopping transporting when the weight of the wet sludge in the mixer is detected to reach a first preset weight value;

step S102, controlling wet sludge to be mixed with dry sludge dust conveyed from a dry sludge dust bin in a mixer for a preset time, and then conveying the mixed wet sludge to a rotary drum dryer;

step S103, stopping transportation when the weight of the wet sludge in the rotary drum dryer reaches a second weight preset value is detected, and simultaneously starting the rotary drum dryer and the electric dust remover to enable the wet sludge conveyed into the rotary drum dryer to be directly contacted with boiler flue gas from the outlet of the electric dust remover, so that the wet sludge is dried to obtain dry sludge;

step S104, after the drum dryer is controlled to work for a preset time, the dry sludge is sent to a gas-solid separator for gas-solid separation, the gas separated by the gas-solid separator is subjected to subsequent purification treatment, the dry sludge separated by the gas-solid separator enters a screening device, dry sludge dust, dry sludge particles and dry sludge blocks are obtained by screening, the dry sludge dust is conveyed to a dried sludge dust bin, the dry sludge blocks are conveyed to a crushing machine, and the dry sludge particles are conveyed to a dried sludge bin;

and S105, controlling a crusher to crush the dry sludge blocks to obtain dry sludge dust, conveying the dry sludge dust to a dry sludge dust bin, and controlling dry sludge particles in the dry sludge bin to be conveyed to a coal mill to be mixed with fire coal.

As an alternative embodiment, the subsequent purification treatment comprises: cooling the gas by a cooler to generate odor and liquid; and adopting an odor treatment device to purify the odor, and adopting a wastewater treatment device to purify the liquid.

It should be noted that, the implementation principle and the generated technical effect of the sludge treatment method provided by the embodiment of the present invention are the same as those of the foregoing system embodiment, and for the sake of brief description, reference may be made to the corresponding contents in the foregoing system embodiment for the part of the embodiment of the apparatus that is not mentioned. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A sludge treatment system, comprising: the system comprises a wet sludge bin, a mixer, a rotary drum dryer, an electric dust remover, a gas-solid separator, a screening device, a crushing machine, a dried sludge bin, a dried sludge dust bin, a coal mill and a subsequent treatment subsystem;

the wet sludge bin is communicated with the mixer inlet, the mixer outlet and the electric dust remover are communicated with the drum dryer inlet, the drum dryer outlet is communicated with the gas-solid separator inlet, the screening device inlet is communicated with the gas-solid separator outlet, the screening device outlet is communicated with the crusher inlet, the dried sludge bin and the dried sludge dust bin respectively, the dried sludge dust bin is communicated with the crusher outlet and the mixer inlet respectively, and the dried sludge bin is communicated with the coal mill;

the wet sludge bin is used for storing wet sludge, the mixer is used for mixing the wet sludge with dry sludge dust conveyed from the dry sludge dust bin, the drum dryer is used for performing rotary drying on the wet sludge under the action of boiler flue gas discharged from the outlet of the electric dust remover to obtain dry sludge, the electric dust remover is used for removing dust from the boiler flue gas, and the gas-solid separator is used for separating the dry sludge into gas and solid;

the screening device is used for screening the separated dry sludge according to specification and size to obtain dry sludge dust, dry sludge particles and dry sludge blocks, conveying the dry sludge dust to the dried sludge dust bin, conveying the dry sludge blocks to the crushing machine, conveying the dry sludge particles to the dried sludge bin, crushing the dry sludge blocks into dust by the crushing machine, storing the dry sludge dust in the dried sludge dust bin, storing the dry sludge particles in the dried sludge bin, and mixing the dry sludge particles with fire coal by the coal mill; and the subsequent treatment subsystem is used for performing subsequent purification treatment on the separated gas.

2. The system of claim 1, wherein the wet sludge has a water content of 60% or more.

3. The system of claim 1, wherein the post-treatment subsystem comprises a cooler, an odor treatment device, and a wastewater treatment device, the cooler inlet being connected to the gas-solid separator outlet, the cooler outlet being connected to the odor treatment device and the wastewater treatment device, respectively;

the cooling device is used for cooling gas to generate odor and liquid, the odor treatment device is used for treating the odor treatment device, and the wastewater treatment device is used for treating the liquid.

4. The system of claim 3, wherein the cooler is coupled to an external coal-fired power unit turbine for returning condensate heated by the gas in the cooler to the coal-fired power unit turbine to apply work to the turbine.

5. The system of claim 1, wherein the drum dryer spin-dries the wet sludge for a time period of 25 minutes to 30 minutes.

6. The system of claim 1, wherein the boiler flue gas volume conveyed by the electric dust collector is 26-30 ten thousand cubic meters per hour, the speed of boiler flue gas flow rate matching is 1-2 m/s, and the inlet temperature of the rotary drum dryer is 160-180 ℃.

7. The system of claim 1, wherein the dry sludge dust has a particle size of less than 0.5 mm, the dry sludge particles have a particle size of greater than 0.5 mm and less than 10 mm, and the dry sludge cake has a particle size of greater than 10 mm.

8. The system of claim 1, further comprising a screw pump connected to the wet sludge bin and the mixer, respectively, for transporting wet sludge from the wet sludge bin to the mixer.

9. A method of sludge treatment, for use in the system of claims 1-8, the method comprising:

controlling the wet sludge in the mixer and the dry sludge dust conveyed from the dried sludge dust bin to be mixed for a preset time, and conveying the mixed wet sludge to a rotary drum dryer;

stopping transportation when the weight of wet sludge in the rotary drum dryer reaches a second weight preset value is detected, and simultaneously starting the rotary drum dryer and the electric dust remover to ensure that the wet sludge conveyed into the rotary drum dryer is directly contacted with boiler flue gas from the outlet of the electric dust remover to dry the wet sludge to obtain dry sludge;

10. The method of claim 9, wherein the subsequent purge process comprises:

cooling the separated gas by a cooler to produce an odor and a liquid;

and purifying the odor by adopting an odor treatment device, and purifying the liquid by adopting a wastewater treatment device.