CN201206835Y - Sludge Treatment System Using Pulverized Coal Boiler in Power Station - Google Patents

Abstract

The utility model relates to a harmless and resourceful treatment system for solid waste, aiming to provide a sludge treatment system using a pulverized coal boiler of a power station. The system includes a sludge dryer, an incinerator, and a coal mill. The coal mill is respectively connected to the dryer and the incinerator through a conveyor belt; the sludge dryer is a screw rotary sludge drying molding machine, and the screw rotary The type sludge drying and forming machine includes a shell, and at least one hollow heat shaft connected to the transmission mechanism is installed inside. Several hollow paddles are arranged on the hollow heat shaft. The two ends of the hollow heat shaft are respectively connected to the heat carrier inlet. The middle part of the heat shaft passes through the shell to lead to the heat carrier outlet; the upper part of one end of the shell is provided with a wet material inlet, and the lower part of the other end is provided with a product outlet; the shell is provided with a jacket, and the jacket is provided with a steam inlet and a condensed water outlet . The sludge treatment system of the utility model can make full use of the calorific value of the sludge, and the volume of the sludge can be reduced by more than 90% after sludge treatment, and the effect is quick.

Description

Sludge Treatment System Using Pulverized Coal Boiler in Power Station

technical field

The utility model relates to a harmless and resourceful treatment system for solid waste, more specifically, the utility model relates to a sludge treatment system using a pulverized coal boiler of a power station.

Background technique

With the acceleration of my country's urbanization process and the strengthening of urban infrastructure construction, the urban sewage treatment rate has gradually increased, accompanied by a large amount of excess sludge. If these sludges cannot be treated in a timely, effective and stable manner, it will bring great hidden dangers to the safety of our regional environment and people's lives. Due to historical reasons, in the process of building sewage treatment plants in my country, there has always been the idea of "heavy water and light mud", and the treatment and disposal of sludge has not received due attention. In addition, industrial processes such as papermaking, chemical and pharmaceutical industries, and dredging of rivers and lakes also generate large amounts of sludge. The harmless treatment of sludge has become a major environmental protection problem that must be solved in the process of urban scientific development.

The main disposal methods of sludge are agricultural use, landfill and incineration. my country's sludge treatment technology is currently mainly agricultural and landfill. However, the most important thing about the use of sludge in agriculture is the use of safety issues. Since the sludge contains a large number of pathogenic bacteria, heavy metals are enriched, and chemical agents are added during the dehydration process, the efficacy and harmlessness of sludge fertilizers need further study. For landfill, because the sludge contains a large amount of harmful substances, it also has the disadvantages of high water content and easy blockage of landfill seepage pipes, so many landfills in many places have banned the acceptance of sewage sludge. Some disposal methods such as composting and brick making are used, but due to the difficulty in meeting some technical requirements in terms of environment and building quality, it is also impossible to implement environmentally controlled disposal on a large scale.

The treatment method with incineration as the core is currently the most thorough, fast and economical method for sludge disposal. It can carbonize all organic matter and minimize the volume of sludge (90% volume reduction). The energy is converted into electric energy or heat energy, turning waste into treasure, so that the sludge can be fully utilized.

Sludge incineration is divided into direct incineration and incineration after drying. The direct incineration of sludge is to incinerate high-humidity (moisture content above 80%) sludge directly in the incinerator under the condition of auxiliary fuel as the heat source. Due to the high water content and low calorific value of wet sludge, a large amount of auxiliary fuel is required, and the amount of flue gas after incineration is also relatively large. The subsequent tail gas treatment requires huge equipment, and the operation and control are difficult, especially in existing coal-fired boilers. Co-burning a large amount of wet sludge has a very adverse effect on the safe operation of the equipment and environmental protection. Therefore, from a comprehensive perspective, the pre-drying of sludge into fuel has obvious advantages. To use sludge as fuel, unique drying and combustion technologies must be developed to convert sludge with low calorific value into usable fuel with higher calorific value, and then cleanly burn the sludge fuel through an incinerator.

In the prior art, the drying and forming of wet sludge is generally step-by-step. For example, after drying in a drying rotary kiln, it is sent to a crushing equipment for crushing to obtain sludge particles. This process requires the establishment of a rotary kiln and crushing equipment. At the same time, the rotary kiln also needs to provide additional heating facilities, and the overall cost is relatively high.

Sludge incineration technology is currently widely used, mainly multi-chamber, rotary and fluidized bed. However, a new set of sludge drying and incineration equipment must include a complete set of sludge drying heat source, incinerator and exhaust gas purification system. The investment price is relatively expensive and the construction period is relatively long. Due to the shortage of land resources in some cities, It is very difficult to build a new dedicated disposal project.

However, thermal power plants are often built around cities, and the sludge is directly mixed into the pulverized coal furnace of the existing power plant for incineration. There is no need for additional incineration and tail gas treatment equipment, and there is no need for major transformation of the original combustion system, which greatly reduces The investment and operating costs of sludge treatment, so the sludge incineration treatment system using pulverized coal boilers in power plants is a promising sludge treatment system.

Utility model content

The purpose of the utility model is to provide a sludge treatment system using a pulverized coal boiler of a power station.

In order to solve the above technical problems, the utility model is achieved through the following technical solutions:

A sludge treatment system using pulverized coal boilers in power stations, including a sludge dryer, an incinerator, and a coal mill, which are respectively connected to the dryer and the incinerator through a conveyor belt; the sludge dryer is a spiral Rotary sludge drying and forming machine, the screw rotary sludge drying and forming machine includes a shell, inside which is installed at least one hollow thermal shaft connected to the transmission mechanism, a number of hollow paddles are arranged on the hollow thermal shaft, and the hollow thermal shaft The two ends of the two ends are respectively connected to the heat carrier inlet, and the middle part of the hollow heat shaft passes through the shell to lead to the heat carrier outlet; the upper part of one end of the shell is provided with a wet material inlet, and the lower part of the other end is provided with a product outlet; the shell is provided with a jacket , steam inlet and condensate outlet are set on the jacket.

As an improvement of the utility model, the spiral rotary sludge drying and molding machine has two hollow heat shafts.

As an improvement of the utility model, the blades of the spiral rotary sludge drying and forming machine are wedge-shaped, and are obliquely installed on the hollow heat shaft.

As an improvement of the utility model, the blades of the screw rotary sludge drying molding machine are propeller blades.

As an improvement of the utility model, an air inlet and an air outlet are also provided on the housing of the spiral rotary sludge drying and forming machine.

As an improvement of the utility model, the incinerator is a pulverized coal boiler of a power station; the sludge is dried by a sludge dryer and sent to a coal mill for grinding, and then the ground mixture is sent to a pulverized coal boiler of a power station incineration.

Compared with the prior art, the beneficial effects of the utility model are:

(1) The drying and molding machine completes the drying and molding of wet sludge at one time, and the space of the dryer becomes smaller and smaller as the sludge dries, saving equipment investment;

(2) Use the low-grade turbine steam that has done work in the power plant to dry the sludge to fully save energy;

(3) The sludge is made into granular shaped fuel, which is conducive to further grinding and incineration;

(4) The calorific value in the sludge can be fully utilized after the sludge particles are turned into fuel, and the volume of the sludge can be reduced by more than 90% after drying treatment, which has important application value for solving the urgent problem of urban sewage sludge treatment in our country.

(5) There is no need to add additional incineration and flue gas treatment equipment, and the existing power plant equipment can be used, which greatly saves investment and cost.

Description of drawings

Fig. 1 is the process flow diagram in the embodiment in the utility model.

Fig. 2 is a schematic structural view of the spiral rotary sludge drying molding machine in the present invention;

Fig. 3 is a schematic cross-sectional structure diagram of the spiral rotary sludge drying molding machine in the utility model;

Fig. 4 is a schematic diagram of the hollow heat shaft structure of the spiral rotary sludge drying molding machine in the utility model;

Fig. 5 is a schematic diagram of the wedge-shaped paddle structure of the spiral rotary sludge drying molding machine in the present invention;

Fig. 6 is a schematic diagram of the wedge-shaped paddle structure of the spiral rotary sludge drying molding machine in the present invention;

In the figure: 1—W-shaped tank; 2—hollow thermal shaft; 3—top cover; 4—bearing and stuffing box; 5—jacket; 6—wedge blade; 7—gear; Rotary joint; 10—sprocket wheel.

Detailed ways

Referring to the accompanying drawings, the utility model will be described in detail below in conjunction with the embodiments.

A sludge treatment system using pulverized coal boilers in power stations, including a sludge dryer, an incinerator, and a coal mill, which are respectively connected to the dryer and the incinerator through a conveyor belt; the sludge dryer is a spiral Rotary sludge drying and forming machine, the spiral rotary sludge drying and forming machine is equipped with two hollow thermal shafts 2 connected to the transmission mechanism, and a number of hollow wedge-shaped paddles 6 are arranged on the hollow thermal shafts 2, and the interiors are connected. The two ends of the hollow thermal shaft 2 are respectively connected to the heat carrier inlet, and the middle part of the hollow thermal shaft 2 passes through the shell to lead to the heat carrier outlet; the wedge-shaped paddle 6 is installed obliquely on the hollow thermal shaft 2, and the inclination direction allows the sludge material to flow The wedge-shaped paddle 6 pushes down and moves toward the discharge direction, and of course propeller blades or blades of other shapes can also be used. The upper part of the molding machine housing is a loam cake 3, one end of the loam cake 3 is provided with a wet material inlet, and the lower part of the other end of the housing is provided with a product outlet. The casing is also provided with an air inlet leading into dry air and an air exhaust outlet expelling wet gas. A jacket 5 is arranged on the shell, and a steam inlet and a condensed water outlet are arranged on the jacket 5 . The inner side of the jacket 5 forms a W-shaped groove body 1 adapted to the two hollow thermal shafts 2 . The transmission mechanism of the spiral rotary sludge drying molding machine includes a rotary joint 9, a sprocket 10, a speed reducing device 8, a gear 7, a bearing and a stuffing box 4, and the rotary joint 9 is connected to a power device such as a motor.

The incinerator is a pulverized coal boiler of a power station; the sludge is dried by a sludge dryer and sent to a coal mill for grinding, and then the ground mixture is sent to a pulverized coal boiler of a power station for incineration.

The operation mode of the sludge treatment system using the pulverized coal boiler of the power station is as follows:

(1) Making wet sludge into sludge particles with a moisture content of 20% to 40% and a particle size of 1 to 5 mm;

(2) The sludge particles obtained in the first step are sent into a coal mill together with the fuel coal for grinding;

(3) Send the ground mixture obtained in the second step into the pulverized coal boiler of the power station for incineration.

Specific embodiment 1:

Taking the sludge briquette fuel incineration project with a processing capacity of 300 tons/day as an example, the specific implementation of the utility model is described.

After transporting 300 tons/day of raw wet sludge (water content 85%) to the power plant, it is piled up in a closed raw sludge storage bin. It is transported to the sludge drying plant through sludge pumps and pipelines. The sludge is dried by 2 sets of spiral rotary sludge dryers, and the wet sludge treatment capacity of each dryer is 150 tons/day. The sludge is dried to become sludge particles with a water content of about 40% and a particle size of about 1mm, which are used as granular fuel. In the step of making the wet sludge into sludge granules, the wet sludge is heated by the low-grade steam after the work of the steam turbine. The dried sludge particles are sent to the dry sludge bin through belts or other conveying devices. The sludge particles in the dry sludge bin and the fuel coal in the dry coal shed are mixed and sent to the coal bunker in front of the furnace through the original coal conveyor belt. The mixed fuel in the coal bunker in front of the furnace is sent to the original coal mill of the power plant, and enters the pulverized coal boiler through the pulverized coal burner for incineration. The process flow is shown in Figure 1. Among them, the first link can be transported by belt or pump; the second link can also use conveying equipment such as twisted cages.

The operation mode of the spiral rotary sludge drying molding machine is as follows: the saturated steam after the work of the steam turbine is used as the heating heat source, the pressure is 0.4-0.8MPa, and the temperature is 175°C. Saturated steam from the boiler enters the jacket 5 of the shell from the steam inlet, and enters the hollow heat shaft 2 and the wedge-shaped paddle 6 from the heat carrier inlet, and heats the fuselage, the hollow heat shaft 2 and the wedge-shaped paddle 6 at the same time to conduct The way of heating is to heat and dry the sludge. The dried wet sludge is quantitatively and continuously fed into the dryer from the wet material inlet. After the sludge enters the machine body, the sludge is turned over and stirred by the rotation of the wedge-shaped paddle 6, and the heating interface is continuously updated to fully integrate with the heated material. The fuselage is in contact with the wedge-shaped paddle 6 and is fully heated to evaporate the surface moisture contained in the sludge. At the same time, the sludge is transported to the product outlet with the rotation of the blade shaft, and the stirring is continued during the transport, so that the water seeping out of the sludge continues to evaporate. Finally, the evenly dried sludge is discharged from the product outlet. During this process, a small amount of flue gas from the boiler tail is introduced into the drying molding machine to take away the water vapor continuously generated during the sludge drying process. The flue gas enters from the air inlet and is discharged from the air outlet. After the saturated steam is heat-exchanged and condensed, it is discharged through the condensed water outlet for reuse.

Specific embodiment 2:

In this embodiment, the moisture content of the wet sludge is 80%, the moisture content of the treated sludge pellets is 30%, and the particle size is 3 mm. The other implementation steps are the same as in Embodiment 1.

Specific embodiment 3:

In this embodiment, the moisture content of the wet sludge is 75%, the moisture content of the treated sludge pellets is 20%, and the particle size is 5 mm. The other implementation steps are the same as in Embodiment 1.

Finally, it should be noted that the above-mentioned examples are only specific implementation examples of the present invention. Apparently, the utility model is not limited to the above implementation examples, and many variations are possible. All deformations that a person skilled in the art can derive or associate directly from the content disclosed in the utility model shall be considered as the protection scope of the utility model.

Claims (6)

1. A sludge treatment system using a pulverized coal boiler in a power station, including a sludge dryer and an incinerator, characterized in that it also includes a coal mill, and the coal mill is connected to the dryer and the incinerator respectively through a conveyor belt; The sludge dryer is a spiral rotary sludge drying molding machine. The screw rotary sludge drying molding machine includes a shell, and at least one hollow thermal shaft connected to the transmission mechanism is installed inside it. Several hollow shafts are arranged on the hollow thermal shaft. The paddle, the two ends of the hollow thermal shaft are respectively connected to the heat carrier inlet, and the middle part of the hollow thermal shaft passes through the shell to lead to the heat carrier outlet; the upper part of one end of the shell is provided with a wet material inlet, and the lower part of the other end is provided with a product outlet; A jacket is arranged on the casing, and a steam inlet and a condensed water outlet are arranged on the jacket. 2. The sludge treatment system utilizing pulverized coal boilers in power stations according to claim 1, wherein the spiral rotary sludge drying molding machine has two hollow heat shafts. 3. The sludge treatment system using pulverized coal boilers in power plants according to claim 1, characterized in that the blades of the spiral rotary sludge drying and forming machine are wedge-shaped and installed obliquely on the hollow thermal shaft . 4. The sludge treatment system using pulverized coal boilers in power stations according to claim 1, wherein the blades of the screw rotary sludge drying and molding machine are propeller blades. 5. The sludge treatment system using pulverized coal boilers in power stations according to claim 1, characterized in that, the shell of the spiral rotary sludge drying and molding machine is also provided with an air inlet and an air outlet. 6. The sludge treatment system utilizing power station pulverized coal boiler according to claim 1, characterized in that, the incinerator is a power station pulverized coal boiler; the sludge is dried by a sludge dryer and sent to a coal mill for grinding system, and then the ground mixture is sent to the pulverized coal boiler of the power station for incineration.

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