Kiln tail waste gas collection, treatment and utilization system for rotary kiln pulverized coal preparation workshop

Abstract

The utility model discloses a system for collecting, treating and utilizing kiln tail waste gas of a rotary kiln pulverized coal preparation workshop, which is characterized in that an outlet of a waste gas pipeline is communicated with a kiln tail preheater, then connected with a cyclone dust collector and then connected with an induced draft fan I, and an outlet of the induced draft fan is connected with a cloth bag dust collection mechanism and an underground dust collection mechanism in parallel; the cloth bag dust removal mechanism is composed of a large cloth bag dust collector, an induced draft fan II, a desulfurization tower and a waste gas emission chimney which are connected in sequence; the underground dust collection mechanism is composed of a first dust collector, a motor, an air heater, a ball mill, a powder concentrator and a second dust collector which are sequentially connected. After impurities and particulate matters in waste gas are efficiently treated by the system, the waste gas with residual heat is used as kiln tail hot air of a pulverized coal system for drying, so that the moisture of pulverized coal is reduced, the calorific value of the pulverized coal is increased, and meanwhile, the problem of ring formation of the pulverized coal preparation system is reduced; compared with the prior art that the waste gas directly enters a cloth bag dust removal tank through an induced draft fan, the device has the characteristics of good kiln tail heat utilization and good waste gas recycling effect.

Description

Technical Field

[0001] The utility model belongs to the technical field of rotary kiln design, relates to rotary kiln waste heat utilization and dust control technology, and specifically relates to a rotary kiln coal powder preparation workshop kiln tail waste gas collection, treatment and utilization system. Background Art

[0002] At present, rotary kiln equipment consists of the main parts such as the cylinder, kiln head and kiln tail. The mechanical, physical or chemical treatment of solid materials has been widely used in many production industries such as building materials, metallurgy, and chemical industry. The current rotary kiln process has the advantages of low raw burning, high lime quality, flexible adjustment, low operating cost, and ultra-low emissions. The process is relatively stable and mature, but it still has the disadvantages of high energy consumption and low thermal energy utilization.

[0003] The pulverized coal preparation process is a set of process flows that provide heat and energy for the rotary kiln. It usually uses high-quality coal with low ash and sulfur content, and crushes and screens the coal to obtain pulverized coal. Its shortcomings are: 1. The moisture content of the raw coal is relatively high, and directly entering the pulverized coal preparation process does not optimize the production process of pulverized coal, reduces coal milling efficiency and safety performance, and increases energy consumption and pollution emissions. 2. The rotary kiln tail fails to recover the exhaust heat in time for utilization, resulting in serious waste of flue gas waste heat, which does not meet the ultimate requirements of sustainable development of the enterprise.

[0004] At present, the waste gas treatment of high-temperature rotary kiln includes two links: cooling and purification. The tail gas of the kiln directly passes through the cyclone dust removal tank and then enters the large bag dust collector for dust removal, and then enters the desulfurization tower through the induced draft fan for desulfurization and denitrification. This process method wastes the thermal energy of the tail gas of the kiln and fails to realize the recovery and utilization of waste heat. Summary of the invention

[0005] The utility model discloses a waste gas collection, treatment and utilization system at the kiln tail of a rotary kiln coal powder preparation workshop. The utility model aims to provide a waste gas and dust collection and utilization system applied to a high-temperature rotary kiln.

[0006] The utility model is realized by the following technical solutions:

[0007] The exhaust gas collection, treatment and utilization system at the tail of a rotary kiln, wherein the exhaust gas pipeline outlet at the tail of a rotary kiln is connected to the tail preheater of the kiln; the outlet of the tail preheater of the kiln is connected to the cyclone dust collector, the outlet of the cyclone dust collector is connected to the induced draft fan 1, and the outlet of the induced draft fan is connected in parallel to the bag dust removal mechanism and the underground dust collection mechanism;

[0008] The bag dust removal mechanism is composed of a large bag dust collector, a second induced draft fan, a desulfurization tower and an exhaust gas emission chimney connected in sequence;

[0009] The underground dust collecting mechanism is composed of a dust collector 1, a motor, a hot air blower, a ball mill, a powder classifier and a dust collector 2 which are connected in sequence.

[0010] The bag dust removal mechanism and the underground dust collection mechanism inlet connected in parallel to the induced draft fan outlet are respectively provided with an openable and closable inlet gate.

[0011] In the process of producing active lime in the rotary kiln, due to the rotation of the rotary kiln and the negative pressure suction force generated by the smoke exhaust fan, the flue gas containing powder must be discharged through the outlet flue of the kiln tail preheater. The outlet flue is connected to the cyclone dust collector. The cyclone dust collector uses the inertial force generated by the deflection caused by the swirling motion of the airflow to separate and settle the dust in the tail gas for the first time. The air outlet of the cyclone dust collector is connected to the hood pipeline through the 1# induced draft fan and a main pipeline, and is respectively connected to the bag dust ash tank and the underground dust collector. The underground dust collector is connected to the underground pipeline to the pulverized coal system, which can be used as hot air at the kiln tail of the pulverized coal preparation workshop and circulated in the pulverized coal preparation system.

[0012] After the system of the utility model processes the impurities and particulates in the exhaust gas efficiently, it utilizes the waste heat of the exhaust gas as the hot air at the kiln tail of the pulverized coal system for drying, thereby reducing the moisture content of the pulverized coal, increasing the calorific value of the pulverized coal, and reducing the ringing problem of the pulverized coal preparation system. After the system of the utility model utilizes the cyclone dust collector to perform the initial separation of the dust in the exhaust gas, it connects the dust collector behind the main pipeline of the No. 1 induced draft fan for secondary dust collection, and utilizes the underground pipeline to let the waste heat exhaust gas reach the pulverized coal system as the hot air at the kiln tail, and enters the pulverized coal system for recycling.

[0013] The waste gas treatment device of the utility model has strong operability and safety. The system can quickly and effectively reduce tail gas impurities and harmful gases, and reduce pollution to the environment. At the same time, the gas treatment method of the utility model is not only low-cost, but also can recover part of the heat energy in the production process, save energy, and reduce production costs. The central control room of the utility model can control the amount of hot air given to the kiln head in the coal powder system to reduce safety hazards. The utility model is reasonably designed. Compared with the existing direct induced draft fan into the bag dust removal tank, the utility model has the characteristics of good heat utilization at the kiln tail and good waste gas recycling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the utility model system.

[0015] In the figure, 1 represents the kiln tail preheater, 2 represents the cyclone dust collector, 3 represents the induced draft fan 1, 4 represents the dust collector 1, 5 represents the motor, 6 represents the raw coal drying hot air blower, 7 represents the ball mill, 8 represents the powder classifier, 9 represents the dust collector 2, 10 represents the large bag dust collector, 11 represents the induced draft fan 2, 12 represents the desulfurization tower, and 13 represents the exhaust gas emission chimney. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with specific implementation methods. The specific implementation methods are further descriptions of the principles of the present invention and do not limit the present invention in any way. Technologies identical or similar to the present invention do not exceed the scope of protection of the present invention.

[0017] Combined with the attached pictures.

[0018] As shown in the figure, the rotary kiln tail exhaust gas collection, treatment and utilization system of the utility model is arranged at the rotary kiln tail, and the exhaust gas pipeline outlet of the rotary kiln tail is connected to the kiln tail preheater 1; the outlet of the kiln tail preheater 1 is connected to the cyclone dust collector 2, and the outlet of the cyclone dust collector 2 is connected to the induced draft fan 3, and the outlet of the induced draft fan is connected in parallel with the bag dust collection mechanism and the underground dust collection mechanism; wherein, the bag dust collection mechanism is composed of a large bag dust collector 10, an induced draft fan 11, a desulfurization tower 12 and an exhaust gas emission chimney 13 connected in sequence; the underground dust collection mechanism is composed of a dust collector 1 4, a motor 5, a raw coal drying hot air blower 6, a ball mill 7, a powder classifier 8 and a dust collector 2 9 connected in sequence.

[0019] As shown in the figure, the kiln tail preheater 1 is a vertical preheater, which allows the flue gas waste heat to be directly transferred to the kiln system, and the flue gas temperature can be reduced to below 270°C, recovering the tail gas heat and reducing the load for the subsequent cyclone dust removal. After passing through the cyclone dust collector 2, the gas discharged from the flue of the kiln tail preheater 1 can be separated and settled for the first time, which can quickly and effectively reduce the tail gas impurities and harmful gases to a certain extent.

[0020] As shown in the figure, the rear end of the outlet of the induced draft fan 3 is connected in parallel with an underground dust collecting mechanism, which is composed of a dust collector 4, a motor 5, a raw coal drying hot air blower 6, a ball mill 7, a powder selector 8 and a dust collector 2 9 connected in sequence. The underground dust collecting mechanism can collect dust and impurities in the tail gas of the kiln for a second time, further reduce the dust and impurities in the tail gas of the kiln, and improve the safety of coal powder preparation; at the same time, a raw coal drying hot air blower 6 is set at the outlet, and the temperature of the raw coal drying hot air blower 6 is between 150℃ and 200℃. The raw coal is dried by the raw coal drying hot air blower 6 to reduce the moisture content of the raw coal. After the dried raw coal enters the ball mill 7, it is ground and crushed under high temperature and high pressure. After being screened by the powder selector 8, the coal powder is supplied to the kiln head of the rotary kiln through a pipeline for combustion, and the tail gas enters the dust collector 2 9; the dust collector 2 9 mainly uses a pulse bag dust collector for dust collection, which meets the national emission standards.

[0021] As shown in the figure, the induced draft fan 1 3 is also connected in parallel with a bag dust collection mechanism, and the underground dust collection mechanism is composed of a large bag dust collector 10, an induced draft fan 2 11, a desulfurization tower 12 and an exhaust gas emission chimney 13 connected in sequence. The large bag dust collector 10 can capture fine, dry dust, and after passing through the filter material, the dust is retained, so that the gas can be purified. Through the high-power induced draft fan 2 11, it enters the desulfurization tower 12. Since the coal powder enters the rotary kiln and burns, a certain amount of sulfide will be generated. The desulfurization tower can absorb and decompose the sulfide in the flue gas, mainly sulfur dioxide, and the emission meets environmental protection requirements, reducing pollution to the environment, and then it is discharged through the exhaust gas emission chimney.

[0022] The utility model discloses a rotary kiln coal powder preparation workshop kiln tail exhaust gas collection and treatment utilization system with a bag dust removal mechanism and an underground dust collection mechanism in parallel. The rotary kiln tail exhaust gas is cooled by heat exchange in the kiln tail preheater and dusted by the cyclone dust collector before entering the large bag dust collector and the desulfurization tower for discharge; at the same time, the underground dust collection mechanism in parallel utilizes the treated kiln tail exhaust gas to dry the raw coal feed of the coal powder preparation workshop, effectively reducing impurities and dust in the exhaust gas, drying the raw coal, reducing the energy consumption generated by the raw coal with a large moisture content entering the coal powder preparation, and effectively utilizing the exhaust gas heat energy.

Claims

1. A system for collecting, treating and utilizing waste gas at the tail of a rotary kiln coal powder preparation workshop. The outlet of the waste gas pipeline at the tail of a rotary kiln is connected to the preheater at the tail of the kiln; the system is characterized in that: The outlet of the kiln tail preheater is connected to the cyclone dust collector, the outlet of the cyclone dust collector is connected to the induced draft fan 1, and the outlet of the induced draft fan is connected in parallel to the bag dust removal mechanism and the underground dust collection mechanism; The bag dust removal mechanism is composed of a large bag dust collector, a second induced draft fan, a desulfurization tower and an exhaust gas emission chimney connected in sequence; The underground dust collecting mechanism is composed of a dust collector 1, a motor, a hot air blower, a ball mill, a powder classifier and a dust collector 2 which are connected in sequence.

2. According to claim 1, the system for collecting, treating and utilizing waste gas at the kiln tail of a rotary kiln coal powder preparation workshop is characterized in that: The bag dust removal mechanism and the underground dust collection mechanism inlet connected in parallel to the induced draft fan outlet are respectively provided with an openable and closable inlet gate.

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