Lime kiln feeding system

Abstract

The utility model discloses a feeding system for a lime kiln, which is used for automatically batching and feeding for a vertical lime kiln and comprises a limestone conveying mechanism, a pulverized coal conveying mechanism and a mixing and distributing mechanism, the limestone conveying mechanism comprises a limestone bin, a drum screen, a limestone vibrating feeder and a limestone metering hopper which are arranged in sequence; the pulverized coal conveying mechanism comprises a coal bunker, a coal vibrating feeder, a CaO hopper, a coal belt conveyor and a coal metering hopper which are arranged in sequence; the mixing and distributing mechanism comprises a mixing belt conveyor, a raw material elevator and a fixed umbrella type distributor; the lime kiln feeding system adopts the limestone conveying system and the medium conveying system which are respectively arranged, each conveying system is provided with a screening crushing mechanism and a metering mechanism, feeding is performed through the elevator after conveying and mixing are performed through the conveying belt, the feeding efficiency is high, feeding is more uniform, a CaO adding and mixing device is specially arranged, the structure is simple, complex equipment does not need to be added, and the production cost is reduced. And the firing components and environment of the lime kiln are improved, and more energy-saving and environment-friendly effects are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of lime kiln design, relates to the design of a lime kiln auxiliary system, and specifically relates to a lime kiln feeding system. Background Art

[0002] The existing lime kiln feeding system mainly crushes and screens limestone to meet the production requirements, and then transports it to the ore storage bin; coal is crushed and screened and then transported to the fuel storage bin. Limestone and coal are transported by conveyors and automatically recorded and weighed, and then put into the feeding hopper according to a certain ratio, lifted to the kiln top by the elevator, and evenly added to the vertical kiln through the distributor.

[0003] This feeding system has high limestone production and is widely used in metallurgy, construction, chemical industry and other fields. However, it has the following disadvantages: raw coal and limestone contain a certain proportion of water. If they are directly mixed into the distributor and calcined in the kiln, a large amount of heat energy will be taken away due to the drying of the water, which is not conducive to energy increase and consumption reduction. At the same time, due to the incomplete combustion of coal powder, a large amount of gas that affects the environment is discharged, which is not conducive to environmental protection. Summary of the invention

[0004] The utility model discloses a lime kiln feeding system in view of the deficiencies in the prior art. The utility model aims to provide a lime kiln feeding system with higher efficiency and better environmental protection.

[0005] The utility model is realized by the following technical solutions:

[0006] A lime kiln feeding system, the feeding system is used for automatically batching and feeding a vertical lime kiln, characterized in that it includes a limestone conveying mechanism, a coal powder conveying mechanism and a mixing and distributing mechanism;

[0007] The limestone conveying mechanism includes a limestone bin, a drum screen, a limestone vibrating feeder, and a limestone weighing hopper which are arranged in sequence; the limestone bin is used to receive limestone, and a drum screen is arranged at the outlet end of the limestone bin. The limestone enters the limestone vibrating feeder after being screened by the drum, and the limestone vibrating feeder distributes the limestone into the limestone weighing hopper through vibration;

[0008] The pulverized coal conveying mechanism includes a coal bunker, a coal vibrating feeder, a CaO hopper, a coal belt conveyor and a coal measuring hopper which are arranged in sequence; the coal bunker is used to receive the pulverized coal, and a coal vibrating feeder is arranged at the outlet of the coal bunker. The coal vibrating feeder distributes the pulverized coal into the CaO hopper through vibration and mixes it with CaO. The mixed pulverized coal and CaO fall into the coal belt conveyor and are transported to the coal measuring hopper;

[0009] The mixing material distribution mechanism includes a mixing belt conveyor, a raw material elevator and a fixed umbrella-type distributor; the outlet ends of the limestone metering hopper and the coal metering hopper are arranged in front and behind the inlet end of the mixing belt conveyor, and a raw material elevator is arranged at the outlet end of the mixing belt conveyor. The raw material elevator transports the mixed material to the fixed umbrella-type distributor located on the upper part of the lime kiln through the lifting hopper.

[0010] The utility model provides a coal measuring bucket for the coal powder conveying mechanism, and provides two limestone measuring buckets for the limestone conveying mechanism.

[0011] The drum screen is a shaftless drum screen.

[0012] The utility model lime kiln feeding system screens limestone by rolling screen, and through the centrifugal force of the rotating drum and the jigging effect, the impurities are screened out and transported away manually, so as to effectively separate mud and stone, reduce the impurities entering the vertical kiln to produce oxidation, volatilization and other reactions, and affect the product quality. This is an effective way to reduce the loss on ignition of the lime vertical kiln.

[0013] After the coal powder passes through the vibrating feeder, CaO is added and then mixed with limestone, a chemical reaction of CaO+H2O=Ca(OH)2 can occur, which reduces the moisture contained in the limestone and raw coal, stabilizes the thermal efficiency in the kiln body, and reduces heat loss. At the same time, since calcium oxide is added in advance to reduce the moisture in the raw materials, the kiln top temperature is guaranteed to be around 150°C. The existing ordinary vertical kiln top temperature is 200-400°C, and the kiln top temperature indirectly reflects the utilization level of the kiln top temperature. The existing ordinary vertical kiln top has a higher temperature, large heat dissipation, and is not conducive to energy saving.

[0014] Due to the calcination of limestone, the high temperature of CaCO3=CaO+CO2↑, the ventilation at the bottom of the kiln and the exhaust at the top of the kiln will form a protective layer mainly composed of carbon dioxide at the higher part of the preheating zone, and the temperature of the upper layer is lower. When spreading the material, the unreacted calcium oxide can continue to react to reduce the moisture in the mixture. At the same time, the powder Ca(OH)2 generated by the CaO reaction will also react with the SO2 generated by coal combustion to form CaSO3 at room temperature, and CaSO3 will also form CaO in the subsequent calcination high temperature, reducing the emission of harmful gases and being more environmentally friendly and efficient.

[0015] The utility model lime kiln feeding system is equipped with two limestone measuring hoppers and one raw coal measuring hopper, which is more efficient. Theoretically, the lime kiln needs 1.786 tons of limestone to produce one ton of calcium oxide, and 140 kilograms of standard coal are needed to decompose one ton of limestone. By using the automatic control program, the measuring hopper can be effectively used to adjust the proportion and evenly mix the two.

[0016] The utility model adopts a limestone and coal conveying system which are respectively arranged. Each conveying system is provided with a crushing and metering mechanism. The materials are conveyed and mixed by a conveyor belt and then fed by a hoist. The feeding system is provided with different numbers of metering hoppers according to the needs of lime burning, so that the feeding efficiency is higher. The mixed materials are fed through an umbrella-type material distribution structure on the kiln top, so that the feeding is more uniform. At the same time, a CaO adding and mixing device is specially arranged in the coal conveying system, and the CaO hopper is arranged between the coal vibrating feeder and the coal belt conveyor. The structure is simple and there is no need to add complicated equipment. By pre-adding CaO, the lime kiln burning composition and environment are improved, and it is more energy-saving and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the feeding system of the utility model.

[0018] In the figure, 1 represents limestone bin, 2 represents coal bin, 3 represents drum screen, 4 represents limestone vibrating feeder, 5 represents limestone measuring hopper, 6 represents coal vibrating feeder, 7 represents CaO adding hopper, 8 represents coal belt conveyor, 9 represents coal measuring hopper, 10 represents mixing belt conveyor, 11 represents raw material elevator, 12 represents fixed umbrella distributor, 13 represents lime vertical kiln, and 14 represents discharge pipe. DETAILED DESCRIPTION

[0019] 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.

[0020] Combined with the attached pictures.

[0021] As shown in the figure, the lime kiln feeding system of the utility model is used for automatically batching and feeding the vertical lime kiln, including a limestone conveying mechanism, a coal powder conveying mechanism and a mixed material distribution mechanism;

[0022] The limestone conveying mechanism comprises a limestone bin 1, a drum screen 3, a limestone vibrating feeder 4, and a limestone weighing hopper 5 which are arranged in sequence; the limestone bin 1 is used to receive limestone, and a drum screen 3 is arranged at the outlet end of the limestone bin 1. The limestone enters the limestone vibrating feeder 4 after being screened by the drum screen 3. The limestone vibrating feeder 4 distributes the limestone into the limestone weighing hopper 5 through vibration.

[0023] The pulverized coal conveying mechanism includes a coal bunker 2, a coal vibrating feeder 6, a CaO adding hopper 7, a coal belt conveyor 8 and a coal measuring hopper 9 which are arranged in sequence; the coal bunker 2 is used to receive the pulverized coal, and a coal vibrating feeder 6 is arranged at the outlet end of the coal bunker 2. The coal vibrating feeder 6 distributes the pulverized coal into the CaO adding hopper 7 through vibration and mixes it with CaO. The mixed pulverized coal and CaO fall into the coal belt conveyor 8 and are transported to the coal measuring hopper 9;

[0024] The mixing distribution mechanism includes a mixing belt conveyor 10, a raw material elevator 11 and a fixed umbrella-type distributor 12; the outlet ends of the limestone metering hopper 5 and the coal metering hopper 9 are successively arranged at the inlet end of the mixing belt conveyor 10, and the raw material elevator 11 is arranged at the outlet end of the mixing belt conveyor 10. The raw material elevator 11 transports the mixed material to the fixed umbrella-type distributor 12 located on the upper part of the lime kiln 13 through the lifting hopper.

[0025] The finished lime is discharged into the 14 unloading tank after cooling.

[0026] The operation process of the lime kiln feeding system of the utility model is as follows: limestone and coal are unloaded into limestone bin 1 and coal bin 2 respectively. Limestone passes through drum screen 3 to remove impurities, and then passes through vibrating feeder 4 to limestone weighing hopper 5; coal passes through vibrating feeder 6, and then adds CaO hopper 7 for mixing, and then passes through belt conveyor 8 to coal weighing hopper 9. After limestone and coal are mixed in proportion, they pass through mixing belt conveyor 10 and raw material hoist 11 to fixed umbrella distributor 12 to complete feeding.

[0027] The limestone passes through the rolling screen 3, and the impurities are screened out and transported away manually by utilizing the centrifugal force of the rotating drum and the jigging effect, so as to effectively separate the mud and stone, and reduce the impurities from entering the vertical kiln to produce oxidation, volatilization and other reactions, which affect the product quality. This is an effective way to reduce the loss on ignition of the lime kiln.

[0028] After the coal powder passes through the vibrating feeder 6, CaO is added and then mixed with limestone, a chemical reaction of CaO+H2O=Ca(OH)2 can occur, which reduces the moisture contained in the limestone and coal, stabilizes the thermal efficiency in the kiln body, reduces heat loss, and prevents the material from being fluffy due to mutual adhesion caused by excessive moisture. At the same time, since calcium oxide is added in advance to force out the moisture in the raw materials, the kiln mouth temperature does not need to be maintained above 150°C all the time, so the temperature of the calcining zone can also be reduced, effectively avoiding overburning of the product, which not only reduces heat loss but also improves energy utilization.

[0029] The utility model uses limestone to calcine CaCO3 at high temperature = CaO + CO2↑. After the kiln body itself is raised (60m), the fan power is adjusted to form a protective layer mainly composed of carbon dioxide at a higher position in the preheating zone. The upper temperature is lower. When the material is laid, the unreacted calcium oxide can continue to force out the moisture in the mixed material. At the same time, the powder Ca(OH)2 generated by the CaO reaction will also react with the SO2 generated by coal combustion at room temperature to form CaSO3, and CaSO3 will also form CaO in the subsequent calcination high temperature, thus reducing the emission of harmful gases, which is environmentally friendly and efficient.

[0030] After the limestone passes through the limestone metering hopper 5 and the coal passes through the coal metering hopper 9, the materials are simultaneously received by the mixing belt conveyor 10 for proportion mixing, which can be mixed more accurately in proportion, and the proportion can be optimized by using automatic equipment to adjust the proportion. The existing mixing method of only using a distributor to distribute the materials layer by layer or mixing one hopper by one hopper is changed, so that the raw materials are fully uniform.

Claims

1. A lime kiln feeding system, the feeding system is used for automatically batching and feeding a vertical lime kiln, characterized in that: It includes limestone conveying mechanism, coal powder conveying mechanism and mixed material distribution mechanism; The limestone conveying mechanism includes a limestone bin, a drum screen, a limestone vibrating feeder, and a limestone weighing hopper which are arranged in sequence; the limestone bin is used to receive limestone, and a drum screen is arranged at the outlet end of the limestone bin. The limestone enters the limestone vibrating feeder after being screened by the drum, and the limestone vibrating feeder distributes the limestone into the limestone weighing hopper through vibration; The pulverized coal conveying mechanism includes a coal bunker, a coal vibrating feeder, a CaO hopper, a coal belt conveyor and a coal measuring hopper which are arranged in sequence; the coal bunker is used to receive the pulverized coal, and a coal vibrating feeder is arranged at the outlet of the coal bunker. The coal vibrating feeder distributes the pulverized coal into the CaO hopper through vibration and mixes it with CaO. The mixed pulverized coal and CaO fall into the coal belt conveyor and are transported to the coal measuring hopper; The mixing material distribution mechanism includes a mixing belt conveyor, a raw material elevator and a fixed umbrella-type distributor; the outlet ends of the limestone metering hopper and the coal metering hopper are arranged in front and behind the inlet end of the mixing belt conveyor, and a raw material elevator is arranged at the outlet end of the mixing belt conveyor. The raw material elevator transports the mixed material to the fixed umbrella-type distributor located on the upper part of the lime kiln through the lifting hopper.

2. The lime kiln feeding system according to claim 1, characterized in that: The pulverized coal conveying mechanism is provided with a coal measuring hopper, and the limestone conveying mechanism is provided with two limestone measuring hoppers.

3. The lime kiln feeding system according to claim 2, characterized in that: The drum screen is a shaftless drum screen.

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