Advantages of roller distributorsEdit Broadcast The disadvantages of the above-mentioned pendulum-type distributor can be eliminated by using the roller-type distributor for distribution. Roller distributor is the equipment used in metallurgical sintering plants and pelletizing plants. It is characterized by rolling and beating on the rolling rollers, and the material flow is loose and uniform. During the rolling process, the raw balls play the role of re-granulation, so that the raw balls are compacted again, and the internal moisture penetrates into the surface after compaction. That is to say, the formation of water surface is helpful to the improvement of the air permeability of the material layer, and the quality of the green ball is further improved, which provides favorable conditions for the drying operation to achieve high quality and high yield [1] . Editing of technical specifications for roller spreaders The roller distributor is composed of parallel rollers, which are driven by staggered fixed gears. The driving direction of the rollers is the same and is driven by two sets of driving devices. The technical specifications are: L×W 2420×2150mm Roller diameter 108mm Number of rollers 22 groups Roller gap 2mm Roller speed 118 rpm Installation inclination 3° Production capacity 140 tons Motor power 2 x 5.5 watts The greater the number of rollers, the better the uniformity of the cloth and the better the regranulation of the green pellets. According to the specific situation, the number of rollers should be more than 16 groups. Using the roller distributor, due to the improved air permeability of the material layer, the thickness of the material layer is increased from 150-180 mm to 220-240 mm, the production capacity is increased by 25%-30%, and the quality of pellets is also improved accordingly.

The distributor consists of a receiving hopper and its transmission device, a material clock and its lifting device, and a volute-shaped distributor. Receiving hopper and its transmission device The receiving hopper is in the shape of an inverted truncated cone, welded by steel plates and lined with wear-resistant lining plates, and is supported on the rollers on the top of the kiln. The small bevel gear of the transmission device meshes with the large bevel gear fixed at the lower part of the receiving hopper, and through the motor, brake and reducer of the transmission device, the receiving hopper and the worm-shaped distributor are driven to rotate together, and the angle of each rotation is different. , Executed by the master controller, generally running continuously in the order of 15°, 90°, 180° and 270°, after 6 cycles, it can be covered for a week, and a better cloth effect can be obtained. Feed clock and its lifting device The material bell is made of cast steel, and it is required to fit with the lower mouth of the receiving hopper and play a sealing role. The material bell rod is subjected to the impact and wear of the material, and a replaceable protective rod sleeve is installed on it. When the material clock is in place, it plays a sealing role, and when it falls, it plays a role of dividing the material. Its lifting stroke can be adjusted, and the actuator is divided into two types: electric and pneumatic control. The electric lifting mechanism is realized by the master controller through the transmission device, and the pneumatic lifting mechanism is adjusted by the cylinder stroke. CR-α Angle Calibrator for Measuring a Angle of Distributor With the rapid development of the metallurgical industry, as an important part of the iron and steel smelting process, the smelting furnace has also undergone several major changes. From a small blast furnace of 100m3~300m3 to a large blast furnace of 1750m3~3800m3 and even to a large blast furnace of 4200m3, from the double-material bell top to the bellless top that has been widely used.

Blast furnace hot blast stoves can be divided into two types of regenerative hot blast stoves: regenerative type and heat exchange type according to their working principles. According to the combustion method, it can be divided into top combustion type, internal combustion type, and external combustion type. Increasing the hot blast temperature of the hot blast stove is the key technology of blast furnace strengthening smelting. How to improve the wind temperature is the direction of the long-term research of the industry insiders. The common method is to co-fire high-calorific value gas, or increase the heat exchange area of ​​the grid bricks of the hot blast stove, or change the material and density of the grid bricks, or change the shape of the heat storage body (such as heat storage balls), and use various methods. and combustion air preheating. Regenerative lattice brick hot blast stove is the most commonly used form of hot blast stove in modern blast furnaces, especially large blast furnaces. Advantages: high heat exchange temperature, high heat utilization rate, large working air volume, suitable for large blast furnace production needs. Disadvantages: large volume, large floor space, high purchase cost. The heat exchange hot blast stove mainly uses the high temperature resistant heat exchanger as the core component. This component cannot use the metal heat exchanger, but only the high temperature resistant ceramic heat exchanger. The blast furnace gas is fully burned in the combustion chamber. The hot air passes through the heat exchanger to exchange the heat for the fresh cold air, which can make the fresh air temperature reach more than 1000 degrees. Advantages: high heat exchange temperature, high heat utilization rate, small size and low purchase cost. Modern hot blast stove with combustion air preheating using a preheating stove Disadvantages: The heat exchange temperature is not as high as that of the regenerative type, and the scale of use is small

Based on the actual situation of the site, the preheating furnace is reconstructed according to the defects in the original design and manufacturing. The specific modifications are as follows. (1) The medium in the furnace tube in the convection section is changed from “oxygen-steam” to “steam”; in order to avoid the adverse effects on the furnace tube caused by abnormal working conditions during startup and shutdown, and to ensure the safe and stable operation of the device, the furnace tube in the convection section is operated. The temperature is designed and selected according to the operating condition of 500 ℃, 340H is selected, and the furnace tube of the convection section is overall updated with new materials. (2) The 4 burners of the preheating furnace were replaced, and the combustion-supporting air was changed from the original forced air supply to the mode of interlocking and automatic switching of self-priming and forced induction air; Heater, recover the waste heat of the flue gas of the preheating furnace, increase the temperature of the combustion air, and reduce the consumption of the fuel gas of the preheating furnace. (3) Change the oxygen process, that is, the preheating furnace does not preheat oxygen. The improved system flow is as follows: after the steam is preheated in the convection section of the preheating furnace, it is mixed with oxygen at the entrance of the reformer burner and then enters the reformer. (4) Since the leakage of the boiler water heat exchange tube in the convection section is difficult to repair, the preheating furnace short-circuits the boiler feed water pipe from outside the furnace, and blocks the boiler feed water inlet and outlet headers. In this transformation, the boiler feed water heating section of the original preheating furnace convection section was cancelled. (5) In order to increase the safety factor of the preheating furnace operation, the burner is equipped with a permanent light, which eliminates the potential safety hazard that the fuel gas will accumulate in the furnace chamber and mix with air to form explosive gas after the instantaneous flameout in the furnace chamber.

(1) Oxygen enters the reformer after being preheated in the convection section of the preheating furnace, and coke oven gas enters the reformer after being preheated in the radiation section of the preheating furnace. The process of preheating coke oven gas and pure oxygen in one preheating furnace at the same time does not have the same design in domestic methanol plants of the same type. However, there is an intrinsic safety problem in this design, that is, once a large amount of leakage occurs in the oxygen coil of the preheating furnace, or a small amount of leakage occurs without timely detection and shutdown measures, high-temperature oxygen will lead to major accidents in the preheating furnace; more seriously, If the oxygen pipeline in the preheating furnace leaks a lot, and the high temperature gas at about 1000 ℃ in the reformer flows back into the oxygen pipeline, it will also cause a secondary accident, and the consequences will be more serious. The two previous oxygen pipeline leaks were found in time, handled correctly and decisively, to avoid the occurrence of vicious accidents. (2) In the original design of the preheating furnace, there is no "permanent light". After the fuel gas leaks in the furnace or the flame is instantaneously extinguished, the fuel gas will inevitably accumulate in the furnace and mix with the air to form an explosive gas. (3) The combustion-supporting air of the preheating furnace is designed to be forcedly supplied by the air blower. Once the combustion-supporting air blower fails, the combustion-supporting air supply of the preheating furnace must be stopped. At this time, the preheating furnace must quickly cut off the fuel gas and extinguish the flame, otherwise it will inevitably cause A large amount of fuel gas accumulates in the hearth of the preheating furnace, which is very likely to explode, and after the preheating furnace is turned off, the coke furnace gas, steam and oxygen cannot be preheated, and the heat required for the conversion reaction in the subsequent process cannot be provided. Parking is required. Therefore, the combustion-supporting air of the preheating furnace is only designed to be forced air by the blower, which has inherent safety hazards. (4) The flame detection protection system is not set in the design of the preheating furnace. After the preheating furnace is extinguished, the fuel gas cannot be automatically interlocked and cut off, which will inevitably lead to a large accumulation of fuel gas in the furnace chamber of the preheating furnace, which is very likely to explode.

(1) Design technical data errors. In the design of the preheating furnace, in the process flow and equipment list, it is clear that the medium in the furnace tube of the convection section of the preheating furnace is "oxygen-steam". The medium in the section furnace tube is "steam", the process drawing of the preheating furnace does not match the content of the medium in the equipment drawing, and the technical data of the preheating furnace equipment is wrong. (2) The use level of equipment materials is low. According to the inspection results, one of the three "oxygen-steam" pipes in the preheating furnace has leaks in many places. After analysis, it is found that the material used for the "oxygen-steam" coil is 304. Compared with OCr18Ni10Ti and 316, 310 and other materials, the tendency of intergranular corrosion is stronger at temperatures above 425 ℃, and 600 to 700 ℃ belongs to the intergranular corrosion of 304. In the area, the corrosion rate Z is fast, and steam + oxygen belongs to the state of wet oxygen, which can damage the Cr2O3 anti-oxidation film at high temperature and has a strong oxidizing effect on 304. After communicating with many design units, it is confirmed that 304 material is not suitable for long-term use in high temperature and high oxygen environment, that is, for the operating conditions of the preheating furnace, the material selection level of the "oxygen-steam" coil is low, which cannot meet the requirements for use. Require. (3) The equipment structure design is unreasonable. The preheating furnace is a vertical cylindrical tube furnace, all of which are designed with a coil structure. From the perspective of operation, its thermal efficiency is not high, only 75%, and the furnace tube must be inspected and overhauled when it breaks down. The furnace is disassembled, the repairability is poor, and the maintenance is very difficult.