Exploration and treatment of the occurrence of ash removal equipment

The operating conditions were analyzed in depth and effective pre-control measures were taken. At the same time, in the work of saving ash and slag system to save energy and reduce pollution, we have summed up a set of solutions to achieve system optimization by adjusting the operation mode of equipment, and achieved a transition from experience type to scientific one. The following sections on electric dust removal, dry ash removal, air compressor, and slag removal are further discussed from the perspective of improving equipment reliability and economy.

1Electric dust removal system 1. 1 Overview of the dust collector The second phase of each furnace is equipped with 2 sets of 2FAA5 40M - 4 88-150 double-chamber five-field electrostatic precipitator. The dust collecting plate of each electrostatic precipitator is in the form of a C-shaped anode plate, and a spur line type cathode line is used in one electric field, two electric fields and three electric fields, and a spiral type cathode line is used in four electric fields and five electric fields. The electric field height is 15m, and each electric field is powered by two sides. There are 40 rectifier transformers in each furnace. The electric precipitator body is installed on the top of the 4. 5m dry ash removal plant, and is centrally controlled, and the rectification is arranged on the top of the electrostatic precipitator at 28. 9 m. The technical parameters of the electric elimination are as follows: the amount of flue gas treated, 4 429 454 (4 520 705 check) m 3 /h; the dust content at the inlet, 18. 9 ( 23. 1 check) g/m 3; the flue gas in the electric field Flow rate, 1. 17 m / s; smoke flow through electric field time, 17. 16 s; flue gas temperature, 150; body resistance, 200 Pa; body air leakage rate, 2%; dust removal efficiency, 99. 7%; The furnace is equipped with 60 anode and cathode rapping reducers.

The high voltage control power supply equipment is GGA JO2- 1. 8A / 72kV type power supply. The rated voltage is 72 kV and the rated current is 0.1 A; each electrostatic precipitator is equipped with 10 sets. The silicon rectifier transformer is placed in a high position, and the high voltage power supply is introduced into the electric field by the high voltage isolation switch at the top.

1. 2 Electrostatic precipitator equipment failure and treatment During the more than one year of operation, the main defects of the ESP equipment are the damage of the cathode rapping reducer bearing and the short circuit in the individual electric field of the electrostatic precipitator. Electrostatic precipitator vibration bearing reducer bearing damage is

The main reason found during the scheduled maintenance of the 4-machine shutdown was due to poor lubrication caused by lack of oil after the bearing grease leaked. The pre-control measures are regular inspection and timely oil injection; high-quality high-temperature DHY grease is selected; anti-freezing measures (such as intermittent transmission) during the winter shutdown of electric dedusting equipment are formulated. The short circuit of the electric dust removal electric field is caused by electrical causes and has been completely solved.

1. 3 Optimized management of the electric dust removal system Strengthen the operation and maintenance management of the electrostatic precipitator, in order to ensure that the dust removal efficiency of the electrostatic precipitator reaches 99.7%, on this basis, the optimization scheme for the operation of the electrostatic precipitator is formulated: (1) Rectifier transformer In normal operation, it is set to operate under the automatic spark tracking mode; the insulator ceramic shaft, porcelain sleeve heating, and ash bucket heating are put into operation under automatic temperature control; in the case of partial oil injection of the boiler, the anode and cathode rapping are put into continuous rapping and oiling. After the end, the cycle operation mode is entered.

(2) Strengthen the maintenance and management of the online monitoring device for soot, ensure the input rate of the soot online monitoring device and the accuracy of the data. The operating personnel timely adjust the operating parameters of the electrostatic precipitator and the interval between the vibrations according to the monitoring data to ensure the low concentration of atmospheric pollutants. Emission Standards.

According to the dust concentration measured by on-line monitoring of flue gas, check the actual value of the ash specific resistance, and study the feasibility of stopping the second phase of the five electric fields (an electric field of 8 rectifier transformers, and the power saving effect is considerable).

(3) In order to ensure the energy-saving and efficient operation of the electrostatic precipitator, not only achieve energy-saving purposes but also meet environmental protection emission requirements, manual adjustment of intermittent power supply, shutdown electric field and intelligent control can be used in combination, so that the power consumption of the electrostatic precipitator high-voltage power supply is higher than The daily spark tracking power supply method has been greatly reduced. So far, the energy saving effect is obvious.

In May 2008, under the guidance of the technical staff of Xi'an Thermal Power Research Institute, the performance test of two sets of electric precipitators was completed.

The efficiency of the electrostatic precipitator, the body resistance, and the air leakage rate all meet the design requirements, which is an affirmation of the optimized operation of the electrostatic precipitator.

2 double casing ash conveying system 2. 1 dry ash removal equipment overview Phase II Each furnace electric precipitator body is equipped with 40 ash hoppers, each ash bucket is equipped with a dry pump and Other dry ash removal equipment, there are 7 independent Double casing conveyor unit. The ash round section and the pneumatic dome feed valve in the ash bucket are concentrated to the transfer pump, and each unit sends the collected dry ash from the compressed air to the ash warehouse through three 650 m double casings according to the full material signal, and the gas is exhausted. It is separated into the atmosphere by a bag filter placed on the top of the ash bank. The system uses automatic program control and allows for remote manual operation and local manual operation.

2. 2 Failure of pneumatic conveying ash and pre-control measures The multiple failures of the dry ash removal system of the two units are mainly concentrated on the balance valve of the pump, the bursting of the PU pipe of the control source, the damage of the seal of the pneumatic feed valve, the failure of the seal, etc. The problem. The balance valve was originally installed as a DN65 double gate valve. Due to the frequent accumulation of ash between the gates, the valve is stuck, which makes the switch inflexible and affects the stability of the program-controlled operation of the system. It has been completely transformed into a DN65 disc valve and has been operating well for half a year. The main reason for the bursting of the PU tube is that its own quality is not enough, and the operation of the dry ash chamber is too high. The pre-control measures were taken to convert a part of the PU tube into a copper tube and the other part to replace the high-pressure hose while reducing the room temperature. The pneumatic feed valve seal has been adjusted to improve the installation quality, which basically eliminates the repeated failure of the seal.

2. 3 double casing ash conveying system problems and solutions The dry ash removal system uses the ash-gas ratio as the energy-saving indicator of the team, and the ash-free professional team has established an energy-saving electronic form. The running team has statistics on the indicators, each class has adjusted its own operation mode, and increased energy-saving analysis and other items. Based on the test data, the system efficiency is improved by optimizing the operation mode. Specific optimization measures should be implemented in conjunction with air compressors.

In the past one year of operation, the leakage point of the double casing ash pipeline mostly occurred in the joint surface of the pipeline connection flange, because it is very laborious to replace the new asbestos gasket, and some flange sealing lines have been damaged. Take 2 flange welding methods to deal with. At the same time, the flange joint pipe sections should be retightened with bolts to avoid leaks. The direct wear and leakage points on the pipeline have not appeared in the operation, which indicates that the adjustment of the ash-gas ratio and the control of the conveying speed are very effective.

3 compressed air system 3.1 Turbine air compressor introduction The second phase of the ash removal system is equipped with 8 sets of MM 250 screw air compressors. The main pipe is used to provide a gas source operation mode. To ensure compressed air quality, each air compressor is equipped with a dryer and a micro-thermal regeneration drying tower. The equipment parameters are as follows: air compressor rated displacement / ( m 3 m in - 1) 42 air compressor rated exhaust pressure / M Pa 0. 75 cooling method water cooling (industrial water) cooling water / (m 3 m in - 1) 3.2. Multiple failures of air compressors Over-temperature operation of air compressors is a major failure. After many treatments, the main reason is that the cooling water quality is not closed, causing the screw machine filter to become clogged and the water flow rate to decrease. The cooling effect is worse. The improvement of water quality is to solve the problem by adding an orifice plate to remove the debris and then installing a cleaning filter on the main cooling water channel.

3. 3 Energy-saving and consumption-reducing air compressor optimization operation scheme The optimized combination of air compressor and dry ash removal electric field operation mode is an effective economic and energy-saving way for ash removal system. According to the boiler load and the ash volume per unit time, the number of air compressors is determined, and the setting of the program control operating parameters of the pump is adjusted to shorten the no-load running time of the air compressor, thereby reducing the air consumption and reducing the power consumption. By clearly seeing the effective cooperation between the air compressor and the pump operation mode, the program-controlled operating parameters are manually set, and the adjustment is made on a regular basis. The trial performance has been good for half a year.

4 slag removal system 4.1 dry slagging system overview The slag in the cold ash hopper of the second stage boiler is collected by the steel belt machine through the crusher into the dry slag slag tank, and sent to the storage through the 700m slag double casing through pneumatic conveying. Slag bin. Each furnace is equipped with a slag bin. Before the boiler delivers the dry slag into the slag bin, it can enter any of the two slag bins through the switching valve on the pipeline; each slag bin has a pulse bag. The dust collector and a vacuum pressure release valve have two rotary feeders and a slag humidification mixer at the bottom of each slag storage bin. The dry slag is sent to the open pit backfill pit through the slag mixer through the belt and ash. The belt conveyor system is simple.

4. 2 Insufficient design and improvement of slag removal system (1) Insufficient indication of slag pump level gauge can not correctly reflect the position of ash bucket; dry slag system slag bin level meter often mis-signs, resulting in system control disorder. This problem is solved by re-selection of the level gauge and change of the installation position.

(2) The dry slag is selected from the pipe with a diameter of 250mm. Since the design of the slag bin bag filter is small (the treatment air volume is 8 640m 3 /h), the slag silo vacuum release valve frequently moves outwards to cause ash and environmental pollution. serious. The ash-removing personnel skillfully utilize the large-diameter pipe

24 slag silos are connected, and the operation is controlled by a single silo slag. At the same time, two bag dust collectors are used to operate, which solves the problem of ash ash in the slag bin and avoids pollution discharge.

4. 3 The main defects of the slag removal system and the repeated defects of the slag removal system. The slag pump and the rotary feeder installed under the slag bin are often stuck, which occurs from time to time after the start of the furnace, and the maintenance personnel are added for maintenance. Difficulty, this is mainly caused by debris such as iron wire and welding rods falling inside the furnace. Only after the equipment has been manually cleaned can it be operated normally. Late

The 3 machine has a magnetic rod and a pull iron net attached to the head of the steel belt machine, and the effect is good. It is recommended to use the gray iron selection technology to install a magnetic de-ironing device to completely remove the debris (ironware) in the slag to ensure the stable operation of the dry slagging system.

The failure frequency of the shaft seal of the slag pump feeder is relatively large, which has caused different degrees of damage to the shaft diameter and the bearing. How to ensure efficient sealing and long-cycle trouble-free operation of the feeder is an urgent problem to be solved.

5 Conclusions The second phase ash removal system of Inner Mongolia Yimin Power Plant has left many defects due to design and installation, and has been gradually solved. Relatively speaking, Yimin Phase I ash removal system has refined the system flow, which makes the reliability of ash removal equipment improved, the degree of automation is improved, and the maintenance and repair volume is greatly reduced. The quality of the system is directly related to the quality of the power plant environment. It is the efficient operation of the ash removal system that achieves two major production goals: First, the mass concentration of soot in the flue gas is 23 mg/m 3 (the national standard is not more than 600 mg/m 3 ), which is far lower than the current country. The prescribed emission standards; the second is that the ash generated by power generation does not fall to the ground, and the belt is directly returned to the open pit mining area. This paper comprehensively summarizes the operation and management of the ash removal system in the past one year. The purpose is to find out the existing problems, improve the working methods, and tap the energy saving potential to ensure the long-term safe and economic operation of the unit. I hope to provide some reference and reference for the design and consumption reduction of the same type of unit ash removal system.

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