Some discussion and research on China's new technology and new products on air compressors for steam turbine side Hu Jinsheng (Shenhua Guohua Beijing Thermal Power Branch Power Generation Management and Operation Department, Beijing 100000) The safe operation of units 1 and 2 has very important significance. The failure of the air compressor failure will result in non-stop accidents for the 1 and 2 units. In this paper, the safe operation of the instrument air compressor is discussed in detail. Many very suggestive questions have been raised. It has been sought to be better applied to production practice. Guohua Beijing Thermal Power Branch currently has three TZW50-15-MKU130-L-1000VSZ air compressors supplied by ABB. The compressed air outlet pipes of three air compressors are connected in parallel, which is the two-unit steam turbine side. Pneumatic adjustment doors provide a source of power. The air compressor is a dry piston type, which works in two stages. The maximum pressure of the first-stage cylinder is 4 bar, the maximum allowable over-pressure of the second-stage cylinder is 11 bar, and the two-stage separator is equipped with a straight-through spring safety valve. Some important parameter values ​​in normal operation are as follows: the normal air pressure range is 0.75~1.05MPa, the protection value is 0.48MPa, the safety door action value is I.IMPa, the low pressure start air compressor is 0.8.Mpa, and the stop pressure value is 1.06MPa. Through actual observation, it is known that any air compressor starts to work after running for about 30 seconds. The time for pumping up to 1.06 MPa is about 10 minutes, and the time for the pressure to drop to 0.80 MPa is about 15 minutes. The set values ​​of the three air pressure switches are different. 1 The starting pressure of the air compressor is now 0.75, the stopping pressure is 1.0, the starting pressure of the air compressor is 0.73, the stopping pressure is 0.97, and the starting pressure of the air compressor is 3. It is 0.80, and the stop pressure value is 1.06. 3 Some functions about the instrument air compressor 3.1 About the start/stop function The air compressor start/stop is realized by the air pressure switch. Regardless of whether the control handle is cut to the manual operation (2) position or the continuous operation (1) position, the start/stop of the air compressor is controlled by the air pressure switch. When the air main pipe pressure is reduced to the lower limit, the air compressor starts to press, and when the air pressure reaches the upper limit, the air compressor stops running. When the three air compressors are operated manually, the start/stop of the air compressor is controlled by the respective air pressure switches. Therefore, there is a difference in the pressure values ​​at which the air compressor starts/stops. When three air compressor control handles are simultaneously cut in the running position (manual operation (2) position or continuous operation (1) position), the three air compressors share one air pressure switch. The start/stop of the three air compressors is controlled by this air pressure switch. 3.2 About the sequence start and rotation operation function The three air compressor control handles are cut to the sequential operation (1) position or the manual operation (2) position, and the time switch is turned on/off according to the preset program. The contact point controls the switching of the step relay contact, the intermediate relay has different working states, the arrangement and combination of the contact groups, and the different air compressor control circuits are turned on, so that the starting of the air compressor is sequentially arranged, and the three air compressors are sequentially arranged. Rotate operation. Put the air compressor control handle in sequential operation: (1) mode or manual operation (2) mode. When the air compressor is working, the air main pipe pressure cannot be increased, and when it continues to decrease, the air pressure switch will be another. An air compressor starts the auxiliary operation. If the air main pipe pressure cannot be increased, the third air compressor will automatically start the auxiliary operation until the air main pipe pressure returns to the upper limit set by the air pressure switch. In order to achieve the auxiliary operation function, at least two air compressor control handles must be cut in the sequential operation (1) position or the manual operation (2) position. 3.4 Protection air compressors for instrument air compressors are equipped with three types of protection: low pressure lubrication, cooling water temperature protection and motor overload protection. The control panel is equipped with a fault greater than 40 degrees. The oil pressure protection intermediate relay, the water temperature protection intermediate relay and the overload protection contact string are connected in the motor control circuit, and one of the protection actions can cut off the control power of the motor and stop the air compressor. And start the control panel fault indicator, and send a signal to the remote control room through the common fault contact, prompting the on-duty personnel to go to the site for inspection and processing. 4 Some problems in the operation of the instrument air compressor When the air compressor is out of operation, its control handle is cut to the 0 position, so that the sequence selection circuit is disconnected. Therefore, no matter whether the other two air compressor control handles are cut in the sequential operation (1) position or the manual operation (2) position, the other two air compressors can only realize the start/stop mode operation of the respective air pressure switch control. No longer rotate in sequence. This will cause the air compressor with a high setting to start frequently, and the air compressor with a low setting will never start. If the air compressor is overhauled for a long time, the running air compressor will continue to turn down, which is not conducive to the safety of the equipment. This problem occurs during the air compressor repair period. The instrument uses an air compressor to cool the industrial water of the 1 and 2 machines. In the summer, all the coolers on the machine side use industrial water. This will cause the pressure of the industrial water to be very low, sometimes as low as 0.2MP. The regulations require that the industrial jellyfish tube pressure should be maintained at not less than 0.3MP (the air compressor is not less than 0.25MP). If it is lower, the cooling effect of the air compressor will become poor and the oil temperature will rise. When it is greater than 66*, the air compressor will protect the trip. This is not conducive to the normal operation of the air compressor. This will also affect the safety of the unit. 4.3 The problem of high backwater pressure in industrial water and poor returning water is an old problem. It has also been plagued for many years. The high backwater pressure will cause the backwater of the air compressor to not take the heat very well. The phenomenon that the temperature of the air compressor oil rises. 5.1 Regarding the first question, I think this requires the support of the thermal workers. At the same time, it needs the help of the electricians to modify the starting and stopping values ​​of the air compressor, and also to change the interlocking conditions of the air compressor. So that the air compressor can really do the rotation start. 5.2 Regarding the low industrial water pressure in summer, the operating personnel are required to adjust the industrial water in time to meet the water requirements of the air compressor. If it is not enough, it is necessary to consider switching another unit belt or adding a new standby water source. 5.3 Regarding the poor return water, the air return pipe of the air compressor is changed from the original back to the water tank of the machine with the zero meter of the original zero, and the water tank is directly drained from the 2 machine. When an air compressor runs, the cooling water source When using 1 machine of industrial water, when the cooling water pressure at the remote 3 air compressor is not less than 0.2 MPa, the cooling water temperature of the air compressor is about 30*C (the same applies when using the cooling water source of 2 machines) It can guarantee safe operation. However, from the safety considerations, it is decided not to limit the cooling water gate of the air compressor, but the pressure at the far end cannot be lower than 0.2 MPa. The operation safety problem of the air compressor for the instrument is safe and stable to the two unit units. The equipment defects of the press should be eliminated in time to ensure that the three air compressors are in a good standby state at any time. Machinery Brackets ,Metal Brackets ,Metal Shelf Brackets,Steel Brackets Ningbo Metal Sharing Supply Chain Management Co., Ltd , https://www.sheetsharing.com