First, the process conditions and process conditions before the transformation In our own steam production process, there is a key equipment for the temperature reducer, the device will be produced by the steam boiler (without the steam turbine power generation) from 2 . 4 8 MP a 4 3 0 ℃, de-temperature reduction to 0.35Mpa 170 ℃ to meet the company's other steam units Yun needs; the pressure reducing valve on the reducer and water distribution valve for the temperature reduction Compressor factory supporting, model Y45 / Y 1 00-Dg150 double-seat valve and equipment since the company's production has been running for more than 4 years, basically to meet the company's production requirements: But in these 4 years During the operation period, we also found that the equipment has some problems, mainly in the following aspects: ◆ Relief valve leakage is large, especially in the case of steam generated by the steam turbine, under such conditions, the pressure relief valve This is completely shut down, but due to the double-seat valve structure and product quality problems, the valve in the fully closed position, there is still a large amount of steam leakage, resulting in unnecessary energy loss and increase production costs . ◆ Adjustment range is small: from the adjustment characteristics of double-seat valve we can see that the valve adjustment range is relatively small: According to the actual operation of the process point of view, the boiler operating under small load (steam capacity at l0T / h), the decompression The valve is unable to adjust the steam pressure, ie the steam pressure can not be adjusted when the steam flow is less than 10T / h. ◆ low control accuracy, poor stability: pressure reducing valve and the control valve is used with a servo amplifier angle of travel of the electric actuator, the actuator and the valve stem is the use of leverage: servo amplifier model is too old, balanced and The regulation of the stability is too complicated. Due to the industrialized handling of electronic components and devices used in servo amplifiers and feedback boards, the environmental requirements are also high, and the work is unstable in high temperature and dust environments: the connection design of the actuator and the valve The irrational and multi-fulcrum lever linkage method can not only meet the requirements of the whole control system for the control precision and control stability, but also enlarge the output force of the angular stroke electric actuator. , So the control accuracy and control stability of the two valves are poor, can not meet the automatic requirements, since the production of the car has been in manual and. Site operating conditions, low control accuracy. ◆ large amount of routine maintenance, process operation difficulties: Since the control system on the equipment selection at the time there are certain flaws, there are always some problems in the actual operation, 2-3 times a week maintenance, And since the beginning of production technology has not been cast on automatic, increasing the operation of the process operator's difficulty. In order to solve the problems of the above equipment and better meet the requirements of process safety production, I decided to transform the pressure reducing valve and the temperature reducing water distribution valve on the temperature reducer and the control system thereof. According to the requirements of the process and the company Current production conditions, the two valves should meet the following process conditions: a) steam pressure reducing valve: Process Diameter: 150mm (DN150, PN1O) Medium: steam temperature: M ax 4 3 0 ℃ Flow: Q min 4T / h Q nor 15T / h Qmax20T / h Inlet pressure: 2.45MPa Outlet pressure: O. 35MPa With electric actuator: Power supply 220VAC / 50Hz Input signal: 4-20mA Valve position feedback signal: 4-2OmA Actuator with manual on / off handle or handwheel b) Water reducing valve: Process Diameter: 32mm (DN32, PN10) Medium: Water temperature: lO8 ℃ Flow: Qmax2500kg / h Inlet pressure: OMPa outlet pressure: 0.4MPa with electric actuator: 220VAC / 50Hz power supply Input signal: 4-2OmA Valve feedback signal: 4-2OmA Actuator with manual on / off handle or hand wheel According to the above process conditions , We will adjust the valve and the implementing agency separately from the model, first determine the implementing agencies, and then select the regulator valve, and then by the regulator to provide complete sets of suppliers. Second, the selection of electric actuator According to the needs of process operation and technical personnel requirements, the actuator of the control valve we have decided to use electric actuator, for which we grasp the information, we have chosen the following three in the world Within the more well-known electric actuator professional manufacturer. (1) Japan KOSO (2) Germany Auma (3) United Kingdom Rotork
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