NELES control valve in the transformation of the application of temperature and decompression First, the process conditions and process conditions before the transformation In my company for the production of steam in the process, there is a key device for the temperature reducer, the device will produce steam boiler (Without power generation by the steam turbine) from 2.480 MPa430 ° C, reducing the pressure to 0.35Mpa and 170 ° C to meet the demand of the company's other steam units. The reduction on the reducer Pressure valve and water distribution valve for the reduction of the temperature and pressure reducer plant support, 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 able to meet The Company's Production Requirements: However, during the four-year operation period, we also found some problems with the equipment. The main focus of the day: • 100,000 tons of steel products will be exported to Taiwan by the end of the month. • Shaanxi limits over-wood packaging • Powder coating market formed four major needs • Stainless steel equipment to update the NC products into the new pet in the following aspects: ◆ The pressure relief valve leakage, especially in the steam through the steam turbine Under the condition of electricity, the pressure reducing valve should be completely shut down under such conditions. However, due to the structure and product quality of the double-seat valve itself, the valve still has large steam leakage in the fully-closed position Amount, resulting in unnecessary energy loss, increased 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 We know the basic situation of the three factories as follows: Manufacturers KOSO Auma Rotork Products Origin China Anshan Germany UK Production Scope Chemical, power plant chemical, power plant chemical, power plant drive Method Belt Drive Gear Drive Gear Drive Manual Operation Without Handwheel Handwheel With Handwheel Output Torque 0N · M-1500 N · M 30 N · M-32000 N · M 30 N · M-30000 N · M Applicable Ambient Temperature Range -10 ℃ - +60 ℃ -25 ℃ -80 ℃ 0 ℃ - + 120 ℃ -25 ℃ -80 ℃ Overload protection No overload protection Overload protection Overload protection From the above three products, we have chosen the German Auma Electric actuator: 1> Ambient temperature: At present, our company is using the temperature reducer near the ambient temperature, we measured as: 10cm away from the seat at a temperature of about 220 ℃, up and then up this point 15cm, Here the temperature is 7 2 ℃, and the current factory application of more than 3000 sets, specifically similar to our office The temperature at the electric actuator used is 56 ° C. According to our experience of using KOSO in recent years, KOSO is less than 6 ℃ to ambient temperature, but the electric mechanism appears abnormal when it is around 57 ℃. As a result, KOSO's electric actuator can not be used on this reducer, while Auma and Rotork have a working range of -25 ° C to 80 ° C and Auma has a high temperature version that expands the applicable ambient temperature range to O ° C. 120 ℃, and in our application here, the choice. 25 ℃ ~ 8O ℃ ordinary type can be. 2> output force cabinet: At present, the rated output power cabinet of servo motor on the 20T / h pressure reducing valve of our company is 25ON · M, but a lever should be provided when releasing the pressure reducing valve, which enlarges the force by 6 times Lever arm respectively 65cm than 11cm). So this valve output torque actually 15OON · M or so, and can be seen from the table, l500N · M torque output KOSO electric actuator is the upper limit, there is no margin, so only Auma and Rotork are ok. 3> Application: ◆ KOSO electric actuator has many applications in our power plant, which is used well under the conditions of low ambient temperature (below 53 ℃) and small torque output (below 5OON.M) Less maintenance, the operation of these years are also more satisfied. ◆ Auma electric actuator My company's maintenance staff have experience in the use and maintenance of the product, according to maintenance staff to reflect that this implementing agency spent more than 10 years, have been able to have a good job, very little maintenance, Construction We use this actuator. ◆ Rotork electric actuator is used in our brother unit. The power station of this plant has several Rotork electric actuators which are also used for the control valve. It has been working for more than one year and has been working very well with almost no maintenance volume. ◆ In terms of performance and price, Auma prices are in the balance between our understanding and comparison. Third, the selection of the control valve Selection of the control valve, involving more factors, consider the factors are also very complex, involving a number of professionals, not the professional manufacturers in this area, some factors may not be afraid of fear, but this device For us it is both critical and costly, so when choosing a supplier, we have the following principles: • The manufacturer must have a complete after sales service and timely technical support. • Must be a big manufacturer famous in the world and having good production and service performance in this area, mainly considering product quality and reputation. • The price must be competitive. Based on the above three reasons, we have selected three manufacturers based on the information and situations we have: Fisher, the United States, Neles, Finland and Samson, Germany. After receiving the above process conditions, the representatives of the above three companies have repeatedly contacted and repeatedly verified the relevant technical and process parameters and made the selection. Both of them have provided the calculation and selection of control valves (According to our request, with Auma electric head and commissioning, assembly delivery), the situation is as follows (right) Table: Tianjin Fisher Germany Samson Shanghai Office Finland Neles Shanghai Office Selected Model ED-F "& ED-1 "TYPE251 & TYPE241 QXA-T5D13061DE4.3 & FCO1DWSXKLGTDH3 Delivery Lead Time 12-16Weeks 12-14Weeks 16-20Weeks (Including 4 Weeks Sea Freight)