Advantages of TRT
1. energy recovery: the original blast furnace gas is washed and dedusted, and then passes through the pressure reducing valve group to reduce the pressure of about 170KPa to a suitable level and send it to users. This process consumes the residual pressure of blast furnace gas in vain. Through TRT unit, the residual pressure of gas can be converted into electric energy, and then it can be transmitted to the end users, and the original useless residual pressure can be converted into electric energy, which can obtain certain economic benefits. 2. Better control the top pressure. Generally speaking, it is better to adjust the top pressure of blast furnace through the static blades of TRT unit than the pressure reducing valve group, which can bring more stable top pressure of blast furnace. The stable top pressure can make the blast furnace easier to control and has a positive effect on the output (for example, the "3H technology" of Shaanxi Drum). 3. Reduce noise, because the pressure reducing valve group is completely closed, the gas passes through the turbine, and the noise and vibration are converted into electric energy in the form of work, so the noise of the pressure reducing valve group can be effectively reduced. The gas produced by TRT blast furnace enters TRT device through gravity dust collector and two-stage venturi tube. Through imported electric disc valve, imported cartridge valve, speed regulating valve and quick-cut valve, the turbine expands to do work and drives the generator to generate electricity. The gas from the steam turbine enters the low-pressure pipe network and is connected in parallel with the pressure reducing valve group in the gas system. The generator outlet circuit breaker is connected to the 10KV system bus and connected to the power grid through the local substation. When TRT is running, the generator delivers electricity to the power grid. When the blast furnace is short-term, the generator is not listed as electric operation. TRT device consists of steam turbine main engine, large valve system, lubricating oil system, hydraulic servo system, water supply and drainage system, nitrogen sealing system, high and low voltage power generation and distribution system and automatic control system. 1, characteristics of blast furnace gas turbine; The gas volume and pressure of the main engine of blast furnace gas turbine are not high, but the flow rate is quite large. Although it has been dusted many times, it still contains a lot of ash particles and is saturated with water vapor. Based on this, the turbine design can not be completely designed by gas turbine method, but by new design methods such as large flow area, bottom speed and straight and thick blade profile. Structure: It consists of stator, rotor, adjustable stator blades, bearing, base, etc. Function of components: Bearing: support bearing, four-blade sliding bearing, oil supply lubrication, thrust bearing, kingsbury-type forced oil supply lubrication adjustment: two-stage all-stator adjustable servo adjustment seal: inflatable nitrogen seal is automatically and continuously adjusted according to top pressure fluctuation, and cleaning: low-pressure spray water is intermittently or continuously sprayed. Stator: The rotor is composed of the turning gear of the fixed vane adjustable diffuser, etc. The rotor is composed of two-stage moving blades of the main shaft. Turning direction of emergency protector: viewed from the entrance direction, the rotor rotates clockwise; When the electric turning gear exceeds 6r/min, the overspeed protection will be automatically lifted; When the speed exceeds 10%, the electrical system: quickly open the quick-opening valve of the pressure regulating valve group, and close the quick-closing valve, speed regulating valve and stationary blades at the same time. Mechanical system: the throttle valve of the emergency protector acts to close the quick cut-off valve. 2. Large valve system 2. 1 Flow chart of inlet electric secondary eccentric valve D947H-3, nominal diameter DN 1800mm, nominal pressure PN0.3MPa, medium temperature ≤250℃, suitable for medium blast furnace gas.
Structure principle structure: mainly composed of valves, motors, primary electrical devices, secondary transmission devices and controllers. Principle: When the valve is running, the controller or inching button starts the generator, which drives the primary and secondary transmission devices and drives the valve stem to rotate, so that the butterfly valve rotates within the range of 0 ~ 90℃, thus completing the opening and closing of the valve or stopping at a certain angle, and achieving the purpose of isolating the medium in the pipeline or adjusting the cut-off flow. Because the valve body adopts elastic seat and eccentric sealing structure, the valve becomes more and more compact in the closed state, which ensures that the valve seat is a little worn, but the sealing condition is reliable. 2.2 imported hydraulic gate valve YZG749AX-2C nominal diameter: DN 1800mm nominal pressure PN 0.2 MPa (g) applicable medium blast furnace gas medium temperature 250℃ driving mode full hydraulic structure principle: the valve consists of a main valve body and a left-right valve body, and the valve plate and valve plate actuator (including valve plate clamping and releasing mechanism and valve plate operating mechanism) are arranged in the main valve body. The top of the main valve body is provided with a discharge pipe and a sampling pipe, and the bottom is provided with an N2 pipe, a drainage pipe and a dust cleaning hole. The left and right valve bodies are fixed in the set position with bolts. The hydraulic transmission system consists of a ball plug motor, a spring reset cylinder, a clutch cylinder, a gear oil pump, a control adjusting device, a one-way valve, a sequence valve and an overflow valve. Three-position four-way valve, oil tank, cooler, oil filter, electric heater, pressure gauge, etc. Export electric secondary eccentric valve YZG749AX—0.3 Nominal diameter DN2400mm Nominal pressure PN0.03MPa Suitable medium blast furnace gas driving mode: The structure and principle of full hydraulic valve are the same as those of imported cartridge valve oil station, and the valve hydraulic control device is self-contained and operates independently. 2.5 quick shut-off valve KD 743-2 Nominal channel DN(mm) 1800 Nominal pressure PN(bar)2 Leakage: (Nm/h)5000 Resistance loss: quick closing time: applicable temperature: applicable medium: dusty flue gas, air and gas. Structure and principle structure: Quick cut-off valve is mainly composed of valve, transmission device, hydraulic control box and electric control box. The valve adopts double eccentric disc valve type, and the valve seat is stainless steel surfacing. Corrosion resistance and wear resistance, prolonging the service life of the sealing pair. The hydraulic control box is connected with the transmission device through a high-pressure hose, and controls the oil to make the piston of the oil cylinder move to open and close the valve. The hydraulic components are installed in the hydraulic control box. The electric control part is equipped with local manual operation and remote control in the control room, which realizes the functions of slow opening, slow closing, fast closing and independent swimming in two places. Principle: adopt spring hydraulic balance type, double eccentric disc valve, hydraulic oil in working state presses the spring, and the valve opens. When the TRT device is abnormal (the action signal comes from the system control signal all the way and the hydraulic signal from the turbine emergency protector all the way), the solenoid valve acts, the quick oil drain spring is loosened, and the valve is closed urgently. The cut-off time can be adjusted in the range of 0.5 to 1 sec. 3. Function of lubricating oil system 3. 1 System Large steam turbines and compressors are supported by bearings. An important link to ensure the safe and reliable operation of the unit is to provide a certain amount of dilute oil circulation lubrication to each bearing lubrication point in time to meet the lubricating oil supply under normal and accident conditions of the unit. This system is the lubricating oil system. 3.2 The system consists of lubricating oil station, high oil tank, oil pump, valve and side inspection instrument. The lubricating oil station sends the lubricating oil with a certain pressure and flow rate to all lubricating oil points of the bearing for lubrication after being cooled by the oil tank cooler and filtered by the oil filter. High-level fuel tank is a lubricating oil supply that uses natural potential difference to maintain the idle oil flow time of mechanized grouping during power failure, emergency and shutdown. Detection instruments are divided into local instruments and remote transmission instruments. A control panel is set on the ground to display the pressure and temperature values of each measuring point. Remote transmission meter: transmitters are installed at important measuring points, and the measured signal values are sent to the main control room for recording, display and alarm interlocking, so as to meet the control needs of the steam turbine unit during normal operation. 3.3 Control principle of the system When the unit is in normal operation, the operator can master the operation of the oil system only by observing the temperature and pressure display values of each measuring point on the control panel. When there is a small fault in the spool of the oil pump or the pressure difference of the dirty oil filter exceeds the limit, the supply pressure of lubricating oil will gradually decrease. When the pressure at the farthest point drops to 78.4KPa, the light plate on the dial of the main control room will light up and the buzzer will sound. Whether the operator has observed it or not, it has been reminded to start inspection and processing, and another oil pump is automatically put into oil supply at the same time. When the short-term fault is eliminated, the auxiliary pump can be stopped automatically or manually. If the short-term fault cannot be eliminated, the system will switch to the heavy fault handling mode. When the alarm and auxiliary pump were put into operation, the operators could not eliminate the equipment problems in time, but the oil pressure continued to drop. When the pressure reaches 49KPa, it will give an alarm and stop automatically to ensure the safety of the unit and avoid serious failure. When the equipment is out of power or the oil pump fails to supply oil, the oil supply of the unit is maintained by the natural potential difference of the high oil tank when the unit stops, that is, the oil flow lubrication required by the rotating inertia. 4. The role of electro-hydraulic servo control system 4. 1 system The electro-hydraulic servo control system belongs to one of the eight subsystems in TRT device. According to the instructions of the main control room, TRT is controlled systematically, such as starting, stopping, speed control, power control, top pressure and process detection. To realize the function control of the above system, it will be embodied in controlling the rotating speed of the steam turbine and the opening of the stator blade. The means to control the opening of the stator blade is the electro-hydraulic position servo system. The precision and error of the control system directly affect the control of each stage of the TRT system. It can be seen that the position and function of the system in TRT is very important. 4.2 The system consists of hydraulic control unit, servo cylinder and power oil station. The hydraulic control unit includes a speed regulating valve control unit and a permeable blade control unit, and each unit consists of an electro-hydraulic servo valve, an electric solenoid valve, a quick closing solenoid valve, an oil circuit block and a base. Servo cylinder adopts double piston rod structure, which has small friction and good sealing performance. The power station consists of oil tank, variable displacement oil pump, oil filter, cooler, pipeline valve and testing instrument. 4.3 System Principle After scheme design, it is determined that the electro-hydraulic servo control system consists of three parts: machine, electricity and liquid. The control block is shown in the figure. The command signal sent by the servo controller of the valve plate position sensor of the oil source hydraulic lock servo valve cylinder crank mechanism in the automatic control system is compared with the actual position signal of the oil cylinder in the servo controller and becomes an error signal. It is sent to the electro-hydraulic servo valve, which converts the electric signal into hydraulic oil flow according to a certain proportion to push the oil cylinder to move. The feedback signal sent by the position sensor changes continuously until it is equal to the command signal, and the oil cylinder stops moving, that is, stops at the designated position, so that the louver is stable at this opening. The linear motion of the oil cylinder is converted into the rotary motion of the valve plate through a set of cranks, which changes the working angle of the valve plate or the stator blade. From the above analysis, it can be seen that with the constant change of system signal, the opening of permeable stator blades will also change, and the purpose of controlling the number of revolutions, gas flow and turbine output can be achieved by changing the opening of stator blades. 5. Water supply and drainage system The water supply and drainage system consists of sealed drainage tanks, drains, valves and water coolers of each oil station. (Dry TRT also needs to keep wet water supply and drainage system equipment) The sealed drainage tank and drainer are welded by unified steel plate, and other oil-water coolers are purchased separately. System principle In order to prevent the turbine from being blocked by dust, soft water spraying facilities are set up. The water spraying point is in front of the governing valve body and the first stage stator blade of the turbine main engine. According to the dust content of the gas at the inlet of the turbine and the dust accumulated in the turbine, continuous water spraying or intermittent water spraying can be selected. Periodic flushing nozzles are arranged in front of the valve bodies of the emergency quick closing valve and the speed regulating valve. In order to safely discharge the mechanical water and condensate in the front and rear pipelines of the turbine main engine and the main engine, a drainage sealing box and a three-stage drainer (effective water seal of 4800mmH2O) are set up. The drainage at different pressure points flows into the drainage sealing box through the drainage pipe and orifice plate (the gas leaked with the drainage returns to the turbine outlet pipe through the gas phase pipe at the top of the sealing box). Then the sewage is discharged through a three-stage drainer. The bottom of the drainage sealed tank is equipped with regular flushing nozzles, which can be stirred to prevent dust accumulation, and can also replenish water through these nozzles. Water supply: turbine spray water-industrial fresh water quick closing valve, speed regulating valve, oil cooler-blast furnace net circulating water 6. Nitrogen sealing system steam turbine works, and the working medium is blast furnace gas, which belongs to flammable and toxic gas and must not be leaked. Its sealing medium is nitrogen. The nitrogen pressure of the steam turbine shaft end seal (low-pressure seal branch) composed of two branches is generally 0.3~0.4MPa, and then the nitrogen pressure at the seal is about 0.02~0.03MPa higher than the seal gas pressure after being adjusted by the pneumatic membrane regulating valve to ensure that the gas does not leak. Nitrogen consumption should be lower. There is no standby gas source, and in principle, it will stop when there is no nitrogen. The high-pressure sealing branch provides nitrogen for the shaft seal of the emergency quick-closing valve and the shaft seal of the speed regulating valve. 7. High and low voltage power generation and distribution system The residual pressure turbine generator of blast furnace gas is a recovery device that uses the pressure energy of blast furnace gas to drive the generator through turbine expansion, and is an accessory equipment of the blast furnace system. The characteristics of residual pressure power generation determine that the output of generator can not be adjusted according to the needs of load, but only according to the changes of blast furnace working conditions. Under the premise of ensuring the stability of blast furnace top pressure, as much power as possible, U output changes with the fluctuation of blast furnace top pressure. 7. 1 Composition of system synchronous generator: The generator is a brushless excitation stepping generator of Beijing Heavy Power Plant. Because there is a lot of dust on site, the generator adopts a closed self-circulation scheme of wind and water cooling and ventilation. The generator adopts permanent excitation mode, which can meet the requirements of automatic and manual excitation adjustment, demagnetization and magnetizing for 5 minutes to unload the load, and can transition from generator operation state to electric operation state, and also meet the requirements of restoring from synchronous motor state to generator state in operation. The magnetizing device also has the ability of automatic adaptation, and the reactive power output by the generator under the running state of the motor can be adjusted according to the needs of the power grid. 7.2 High and low voltage distribution system: it consists of four handcart high voltage cabinets. There are manual quasi-synchronous grid connection and automatic quasi-synchronous grid connection. Protection functions include: longitudinal differential protection, over-current protection, under-voltage protection, loss of excitation, low frequency, reverse power and other protection functions. 7.3 Electrical control of hydraulic oil station of low-voltage electronic control system: two oil pumps are mutually standby. When the system pressure is lower than11MPa (110 kgf/cm2), the standby oil pump will be put into operation automatically and stopped manually after troubleshooting. When the oil temperature is lower than 20℃, the oil pump cannot start by itself. It must be heated at this time. When the temperature rises to 25℃, the heater will automatically turn off and then start the oil pump. Electrical control of lubricating oil station: heater control. Manual heating, when the temperature reaches 25℃, it will be automatically disconnected and the heater will stop working. The two oil pumps are mutually standby: when the oil pressure in the lubricating oil pipe is lower than 0 or so. 08 MPa (0 .8KGF/CM2), the auxiliary oil pump is automatically turned on, and the system oil pressure is higher than about 0. 2 MPa (2 kgf /CM2), stop manually. The opening and closing operation of valve interlocking water spraying electric ball valve can be operated in the control room and on site. The operation mode can be continuous water spraying or intermittent water spraying. Through the time relay, the time delay is set, and the water spraying electric ball valve is switched on and off regularly to realize intermittent water spraying. When the water level of the sealed water tank exceeds the limit, the valve is closed by interlocking action. The electric ball valve for flushing water can be opened and closed in the control room and field operation box. At the same time, when the water level of the sealed tank exceeds the limit, the valve is closed by interlocking action. Drainage electric ball valve, the opening and closing can be controlled and carried out in the field operation box. At the same time, the opening and closing of the emergency quick-closing valve are interlocked. When the emergency quick closing valve is completely closed, the drain valve will automatically open completely after a set delay of about 120 seconds. When the emergency quick cut-off valve is fully opened, the automatic system contact is closed and the drain valve is automatically closed. The opening and closing of the pressure relief bypass can be manually operated in the control room and on site, and interlocked with the inlet hydraulic gate valve. When the hydraulic insertion valve is fully opened, the pressure relief bypass valve is closed. When the hydraulic insertion valve is completely closed, the pressure relief bypass valve will automatically open. The electric turning machine can be manually operated on site to start the turning motor. When starting, hang the turning gear. When the speed exceeds 6R/MIN, the travel switch will automatically stop the motor. 8. Automatic control system The instruments of this system mainly adopt UXL small and medium-sized distributed control system of Yokogawa Corporation of Japan and TDC3000 distributed control system of HONEY WELLG Corporation of the United States. The measurement and control instrument of steam turbine shaft motion adopts Bentley's 3300 instrument. Electro-hydraulic servo controller, a selected product developed by Aerospace Department 609. The system consists of feedback control system, speed regulation system, power regulation system, blast furnace top pressure compound regulation system, override control system, electro-hydraulic position servo control system, nitrogen seal pressure difference regulation system and sequential logic control system. The above system is used for the start-up operation and process detection control of TRT devices. On the premise of ensuring the normal production of blast furnace and the fluctuation of top pressure not exceeding the limit, the operation and control of TRT device such as start-up, speed increase, grid connection, power increase, top pressure adjustment, normal shutdown, emergency shutdown, electric operation and normal operation are successfully completed. TRT working principle TRT is an energy-saving device that uses the pressure energy and heat energy of blast furnace gas to do work through turbine expansion and drive the generator to generate electricity, thus recovering energy. The relationship between TRT and pressure relief valve group is an important means of pressure control at the top of blast furnace. According to the different capacity of the furnace, the caliber and number of valves in the pressure relief valve group are different, but their functions are the same. The pressure reducing valve group is generally composed of an automatic valve, two or three manual valves, etc. TRT device and blast furnace pressure reducing valve group are both in series and parallel in gas pipe network configuration. TRT is connected in series behind the pressure reducing valve group. During normal operation, the pressure reducing valve group is fully opened. Advantages: it is suitable for pressure reducing valve group with large leakage and difficult transformation. Disadvantages: The security of the whole system is worse than that of parallel connection. TRT is connected in parallel with the pressure reducing valve group, which is completely closed during normal operation. In order to cooperate with the TRT project, the parallel operation of the pressure reducing valve group was reformed: an automatic valve was set to receive the control signal of the top pressure regulator and automatically adjust the top pressure. A range valve is set, which is automatically adjusted according to the valve position of the automatic valve to ensure that the automatic valve works in the linear region. Set two quick-opening valves, one for use and one for standby. When TRT breaks down and stops in an emergency, the valve can open automatically to ensure that the fluctuation range of top pressure is within the allowable range. Pressure reducing valve group is generally used for ironmaking, and TRT is generally placed in power plant. In order to simplify the relationship between the two auxiliary units, the pressure reducing valve group can be left unchanged, and the steam turbine can be bypassed in parallel to open the valve quickly. This method is adopted in TRT device of our factory. TRT controls the top pressure of blast furnace. Pressure reducing valve group is an important means to control the top pressure of blast furnace. According to the size of the blast furnace, the caliber and number of valves in the pressure reducing valve group are different, but their functions are the same. The TRT device and the blast furnace pressure reducing valve group of 5# blast furnace belong to parallel configuration, and the pressure reducing valve group is fully closed during normal operation. Control of blast furnace top pressure The top pressure control system of blast furnace is mainly composed of top pressure control system and feedforward control. Principle of top pressure adjustment during normal operation of TRT: TRT adjusts the top pressure of blast furnace with the set value of top pressure of blast furnace at TRT side as the target value, and adopts PID adjustment to control the opening of TRT static blades, thus controlling the stability of top pressure of blast furnace. The stator blade is about 3kPa lower than the target value of blast furnace pressure reducing valve group to ensure the priority of stator blade adjustment. When TRT is running, the static blades are in automatic state, and the automatic valves of the blast furnace pressure reducing valve group are also kept in automatic state, and all valves of the pressure reducing valve group are closed. During normal operation, the quick-opening valves on both sides of the unit are all closed. One is in the automatic position (the adjustment target value is 3kPa higher than that of the stator to ensure the priority of stator adjustment), and the other is in the manual position. Once there is a problem with the adjustment of the stationary blades and the fluctuation of the top pressure exceeds the normal range, the bypass quick-opening valve in the automatic position will automatically participate in the adjustment of the top pressure. Feedforward control of blast furnace top pressure: measure blast furnace gas flow through TRT, and compensate temperature and pressure, so as to control the opening of bypass quick-opening valve. When the unit is in normal operation, the bypass quick-opening valve is fully closed; When a major fault occurs in the unit, the quick-opening valves on both sides of the unit can be quickly opened at the corresponding opening (the quick-opening valves on both sides of the unit can be quickly opened in both manual and automatic positions), and can be quickly opened before the quick closing of the stationary blades and quick-opening valves affects the blast furnace, so that the blast furnace gas can be unblocked and this unsafe factor can be eliminated. Top pressure control after major fault tripping: When a major fault occurs in TRT unit, quick-opening valves on both sides will control the top pressure. The quick-opening valves on both sides open the same opening at the same time, and the two valves automatically adjust the top pressure synchronously. After the blast furnace receives the TRT trip signal, the TRT operator can change the bypass quick-opening valve to manual operation, gradually close the bypass quick-opening valve, and hand over all top pressure control to the blast furnace control room.
TRT is classified according to dust removal process.
According to the different dust removal processes, there are wet dust removal and dry dust removal, and TRT is also divided into wet TRT and dry TRT.