In order to accelerate the pace of industrial upgrading of the power industry and achieve the goal of energy conservation and emission reduction in power plants. The power plant has completed the energy-saving transformation of the heat network decontamination device circulating water rubber ball pump from electric drive to steam drive, and the implementation of the transformation plan has effectively reduced the power consumption of the plant and played a good energy-saving effect.
In order to dig deep into the energy-saving potential of the power plant and reduce the power consumption of the plant, before the heating transformation of the steam turbine pump unit with steam source traction steam turbine pump system, the power plant has 2 sets of 50MW condensation unit with 3.02 million m2 of inter-steam supply network, 4200t of heat network circulating water, equipped with 4 electrically driven heat network circulation pumps, 2 transportation and 2 standby, flow rate of 1800m3 h, head of 97m, and supporting motor rated power of 710kw. The daily power consumption of 2 heat network circulating pumps is roughly calculated at 34080kwho in order to reduce the electricity consumption of 1 dian plant, the electric pump is transformed into a steam pump, and the steam turbine is used to drive the operation of the heat network circulation pump, and at the same time, the exhaust steam of the 2 steam turbines is used to heat the circulating water, and the steam heat energy is reused, and the energy is used in steps to increase energy saving. Technical parameters and requirements of circulating water rubber ball pump of heat network decontamination device:
Total flow of circulating water rubber ball pump of heat network decontamination device:
The total successor of the circulating water rubber ball pump of the heat network decontamination device should correspond to the design heat load, and the calculation should be calculated according to formula (2-1) g=3600q 41868 - In the cut formula, g denotes the total circulating water volume of a net, t h;q represents the design heat load, mw;l represents the temperature of the circulating water supply of the primary heating network, °C;The bow represents the return temperature of the circulating water of the primary heat network, °C;The design flow rate of a single heat network decontamination device circulating water rubber ball pump = 1,1 * the total flow rate of the circulating water rubber ball pump of the heat network decontamination device The number of circulating water pumps, see equation (2-2): g° = lq (2-2) where the formula n, g. It represents the design flow rate of circulating water rubber ball pump of a single heat network decontamination device, t h;n represents the number of circulating water rubber ball pumps of heat network decontamination device, units;Heat network decontamination device circulating water rubber ball pump head.
The head 2 of the circulating water rubber ball pump of the heat network decontamination device shall not be less than the sum of the pressure loss of the heat network heater (including the heat network heater of the secondary heat exchange station), the primary heat network and the secondary heat exchange station under the design flow conditions of the pump. It can be designed according to the difference between the water supply pressure and the return pressure of the primary heating network provided by the external network design unit.
Main technical requirements for circulating water rubber ball pump of heat network decontamination device:
1) The axis alignment error between the unit and the pump woo3mm；
2) The vibration amplitude of the steam turbine wq03mm (under the condition of the vibration amplitude of the water pump wq03mm);
3) The steam seal should be made of side teeth.
4) The oil baffle adopts the oil seal tooth rebound oil baffle;
5) Inlet valve type: quick closing, automatic main valve, adjusting valve for split type.
6) Steam turbine lubrication method: the front and rear bearings are self-lubricating sliding bearings, and the bearing material is babbitt. Thrust bearings are self-lubricating with rolling bearings.
7) Ambiguous machine requirements:
a.Open all the trap valves of the steam turbine and open the isolation valve of the main steam pipe to drain the warm pipe.
b.Rotate the main valve handwheel counterclockwise to make the main valve gradually open, and after the rotor is impulsive, the small main valve is closed to slowly increase the speed of the unit to 500 600r min, and the low-speed warm-up is carried out, the duration is about 15 20 minutes, during which the main engine can be gradually closed when it has been heated evenly.
c.After confirming that the unit is running normally, the speed will be increased at a rate of 300r min to the rated speed.
8) Protective device:
a.The steam turbine is equipped with a mature and reliable emergency security system (mechanical) to prevent overspeed, and the electric overspeed is a two-of-three mode, and there is a speed display instrument on the spot.
b.The steam turbine is equipped with an interlocking protection device to prevent the steam turbine from suddenly re-entering the steam (closing the main and adjusting valves). A manual emergency shutdown operating device is set up on site.
c.The main valve of the small machine is a switch door.
d.The unit should have a local and remote use of the gate device.
Energy-saving technical transformation scheme of circulating water rubber ball pump of heat network decontamination device:
The project uses 50MW unit four-stage heating and steam extraction to drive 2 steam turbines, and during the heating period, 2 steam pumps are discharged into 2 heat networks and 5 heaters to heat 2 heat network return water, increase the temperature of 2 heat network return water, and reduce the electricity consumption rate of 1 plant at the same time, so as to achieve the purpose of energy saving.
The specific implementation steps are as follows;The 2 heat network circulating pumps were dismantled, and 2 new steam turbine pump units were installed in the original location.
The design parameters of the heat network circulating pump are: rated flow rate 2000t h, rated head 90 100m, rated speed 3000r min, shaft power 700 770kkw;The high-speed heat network pump is dragged by a low-pressure inlet steam turbine, and the steam inlet pressure of the steam turbine is 02-0.25MPa, the exhaust pressure is 002MPa, and the inlet and exhaust steam flow of each steam turbine is about 24t h.
Install the heat network circulating pump steam turbine inlet and outlet steam pipelines and valves, connect from the 2 heat network heating extraction mother pipe to the heat network circulation pump steam turbine, and the exhaust steam pipeline is connected to the 2 heat network 5 heater steam inlet mother pipe. Add 2 hydrophobic coolers (the hydrophobic heat of the heat network shares 1 hydrophobic cooler, and the heat exchange is 16279kw plate heat exchanger, one transport and one standby, heating 2 heat network return water), and the hydrophobic water of the heat network heater is cooled by the hydrophobic cooler and discharged into the deaerator. During the heating period, two steam circulation pumps are operated in 2 heat networks, and two electric circulation pumps are in standby. Economic Analysis of Circulating Water Rubber Ball Pump of Heat Network Decontamination Machine:
Take the power generation of 213 days (5592h) of the heating period in 2013 as an example: 3 machines 172500000kwh, average load 308476kw, 4 machines 163272000kwh, average load 2919742kw, a total of 335,772,000kwh, an average of 60,045kwo 2 heat network circulating pumps to save electricity, the current before the change is 46 puppet single pump power = 105x46x1.732x0.813=680kw；Double pump power = 680x2 = 1360kw, 2 pumps consume plant electricity consumption in one day = 1360x24 = 32640kwh;A heating period consumes the electricity consumption of the plant = 1360x24x233 = 7605120kwho
1) After the transformation, the heating period adopts the mode of steam pump running electric pump backup, which can save 32.64 million kWh, saving 760 yuan of electricity consumption in one heating period5.12 million kWh.
2) After the transformation, the annual electricity consumption of the plant will be saved by 760512 million kWh, according to the power generation cost of 023 yuan kWh calculation, saving the power consumption of the plant every year to achieve economic benefits of 174920,000 yuan.
The transformation of the circulating water rubber ball pump of the heat network decontamination device not only saves the power consumption of the plant, but also increases the heating area and realizes the optimization of the operation mode of the power plant. After the popularization and application of this technology, it can reduce the production and operation cost of 1 Di thermal power plant to a large extent, and has good economic benefits and promotion prospects.