310 m³/min Turbine Fan System Used in Paper Making Industry
Description
The suction capacity of turbine is large. Generally, multiple
points with similar vacuum requirements can be used together. When
it is used as a vacuum equipment, it has the characteristics of
centralized equipment, high efficiency and low energy
consumption.Taking a 400 Thousand tons paper machine as an example,
only three turbines are needed, the total installed power is
6550kw, and its vacuum capacity is equivalent to the requirement of
15 sets of water ring vacuum pumps with installed power of 8810kw,
but the installed capacity is reduced by 2260kw. Under the same
circumstances, it can save about 25% energy than the ordinary water
ring vacuum pumps; after the air is rapidly heated and compressed
by the turbine, the temperature of the discharged air is as high as
120-180 ℃, and the remaining heat is usually used for heating the
white water and air system of the paper machine through the heat
exchanger.The turbine does not need water as the medium when it
works, and the annual consumption of water for the water ring
vacuum pump is about 300000 tons per year. A single-stage turbine
is designed with 24 deflectors on the shell outside the impeller,
which can adjust the flow rate of air through the turbine, so as to
adjust the vacuum degree.
Introduction
Turbine fan is a kind of special centrifugal fan, which is
generally divided into multi-stage closed centrifugal fan and
single-stage open centrifugal fan. They use the multi-stage
impeller installed in the shell and diffusion system to form
vacuum. With the rotation of the impeller, air enters the hole in
the middle of the impeller, and is accelerated and pressurized in
the process of radial outward movement. Then the second stage
impeller accelerates the air from the first stage, and then to the
third stage and the fourth stage, so as to generate vacuum. The air
is inhaled from different levels, thus producing different vacuum
degrees to meet the needs of the paper machine vacuum system. As
shown in Figure 1 is a simple schematic diagram of a multistage
turbine.
No matter multi-stage closed fan or single-stage open fan is used
as vacuum pump, it has the characteristics of large suction and
stable vacuum level. However, when the vacuum is high and the
amount of air available for suction is less and less, air reflux
and surge often occur. At this time, the heated air after being
accelerated flows back to the suction port, and the intake pipe
will be heated, which will seriously damage the stability of the
vacuum degree. Therefore, the inlet of each turbine is equipped
with anti surge valve. When the vacuum degree is high and the
suction capacity is insufficient, the anti surge valve will
automatically open according to the effective power of the turbine,
and increase the air flow to prevent the occurrence of surge, so as
to make the equipment power consumption and the required vacuum
degree stable.
Process Flow Diagram of Using the Turbine
Generally, a multistage turbine and two single-stage turbines are
used in parallel. Each part of the paper machine that needs the
same vacuum degree is connected to one or more concrete gas-water
separation tanks. Figure 2 is the basic process flow diagram of
using the turbine.
Use notice
When the turbine is used in the vacuum system, its operating speed
is higher. The operating speed of the multi-stage machine is
generally 5000r / min, and that of the single-stage machine is more
than 10000r / min. Therefore, the whole equipment needs a heavy
foundation with high quality to prevent high frequency vibration.
Due to the large power of a single device, the load fluctuation of
the system grid will be caused when the device is started or
stopped. Before each start, the motor protection program will check
whether the shutdown time is enough for a specified time interval.
The impeller speed of the turbine is very high, so the machining
and installation accuracy of the equipment is required to be
improved accordingly, and the high-precision dynamic balance test
of the impeller is required at high speed. In order to prevent
moisture or foreign matters from entering, a large-scale concrete
air-water separation tank must be set up. Stainless steel plate is
used for partition inside the separation tank, the maximum wind
speed shall not exceed 3m / s.
After the machine is installed, it is necessary to thoroughly clean
the pipeline to prevent foreign matters from remaining in the
pipeline and damaging the equipment.
Common faults and their causes
- The causes of equipment vibration include: motor vibration; loose
bearing or bearing seat; impeller damage or coupling misalignment;
gearbox damage.
- The reasons for the high bearing temperature are mainly: improper
use of lubricating oil; low quality of lubricating oil; failure of
detection system.
- When the liquid level of the oil tank is low in the preparation
state, please check whether there is leakage in the oil tank.
- When the liquid level of oil tank is low in operation state, please
check whether the cooler is broken down and the oil enters the
cooling water.
- When the level of lubricating oil tank becomes high, it is maybe
because the cooling water has entered the oil system.
- High temperature of lubricating oil may be caused by insufficient
cooling water flow, too high temperature of cooling water itself,
or failure of detection system.
- If there is surge in the turbine, it may be caused by too low air
flow, closed valve on the pipeline, or loading capacity error of
the machine.
The advantages of centrifugal vacuum pump compared with water ring
pump
| Item | Water ring pump | Centrifugal vacuum pump |
| Cost Performance | Its low efficiency and high power consumption makes its comprehensive use cost high in spite of its low manufacturing cost | Its high efficiency makes its comprehensive use cost low even the manufacturing cost is high |
| Technology Advancing Level | Low | High |
| Average Service Life | 3-5 years | 10-20 years |
| Efficiency | Polytropic efficiency | Adiabatic efficiency 80%~90% |
| Quality | Poor operational reliability | Great operational reliability, aviation-grade material |
| Final Vacuum | -98kPa | For Single stage: -65kPa For Double stage:-85kPa |
| Applicable Situation | Low flow rate, high vacuum degree(above -70kPa) | High flow rate,stable vacuum degree(-30 ~ -75kPa) |
| Conversion of power and flow | 100kW=60~86m3/min | 100kW=110~120m3/min |
Parameters of High-Speed VF Centrifugal Vacuum Pump
MODEL | Motor Power KW | Shaft Power KW | Air Flow m3/min | Vacuum Degree Kpa |
GDV110 | 110 | 95.3 | 120 | -50 |
GDV160 | 160 | 139.1 | 175 | -50 |
GDV200 | 200 | 174.7 | 220 | -50 |
GDV250 | 250 | 217.4 | 275 | -50 |
GDV280 | 280 | 246.1 | 310 | -50 |
GDV315 | 315 | 273.9 | 345 | -50 |
GDV355 | 355 | 309.6 | 390 | -50 |
GDV400 | 400 | 349.3 | 440 | -50 |
GDV450 | 450 | 396.9 | 500 | -50 |
GDV500 | 500 | 436.7 | 550 | -50 |
GDV560 | 560 | 484.3 | 610 | -50 |
Remarks 1.Above Design Parameters are obtained based on below conditions: Suction Medium: Air, Relative Humidity: 65%, Suction Air
Temperature: 35℃, Discharge Pressure: 101.3kPaA 2.For special working conditions or vacuum condition changes, the
vacuum pump can be designed according to actual demands. Please refer to pre-sale service. |
