Ⅰ. General
Recently, with people’s constant attention to environmental protection industry, low carbon environment has been an unavoidable problem for modern company to achieve sustainable development. In 2.28,2008, the Prevention and Cure Law on Water Pollution of the P.C.C has been revised by People's Republic of China of the 10th National People's Congress standing committee 32 meeting. This means that related national environment department will try to administer and supervise enterprise sewage discharge. As a result, being an unnecessary equipment of sewage treatment of power sector, the prospect of decanter centrifuge is bright and promising.
Ⅱ. Technical description of decanter centrifuge
Decanter centrifuge adopt the principle of centrifugal sedimentation to separate suspension. All kinds of suspension like equivalent diameter ≥3μm, weight concentration ratio≤10%, volume concentration ratio≤70%, or liquid solid density difference ≥0.05g/cm3 are all compatible to this decanter centrifuge. When applied to sectors, like petroleum, chemical, food, pharmaceutical, environmental protection, which needs solid-liquid separation, this decanter centrifuge makes it easier to achieve solid phase dehydration, liquid clarification, three-phase separation and size grading.
2.1 Main structure of decanter centrifuge.
LW450X1800-N decanter centrifuge
1. Transmission part of auxiliary machinery 2. Differential 3. Electric cabinet
4. Collecting box 5. Liquid inflow 6. Electrical apparatus control system
7. Transmission part of main engine 8. Bedplate 9.toolbox
2.2 Diagram of main engine
Main engine of LW450X1800-N decanter centrifuge
1. Bearing block 2. Big end bearing 3.Linker 4. Seal carrier 5. Big end plate
6. Liquid flow plate 7.oil seal 8. Propeller big-end bearing 9. Splined hub 10 .Straight drum
11. Propeller 12. conical rotary vessel 13. Propeller small-end bearing 14. Oil seal
15. Small side dish 16. small end bearing 17. driven wheel 18. center tube
Ⅲ . Application of decanter centrifuge to power sector
3.1 Application in thermal power plant: Flue gas desulphurization in thermal power plant
Desulfurization principle:
2CaCO3+4H2O+2SO2=2CaSO4.2H2O+2CO2
Process description:
The flue gas from boiler induced draft fan is supercharged by booster fan, then flow into flue gas heat exchanger, when it is cooled, the flue gas will flow into absorption tower. Next, they will get to the limestone slurry droplets which are sprayed by the tower spray. The SO2 in flue gas and CaCO3 in seriflux will generate CaSO4 and gypsum. When the flue gas is demisted and discharged from absorption tower, it will heat up by gas-gas heater. And when the produced gypsum liquid is dehydrated by decanter centrifuge, desulphurization by-product gypsum will be made. This technology can ensure the desulfurization degree up to 95% or more.
Outline process chart:
3.2 Condense dehydration of industrial sewage in thermal power plant
The industrial sewage of thermal power plant is mainly circulating cooling wastewater and industrial cooling water. On the one hand, when the circulating water from power plant get to air, it is easy for airborne particle get into circulating cooling water. About 4/5 precipitate leave in the cooling tower, which makes precipitate of circulating cooling wastewater increased. On the other hand, when circulating water is evaporated, solid content in water must be increased. The precipitation is also produced by salt composition when put phosphate into the water. In conclusion, sewage water of circulating cooling water are mainly suspended matter and solid content produced in water.
Industrial sewage are mainly suspended matter and COD, so if these matter are controlled, it is easy for them to be used as circulating water. Decanter centrifuge can be used to concentrate waste water and dehydrate sludge. After being processed, solid content of supernatant in water is ≤0.1, moisture content of sludge cake is 65～85%.
Ⅳ. Parameter of decanter centrifuge applied in power sector
| Model |
Roller diameter mm |
Speed rpm | G-force |
Capacity m3/h |
Dimension mm |
Weight (kg) |
| LW250×1025-N | 250 | 4000 | 1618 | 3-5 | 2840×700×900 | 1200 |
| LW350×1400-N | 350 | 2800 | 1550 | 5-9 | 3620×860×1150 | 2500 |
| LW380×1520-N | 380 | 4000 | 3400 | 9-13 | 2990×1830×1040 | 3500 |
| LW450×1800-N | 450 | 3200 | 2580 | 15-22 | 3234×1910×2415 | 4500 |
| LW530×2120-N | 530 | 2600 | 2006 | 25-45 | 4840×1330×1465 | 5800 |
Ⅴ. Applied cases of decanter centrifuge in all industries
1. Application of LW380×1520-N in power plant
2. Chemical application of LW450×1800-N
3. Juice processing in food industry
4. Scenery of running-water company
8. Production of screw propeller
9. Automatic frequency control BOX
