The waste heat boiler of QC120/1000-50-3.82/450 type is a device which generate superheated steam using industrial waste heat furnace gas containing micro dust . The characteristics of the waste heat boiler are as following：
1. Energy saving, realizing the comprehensive utilization of heat energy. The waste heat boiler uses the waste heat of industrial exhaust flue gas containing dust to generate superheated steam for power、production and living. The boiler don’t directly use the disposable fuel, so it has the characteristics of energy saving and comprehensive utilization of energy.
2. Dedusting in furnace is beneficial to environmental protection. Industrial gas containing dust contains a large number of particle dust. The boiler adopts inertia separation principle using gas turning in the bottom of superheater and economizer in the boiler interior separating gas and dust in order to reduce the ash content.
3. The resistance is low. Boiler body adopts the design such as velocity and low velocity. The body wiht small resistance combining with other equipments can reduce the system power consumption.
4. The boier structure is compact, and appearance is neat .
Design Parameters and Basis
Boiler safe operating conditions range：heating load 50%～100%
(1)rated output 50t/h
(2)rated steam pressure 3.82MPa
(3) rated steam temperature 450℃
(4)feed-water temperature 104℃
(5) blowdown rate 2%
(6) exhausted gas temperature ～180℃
(7)boiler excess air coefficient 1.015
(8) boiler thermal efficiency 81.8%
(B)Inlet gas parameters
(1) Inlet gas flow 120000 Nm3/h
(2)inlet gas temperature 1000 ℃
(3) gas dust content 500mg/Nm3
(C)Inlet gas composition(%)
N2 : 71.8%
The boiler is double drum and horizontal natural circulation water boiler. The gas containing dust flows out of furance access to screen tubes, superheater, convection bank, steel tube economizer.
The boiler screen tubes are made into by pulling the front wall tube dilutly. Inlet gas turning 90 ° flows into the upper space of the superheater after lateral erosion.
Superheater adopting the level suspension structure and coils are divided into high temperature and low temperature section . High temperature section uses 12Cr1MoVG high pressure boiler tube, and the low-temperature section adopts 12Cr1MoVG high pressure boiler tube and in-line layout. Desuperheating spray way between the two stage superheater is used to adjust the superheated steam temperature. Flue gas turningto 90° in the bottom of the superheater flows into the upper of convection bank.A part of the fly ash due to the inertia force is separated and concentrates in the bottom ash hopper. So it can be manually clean periodically. The saturated steam isolated by drum flows into superheater header import with the guide tube. Then through the low temperature superheater it enters the spray type attemperator. The desuperheating saturated steam flows into the inlet heater at the high temperature period , then enters the high temperature superheater, and is guided out through the superheater outlet header after reaching rated export parameters.
There are main steam valve, safety valve, pressure gauge, thermometer, backwash, fire exhaust steam, steam trap, etc in the superheater outlet header.
Pipe connecting the drum makes into convection bank.The convection bank adopts 20 (GB3087-2008) boiler pipes and in-line arrangement. The the middle deflection generated by deflecting baffles at two sides of gas in to improve gas velocity and form effective lateral erosion improving the heat transfer capacity of convection bank. Boiler water in the pipe line made by drum and convection banks flows in the form of natural circulation using the density difference. Flue gas downwards into the transient duct in the level export on the convection bank by a 90 ° turing.
Economizer adopts 09CrCuSb(GB150-2011) high quality boiler coil tubeφ32, and lateral erosion and counterflow arrangement. The flue gas flows top-down. Economizer tubes chooses ND steel to prevent low temperature corrosion. Boiler feed water follows into the drum access to economizer inlet header, economizer piping, the economizer outlet header.
The upper drum diameter is 1400 mm, and is welded into by Q345R boiler plates. The lower drum diameter is 1000 mm , is welded into by boiler plates. The upper drum is put on the two drum support in steel framing freely and can expand freely. There are separation devices such as the cyclone separator, the top corrugated board, board, perforated plate, etc in the upper drum. Steam water mixture following into the drum blocked into the moisture separator after resisted by the baffle first and is separated once, Then the steam water mixture entering the top undulated separator goes on secondary separation. The blowdown tube and drainage tube are installed in order to improve the steam quality.
Inner layer of boiler front and back wall is light armor plate furnace wall made of aluminium silicate refractory fibre and insulation brick. The inner layer of bilateral wall adopts refractory brick layer,The middle layer adopts aluminum silicate fiber layer, and the outermost layer is the heavy wall structure of red brick. The boiler is packaged by corrugated board around, and its appearance is beautiful and easy.
Boiler Supply and Complement
The regulations of boiler supply scope and complete auxiliaries are as follows(or supplied according to the purc contract):
1. The boiler products, components are supplied according to the shipping list.
2. Piping accessories of boiler body , part of raw materials supplies, pipe bending and installation at site.
The complete auxiliaries are supplied by the contract according to specific situation.