Finned Tube----Boiler Economizer
I. What is economizer
Economizer heating surface of boiler feed water is heated in the rear of the boiler flue , boiler feed water before entering the first through it to absorb the heat of the flue gas , reducing the flue gas exhaust temperature , saving energy , improving the efficiency of the so called economizer . ( The word comes from coal-fired boiler economizer , but the system is also used to refer to other fuels economizer )
II. Economizer Category
1 degree water is heated by : Boiling can be divided into ( entering water temperature is the saturation temperature of the steam drum drum under pressure ) and non- boiling type ( entering water temperature is close to the lower drum drum pressure saturation temperature ) .
2 Press the manufacture of materials : There are two kinds of cast iron and steel pipe economizer . Boiling use more non- economizer made of cast iron , but also useful for steel pipe , and boiling economizer can only be made with steel . Cast iron economizer applied pressure ≤ 2.5MPa multi boiler . If the pressure exceeds 2.5MPa, made of steel should be used economizer .
3 in the form of device : There are two types of vertical and horizontal .
4 Press the relative flow of smoke and water supply points: a co-current , counter-flow and hybrid three.
5 According to the structure of the form : finned tubes economizer and economizer . Fin tube economizerinclude : H finned tube economizer ( used more ) and helical fin tube economizer .
III . Economizer role of an improved water temperature
1. reducing water wall stress and improve boiler evaporation ;
2 . Low-temperature flue gas heat absorption , reduce exhaust gas temperature, increase boiler thermal efficiency, fuel savings ;
3. Raising the temperature of the water into the drum will reduce the thermal stress caused by temperature differences , improve the working conditions of the boiler, to extend the service life of the boiler ;
4 . Since the first heated water into the drum before the economizer , thus reducing the water in the heating surface endothermic ,Economizer can be used to replace part of the high cost of heating surface evaporation .
IV . Economizer layout features
( 1 ) counterflow arrangement , increasing the temperature difference ;
( 2 ) water from the bottom up ( following the opening of the inlet pipe , outlet pipe on to ) , to facilitate the discharge of gas , to avoid corrosion ; fumes from top , the soot blowing effect.
V . Role economizer recirculation
In the boiler ( drum boiler ) to start the process, due to the circulation of its soda pipeline did not establish that the boiler feed water at a standstill, this time inside the water economizer is not flowing state , along with the strengthening of the boiler combustion , smoke improve the temperature of the water inside the economizer prone to vaporization , so that local economizer in over-temperature condition. To avoid this situation , from centralized under the water followed by a pipeline to the drum of the economizer inlet , as recirculation pipes, the water is flowing inside the economizer state . Avoid vaporization .
VI. Economizer hydrostatic test should be carried out before installation and bracket installation
Test pressure 1.25P +5 (P boiler working pressure ) no leakage is qualified. Meanwhile economizer safety valve adjustment . Valve opening pressure should be 1.1 times the working pressure of the device points , or 1.1 times the working pressure of the boiler . Location economizer bracket and rear elevation to find a good pouring of concrete , strength grade concrete foundation should be higher than the strength grade level, and should be tamped and Conservation ( when fresh concrete is best to use pisolite ) . When the concrete strength reaches more than 75% , the anchor bolts tightened. Economizer with three wooden tower or other lifting equipment will be installed on the bracket economizer and economizer inspection of imported equipment , the elevation is consistent with the boiler flue outlet and two parts distance and bolt holes are matched by adjusting bracket location and elevation , to the smoke pipe installation requirements