Waste Energy Recovery Solution Customized Superheater And Reheater Systems

Waste Energy Recovery Solution Customized Superheater And Reheater Systems

How does a reheater differ from a superheater?

A reheater reheats steam after partial expansion in turbine, while superheater heats saturated steam from boiler drum.

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Product Functions of Superheater and Reheater

Superheater

1.The function of the superheater in the thermal power plant is to remove the last traces of moisture ( 1 to 2%) from the saturated steam coming out of boiler and to increase its temperature sufficiently above saturation temperature.

2.The super-heating heating raises overall overall cycle efficiency efficiency as well as avoids too much condensation in the last stages of the turbine which avoids the blade erosion.

3.The heat of combustion gases from furnace is utilized for the removal of moisture from steam and to superheat the steam.

4.Super-heaters usually have several tube circuits in parallel with one or more return bends, connected between headers.

Reheater

1.The function of the re-heaters is to resuperheat the partly expanded steam from the turbine.

This is done so that the steam remains dry as far as possible through the last stage of the turbine.

2.Location: Before or after the convective superheater in the convective zone of utility boilers. In modern high pressure boilers, reheaters are generally in two sections.

3.The primary section is placed in the convective zone and secondary section is placed just at the furnace exit hanging from the top.

4.The design consideration for reheaters are similar to those for superheaters.

5.It having same output temperatures but steam pressures are about 20-25% of those in superheaters. Hence lower grade steel alloy can be used for reheaters.

Type Advantages Disadvantages Supporting method

Pendant-type

1.Firm structural support

2. Flow blockage by condensed steam

3. Needs slow restart to purge the water that accumulates in the bottom. supported from above

Inverted-type

1.Proper drainage of the condensed steam

2. Lack the structural rigidity, especially in high speed gas flow Supported from below

Horizontal -type

1. Proper drainage

2. Good structural rigidity.

They do not view the flam directly so they are mainly from the convective type Usually supported in the vertical gas ducts parallel to the main furnace.

Details of Superheater and Reheater

Manufacturing and acceptance criteria of Superheater and Reheater

1.JB/T1611 " Technical specification for manufacturing of boiler pipes."

2.JB/T1612 "boiler pressure test technical conditions. "

3.JB/T1613 "Technical specification for welding of pressure parts of boiler."

4.JB/T1615"Technical specification for painting and packing of boiler."

5. JB/T3375 "Rules for receiving acceptance of materials for boiler construction."