High frequency resistance welded spiral fin tube Superheater And
Reheater heat exchanger
Product Description
High frequency resistance welding spiral finned tube is to
introduce high power high frequency current into the welded part,
use the current through the contact surface of the welded part and
the adjacent area generated resistance heat to make the welding
contact surface to melt or semi-melt plastic state, and then apply
appropriate pressure to the welding contact surface, so as to
complete the finned tube welding work.
The heat transfer effect of high frequency resistance welding and
brazing spiral finned tube is at least 4 times higher than that of
plain tube.
To improve the thermal efficiency, the pressure of superheated
steam have been increased from superhigh pressure to subcritical
and supercritical pressure. But limited by the metal performance,
the steam temperature of superheaters and reheates are kept within
540-555 degrees.
Because what flow through tubes of superheaters and reheaters are
high temperature steam, the convective heat release transfer
coefficient of tube wall to steam is quite small, and heat transfer
performance is poor, the cooling capacity of steam to tube wall is
low. Meanwhile, to make sure reasonable temperature difference of
heat transfer, usually superheaters and reheaters are placed at the
areas where smoke temperatures are high, and their working
temperature of tube wall is rather high, thus the working
environment of superhearters and reheaters are quite bad.
Especially reheaters, for reheated steam pressure is low, and their
capacity to cool tubes are worse, thus that how to make sure tube
metal can be safe working on the long term is an important issue
when comes to design and operation of superheaters and reheaters.
Diagram 4-1 lists the upper limit of allowable temperatures for
common metal used in boilers. To avoid use of higher level of alloy
steel, when it comes to design of superheaters and reheaters, used
tube metal are almost close to the temperature limits when working.
This time, if there is rise of temperature of 10-20 degrees, which
also reduces the allowable stress a lot. Therefore, Attention
should be paid for the design and running of superheaters and
reheaters in aspects below:
1.to make sure the steam temperature stable when running. The variation of steam temperature is
supposed to be not over+5- -10 degrees;
2.There needs reliable method to adjust temperatures for
superheaters and reheaters when operation conditions changes to
some extend to maintain rated steam temperatures.
3. to minimize the thermal deviation between parallel tubes.
Application
use for heating saturated steam, steam temperature could be up to
900 degree C.
Superheater Capacity Upgrades to Increase Power Generation
Send us required technical data, such as steam capacity, presure,
required temperature etc. We will design accordingly.
Differences
| Type | Advantages | Disadvantages | Supporting method |
| Pendant-type | 1.Firm structural support | 1. Flow blockage by condensed steam 2. Needs slow restart to purge
the water that accumulates in the bottom. | supported from above |
| Inverted-type | 1.Proper drainage of the condensed steam | 1. Lack the structural rigidity, especially in high speed gas flow | Supported from below |
| Horizontal -type | 1. Proper drainage 2. Good structural rigidity. | 1. 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. |
Superheater is to increase the temperature of the steam above its
saturation point.
Reheater is basically a superheater that superheats steam exiting
the high-pressure stage of a turbine. The reheated steam is then
sent to the low-pressure stage of the turbine. By reheating steam
between high-pressure and low-pressure turbine it is possible to
increase the electrical efficiency of the power plant cycle beyond
40%.The reheat cycle is used in large power boilers since it is
feasible economically only in larger power plants.
Details
All the raw materials will be firstly made pipeline cutting.
It is consisted of a series of bare oil(carbon steel,alloy steel,or
durable heat steel) and header and other auxiliaries.
TubesΦ32,38,42 and so on,also as the request.
Setting Information |
process | welding |
structure | horizontal or vertical |
material | carbon steel, alloy steel |
tubes | φ32, 38, 42, etc. |
size | customized |
brand | HTEG |
Warranty | 18 months |
Differences
| Type | Advantages | Disadvantages | Supporting method |
| Pendant-type | 1.Firm structural support | 1. Flow blockage by condensed steam 2. Needs slow restart to purge
the water that accumulates in the bottom. | supported from above |
| Inverted-type | 1.Proper drainage of the condensed steam | 1. Lack the structural rigidity, especially in high speed gas flow | Supported from below |
| Horizontal -type | 1. Proper drainage 2. Good structural rigidity. | 1. 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. |
Application
Use for heating saturated steam, steam temperature could be up to
900 degree C.
Superheater Capacity Upgrades to Increase Power Generation
Workshop
Send us required technical data, such as steam capacity, presure,
required temperature etc. We will design accordingly.
Company Introduction
Established in 1985,Zhangjiagang Hua Dong Boiler Co.,Ltd.(trading
as HD Boiler),produces power plant; industrial; waste heat; waste
incineration; biomass; organic heat carrier and electric steam
boilers. Coupled with a comprehensive range of heating surfaces, HD
Boiler brings to the market a unique service including boiler
design , fabrication, installation, maintenance and replacement of
boiler pressure parts.
1. Fabrication area of 200,000 square meters
2. 150 Engineers
3. 600 Coded welders
4. 60 Licensed Inspectors(NDT Level-III instructors)
5. Class-A Licenses for Design and Manufacture Boiler
6. ISO 9001:2008 Quality System
7. ASME Certificate of Power Boilers
8. ASME 'S','U' and NB stamp authorization
