Design of Gas Condensing Boiler


Gas condensing boiler is a steam boiler that condenses the vapor in the flue gas into water by condenser. It recovers the latent heat released during condensation process, and reuses such heat to achieve 100% or above thermal efficiency.

The flue gas temperature of conventional gas fired boilers is generally 160~250℃. The water produced during fuel combustion becomes vapor in the flue gas and then exhausts via the chimney. The thermal efficiency of conventional gas steam boiler can reach 85~93%. The volume fraction of vapor is about 19%, and is the main carrier of flue gas heat, which can be recovered. Gas condensing boiler is designed based on this concept.

Taishan Group developed a natural gas condensing boiler upon market demand. The flue gas condensing heat recovery device is outside the body. The technical parameters are as follows:

Model: WNS8-1.0-Q

Rated capacity: 8 t/h

Working pressure: 1.0 MPa

Steam temperature: 184℃

Feed water temperature: 20℃

Fuel type: Natural gas (LHV: 35588KJ/m3)

Design efficiency: 101%

Flue gas temperature: 57.2℃

Design of Gas Condensing Boiler

The gas fired boiler includes shell, furnace, reversal chamber, front and rear gas chamber, fire tube, economizer, condenser and base. It adopts corrugated furnace, which not only increases the heating area, but also absorbs the axial expansion. In order to improve the enhanced heat transfer technology, a spiral spoiler is in the fire tube. The high temperature flue gas passes through the furnace, fire tube, front gas chamber, economizer, condenser and chimney.

Main features of condensing steam boiler

(1) Effectively use the latent heat of vaporization to improve the thermal efficiency and reduce the flue gas temperature.

(2) Improved thermal efficiency reduces the fuel consumption and emission of harmful substances such as NOx.

(3) Horizontal full wet back two-pass structure and reasonable heating surface effectively controls the flue gas resistance.

(4) The built-in spiral spoiler improves the heat transfer coefficient of fire pipe, but also inhibits the generation of dirt.

(5) The condenser adopts spiral finned tube, expanding the heat exchange area and enhancing heat transfer effect.

(6) The condenser adopts ND steel, which can effectively prevent the low temperature corrosion from flue gas and condensate.

(7) The economizer and condenser are outside.