1.
Air preheater, also referred to as air preheater for short, is a preheating device that improves the heat exchange performance of boilers and reduces heat loss. The function of the air preheater is to conduct the heat carried in the flue gas discharged from the tail flue of the boiler to the air before entering the boiler through the heat sink, and preheat the air to a certain temperature.
Generally referred to as air preheater. It is mostly used in coal-fired power station boilers. It can be divided into tube box type and rotary type, and the rotary type is divided into two types: wind cover rotary type and heating surface rotary type. Power plant boilers often use rotary preheaters on the heating surface. The application in the boiler is generally two compartments, three compartments, and four compartments, among which the four compartments are more commonly used in circulating fluidized bed boilers.
The air preheater is generally installed on the tail flue of the boiler, and both the flue gas and the air side use finned tubes for heat exchange to enhance heat transfer performance. Generally, heat pipes are used as heat transfer elements. In order to prevent dew point corrosion and maintain good heat transfer characteristics of finned tubes, a special air preheater consisting of two parts, an evaporator and a condenser, can be used to form a separated phase-change heat system. In this special heat exchanger, the evaporator is located in the lower flue, and the condenser is located above the flue. Both the evaporator and the condenser are composed of finned tube bundles, and each row of tube bundles is interconnected by upper and lower headers.
HEXIN uses resin sand technology and automatic production equipment, it can realize automatic sand distribution, sand filling, molding, hardening, demoulding and sand regeneration, and can continuously produce casting heat transfer plates with high efficiency and stable quality.
High production efficiency, stable casting quality, high surface quality, uniform and dense internal structure, no blisters, slag inclusions, pores, cracks and other defects. Can guarantee product quality and long service life.
Structural features
a) The double-sided fin cast plate air preheater is composed of multiple cast heat transfer fins in different ways to form a single-pass or multi-pass whole;
b) Each cast heat transfer plate is cast, and the plates are connected by bolts;
c) Double-sided fin casting The single heat transfer fin of the plate air preheater is made of pre-made steel abrasives, and the double-sided finned heat transfer plate is a one-time integral casting, which can ensure the integrity of the airtightness.
d) Compact structure and small footprint;
e) Modular structure, suitable for assembly and transportation.
3. Thermal properties
a) The heat transfer coefficient is high, and the general tube bundle air preheater cannot be compared with the heat pipe air preheater;
b) Good air tightness;
c) Under the same operating conditions, the cast air preheater has a longer life than the carbon steel air preheater.
2.
HEXIN producs various designs of Plate Air Preheaters, typical designs as below:
The basic form of the plate air preheater belongs to the plate heat exchanger. The heat exchange element is made of cold-rolled thin steel plate. The mainstream air preheater form in recent years.
Tube Bundle/Spoiler Air Preheater
Tube bundle/spoiler air preheater is a traditional form of air preheater with mature structure and easy maintenance. Spoilers enhance heat transfer.
Cast iron plate air preheater
The cast iron plate air preheater has excellent anti-dew point corrosion performance, greatly reduces the exhaust gas temperature, significantly improves the efficiency of waste heat recovery, and prolongs the operation period. The heat exchange element is a double-sided finned alloy ductile iron plate, which has the characteristics of high heat exchange efficiency, resistance to dew point corrosion and not easy to accumulate dust.