Typical Applications of Bare Pipe Tube Bundle Coal Economizer

Typical Applications of Bare Pipe Tube Bundle Coal Economizer

The application scenarios of light pipe beam economizer mainly focus on the high ash content, high abrasion, viscous impurities in the flue gas system.

High-ash and high-wear flue gas environment

1. Coal-fired power station boilers and industrial boilers

Background: Coal combustion process generates a large amount of fly ash (ash content is usually 5%-30%), in which hard particles (e.g., SiO₂, Al₂O₃) flow with the high speed of the flue gas, which has a strong scrubbing and abrasive effect on the heated surfaces; at the same time, the fly ash is easy to be deposited on the heat transfer surfaces, which affects the efficiency of heat transfer.

Advantages of light tube:

Smooth tube wall is not easy to retain fly ash, reducing the risk of clogging;

No fin structure, uniform thickness of the tube wall, resistance to fly ash abrasion is much stronger than the finned tube (fin edge is thin, easy to be worn through);

can be efficiently cleaned by steam soot blower, high-pressure water washing and other conventional methods, without worrying about damage to the fins.

2. Biomass boilers (straw, wood chips, rice husk, etc.)

Background: The flue gas produced by biomass combustion contains a large amount of light ash (e.g., potassium and sodium salts) and unburned particles (e.g., charcoal particles), which are easy to slag and have high hardness of the particles, and may also entrain impurities such as straw fibers.

Advantages of fluorescent tubes:

Smooth surface reduces entanglement of fibrous impurities and ash deposition, reducing the risk of localized overheating due to slagging;

High resistance to particle abrasion, adapted to the high abrasion characteristics of biomass flue gases;

Less susceptible to damage due to pulling of impurities during ash cleaning (e.g., mechanical cleaning) (fins can be easily hooked and torn by fibers).

Flue gas containing sticky or corrosive impurities

1. Refuse incinerator

Background: Refuse incineration flue gas is complex in composition, containing sticky tars and chlorinated compounds (HCl) produced by the combustion of plastics and rubbers, as well as hard impurities such as glass and metal, which are prone to scaling and corrosion on the heated surfaces.

Advantages of light tube:

Smooth surface is not easy to adsorb viscous tar, reducing scaling and blockage;

No fin gap, to avoid impurities (such as glass fragments) stuck between the fins to form a local high temperature or corrosion points;

Corrosion resistance is relatively better (no risk of stress corrosion of the edge of the fins), and ash cleaning can be used to completely remove the surface of the adherents of the high-pressure water washing.

2. Heavy Oil / Residual Oil Boilers

Background: Flue gas from heavy oil combustion contains unburned carbon particles, oil mist and sulfur oxides (SOₓ), which are prone to sticky ash buildup and acidic corrosive environments.

Advantages of light pipe:

Smooth surface reduces adhesion of oil mist and carbon particles and reduces heat transfer efficiency degradation due to ash buildup;

More stable resistance to sulfur corrosion (ash buildup between fins exacerbates “under-ash corrosion,” while light pipe has less ash buildup and slower corrosion rates).

Scenarios with loose space and need to control costs

1. Small and medium-sized industrial boilers (e.g., chain furnaces, reciprocating furnaces)

Background: Small and medium-sized boilers have relatively ample space at the tail end, requiring less compactness of the equipment, but need to control the initial investment and maintenance costs.

Advantages of light tube:

Low manufacturing cost (no need for finning process), suitable for scenarios with limited budget;

Simple maintenance (no need for professional tools for ash cleaning and overhauling), suitable for small and medium-sized enterprises with weaker technical force;

Although the volume is large, the heat exchange demand can be met by increasing the length/number of tube bundles, no need to sacrifice the reliability for the compactness.

2. Waste Heat Recovery Retrofit Project (Old Boiler Upgrade)

Background: When old boilers are retrofitted, the space of the tail flue may be irregular and the power of the original induced draft fan is limited (flue gas resistance needs to be controlled).

Advantages of light pipe:

Small flue gas resistance (usually 200-500 Pa), no need to replace high-power induced draft fan, reducing the difficulty and cost of retrofit;

Adaptable, flexible arrangement according to the existing space (e.g., increase the number of rows of tube bundles), without the need to strictly match the compact size.

Scenarios requiring high maintenance convenience

Boilers in remote areas or with limited operation and maintenance conditions: e.g. small boilers in mining areas and rural areas, lacking professional maintenance personnel and equipment. Light tube bundle cleaning is simple (e.g., manual wiping, low-pressure water washing) and is not easily damaged by improper maintenance (finned tube is prone to deformation of fins due to operational errors), which can reduce downtime for maintenance.