ND Steel 09CrCuSb Spiral Finned Low Temperature Economizer

Usage and Application

The low temperature economizer is installed in the tail flue of modern thermal power plants, typically positioned after the air preheater. It extracts the remaining sensible heat from the exhaust gas and drives the gas outlet temperature down to near the acid dew point (about 85°C to 95°C), recovering deep waste heat for feedwater or condensate heating and boosting the overall thermodynamic cycle efficiency.

Manufacturing Capability

• High-frequency resistance welding of spiral fins to the tube for tight, continuous contact
• Precision fin pitch control to balance heat transfer surface and gas-side draft loss
• Specialized welding procedures qualified for ND steel (09CrCuSb) and thin-wall tubing
• Optional fluoroplastic coating line for the most corrosive cold-end environments
• Eddy current and air-tightness testing on every finned tube bundle

Material Specification

Because the tube surface operates where sulfuric acid vapor condenses, ND steel (09CrCuSb) is the preferred metallurgy. It forms a dense, passivated copper-antimony rich layer that significantly slows sulfuric acid corrosion. 316L stainless steel and fluoroplastic-coated carbon steel are offered for extreme sulfur environments.

Typical Parameter Specifications

About Boyu Heavy Industry

Boyu Heavy Industry is a premier global manufacturer of advanced power generation equipment and boiler pressure parts. With decades of thermal engineering expertise, an in-house R&D team and a fully equipped fabrication workshop, we deliver custom-engineered economizers that meet the rigorous commercial operation targets of international power projects.

OEM & Custom Manufacturing

We provide complete OEM and bespoke manufacturing. From material selection and engineering drawings to CNC tube bending, automatic welding, heat treatment and non-destructive testing, every step is controlled in our own plant. Custom tube diameters, wall thicknesses, fin types, header layouts and coil configurations are all available to match your project parameters.

Frequently Asked Questions (FAQ)

Why is ND steel preferred for a low temperature economizer?

ND steel (09CrCuSb) forms a protective, passivated layer when exposed to sulfuric acid, which dramatically slows cold-end corrosion compared with ordinary carbon steel.

Can you match a replacement economizer to an existing plant layout?

Yes. We reverse-engineer the original coil envelope from your drawings or site measurements and supply drop-in replacement bundles that minimize installation downtime.

Do you provide coated tubes for high-sulfur coal?

Yes. For the most aggressive conditions we supply fully polymer-coated (fluoroplastic) heat exchanger tubes on a dedicated coating line.