BOILER ECONOMIZER

A boiler economizer is a heat exchanger installed in the flue gas path downstream of the superheater and reheater. It recovers residual thermal energy from exhaust gases to preheat boiler feedwater before it enters the steam drum. This reduces the amount of fuel required to raise feedwater to steam conditions, improving overall boiler efficiency by typically 2–5% depending on flue gas temperature and water inlet temperature. Economizers also reduce stack gas temperature, which lowers CO₂ emissions per unit of steam generated.

Bare tube economizers use plain steel tubes without any extended surface. They are preferred where flue gas carries significant ash or soot — such as coal-fired or biomass boilers — because fins trap deposits and create cleaning difficulties. Bare tube designs are more robust, easier to soot-blow, and simpler to inspect.

Finned tube economizers attach continuous spiral fins or H-shaped fins to the tube outside surface, dramatically increasing heat transfer area per metre of tube length. This allows a more compact unit with lower gas-side pressure drop. Finned types are ideal for clean-gas applications such as gas-fired boilers, oil-fired boilers, and biomass units with effective particulate control.

Material selection depends on operating pressure, temperature, and flue gas chemistry:

• • SA-210 A1 / 20G — Carbon steel, standard duty up to ~450 °C and pressures below 10 MPa
• • SA-213 T11 / T22 — 1¼Cr and 2¼Cr alloy steels for higher-pressure / higher-temperature units
• • SA-213 T91 — 9Cr-1Mo for supercritical and ultra-supercritical boilers
• • TP304 / TP316 — Stainless steel where corrosive flue gases are present (waste incineration, sulphur fuels)
• • ND Steel / Corten — Low-temperature acid dew-point resistant grades for tail-end condensing economizers

All tube materials are supplied with EN 10204 3.1 mill test certificates and full traceability records.

To provide an accurate quotation, the following information is most useful:

• • Boiler type and fuel (coal, biomass, gas, oil, waste, etc.)
• • Design pressure and operating temperature
• • Feedwater flow rate and inlet / outlet temperature
• • Flue gas flow, inlet temperature and dust loading (if available)
• • New build or replacement — if replacement, existing bundle drawings or dimensions
• • Applicable design code (ASME / GB / EN or project-specific)
• • Required delivery date or outage window

If you have general arrangement drawings or boiler data sheets, please share them. If not, our engineers can work with basic boiler data to develop a preliminary proposal.

Yes — replacement bundles are a significant part of our business. We supply in two modes:

• • Build to print — you provide existing drawings or dimensional survey data and we manufacture to match
• • Reverse engineering — where drawings are unavailable, we review available dimensional data (header centres, tube pitch, nozzle positions) to develop a manufacturing drawing for your approval

Before confirming the order, we carry out an interface review to check header nozzle positions, casing opening dimensions, and support frame compatibility. This step prevents field fit-up problems and is included as standard in our quotation process.

ORL Power is certified and experienced under the main international boiler and pressure vessel codes:

• • ASME Section I (Power Boilers) — with ASME S stamp capability
• • Chinese GB — GB/T 9222, GB/T 5310, TSG G0001
• • EN 12952 — European water-tube boiler standard
• • Project-specific codes confirmed during technical discussion

The applicable code is confirmed during the technical review stage and drives material selection, welding procedure qualification, NDE scope, and documentation requirements.

Standard documentation package includes:

• • Material test certificates (EN 10204 3.1) for all pressure-bearing materials
• • Welding procedure specifications (WPS) and procedure qualification records (PQR)
• • Welder qualification certificates
• • Hydrostatic pressure test report
• • NDE reports (RT / UT / PT / MT as specified)
• • Dimensional inspection report
• • Heat treatment records (where required)
• • As-built drawing

Third-party inspection by SGS, Bureau Veritas, TÜV, Lloyd's Register, or other agencies can be arranged upon request.

Lead time depends on bundle size, tube type, inspection scope, and current production schedule. Typical ranges after drawing approval:

• • Small replacement bundles: 6–10 weeks
• • Medium industrial economizers: 10–16 weeks
• • Large utility / multi-bank units: 16–24 weeks

For planned outages, we ask for the shutdown window date during the enquiry stage so we can build the schedule backwards from your required delivery date. Expedited options are available for emergency replacements — contact us with your situation.

We ship from Shanghai (port of loading) to destinations worldwide. Standard export process includes:

• • Sea-worthy wooden crate or steel frame packing designed for the bundle dimensions
• • Moisture and corrosion protection (VCI film, desiccant)
• • Fumigation certificate (ISPM 15) where required
• • Commercial invoice, packing list, and Certificate of Origin
• • Bill of Lading coordination
• • FORM E (ASEAN-China FTA) or other preferential origin certificates available on request

We work with freight forwarders who specialise in industrial equipment and can assist with door-to-port or CIF arrangements.

Yes. HRSG economizers and waste heat boiler economizer sections are within our standard scope. Key differences from conventional boilers include lower flue gas temperatures, lower tube-side pressures in LP economizers, and sometimes multiple pressure levels (HP / IP / LP). We design each module based on your heat balance data and can supply single-pressure or multi-pressure economizer trains. For metallurgical waste heat boilers (EAF, blast furnace, cement kilns), we have relevant project references.