BOILER ECONOMIZER

A boiler economizer is a heat exchanger installed in the flue-gas path to transfer available exhaust heat to boiler feedwater before it enters the drum or evaporator circuit. The resulting feedwater temperature, stack temperature and effect on fuel use depend on the approved thermal design and actual operating conditions.

Bare tube economizers use plain steel tubes without an extended surface. They are often considered where ash loading, soot blowing and cleaning access are important.

Finned tube economizers use spiral or H-shaped fins to increase external heat-transfer area. Their suitability and resulting footprint or gas-side pressure drop depend on gas cleanliness, fouling risk, tube arrangement and maintenance requirements.

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

• • SA-210 A1 / 20G — Carbon-steel options for conditions permitted by the applicable material standard and design code
• • 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)
• • 09CrCuSb (ND steel) — An acid-resistant steel option for selected low-temperature economizer conditions

Material certificates and traceability records are supplied according to the agreed specification and documentation scope.

For a more detailed technical and commercial review, the following information is 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 general-arrangement drawings or boiler data sheets are unavailable, ORL can first assess whether the available data is sufficient for a preliminary review and identify the missing inputs.

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

An interface review can check header nozzle positions, casing opening dimensions and support-frame compatibility against the submitted information. This helps identify potential fit-up issues before manufacturing scope is confirmed.

Applicable manufacturing and documentation requirements can be reviewed under the following codes and project standards:

• • 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.

The agreed documentation package may include:

• • Material test certificates, including EN 10204 3.1 when specified
• • 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 is project-specific and depends on engineering scope, drawing approval, material availability, bundle size, tube type, inspection hold points, packing and the current production schedule.

For planned outages, please provide the shutdown window during the enquiry stage. ORL will confirm a proposed schedule after the technical scope and required documents are reviewed.

International shipment requirements can be reviewed with Shanghai as a typical port of loading. Depending on the agreed delivery terms, the export scope may include:

• • 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.

HRSG and waste heat boiler economizer sections can be reviewed against the supplied heat-balance data, pressure level, gas conditions, fouling risk and project scope. Single-pressure or multi-pressure arrangements may be considered where technically suitable. Relevant project information can be discussed according to the enquiry requirements.