Feedwater heaters are critical components in the power plant steam cycle, improving thermal efficiency by preheating boiler feedwater using extracted steam from the turbine. Their reliability directly impacts plant heat rate, fuel consumption, and generating capacity.
AQ Process Systems sources and exports replacement tubes, tube sheets, water box components, and internals for both LP (low-pressure) and HP (high-pressure) feedwater heaters. We source tubes in stainless steel, copper alloys, and titanium to match the original heater specification.
For power plant outage planning, we provide consolidated feedwater heater spares packages covering tubes, gaskets, safety valves, and instrumentation, timed to arrive before your scheduled outage window.
| Component | Specification | Description |
|---|---|---|
| Tubes & Bundles | ||
| Feedwater Heater Tubes | SS 304/316, Cu-Ni 90/10, 70/30, Ti, Monel | U-tube or straight | Replacement tubes in copper alloy, stainless, or titanium, U-bent or straight, with post-bend treatment. |
| Complete Tube Bundles | Re-tubed assemblies | Hydro-tested | Factory re-tubed bundles with new tubes, baffles, support plates, tested and ready for installation. |
| Tube Sheets | SA 266, SA 508, or clad | Drilled to OEM pattern | Forged tube sheets, drilled, clad (if applicable), and machined to OEM specifications. |
| Internal Zones | ||
| Desuperheating Zone Baffles | SS plate | Directing extraction steam flow | Baffles in the desuperheating zone directing superheated extraction steam for initial heat recovery. |
| Condensing Zone Baffles | CS or SS | Supporting tubes in main condensing section | Tube support baffles in the main condensing zone, segmental or disc-and-donut configuration. |
| Drain Cooler Tubes / Baffles | Separate zone or integral | CS or SS | Drain cooler (subcooling) zone internals, baffles, shrouds, and partition plates. |
| Impingement Plates | SS plate | Steam inlet protection | Erosion protection at the extraction steam inlet nozzle, preventing direct impingement on tubes. |
| Water Box & Channel | ||
| Water Boxes / Channel Heads | CS or SS | Hemispherical or dished | Feedwater inlet/outlet water box assemblies, replacement or refurbishment of corroded units. |
| Water Box Gaskets | Spiral wound, kammprofile | High-pressure rated | Main joint gaskets between water box and tube sheet, rated for HP heater operating pressures. |
| Pass Partition Plates | CS or SS | Multi-pass water box configuration | Tube-side pass partition plates dividing the water box into inlet and outlet passes. |
| Safety & Instrumentation | ||
| Shell Relief Valves | ASME VIII | Spring-loaded | Shell-side overpressure protection, protecting against tube rupture flooding the shell with high-pressure feedwater. |
| Level Controls | DP or displacer type | Shell-side condensate level | Normal level, high level, and emergency drain level controls for the heater shell condensate. |
| Drain Valves | Control valves | Normal and emergency drain | Normal drain control valves and emergency drain valves for heater shell condensate management. |
Parts are matched to OEM material specifications and dimensional tolerances. Please provide the equipment manufacturer, model number, and serial number (if available) for precise part identification. Mill Test Certificates (MTC) supplied with all tube materials per EN 10204 3.1.
The most frequently replaced parts are tubes (erosion-corrosion, especially in the drain cooler zone and U-bend area), tube support baffles (vibration wear), water box gaskets (replaced every opening), shell relief valves (periodic testing/recertification), and level control instruments (calibration drift). Tube plugging is performed as an interim measure before complete re-tubing.
LP heaters commonly use copper-nickel (90/10 or 70/30), while HP heaters typically use stainless steel (304/316) or titanium. The trend is toward all-stainless or titanium to eliminate copper transport to the boiler. AQ Process Systems sources and exports all metallurgies with full certification for power plant code compliance.
For emergency situations where tubes are leaking, the immediate action is tube plugging (blocking both ends of the failed tube with tapered plugs). We supply tube plugs in the correct size and material. For planned outages, we supply complete re-tubed bundles or individual replacement tubes for partial re-tubing.
Each plugged tube reduces the heater's heat transfer capacity, increasing the feedwater temperature shortfall. This means the boiler needs more fuel to reach the same steam conditions, increasing heat rate (kJ/kWh). When the number of plugged tubes exceeds 10-15% of the total, re-tubing is typically justified by the fuel cost savings.
Yes. We supply spares for both low-pressure (LP) and high-pressure (HP) feedwater heaters. LP heaters typically operate at 5-15 bar and use copper-nickel or stainless tubes. HP heaters operate at 80-200+ bar and require higher-grade materials and forged components. We match all parts to the heater's design pressure and operating conditions.
Share your equipment make, model, and part numbers, we respond within 24 hours.