Boiler blowdown systems remove concentrated water from the boiler to control Total Dissolved Solids (TDS), prevent scale, and maintain steam quality. The blowdown system includes the blowdown valves, blowdown vessel (separator), flash recovery, heat recovery, and the control instrumentation.
AQ Process Systems sources and exports replacement components for all parts of the blowdown system, from the TDS controller and blowdown valves at the boiler, through the blowdown vessel and flash tank, to the heat recovery exchanger and drain cooling system.
Effective blowdown management directly impacts boiler efficiency, excessive blowdown wastes energy and water, while insufficient blowdown causes scale and carryover. We supply the parts that keep your blowdown system operating at peak efficiency.
| Component | Specification | Description |
|---|---|---|
| Blowdown Valves | ||
| Continuous Blowdown Valves | Needle or globe type | SS trim | Modulating | Modulating blowdown valves for continuous surface blowdown, controlling boiler water TDS continuously. |
| Intermittent Blowdown Valves | Quick-opening or slow-opening | CS body | Bottom blowdown valves for periodic sludge removal, quick-opening or slow-opening types. |
| Blowdown Valve Seats & Discs | Stellite-faced or SS | Replacement trim | Valve trim sets (seats and discs) for blowdown valves, hardened for erosion resistance. |
| Blowdown Vessel | ||
| Blowdown Vessel Internals | Baffles, spreader plates | SS | Internal components that distribute incoming blowdown and separate flash steam from liquid. |
| Safety Valves | ASME VIII | Spring-loaded | Overpressure protection for the blowdown vessel, set to vessel MAWP. |
| Vent Pipe & Silencer | CS pipe | Diffuser silencer at discharge | Atmospheric vent pipe with silencer, safely discharging flash steam and reducing noise. |
| Drain Cooling System | Heat exchanger or mixing valve | Blowdown cooling, ensuring discharge to drain is below local temperature limits (typically 43°C). |
| Heat Recovery | ||
| Blowdown Heat Recovery HX | Shell & tube or plate type | SS or CS | Heat exchangers recovering energy from hot blowdown water, pre-heating makeup water or feedwater. |
| Flash Recovery Vessels | Vertical or horizontal | CS | Flash tanks recovering low-pressure flash steam from blowdown for feedwater heating or process use. |
| Control & Monitoring | ||
| TDS Controllers | Conductivity-based | 4-20mA output | Automatic TDS controllers modulating the continuous blowdown valve based on boiler water conductivity. |
| Conductivity Probes | In-boiler or sample-based | High-temperature | Conductivity sensors for boiler water TDS measurement, installed in the boiler shell or sample line. |
| Sample Coolers | SS coil-in-shell | Cooling blowdown sample | Sample coolers for safe collection of boiler water samples for laboratory analysis. |
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.
The main spares are blowdown valves and trim sets (erosion from high-velocity flashing water), TDS controllers and conductivity probes (scaling and drift), blowdown vessel internals (corrosion), safety valves (periodic recertification), vent silencers (corrosion), and heat recovery exchanger gaskets or tubes.
Blowdown valve seats and discs are subject to severe erosion from high-velocity flashing water. Trim sets typically need replacement every 1-3 years depending on blowdown frequency and pressure drop. The valve body usually lasts much longer. Inspect trim during annual boiler shutdowns.
Yes. We supply shell & tube and plate-type heat exchangers for recovering energy from boiler blowdown. These pre-heat incoming makeup water using the hot blowdown, recovering 60-80% of the blowdown energy. We also supply replacement flash recovery vessels for low-pressure flash steam recovery.
Most jurisdictions require blowdown to be cooled below 43°C (110°F) before discharge to drain. We supply blowdown cooling systems, either mixing-type (blending with cold water) or heat exchanger type (recovering the heat into makeup water). The heat exchanger approach is preferred as it recovers energy.
The TDS controller measures boiler water conductivity (which correlates with Total Dissolved Solids) using a conductivity probe installed in the boiler or sample line. When the TDS exceeds the setpoint, the controller opens the continuous blowdown valve to discharge concentrated water. When TDS drops below setpoint, it closes the valve. This maintains optimal boiler water chemistry automatically.
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