Deaeration Purpose

Water absorbs oxygen and carbon dioxide causing severe boiler corrosion. Chemical treatment alone cannot remove all dissolved gases. Thermal deaeration heats water releasing gases to atmosphere or vent eliminating corrosion before water enters boiler.

Operating Principle

Steam heats incoming feedwater to saturation temperature typically 110-120C. At saturation, gas solubility drops to near zero. Dissolved oxygen and CO2 release as vapor. Vent removes released gases. Deaerated water collects in storage section maintaining temperature.

Vessel Configuration

Horizontal or vertical pressure vessel combining deaeration section and storage tank. Steam inlet heating feedwater, spray or tray section maximizing gas release surface area, vent removing gases, deaerated water storage, outlet to boiler feed pumps.

Operating Pressure

Typical 5-20 psig provides saturation temperature adequate for deaeration. Higher pressure deaerators operate to 50 psig for specific applications. Pressure maintains water temperature preventing oxygen reabsorption.

Deaeration Efficiency

Reduces dissolved oxygen to under 7 ppb, often below 5 ppb meeting boiler requirements. Removes carbon dioxide and non-condensables. Performance depends on proper steam flow, water distribution, and vent operation.

Material Selection

Carbon steel construction per ASME Section VIII suitable for feedwater and steam service. Internal components resist erosion from spray and steam. Design handles thermal cycling during operation.

Storage Section

Integral storage maintains deaerated water inventory at temperature. Provides pump suction with adequate NPSH. Typical storage 5-10 minutes boiler demand. Level control manages inventory coordinating makeup with steam production.

Applications

Power plant boiler feedwater treatment, industrial boiler systems, district heating plants, process steam generation, and any facility requiring corrosion-free feedwater for steam boilers.

Steam Consumption

Requires 1-3% steam based on feedwater flow for heating and deaeration. Some designs use extraction steam from turbines improving plant efficiency. Steam cost offset by eliminating chemical deaeration and preventing boiler corrosion.

Vent System

Continuously removes released gases preventing reabsorption. Vent rate balances gas removal versus steam losses. Proper operation critical for achieving target oxygen levels.

Level Control

Makeup water addition maintains storage level. Controllers coordinate with boiler demand. High-level prevents overflow. Low-level protects feed pumps from cavitation or loss of suction.

Performance Benefits

Eliminates oxygen corrosion extending boiler life decades. Reduces chemical treatment costs. Improves heat transfer by removing gas films. Proven technology essential for quality steam systems.

Construction Standards

Design per ASME Section VIII for pressure service. Relief protection per boiler codes. Materials for feedwater and steam. Complete documentation with deaeration performance guarantees.

ERGIL deaerator vessels protect boilers through thermal oxygen removal delivering corrosion-free feedwater in power generation and industrial steam applications.