Boiler blowdown heat recovery unit

Posted Date: 08/04/2025 09:23 AM

A single unit can completely replace the conventional system configuration, including in-line expanders, fixed-line expanders, in-line energy absorbers, and fixed-line energy absorbers. It can also eliminate the steam pipeline connecting the in-line expanders to the deaerator in the conventional system, significantly reducing the on-site footprint, pipeline connections, and control valves. This results in a substantial decrease in the infrastructure investment and installation costs for the system.

1. Overview

Boilers of various types require continuous and regular discharge of wastewater with high TDS values and harmful sediments from the boiler drum to ensure steam quality and safety during normal operation. The current practice for treating boiler wastewater typically involves draining it into a continuous drain expansion vessel, flashing off a small amount of steam to be reused in an oxygen-removing unit, and then discharging the remaining, still relatively hot wastewater along with the boiler's regular wastewater into a fixed drain expansion vessel for expansion and pressure reduction. The small amount of steam flashed off is released directly into the atmosphere, while the remaining wastewater around 100°C is cooled by mixing with cold water before discharge or directly into a trench. Due to the working pressure of the oxygen-removing units, especially higher for high-pressure ones, the wastewater discharged from the continuous drain expansion vessel tends to be at a higher temperature. This not only wastes a significant amount of heat energy and high-quality water sources but also contributes to considerable white steam and noise pollution in the surrounding environment due to the large amount of steam released from the fixed drain vessel's top.

2. Boiler effluent recovery unit working principle and technical advantages

To address the existing issues of energy waste and environmental pollution in current technology, Lianyungang Huaneng Power Auxiliary Equipment Co., Ltd. has successfully developed the fifth-generation "Boiler Effluent Energy Recovery Device." Patent Numbers: 201710409090.3, 201720638563.1

One set of this device can completely replace the original conventional system configuration, including in-line expanders, fixed-line expanders, in-line energy collectors, and fixed-line energy collectors. It can also eliminate the steam pipelines connecting in-line expanders to the deaerator in the conventional system, significantly reducing the on-site footprint, pipeline connections, and control valves. This can greatly lower the system's capital investment and installation costs.

3. Classification of boiler waste water recovery systems

To cater to the diverse needs of our clients, we have developed a range of boiler blowdown energy recovery units with four structural types, three pressure levels, ten specifications, and over a hundred models. Additionally, we can customize special specification and model units based on clients' specific requirements.

3.1 By structural type

Structural forms include: built-in cooler with condensation (NN), built-in cooler without condensation (NW), external cooler with condensation (WN), and external cooler without condensation, among the four main categories.

The main purpose of condensate-free systems is for those that require the secondary steam to be discharged as a heat source, such as introducing the secondary steam into a deaerator for use as heating steam. For others, it is generally recommended to use a boiler blowdown recovery unit with an integrated condensate system to ensure no steam emissions.

3.2 Pressure Rating Classification

Pressure grades include Vacuum Type (ZK design pressure -0.1MPa), Atmospheric Pressure Type (CY design pressure 0.1MPa), and Pressure Type (YL design pressure 0.8MPa) in three levels.

3.3 Model Numbering Instructions

4. Boiler Effluent Energy Recovery Unit Outline Drawing

5. Technical specifications to be communicated during order placement

To ensure that the supply equipment offers high cost-performance ratio while meeting the actual operating conditions of the process system, it is best to provide a relatively accurate description of the following process parameters and expectations for the equipment's performance when placing an order:

5.1 Wastewater Treatment Process Parameters

Provide the pressure, temperature, and flow rate of each wastewater stream to be treated, as well as the required pressure and temperature of the treated wastewater.

5.2 Cold Source Process Parameters

Provide import pressure, temperature, and availability of the chilled source (usually demineralized water) that requires heating, as well as the requirements for the chilled source outlet pressure and temperature.

5.3 Requirements for Second-Stage Steam Parameters

Please specify your requirements for the temperature and quantity of the secondary steam if you require it.

5.4 Other Requirements for the Equipment

If needed, please specify various requirements such as the process system combination type, main volume, structural type, design pressure, design temperature, main material, heat exchanger tube material, outer dimensions, pipe end dimensions and orientations, and display and control requirements. Our professional team can tailor-make products and services as close as possible to your expectations.