Recover Waste Heat from Hot Flue Gas and Industrial Processes

ZZ Thermal Waste Heat Recovery Heat Exchangers are designed to recover thermal energy from hot flue gas, exhaust gas and

 other industrial process streams.

Using laser-welded Pillow Plate heat transfer technology, the system transfers heat from hot gases to water, thermal fluids, air or

 other suitable heat transfer media.

The recovered energy can be reused for process heating, hot water generation, feedwater preheating, combustion-air preheating,

 space heating or other thermal processes, helping industrial plants improve overall energy efficiency and reduce fuel consumption.

The system can also be configured as a flue gas condenser when heat recovery below the flue gas dew point is required.

How Does It Work?

Hot flue gas passes through the gas-side channels of the heat exchanger while a heat transfer medium flows inside the Pillow Plate

 panels.

Heat is transferred indirectly through the metal plate surfaces without direct contact between the flue gas and the recovered fluid.

Depending on the process requirements, the system can be designed for:

﹡Gas-to-water heat recovery

﹡Gas-to-thermal-fluid heat recovery

﹡Gas-to-air heat recovery

﹡Flue gas condensation

﹡Multi-stage heat recovery

For condensing applications, the heat exchanger can recover both sensible heat and latent heat from the flue gas, increasing the

 overall heat recovery potential.

Pillow Plate Technology for Waste Heat Recovery

The heat transfer core consists of laser-welded Pillow Plate panels.

The Pillow Plates provide a large effective heat transfer surface while allowing flexible channel geometry and compact equipment 

configurations.

The all-welded construction eliminates conventional gaskets and adhesives from the heat transfer surfaces and provides a robust 

solution for demanding industrial applications.

Depending on gas composition, temperature and operating conditions, suitable stainless steels and other alloys can be selected for

 the heat transfer surfaces.

Typical materials include:

﹡AISI 304

﹡AISI 316L

﹡Duplex stainless steels

﹡Titanium

﹡Other corrosion-resistant materials according to process requirements

Key Advantages

High Heat Recovery Efficiency

The large heat transfer surface enables efficient recovery of thermal energy from hot gas streams and industrial exhaust.

Compact and Modular Design

Pillow Plate modules can be arranged in banks and configured in vertical or horizontal layouts according to available space and 

required heat transfer capacity.

Corrosion-Resistant Construction

Stainless steel and other suitable materials can be selected according to flue gas composition, temperature, moisture and corrosive

 components.

Suitable for Difficult Flue Gas

The equipment can be designed for industrial exhaust containing moisture, dust and potentially corrosive components, subject to 

detailed process conditions.

Flue Gas Condensation

For suitable applications, the heat exchanger can operate below the flue gas dew point to recover additional latent heat from water 

vapor.

Customized Heat Transfer Design

Heat transfer area, channel geometry, material, gas velocity and pressure drop can be engineered according to the actual operating

 conditions.

Reduced Energy Consumption

Recovered heat can replace part of the energy otherwise supplied by boilers, heaters or other fuel-consuming equipment.

Reduced Environmental Impact

By recovering energy that would otherwise be discharged through the exhaust system, the technology can help reduce fuel 

consumption and associated CO₂ emissions.

Typical Applications

ZZ Thermal Waste Heat Recovery Heat Exchangers can be applied to a wide range of industrial processes, including:

Cement Plants

Recovery of heat from kiln, preheater, cooler or other high-temperature exhaust streams.

Steel and Metallurgical Industries

Recovery of thermal energy from furnaces, process exhaust and other high-temperature gas streams.

Industrial Furnaces

Recovery of heat from furnace exhaust for process heating, combustion-air preheating or hot water generation.

Chemical and Petrochemical Plants

Heat recovery from process gases and exhaust streams containing moisture or corrosive components.

Waste Incineration

Recovery of thermal energy from combustion and flue gas streams.

Food and Pharmaceutical Industries

Recovery of heat from dryers, ovens, boilers and other thermal processes.

CHP and Cogeneration Plants

Recovery of residual heat from exhaust gases and combustion processes.

Typical Heat Recovery Applications

The recovered heat can be used for:

﹡Hot water production

﹡Process water preheating

﹡Boiler feedwater preheating

﹡Combustion-air preheating

﹡Process heating

﹡Thermal oil heating

﹡Space heating

﹡Other plant utility systems

Flue Gas Condensers

When the flue gas is cooled below its dew point, water vapor contained in the gas condenses and releases additional latent heat.

A properly designed Pillow Plate flue gas condenser can therefore recover both sensible and latent heat.

This configuration is particularly attractive where a continuous demand for low-temperature hot water or other low-grade heat is 

available.

The design must consider:

﹡Flue gas composition

﹡Dew point

﹡Moisture content

﹡Acid dew point

﹡Dust concentration

﹡Gas temperature

﹡Corrosion risk

﹡Condensate drainage and treatment

﹡Allowable pressure drop

For corrosive flue gas, appropriate materials and operating temperatures must be selected to minimize corrosion risk.

Performance and Energy Savings

The achievable heat recovery depends on the actual gas flow rate, inlet and outlet temperatures, gas composition, moisture content,

 heat transfer medium and allowable pressure drop.

ZZ Thermal designs the heat exchanger according to the required thermal duty rather than applying a fixed configuration.

For each project, the design can be evaluated based on:

﹡Flue gas flow rate

﹡Gas inlet temperature

﹡Required gas outlet temperature

﹡Heat transfer medium and flow rate

﹡Medium inlet and outlet temperature

﹡Required heat recovery duty

﹡Gas composition

﹡Dust loading

﹡Pressure drop

﹡Available installation space

Customized for Your Process

Every waste heat recovery application is different.

ZZ Thermal can provide customized Pillow Plate heat exchanger designs based on the actual process conditions, including heat

 transfer area, material selection, flow configuration, pressure drop and equipment dimensions.

Both vertical and horizontal configurations are available, and modular heat exchanger banks can be configured according to the

 required capacity and installation conditions.

Improve Your Plant's Thermal Efficiency

If your plant is discharging hot flue gas or process exhaust, there may be an opportunity to recover part of this wasted thermal 

energy.

Send us your gas flow rate, inlet/outlet temperature, gas composition and available heat sink, and our engineers can evaluate a 

suitable Pillow Plate Waste Heat Recovery solution.