Transforming lost thermal energy into sustainable power.
Most industrial processes rely on equipment such as furnaces, kilns, heaters, boilers, internal combustion engines, and gas turbines. These systems typically combust fossil fuels like coal, oil, or natural gas. During this combustion, only a portion of the atmospheric oxygen is utilised, with the remaining gases released as exhaust flue gases.
These flue gases absorb a significant amount of the energy generated, often between 20% and 50% of the total energy from fossil fuel combustion. Their temperatures typically range from 150 °C to 400 °C. This heat, contained within the flue gas, is often wasted and lost to the atmosphere.
It is possible to recover this wasted heat through technological intervention and convert it into usable power. When flue gas temperatures exceed 300 °C, the heat can be efficiently recovered using a Heat Recovery Steam Generator (HRSG) to generate power via a conventional Rankine cycle power plant.
However, conventional Steam Rankine Cycle power plants may not be feasible if the flue gas temperature is below 250 °C to 300 °C. Furthermore, certain industries, such as petroleum refineries, have liquid process streams with temperatures ranging from 120 °C to 250 °C that require cooling before storage. This highlights a critical need for advanced technologies capable of capturing this valuable low-grade heat from both flue gases and liquid streams.
At First ESCO, we offer proprietary, patented technology to recover this low-grade heat and convert it into power using Organic Rankine Cycle (ORC) power systems. The instrument below is our process, drawn to scale of principle: follow the heat from the flue duct, through the thermal-oil loop, into the organic fluid that spins the turbine.
Hover or tap any component to read its role. Use the controls to pause or change speed.
Beyond continuous heat streams, we also provide advanced technologies for Thermal Energy Storage, particularly for intermittent heat sources. A prime example is heat recovery from Electric Arc Furnaces (EAF) in steel melting. While off-gas temperatures from EAFs can reach around 1400 °C, the heat availability is intermittent, as steel is melted in batches (known as "heats"). Currently, due to this intermittent nature, off-gases are often cooled using energy-consuming forced draft heat exchangers, rather than recovering their valuable heat.
Our Thermal Energy Storage solution is ideally suited for these scenarios. It allows for the recovery and storage of high-temperature heat during a "heat cycle" when hot gas is available. This stored heat can then be utilised continuously, even when no off-gas is being produced. This presents a significant opportunity for the steel industry to recover valuable heat, generate power, and thereby reduce their specific carbon emissions — mitigating disadvantages arising from regulations such as the Carbon Border Adjustment Mechanism (CBAM) imposed by European customers.
The store absorbs each furnace batch and discharges between them — watch the level: the input stops, the output never does.
This is not a concept. Our 2.9 MW ORC waste heat recovery plant has been operating in the UAE since 2017, recovering low-grade heat that was previously vented, and returning it as power, day after day.
For the full engineering story, cycle selection, thermal energy storage design and project economics, our presentation covers the WHR-ORC system in depth.
If you would like to calculate the potential revenue from your waste heat recovery system using ORC, we have developed a specialized tool that can assist you in estimating the financial benefits of implementing our ORC systems.