Industrial plants often vent substantial quantities of low-pressure steam to atmosphere, resulting in the loss of valuable energy, water and water-treatment chemicals. Recovering the latent heat contained within this low-pressure steam can significantly reduce boiler load, improve overall plant efficiency and deliver measurable fuel cost savings.
Low-pressure steam can be reused across a wide range of process duties, including evaporation, distillation, hot water generation, space heating, vacuum production and water chilling. Where the available steam pressure is insufficient for the intended process, a New Field Steam Jet Thermocompressor can increase both pressure and temperature to the required operating level.
Thermocompressors and ejectors operate on the same fundamental thermodynamic principle. Energy from high-pressure motive steam is transferred to a lower-pressure vapour or gas stream, producing a mixed discharge flow at an intermediate pressure.
These systems are valued for their simple construction, ease of installation, minimal maintenance requirements, absence of moving parts, resistance to fouling, low capital cost and long operating life.
When the purpose is to recover latent heat from low-pressure suction vapour for process use, the equipment is known as a Thermocompressor. When the purpose is to create vacuum in a process vessel, the same principle is applied in the form of a steam jet ejector.
Single-stage and multi-stage Thermocompressors are used to convert low-pressure vent steam into valuable process steam at a higher pressure and temperature. Where high-pressure motive steam is available, Thermocompressors provide an efficient and economical solution for steam recovery and pressure boosting.
High-pressure motive steam enters the Thermocompressor and expands through a converging-diverging nozzle, converting pressure energy into high-velocity kinetic energy. Low-pressure vent steam is then drawn into the suction chamber and entrained into this high-velocity jet. The two streams mix thoroughly before passing through the diffuser, where kinetic energy is converted back into pressure energy.
The resulting discharge steam is delivered at an intermediate pressure between the motive steam pressure and suction steam pressure. Final performance is determined by the motive steam pressure, suction steam conditions, discharge pressure requirement and available steam flow.
New Field Thermocompressors are suitable for a broad range of industrial steam recovery and process applications, including:
An industrial facility venting 10,000 lb/hr of steam at near-atmospheric pressure can recover this otherwise wasted energy by using a Thermocompressor to raise the steam to a useful process pressure. In this example, low-pressure steam at approximately 0.3 psig is boosted to 15.3 psig using high-pressure motive steam at 200 psig.
For a compression ratio of approximately 2:1, around 11,000 lb/hr of high-pressure motive steam is required to entrain 10,000 lb/hr of low-pressure suction steam, producing approximately 21,000 lb/hr of useful intermediate-pressure process steam.
By eliminating low-pressure steam venting, the facility can recover approximately 10.7 MMBtu/hr of energy. For continuous operation, this equates to around 94,000 MMBtu per year. Based on natural gas priced at $8.00/MMBtu and boiler efficiency of 80%, the potential annual fuel saving is approximately $940,000.
In vacuum applications, steam jet ejectors use motive steam to entrain air, vapour and non-condensable gases from the process. The motive steam and suction gases pass through the mixing chamber, Venturi throat and diffuser, where the mixture is compressed and discharged at a higher pressure.
Steam jet ejectors can operate with motive steam pressures as low as 5 psig, although pressures in the range of 15 to 50 psig are generally more practical for efficient vacuum generation.
New Field Thermocompressors provides a practical, reliable and cost-effective means of recovering low-pressure steam and converting it into valuable process energy. By reducing steam losses, improving heat recovery and lowering boiler demand, they help industrial plants enhance efficiency, reduce operating costs and support more sustainable operation.
