Desuper Heater
Product Range
Desuper Heater
Flow-Tek Desuperheater is a leading supplier of steam desuperheaters, specializing in the design and manufacture of high-performance systems for power plants, process industries, and co-generation facilities.
The most effective method of lowering steam superheat temperature is through the controlled injection of water. For maintaining stable outlet temperature and avoiding thermal stress in downstream piping, the cooling water must be finely atomized. Proper mixing between superheated steam and the injected water is essential to ensure efficient and uniform temperature reduction.
Features
- Compact, space-saving modular construction
- Eliminates the need for a separate cooling water control valve
- Produces extremely fine water atomization
- Incorporates advanced patented nozzle technology
- Easy and hassle-free installation
- Capable of operating under high differential pressure conditions
Efficient Steam Temperature Reduction
The achievable reduction in outlet superheat is primarily dependent on the performance of the control system. In most applications, desuperheaters are designed to lower steam (or gas) temperature to a level approaching its saturation point.
Most desuperheater models are capable of reducing steam temperature to the saturation point or very close to it. However, precise control is essential to avoid over-injection of water, which can lead to system flooding. The main limitation lies in the sensitivity and accuracy range of the control system. For example, consider a system set to maintain an outlet temperature 1 °C above saturation, with a control accuracy of ±1 °C. In such cases, tight regulation becomes critical to ensure stable and safe operation.
Cooling water injection continues until the steam temperature reaches the saturation point, after which the control system begins reducing the water flow. However, due to inherent control system delays—particularly those associated with derivative action, which are beyond the desuperheater manufacturer’s scope—the cooling water may continue to flow at the design rate for a short duration.During this brief period, the saturated steam can begin to condense. The condensation of vapor creates a localized vacuum, drawing in additional vapor that also condenses. This chain reaction can lead to loss of temperature control, potential damage to downstream equipment, and disruption of process operations.For these reasons, desuperheating performance is typically not guaranteed below 4–5 °C above the saturation temperature. Such a small degree of remaining superheat does not significantly impact downstream processes and ensures stable, safe system performance.
Operational Guidelines for Efficient DSH Performance
- A minimum straight pipe run of 4 meters is to be ensured at the outlet section.
- Spray water must conform to boiler feedwater quality standards.
- Steam and water pressure differential should not exceed 45 bar.
- Instrument-quality compressed air shall be available for control operation.
- The lowest achievable controlled temperature shall be Saturation Temperature + 7°C.
- Required minimum inlet steam velocities: 15 m/s for FND type 7 m/s for VND type
- The temperature sensing element shall be located 10–12 meters downstream of the water injection point.
- Steam flow conditions, both maximum and minimum, should be realistically defined.
- Unnecessarily wide turndown ratios may demand the use of multiple nozzles within a single spray cylinder assembly
- Where higher differential exists, a pressure control valve must be incorporated in the water line to regulate the pressure accordingly.
- Provision of a 0.8 mm mesh strainer upstream of the water control valve is advised to safeguard the system.
- Water supply pressure is required to be minimum 7 bar above the corresponding steam pressure.
Applications
- Steam Systems