Gas Conditioning

Nozzle Selection

A variety of nozzles are suitable for gas scrubbing applications. For packed bed scrubbers TF spiral nozzles can give very wide distribution patterns with up to 170 degree spray angles. TF nozzles are also useful in absorber spray scrubbers as they produce sprays with good levels of atomisation.

If fast moving gas flows need  to be overcome then large droplets may be desirable so SC or MP nozzles might be suitable as these produce large droplets with high momentum sprays.

For very small gas flows that require quick scrubbing low flow, very fine scrubber sprays will be suitable to P, PJ or L series misting nozzle might be a good choice.

GAS COOLING NOZZLES

The cooling of gas flows by injecting water or other coolants is a very common application for our spray nozzles. Correct nozzle selection is of critical importance in many spray cooling applications as the properties of the spray will determine how quickly heat is absorbed and where the spray will reach within a given gas flow.

Nozzle selection

When spraying into a hot gas flow above the boiling point of the coolant most of the cooling is caused by taking heat from the gas to evaporate the fluid. The rate of evaporation will depend on the average droplet size of the spray. Sprays consisting of smaller droplets will evaporate far more rapidly that sprays containing larger droplets. In fast moving gas flows this can be very important as often cooling needs to be achieved before the gas reaches another point in the process. Correct nozzle selection can thus reduce the need for long quench chambers.

Not just droplet size

Whilst sprays consisting of very small droplets will absorb heat faster they will also become entrained within gas flows more easily. This means that if a spray is too fine it may only cool a channel within a gas flow rather than the whole gas volume. So there is often a balancing act to be performed between getting sufficiently small droplets to achieve rapid heat transfer and have enough larger droplets to carry the spray into a gas stream and distribute it evenly.

Variable gas flows

In many applications the amount of gas that needs to be cooled can vary depending on operating conditions. For example the pre-quenching of hot flue gasses before they enter a scrubber may vary dramatically depending on what is happening further up the process line to produce the gases. Variable cooling loads present problems for spray cooling because lowering the amount of coolant spray will typically mean lowering fluid pressure which will increase the droplet size and thus increase evaporation time. This means that in lower gas flow scenarios cooling may not be achieved in time, or may necessitate a deliberately larger quench chamber.

There are a number of ways in which good nozzle selection can help overcome variable gas flow cooling problems. The use of spillback nozzle systems means that droplet size can be kept relatively stead even if the pressure and flow rate are reduced. Alternatively air atomising systems with variable air and fluid pressures can be used to maintain smaller droplets at reduced flows. Finally multi nozzles arrays can be deployed to given variable flows at stable droplet sizes.

Spray nozzles

Gas cooling nozzle selection will vary greatly depending on the application. For many cooling applications our spiral TF nozzles produce an excellent combination of small droplets mixed with some larger droplets to give penetration into rapidly moving gasses. For variable gas flows our spillback lances can provide optimum cooling even under highly changeable process loads. Our Spriral Air (SA) nozzles give a robust air atomising system suitable for use in hot gas flows that require finely atomised sprays for rapid quenching.

As gas cooling is a wide and highly varied application other nozzle types may well be recommended depending on the situation.

FLUE GAS DESULFURIZATION (FGD): OVERVIEW

BETE provides a wide variety of high-performance nozzles for all aspects of the flue gas desulfurization (FGD) process. FGD specifically targets the removal of sulfur oxides, commonly referred to as SOx, from an exhaust gas using an alkali reagent, such as a wet limestone slurry.

FGD inquiry worksheet (PDF – 87 KB)

BETE FGD Technical Manual (PDF – 1 MB)

http://www.bete.com/pdfs/BETE_FGD_Techmanual.pdf

FGD requires precise calculations and nozzle fitting to ensure continual proper functioning of the system. BETE engineers have decades of experience in helping customers around the world find the best FGD solution for their custom application.

Types of FGD Nozzles:

• FGD Absorber Nozzles
• http://www.bete.com/applications/fgd_absorb.html
• FGD Mist Eliminator Nozzles
• http://www.bete.com/applications/fgd_mist.html
• FGD Emergency Quenching Nozzles
• http://www.bete.com/applications/fgd_quench.html

Selecting a FGD Nozzle:
To learn more about which nozzle would be right for your application, please explore the specific categories listed above, or contact our experienced engineers.

Common FGD Nozzle Uses, Applications, and Industries:

• Coal and other fossil fuel power plants
• Petroleum refineries
• Municipal Waste Incinerators
• Cement kilns and metal smelters

GAS COOLING SPRAT NOZZLES

Evaporatively quench hot gases

Hot gas can be cooled to a lower temperature by evaporating a liquid into the gas stream. Smaller droplets lead to faster evaporation times and a shorter distance required for the gas temperature to reduce to the desired level.

Nozzle Selection Guidelines

A number of thermodynamic calculations need to be made to select the correct nozzle for a given situation and are based on a variety of factors. The information required to make these calculations is detailed in the BETE Gas Cooling/Quenching Application Data Sheet (PDF – 229 KB). With this information, BETE Application Engineers can perform the calculations and combine the results with their knowledge of nozzle performance and help select the nozzle that fits your needs.

Typical operating conditions for this application are listed for each nozzle

GAS QUENCHING NOZZLES

Evaporatively quench hot gases

Typical operating conditions for this application are lister for each nozzle

DELAVAN

SWIRL AIR NOZZLES

http://www.delavan.co.uk/pdfs/swirlair-brochure.pdf

PNR

http://www.spraynozzle.co.za/pdf/PNR%20EvaporativeCooling.pdf

HOLLOW CONE

FULL CONE