Apparatebau GmbH

TECHNICAL INFORMATION CSL 2013

CALDYN Nozzles Type CSL

Analysis of droplet velocitydistribution

Principle

Nozzle CSL was developed byCALDYN and has been proven asa very robust and economicalspraying technology over the pastyears. Liquid and gas are mixedat low velocities in a mixing chamberand accelerated to the sonic velocityof the two phase mixture. Theatomisation is achieved by thepressure jump at the outlet of thenozzle when the mixture is expandedin a gas atmosphere (see Fig.).

Characteristics

CALDYN nozzles CSL generate adefined and narrow droplet sizedistribution. A variation of the jetthrow and the droplet size distributioncan be achieved by changing theliquid flow rate and the gas pressure.The liquid flow rate can be regulatedfrom zero to maximum design flowrates.The angle of atomisation for a singleCSL nozzle is equal to 15°. Thereforethe atomisation of liquids can berealised in very small channels.For larger flow cross sections, anumber of small diameter nozzlesor a multiple cluster nozzle with alarger angle of atomisation can beused (see type overview).For most applications of atomisationsystems in the process technologythe characteristics of the spray mustbe known exactly. Beside thetheoretical research CALDYN tookextensive measurements of thedroplet size and velocity distributionswith a phase doppler particleanalyzer (see Fig.).

Droplet size- and droplet velocitydistribution measured with PDPA

Transmitter of thePDPA system

Listing of PDPA-measurement

Due to the working principleCALDYN nozzles CSL have acomparatively large outlet diameterand operate with low flow velocities.Therefore liquid with solid contents(e.g. lime or slurry) as well asviscous liquids can be handledsuccessfully.For many applications of atomisingsystems it is important to know thejet velocity profile beside the dropletsize distribution. With the CALDYNdimensioning software the jetvelocity profiles can be calculatedfor different operating conditions(see Fig.).

Working principle of the CALDYNnozzle CSL

The sonic velocity in a gas/liquidmixture is substantially lower thanthe sonic velocity in the gas or inthe liquid phase (Fig. 2). Thereforethe frictional and the accelerationpressure drops in the nozzle CSLhave very low values. The pressurejump at the nozzle outlet requiredfor the atomisation is achieved withvery low energy consumption. Asthe sonic velocity in a gas/liquidmixture remains almost constantover a wide range of the void fraction(see Fig.), the nozzle CSL canhandle highly fluctuating flow rateswith success.

Sonic velocity in an air/water mixture

Software for the design of CALDYNnozzles CSL

Regulation

The minimum gas pressurerecommended for operating thenozzle is 2.2 bar (g).As a result of the internal mixingof liquid and gas, the gas and liquidpressures are equal at the mixingchamber of the nozzle CSL.The liquid flow rate can be adjustedwith the help of a regulating valve(manual-operated, pneumatic-operated or motor-operated). Dueto the pressure drop over theregulating valve the liquid pressuremust be approximately 0.5 bar higherthan the gas pressure at the nozzle.The gas pressure at the nozzle iskept constant with the help of aself-actuated pressure regulatingvalve (see Fig.). The gas flow rateis adjusted automatically dependenton the liquid flow rate. As a resultof the internal mixing the gas flowrate increases for diminishing liquidflow rates (large cross section for

Operational instructions

Single nozzles and atomising lanceswith only one nozzle tip (type CSL_A,CSL_C, CSL_DE and CSL_DEKaccording to the following typeoverview) can be mounted in ahorizontal, vertical or any otherposition. The mounting position ofatomising lances with several nozzletips can be restricted dependingon the type of lance.Due to the mixing of gas and liquidin the nozzle we recommend theinstallation of a check valve at thegas connection (see Fig.). Thereforeliquid cannot enter the gas line incase of interruption of the gasflow.At start-up the gas line must beopened first. After gas pressurehas increased to the constantdesign value the liquid flow canbe regulated.At shut down the liquid line mustbe closed first. The gas line mustremain open for about 10-30 secin order to atomise the residualliquid in the nozzle. Afterwardsthe gas line should be closed.

Calculated jet velocity profile of aCALDYN nozzle CSL

the gas phase in the nozzle atlower liquid flow rates).In order to avoid the higher gasconsumption at part load conditions,a self-operated flow controller canbe mounted after the pressureregulating valve (see Fig.). Thisvalve keeps the gas flow rateconstant by varying the gas pressureat the nozzle irrespective of theliquid flow rate.The liquid flow rate can be regulatedfrom zero to maximum design flowrates. When using a flow controllera minimum gas pressure of 3 bar (g)is required.To achieve optimal results with thenozzle CSL, the liquid line shouldbe designed for a liquid flow velocityof 1-3 m/s at maximal design flowrate. The liquid line should bemounted ascending to the nozzlein order to avoid pulsations due tothe inclusion of air bubbles in theliquid line.The gas line should be dimensionedfor a flow velocity in the range of10-20 m/s.

Regulation of a CALDYN-nozzle type CSL

Type : CSL_ACharacteristic : Single nozzleConnections: § Female thread (DIN ISO 228)Applications : Atomisation of liquids in

laboratory, mixers etc.Material : 1.4571, Alloy C22, 1.4841, 1.4828,

PP, PVDF, PTFE, other materials on request

Type : CSL_CCharacteristic : Single nozzle with preliminary mixing

chamberConnections: § Thread (ISO or NPT)§ Tube (cutting ring connection)

Mounting: § Clamping ring connection (moveable)§ Flange (DIN or ANSI)

Applications : Atomisation of liquids in apparatuswith small built-in diameter and/or long built-inlength. The built-in length of the nozzle can bereadjusted by using a moveable clamping ringconnection (see Fig.).Atomisation of ammonium hydroxide or ureasolution in SNCR-plants.

Material : 1.4571, Alloy 600, Alloy C22, othermaterials on request

Type : CSL_DECharacteristic : Atomising lance with one replaceable

nozzle tip. Spray direction in the lance axialdirection or inclined to the lance axis with anangle.

Connections: § Thread (ISO or NPT)§ Tube (cutting ring connection)§ Flange (DIN or ANSI)

Mounting: § Flange (DIN or ANSI)Special design: § Protective tube with flushing air connection§ Shifting device for variable built-in length§ Water cooled design§ Nozzle tip in sintered metal for the atomisation

of erosive liquidsApplications : Atomisation of ammonium hydroxide

or urea solution in SCR-plants, quenching, sprayabsorber, aerosolenlargement, humidification ofair

Material : 1.4571, 1.4841, 1.4828, Alloy 600,Alloy C22

Type : CSL_DEKCharacteristic : Plastic atomising lance with one

replaceable nozzle tip. Spray direction in thelance axial direction or perpendicular to the lanceaxis.

Connections:§ Lapped flange (PP with steel reinforcement).

Short stub end in PP or PVDFMounting: § Flange (DIN)Special design: § Nozzle tip in PTFEApplications : Atomisation of liquids in scrubbing

systems, aerosolenlargement, humidification of airMaterial : PP, PVDF

Type : CSL_DMRCharacteristic :Atomising lance with several replaceable

nozzle tips. Spray direction inclined to the lanceaxis with an angle.

Connections: § Thread (ISO or NPT)§ Flange (DIN or ANSI)

Mounting: § Flange (DIN or ANSI)§ Special design flange (e.g. rectangular flange)

Special design: § Shifting device for variable built-in length§ Protective tube with flushing air connection§ Water cooled design

Applications : Atomisation of ammonium hydroxideor urea solution in SCR-plants, quenching,scrubbing systems, aerosolenlargement,humidification of air

Material : 1.4571, 1.4841, 1.4828, Alloy 600,Alloy C22

Type : CSL_DMRKCharacteristic : Plastic atomising lance with several

replaceable nozzle tips. Spray directionperpendicular to the lance axis.

Connections:§ Lapped flange (PP with steel reinforcement).

Short stub end in PP or PVDFMounting: § Flange (DIN)Special design: § Nozzle tip in PTFEApplications : Atomisation of liquids in scrubbing

systems, aerosolenlargement, humidification ofair

Material : PP, PVDF

Type : CSL_DMLCharacteristic :Atomising lance with several replaceable

nozzle tips in line. Spray direction perpendicularto the lance axis.

Connections: § Thread (ISO or NPT)§ Flange (DIN or ANSI)

Mounting: § Flange (DIN or ANSI)§ Special design flange (e.g. rectangular flange)

Special design: § Shifting device for variable built-in length§ Water cooled design

Applications : Atomisation of ammonium hydroxideor urea solution in SCR and SNCR- plants,quenching, scrubbing systems, aerosol-enlargement, humidification of air

Material : 1.4571, Alloy C22, other materials onrequest

Type : CSL_DMLKCharacteristic : Plastic atomising lance with several

replaceable nozzle tips in line. Spray directionperpendicular to the lance axis.

Connections:§ Lapped flange (PP with steel reinforcement).

Short stub end in PP or PVDFMounting: § Flange (DIN)Special design: § Nozzle tip in PTFEApplications : Atomisation of liquids in scrubbing

systems, aerosolenlargement, humidification ofair

Material : PP, PVDF

Main advantages of the CALDYN nozzles CSL

§ Low energy consumption § Atomisation of liquids with solid contents possible§ Narrow droplet size distribution (e.g. lime or slurry)§ Wide range of regulation § Atomisation of viscous liquids possible§ Using of steam instead of gas possible § Long wearing and plugging-free nozzles

Scope of supply

CALDYN scope of consultancy and supply ranges from the delivery of single standard nozzles, atomising systemswith special design on customer request, engineering for applications of atomising systems (such as quenching, spraydrying, scrubbing etc.) up to the delivery of complete plants. Detailed technical information is available for severalapplications upon request.

ReferencesCALDYN has delivered nozzles and atomising systems to the following companies:

Grashofstraße 12, D-76275 EttlingenTel. ++49-7243/5403-0 / Fax ++49-7243/5403-99

E-mail: info@CALDYN.de / Internet: http://www.CALDYN.de

Apparatebau GmbH