News

Comparison of Performance of the New RL-3 Impeller to the HE-3 Impeller

Chemineer have produced a comparison of the HE-3 up-pumping impeller and the RL-3 down-pumping impeller. Both are installed at the Plant at Pinellas County Florida, South Cross Bayou WRF.  

  RL- 3 Initial Installation

 

HE-3 Initial Installation 

 

 

 

 

 HE-3 After 8 Weeks Operation                        RL-3 After 8 Weeks Operation

 

 

 

 

 

For further information please contact us

 

RL-3 Ragless TM Impeller

Chemineer has announced the addition of a new impeller to their product line. The RL-3 Ragless TM impeller is engineered to prevent fibrous material build up by eliminating any sharp edges or protrusions on the impeller blade. Build up of materials can impact on the performance thus increasing energy costs and may damage the agitator, bearings and gearbox. The new design prevents build up therefore eliminating maintenance costs and downtime to clean the impeller and extending the service life of the agitator.

17MR and 18MR

The expansion of the RM Agitators line now includes sizes 17 and 18. These two new sizes complement the Legacy HT units whilst providing Chemineer quality in lighter duty / less demanding applications such as ethanol, mining, water and waste treatment and storage tanks. The MR is available in open top beam mounts and sealed closed top configurations.

Choosing the correct type of mixer for your liquid phase chemical reaction process

Agitators and static mixers are both commonly used in chemical reaction processes. They have quite
different characteristics and the correct choice is vital to an efficient, successful, optimised and low energy
consuming process.

Agitated systems can benefit from the use of expert design software and CFD simulation as well as the use of
high efficiency impellers to minimise energy consumption and reduce batch mixing times to achieve specific
targeted objectives.
 
Images below show multistage agitated cascade reaction vessels and a 3D CFD image modelling flow patterns
in a gas liquid reactor.

 

Static mixer reaction systems can be employed in many traditionally batch processes. Static mixer
reactors offer benefits in both capital cost, plant size and reaction selectivity. Image below
shows a typical skid mounted continuous static mixer reactor system.
 

 

 

 First consider the chemistry and the process objectives and decide on the best available technology 

   

Process Objective

Mixer type

 
 

Best technology

Second best technology

Mixing for instantaneous reactions

Static mixer

Agitator

Reaction, reaction times
1-2 seconds to 2-3 minutes

Static mixer

Agitator

Reaction, reaction times
> 3 minutes

Agitator

Static mixer

Competing, consecutive
reactions

Static mixer

Agitator

Non competing reactions.
Gas – liquid reactions.

Either technology can be used successfully, sometime both together for even better results.

 

Liquid solid reactions

Agitator

Static mixer

   

Choose the correct type of static mixer dependent on the flow regime:

 

Flow regime

Mixer type

Image

Laminar
(Reynolds<100)

KMX (structured) or
KM (helical)

 

Transitional
(Reynolds 100-5000)

KM (helical)

 

Turbulent
(Reynolds >5000)

HEV Vortex inducing) or
KM (helical)

Selection of the correct type of static mixer can reduce energy consumption by 3-4 times for the same quality
of mixing (CoV or Coefficient of Variation).
   

Selection of the correct type of static mixer can reduce energy consumption by 3-4 times for the same quality
of mixing (CoV or Coefficient of Variation).

Choose the correct type of agitator impeller dependent on the flow regime:

 

Flow regime     

Impeller type

Image

Laminar

Helix, anchor

               

Transitional

HE-3, MW4, 4P

                        

Turbulent

HE-3, SC-3, MW4

  

Selecting the correct type of impeller for the duty and optimising the impeller diameter and speed can
potentially reduce energy consumption by up to 10 times for the same blend time.

Summary:

  • Select the correct technology for the process objectives.
  • Allow your supplier to select the correct type of static mixer for the process. Don’t assume that all
    static mixers are the same.
  • Allow your supplier to select the correct type of agitator impeller, speed and diameter to minimise
    blend time and energy consumption. Don’t impose agitator specifications without expert advice.