C.A.V.T. (Cold Air Velocity Test)

    C.A.V.T. is to predict the flow profile of flue gas by manually measuring the velocity of cold air inside the boiler at pre defined locations( Second pass of boiler).

C.A.V.T. is performed twice:

• Before installation of erosion control devices.

• After installation of erosion control devices.

     Generally when flue gases pass through second pass  of boiler, because of resistance offered by the tube bundles , the flow tends to take place through the gap between boiler casing and boiler coils. As the area of this region is very small compared to total flow area, velocity in this region increases. Due to combined effect of high velocity and impingement angle of ash particles the tubes in this region get eroded. To pin point such problem areas the second pass of boiler is divided in to number of planes, and velocity of cold air is measured on pre defined points on each of these planes. This data is used to design the erosion control devices which help to minimize the erosion of boiler tubes. Commonly, E.M.S. (expanded metal screens) are used as E.C.D.

     With the help of carefully designed E.M.S., resistance is introduced in the gaps to reduce velocity in the problem area. The E.M.S. not only add resistance to flow through gap but also take the erosion and protect the boiler tubes from erosion. E.M.S.s are easily repairable and replaceable.

Gas velocity test:

     To ensure equi distriburtion in various ducts, velocity and flow is measured in each duct. Diverter plates with designed shapes are provided in duct at corrected prices to ensure equi distributions.

Gas distribution test:

     Velocity measurement is carried out by animometer by forming the grid between first and second field of ESP. The distribution is made uniform across the cross section of ESP by

  • Installing honey comb
  • Guide veins in duct
  • Modifying the GD screens
  • By adjusting the diverters at screen.
  • Stack emission test:

         This test is done to find out ash burden at ESP outlet.

    Thickness survey:

         To predict the residual life of boiler tubes at various locations.

    Air leakage test:

         O2 measurement is carried out at inlet and outlet of duct. O2 percentage will increase if there is air ingres. To pinpoint the air ingres locations surface temperature measurements will reveal the ingres prints.

    Noise Acquisition

    Noise Data Acquisition:

         After collecting data from field it is used for further post processing with the help of computer added instrumentation. The raw data’s can be converted and presented according to user defined way including SPL Vs time, SPL Vs frequency and utilizing Octave bands filters. The same is also used for validation with aero acoustics CFD results.

    Acoustics Solutions