Batch Vacuum Pan Design Specification

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Refinery White Pan

Strike Level above tube plate1300 - 1400 mm
Graining Volume % Strike Volumeless than 40 %
Graining Level above tube plate50 mm
Heating Surface to Volume ratio7.0 m-1
Down Take Diameter % Pan Diameter40 %
Disengagement space above strike level2 m

Raw A (and First Crop Recovery) Pan

Strike Level above tube plate1300 - 1400 mm
Graining Volume % Strike Volumeless than 35 %
Graining Level above tube plate50 mm
Heating Surface to Volume ratio6.0 m-1
Down Take Diameter % Pan Diameter40 %
Disengagement space above strike level2 m

Raw B and C (and Second and Third Crop Recovery) Pans

Strike Level above tube plate1300 - 1400 mm
Graining Volume % Strike Volumeless than 35 %
Graining Level above tube plate50 mm
Heating Surface to Volume ratio5.5 m-1
Down Take Diameter % Pan Diameter40 %
Disengagement space above strike level2 m

Load Conditions

The following load cases shall be considered

  1. Self weight
  2. Weight of massecuite (pan filled to the very top)
  3. Full vacuum in pan body
  4. Full vacuum in calandria
  5. Full design steam pressure in calandria
  6. Calandria full of water
  7. Full calandria pressure in the pan body

The following combinations of the above load cases shall be considered

The value of density used for massecuite shall not be less than 1500kg/m3.

Tube Plates

The tube to tube plate joint shall be by expansion. The expansion joints shall comply with the following requirements

Tube specification

The tubes shall comply the sugartech specification for tubes less than three metres in length. Furthermore, the tubes shall be supplied in the annealed condition. The finished tube shall not have a weld bead either on the outside or the inside. The tube nominal diameter shall be 4 inches (101.6 mm), the tube wall thickness shall be 1.5mm.

Sight and Light Glasses

The sight glasses shall be arranged vertically with the centre of the second sight glass from the top at the design strike level. One light glass with and electric light fitting shall be located at the rear of the pan. Wash water sprays shall be provided to all light and sight glasses. The transparent material shall be Lexan or similar product, sufficiently strong to resist all load conditions.

Man-ways

Man-ways shall be of sufficient size so that the stirrer blades and the entrainment packs can be fitted and removed. No man-way shall be less than 450 mm in diameter.

Feed Manifold

The distribution of liquor to the pan shall be by means of an external ring line from which risers lead to radial distributors. The feed velocity shall not exceed 1 m/s 5.16 Calibrated level board A calibrated level board marked in metres and centimetres shall be provided adjacent to the sight glasses. The level board shall indicate height above the top of the top tube plate.

Pan Stirrer

The pan stirrer shall comply with the sugartech specification