Multiple Cassette Preheater (MCP Preheater)

The new FLSmidth Multiple Cassette Preheater (MCP™ Preheater) patented design is the next generation of stone preheaters from FLSmidth

  • MCP Preheater
  • Features & Benefits

Preheater Operation

In response to industry pressure for improved capitol costs and better performance, FLSmidth has developed the MCP™ Preheater to provide a truly novel design delivering the best of both annular shaft preheaters and individual chimney preheaters.

In the MCP™ Preheater, hot gases leaving the kiln are drawn around the full circumference at cassette level. Gas enters the cassette from all sides equally due to the unique MCP™ Preheater geometry. From here the gas is drawn up through the descending stone. The gas exits the stone bed and moves through a dedicated aspirator.

In the MCP™ Preheater, each ram defines a distinct cassette, or chimney, for solids and gas to interact. Unlike the FCP, the MCP™ Preheater’s cassettes are symmetrical and constructed from a refractory lined cylinder – rather than refractory walls & columns. Also the cassettes penetrate the flat roof offset from the back wall and adjacent cassettes. This creates a full circumference for hot kiln gasses to enter the cassette, ensuring uniform gas distribution.

The stone bin is separate from the preheating area, necessitating stone to flow through chutes to the preheating zone. These stone chutes serve as restrictions to help reduce stone bin false air. Upon a ram stroke, stone moves from stone bin periphery to a stone chute. From here the stone is directed to and discharged to the preheating zone. Stone is delivered to the cassette on the centerline to help with uniform stone distribution. Stone moves counter-current to hot kiln gasses effecting preheating and precalcining. When stone reaches the cassette bottom, it spills out at its angle of repose into adjacent ram stone piles, the back wall, and feed apron. This configuration establishes a free gas path to the full cassette circumference. Upon reaching the ram level, hot precalcined stone is pushed out the fully annular stone discharge opening and onto the feed apron. From here it is pushed into the kiln.

The FLSmidth MCP™ preheater represents the next generation of pebble lime preheaters. It has proven itself to be the most trouble-free and efficient preheater available to industry. It is unparalleled in simplicity of design and flexibility.

  • The FLSmidth MCP™ stone bed can be adjusted while running. This feature serves two purposes – 1) to tune individual cassettes accounting for stone segregation in the feed bin and 2) to allow operation with multiple stone size distributions while easily maintaining optimum fuel efficiency.
  • The patented reverse distributor moves coarse stone to the cassette center reversing the classic stone pile distribution of fines-center / coarse-periphery. This feature forces uniform gas flow across the entire cassette cross-section promoting heat transfer to the entire stone size distribution.
  • Fully circumferential gas path available to the kiln offgas. This patented element completes the absolute MCP™ preheater’s symmetry ensuring equal heat transfer and low pressure drop.
  • Smaller shelf to roof dimension is required. With the FLSmidth MCP™ patented shelf geometry, there is no dead zone and material is not allowed to stagnate because the shelf is continuously cleaned.
  • Greatly reduced hydraulic pressure and less stone crushing – resulting in reduce wear on the hydraulic components and less fines generation.


Multiple Cassette Preheater Brochure
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