Comparison of designs and economic efficiencies of air circulation systems in dryers (Part 1)

In remembrance of Dr.-Ing. Karsten Junge

»1 Drying times of various drying methods

»2 Specific heat requirement (specific to the expelled water) of chamber and continuous dryers as a function of drying time (7 roof tile factories in Germany)

$»3 Drying time as a function of core-hole fraction in 1 RF (traditional) bricks for otherwise unaltered raw materials (channel dryer in Russia)$

»3 Drying time as a function of core-hole fraction in 1 RF (traditional) bricks for otherwise unaltered raw materials (channel dryer in Russia)

»4 Stillage trolley with backing bricks

»5 Rotary fan dryer with rack

»6 Airwall dryer with frame

»7 Slats and clinkers

»8 Oversize pallet

»9 Carrier with interlocking tile

»10 Stackable carriers on platform car

»11 Carrier with QuickPoint support

»12 Saturation of drying air in passage over several bricks in a row

»13 Relative drying rate as a function of relative length of flow channel acc. to [13] and own investigations

»14 Comparison of drying curves for a flat clay roofing tile (8.6 pcs/m²) in rapid and conventional drying processes

»15 Rotary fan dryer drive with inlet nozzle, cross pole and fan wheel

»16 Cross section of a rotary fan dryer with rack and sub-ceiling hot-air duct

»17 Cross section of an airwall dryer with dryer cars and railbound airwalls

»18 Highly insulative 12 DF vertically perforated brick with 35 core rows

»19 Design and air conduction of an XStream rapid dryer for solid bricks (red = hot air, blue = moist air)

»20 Cross section of an XStream rapid dryer for masonry bricks and clinkers, with stillage trolley (continuous dryer with supply and return setup)

»21 XStream rapid dryer for large-format vertically perforated bricks (mobile see-through partition)

»22 XStream rapid dryer for small masonry bricks or clinkers

In a convection dryer, such best-achievable economic indicators as heat and power consumption and the requisite installation space depend on the quality of the air circulation system. In German speaking areas, the two most frequently encountered types of air circulation systems for conventional dryers are rotary fans and airwalls. At the same time, more and more rapid drying processes are becoming established. The present contribution compares and analyses the measured economic operating data of the various air circulation systems. This first part deals primarily with data pertinent to masonry bricks and clinkers, while Part 2 (coming up in Zi6/2011) will present corresponding data for roof tiles. In nearly all regards, rapid dryers emerge as the most economical variant, often by a wide margin.

1 Introduction

All kinds of bricks and tiles (clay masonry units) are still being dried by means of air circulation in convection dryers. Thus, the air circulation system constitutes the dryer‘s core component, much like the engine of an automobile. That being so, the best-achievable economic indicators – in terms of heat and power consumption or requisite installation space [1, 8, 9, 11, 13, 14] – that a given dryer can achieve depend on how effective the air is being circulated.

All over the world, bricks of all shapes and sizes are being made of widely disparate clay raw materials [10, 29]....

Comparison of designs and economic efficiencies of air circulation systems in dryers (Part 1)

1 Introduction

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1 Introduction

ZI 5/2011

ZI 5/2011

Related articles:

In remembrance of Dr.-Ing. Karsten Junge Comparison of designs and economic efficiencies of air circulation systems in dryers (Part 2)

Rapid roller dryers from Capaccioli

Experience with low-energy drying of backing bricks

Tecton introduces state-of-art technologies at new Leier brick works in Petrovany, Slovakia

Industrial dryer technology: optimized air circulation