Multi-belt dryer at Langa, Westman Islands (Iceland)

Dried spines. Photo Víkingur Smárason

A multi-belt dryer has started operation at Langa in the Westman Islands, that has been designed and engineered by Dexta orkutæknilausnir ehf.

A contract about the design was signed at end of October 2013 and the dryer and it´s related equipment was tested and started on the 14th of November (2014).

Construction and assembly of the dryer, installation of related machinery and piping was performed by local companies in the Westman Islands, i.e. Skipalyftan, Eyjablikk and Vélsmiðjan Þór.

All electrical and control equipment was supplied by the local company Loftræsti- og kæliþjónustan.

Engineering of electricity, controls and programming of PLC and SCADA was done by Optech.

The dryer has five conveyor belts, each with effective width of 2,7m and effective length of each is 19m.  The belts are made of plastic and with plastic rods from Scanver (Scanbelt).

The belts are kept under tension with pneumatic actuators and the first belt has water cleaning system, on inside and outside of the belt to avoid accumulation of dirt.

The dryer is designed to pre-dry about 24 tons per day (of wet product every 24 hours) of white fish spine, whole blue whiting or similar raw material.

The dryer can both run in so-called closed system (with heat pump) or open system, thus the dryer can both dry the product by running a heat pump (chiller) or use geothermal / hot water.

Air changes are adjustable, step-less from 0-100% (of the air flow through the dryer).

The heat pump (chiller) driving the drying process by dehumidifying the air (by condensation) has cooling capacity of 960 kW and uses about 270 kW of electricity.  The heat from the heat pump is thus about 1.230 kW (COP_H = 4,55).

In addition there are cross-flow recuperators in the air flow of the dryer itself, recovering about 360 kW, thus the total heat transfer in the dryer is up to (960+360=) 1.320 kW (COP_C = 4,89).

Excess heat will be recovered to preheat outside air to after-drying, instead of being rejected.  This heat is equivalent to 250...350 kW in general.  Thus the total produced and recovered heat is thus in the range of 1.570...1.670 kW.  All together will this make the efficiency of the heat pump and the recuperators to be equivalent to COP_H = 5,81...6,19.

Dexta congratulates Langa on this occasion !