Heat exchanger is used for heating of slurry, sludge and biomass in biogas plants and in food industry. It used not only for heating but also for cooling of distillery stillage and vinasse,  musses at vinaries and beer breweries, for recuperation of heat from different effluents as well for sanitation of substrates at +70C.

The spiral heat exchanger is made out of aluminum, a non-corrosive alloy. To avoid hard alteration of the direction of the flow, the spiral channel has an anti-clockwise curvature (left-hand element) and a clockwise curvature (right-hand element). The transition from one element to the other is performed without changing the direction of the flow. Therefore, the risk of plugging by solid particles is very low. Also, a contamination of the heat exchanging surfaces by fouling is effectively avoided by using sand-blasted aluminum cast surfaces and the spiral-shaped, curved trapezium channel with a distinctive secondary flow. It guarantees a high exchange capacity. The heat exchanger can fully be dismounted and it can be checked and cleaned at any time, if required.

Thermodynamics and fluid-flow characteristics

• maximum particle size is 20 mm
• very good heat conduction by aluminum compared with steel
• aluminum - cast surface with better roughness and surface quality
• high heat transfer coefficient 500 to 2500 W/m²/K
• the surface area of the heat exchanger can vary between 1.5 m² and 15 m²
• volumetric flow capacity from 5 to 30 m³/h
• temperature to +90 °C;
• operating pressure at 4 bar
• heating/cooling capacity of the heat exchanger is available between 20 and 800 kW

Material quality

• aluminum casting aged with increased temperature that nearly has the hardness of steel
• corrosion proof and sea-water proof
• surface of aluminum casting with high resistance against organic acids in biomasses suspensions as well as anti- adhesion effects in case of fat and protein
• no cleaning of the heat exchanger walls
• temperature resistant and medium resistant sealing
• in case of problematic suspensions different surface coatings available, e.g. Teflon

Dimensions of heat exchange elements

• diameter: 980 mm
• height: 175 mm
• weight: 110 kg
• height of packages: max. 2200 mm

Environmental Acceptability

• suspensions will not be contaminated by heavy metal because of abrasive wear and the heat exchanger can be used in the food industries
• operation without plugging and maintenance for suspensions up to a percentage of solids of 15 % with correct removal of harmful substances
• cleaning is generally done only by means of water
• small space requirements because of compact construction
• recycling of worn elements is done at the foundry