Pasteurizing Honey17 January 2018
Honey is a natural liquid sweet substance that arises when honeybees collect nectar from flowers and then convert them. The nectar is converted into honey by adding enzymes as well as thickening by evaporation. Honey is used by humans as a food. The color and taste of honey is largely determined by the origin of the nectar (honey from the dandelion tastes different from that of, for example, the lime), but also the degree of crystallisation influences the taste sensation.
Spiralex BV has supplied the Spiralex® corrugated tubular heat exchangers for a honey producer for the pasteurisation of honey. The difficulty of heat transfer lies in 2 properties of the honey, namely:
- Viscosity of the honey; this determines the flow regime in the heat exchanger;
- Crystallization of the honey; this determines the residence time of the honey in the heat exchanger.
In this case, Spiralex BV has assessed the above values. Unfortunately, the honey producer did not know what the properties of his honey were; partly because he receives the honey from various suppliers (beekeepers).
The assignment was to treat the honey as follows:
- Heating 2,000 kg/hr of Honey from 45 °C to 72 °C; We have chosen a Spiralex® corrugated multitube heat exchanger with a length of 6 meters. We chose 2 pieces.
- Cooling 2,000 kg/hr of Honey from 72 °C to 40 °C; We have chosen a Spiralex® corrugated tripletube heat exchanger (or annular space) of 6 meters in length. We chose 3 pieces.
During the construction of the complete system, the end user decided to expand the cooler. He wanted to cool the Honey to 35 ºC instead of 40ºC. We supplied 2 extra units in the cooler to realize this.
During the start-up and test runs, it turned out that the starting points of the honey were not correct:
- The cooling was perfect: with the 5 corrugated tripletube heat exchanger we cooled the Honey from 72 ºC to 35 °C. The total capacity of these units is 42 kW.
- The heating did not reached the desired temperature of 72ºC. We decided to extend the heating section to 5 units as well. This allowed the customer to heat up to an even higher temperature in the future . In this way the heating section could transfer 35 kW to the honey.