Cooling of wort carried on after cooking and before fermentation in whisky production is an essential part of the process, since the working temperatures range is very tight, and at higher temperatures, it happens a reduction in the fermentation power, as well as a loss of evaporated alcohol and a reduction of the flavours.
The special process conditions, with a strong content in suspended solids (grains, stones, leaves, straw) in the fluid to be cooled, the necessity of a very exact final temperature of the wort at the outlet of the cooler, and the strict cleaning conditions after consecutive production cycles, recommend to use tubular heat exchangers instead of others, as plate heat exchanger, where the deposit of solids would make difficult the thermal transference, resulting in reduction of the production, or spiral or platular heat exchangers, which could show important mechanical problems. It is usual to consider different cooling media along the worts circulation, with the aim of achieving the required final temperature, as tower water, town water, chilled water, or glycol. This involves that the calculations of the different units composing the thermal transference train must take into account considerations as different flow rates for each cooling media, as well as its economic impact, which should be the lowest.
Moreover, economic and environmental restrictions particular of every process must be considered, and those required by the current legislation, as guarantee a determinate outlet temperature in the cooling media, which allows its later use in other areas of the installation, or ensure a right and reasonable energy consumption when coming back to the initial working conditions in the heat exchanger.
The Multitube ITMb is a welded corrugated heat exchanger. Flanged tube sheet allow you an easy and quick visual inspection. We understand that hygienic equipment has to be cleaned easily. It is preferable to have the possibility of inspecting the sanitary side, in our case, the inner tubes.
From the mechanical point of view, it is very important to consider the number of production cycles, as well as the periodicity and conditions of the cleaning cycles, and also, working pressures and any change which could appear in them during the process.
Particular metal bellows is a critical element which must absorb every differential expansions and contractions which could affect to the equipment because of pressure and/or thermal shocks, in order to avoid stress in the welds, enlarging the working life of the equipment.
Following the features of the worts, a flanged tubular-sheet must be used to allow an easy access for inspection and/or mechanical cleaning if necessary, paying special attention to the disposition of modules on the frame, since it must ensure the self-drainability of the heat exchanger, looking for recovery the most of the worts in shut down conditions, at the same time it makes easy the connections of the different sections to the pipelines of the different cooling media if any. In case of outer installation, in areas where the ambient temperature could be extremely low in some seasons, it is recommended the installation of system of valves in the shells to drain them, avoiding possible problems due to freezing of remaining fluids.