Cider desulfurization plants in detail
- Exchange column made of glass
- Low maintenance and servicing costs
- Particularly easy to clean
- Does not impair the taste of the must
The heart of the STRASSBURGER desulfurization system, the exchange column, is made of glass due to the aggressive vapors, as are the feed line and the sprinkler, where the highest temperatures are present. The glass parts are particularly easy to clean. Other parts and lines in contact with the product are made of high-alloy chromium steel (V4A). The remaining parts are made of normal chromium steel. The glass column is hung in a pipe frame to provide stability. The patented STRASSBURGER process eliminates the need for a costly vacuum pump and the maintenance and servicing costs are low.
The purest possible lime (e.g. STRASSBURGER special lime), which is prepared in the stirring tank (included in the scope of delivery), ensures gentle desulfurization and trouble-free (residue-free) cleaning of parts that carry lime milk. About 2 kg of lime is consumed per 1,000 liters.
The steam generator and any required cooling unit are not included in the scope of delivery. The system, which is subject to 1 bar pressure during operation, does not require TÜV approval.
The sulfurized cider is pumped through the plate heat exchanger by a centrifugal pump and heated in stages. Preheating is done by counterflow of the backflowing desulfurized cider (heat recovery). The next stage of further heating to the final temperature is done by counterflow of the saturated steam.
The cider has now been heated to over 110°C and a sprinkler spreads it over a large surface area in the exchange column through ceramic rings. The sulfur dissolved in the cider turns into vapor.
The steam formed in the lime milk tank by heating flows from the bottom to the top of the column (towards the cider) and strips the released sulfuric vapors along with it.
A centrifugal pump then circulates the lime milk from the lime milk tank to the gas jet washer, which uses the injection method. The resulting “vacuum” draws in the sulfur vapors, mixes them with lime milk in the tube of the gas jet scrubber, and “washes"” (neutralizes) them as a result. The vapors, purified by this method, flow back into the column through a droplet separator.
The cider discharged below the column is now desulfurized by around 90%, depending on the cider temperature and pH (sulfur is bound more tightly when the pH level increases).
The desulfurized cider is fed into the plate heat exchanger to preheat the not-yet desulfurized incoming cider. After passing through this heat recovery compartment, the cider has now reached a temperature 5–10°C above the inlet temperature.
If the inlet temperature is already very high, the cider can be cooled down in a third compartment in the heat exchanger by water or a cooling liquid. A centrifugal pump at the outlet of the heat exchanger ensures that the cider is discharged smoothly.