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Experience Exchange is the space for sharing your industry stories , from cautionary tales to enlightening experiences .
Surprise innovation : 50 days ’ work done within 1 hour
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By Osama Nasser , CEO VAU Thermotech GmbH & Co . KG
In the 1990s , I was employed as senior executive by a well-known supplier for power , chemical and industrial plants . Thanks to our contacts in the industry , we got the order to retrofit the fifth effect of an evaporation station in a sugar factory which used Robert evaporators for sugar juice thickening . The challenges of this job were a limited footprint , using the existing piping peripherals , and enhancing the evaporation capacity by enlarging the heating surface . Therefore , we decided to use the hybrid tubular plate heat exchangers my father invented 20 years ago as the heating surface for the new falling film evaporator . To avoid formation of deposits like sugar coal , that may plug tubes and cause system failure , it is crucial that the sugar juice is guided through the process with an appropriate juice distribution within a certain residence time and within a precisely defined temperature interval . To achieve this goal , more effects are used in a sugar factory . Also , the juice distribution system on the top of the vessel is important to ensure a very even flow of the sugar juice . Upfront , a lot of research was done by engineers and scientists carefully calculating almost everything . So , the juice distribution system of our vessel consisted of an inlet pipe that fed the juice onto a perforated plate with 52 rows of 99 holes each with a diameter of 2 millimeters . After the hybrid tubular falling film evaporator had been mounted successfully , a test run of the system was started . Suddenly , at 10 pm an unpleasant surprise : the thick juice accumulated at the top of the vessel and the system was blocked . The cause was that in the fifth effect of the evaporation station the sugar juice had already thickened and was very viscous . This led to a high surface tension of the thick sugar juice which prevented its free flow through the 2-millimeter holes of the perforated plate . Since the evaporation station is the heart of every sugar factory , the whole plant was at a standstill caused just by a single perforated plate . So , good advice was hard to come by , even late at night and in-between the sugar campaign where thousands of sugar beets awaited processing . The initial idea was to enlarge the diameter of all holes in the perforated plate by drilling them . But 99 holes in 52 rows equals 5,148 holes to drill , and every hole needs one to five minutes to drill ; in total , it would take 10 to 50 days to complete this operation . That was clearly much too long ! Finally , I asked for an angle grinder , which definitely confused the sugar factory engineers . I made sure that 5 millimeter cuts were made into the perforated plate connecting three holes in a row and leaving small ligaments between the slits to ensure the stability of the plate . Within an hour this work was done , and the sugar juice flowed unobstructed . Over the next 10 years , this juice distribution system remained unchanged in operation . In the end , we adopted this design , and it has built the basis of our today ' s juice distribution systems .
About the Company
The owner-managed VAU Thermotech GmbH & Co . KG was founded in 1977 . Owner and CEO is Osama Nasser . Headquarters and production are located in Heldrungen , Germany . The company manufactures brazed plate , fully welded hybrid tubular and gasketed plate heat exchangers . Design and production are all “ Made in Germany ”.
Original pictures of distribution system at that time www . heat-exchanger-world . com Heat Exchanger World September 2022
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