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NEW exhaust steam condensing system for steam peelers Zero emissions and energy savings; the new Steam Peeler E-Condenser offers numerous economic benefits. Anyone who follows the developments in the potato and vegetable processing industry will readily acknowledge that increasingly higher demands are being placed upon equipment. Not only in a technical sense, but also from the viewpoint of the environment, more and more is demanded. Efficient use of energy and zero emission operation are important goals in this industry. Goals that are realized in Royal GMF-Gouda's latest development…the Steam Peeler E-condenser. This exhaust steam condensing system combines energy savings and zero emissions operation into a mechanical system with strong economic and environmental benefits. The first E-condenser will soon be put into service at a branch of a major Dutch chips producer in Germany. The E-Condenser (patent pending) is a development that arose in close cooperation with Solutherm. Solutherm is an engineering bureau that is primarily engaged in thermal process optimization in the food industry. During development, every effort was made to account for the widest possible range of applications. The E-condenser can therefore not only be used in conjunction with the steam peelers of Royal GMF-Gouda, but also with those of other manufacturers. The E-condenser is easily accessible for inspection and cleaning and has a relatively compact design, making its integration possible in practically any existing plant environment.  Peeling lines for potatoes and vegetables Hundreds of steam peelers of Royal GMF-Gouda are in use worldwide. The steam peelers are part of peeling lines where potatoes and vegetables are stripped of their peel in a batch-wise fashion. Products are loaded into the steam peeler and saturated steam, with a pressure of approximately 16 bar, pressurizes the closed steam peeler. The condensation heat of the steam raises the temperature of the moisture within, and just underneath, the product's outer cell structure to above 100 °C. After just a few short seconds of pressurized processing time, the pressure within the peeling vessel is quickly released, the moisture in and under the peel begins to boil (flashing and turning into steam, itself), causing the peel to come off the product. Until now, the steam released from the peeling vessel was blown off to the outside atmosphere, via a steam expansion tank. This not only results in a great loss of energy, but also causes noise and odor emissions. Both of these results are potentially annoying to nearby residents. The E-condenser changes that. Utilisation of thermal energy The E-condenser is an extension of the peeling line, having a physical size not larger than a typical steam expansion tank. The steam expansion tank functions as a cyclone, where any contaminants transported from the steam peeler are separated from the escaping vapors. The compact design makes it possible to place the condenser directly beside the existing steam expansion tank, which has been improved on a number of points at the same time as the introduction of the E-condenser. The E-condenser consists of a tank with a diameter of approximately 2400 mm, containing a cassette with stainless steel plates. The plates have a thickness of approximately 1.5 mm, each separated by a distance of approximately 1 cm, allowing for the free passage of steam. At the top of the tank, there are sprinklers that continuously spray relatively cold water over the stainless steel plates. When the exhaust steam from the steam expansion tank is blown into the bottom side of the E-condenser, it condenses on the relatively cold surface of the plates. This heats up the stainless steel plates. These plates then transfer the stored heat to the water, bringing the water temperature to approximately 80 °C. This heated water can be used for various purposes, such as the pre-boiling of products, or the pre-heating of boiler water. Of course, this heated water could also be buffered and used for cleaning purposes. Zero emission operation The E-condenser is designed as a closed system, whereby all energy of the blown-off steam is retained. In order to guarantee a zero emission operation, the exhaust condensation process is vacuum designed. A vacuum pump creates an underpressure of 600 mbar (absolute). The remaining non-condensed vapour is removed via the vacuum pump. With this residual heat, cold water is pre-heated via a plate heat exchanger, also part of the E-condenser. Substantial savings Recently, a start was made with the construction of the first E-condenser for the German branch of a Dutch chips producer. For this factory, located near a residential area, the zero emission operation was an important argument to expand the steam peeling line with an E-condenser. Moreover, the system ensured for substantial energy savings. As much as 65% of the energy that is supplied to the steam peeler can be recovered with the exhaust condensation system. The payback time, which lies on average between 1 and 3 years, amounts to approximately 1.3 years at this chips producer. The E-condenser fits nicely into the goals of the national governments and the European Union to realize a reduction in energy consumption of 20% by year 2020. The potato and vegetable processing industry must contribute to this goal. The Dutch potato processors aim for an energy saving of 30% within the coming 20 years. The E-condenser will help attain this goal. The amount of residual heat that can be recovered with the exhaust condensation system varies from 300 to 700 kW per steam peeler, depending on the size of the peeling tank, steam pressure, size of the product and steam exposure time. As a direct result of utilizing the E-condenser, the annual savings of natural gas will vary from 250,000 to 500,000 m3 per steam peeler (based on 7000 operating hours per year). |