Safe control of low temperatures. GB 0 pages

HTT407-0820_Cryotemp_GB table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:11.00pt "Arial", sans-serif; } .font1 { font:6.00pt "Trebuchet MS", sans-serif; } .font2 { font:7.00pt "Trebuchet MS", sans-serif; } .font3 { font:8.00pt "Trebuchet MS", sans-serif; } .font4 { font:9.00pt "Trebuchet MS", sans-serif; } .font5 { font:14.00pt "Trebuchet MS", sans-serif; } .font6 { font:15.00pt "Trebuchet MS", sans-serif; } .font7 { font:28.00pt "Trebuchet MS", sans-serif; } :® = =__® energy Systems energy Systems Safe control of low temperatures Reactor temperature control down to -120° C with -plants nitrogen according to pressure, the danger exists that the heat transfer medium will solidify either partially or entirely in the heat exchanger. Firstly, heat transfer and therefore output of the unit is reduced drastically. Secondly, failure of the entire system results, as the media flow comes to a standstill. The greatest care in design in terms of heat transfer technology and operating experience with such plants is therefore extremely important in order to ensure continuously safe functioning of the entire system. Moreover, the design and construction of extremely low temperature heating-cooling-chilling plants have the following pre-requisites. Let us mention merely the following key points: ͕ Material selection according to AD-W10 for pumps, valves, devices, piping and fittings.  Knowledge and authorisations for suitable welding proխcedures.  Low temperature insulation that must simultaneously be suitable for high temperatures. Conclusion The new designs presented for extremely low reactor temperature control pave the way for the production of new types of products, which were previously inconceivable in this form and purity. In addition, CRYOTEMP® plants can improve the safety of existing production processes, since physical limits imposed up to now as a result of smaller temperature differences and the associated limitations on output can be eliminated. Different customer designed solutions can be selected according to the field of application. In spite of all these extremely interesting advantages of such plants, it should not be forgotten that by no means considerable detailed technical knowledge is required for the reliable and safe handover of such systems into the daily production operation. Dual reactor temperature control via CRYOTEMP®-plants in combination with direct N2 cooling. The restriction of the temperature range by the respective heat transfer medium already mentioned above can be remedied partially by the so-called dual reactor temperature control. Dual reactor temperature control represents a combination of a low temperature CRYOTEMP®-plant already described in detail and a special reactor cooled with two media. This type of reactor specifically developed for extremely low temperature applicatiխons has two half pipe coils in the jacket. The hcc heat transfer medium flows within the first half pipe coil and cools the reactor to the hcc medium's utilization limit (see above). Below this temperature, liquid nitrogen is evaporated directly in the second half pipe coil or evaporated directly in the baffles. Fig. 4 illustrates the principle diagram of this type of reactor dual temperature control. Owing to the bigger temperature difference and very good heat transfer (evaporation), markedly high cooling outputs can be achieved via this type of design, even in small reactors. Here, a cleverly devised control design in conjunction with an appropriately designed reactor prevents the reaction product from crystallising on the container wall. Fig. 5 Compact CRYOTEMP®-units of a pilot plant. Temperature range -100° C / + 250° C. HTT energy systems GmbH Postfach 1922 32009 Herford /Germany Fullenbruchstr. 183 Օ 32051 Herford / Germany Tel efon : + 49 (0) 52 21/ 3 85-0 Telefax: + 49 (0) 52 21 / 3 85-12 Internet: www.htt.de E-Mail: info@htt.de