Cel
The purpose of the project is to design, manufacture and install two original mains frequency (50 hz) induction preheaters, one for heating aluminium billets and the other for heating copper alloy billets prior to extrusion. The preheating temperature is 450c for aluminium and is within the range 700-950c for copper alloys. The construction features of the preheater allow remarkable energy savings to be attained. It was also necessary to assess the long term reliability of the preheaters in order to investigate their suitability for wide scale adoption and total operation cost.
Energy consumptions achieved under operating conditions are compared with the design predictions for a range of alloys and billet lengths and with the equivalent figures on conventional single layer coil heaters. The saving in energy consumption varies from 26% to 33% of the conventional coil input for the aluminium preheater and from 25% to 36% for the copper alloy preheater. These figures represent savings of 59 - 76 kwh/tonne for aluminium and 55 - 127 kwh/tonne for the copper alloys.
The specific energy consumption at the heater transformer input terminals varied from 1% above to 8% below the target values declared in the contract for the aluminium preheater. The corresponding consumption of the copper alloys from 1% above to 14% below the revised design figures based on measured values of resistivity and heat content. These measurements were made as part of the contract and corrected erroneous data, previously used within the industry, on the physical properties of the alloys. These measurements provided valuable information for more accurate inductor design.
Each preheater incorporates a new design of winding using a multi-layer configuration to reduce substantially the overall energy consumption per ton of billets heated. The multilayer concept enables a greater effective cross - sectional area of copper conductor to be used than with a single layer winding; so the current carrying capacity is not limited by the current penetration depth. This feature therefore substantially reduces the effective a.C. Resistance of the winding and, therefore, the energy loss. Furthermore, the design incorporates edge cooling of the winding strip using deionized water; the conventional hollow conductor is not necessary for this reason.
The project, commissioned by the electricity council research centre, capenhurst, chester, was located at delta (manganese bronze) ltd, ipswich, england for the aluminium billets preheater and at alcan extrusion ltd, oxon, england, for the copper alloy billets preheater.
The induction preheater is designed to heat 178 mm diameter per 660 mm long aluminium billets to 450c at a rate of 59 per hour, which is equivalent to 2.7 tonnes per hour. It is also designed to heat 59 - 152 mm diameter billets per hour to the same temperature, equivalent to 2 tonnes per hour. The expected energy consumption for 178 mm billets was 171 kwh/tonne and for 152 mm billets, 178 kwh/tonne. The peak rating of the designed heater is 600 kw, 3.5 mva when used with 178 mm diameter billets.
With regard to the induction preheater for copper alloys, the dimensions of the treated billets are 175 mm diameter and 660 mm length; they have to be preheated to 925 c at a rate of 15 per hour, which is equivalent to 2.1 tonnes per hour. The expected energy consumption is different for different alloys, as follows.
Kwh/tonne alloy specification
119 t1
135 w1
120 s1
135 c a1
The expected peak rating for the heater is 450 kw, 25 mva when used with c a1 billets. The expected duration of the work, which began on november 1st, 1979, was 22 months.
Temat(-y)
Zaproszenie do składania wniosków
Data not availableSystem finansowania
DEM - Demonstration contractsKoordynator
CH1 6ES Chester
Zjednoczone Królestwo