ENERGY RECOVERY IN A DYEING CLOTH PLANT

Ziel

The object of the programme is to prove the technical feasibility and the overall economic validity of modifying an existing plant for dyeing cloth in order to recover heat and to reduce water consumption.
The risks for the operations arising from incidental mixing of the liquids used for the dyeing work, are considerably reduced. An annual energy saving of about 444 TOE is to be expected at project level.
The final results of the measurements, carried out during 6 months with regard to 6505 cycles, corresponding to 666,442 kg of dyed cloth, revealed the following savings:
- 47, 227 m3 of preheated softened water, corresponding to a heat saving of
53,9 TOE
- 2,395,603 kg of condensate, corresponding to a heat saving of 20,4 TOE.
The measured savings were quite different from those expected being.
256% for softened water
34,7% for condensate
103% from the heat from softened water
29,5% for the heat from condensate.
Consequently, the overall heat saving, attained from cooling water and condensate, was 61,2% of the forecast total recoverable heat.
This project is carried out in a plant of the firm Lanerossi, in the industrial area of Prese, near Schio (Vicenza), Italy.
The dyeing process requires the tanks to be filled with softened water, preheated to 45 - 50 deg. C, together with the cloth to be dyed, the bath to be steam heated up to the suitable temperature and kept at this temperature for a suitable time, then water cooled down to room temperature and the dyed cloth to be rinsed and discharged.
In the old design of plant the heating steam and the unconditioned cooling water ran through the same heat exchanger in different times; the risk of defiling the condensate by the unconditioned cooling water owing to leakage from interception valves and to incorrect timing of opening and closing of them, was considerable, so neither heat nor condensate was recovered for operation safety's sake and both cooling water and condensate were discharged into sewer.
In the modified plant, the dyeing bath is steam heated and kept at thedyeing temperature by one heat exchanger and cooled by a different one crossed by softened water, which is then used for filling the tanks to prepare dyeing baths that need preheated softened water: a saving of both water and heat is therefore attained.
There is no more risk of condensate pollution by unconditioned water, so condensate is sent again to the steam boiler; one more saving both softened water and heat is therefore retained.
This only remaining danger is a pollution of condensate and of conditioned cooling water by the dyeing bath owing to damage to the heat exchangers; therefore a proper control instrumentation is to be inserted in the circuits of both heating and cooling fluids, to actuate the discharge of the fluids if they show themselves polluted, at the same time signalling the trouble.
The following savings are foreseen to be obtainable by the modified plant in comparison with the old one (for 21800 cycles for year):
Cooling water: 3.35 m3 per cycle
Condensate: 1.04 m3 per cycle
Energy: 444 tep per year
A 7 years endurence is foreseen for the equipment of the modified plant. The work program of the firm involved the carrying out of the project on 30 tanks. Corresponding to a charge of 4020 kg, for an average production of 16000 kg of dyed cloth every day.

Programm/Programme

ENG-ENALT 1C - Programme (EEC) of financial support for projects to exploit alternative energy sources, 1979-1984

Thema/Themen

1.6 - INDUSTRY

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

DEM - Demonstration contracts

Koordinator

Lanerossi SpA

EU-Beitrag

Keine Daten

Adresse

Via Pasubio 149
36015 Schio Vicenza
Italien

Gesamtkosten