Objective
The aim is to save thermal energy and water in wool dyeing mills by recycling dyeing baths.
The innovative aspect is the recycling of the bath after dyeing which leads to direct hot water savings.
The goals are :
- an energy saving of about 3500 ECU/Y on the basis of 157 ECU/TOE
- a water saving of about 2400 ECU/Y
- an investment cost of about 22000 ECU
- a cost of maintenance of about 2200 ECU/Y
- A payback time of about 6 years.
All these data have been calculated using the demonstration dyeing autoclave of 160 kg and 2000 l.
1) The dye exhaustion speed is well mastered by a pH regulation, thanks to the CRS "TEINTOPROG" R (new version).L% 2) The colorimetric differences between the first dyeing and the following recyclings are not higher than those of two different dyeings.L% 3) Amount of water used during the 1st experiment :L% 1st dyeing : 15 lL% Recyclings : 5 x 1 l = 5 lL% Total........20 l (instead of 90 l)L% The energy savings are directly related to the amount of water saved which would have been preheated at 75 deg C under current dyeing conditions.L% The first results obtained meet the expected goals.L% Next step will consist in multiplying the number of test using :L% - industrial conditions of experimentL% - different types of shadesL% - other dyeing processesL% - fastness and spinning testsL%
At the end of the first dyeing, the liquor is kept up at a temperature of 90 deg C. Then it is strengthened with dyestuffs and chemicals. The hot water, which has been picked up by the wool during its delivery, is replaced by cold water which drops the temperature to 75 deg.C. The exhaustion dye speed of the first dyeing is regulated by the colorimetric regulator sensor (CRS) "TEINTOPROG" R designed by ITF-NORD and made by COMEUREG SA (FR).
Therefore, the first recycling starts at 75 deg C instead of 15-20 deg C for a classical wool dyeing. A new version (designed by ITF-NORD), of the CRS "TEINTOPROG" R enables to regulate and visualize the dye exhaustion speed by mastering the drop in the liquor pH from 7,7 to 5.5. During this phase, temperature is kept up at about 75 deg C. When the pH threshold is reached, the dyestuff exhaustion is completed by a regulated increase in temperature up to 98 deg C thanks to CRS "TEINTOPROG" R.
The cycle as a whole comprises 1 dyeing and 5 similarrecyclings.
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
59061 ROUBAIX CEDEX
France