Dyeing process operation

Atomic- Vapor Laser Isotope-Separation. Although the technology has been around since the 1970s, laser isotope separation has only recently matured to the point of industrialization. In particular, laser isotope separation for the production of fuel and moderators for nuclear power generation is on the threshold of pilot-plant demonstrations in several countries. In the atomic vapor laser isotope-separation (AVLIS) process, vibrationaHy cooled U metal atoms are selectively ionized by means of a high power (1—2 kW) tunable copper vapor or dye laser operated at high (kHz) repetition rates (51,59,60). 

Alkali is usually added in a second stage. However, with low reactivity high affinity dyes it is possible to add the alkah at the beginning of the dyeing process and control the rate of uptake and chemical reaction by temperature control. With high affinity dyes the exhaustion takes place at low temperature rapidly before the chemical reaction becomes significant. If dyes are carefully selected or synthesized to have identical dye uptake it is possible to include all the electrolyte from the beginning and operate an "ah-in" technique. 

In 1980, approximately 111,000 t of synthetic organic dyestuffs were produced in the United States alone. In addition, another 13,000 t were imported. The largest consumer of these dyes is the textile industry accounting for two-thirds of the market (246). Recent estimates indicate 12% of the synthetic textile dyes used yearly are lost to waste streams during dyestuff manufacturing and textile processing operations. Approximately 20% of these losses enter the environment through effluents from wastewater treatment plants (3). 

Natural dyes processed for the market do not undergo any chemical operations. Those operations iavolved are purely physical, such as grinding, spray or vacuum dryiag, and water or solvent extractions. None of these operations create any great environmental problems. 

Contamination from entrained BW and solids may render steam unsuitable for process operations, including food preparation, sterilization of surgical equipment, textile dyeing, hydrolysis reactions, vulcanizing, and the like. 

Recent estimates indicate 29t of the synthetic textile dyes used yearly are lost to waste streams during dyestuff manufacturing and textile processing operations. Approximately 20% of these losses enter the environment through effluents from wastewater treatment plants. 

The main route by which dyes enter the environment is via wastewater, bodi from dieir manufacture1 and their use. Accurate data on dyes released into die environment are not available, although lists of materials released to the environment from die processes operated for the production of some triarylmediane dyes have been reported. 

Pastel and Sausa [110] detected N02 (LOD 400 ppb at 1 atm) with a one-photon absorption photoacoustic process (Fig. 13) by means of A X2B1(0,8,0)-X 2A1(0,0,0). This work, which employed a dye laser operating near 454 nm, was the first report of a high-resolution visible N02 photoacoustic spectrum. They found that low laser intensities favor N02 photoacoustic detection, whereas high laser intensities favor NO detection through REMPI (LOD 160 ppb). Fig. 15 shows the high-resolution photoacoustic spectrum of N02 and the NO REMPI spectrum. 

PENTEX FR is a nonlonic/anlonic blended surfactant that is a biodegradable product for textile wet processing operations. Typical uses are in preparation of fabrics (bleaching), boil-off, and scouring of yarns and fabrics, soaping of fast dye yarns and fabrics particularly when dyed with fiber reactive dyes. 

In the first step of the partnership, BASF provided its eco-efficiency expertise (see Section 6.1.3 for detailed discussion of BASF eco-efficiency analysis) to help Moroccan textile dye works operate in a more efficient and environmentally friendly way. Based on the eco-efficiency analysis and the experience of many years with products and processes in the textile sector, BASF developed a software package, which was given to Moroccan companies free of charge. The software tool substantially simplifies the compilation of an eco-efficiency analysis. It uses key technical data to calculate how the manufacturing process can be improved. 

The largest ZOSS and ZOFA systems currently in operation are used in the textile industry for recycling wash water in dyeing processes and for renovating caustic solutions (, T). Systems are also being used for oil-water separation, nuclear Industry applications, and food processing. 

It has been stated (J.S.D.C., 1968, 84, 66) that the productivity of one man looking after a group of five high pressure dyeing machines was increased by 37 per cent by the introduction of automatic process control. The reason is that there are a number of occasions when more than one operation should be carried out simultaneously and this cannot be done manually. Another factor is the human inability to move and react mentally with instantaneous speed. Many more examples could be quoted to demonstrate the advantage of the elimination of human memory and manual manipulation in the operation of dyeing processes. 

On the other hand, the processing-fastness-requirements depend on the very special sequence of operations that are made around the actual dyeing process. The best representation of the expert s knowledge in this area is given by a set of rules that catches the expert s considerations when he derives these requirements. 

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