Cleaner Technology Transfer to the Polish Textile ... - Miljøstyrelsen

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Figure 1. Vald. Henriksen Jet. Figure 2. A reactive dye-stuff. 90 3.5 Reclamation of reactive dyeing process water by chemical precipitation Hans Henrik Knudsen, Henrik Wenzel, Søren Ellebæk Laursen, Institute for Product Development, Denmark, Gert Holm Kristensen, VK1 Institute for the Water Environment, Denmark and Jørgen Cederholm, Martensens Fabrik Ltd. Denmark. Reactive dyeing of cotton Reactive dyeing of cotton is the most common wet treatment of textile processes world-wide. Today batch dyeing is dominating and increasing. Batch processes typically take place in a jet machine, where both the liquor and textile are circulated to reach a quick process performance. Reactive dye-stuffs have utilization degrees of 60-90%. The remaining dyestuff hydrolysate has to be washed out during a rinse and, thus, ends up in the waste-water. Reactive dye-stuffs consist of chromofore and reactive components. Chromofores are the coloured part of the molecule, typical an azo group between aromatic groups, each carrying anionic sulfonic acid functional groups. The reactive are typical triazine, pyrimidine or sulfatoethylsulphone.
Figure 3. Typical process water from batch recipes. Adsorption on metal salt hydrolysates Process water Essential for the application of water reclamation technique is: • Dye-stuff content typically varies between 0,5-1 g/l in dye-baths. • Salinity typically varies between 40.000-80.000 mg/l. In the preceeding rinse salinity will decrease by a factor 3 in each batch rinse. • Temperature the dye-bath and first batch rinse need a temperature >50-60°C, the following rinse a temperature of 90-95°C. • Additives process water contains dispersing and complexing agents • pH typically >11 in the dye-bath, followed by neutralisation with addition of acetic acid. After neutralisation pH will not be above 10. Chemical precipitation The mechanism in the precipitation with aluminium compounds, as Al2(SO4) 3 and ironsalts, as FeCl3 , is formation of large metal hydrolysates and entrainment of adsorbable compounds. Decomposition by Fe(II) Fe(II)/Ca(OH) 2 decomposes azodyes by a reduction reaction. Lime is dosed to reach pH at 9, and the hydroxides sedimentates under entrainment of the decomposed dye-stuffs. Figure 4. Dye-stuff decomposition by Fe(II)/Ca(OH) 2. 91
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1999 Cleaner Technology Transfer to
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Content Preface 5 Summary 7 Part 1.
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Summary Areas of pollution preventi
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1.1 Programme description Programme
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Focus on cost-effective options par
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2.1 Introduction This Idea catalogu
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Topic 1. Minimization in consumptio
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Topic 3. Optimization of cooling by
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Topic 5. Temperature control of coo
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Topic 7. Minimization of water for
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Topic 9. Exchange of batch dyeing m
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Topic 11. Introduction of in situ r
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Topic 13. Optimization of counter c
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Topic 15. Procedure for cleaning of
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Topic 17. Change from batch to cont
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Topic 19. Desizing with enzymes Cas
Page 39 and 40: Topic 21. Substitution of APEO dete
Page 41 and 42: Topic 23. Change from monoreactive
Page 43 and 44: Topic 25. Substitution of carriers
Page 45 and 46: Topic 27. Substitution of afterchro
Page 47 and 48: Topic 29. Dry conditioning Case ill
Page 49 and 50: Topic 31. Mechanical softening proc
Page 51 and 52: Topic 33. Re-use of pure cooling wa
Page 53 and 54: Topic 35. Re-use of chemically load
Page 55 and 56: Topic 37. Re-use of water from rins
Page 57 and 58: Topic 39. Separation techniques for
Page 59: Topic 41. Evaporation and reclamati
Page 63 and 64: 3.1 Introduction During the Cleaner
Page 65 and 66: The ever increasing demand to shade
Page 67 and 68: The dyeing process The reactive dye
Page 69 and 70: hardness in water and extract from
Page 71 and 72: Figure 7. The effect of complexing
Page 73 and 74: Reduced process time Seilund and C.
Page 75 and 76: Tabel 1. Degradation af APEO. Table
Page 77 and 78: Alkylphenol ethoxylates (APEO) This
Page 79 and 80: 3.4 Reclamation and re-use of proce
Page 81 and 82: Figure 1. Typical process waters fr
Page 83 and 84: Figure 2. The dependency of precipi
Page 85 and 86: Advantages and limitations of the w
Page 87 and 88: Figure 5. Environmental benefits of
Page 89: Kolb, M., B. Funke, H.P. Gerber and
Page 93 and 94: Table 1. Selected chemical for delc
Page 95 and 96: Figure 9. Profiles for dye-stuff pr
Page 97 and 98: Conclusions The optimal use of chem
Page 99 and 100: The conclusion based on lab-scale r
Page 101 and 102: During the period from 1992 to 1995
Page 103 and 104: 3.8 Environmental labelling John Ha
Page 105 and 106: The products to be labelled with th
Page 107 and 108: 3.9 Improvement of the rinsing effi
Page 109 and 110: Table 1. Documentation of savings i
Page 111 and 112: Part 4. Implementation projects 111
Page 113 and 114: 4.1 Introduction On the basis of th
Page 115 and 116: and a continued pumping is achieved
Page 117 and 118: The new recipes were tested in a la
Page 119 and 120: 4.4 Savings and substitution of env
Page 121 and 122: To illustrate the order of magnitud
Page 123 and 124: Data sheet Publisher: Ministry of E
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