Super critical fluid dyeing

Evaporate Curve Gas Super Cretical Fluid Dyeing Machine Prepared By : Mazadul Hasan sheshir ID: 2010000400008 13th Batch (session 2009-2013) Department : Wet Processing Technology Email: mazadulhasan@yahoo.com Blog : www. Textilelab.blogspot.com (visit) Southeast University Department Of Textile Engineering I/A 251,252 Tejgaon Dhaka Bangladesh Prepared By : Total Textile Process at a Glance Introduction The textile industry is believed to be one of the biggest consumers of water. In conventional textile dyeing, large amounts of water are used both in terms of intake of fresh water and disposal of wastewater. On average, an estimated 100–150 litres of water is needed to process 1 kg of textile material, with some 28 billion kilos of textiles being dyed annually. Water is used as a solvent in many pretreatment and finishing processes, such as washing, scouring, bleaching and dyeing. Hence, the elimination of process-water and chemicals would be a real breakthrough for the textile dyeing industry, and it seems this has now come to fruition , with the launch of the world’s first ever industrial dyeing machines that uses super carbon dioxide (CO2) as a replacement for water. The manufacturer behind thissystem is the Dutch company, DyeCooTextile Systems BV. Years of extensiveresearch and development has goneinto producing the novel, completelywater-free dyeing process which hasconsiderable lower operational costscompared to conventional dyeingprocesses. Principle ‘The principle of dyeing with CO2 was invented in Germany twenty-five years ago. Developing a well functioning machine, however, turned out to be too expensive.’ DyeCoo Textile Systems’ parent company, Feyecon, began tackling this issue ten years ago in partnership with the Delft University of Technology and Stork. This ultimately resulted in DyeCoo (which was formed in 2008), which literally means dyeing with CO2. Different between conventional & supercritical CO2 dyeing Supercritical Fluid A supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. It can effuse(spill,shed) through solids like a gas, and dissolve materials like a liquid. In addition, close to the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be "fine-tuned". Supercritical fluids are suitable as a substitute for organicsolvents in a range of industrial and laboratory processes. Carbon dioxide and water are the most commonly used supercritical fluids, being used for decaffeination and power generation, respectively. PropertiesPropertiesProperties Solvent Molecular weight Critical temperature Critical pressure Critical density g/mol K MPa (atm) g/cm3 Carbon dioxide (CO2) 44.01 304.1 7.38 (72.8) 0.469 Water (H2O) (acc. IAPWS) 18.015 647.096 22.064 (217.755) 0.322 Methane (CH4) 16.04 190.4 4.60 (45.4) 0.162 Ethane (C2H6) 30.07 305.3 4.87 (48.1) 0.203 Propane (C3H8) 44.09 369.8 4.25 (41.9) 0.217 Ethylene (C2H4) 28.05 282.4 5.04 (49.7) 0.215 Propylene (C3H6) 42.08 364.9 4.60 (45.4) 0.232 Methanol (CH3OH) 32.04 512.6 8.09 (79.8) 0.272 Ethanol (C2H5OH) 46.07 513.9 6.14 (60.6) 0.276 Acetone (C3H6O) 58.08 508.1 4.70 (46.4) 0.278 Critical properties of various solvents shows density, diffusivity and viscosity for typical liquids, gases and supercritical fluids Comparison of Gases, Supercritical Fluids and Liquids Density (kg/m3) Viscosity ( µPa∙s) Diffusivity (mm²/s) Gases 1 10 1–10 Supercritical Fluids 100–1000 50–100 0.01–0.1 Liquids 1000 500–1000 0.001 In addition, there are: • No surface tension in a supercritical fluid • No liquid/gas phase boundary • By changing the pressure and temperature of the fluid, can be "tuned" to be more liquid- or more gas • Soluble in material in the fluid • Solubility in a supercritical fluid tends to increase with density of the fluid (at constant temperature) • Density increases with pressure, solubility tends to increase with pressure • Relationship with temperature is a little more complicated • At constant density, solubility will increase with temperature All supercritical fluids are completely miscible with each other so for a mixture a single phase can be guaranteed if the critical point of the mixture is exceeded. The critical point of a binary mixture can be estimated as the arithmetic mean of the critical temperatures and pressures of the two components, Tc(mix) = (mole fraction A) x TcA + (mole fraction B) x TcB. For greater accuracy, the critical point can be calculated using equations of state, such as the Peng Robinson, or group contribution methods. Other properties, such as density, can also be calculated using equations of state. Supercritical Carbon Dioxide(CO2) Carbon dioxide is a readily available, cheap, recyclable and is non-toxic and non- flammable. Above the temperature of 31.6 oC and pressure of 73 atm carbon dioxide exhibits physical properties, which are intermediate between those of gases and liquids. These conditions are called supercritical conditions and are readily achievable using commercially available equipment. Supercritical carbon dioxide is able to dissolve a range of chemical substances including organic substrates, catalysts, and light gases. Its main advantage however comes from the fact that this solvent can be easily turned into a gas by simply releasing the pressure leaving no solvent residues and requiring no evaporation or separation. Benefits • Applied a clean solvent • Improved control and fine-tuning of process • Developed a remarkably selective synthetic process • Minimised waste & Increased atom utilization • Minimised handling and purification procedures Supercritical Carbon Dioxide(CO2) Properties • Low cost • Non-Toxic • Density: liquid • Viscosity: Gas • Recycling up to 90% • Inert • Non-explosive • Low critical point • Pressure: 73.858 ± 0.005 bar • Temperature: 31.05 ± 0.05 ºC [...]... vinylsulfone-based dye on nylon and wool •ES -dyeing on wool fibers showed extremely low color yields after extraction (no reaction) •94% fixation at 180 oC/ 3500 psi on wool Dyeing Procedure Dyeing polyester with disperse dyes in supercritical CO2 Supercritical fluids are highly compressed gases which possess valuable properties of both a liquid and gas Any gas above its critical temperature retains the free... separator.” To read more about supercritical fluid dyeing technology Dyeing Procedure Fastness assessment 1 Wet fastness was determined according to UNI 7638 (ISO 105-C 01/03/04) 2 For the determination of fastness to artificial light, a Xenotest Hanau 150S (Heraeus) 3 apparatus was employed, equipped with a 1500 W xenon arc lamp, 4 according to UNI 7639 (ISO 105-B02) Dyeing Procedure Dyeing Conditions Extraction... becomes supercritical, a state of matter that can be seen as an expanded liquid, or a heavily compressed gas In short, above the critical point, carbon dioxide has properties of both a liquid and a gas In this way supercritical CO2, has liquid-like densities, which is advantageous for dissolving hydrophobic dyes, and gas-like low viscosities and diffusion properties, which can lead to shorter dyeing. .. and auxiliaries High energy requirements Dyeing in Supercritical CO2 Completely avoids the use of water No waste water at all Unreacted dye remains as powder No need for dispersing and leveling agents Requires only 20% energy of conventional dyeing Dyeing, washing and drying times are 3-4 Only 2 to 2.5 hours per batch hours per batch Drying is required after dyeing process Not required as CO2 is released... drying Recycling Solvent Colorants Environmental friendly Both economic and ecological Having a low critical temperature Disadvantage Investment Solve colorants Time of process Dyeing Procedure Dyeing of polyester Supercritical CO2dyeings were performed using an SFE 400 supplied by SUPELCO, equipped with a 50 cm3 internal volume vessel The operating pressure could be set up to 6000 psi, managed in 100... partnership with DyeCoo in order to produce textiles dyed without water 4 Yeh group dyeing the fabrics with this machine branded as DryDye™ Fabrics Comparative Energy Requirements* (kJ): Conventional scCO2 Pretreatment 4555 4555 Dyeing 45250 30625 Post Treatment 3800 0 Total 53605 35180 Energy Savings 34.37% Supercritical fluid processing Machine ... packages was woven into a “sock” and evaluated for uniformity Problems with Conventional Water -Dyeing Machine Problems 1.In conventional method of dyeing textiles undergo multiple processes 2 In these processes water, dyes, and other auxiliaries are used to enhance the efficiency of dyeing process 3 After dyeing a subsequent drying process with high energy consumption is necessary 4.The cost of waste... in SC-CO2 Dye-Fiber Reaction in SC CO2 Sulfonyl-azo-dyes Dyeing Procedure Dyeing Procedure 1 Add fiber and dye to vessel 2 Pressurize system (with CO2) up to 800 psi and stir at approximately 850 rpm 3 Heat to required temperature (100 -180 ºC) 4 Pressurize to 3500 psi; hold for 2 hours 5 Release pressure, remove fabric Dyeing Procedure CO2 Dyeing System (1) Gas cylinder of CO2, (2) High pressure pump,... jacket 3 5 2 1 4 Dyeing Procedure High Pressure Batch Reactor Dyeing Procedure Testing Dye-Fiber Reaction •Measure color strength (K/S) of each dyed fiber •Wash fiber with acetone (remove surface dye) •Conduct soxhlet extraction using ethyl acetate (to remove unreacted dye) •Compare effect of vinylsulfone reactive group on dye fixation Results Dyeing Procedure Comparison of Dyed Fabrics Dyeing Procedure... •It has a critical point within the range which is readily manageable by technical means (31C and 73 bar) •It is non-toxic, non-hazardous and low cost •It is nonflammable and non-corrosive Dyeing Procedure Advantage No waste water (problem in textile industry) No require additives No final drying Recycling Solvent Colorants Environmental friendly Both economic and ecological Having a low critical temperature . means dyeing with CO2. Different between conventional & supercritical CO2 dyeing Supercritical Fluid A supercritical fluid is any substance at a temperature and pressure above its critical. the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be "fine-tuned". Supercritical fluids. (46.4) 0.278 Critical properties of various solvents shows density, diffusivity and viscosity for typical liquids, gases and supercritical fluids Comparison of Gases, Supercritical Fluids and Liquids Density