Adjust the dyeing process to save energy and increase efficiency

Since 2008, the prices of energy sources such as water, electricity, gas, and petroleum have risen continuously, and the price of dyeing and auxiliaries has also been constantly adjusted along with changes in the international energy situation. The implementation of the new labor law has further increased the human cost of the company. The cost pressures of enterprises are getting bigger and bigger, and the profit space is getting smaller and smaller. Especially in the textile printing and dyeing industry, it has reached a point where it is difficult to survive. Enterprises can not change the objective environment, to survive only focus on the internal business, and further adjust the process, energy efficiency. Focusing on this goal, we have made adjustments and applications in the following areas and achieved certain results.
1 Application of high-fixing reactive dyes The general fixing rate of reactive dyes is between 50% and 70%. After dyeing, a large amount of dye remains in the dye bath. Some of them are hydrolyzed dyes. The deeper the color, the more residual dyes are. . In view of this situation, some reactive dyes with high lifting power have been selected. They have two vinylsulfone groups and one monochlorotriazine, and all have excellent high absorptivity and high lifting power. The hydrolyzed dyes are easy to remove. For example, about 9% of reactive dyes are used for dyeing black, and only about 5% of reactive dyes are selected for high dyeing power.
The required dyeing depth can be achieved with a small amount of material and can reduce 2 to 3 times of water washing and reduce the discharge of sewage. It can save 130 yuan per ton of dark cloth.
2 The application of biological enzymes in the pretreatment process The biological enzyme refining technology is a revolutionary breakthrough in the traditional cotton pretreatment process. Low energy consumption, low wastewater discharge, low COD and BOD.
2.1 Traditional pre-treatment process: blank → scouring oxygen bleaching → water washing → peracid → deoxygenation → dyeing.
Process recipe:
30% hydrogen peroxide 5g/L
Sodium hydroxide 1.5g/L
Scouring agent LCF-123 1g/L
Stabilizer ST-201 1g/L
Process conditions: bath ratio 1:10, temperature 95 °C, heat 60min, and then natural cooling to 70 °C drained, hot water 80 °C in the pot for 20min, cooling to 60 °C, drainage, peracid, deoxygenation.
The cost of auxiliaries is: 370 yuan/t.
The caustic soda that remains on the fabric during the entire post-drilling period requires a large amount of hot water washing to produce a large amount of alkaline waste water. This both pollutes the environment and increases the load on the sewage treatment system.
2.2 Bio-scouring enzyme pre-treatment process: blank → biological scouring enzyme scouring → washing → staining.
Process recipe:
Scouring enzyme 2 g/L
Penetrant 1 g/L
Process conditions: 55 °C, heat 50min.
The cost of additives is: 365 yuan/t.
Compared with the pre-treatment of biological scouring enzyme and the one-bath treatment of boiled and bleached, the water cost is reduced by 50 yuan/t, the electricity cost is saved by 40 yuan/t, and the steam cost is saved by 200 yuan/t; the dyeing rate of fabrics treated with biological enzymes is improved. , Can save 0.5% ~ 0.8% of the dye, save time about 60min, reduce the amount of some of the pretreatment agent, simplify the process, shorten the process flow; biological enzyme refining does not require high temperature, high pressure, strong alkali and The conditions of strong acid can be used for catalytic decomposition reaction: not only the processing efficiency is high and the fabric is not damaged, the weight loss of the fabric is about 3%, the hand feels soft, and the strong damage is small; the biological enzyme is easily biodegradable, and the biological scouring enzyme does not cause environmental pollution .
Pre-treatment of medium and light-colored products, dark shades, and unclean cotton seed hulls.
3 Test and application of dyeing alternative alkali agent Soda ash has poor water solubility. It is easy to block the filter screen of the equipment. It is not easy to cause variegated pod disease. It is hard to wash after dyeing and reacts with calcium and magnesium ions in water with high hardness. White spot. After several years of improvement and perfection of dyeing substitute alkali agents, the product is more and more able to meet the needs of reactive dyeing. The amount of substitute base is 1/8 to 1/10 of the amount of soda ash, which can greatly reduce the amount of soda ash; the fastness to washing and wet rubbing after fixing with an alternative alkali is improved to varying degrees; Washing can reach the pH value of 3 times of soda ash washing, easy to wash, saving water and electricity; Compared with the soda fixing, fixing with a substitute alkali agent can save 240 yuan per ton of medium-dark fabric, and the COD value of the residual liquid after dyeing. Reduce the 1700 or so. In addition, as compared with soda ash, the red dye has a large influence on the coloring rate, and it is not suitable to dye with red as the main color.
4 The adjustment of pure cotton dyeing process takes dark color as an example, the original process curve is shown in Figure 1, and the adjusted process curve is shown in Figure 2.
As shown in Fig. 1 and Fig. 2, from the perspective of the adjustment of the process curve, the dyeing per cylinder can save 60 minutes and save electricity costs by 137 yuan/ton.

Figure 1 Pure cotton dyed dark traditional craft curve



Figure 2 pure cotton dyeing dark adjustment process curve
5 One-bath dyeing process is applied to the dyeing of fabrics with multi-component fibers (eg, more than 3 types of fibers). The conventional dyeing process requires multi-bath dyeing, which not only consumes time and energy, but also discharges more pollutants. Through trial and analysis, selection of auxiliaries, and process adjustment, we try to control the two-step or two-bath dyeing of one bath to truly achieve maximum energy saving, emission reduction, and consumption reduction. For example, there are four types of fibers in the fabric: polyester, cotton, viscose, and nitrile, which are first heated at 98°C for 30 minutes, then cooled down to 60°C and added with anti-settling agent for 15 minutes. Then disperse dyes are added to warm up to l30°C, and the temperature is reduced. Restore cleaning, draining, washing, dyeing cotton and viscose.
6 acid soaping agent commonly used soaping agent is an alkaline soaping agent, after dyeing need 2 to 3 water, and then soaping acid. The use of an acidic soap lotion to reduce the number of peracid links and a one-time water wash resulted in a significant reduction in the cost of dyeing dark products, which was reduced by approximately $100/t.
7 Improve the success rate of dyeing at one time Increase the success rate of dyeing at one time, reduce the rate of repair, reduce energy consumption, reduce pollutant discharge, and increase production efficiency. Generally, the following measures are taken:
a. Strengthen process monitoring, strictly implement processes, and timely monitor equipment conditions;
b. Timely tests of different batches of dyes and auxiliaries, according to the actual situation of the test to improve the process, so that production and laboratory consistency;
c. New orders through the proofing, replicating, lofting improve the dyeing rate of a pass, according to different batches of yarn back to the single, review the production process, timely adjustment of the production process, to avoid the color change caused by the replacement of raw materials, the problem of color correction.
8 Conclusion Through the above process adjustment and application, we have successfully passed the difficult first half of 2008. Although various costs have continued to rise, but under the premise that the prices of products for dyeing and finishing have not been adjusted, we have absorbed some of the cost-rising factors and achieved better economic benefits.