Textile Printing And Dyeing Waste Gas Pollution Needs To Guard Against Experts Calling For Bright "Standard" Sword.

< p > a few days ago, a dispute about the source of haze in Beijing focused on the contribution rate of automobile exhaust to PM2.5.

In fact, < a href= "http://www.91se91.com/news/list.aspx? ClassID=101112107105" > textile printing and dyeing > /a > exhaust gas pollution can not be underestimated.

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Gong Yanzai, an associate professor of the environmental protection standards committee of the Chinese Federation of environmental protection, and an associate professor of the school of materials science and engineering, Beijing Institute Of Fashion Technology, told reporters in an interview with science and Technology Daily: "exhaust gas from textile printing and dyeing industry is also a large contributor to PM2.5, but it has not received enough attention."

He pointed out that at present, there is no specific emission standard for textile printing and dyeing industry. The lack of standards makes the relevant waste gas treatment and monitoring technology almost blank.

"It is imminent to formulate the emission standards for textile printing and dyeing industry, and to speed up the research and development of textile waste gas treatment and monitoring technology."

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< p > < strong > textile printing and dyeing contributes 8.8%VOCs < /strong > /p >

< p > < 2011 - 2020 unconventional control pollutants emission inventory analysis and Prediction Research Report > data show that in 2008, China's textile printing and dyeing industry VOCs (volatile organic compounds) emissions accounted for 8.8% of the total VOCs emissions from different sources, accounting for more than 30% of VOCs emissions from industrial processes.

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< p > VOCs is a general term for a class of organic pollutants which are ubiquitous and complex in the air. It mainly includes alkanes, olefins and aromatic hydrocarbons. In general, these volatile gases will directly pollute the air directly after they are discharged into the atmosphere.

In addition, VOCs can also generate two organic aerosol particles through complex photochemical reactions, becoming one of the important sources of < a href= "http://www.91se91.com/news/list.aspx ClassID=101112107108" > PM2.5 < /a >.

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< p > "8.8% is a very large proportion. If we can take some relevant measures at the source of pollution to control the exhaust emissions from the textile and dyeing industry, it will undoubtedly bring about an effective improvement in the quality of the ambient air."

Gong pointed out.

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< p > for a long time, it is difficult to clarify the specific production processes or links of the exhaust gases emitted from the textile and dyeing industry.

The research team led by Gong Jun traced the problem and thought that the exhaust gas from textile printing and dyeing industry came from two main aspects: one is the spinning process of chemical fiber, the other is Textile Pretreatment and functional finishing process. Two.

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< p > taking the spinning process of viscose fiber chemical fiber as an example, it is necessary to make the raw material into spinning solution, and a large amount of carbon disulfide is added to the spinning process, so the spinning process will release harmful gas substances mainly composed of hydrogen sulfide, carbon disulfide and sulfur dioxide.

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< p > heat treatment machine is an important part of the pretreatment process of textiles.

When heat setting, all kinds of dye auxiliaries and coating auxiliaries on textiles will be released, so there will be a large amount of VOCs (organic volatiles) released at the end of the exhaust pipe.

These organic gases are mainly organic compounds such as formaldehyde, polybenzene and aromatic hydrocarbons.

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In the process of functional finishing of textiles < p >, the exhaust gas comes mainly from two links.

In the hot melt dyeing process of polyester disperse dyes, high temperature causes some small molecules to sublimate the dye into exhaust gas.

Cotton fabric's non iron and flame-retardant finish must be baked. As a result of adding some chemical additives, formaldehyde and other aldehydes and ammonia can be released during baking.

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< p > < strong > textile waste gas is more difficult to supervise than waste water. It is urgent to have special standard < /strong > < /p >.

< p > textile printing and dyeing industry has always been a traditional polluter in China and produces a lot of waste water and waste gas every year.

"It takes seven or eight kilograms of chemical additives to produce a kilogram of clothes per kilogram, and the pollution caused by it is large enough to be imagined."

Gong told Science and technology daily.

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< p > as early as 1992, China issued and implemented the "discharge standard for water pollutants in textile dyeing and finishing industry", and strictly controlled the discharge of textile printing and dyeing wastewater.

In 2012, the Ministry of environmental protection completed the first revision of the standard. The revised standards are more stringent than before, and some new pollutant emission limits have been added.

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Compared with the increasingly stringent wastewater discharge standards, < p > there is no special emission standard for textile printing and dyeing waste gas.

Gong said that, compared to the particularity of textile and dyeing industry, the existing "comprehensive emission standards for atmospheric pollutants" and "odor pollutants emission standards" set Limited indicators, which can not fully cover the types of textile waste gas pollutants.

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< p > "in fact, textile waste gas is more concealed and more difficult to monitor than waste water. Due to the lack of specific and specific standards, a large number of textile waste gas is basically discharged directly into the atmosphere through exhaust tanks or unorganized forms."

Gong said frankly.

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< p > under the appeal of industry experts, by the China Environmental Protection Federation environmental technology standard research Specialized Committee application, "textile printing and dyeing industry atmospheric pollutants emission standards" was incorporated into the 2013 national environmental protection standard revision project.

Gong is the person in charge of the standard project team.

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< p > Gong believes that the emission standards of textile printing and dyeing industry should be promulgated to urge textile enterprises to control waste gas pollution and guide enterprises to improve their production technology, so as to effectively control the air pollution and improve the air quality in some areas.

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< p > < strong > accelerate the research and development of textile waste gas monitoring and treatment technology < /strong > < /p >

After the introduction of emission standards for air pollutants in textile printing and dyeing industry, how to ensure the implementation of standards from the technical level is a question P has been thinking about.

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< p > at present, the waste gas monitoring for textile enterprises mainly adopts on-site sampling bags to collect and bring back to laboratory for testing and analysis.

In Gong's view, this air collection mode can not fully and truly reflect the exhaust emissions of enterprises. "We need to develop an on-line emission monitoring system to reflect the emissions of textile enterprises in real time."

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After the introduction of < p > a href= "http://www.91se91.com/news/list.aspx ClassID=101112107101" > emission standard < /a >, under the strong constraint of standards, textile enterprises need to increase R & D of waste gas treatment technology and improve relevant production equipment and technology to reduce air pollutant emissions.

Gong pointed out: "at present, domestic textile waste gas treatment technology is basically in a blank state. We must speed up the development of a good economic and effective waste gas treatment technology in the consideration of the textile enterprise's bearing capacity."

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