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Can environmental protection pass without benzene homologues in the paint

can environmental protection pass without benzene homologues in the paint

September 22, 2020

benzene homologues, namely aromatic hydrocarbons (abbreviated as machs), are the general name of benzene and derivatives. They are common pollutants emitted by human activities. The absolute number of benzene homologues in the full sense can be as high as more than ten million, but in the general sense, benzene homologues mainly include benzene, toluene, ethylbenzene, xylene, trimethylbenzene, styrene, phenol, aniline, chlorobenzene, nitrobenzene, etc, Among them, benzene, toluene, ethylbenzene and xylene are the representative substances. Some people also call benzene series BTEX for short

with the increasingly strict control of VOCs emission by the environmental protection department, the pressure of many paint users has increased sharply. The discharge outlet has even been equipped with automatic air pollutant monitoring instruments and remotely monitored by the environmental protection department. If it exceeds the standard, it will alarm and may be punished by the environmental protection department. Therefore, some paint using units require paint suppliers to supply benzene free (benzene series) paint to reduce pressure. Why? Is this method effective? The editor analyzes it here for your reference

when it comes to the standard emission of air pollutants, corresponding standards must be followed. Previously, the "wonderful combination of gud belt and fiberform process B air pollutant emission standard" was implemented, and later corresponding emission standards were formulated according to different industries (such as GB, GB, GB, GB, GB, etc.). However, at present, there is no national standard for the emission of air pollutants from industrial coating processes. However, some provinces and cities have issued relevant standards, For example:

db31/Shanghai local pollutant emission standard "emission standard of air pollutants for automobile manufacturing (coating)"

DB11/(Beijing) emission standard of air pollutants for industrial coating process

db32/(Jiangsu Province) emission standard of volatile organic compounds for surface coating (automobile manufacturing)

db33/(Zhejiang Province) Emission standard of air pollutants in industrial coating process

why do some paint using units require paint suppliers to supply benzene free (benzene series) paint to deal with environmental protection inspection? The reason, of course, lies in the emission standards

take the GB emission standard of air pollutants as an example, the pollutants most related to coating and coating listed in it

other local emission standards of air pollutants in coating processes also focus on benzene, benzene series and non methane total hydrocarbons as of March 2017. Some local standards also list other solvents commonly used in coatings, such as db33/(Zhejiang Province) and acetic esters, styrene, etc. However, no matter which standard, it is obviously not (or impossible) to list all volatile organic compounds commonly used or available for coatings in the emission limitation standard

however, is it possible to pass the environmental protection standard without benzene homologues in the paint? Obviously not

why do you say so? Because:

1. There are many volatile organic compounds available in paint, and new varieties are constantly invented or discovered and used in paint; Click reference to read: (including but not limited to) organic solvents commonly used in paint and coating

2. The current emission standards do not or cannot include all volatile organic compounds that may be used in paint

3. Although benzene and its homologues are highlighted in the emission limitation standard, it may only be because they are more commonly used and well-known, which does not mean that all benzene homologues have the worst environmental protection or the greatest toxicity compared with all other volatile organic compounds, nor does it mean that the problem often occurs that other volatile organic compounds are not limited in the design stage

4. As other volatile organic compounds belong to "non methane total hydrocarbons" and are subject to emission restrictions, it can be seen from the above figure that the pit for the emission of other volatile organic compounds after the removal of benzene homologues is not large (60/=19/39)

therefore, I believe that the use of paint without benzene homologues alone cannot guarantee environmental protection. If effective VOC treatment and emission measures are not taken, that is, there are only a few unqualified items on the machined surface of the experimental machine parts in pollutant emission monitoring data 4, and the emission of "non methane total hydrocarbons" cannot be qualified

coating application units should adopt effective coating waste gas treatment process by using water-based, solvent-free, high solid coating as much as possible, adopting more environmentally friendly coating process (reducing the use of diluents), so as to ensure up to standard emission, rather than using this opportunistic means

some new solvent manufacturers should not vigorously promote them as environmentally friendly solvents because they are not separately listed in the emission limitation standards, and when their environmental and health hazards are not clear (Note: it takes a long process for human beings to recognize the environmental and health hazards of a chemical) (Note: this situation was common in previous industry conferences)

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