More and more frequently, in recent times, we have been contacted by companies and enterprises in the industrial sector who ask us for products (detergents and above all solvents) to reduce their VOC emissions following visits by competent bodies (see ARPA, acronym of agency Regional Authority for Environmental Protection).
In this regard, we want to firmly reaffirm the concept that eliminating VOC emitting solvents and detergents from industrial manufacturing processes is possible and is not a utopia.
However, before thinking about our products, it is necessary to take a step back and understand the meaning of “VOC”.
VOC is the acronym of volatile organic compound where organic compound means any compound containing at least the element carbon (C) and one or more of the elements hydrogen (H), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), iodine (I), sulfur (S), phosphorus (P), silicon (Si) or nitrogen (N), with the exception of carbon oxides (e.g. CO2) and carbonates and inorganic bicarbonates.
We are talking about substances based on carbon chemistry, i.e. organic chemistry.
A VOC, according to paragraph 11 of article 268 of Legislative Decree 152/2006, is any organic compound which, at a temperature of 293.15 K, or 20 °C, has a vapor pressure of 0.01 kPa , or higher, or which has the corresponding volatility under particular conditions of use. Vapor pressure and volatility define the ability of a substance, solid or liquid, to pass into the gaseous state.
In other words, more empirically, by leaving a tank containing a pure organic substance of interest in contact with the atmosphere (at 20°C), the substance is defined as VOC if a concentration higher than about 100 ppm is measured in the gas phase.
Volatile organic compounds, as can be seen from the previous definitions, are a family of different chemical compounds, which, among other characteristics, also have that of being able to react, when dispersed in the troposphere, giving life to polluting compounds.
The following are part of this class of organic compounds:
- aliphatic hydrocarbons (e.g. butane, propane, n-hexane)
- aromatic hydrocarbons (e.g. benzene, toluene)
- halogen derivatives (e.g. dichloromethane)
- aldehydes (e.g. formaldehyde)
- ketones (e.g. acetone, MEK)
- alcohols (e.g. ethanol, butanol)
- esters (e.g. ethyl acetate)
- other compounds (e.g. acetic acid, acrylamide, nicotine, acetonitrile)
On a general level, it is possible to state that each air pollutant has a characteristic residence time in the atmosphere, linked to its chemical-physical properties. The greater this time, the more the pollutant can be dispersed into the atmosphere by winds and currents, altering the chemical balance of the atmosphere itself.
Many VOCs intervene, for example, in the balance of methane (CH4), prolonging its permanence in the atmosphere and thus contributing to the increase in the greenhouse effect.
It is also important to note that many VOCs are dangerous to humans and animals. By way of example, by no means exhaustive:
- Benzene is a carcinogenic compound characterized by high volatility.
- Formaldehyde is another toxic compound produced in large quantities and commonly used in many production processes.
- Halogenated compounds have high volatility and toxicity characteristics; moreover, being basically hydrophobic, they can accumulate in the body.
- Organic sulfur compounds have a marked tendency to have a nauseating and unpleasant odour.
How to intervene to reduce VOCs?
To answer this question it is necessary to take into account the flammability potential of these substances.
Sometimes, if not often, it is necessary to design ATEX systems in order to reduce and manage the risks of fire and/or explosion associated with the presence of VOCs.
Taking these aspects into consideration, we can intervene with the installation of special vapor filtration systems such as:
- active carbon filters
- scrubber towers based on wet filtration
All these types of installations are expensive and require constant maintenance, while replacing VOC-emitting solvents with solvents or cleaners without or with reduced emissions is more practical, advantageous and economical.
Thanks to their characteristic of non or low volatility, this new type of solvent is recyclable by decantation, and in addition significantly reduces (minimum 3 times) the volume of losses due to evaporation.
In other cases, where possible, we can replace the VOC-emitting solvents with specific detergents, specially developed for minimal or even zero environmental impact.
Purmate can propose various solutions in this regard, guiding the customer in making the best choice from an operational/practical, economic and health and environmental protection point of view.
Below is a table with the comparison parameters between acetone and some of our products; let’s take as an example the cleaning process of unpolymerized resins and glues of different nature (polyurethane, epoxy, polyester), and we could make the same comparison between other VOC emitting solvents and other “green” products for cleaning oils and greases from surfaces.
Not only do our products emit less VOCs, but they have a safer flash point, a key feature for handling and storage, and have a vapor pressure at 20°C that is significantly lower than acetone, which equates to a significant saving in produced by evaporative losses! Let us also not forget that some of our products allow the operator to work without a protective mask, if aerosols are not formed in the work area which cannot be expelled with adequate suction or the room is not adequately ventilated.
You have seen that there are different products of different nature that we can use to replace acetone; sometimes the replacement is simple, sometimes more complex and also determines a change in the way of operating, but the benefits are unquestionably greater than the disadvantages. The replacement of a solvent must be carefully weighted with a 360° evaluation. We say this because we know very well that alternative solvents and detergents cost more than traditional products, but if we go into a thorough analysis of all the costs we incur in using a VOC emitting product (management of use, storage, specific medical visits for exposed operators, disposal of hazardous waste which turns out to be toxic-harmful), you can realize that the gap between a “green” product and a “traditional” product is not so abysmal.
We think, “less pollution, more savings!”