There is an increasing number of businesses looking to become more environmentally responsible every day. According to a global survey by Tandberg cited in Environmental Leader, 53% of global consumers prefer to buy from companies that have a strong environmental reputation, and 8 out of 10 employees prefer to work for an environmentally ethical organization
“The findings clearly suggest a relationship between a company’s environmental reputation and its brand value,” said Tandberg CEO, Fredrik Halvorsen. “In addition to the ethical reasons for ‘going green’, there is a tremendous incentive for companies across the globe to focus efforts on environmental responsibility to attract customers, recruit and retain strong talent, and positively affect their external brand perception.”
One of the ways Temarry helps our customers be more environmentally responsible is by receiving their solvents and recycling them for reuse through a process called solvent distillation.
What Is A Solvent?
A solvent is a molecule that has the ability to dissolve other molecules, known as solutes. A solvent can be solid, liquid or gas. The molecules of the solvent work to put the solute molecules apart. Eventually, the molecules of solute become evenly distributed in throughout the solvent. This homogenous mixture is perfectly even, and cannot be separated physically. Heat or another chemical process must be applied to the solution to separate the solvent and solute.
Perhaps the most common solvent in everyday life is water. Many other solvents are organic compounds, such as benzene, tetrachloroethylene, or turpentine.
What is Solvent Distillation?
It is defined as:
“A process in which a liquid or vapor mixture of two or more substances is separated into its component fractions of desired purity, by the application and removal of heat”.
Solvent Distillation Recovery is based on the fact that the vapor of a boiling mixture will be richer in low boil point components such as acetones, ketones, aliphatic hydrocarbons and alcohols.
When vapor is cooled and condensed, the liquid condensate becomes a valuable product that can be sold back into the industrial market place. The higher boiling point portion of the original mixture that does not vaporize remains in the bottom of the recovery still. This portion is valuable as a fuel source for certain industries like cement kilns to recover the heat value.
Solvent recycling is preferred to other disposal methods for minimizing adverse environmental effects. Distillation is the most common method of solvent recycling, although filtration can be used to remove solids and non-mixable liquids.
You can learn more about solvent distillation and the energy recovery process in our previous article.
What Types Of Solvents Can Be Recycled?
Many solvents can be recycled, reprocessed, and then reused. The most commonly recycled solvents are:
- Mineral Spirits
- Halogenated Hydrocarbons
- Methylene Chloride
- 1,1,1 Trichloroethane
- Isobutyl Alcohol
- Isopropyl Alcohol
- N-Butyl Alcohol
- Methyl Isobutyl Ketone
- Methyl Ethyl Ketone
- Ethyl Acetate
On average, for every 100 drums of solvent that Temarry receives 70 drums of usable product are produced and sold back into industry. The remaining 30 drums of still bottom waste are blended to be used as fuel at a cement kiln. The result is that 100% of solvents that Temarry receives are recycled.
Because energy in the form of steam is produced from an onsite Waste to Energy process, Temarry is the only Closed Loop Recycling facility serving the western U.S.
Do Different Waste Solvents Need To Be Stored Separately?
There is no benefit for the generator to store or accumulate solvents separately. Often times solvent products purchased are a blend of different solvents listed above. For example, Paint Thinner can be a blend of aliphatic, aromatics, alcohols and ketones in various percentages. If a generator has various flammable solvents used in different processes they can be kept separate or accumulated together in the same container. It makes no difference in the solvent recovery process.
Should You Perform Your Own Solvent Recycling?
How hard can it actually be if you’re only boiling off liquids? Apart from all the federal and state environmental regulations, permits and approval processes your business would need to wade through, the cost of purchasing and operating a recovery still, would more than likely, be cost prohibitive.
If you are considering doing your own solvent recycling, here are a few items to consider when making a potential capital investment.
Initial Capital Investment
- Equipment Cost
Annual Operating Expenditures
- Cooling Water
- Costs of Manifesting left over waste products
All of these costs may be achievable for your business, however, you also need to consider your own State's regulatory guidelines for operating a recovery still.
Using it becomes the issue.
A small recovery still with a 10 to 20-gallon capacity is exempt from most permits for onsite use only. You will have to know and understand the requirements of state, county, city and fire districts for their location. That can be very cumbersome.
With the current environmental climate the way it is, it makes more sense these days to use facilities that specialize in the solvent distillation process, have already gone through all the bureaucratic red tape and are experts in transporting and disposing of your waste. It’s not just a good financial decision, it is a good business decision.