Why Does the Performance of a Solvent Distillation Unit Deteriorate Over Time?

There are several common reasons solvent distillation units experience a decrease in performance. Explore a few of the most common problems and learn how you can mitigate them.

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Does your facility own a distillation unit for recycling the flammable solvents used in your processes? That’s fantastic if your facility does. It means you’re saving on solvent expenses, reducing hazardous waste disposal fees and being a good steward for the environment.

However, are you aware that the performance of the solvent distillation unit will deteriorate over time, ultimately costing you some of that savings?

Main Performance Problems on Solvent Distillation Units

Solvent distillation unit performance is affected by continued sludge buildup in the distillation vessel, long term lack of attention and electrical component obsolescence.

Like a car, and most critical equipment, an on-site solvent recovery system requires routine maintenance, daily, weekly, monthly, quarterly, and annually. Also like a car, the machine’s performance will be affected if some of the maintenance items are not addressed when required. Without proper maintenance performance issues can add up to additional expenses which may have been preventable.

Thermal Oil Heating Problems

A distillation unit requires a heating source strong enough to overcome the physical properties of the solvent to be distilled. The most common heating sources are electrically heated thermal oil or a steam jacket.

The thermal oil needs to be replaced annually at a minimum. Not replacing the thermal oil in a timely manner will lead to carbon buildup of the oil jacket.

The carbon builds up on both the jacket sidewalls and the heater elements. Buildup on the side walls acts as an insulator preventing efficient heat transfer. Buildup on the heating elements leads to heater failure.

Steam Heating Problems

A steam heated system must be treated with utmost care because it will degrade over time. Steam jackets are susceptible to calcium buildup if the water used in the process is not properly treated.

The valves and regulators used for adjusting steam pressure – steam pressure is the temperature control – require regular inspection and maintenance by specifically qualified personnel.

An inefficient heating system requires more energy to get up to proper temperature, adversely impacts the distillation output rate and lengthens the entire distillation process adding to utility costs and process delays.

Sludge Buildup on Heating Surfaces

A distillation unit will build up sludge on the heating surfaces with continual use. Sludge buildup on the heating surfaces reduces heating effectiveness, requiring more time to process the solvent and more energy to operate the system.

A machine without internal, rotating scraper blades requires daily cleaning of the heating surface, at least after every discharge.

A unit with rotating scraper blades will clean the heating surfaces but see sludge buildup on the non-heated surfaces not touched by the scraper blades.

Some scraper blades require manual adjustment to control the sludge buildup on the heated surfaces as well. Not ensuring the scraper blades are in contact with the heating surfaces will allow sludge to build up in those areas.

Sludge Buildup on Non-Heated Surfaces

Sludge buildup on the non-heated surfaces can lead to contamination of the distillate as particles from the sludge escape with the solvent vapors.

Scheduled cleaning of the vessel interior is required to prevent the buildup of contaminants on the non-heated surfaces and scraper blade components. This also allows for easier adjustment, or replacement, of scraper blades.

When easy access to the vessel interior is not afforded, a caustic cleaning solution aids in the removal of the sludge buildup by allowing it to stew. A distillation vessel with easier access can be manually scraped clean or cleaned with a pressure washer. All of this is extra labor hours.

Electrical Component Issues

Electrical component obsolescence is also a factor negatively affecting the distillation performance.

PLC’s, HMI’s, amplifiers, sensors and other devices are phased out over time by the manufacturers. Obsolete components are harder to source for replacement and are typically not supported by the manufacturer.

Sometimes, a one-to-one replacement is available. However, modifications are often required to accommodate direct replacement components.

PLC or HMI obsolescence can require all new software, or programs, to support the replacement device. If you decide to use non-supported devices they can degrade distillation performance when starting to fail with longer lead times while sourcing a replacement method or requiring process workarounds by the operators.

Unplanned Expenses Can Add Up

Prolonged use of an underperforming distillation unit impacts the entire operation.

Instead of recycling your solvent effectively, it causes more solvent to be sent off as waste and requires the purchase of more virgin solvent. Valuable operator time is required to focus on the distillation unit rather than other operational duties.

Increased maintenance time and labor is demanded in order to continue operation of the system. The decline in performance of a distillation unit directly impacts the overall cost of ownership. Over time, the distillation unit’s performance will decline for all or any number of the reasons described leading to value leakage.

Our Solution

Partnering with CleanPlanet’s Service365 program eliminates all of the frustrations and struggles associated with solvent recovery system ownership.

Like a car, failure to conduct preventive and routine maintenance will lead to long term, and potentially costly, performance issues. CleanPlanet’s Service365 removes these responsibilities from the end user.

CleanPlanet maintains responsibility for the performance and maintenance of the equipment including all component and system upgrades, eliminating the concerns of solvent recovery system performance degradation.

This leaves you with a high performing distillation unit that will save you money on solvent month after month without the costs of maintenance and repair. If you’re ready to start saving contact our team or take a look at the details on our Service365 program.


CleanPlanet partners with its customers to ensure they are maximizing their solvent recovery yield. Our Athena system delivers reliable metrics you can see at any time to monitor your solvent distillation units health and quickly identify any potential issues. If you’re struggling with an underperforming distillation unit reach out to our team to see how we can help.


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