The basis of centrifugal purification is the density difference between the fluid to be salvaged and the liquid or solid contaminants suspended (free or emulsified liquid contaminants) in the fluid. Specially designed centrifuges, combined with “extras” such as in-line filtration and vacuum dehydration units, allow for extremely efficient separation of some industrial fluids. Enhanced performance is achieved through features such as sludge-resistant and self-desludging systems, valves and piping, speed adjustment, adjustable phase separation (for oil/water separation), which provide the unit with versatility to purify oil for either sediment or oil/sediment removal.
There are various benefits associated with centrifugal purification of oil. They include cost-savings resulting from decreased oil usage, reduced disposal costs and waste elimination. Production improvements result from less downtime as the frequency of system drains and recharges are reduced. Environmental objectives such as QS 14001 can be positively impacted through oily waste reduction. Cleanliness levels exceeding that of replacement oil can be achieved, because system-wide contamination is removed as part of the remediation process. In many cases, oil can be purified to the most demanding cleanliness specifications.
There are many benefits to onsite versus offsite centrifugal remediation. Onsite remediation eliminates the legal liability of shipping oil offsite. In the case of emergencies, onsite purification ensures that real-time remediation can be done; the in-process nature of onsite remediation reduces or eliminates any negative impact on production.
Challenges complicating onsite remediation involve frequent system testing and monitoring and the ability to keep the centrifuges calibrated and running. These challenges can be overcome by using an oil purification service, which provides engineers and technicians to calibrate the purification system, test the fluids, and monitor the process from start to finish. The service should be able to provide analytical abilities specific to the fluid being remediated. For oils, this should minimally involve monitoring ppm water concentration and particle counting of solids according to ISO 4406.
There are several equipment choices to purify oil. Permanent or temporary system-mounted centrifuges can be used as well as mobile, truck or cart-based, units. For oils, equipment capabilities should include liquid/liquid and solid/liquid contamination removal, and the ability to provide dehydration and acid level reduction. Equipment might also include extras such as in-line polishing filters (to achieve ultra-fine sediment reduction) and in-line particle counters (to monitor ISO codes on a real-time basis). Mobile units might include a suction pump to pull oil from in-ground reservoirs without a separate pump, and the ability to operate either plant-supplied electric or on its own generator. All equipment must be sized properly to allow acceptable contamination removal within the required time period.
Centrifugal purification technology is suited for both large machining operations and small sump-side use, for emergency remediation as well as routine contaminant control assistance. A variety of industrial fluids, including straight oils and metalworking fluids, can be remediated with a specifically designed purification unit.
Transmission Plant Case Study
An automotive transmission plant, located in Michigan, was facing a potential production emergency. A 12,000-gallon centralized (cutting oil) system had been contaminated with almost 3 percent water. Production could not afford to stop the line, the oil supplier could not supply 12,000 gallons of broaching oil, and yet expensive tooling was being destroyed. The plant was in a dire situation.
An obvious solution was to drain, dry and recharge the system. This, however, would have necessitated a shutdown and a supplier change - neither of which was acceptable to plant management. The problem was solved using an onsite centrifugal purification service for oils.
The broaching oil was provided from a 12,000-gallon central filtration system located under the floor. Somehow, almost 350 gallons of water leaked into the system. When the oil purification service technicians arrived, the water level was 2.8 percent, and solid levels were 82 ppm.
A mobile reclamation unit was brought onsite to implement the water and sediment reduction plan, attaching to the plant’s electric system, and connected hoses in a kidney-loop configuration to pull oil directly out of and back into the central system.
The centrifuges were calibrated to remove the maximum amount of water with each pass. A removal efficiency of 98 percent water was achieved in a single pass. Progress was evident within a few hours. After 12 hours, the water level dropped from 2.8 percent to below 1 percent. The situation continued to improve hourly. Within the next two to three hours, the water level dropped below 0.5 percent. Within 22 hours, the water level had dropped to below 500 ppm.
Ensuring stable tool costs, reducing downtime for tool changes, and ensuring that production could continue. Production rates were able to resume to normal, acceptable levels. Savings included the cost of new broaching oil, new tooling, reduced downtime, and resumed production rates. The SRS emergency oil remediation service cost this company $0.80 per gallon, saving the customer $17,300 in oil costs alone.
Many of the problems associated with dirty or contaminated oil can be solved through onsite centrifugal purification to purify oil. In an emergency situation or as part of a routine, data-driven contaminant control program, this technology can positively impact production, quality, costs, waste disposal, and environmental issues for a manufacturing facility. In this case, the emergency oil remediation service saved $17,300 in oil costs, reduced downtime and saved tooling and allowed for continued production.