The present invention relates to a method and a system for purification of oil.
Purification of oils, such as for example slop oil, waste oil and industrial oil is important for the possibility to reuse oils and therefore an important factor for the environmental future and the limited nature resources of oils. Purification of slop oil is problematic in many ways. Slop oil can comprise oil, water, particles and emulsion phase. The particles can stabilize the emulsion phase and complicate a purification process. Purification of industrial emulsions comprising water and oil, such as for example cutting fluids is also an important environmental issue.
An object of the present invention is to improve efficiency in purification of oils.
This is achieved by a method for purification of oil comprising the steps of:
This is also achieved by a system for purification of oil, said system comprising:
Hereby content on its way from a preparation tank to a next step in the purification process can be automatically redirected to another destination if a sensor indicates that the content is not suitable for the next purification step. This could for example be if a phase of water is transferred out from the preparation tank. In that case it would be better to redirect the water phase to another destination and not provide it into for example a centrifugal separator.
In one embodiment of the invention the method further comprises controlling said valve to only transfer the content to the next step of the purification process if the sensed property corresponds to an oil content above a predefined threshold.
Hereby content comprising a low percentage of oil can be redirected to another destination possibly for further purification by other means.
In one embodiment of the invention the method further comprises controlling said valve to not transfer the content to the next step of the purification process if the sensed property indicates that the content is water. Hereby water can be redirected to another destination.
In one embodiment of the invention the step of sensing comprises sensing dielectric properties of the content. A sensor detecting dielectric properties is robust also in harsh environments.
Further embodiments are described in the detailed description and in the dependent claims.
The oil purification system comprises further a centrifugal separator 7. This can be a centrifugal separator which is adapted for separating out water and/or sludge from oil which is useful for the purification of slop oils. The centrifugal separator can also be a decanter centrifuge adapted for separating particles and sludge from oil and water. Such a centrifuge can be used in a step of purification before the use of another centrifugal separator when slop oils are purified. Another type of centrifugal separator which can be used in this invention is adapted for separating oil and sludge from water which is useful in the purification of industrial emulsions, such as cutting fluids and oil contaminated water. In a process and system for purification of lubrication oils and/or industrial oils according to the invention a centrifugal separator 7 designed for separating impurities from the oil is used.
The oil purification system comprises further a fluid connection 9 allowing transfer of content out from the preparation tank 5. According to the invention a redirection arrangement 10 is provided in the fluid connection 9. The redirection arrangement comprises at least one sensor 11 provided in the fluid connection 9 and a valve 13 arranged in the fluid connection 9 to direct the content from the preparation tank 5 to either the centrifugal separator 7 or to another destination. The other destination could be another part of the system such as for example a storage tank 15 or back to the preparation tank 5, shown as an alternative with a dotted line 15′ in
The at least one sensor 11 is arranged to sense a property of the content passing the sensor in the fluid connection 9. The property sensed can be for example dielectric properties of the content. Such a sensor can be based on capacitive or microwave measurement technology or based on impedance spectroscopy. An advantage with this type of sensor is that it is a very stable type of sensor which is not affected by the environment. For example if impurities from the oil will be attached to the sensor the output from the sensor will not be affected as would be the case with many other types of sensors. This is especially useful when purifying slop oils because of the many impurities that can be present in slop oil. When slop oils are purified different phases comprising for example oil or water may be built up already in the preparation tank. According to the invention a phase of for example water can be redirected to for example a storage tank 15 by the redirection arrangement 10 instead of entering the centrifugal separator. For slop oil purification a sensor setup which can differentiate between oil and water can suitably be used. One possibility is to use at least one sensor measuring dielectric properties as described above. Possibly two such sensors can be combined where one of the sensors is tuned for giving a response for lower dielectric values than the other. Hereby the tuning can be set such that one of the sensors give a response when water is present and the other gives a response when oil is present.
When none of them gives a response air is present. The possibility to also detect air in the system is suitable and can be used for controlling of flows in the system. When water is detected the valve should in that case be controlled to transfer the content to the other destination, possibly the storage tank 15. When oil is detected or alternatively depending on sensor settings, when water is not detected the valve should be controlled to transfer the content to the centrifugal separator 7.
In purification systems which are arranged for purification of industrial oils or industrial emulsions where there are not as much impurities as in slop oils other types of sensors can be used instead. One example of a sensor which can be used is a sensor measuring density differences for example via a vibrating fork or Coriolis measurements. The control system 17 can be arranged to control said valve 13 to only transfer the content to the centrifugal separator 7 if the detected property corresponds to an oil content above a predefined threshold. Hereby impurities, water and sludge and oil containing more than a certain degree of impurities can be transferred to the other destination, possibly the storage tank 15, and not to the centrifugal separator 7. The content in the storage tank 15 could be transferred to another part of the system for further purification.
In one embodiment of the invention the step of controlling comprises controlling said valve 13 to only transfer the content to the next step of the purification process if the sensed property corresponds to an oil content above a predefined threshold.
In one embodiment of the invention the step of controlling comprises controlling said valve to not transfer the content to the next step of the purification process if the sensed property indicates that the content is water.
In one embodiment of the invention the step of sensing comprises sensing dielectric differences in the content or measuring density differences.
In one embodiment of the invention a step of warming the content in the preparation tank before it is pumped out is provided.
The system for purification of oil according to the invention further comprises a control system which is configured for controlling the system for purification of oil to perform the method according to the invention as described above. The control system is connected to pumps, valves and sensors in the purification system in order for controlling the flows in the system. The invention further comprises a computer program product comprising instructions which, when executed in a processor in the control system in the system for purification of oil of the invention, cause the control system to perform the method as described above.
Number | Date | Country | Kind |
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1650628-9 | May 2016 | SE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/SE2017/050453 | 5/8/2017 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2017/196233 | 11/16/2017 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3565252 | Sheehy | Feb 1971 | A |
3878094 | Conley | Apr 1975 | A |
4018683 | Walters | Apr 1977 | A |
4973299 | Rubin | Nov 1990 | A |
5570744 | Weingarten et al. | Nov 1996 | A |
5996690 | Shaw | Dec 1999 | A |
6214236 | Scalliet | Apr 2001 | B1 |
20030136747 | Wood | Jul 2003 | A1 |
20040244983 | Appleford | Dec 2004 | A1 |
20080288181 | Lucero | Nov 2008 | A1 |
20110283809 | Pihlaja | Nov 2011 | A1 |
20120152121 | Sampath | Jun 2012 | A1 |
20120160660 | Karlstrom | Jun 2012 | A1 |
20130026082 | Al-Shafei et al. | Jan 2013 | A1 |
20130082010 | Al-Mulhim | Apr 2013 | A1 |
20140077825 | Coleman | Mar 2014 | A1 |
20140083950 | Usher | Mar 2014 | A1 |
20140183058 | Wiemers | Jul 2014 | A1 |
20150307810 | Stigsson | Oct 2015 | A1 |
20160207791 | Rabe | Jul 2016 | A1 |
20170160069 | Folgero | Jun 2017 | A1 |
20180305604 | Breedlove | Oct 2018 | A1 |
20190192996 | Persson | Jun 2019 | A1 |
20200230520 | Sundström | Jul 2020 | A1 |
Number | Date | Country |
---|---|---|
2597344 | Feb 2008 | CA |
102989200 | Mar 2013 | CN |
103127746 | Oct 2014 | CN |
S55-28747 | Feb 1980 | JP |
S59-112808 | Jun 1984 | JP |
H1-275692 | Nov 1989 | JP |
2005-046657 | Feb 2005 | JP |
2012-245459 | Dec 2012 | JP |
0071640 | Nov 2000 | WO |
WO-2010111291 | Sep 2010 | WO |
2013049271 | Apr 2013 | WO |
2015026722 | Feb 2015 | WO |
WO-2016002110 | Jan 2016 | WO |
Entry |
---|
Donald L. Robinson, Chemistry 102—Recrystallization and Extractions of Organic Compounds, https://home.miracosta.edu/dlr/102exp3.htm (2009) (Year: 2009). |
Number | Date | Country | |
---|---|---|---|
20190192996 A1 | Jun 2019 | US |