Slop Oil Recovery. A Paying Proposition
Proper treatment can convert all kinds of slop oil from oil fields, refineries and industry into valuable, marketable products. What is often a serious pollution or storage problem can therefore be turned into clear profit. At the same time, expensive tank capacity or land area can be released for more profitable use.
A difficult separation problem.
Originating from many sources, slop oils vary widely in composition and physical properties. One common factor is that they contain both water and solid impurities, coarse as well as fine. Often the oil and water form a very tight emulsion.
Treatment of slop oils is therefore a tricky task and most of the methods used for their recovery fail in one way or the other. Gravity settling is a slow and often ineffective operation that requires plenty of space and often expensive chemicals. Filter presses can only separate solids from the liquid and have low capacity. Incineration is an expensive process, and the oil is not recovered.
Centrifugal separation - the key to successful recovery
Experience has shown that centrifugal separation in an Quantex centrifuge system is the most efficient and cost-effective method for slop oil treatment. This is the result of the special design features of the oil/water centrifuge employed and the high g-force it develops.
Depending on source and quality, each slop oil requires its own technical solution. A single centrifuge may suffice or a multi-stage system, including pond mobilization equipment, may be necessary. Based on precise laboratory testing, the systems supplied by Quantex are tailor-made for the optimal solution to each individual case.
Slop Oil. Tricky Stuff to Treat
A characteristic of slop oil is that the oil and water form an emulsion stabilized by ultrafine solids, difficult to separate even under normal conditions. A typical particle size distribution curve is given in the diagram to the right. High viscosity is also characteristic, as well as the fact that the composition of the slop oil fed to the treatment plant often varies greatly with time.
Thus, the first demand on a profitable slop oil recovery system is that it can efficiently separate three phases. The second is that it is effective enough to split the tightly bound emulsion and separate the finest of particles. And the third demand is that it can cope with widely varying feeds, and still do a good job.
The varying physical properties of slop oils also make them difficult to handle. Sometimes they pose an erosion or even a corrosion risk, which calls for experience and practical measures to combat. As well as being difficult to separate, some of them are also hard to mobilize, which demands its own technology.
Quantex has the know-how and resources
To sum up, slop oil is tricky stuff to treat, calling for in-depth knowledge and efficient process equipment. Quantex can offer both. We have the experience gained from from the extensive design and operation of a number of oil recovery systems and mobilization equipment for different types of slop oils.
The Quantex System for Profitable Processing
Normally a Quantex oil recovery system consists of the 2 or 3 phase centrifuge combined with pre-separation and heating equipment. The duty of the latter items is to condition the feed for the most efficient and reliable separation of oil, water and fines.
For very intractable slop oils Quantex has, based on practical experience, developed the system illustrated below. This system is the optimal solution to the treatment problem when the feedstock contains large amounts of solids and water and has a high viscosity.
In many cases, however, only parts of this system or even just a disc-stack or decanter centrifuge alone will do the job efficiently. To find out what is the solution with the greatest cost benefit for the customer a representative sample of the slop oil is evaluated by Quantex to determine the optimum treatment requirements.
Complete Recovery Systems
Once the slop oil has been analyzed, Quantex will review the work location, available utilities and customer requirements to determine the optimum treatment methodology and to ensure that any necessary disruptions to the clients ongoing operations are minimized. By maintaining maximum design flexibility, Quantex is able design a system that will require minimal mobilization and set up time.
For operation in isolated areas, Quantex will design complete self supporting oil recovery systems, including pond mobilization systems and utility supplies.
Key components of an optimal slop oil system
Individually designed as required.
Individually equipped as required. Mixers and heating coils are utilized when required. Free water drains and top outlets for oil are included on all tanks. In many instances the feed tank serves as a pre-separator, reducing the volume to be centrifuged and thus improving the efficiency of the setup.
An erosion-resistant design, specially selected for gentle handling of the product.
For removal of particles down to about 2 mm and also particles lighter than the liquid.
Chemical feed pump
When chemical addition is required, Quantex strives to design treatment methodologies that utilize the minimal amount of chemical addition.
For removal of sand and other particles down to about 100 µm, that can cause erosion downstream.
Two and three-phase decanters for separation of particles down to about 20 µm from the slop oils.
6. Intermediate tank and pump
Here the liquid is directly or indirectly heated by means of steam to approx 80 °C, in order to lower the viscosity for increased separability. The use of direct steam can in certain cases help to split emulsions.
Solids-ejecting disc-stack centrifuge
Capable of separation of oil, water and fine solids down to about 2 µm. Utilized when a BS&W of less than 2% is required.
A compact and efficient plate-type cooler for cooling of the oil to storage temperature (optional). Outgoing oil or water can preheat incoming oil by means of regenerative heat recovery.
QC System Optimization
When doing site work, Quantex maintains on site laboratory capabilities allowing us to continuously evaluate system performance and ensure quality of the recovered oil.
Heating and centrifugal separation
Our laboratory procedures actually simulates the processes in the full-scale Quantex system in that it utilizes centrifugal separation in combination with heating and any other steps that may be included. In contrast to methods employing solvents it accurately indicates what components of the slop oil are recoverable, and how much sludge there will be for the system to remove. In this way Quantex can continuously monitor the quality of the slop oil and make subtle changes to the process without affecting the efficiency of the recovery system or impacting the quality of the recovered oil.
The Economics of Slop Oil Recovery
Incineration or disposal of slop oil costs a lot of money. These costs are continuous - year in and year out, as long as there is slop oil to take care of.
Recovering the oil not only reduces the costs, but can also create a profit. How much profit will depend on the amount of recoverable oil, and the efficiency of the equipment used for the purpose.
A very high efficiency, as achieved by Quantex's treatment system, means that the recovered oil often pays for the investment costs very quickly. And pay-back time is shortened by low supervision and maintenance costs. The equipment is well-proven and reliable with a high degree of automation, ensuring good long-term profitability.
The example in the diagram below is taken from an actual pond oil recovery system, and illustrates a case when the oil recovered during the first year paid for the entire plant. It also shows the high percentage of oil that is recovered in a Quantex system.
Evaluation without obligation
With its own inhouse laboratories and testing equipment, Quantex can quickly predict the economics of slop oil recovery at the planning stage. So why not contact us find out what Quantex can do for you. Based on the analytical and test results, we can make an accurate calculation for your particular case. So, the question you should be asking is not how much a slop oil recovery system will cost, but how much it is costing you not to have one.
Acknowledging that different customers have different requirements and that the quality of slop oils may vary throughout a project, Quantex strives to incorporate the greatest amount of flexibility possible into the recovery process setup so that unforeseen circumstances will have minimal to no effect on the completion of the project.
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