Editorial - Recover more oil, generate higher revenue | Alfa Laval

Recover more oil, generate higher revenue

Oil loss in effluent is one of the challenges that most of palm oil mills are facing. The average oil loss is typically high between 0.8% and 1.5%. This creates oil recovery opportunity to improve the revenue of the miller particularly when crude palm oil is currently at record high level.

DATE 2022-04-01

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Other challenges include the low quality and value of recovered sludge oil from pond, the lack of final oil recovery mechanism in the market to prevent oil spillage, and the fluctuation of the efficiency of oil recovery in the final de-oiling tank.

Alfa Laval’s latest technology – Final Oil Recovery Module – is every palm oil mill’s answer to recovering more oil from their mills and increasing profitability. This system uses heat transfer and separation technology to improve your yield and profitability by reducing the total oil loss in your palm oil mill from the average of 1.0% to 0.5-0.6%.


Potential of oil recovery in palm oil mills

Table 1 above shows the total oil loss from a palm oil mill, which is 1.77% (on FFB). There are four areas where oil recovery is possible, namely “Oil absorbed on the surface of EFB” (0.45%), “Condensate from sterilisation” (0.10%), “Sludge from separator” (0.45%), and oil spillages from leaking pipes or washing from tanks (0.10%). When we add all these together, we are looking at possibly up to 1.0% (on FFB) of potential oil recovery!   

Key technologies that enable efficient oil recovery

To recover oil, this system uses heat treatment to heat up the sludge to enhance the breaking of the emulsion and the high G-force will effectively recover small droplets of oil.

 

The complete process of the Final Oil Recovery Module

The block diagram above shows the process in a typical oil mill, where the block on the left is an oil room that houses the steriliser condensate, EFB liquor, decanter/separator/sludge centrifuge, hydro-cyclone wastewater, and a sludge pit. From here, the wastewater will normally go straight into a cooling pond in the right block. Alfa Laval’s Final Oil Recovery Module is an additional process that will be set up between these two blocks.

 

The diagram above shows the set-up of a Final Oil Recovery Module. The feed, which is typically 1% oil loss will enter a vibrating screen, where it will be cleaned to ensure there’s no impurities that block the equipment downstream. After that, it will be heated up to 90 degrees via Alfa Laval heat exchanger to achieve a good separation and recovery, as well as to break up the emulsion.

After screening and heating, the sludge will go into a retention tank, which acts as a buffer for the separator, followed by the high speed separator, which will separate or recover the oil from the sludge and wastewater and improve oil recovery from 1.0% oil loss to around 0.5 – 0.65%.

The recovered oil will then be stored in a Skimmed Oil Tank, and can be further treated with a Vacuum Dryer (optional). In the end, we will have oil with a purity of up to 99%.

The recovered oil will then go back to the mill. The discharged wastewater, which is cleaner now, will go into a cooling pond, followed by anaerobic treatment, and other palm oil mill effluent treatments, namely facultative treatment and aerobic treatment. You can also choose to do an evaporator – POMEVap, which will further enhance a mill’s footprint by going for Zero Liquid Discharge.     

Efficient oil separation with specially designed SX710+

The SX710+ is our specially designed upgraded separator to enable better oil recovery. It has higher G-force to improve the circling velocity of the oil to recover it, and a variable-frequency drive (VFD) to run the separator to reduce power consumption. In addition, it also has a vibration monitoring system to keep the machine in good working condition and to be more long-lasting.

The SX710+ is designed to include wear and tear protection to handle erosion. Its distributor insert and distributor tubes are made from a very hard wear-resistant material called stellite, while the distributor liner is made from a thick chrome stainless steel, measuring about 5 mm, which is strong and durable.

The bowl liner is also made from chrome stainless steel to increase its wear protection. And finally its nozzles, where sludge is discharged, are made from tungsten carbide, to enhance its durability and the performance of the machine.

The separator can be set-up in a skid unit and in a containerised execution so that it’s easy to install and move around. There will be typically two containers – one container with the separator and another with the tanks, such as the heat tank, along with the control panel inside the skid, which will control the operations of the system.

The skid will also consist of the control system, which controls the separators, including the BFD and all the pumps. Our skid is modularised into three set-up – ALFORM-45 (45m3/hour), ALFORM-30 (30m3/hour) and ALFORM-15 (15m3/hour).

 

Improve performance and boost profitability

After carrying out a few trials of this system in a mill in Sabah, we have successfully recovered oil loss down to 0.48% (on sample) with respective improved oil extraction rate (OER) of 0.31%.

An average OER improvement of 0.3% would translate to a 3.6 tonne of additional CPO per day for a 60 tonne FFB per hour mill. If we assume that the mill operates 20 hours per day and the price of oil is USD850 per tonne, this system will typically help the mill to recover up to USD918,000 per year! This amount is more than enough to pay for the investment in the ALFORM module. And based on this calculation, the payback is typically 1-2 year, including maintenance cost.

In brief, this system is simple and efficient, and it’s plug and play, which means it has small footprint, and easy to move around and maintain. It can recover oil at high purity, and its oil recovery is quantifiable, with flowmeter to measure the amount of oil that has been recovered every day. It also offers fast payback of less than a year, with a maximum of one year. And last but not least, this Final Oil Recovery Module will act as a final gatekeeper to prevent any oil from going down to the effluent pond.

A webinar on Alfa Laval’s Final Oil Recovery Module

This webinar demonstrates how you can take the oil loss in effluent to the next low level down to 0.5-0.6% and how you can control the Particulate Matter in emissions with a simple and cost effective solution.


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