The oil and gas sector is heavily reliant on storage tanks and containers, from petroleum, crude and refinery oil tanks to gas stations and depots, all of which require ongoing maintenance to preserve structural integrity and extend operational life.
Research shows that most storage-tank failures in the oil and gas sector stem from incomplete or poorly executed inspection, maintenance, and repair activities, which leave tank owners unable to anticipate failures or implement effective preventive measures.
The consequences of a tank failure can be severe: leaks of highly flammable products create significant fire and explosion hazards, while spills into waterways can cause substantial social and environmental harm.
This is in addition to the substantial financial losses from lost hydrocarbons, damage to the tank itself, and the revenue impacts of having the asset out of service.
Petroleum tank cleaning removes the residual build-up of petroleum’s heavier components over time, which can take up tank space and reduce the asset’s effectiveness.
There are several methods for cleaning oil tanks, but any viable approach must prioritise worker wellbeing, cleaning effectiveness, time and cost efficiency, and environmental safety.
Moreover, waste minimisation and the rate of hydrocarbon recovered are becoming especially important in the context of sustainable operations.
In addition, the ability to reclaim hydrocarbons is financially critical to tank-cleaning operations, with recovered product helping to make automated cleaning a commercially viable option.
There are three main automated hydrocarbon management systems: Oreco’s BLABO system, Mirrico’s robotic MARTin system, and KMT International’s MegaMacs technology.
EPCM Holdings describes BLABO as a compact, portable system that eliminates the need for human entry and can extract nearly all hydrocarbons remaining in the sludge.
The process is closed-loop, with sludge at the bottom being dissolved, vacuumed, segregated, and released.
The MARTin system uses an autonomous clean-up method with external control, negating the need for workers inside the tank.
Instead, it has a remote-controlled robotic vehicle that enters the tank to break down and remove the sludge.
MegaMacs is an independently powered system housed in two transportable containers, capable of removing hydrocarbons from a range of sources and separating petroleum, water, and solid residues from sludge.
Uniquely, MegaMacs features an adaptable hydraulic framework that requires no specialised ground preparation and can be relocated by six workers and installed in roughly four hours.
A 2020 paper published in Processes reviewed five applied clean-up methods available on the world market – including manual, automatic, and robotic systems – to identify the most efficient, safe, economical, and environmentally friendly process.
The researchers concluded that the tank-cleaning sector has a strong need for high-efficiency automatic or robotic cleaning technologies.
They noted that these methods should “aim to reduce the tank downtime, without the need for staff entrance into a permit required confined space, and with the ability to recover up to 100 per cent of the hydrocarbons present in the composition of the sludge”.
Results of the study showed that the MegaMacs with the sludge extractor automatic cleaning system, with an output of 14.8 cubic metres an hour, was the fastest cleaning system.
The safest, on the other hand, was found to be the MARTIn system, which does not require people inside the tank at any stage.
Due to the closed cleaning circuit and the ability to recover up to 95 per cent of the oil from the sludge, the researchers found the automated BLABO, COW, and MEGAMACS systems, as well as the MARTIn robotic system, to be the most economic and environmentally friendly.
The researchers also highlighted an automated robotic calibration system developed by Saudi Aramco, designed to ensure accurate tank measurements, capture the true value of stored products, and improve safety by removing the need for operators to perform manual calibration at height.
As metal storage tanks expand beyond their initial capacity, continuous monitoring and calibration are needed to maintain accurate model predictions.
Called ‘autonomous robotic tank calibration’ (RTC), the invention was developed into an industrial product, tested and commercialised, and saw broader deployment to Aramco facilities.
RTC is comprised of a base station, which is placed on the lower level of a tank’s outer shell and includes a laser that points upward to a ‘crawler’, a robot that travels up along the full height of the tank in a straight line.
It then uses a digital ruler to measure the tank’s offset in microns – instead of millimetres – to capture diameter changes along the tank’s height with very high accuracy.
The ISO has also officially accepted and adopted Aramco’s robotic calibration solution.