Heavy Fuel Oil (HFO) Treatment
What is HFO
Heavy fuel oil is the residual fraction remaining after the lighter products have been distilled from crude oil. It is burned in marine main and auxiliary engines, industrial boilers and power generation sets. Its advantage over distillate fuels is cost per unit of energy, and that advantage holds only while the fuel arriving at the injection equipment is clean. PuraSpecs supplies the separators and treatment systems that keep it clean.
Treatment Duty
| Parameter | Detail |
|---|---|
| Feed | Heavy fuel oil, residual grade |
| Contaminants removed | Water, catalyst fines, sludge and sediment |
| Separation principle | Centrifugal, acting on the density difference between phases |
| Configuration | Purifier or clarifier, selected on the water content of the feed |
| Discharge | Continuous, no batch settling time required |
| Construction | Skid mounted, fixed installation or mobile package |
| Commercial | Purchase or rental, with operation on site where required |
Contaminants and Their Effect
| Contaminant | Origin | Effect if untreated |
|---|---|---|
| Water | Condensation in storage, leaking heating coils, bunkering | Salt carryover into the engine, corrosion of the fuel system, microbial growth in the tank bottom |
| Catalyst fines | Carryover of aluminium and silicon oxide from the refinery fluid catalytic cracking unit | Abrasive wear in fuel pumps, injectors and cylinder liners |
| Sludge and sediment | Asphaltene precipitation, blending of incompatible fuels, settling during storage | Loss of usable tank capacity, blocked filters, fouled heating surfaces |
The same separation duty occurs in adjacent streams. For water in the crude itself see crude oil dehydration. For solids already settled in the tank bottom see tank sludge removal and cleaning.
Treatment Approach
Purification of heavy fuel oil is carried out by centrifugal separation. The fuel enters a separator bowl running at high rotational speed, where centrifugal force acts on the density difference between the oil phase, the water phase and the solid particles. Water and solids are discharged continuously while the purified fuel passes forward, so the duty is performed in continuous operation and no batch settling time is required. The separator is supplied as a complete skid mounted unit, either as a fixed installation or as a mobile package.
Separator Configuration
| Configuration | Use when | Removes |
|---|---|---|
| Purifier | Free water is present in the feed | Water and solids, with a water seal established in the bowl |
| Clarifier | Free water has already been removed upstream | Solids only |
Operating notes
- The fuel is preheated ahead of the separator so that viscosity falls and the density difference between phases can be exploited.
- Feed rate is set below the hydraulic capacity of the bowl, because residence time in the separation zone governs the smallest particle that can be removed.
- Where a single pass does not reach the required cleanliness, separators are arranged in series or the fuel is recirculated through the treatment loop.
- Separated water and sludge leave as an oily waste stream, itself treatable: see slop oil treatment and contaminated water treatment.
Scope of Supply
Separators and treatment systems for continuous duty on heavy fuel oil. The equipment is selected according to the contaminant load, the required throughput and the fuel specification of the application, so that the configuration corresponds to the duty it has to hold.
Rental units in several sizes for short and medium term projects. The packages are skid mounted and transportable to site. An experienced operator can be supplied with the unit so that it is integrated into the project without additional personnel. Ask for current rental availability.
Operators run the separators and treatment systems on site. Technicians carry out installation, commissioning, maintenance and fault finding, so that the system is held at its design performance and interruption to the process is limited.
PuraSpecs is the mechanical systems engineering arm of SorbiTech Group. The fabrication workshops operate under an ISO 9001:2015 system tailored to fabrication, covering weld procedure qualification, welder qualification and inspection and test plan controls. Engineering, fabrication and delivery therefore remain under single accountability.
Related Services
Heavy fuel oil treatment is supported by the following PuraSpecs services. The full range is listed under services.
Oily Sludge Treatment
Efficient and sustainable oily sludge treatment for ponds and lakes, using horizontal decanter technology to separate oil, water and solids so recovered oil can be resold.
Oil Contaminated Soil Remediation
Integrated wash and separation technology that tackles oil contamination in soil, cutting the environmental risk it poses to surrounding land and industry.
Contaminated Water Treatment
Separators and decanters that combine centrifugal force and gravity to strip solid particles, sediments and oils from water, without chemical intensive methods.
Tank Sludge Removal and Cleaning
Removal of accumulated sediment and contaminants from storage tanks, to prevent equipment damage, maintain product quality and stay within environmental regulations.
Engineering FAQ
What does heavy fuel oil treatment remove?
Water, catalyst fines, sludge and sediment. These are the contaminants that would otherwise reach the injection equipment, where they cause wear.
Is a purifier or a clarifier used?
The configuration is selected on the water content of the feed. A purifier suits a feed carrying free water, a clarifier is used where the duty is principally solids removal.
Does the separator stop to discharge?
No. Discharge is continuous, so there is no batch settling time and the fuel supply to the engine or boiler is not interrupted.
Talk to an Engineer
Send the fuel analysis, the required throughput and the site conditions. We will return a recommended configuration and a scope of supply. For the adjacent treatment duties see applications.