Understanding Diesel Gelling

Diesel gelling is a cold-weather phenomenon where diesel fuel begins to solidify, impeding proper flow. Unlike water, diesel doesn't freeze at a specific temperature; it clouds as wax crystals form within. These crystals thicken the diesel, eventually leading to the gelling that can clog fuel filters and injectors, thereby straining fuel systems and engines.

Winter Grade Diesel: A Proactive Solution

Preventing diesel gelling starts with understanding the fuel itself. Winter-grade diesel is infused with specialised additives that prevent wax crystal formation. These additives keep the diesel fluid and pumpable even in lower temperatures, effectively addressing the root cause of gelling.

In South Africa, winter-grade diesel is distributed from 1 April to 30 September, aligning with the coldest months. It is vital to transition to winter-grade diesel timely, ensuring summer stock levels are minimised before the winter fuel is introduced.

Strategic Storage and Management

1. Storage Solutions

Large-volume storage tanks should be installed underground or in a wind-sheltered position to maintain a stable temperature. Before winter sets in, a thorough check and cleaning of tanks are imperative to remove sludge and moisture, which can exacerbate gelling. Keeping tanks near full capacity reduces 'breathing', where temperature fluctuations cause moisture and contaminants to be drawn into the tank.

2. Avoiding Cross-season Contamination

Ensure that summer-grade diesel is depleted before introducing winter diesel. When multiple tanks are in use, rotate them instead of designating any as a reserve. This strategy prevents the carry-over of summer diesel, which is more prone to gelling at higher temperatures than its winter counterpart.

3. Vehicle Vigilance

Parking vehicles in sheltered areas overnight can significantly reduce the risk of gelling. Keep fuel tanks full, as larger volumes resist temperature-induced gelling. Refuelling in warmer areas followed by travel to colder regions should be avoided. Instead, refuel in the cold region where the vehicle will operate.

In extreme conditions, delay departures until temperatures rise. If a vehicle does start but performs poorly, let it idle to warm the fuel system. Clean fuel filters are crucial; dirty filters are more prone to blockages by wax crystals.

The Role of Fuel Quality

The transition to Low Sulphur Diesel (LSD), which has a higher paraffinic content, has shown improved cold flow properties. LSD typically exhibits Cold Filter Plugging Point (CFPP) values well below -4°C, significantly reducing gelling risks. However, not all diesel is created equal, and quality varies. It is vital to source diesel from reputable suppliers that guarantee winter-grade fuel's protective properties.

Best Practices for Diesel Gelling Prevention

• Monitor the diesel fuel's CFPP value, ensuring it aligns with the expected lowest ambient temperature.
• Utilise fuel additives designed for winter conditions if the standard winter-grade diesel does not meet specific operational needs.
• Implement regular maintenance schedules for all diesel storage and dispensing equipment.
• Educate personnel on the signs of diesel gelling and the steps to take should they encounter gelling-related issues.

Responding to Gelling Issues

If gelling occurs, immediate action is necessary to mitigate its impact. Avoid using open flames to thaw diesel equipment; instead, employ safe heating methods like tank warmers or heated fuel lines. Contact technical teams with broad industry experience in dealing with such issues for guidance on resolving the problem and preventing future occurrences.

An Overview of Winter Diesel Gelling

As winter approaches, the onus is on industry professionals to proactively mitigate diesel gelling risks. By understanding the nature of the fuel, strategically managing storage, and utilising quality winter-grade diesel, the challenges of cold weather can be navigated successfully. Remember, vigilance and preparedness are the stalwarts against the cold-induced quirks of diesel.

For further assistance and in-depth technical support, reach out to Astron Energy's expert teams who are adept at ensuring your operations remain fluid, regardless of the temperature outside.