Unplanned downtime due to power outages can cost your business thousands of dollars, if not more. Businesses, educational institutions, hospitals, and residential complexes are investing in power backup. This is a huge step towards enjoying uninterrupted power even when the primary source is disconnected.

This blog explains the diesel generator fuel polishing process, its benefits and how it improves the shelf life of your diesel generator.

What is fuel polishing?

Fuel polishing is a technical process used to clean hydrocarbon and oil fuels that remain in storage tanks for future use. The stored diesel fuel undergoes a filtration process where contaminants are removed without fuel additives.

Contaminants can include sediment, microbial growth, and bacteria whose presence reduces the efficiency of generators.

The fuel polishing process also helps reduce the potential build-up of sludge, which typically occurs at the bottom of diesel fuel tanks.

What is a fuel polishing system?

A fuel polishing system is a device that uses a combination of a fuel filtration system to clean the fuel. Some generators are equipped with a fuel polishing system petrol generator manufacturer. When this happens, fuel polishing can be done without needing an outside fuel polishing service.

If a generator does not have its fuel polisher, an engineer can be deployed from a generator maintenance service provider that offers a fuel polishing service.

Today, industrial mass backup power systems come with connected fuel polishing systems, which can operate automatically. The flow rate can be 25,000 liters of fuel polished within an hour.

Fuel polishing is an essential part of diesel generator maintenance. It should be held at least once a year.

Why is diesel fuel required to be polished?

Generators use different types of fuel. People who use diesel fuel often need to store it for long periods. Fuel storage tanks can sometimes hold diesel fuel for up to ten years.

However, diesel fuel can begin to accumulate impurities within six months of storage. For example, it collects particles that turn into grease over time.

As diesel fuel is used, it can also draw foreign dirt into the tank. Dirt settles at the bottom of the tank. Therefore, diesel generators must have a diesel fuel polishing system.

Diesel fuel generators should have regular fuel quality tests followed by fuel polishing. Fuel polishing is crucial to this process, resulting in improved fuel quality and uninterrupted fuel supply.

Benefits of diesel generator fuel polishing

New diesel fuel should be bright pink and completely transparent. As the fuel ages and begins to degrade, the color darkens, and visible particles can be seen. 

Here are some of the benefits of diesel generator fuel polishing:

●    Improved system performance
●    Reduced wet stacking in diesel engines.
●    Environmental compliance
●    Less downtime
●    Increase equipment life and reliability

Impact on diesel fuel power backup

Fuel purity enables generators to operate efficiently by increasing the availability of fuel supplies. This process extends the time it can provide a backup power system during a power failure.

A reduction in fuel contamination enables the diesel generator to function correctly. This reduces the number of breakdowns and extends the shelf life of the generator by several years. This has a direct impact on cost savings.
There is no need to facilitate regular fuel changes, which comes at a cost.

Diesel fuel contamination

Generator engines can be used regularly and operated correctly and to specification. However, inside the fuel tank, out of sight, free and adsorbed water is gradually accumulating by condensation and even fuel delivery with high water absorption. As evening temperatures drop, water condenses out of the fuel and builds up inside the tank.

If water is on the bottom of the storage tank, the filter clogs bacteria colonies, and fungi will grow at the fuel/water interface. The product of these colonies is acidic sludge.

When the fuel/water interface becomes high enough to reach the engine's fuel supply tube, which may be inches above the bottom of the tank, microbes that clog the filter will be drawn into the fuel system and stop the engine.

99% of all fuel pollutants, Including water, are heavier than fuel and will be found at the bottom of the storage tank. Drain the water from the bottom of the tank, and the microorganisms will die.

It is, therefore, essential that the intake supply tubes of the fuel polishing system are located at the bottom of the storage tank. Failure to do so may result in an unexpected engine shutdown.

Microbes in diesel fuel

Virtually all diesel fuel contains some moisture. Moisture accumulates in diesel tanks as condensate droplets on exposed tank surfaces, as dissolved water in the fuel, and as the water layer beneath the fuel microbes depends on this water for growth. In addition, microbes rely on organic and inorganic molecules as fuel for nutrition. Consequently, some species attack the fuel directly, growing at the expense of hydrocarbon and non-hydrocarbon fuel components. Biodegradation of fuel, in support of microbial growth, directly affects pollution. Change color, the heat of combustion, pour point, cloud point, detergent and anticorrosive properties as microbes selectively attack fuel components. Sulfur-containing molecules are metabolized by a series of species, ultimately producing high concentrations of hydrogen sulfide. In addition to making new cells, many microbes produce metabolites that promote further invasion. Surfactants facilitate the elution of the fuel, resulting in the formation of a cloudy, inverted emulsion layer above the fuel/water interface. Polysaccharide slimes create microenvironments where mixed populations of bacteria and fungi carry out biodegradation reactions leading to single degradation. The slime also acts as a barrier, protecting the microbes from the preservatives. Various organic acids (primarily 2-4 carbon atoms) are also produced as by-products of bacterial and fungal growth.

Water in diesel fuel

Water can enter fuel storage tanks from:

●    Rainwater seeping over tank fittings
●    Water in delivered fuel
●    Water from moisture in the air

Water is the most common source of moisture in the air. Fuel tanks are vented. When the fuel is delivered to the tank, the air escapes. When fuel is drained, air enters the tank to fill the void. Any moisture in the air will condense in the relatively cool space inside the tank.

As the temperature rises during the day, the fuel expands, pushing the air out of the tank. The fuel condenses as the temperature drops at night and air enters the tank. This is called diurnal breathing. This can be a significant cause of water entering the tank.

Water is denser than fuel, so inside the tank, it slowly settles to the bottom, forming a layer of water. This layer of water causes significant problems.

The water-fuel interface is an environment where biogrowth can initiate and thrive. This can cause quality test failures, and extreme algae growth and clogging of engine filters can lead to failure.

The water layer can be corrosive that attacks the steel tank bottom. Steel tanks now include warnings about this problem. Water in the fuel can be drawn into the fuel system, where it can cause failure and wear.
Fuel polishing removes water from stored fuel and prevents all these problems.

How is fuel polishing monitored?

The fuel polishing controller monitors the condition of the equipment. The controller can connect to a remote building management system or cloud-based monitoring. Here are the items that are monitored:

a) Dirty filters

Filters are monitored by differential pressure from the inlet to the outlet. When the rated differential pressure is sensed instead of the alarm being activated, it indicates that filter replacement is required.

b) Water in coalescing filters

Water in the coalescer separates from the fuel and settles at the bottom of the filter. As water accumulates, the level rises to the point where the water sensor is triggered, and an alarm is triggered. The water can be drained, and the alarm would reset.

c) Pump flow

A flow sensor proves that the fuel pump is working properly. If not, the controller will show a pump alarm for troubleshooting.

d) Leak detection

The pump and filter assembly must include a containment base in case of fuel leaks and facilitate filter changes. A leak sensor will trigger an alarm on the control panel and stop pump operation until the problem is fixed.

FAQs

1) What are the benefits of using a diesel fuel polisher system?

Regular fuel polishing helps reduce fuel contamination, such as biomass sludge formation. This helps drain any water that gets into the fuel tank.

It also removes solid particles in the fuel. A generator with an inbuilt fuel polishing system automates the fuel cleaning process.

This eliminates the need for any external intervention from generator maintenance service, reducing maintenance costs, effort and time.

2) What is the frequency of the diesel fuel polishing schedule?

In general, fuel polishing should be done at least once a year. Staff in power backup should routinely check how long diesel fuel has been stored. This practice helps in increasing the reliability of generators.

3) What is the purpose of diesel generator fuel polishing?

Diesel generator fuel polishing is the mechanical process of filtering stored fuel through a device or devices that target contaminants that require or reduce the need for expensive and often inefficient fuel additives.

4) Is it necessary to polish the fuel?

This prevents your fuel from going bad and thus helps prevent your generator from breaking down when needed. Fuel polish is achieved by trapping water, microbes, rust and sludge in the filter system.

Conclusion

Diesel generator fuel polishing is an indispensable practice to maintain the efficiency of the generator system. The accumulation of contaminants within diesel fuel can cause several operational problems. Fuel polishing emerges as a proactive solution to combat these challenges, effectively removing impurities and ensuring that the fuel meets stringent quality standards. 

Businesses and individuals can protect their generator investment, extend equipment life, and maintain operational continuity by investing in regular fuel polishing. Adopting this critical conservation practice demonstrates a commitment to excellence and contributes to a greener and more sustainable energy landscape by minimizing wastage and promoting fuel efficiency. As technology evolves, diesel generator fuel polishing remains an essential maintenance pillar, providing peace of mind and confidence in a changing world.