Cold Weather Strategy – FAQ’s
1. How often do you need to take a sample for testing?
A monthly nozzle sample from each storage tank (unless manifolded together) is vitally important to track winter operability, trend the fuel/additive performance and predict potential problems before they occur.
2. Does double treating with additive help the CFPP?
Sometimes a double treat with the additive can help but there is a diminishing return to scale considering the cost of the additive. Requested lab testing of an up-treat will help determine the value of this option. It will be different for different fuels.
3. What does CFPP mean?
This ASTM test otherwise known as “Cold Filter Plugging Point” measures when a fuel will no longer pass effectively through a filter and has started to gel. This is a relative test, which attempts to approximate when a truck filter will experience filter plugging as temperatures drop.
4. Will your trucks run at temperatures above this CFPP number?
The test is decades old but the only one available that is ASTM approved. Ultra Low sulfur diesel, biodiesel, crude-stock blends and filtration all have an impact on the relative accuracy of this test. Time at temperature is also very important in how wax in a fuel precipitates out of solution. Industry knowledge and adjusted CFPP numbers try to establish a more real-world operability number. EMTEC uses an algorithm to correct the CFPP to a more “real-world” temperature at which gelling is likely to occur – EPGP “Emtec’s Projected Gel Point”.
5. When should you initiate use of Red Alert in conjunction with Innospec additive?
When expected cold weather temperatures are approaching 5 degrees of the corrected CFPP number. Also during weekend shut-downs when weather is approaching 0°F
6. What about kerosene blending? When and how much should you use?
Kerosene blending has long been the solution to extending the cold weather operability temperature of diesel fuel. Traditionally it has been quite effective but again all fuels react differently to kerosene. Kerosene is often 20 cents and more than the cost of # 2 diesel and is not readily available. Kerosene lacks the lubricity quality of #2 diesel and has a lower BTU value which increases fuel consumption.
7. Why does my fuel gel and someone else close by has no problems?
In most cases this is because of different operational practices adopted by maintenance. Fuels from different terminals just a few miles apart can exhibit very varied cold flow properties. Wax content of the crude and the crude slate itself can have a large impact on temperatures at which fuel starts to gel. Pipelines can supply a proprietary fuel from a single refinery but mostly diesel fuel across the USA is “fungable” which means several suppliers could be supplying the same terminal in variable percentages.
8. Can you add additional additive if fuel is already reached its cloud point or gelled?
No! Additive needs to be well mixed with the fuel and adding more additive to cold fuel (Cloud point or below) will only result in the additive going to the bottom of the fuel tank and exacerbating the filter plugging problem. Once fuel has reached cloud point or below, the only successful strategy is to warm up the fuel or use Red Alert or another approved anti-gelling and de-icing product.
9. Why does your fuel gel after you have left service center and your truck was running fine for first 5 – 15 minutes?
During cold temperatures it is not unusual for a truck to start and run normally until it has driven several miles before the filters start to plug. This is because the wax may be settling out of the fuel but not enough to plug the filters with the small volumes passing through the filter during idle. As the driver begins to accelerate (especially under load), the higher volumes of fuel passing the filter start to plate off on the filter media and filter plugging can rapidly occur.
10. Should you idle your truck before leaving service center in extreme cold temperatures?
Yes! Although many best practices adopted by fleet trucking companies restrict engine idling, it should be allowed during extreme cold weather. Most newer engines (especially engines with high pressure common rail fuel injection systems) return significant amounts of fuel to the tank. This return fuel (spill) is warmed by the pump pressures and mechanical effects of the system and will warm the fuel in the tank and therefore the fuel going back through the filters. Straight idle returns a much smaller volume of fuel than a high idle – so if possible maintain a high idle and the fuel in the tank will warm faster.
All fuels are definitely not equal and they all respond differently to additive and/or kerosene blending. Despite this fact it is still necessary to establish some standard guidelines in preventing fuel from gelling and how and when to use anti-gelling and de-icing products such as the recommended RED ALERT additive provided by Innospec.
If temperatures are expected to drop between 0°F and -10°F.
- Add RED ALERT directly to the saddle tank at a treatment level of one 32oz. bottle per 50 gallons of diesel fuel.
- Overall RED ALERT treatment ratio should not exceed one 32oz. Bottle of RED ALERT per 50 gallons of diesel fuel.
- Idle or run engine for 10 to 15 minutes to ensure all fuel and the filter are treated
Then it is imperative that operator let engine idle for an additional 30-45 minutes before leaving the yard. This will allow warm fuel to return to fuel tanks and vital engine components. Thus dissolving any wax or ice left in fuel. If adequate warm up time is not allowed, heavy waxy fuel will load up fuel system and engine will shut down due to fuel starvation.If
If temperatures are expected to go below -10°F to -20°F
- Red Alert treatment procedures as above.
- Double treat the additive – lab reports with double treating can be used to judge effectiveness.
- Trucks with engine block heaters should be plugged in overnight.
- If time and product is available, kerosene should be added to the storage tank. Sometimes even 20% kerosene can make a big difference. Lab results can validate the performance.
If temperatures are expected to go below -20°F.
- Same strategy as above but kerosene becomes very important.
- Use a 50/50 blend if possible or whatever the storage tank will hold.
- Remediation procedures for gelled fuel.
Morning of operation before equipment is started if fuel appears to be gelled:
(Do NOT add additional Cold Flow Improver (CFI additives) to cloudy or gelled fuel)
Using RED ALERT:
- Spin fuel filter and saturate said filter with contents of one 32 oz. bottle of RED ALERT.
- Pour remaining contents of the bottle and one additional bottle into the saddle tank.
- Overall RED ALERT treatment ratio should not exceed one 32oz. Bottle of RED ALERT per 50 gallons of diesel fuel.
- Wait 30 to 60 minutes before attempting to start the engine.
- Then it is imperative that operator let engine idle for an additional 30-45 minutes before leaving the yard. This will allow warm fuel to return to fuel tanks and vital engine components. Thus dissolving any wax or ice left in fuel. If adequate warm up time is not allowed, heavy waxy fuel will load up fuel system and engine will shut down due to fuel starvation.
Note: Proactive RED ALERT treatment is especially important if cold temperatures are expected during weekend shutdowns.
Additional comments
- Use Innospec winter additive consistently and at the correct treat rates.
- Always top up fuel tanks prior to equipment shut down.
- Always test equipment fuel for entrained water content. Constantly monitor fuel/water separators.
- Constantly monitor fuel system for microbial contamination.
- For best winter operability use highest OEM accepted micron fuel filters. Example 10-15 micron fuel filters as opposed to 2-5 micron fuel filters.
- Pro act instead of react. Prepare your equipment prior to anticipated cold weather system.
EMTEC’s Recommendation to Prevent Gelling
The following recommendations were developed in cooperation with Detroit Diesel Corporation after an extensive study on the cooling effects of the saddle tanks while driving at different speeds and understanding the fuel flow dynamics of modern Detroit Diesel engines.
First recommendation:
- Drivers’ should fuel up at the BEGINNING of each shift especially during weekend shut-downs.
- Filling up at the BEGINNING of each shift from an underground storage tank will introduce warmer fuel (approximately 54°F) into the saddle tanks.
- Above ground tanks may be less than 54°F depending on their size, but the fuel will still be much warmer than the fuel left overnight or over the weekend in a saddle tank.
- During extreme cold, RED ALERT must still be added into the saddle tanks as recommended in the RED ALERT Product guidelines. Driver adds Red Alert after his last stop in proportion to the remaining fuel in the tank. This will allow the RED ALERT to be distributed through the fuel system and eliminate the need for idling the truck if he only adds the RED ALERT at the end of shift. When the driver fuels up the following day or Monday morning, the remaining RED ALERT (from 32oz bottle) is added to treat the added fuel volume.
- Any issues surrounding condensation and icing from unfilled tanks left overnight or over the weekend should be addressed by using Innospec’s RED ALERT as recommended.
Second recommendation:
- Idle the engine longer than 3 minutes. Idling longer will allow under-hood temps to warm up, and prevent the convection (i.e. heat loss) from the ram-air passing over the tanks while driving.
- Although most fleet trucking companies have 3 minute idle shut-down policies, it would be very pruedent to allow drivers to idle longer during extreme temperatures. Gelling problems are very likely to occur after the vehicle has left the client site location and ram air cools the fuel before it has had a chance to warm up from return fuel. In order to do this efficiently, reprogramming to allow longer idle times or winter disengagement of the 3 minute idle shutdown would have to be considered. DO NOT DISENGAGE THE PARKING BRAKE TO ACCOMPLISH LONGER IDLE TIMES!
DDC did a study on the heat loss through fuel tanks: Assuming a 160 gallon tank capacity that is at 22 inches fill level….
- The fuel tanks will provide approximately ~410 W of cooling at 0 mph
- The fuel tanks will provide approximately ~775 W of cooling at 5 mph
- The fuel tanks will provide approximately ~1090 W of cooling at 10 mph
- The fuel tanks will provide approximately ~1490 W of cooling at 20 mph
- The fuel tanks will provide approximately ~1900 W of cooling at 40 mph
- The fuel tanks will provide approximately ~2350 W of cooling at 80 mph
To give some idea of the cooling equivalent of watts of cooling:
One Ton with respect to Refrigeration equals 12000 BTU/hr. (British Thermal Units)so 12000 BTU = 3.516 Kilowatts =3516 Watts. A one ton air conditioning cooler is equivalent to the air conditioning required for a medium sized house.
In summary….those fuel tanks are going to severely slow down the warm-up process as soon as they see wind across them. The cooling effects of driving can off-set any of the benefits of warm return fuel heating the fuel system.
As far as engine flow is concerned, the volumetric flow from the tanks doesn’t really increase that much over engine speed. However the volumetric flow through the engine filter does increase dramatically. Idle at 700 rpm or more to get more recirculation, and let under-hood temps warm up as much and as quickly as possible.
The following chart shows return fuel rates (in litres per hour) at different engine speeds
| Engine Speed | |||||
| 600 rpm | 700 rpm | 1000 rpm | 1300 rpm | ||
| Volume – module in | l/hr. | 440 | 460 | 490 | 510 |
| Volume – gear pump out | l/hr. | 450 | 530 | 775 | 950 |
| Recirculated Volume | l/hr. | 10 | 70 | 285 | 440 |
| % Recirculated Flow | % | 2% | 13% | 37% | 46% |