New Cold Weather Problems with Biodiesel Identified

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New Cold Weather Problems with Biodiesel Identified
The recent bout of very cold weather in the northern tier states has shown new issues with biodiesel blends containing as little as 2% biodiesel.

We are seeing a significant number of customers that are having problems with the filters on their diesel fuel dispensers.
In nearly every case the customers are receiving a B2 to B5 blend.

In most of these cases they are not having vehicle or equipment problems, but rather problems getting the fuel from the storage tank to the vehicle tank. The dispenser filters seem to plug anywhere from a few hours to a few days of operation.

These filters when opened contain what at first appears to be wax. However when analyzed this material appears to be a glycerin type material. If you then bottom sample the storage tank, you generally find a material that resembles cottage cheese. There is often a layer that starts at the tank bottom and can be several inches thick of this material.

When this layer reaches the level of the pickup tube it can very quickly plug the dispenser filter.

This issue has several variations and we have identified several potential causal factors.

  1. Fuel that has a high level of dissolved water. This high water content seems to be a significant factor in all of these cases.

  2. Fuel derived from animal fats (including plant / animal blends of biodiesel) seems to be a factor in these problems.

  3. Long periods (more than 72 hours) of temperatures below 32 F (the longer it is cold and the colder the average temperature the greater the problem).
    Above ground versus in-ground fuel storage.

  4. Use of additives Some help, some make things worse.
    CP, CFPP, PP of the diesel portion of the blended fuel.

  5. Quality of the blend procedure and temperature at which the fuel and biodiesel are blended.

  6. Storage period.

Another factor in the rapid plugging of these dispenser filters is that as filter media starts to plug the filter actually begins to reduce the micron size of the media so that the filter picks more and more material that is smaller and smaller.

Also consider that a diesel engine tends to heat the fuel during the recirculation process whereas a dispenser provides no heat.

We offer some suggestions for users experiencing these problems.

  1. If you have this problem today you can go to a dispenser filter with a large micron size. There are winter filters available from Cim-Tek with a cleanable 144 micron stainless steel mesh.

  2. You can have the tank pumped from the bottom to remove this material. Depending upon your tank size, you may need to remove 50 to as much as 300 gallons to eliminate this problem.

  3. You can add certain types of additives that will break this material down and return it to solution.

  4. You can add kerosene (Note: if you have Ultra-Low Sulfur Diesel, you MUST use Ultra-Low Sulfur Kerosene). ULSD Kerosene is very expensive and it can take a lot of it to resolve this problem.
    Ask for your next two or three loads of diesel to be delivered with no biodiesel.

  5. Ask for biodiesel blends derived only from plant base oils during the fall and winter months.

  6. Additization with the correct products can help to prevent these problems.
    If you have access to biodiesel that has been through a distillation process, you will have far less problems.

Diesel Doctor

Copyright 2009


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Last modified: 04/06/09
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