Showing posts with label Water. Show all posts
Showing posts with label Water. Show all posts

Wednesday, February 18, 2009

Fuel Storage Tank Maintenance - Keep It Clean

Keep It Clean - Fuel Storage Tank Maintenance


Most owners and operators of fuel storage tanks do not understand that maintenance is required to safely and successfully operate fuel storage tanks.

We constantly hear that customers have tanks that have never been cleaned and worse yet, that they believe that they never need to check to see if they have any problems.

This is made even worse by the information that some fuel suppliers tell their customers; for example that it OK to have some water at the bottom of the tank.

Well here is some real world information for everyone on this subject.

Fuel Storage Tanks all require regular maintenance. They are designed with the pickup tube 3" to 6" from the tank bottom so that small amounts of water, sediment and other contaminants have a space they can settle out so that they will not be drawn into the vehicle or equipment tanks as fuel is pumped out. This water and sediment material will accumulate over time and will cause problems if not removed periodically.

Some will tell you that 1/2" or 1" or even 2" of water is alright, and they are flat out wrong. Every time fuel is transferred into that tank it stirs up all that material and it may take as long as a day for it to settle out again. In the meantime every tank you dispense fuel into gets some of this material.

If you have a steel tank that water is corroding your tank from the inside out and putting rust particles into your fuel. We often find above ground tanks only a few years old that have rusted from the inside to the point of leaking from water and sludge in the tank.

Many customers have electronic monitoring systems that provide constant readings showing fuel level, water level, and leak detection. Some of these customers will see 1/2" or a few gallons of water on these system and ignore it because they have been told it is not important.

One problem we see time and again is that the sensors on these monitoring systems fail and they don't tell you when they fail, they just go on showing the last reading forever. This goes on until they start pumping water into their equipment at which point someone checks the tank with a stick and water finding paste only find that they actually have several inches of water.

We have told all of our customers for many years that even though you have spent several thousand dollars for a state of the art monitoring system, you still need to have some one check every tank at least once a month with a stick and water finding paste.

And this rule should be written next to the monitor and maybe next to where you store the measuring stick: "The Only Acceptable Amount of Water in Any Fuel Storage Tank is ZERO (0)".

For those of your with in-ground steel tanks, these tanks have Sacrificial Anodes attached to them. These Anodes take the weak electrical current generated by the tank and pass it into the ground through them. This prevents the tank metal from corroding, however the Anode "Sacrifices" itself in this process. The Anode is used up over a period of time. When the Anode is "used up" the tank begins to corrode often very quickly. Tank owners should periodically check these Anodes and Replace them as necessary. In many states this is part of the required maintenance and testing procedures, however you should know this and check to be certain it has been properly done.

Caps, Sumps, and Vents should all be checked for integrity and to see that they are doing their intended job.

Fuel Storage is a vital link in getting clean fresh fuel safely and efficiently into vehicles and equipment. You have a big investment in the tank, its installation, and in the fuel in it. It only makes sense to properly maintain and protect this investment.

Today we have new challenges with Ultra-Low Sulfur Diesel (ULSD), Biodiesel, Gasohol, Conventional Gasoline, and Reformulated Gasoline containing any amount of Ethanol. These fuel products hold much higher levels of water and are much more corrosive than fuels we have traditionally dealt with. They require much higher levels of monitoring and maintenance to have a safe and trouble free delivery system.

We are happy to offer analysis and suggestions on how to operate and maintain your systems.

Please post your comments or questions here.

Diesel Doctor

Friday, February 6, 2009

New Cold Weather Problems with Biodiesel Identified

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.


Please let us know about your experiences with these problems