Since 1948
and No . 2 grades using the same test methods and limits while adding oxidation stability reserve and acid value and allowing a slightly T-90 .
Currently , biodiesel / heating oil blends at levels up to B5 are commonly used in heating systems in the Northeast . This is a fully accepted fuel in existing equipment and fueling infrastructure and is being embraced by much of the market as a means to reduce the carbon footprint of home heating oil while providing other environmental , economic , and performance benefits .
With the research and testing completed on B20 that has resulted in the B6-B20 grade in the ASTM D396 standard , 1-3 several retail fuel oil marketers have been successfully selling B20 blends to their existing heating oil customer base for over 10 years , while some early adopters are using blends over B20 . As biodiesel production increases through plant capacity growth , improved crop yields , increased waste resource use , and novel crops including algae , there is a potential to also increasingly displace petroleum with this renewable fuel . The work done in this research explored specific aspects of the use of biodiesel at blend levels of 20 % and over .
The specific technical aspects evaluated over several projects included : 1 . Compatibility of conventional fuel pump shaft seals with higher blend levels . 2 . Evaluation of pumps under field operating conditions 3 . Impact of exposure of “ yellow metals ” at low and high temperature on biodiesel blends . 4 . Combustion characteristics of biodiesel blends and flame sensor response . 5 . Documentation of field experience with biodiesel blends including higher blend levels .
Work done and results of studies for each of these aspects are described in the following sections . As part of the work on this project , BNL spearheaded a series of review documents for submission to ASTM for their consideration in updates to the D396 standard on heating oil . These reviews were important for this process and include important background information on combustion performance and other areas . [ Editor ’ s note : A package of review documents included as Appendix I to the original report is not included with this excerpt .]
PUMP SEAL MATERIAL EVALUATION
Oil burners commonly used in homes and smaller commercial applications are fixed firing rate , with pressure atomized burner nozzles . Fuel pressure delivered to the nozzle is typically 100 – 150 psi . The fuel pump in these systems are gear-type positive displacement pumps which include the following features :
• An integral pressure regulator with adjustable discharge pressure .
• Some type of flow control which only allows flow to the nozzle when the pump is running and quickly turns the flow on and off during cycling operation .
• An inlet strainer .
• High suction lift to rapidly clear air out of an empty suction line .
In oil burner pumps there are several different seals used . In consultation with the pump manufacturers and other industry stakeholders , the pump shaft seals were identified at the start of this project at the area of most concern . A leaking shaft seal has potential to allow oil to drip onto the floor of the home , an undesirable outcome . The most common pump types used in North America include lip-type shaft seals with a specific nitrile material . Less common , but still important are carbon-face type shaft seals . In this section of this report , work done on the basis interaction between the nitrile used in most pump shaft seals and biodiesel blends is presented . The evaluation of pumps under operating conditions with lip seals and carbon-face seals is discussed in the next section . The work that is the subject of this section has been focused on the impact that biodiesel blend use can have on the nitrile seal material used in the market-dominant fuel pump shaft seal . This is a nitrile lip seal and , while the focus is on this specific seal , nitrile generally is used in other legacy heating system seal applications including other pump , filter , and valve components . The focus on this specific seal was a decision made in consultation with pump manufacturers . A leak in the shaft seal could potentially lead to fuel spillage inside of the building space .
Figure 1 provides a photo and sketch of the lip seal used in the burner pump installed in a strong majority of building heating applications in the U . S . It is a common double-
Since 1948
Petroleum Storage
Plant Equipment
732-764-7270
New England 207-358-9685
Florida 305-767-0807
Bio Blending Systems Additive Injection Systems
www . fueloilnews . com | FUEL OIL NEWS | FEBRUARY 2019 27