About Biodiesel

In response to the recent passage of Minnesota’s bill requiring 2% biodiesel in all diesel fuels starting as early as July 1, 2005, the National Biodiesel Board convened a Cold Flow Consortium. The Consortium was tasked with investigating the blending of biodiesel into diesel fuel at temperatures similar to those experienced in the Minnesota winter, with the objective of defining parameters for successfully preparing homogeneous single-phase blends. The Consortium was composed of fuel providers, marketers, blenders, and other interested parties. Each member had an equal voice in the Consortium.

Scope Biodiesel
This study was designed to accurately determine the temperature where biodiesel and No. 1 and No. 2 diesel could be blended at 2 volume percent (2%) biodiesel, while meeting standards for blend precision and homogeneity. The approach taken was to fabricate a small scale blending system to simulate splash and proportional blending. The system has the capability to blend biodiesel at different rates with different grades of diesel fuel at different temperatures. This study focused on preparing 2% biodiesel (B2) blends exclusively. The blending system was self-contained to include tanks, pumps, motors, and necessary appurtenances. The system included the ability to heat and/or cool the biodiesel as needed and cool the diesel as needed.

Experimental Apparatus
The test unit was designed to be totally portable to allow for future testing at various locations. The design of the test skid was specifically sized for testing B2 as mandated in the state of Minnesota. The test skid included an environmental chilling chamber, capable of cooling fuel to near -60ºF in a reasonably short period of time. A photograph of the blending unit is in Figure 1. Each process and test was recorded manually and with video equipment along with the blending equipment records of volume amounts. To assist in recording the results of these tests, the finished product tank included interior lighting, viewing ports, and sample ports. The finished product tank was manufactured of a clear material to offer the best possible opportunity for evaluating the formation of crystals. The design for the first series of testing simulated splash blending into a clear blending container maintained at ambient temperature. A process and instrumentation diagram (P&ID) of this test bench configuration is contained in Appendix A. For proportional blending, a flow loop was created to allow the fuels to circulate through the piping while inside the cooling chamber. The piping loop included a filter and differential pressure across
the filter was employed to monitor fuel viscosity changes and determine if the fuels were plugging the filters or strainers. Large increases in viscosity or filter plugging would indicate the formation of wax or biodiesel crystals.

Test Procedures
Sequential Blending into Visible Container. These tests simulated splash blending. Four scenarios were tested:

1. Cold No. 1 diesel was loaded into the container. The first type of biodiesel was added to the top to create a B2 blend. This procedure was repeated for each type of biodiesel.
2. Cold No. 2 diesel was loaded into the container. The first type of biodiesel was added to the top to create a B2 blend. This procedure was repeated for each type of biodiesel.
3. Biodiesel was loaded into the container first. The No. 1 diesel fuel was loaded on top to create the B2 blend. This scenario was repeated for each type of biodiesel.
4. Biodiesel was loaded into the container first. The No. 2 diesel fuel was loaded on top to create the B2 blend. This scenario was repeated for each type of biodiesel.

Proportional Blending. The biodiesel and diesel fuels were blended through proportional blending. To accomplish this, four gallons of cold No. 1 or No. 2 diesel fuel were circulated through the filters and the pressure drop across the filters measured. Biodiesel was then proportionally blended at 2% and any change in the filter pressure drop monitored. This procedure was repeated with each of the three biodiesels.

Test Fuels
A local truck rack operator provided the diesel fuels for this project. The fuels were unadditized commercial grades of No. 1 and No. 2 diesel fuels. The certificates of analysis are in Appendix D and E, respectively. The biodiesels were soy-, yellow grease-, and tallow-derived fuels. The certificates of analysis are in Appendices F, G, and H, respectively. West Central Soy provided the soy biodiesel. Rothsay/Laurenco provided the yellow grease and tallow biodiesels. The biodiesels were sent to a test facility to measure the cloud and pour points of the neat biodiesels and the B2 blends. Because the unadditized diesel fuel (Appendices D and E) was not available, a typical no. 2 diesel was used to make the blends for cloud point and pour point determination.

source : http://www.biodiesel.org

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Ditulis oleh William Perkasa pada tanggal Monday, August 11, 2008