Production of BHD (Bio Hydrofined Diesel) with Improved Cold Flow ...

Decarbonation Selectivity,%
50
40
30
20
10
0
3MPa
6MPa
100 200 300 400
Reaction Temperature,℃
Fig. 3
Reaction temperature and decarbonation selectivity
From Fig. 2, it can be seen that the decarbonation reaction requires less hydrogen than the
dehydration reaction, for the same amount of deoxygenation. Also, decarbonation is less of an
exothermal reaction than dehydration. Therefore, reaction conditions of high decarbonation selectivity
are better from the standpoint of the suppression of hydrogen consumption and exothermicity.
However, when decarbonation selectivity increases, the carbon number of the produced hydrocarbon
decreases and gas oil yields decrease, and carbon dioxide emissions increase; these are disadvantages.
When designing a process of BHD production, we should consider all of these aspects.
2.3 Test run using BHD
We conducted a field test using an actual vehicle, whose fuel contained BHD produced by the
method stated above. The test was conducted from October 2007 to March 2008 in collaboration with
the Tokyo government, Toyota and Hino. The field test was completed with no problems. The details
of the test are described in the paper; "Verification Test of Bio Hydrofined Diesel by Tokyo City
Hybrid Bus" JSAE 20085928.
2.4 Comparison between BHD and FAME
The accelerated oxidation test results for BHD and FAME are shown in Table 4. Oxygen was
bubbled through the oil for 16 hours at 115°C. Acid numbers were measured before and after the test.
Compared to FAME, BHD showed a much smaller acid number increase in the accelerated
oxidization test, confirming its superior oxidation stability. This is because the oil’s unsaturated bonds
have been hydrogenated, and we can say that this allays concerns currently held about problems with
FAME use.
Table 4
Oxidation Stability of BHD and FAME