Processing of Primary Fischer-Tropsch Products - University of Alberta

More documents

Recommendations

Info

$MATH 209, Lab 5$

0.90 ........ i ....... i ...... ~ ...... i ....... i- ....... i ....... T ...... ~ ....... T ....... 250 ............. ""i. " .................................................................................... i ! i ! i i i i 0.87 . , . . . 200 0.81 iiiiiiiiiiiill i i "''i'~. [Sulphurl i i iiiiiiiiiiii ..... ......... i ......... 0.78 .......... ! ......... i ......... i ......... I.'..D. ::ii.i~! .... i . ~ so ! ! ! ! ",= . , I I I ", 9 . , 0.75 ; : 0% lO% 20% 30% 40% 50% 60% 70% 80% 90% 100% Sasol SPD Diesel in Blend, % vol Figure 10 Sasol SPD TM diesel US 2-D-diesel blends: density and sulphur content Table 10 Average results from the emission tests with CARB, Sasol SPD TM and US 2-D diesel fuels Sasol SPD TM Diesel - US 2-D blend, % vol CARB 0% 30% 50% 80% 100% Diesel Transient Emissions 9 Hydrocarbons HC g/kWh 0.22 0.13 0.11 0.09 0.09 0.13 9 Carbon Monoxide CO g/kWh 3.83 3.17 2.9 2.62 2.57 3.34 9 NOx NOx g/kWh 7.05 6.17 5.72 5.3 5.08 5.96 9 Particulate PM g/kWh 0.277 0.278 0.265 0.241 0.218 0.276 9 BSFC (a) g/kWh 236 237 231 228 231 233 Test Engine 12,7 L DDC series 60 (1988), rebuilt to 1991 emission levels Rated Power 261 kW @ 1 800 rpm Peak Torque 1 830 Nm @ 1 200 rpm (a) Brake Specific Fuel Consumption (BSFC) If a blend is aimed at meeting the CARB specification then the boiling point range of the LTFT diesel will need to be adjusted accordingly. LTFT diesel can be blended with any current diesel fuel on the market to produce a blend that conforms to the CARB specification. In the case of a blend with US 2-D diesel, 30% LTFT diesel in the blend is more than sufficient to meet the CARB specification in all respects except the aromatics content and the emissions performance is nearly equivalent. 80% LTFT diesel will be required to meet the CARB specification for aromatics but then a higher density third blend 150 100 g~ o k 519
520 component e.g. biodiesel and/or some other heavy oxygenated hydrocarbons will be required to meet the density specification. If biodiesel is used then it is also free of aromatics so that the combined amounts of LTFT diesel and biodiesel in the blend will be about 80%. This blend will have an emission performance that is far superior to conventional CARB diesel. 7.1.3 LTFT diesel environmental characteristics Sasol also evaluated the biodegradability and ecotoxicity characteristics of the Sasol SPD TM diesel, including some petroleum fuels for comparison. The biodegradability was measured using the modified Stunn OECD 301B method, based on the carbon dioxide evolution. It was found that the synthetic diesel can degrade rapidly and completely in an aquatic environment under aerobic conditions. Petroleum fuels tested simultaneously behaved differently, with lower degradation rates under the same conditions. The bacterial toxicity was determined using the OECD method 209 based on activated sludge respiration inhibition. From a toxicity perspective, the Sasol SPD TM diesel performed similarly to petroleum based fuels. 7.1.4 LTFT diesel product applications The best use of the synthetic LTFT diesels will be to upgrade, by blending, the quality of conventional diesel fuels. Based on their superior quality, the synthetic distillates are the ideal, high value, blending component for upgrading of lower-quality stock derived from catalytic and thermal cracking operations, for example cycle oils [81, 82]. In 1948 JA Tilton from the Esso Standard Oil Company suggested that "there is a possibility that the Fischer-Tropsch synthesis process may eventually be a source of premium quality Diesel fuels" [83]. It is interesting to note that it was also anticipated that blends of the use of these high Cetane number diesels with lesser fuels were usable to meet a 50 Cetane specification, concluding that these high Cetane number fuels "might be used either alone or as blending agents". The blend material from conventional processing includes product from FCC and Coker units. The blended final product will be low in sulphur and aromatics, a fuel compatible with demanding environmental legislation. Hence the products could enter a market where the LTFT diesel characteristics are valued as blend material to meet local requirements. It is also possible to use this fuel as a neat fuel in applications where its premium characteristics are desired. 7.2 LTFT naphtha The characteristics and applications of the Sasol SPD TM naphthas have been the subject of presentations at recent international meetings [77, 84]. Four LTFT naphthas can be produced using the process configurations summarised in Table
Page 1 and 2: Studies in Surface Science and Cata
Page 3 and 4: 484 Cold separation .~~"~ Condensat
Page 5 and 6: 486 Chemical production at the Moss
Page 7 and 8: 488 Table 1 Research octane value (
Page 9 and 10: 490 cannot be used with FT products
Page 11 and 12: 492 an attractive refining option f
Page 13 and 14: 494 pose a serious refining problem
Page 15 and 16: 496 offset by the higher capital co
Page 17 and 18: 498 technology that can be used to
Page 19 and 20: 500 includes conventional petroleum
Page 21 and 22: 502 environmental footprint refers
Page 23 and 24: 504 option depending on the scale o
Page 25 and 26: 506 yielding a much higher selectiv
Page 27 and 28: 508 conditions are significantly le
Page 29 and 30: 510 protonated on the acidic cartie
Page 31 and 32: ~ .I Condensat, i ,~ ~l Cond,nsate
Page 33 and 34: 514 product upgrading unit is compa
Page 35 and 36: 516 broad terms, the information re
Page 37: 518 7.1.1 LTFT diesel as a blending
Page 41 and 42: 522 A comparison of the characteris
Page 43 and 44: 524 100 -[ ........................
Page 45 and 46: 526 60.0 . . : . . . i i ! i i i .
Page 47 and 48: 528 of hydrocarbon products, the pr
Page 49 and 50: 530 [41 ] F.D. Rossini, Chemical th
Page 51: 532 [83] J.A. Tilton, W.M. Smith an

Processing of Primary Fischer-Tropsch Products - University of Alberta

Create successful ePaper yourself

Delete template?

Save as template?