Hydrocracking and Hydroisomerization of High-Density Polyethylene and Waste Plastic over Zeolite and Silica−Alumina-Supported Ni and Ni−Mo Sulfides

Abstract

Conversion of plastic waste into transportation fuels over bifunctional catalysts was systematically studied. Previous work showed that some acid catalysts were active for degradation of pure polyolefins, but they were easily deactivated by nitrogen, sulfur, and impurities contained in actual postconsumer plastic waste. Ni and NiMo sulfides loaded on a hybrid support (HSiAl), a mixture of HZSM-5 and silica−alumina, were found to be effective for converting both pure high-density polyethylene and plastic waste to gasoline-range products. Hydrocracking reactions were carried out mostly at 375 °C, 1000 psig H2 (initial), for a reaction time of 1 h, though the effects of initial hydrogen pressure and reaction time were also examined. Ni/HSiAl had higher hydrocracking and hydroisomerization ability than did NiMo/HSiAl. The quality of liquid products obtained over Ni/HSiAl was comparable to that of a commercial premium gasoline. Moreover, being resistant to poisoning by N- and S-containing compounds, these catalysts could be regenerated simply by recalcination and resulfiding.

Cooperative Research Program in Coal-Waste Liquefaction

“…These include HZSM-5 and other zeolites, silica-alumina, titania-silica, titanium chloride, sulfated and tungstated zirconia, nanoscale iron oxides promoted by sulfate or secondary metals, various supported transition metal catalysts and a number of metal-promoted solid acid catalysts. (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37) Two types of commingled postconsumer plastic have been investigated: a relatively clean plastic provided by the APC that had been subjected to a washing process; and a processed but considerably dirtier post-consumer plastic provided by the DSD. The latter sample was supplied to the CFFS in the same granular form used by the KAB liquefaction plant and other feedstock recycling plants in Germany.…”

“…Direct liquefaction experiments have been conducted the APC plastic as a function of temperature, hydrogen or nitrogen pressure, and solvent (no solvent, waste oil, tetralin, and waste oil-tetralin mixtures). (23)(24)(25)(26)(27)(28)(29)(30) Liquefaction yields at 430-450 °C under low hydrogen pressures (100-200 psig, cold) or under nitrogen were not markedly different than those under high hydrogen pressures (800 psig, cold). The best results were obtained with no solvent or with an aliphatic solvent such as waste oil.…”

“…Shabtai and coworkers, however, have developed solvent pre-treatment methods to remove O-and N-containing polymers that render commingled plastics susceptible to low severity liquefaction using these catalysts. (36) Ding et al (27) have been successful in carrying out catalytic liquefaction of the APC commingled plastic at 375 °C. Using 20 or 40% additions of sulfided Ni or NiMo supported on silica-alumina or silica-alumina/HZSM-5, they achieved oil yields of 40-65%, as compared with a thermal liquid yield of only 8% at that temperature.…”

“…or a metal-promoted solid acid catalyst in this reactor will increase the yield of gasoline range, higher octane, product, as discussed earlier. (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) Chlorine levels of the product leaving this reactor should be reduced to 10-20 ppm or less. (41) Upgrading module: The upgrading module is fairly standard with one or two exceptions.…”

Municipal Waste Plastic conversion into Different Category Liquid Hydrocarbon Fuel

“…By using NSR's new technology we can convert all types of waste plastics into liquid hydrocarbon fuel by setting temperature profile 370 degree C to 420 degree C, we can resolve all waste plastic problems including land, ocean, river and green house effects. Many of researcher and experts have done a lot of research and work on waste plastics; some of the thesis's are on thermal degradation process [1][2][3][4][5][6][7][8][9][10], pyrolysis process [11][12][13][14][15][16][17][18][19][20] and catalytic conversion process [21][22][23][24][25][26][27][28][29][30]. Producing fuels can be alternative of heating oil, gasoline, naphtha, aviation, diesel and fuel oil.…”