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Energy-Efficient Routes for the Production of Gasolinefrom Biogas and Pyrolysis Oil — Process Design and Life-CycleAssessment

View Article: PubMed Central - PubMed

ABSTRACT

Twonovel routes for the production of gasoline from pyrolysisoil (from timber pine) and biogas (from ley grass) are simulated,followed by a cradle-to-gate life-cycle assessment of the two productionroutes. The main aim of this work is to conduct a holistic evaluationof the proposed routes and benchmark them against the conventionalroute of producing gasoline from natural gas. A previously commercializedmethod of synthesizing gasoline involves conversion of natural gasto syngas, which is further converted to methanol, and then as a laststep, the methanol is converted to gasoline. In the new proposed routes,the syngas production step is different; syngas is produced from amixture of pyrolysis oil and biogas in the following two ways: (i)autothermal reforming of pyrolysis oil and biogas, in which thereare two reactions in one reactor (ATR) and (ii) steam reforming ofpyrolysis oil and catalytic partial oxidation of biogas, in whichthere are separated but thermally coupled reactions and reactors (CR).The other two steps to produce methanol from syngas, and gasolinefrom methanol, remain the same. The purpose of this simulation isto have an ex-ante comparison of the performance of the new routesagainst a reference, in terms of energy and sustainability. Thus,at this stage of simulations, nonrigorous, equilibrium-based modelshave been used for reactors, which will give the best case conversionsfor each step. For the conventional production route, conversion andyield data available in the literature have been used, wherever available.Theresults of the process design showed that the second method (separate,but thermally coupled reforming) has a carbon efficiency of 0.53,compared to the conventional route (0.48), as well as the first route(0.40). The life-cycle assessment results revealed that the newlyproposed processes have a clear advantage over the conventional processin some categories, particularly the global warming potential andprimary energy demand; but there are also some in which the conventionalroute fares better, such as the human toxicity potential and the categoriesrelated to land-use change such as biotic production potential andthe groundwater resistance indicator. The results confirmed that eventhough using biomass such as timber pine as raw material does resultin reduced greenhouse gas emissions, the activities associated withbiomass, such as cultivation and harvesting, contribute to the environmentalfootprint, particularly the land use change categories. This givesan impetus to investigate the potential of agricultural, forest, oreven food waste, which would be likely to have a substantially lowerimpact on the environment. Moreover, it could be seen that the sourceof electricity used in the process has a major impact on the environmentalperformance.

No MeSH data available.


A comparison of acidificationpotential (AP) for the three cases.
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fig8: A comparison of acidificationpotential (AP) for the three cases.

Mentions: On the other hand, theacidification potential, which can be seenin Figure 8, showsthat the performance of all three cases is almost the same. The mainsubunit contributing the most to all cases is the unit “Electricityfor the compressors”, which is comparable in all three. Theelectricity in all three case comes from the grid, which is a mixof all sources of electricity production. This mix is dominated bynuclear energy, followed by natural gas, coal, and waste. Power plantscontribute significantly to SO2 and NOx emissions,68 which lead to sucha high influence from them in the AP category. For the Base case,the natural gas is the biggest contributor; this shows that the extractionof natural gas consumes resource that give out considerable emissionswhich impact the acidification potential. For ATR, the cultivationand harvesting of timber pine makes a large impact. This can be attributedto the diesel fuel needed to transport the timber to the saw mill,and the power input required from the grid to run the saw mill. Thesesteps draw on resources which impact the overall emissions of theprocess. Similarly, for CR, the energy for harvesting the ley grasscomes from diesel, which runs the vehicles. This diesel comes fromcrude oil distillation, which is a highly energy-intensive processin itself, and results in significant emissions.


Energy-Efficient Routes for the Production of Gasolinefrom Biogas and Pyrolysis Oil — Process Design and Life-CycleAssessment
A comparison of acidificationpotential (AP) for the three cases.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384482&req=5

fig8: A comparison of acidificationpotential (AP) for the three cases.
Mentions: On the other hand, theacidification potential, which can be seenin Figure 8, showsthat the performance of all three cases is almost the same. The mainsubunit contributing the most to all cases is the unit “Electricityfor the compressors”, which is comparable in all three. Theelectricity in all three case comes from the grid, which is a mixof all sources of electricity production. This mix is dominated bynuclear energy, followed by natural gas, coal, and waste. Power plantscontribute significantly to SO2 and NOx emissions,68 which lead to sucha high influence from them in the AP category. For the Base case,the natural gas is the biggest contributor; this shows that the extractionof natural gas consumes resource that give out considerable emissionswhich impact the acidification potential. For ATR, the cultivationand harvesting of timber pine makes a large impact. This can be attributedto the diesel fuel needed to transport the timber to the saw mill,and the power input required from the grid to run the saw mill. Thesesteps draw on resources which impact the overall emissions of theprocess. Similarly, for CR, the energy for harvesting the ley grasscomes from diesel, which runs the vehicles. This diesel comes fromcrude oil distillation, which is a highly energy-intensive processin itself, and results in significant emissions.

View Article: PubMed Central - PubMed

ABSTRACT

Twonovel routes for the production of gasoline from pyrolysisoil (from timber pine) and biogas (from ley grass) are simulated,followed by a cradle-to-gate life-cycle assessment of the two productionroutes. The main aim of this work is to conduct a holistic evaluationof the proposed routes and benchmark them against the conventionalroute of producing gasoline from natural gas. A previously commercializedmethod of synthesizing gasoline involves conversion of natural gasto syngas, which is further converted to methanol, and then as a laststep, the methanol is converted to gasoline. In the new proposed routes,the syngas production step is different; syngas is produced from amixture of pyrolysis oil and biogas in the following two ways: (i)autothermal reforming of pyrolysis oil and biogas, in which thereare two reactions in one reactor (ATR) and (ii) steam reforming ofpyrolysis oil and catalytic partial oxidation of biogas, in whichthere are separated but thermally coupled reactions and reactors (CR).The other two steps to produce methanol from syngas, and gasolinefrom methanol, remain the same. The purpose of this simulation isto have an ex-ante comparison of the performance of the new routesagainst a reference, in terms of energy and sustainability. Thus,at this stage of simulations, nonrigorous, equilibrium-based modelshave been used for reactors, which will give the best case conversionsfor each step. For the conventional production route, conversion andyield data available in the literature have been used, wherever available.Theresults of the process design showed that the second method (separate,but thermally coupled reforming) has a carbon efficiency of 0.53,compared to the conventional route (0.48), as well as the first route(0.40). The life-cycle assessment results revealed that the newlyproposed processes have a clear advantage over the conventional processin some categories, particularly the global warming potential andprimary energy demand; but there are also some in which the conventionalroute fares better, such as the human toxicity potential and the categoriesrelated to land-use change such as biotic production potential andthe groundwater resistance indicator. The results confirmed that eventhough using biomass such as timber pine as raw material does resultin reduced greenhouse gas emissions, the activities associated withbiomass, such as cultivation and harvesting, contribute to the environmentalfootprint, particularly the land use change categories. This givesan impetus to investigate the potential of agricultural, forest, oreven food waste, which would be likely to have a substantially lowerimpact on the environment. Moreover, it could be seen that the sourceof electricity used in the process has a major impact on the environmentalperformance.

No MeSH data available.