Direct Liquefaction of Biocoals as a Sustainable Route to Second-Generation Biofuels

Transcription

1 Direct Liquefaction of Biocoals as a Sustainable Route to Second-Generation Biofuels Martin Trautmann, Swen Lang, Armin Löwe, Yvonne Traa Institute of Chemical Technology, University of Stuttgart, Germany INSTITUTE OF CHEMICAL TECHNOLOGY

2 Production of Second-Generation Biofuels First-generation biofuels, such as ethanol and biodiesel, are made from sugars or vegetable oils. Second-generation biofuels or advanced biofuels are made from lignocellulosic biomass or woody crops, agricultural residues or waste, and are thus less interfering with food supplies and biodiversity. 2 M. Trautmann, A. Löwe, Y. Traa, Green Chem. 16 (2014) 3710.

3 Direct Coal Liquefaction 2.5 H / C molar ratio Gasoline Synthesis gas Diesel Coal Average carbon number Y. Traa, Chem. Commun. 46 (2010) 2175.

4 Direct Biocoal Liquefaction 4 M. Trautmann, A. Löwe, Y. Traa, Green Chem. 16 (2014)

5 Hydrothermal Carbonization of Biomass The patented CarboREN technology from SunCoal Industries homogenizes biomass to biocoal, which is then dried. Using this process, damp biomass with 20 75% water content and a low heating value is converted to biocoal which has similar characteristics as fossil coal. The CarboREN technology requires only a minimal amount of energy (7% of the energy of the produced biocoal) and is designed in modular units to be constructed according to customer needs. 5 A wide variety of organic waste materials can be used.

6 1. Introduction Outline 2. Direct Coal Liquefaction in Practice 3. Results and Discussion 4. Conclusions and Outlook 6

7 Shenhua: Direct Coal Liquefaction Two ebullated bed reactors utilising a proprietary dispersed superfine (nanosized) disposable Fe catalyst (GelCat) prepared from iron sulfate. Fixed-bed in-line hydrotreater with Ni-Mo/Al 2 O 3 catalyst. Feedstock: Bituminous fossil coal. Reaction conditions: 400 to 460 C, 17 MPa hydrogen. July 2011: 12 times of coal injection completed 10,670 operating hours products: 550,000 t diesel 247,500 t naphtha 7 99,000 t LPG

8 Simplified Scheme of Direct Coal Liquefaction 8 Y. Traa, Chem. Commun. 46 (2010) 2175.

9 Experimental Setup Technical data: Parr MiniBench Top Reactor 4570 Reactor volume: 250 ml Maximum pressure: 34.5 MPa Maximum temperature: 773 K Typical reaction conditions: 9 T = K, p H2,cold = 10 MPa, m tetralin /m maf coal = 1, reaction time 1 h p H2, hot = MPa.

10 Definitions of Direct Coal Liquefaction Oil: Primary liquefaction products which are soluble in n-pentane (C 5 -C n hydrocarbons). Gas phase: Organic (C 1 -C 4 hydrocarbons) and inorganic gases from liquefaction (H 2 O, NH 3, H 2 S). Residue: Unconverted coal. Asphaltenes: Further liquefaction products soluble in benzene, but insoluble in n-pentane. Preasphaltenes: Further liquefaction products soluble in pyridine, but insoluble in benzene. 10 Coal conversion: Only oil and gas phase are considered as converted mass (related to the maf = moistureand ash-free coal).

11 Results of Direct Biocoal Liquefaction 11 M. Trautmann, S. Lang, Y. Traa, revised version submitted for publication in Fuel.

12 Quality of the Biooils 12 M. Trautmann, S. Lang, Y. Traa, revised version submitted for publication in Fuel.

13 Biopetroleum? H/C molar ratio Standard: biopetroleum Biomass liquefaction oil Biooil after pyrolysis and HDO Our biooil > HHV / MJ kg -1 > Oxygen content / wt.-% < HHV = Higher Heating Value: Amount of heated released during combustion. 13 C. Wang, J. Pan, J. Li, Z. Yang, Bioresource Technol., 99 (2008) M. Trautmann, A. Löwe, Y. Traa, Green Chem. 16 (2014) 3710.

14 Simplified Scheme of Direct Coal Liquefaction 14 Y. Traa, Chem. Commun. 46 (2010) 2175.

15 Considerations for the Second Stage Hydrotreating of the oils using hydrogen and typical catalysts active for hydrodeoxygenation (HDO). Co-processing in Fluid Catalytic Cracking Units. Selective ring opening of aromatic rings to diesel fuel. Tailoring of the second stage for the envisaged application 15

16 Greener Alternatives for Hydrogen Production Natural gas (CH 4 ) or mixtures of CH 4 and H 2 can be used as hydrogenation gas. Liquefaction of brown coal with NaOH/MeOH at 300 C + 13 MPa; MeOH, CaO, FeS at 400 C + 4 MPa. Liquefaction in CO/H 2 O: CO + H 2 O CO 2 + H 2. Hydrogen can be produced by water electrolysis using excess energy from wind or sun. 16 Hydrothermal gasification: Wet biomass is gasified at temperatures up to 873 K yielding H 2 + CO 2. A pilot plant has already shown to be feasible by producing up to 83 vol.-% H 2 in the product at a high thermal efficiency.

17 Conclusions and Outlook Direct liquefaction of biocoals produced by hydrothermal carbonization from green waste is possible. Biooils thus produced are a good starting point for further upgrading to tailored fuel products. 17 The carbon footprint is reduced by using the produced biooils. However, further investigations and investment are necessary: i. Valuable hydrogen is consumed to produce water from oxygen in the biomass: Green hydrogen production necessary. ii. iii. iv. Biooil yields and catalysts have to be improved. Biooil upgrading has to be developed.

18 THE END!!! THANK YOU FOR YOUR ATTENTION!!! 18