Gate-to-gate GHG emissions for carbon activation of biochar

Transcription

1 Gate-to-gate GHG emissions for carbon activation of biochar Hongmei Gu and Rick Bergman US Forest Products Laboratory Madison, WI, USA 2016 Society of Wood Science and Technology, March 6-11, 2016 Curitiba, Brasil

2 Presentation overview A. Overall project Process chain for woody biomass to bioenergy/bio-product conversion B. LCA on carbon activation from biochar and coal 1. Goal and scope of LCA 2. Process flows 3. Results and comparison 4. Conclusions 2

3 Overall project: Biomass Research Development Initiatives (BRDI) -- Integration of Biofuels and Bioproducts Production into Forest Products supply Chains using Modular Biomass Gasification and Carbon Activation Technical Area 3: Biofuels development analysis 1. Find GHG emissions and mass and energy balances for the Tucker renewable natural gas (RNG) unit 2. Evaluate the impacts for forest biomass utilization 3. Develop financial models for biomass on economic conditions in the US West 4. Develop an economic synthesis of modular gasification at forest industry facilities 3

4 Overall Project -- Process Chain State and National forest management Forest residue biomass extraction Sawmill chip processing Syngas electricity generation Biochar carbon activation Tucker RNG (thermochemical) conversion unit 4

5 Biomass System Chain Upstream: forest management, log extraction, chip production Midstream: advanced pyrolysis Downstream: syngas to electricity, biochar to activated carbon Gate-to-gate GHG emissions for carbon activation of biochar 5

6 Carbon activation system Physical activation with heat and steam (our process) Chemical activation with impregnation of agents Source: Rodriguez-Reinoso F (2002) Production and applications of activated carbons. Figure 9.1: General flow for the manufacture of activated carbon. In: Handbook of Porous Solids. Eds. Schuth F, Sing KSW, Weitkamp J. Wiley-VCH Verlag GmmH, Weinheim, Germany, pp

7 Life cycle analysis LCA calculates all kinds of environmental impacts (carbon footprint, energy, water, acidity, toxicity, etc.) for a product or service across the entire life cycle from raw material extraction, to product making, to distribution, use, and end of life. 7

8 Scope of LCA project Unit process modeling Gate-to-gate Define the system boundary What flows in and out is accounted for Select functional unit 1 kg of activated carbon (AC) 8

9 System boundary 9

10 Inputs compared with coal AC Tucker biochar AC Hard coal AC #1 Hard coal AC #2 Product 1 kg AC 1 kg AC 1 kg AC Feedstock 2.11 kg 3 kg 2 kg Natural gas 3 m m 3 (steam heating only) 4.9 m 3 Steam 2.11 kg 12 kg 3 kg Electricity 3.78 kwh 1.6 kwh kwh Nitrogen kg?? n/a Washing with HCl n/a?? 0.04 kg Hard coal AC #1: Bayer, et al. (2005). Economical and ecological comparison of granular activated carbon (GAC) adsorber refill strategies. Waste Research 39: Hard coal AC #2: Meier M A. (1997). Eco-efficiency evaluation of waste gas purification systems in the chemical industry. Doctoral thesis. Swiss Federal Institute of Technology Zurich. Diss. ETH No

11 Results compared to coal Activated C Type of activated carbon Cumulativ e Energy (MJ) Yield (%) GHG (CO2eq kg) Sustainability Impact to Feedstock Ecology Renewability Tucker biochar AC % 9.18 wood chips low yes Hard coal AC # % 9.20 coal high no Hard coal AC # % coal high no 11

12 Activated carbon from managed forest residues is a superior substitute to coal AC: Less energy consumption for activation; Reduce GHG emissions; Renewable; Conclusions Low on ecological impact (under further investigation) Physical properties of biochar AC have similar properties to coal AC on the market (Dr. Nate Anderson) 12

13 Future analysis More environmental impact categories than GHG; Add up-stream environmental impacts and compared with coalderived AC; Physical properties of biochar AC vs coal AC for markets. 13

14 Acknowledgement This project was supported by the Agriculture and Food Research Initiative, Biomass Research and Development Initiative, Competitive Grant no from the USDA National Institute of Food and Agriculture. 14

15 Questions? Hongmei Gu (608) Rick Bergman (608)