Super Critical Water Gasification of Biomass

Transcription

1 Super Critical Water Gasification of Biomass Kenneth Faires and Joyce Cooper Design for Environment Lab Department of Mechanical Engineering University of Washington UWME DFE Lab:

2 Super Critical Water Gasification of Biomass The Opportunity Several technologies are currently emerging to convert woody biomass to energy. Although conventional gasification allows for the use of a variety of biomass types, reliability issues persist. Suggested solutions include supercritical water gasification (SCWG), which has the potential to produce high-quality syngas using a wide range of wood and other feedstocks.

3 Super Critical Water Gasification of Biomass Current resources Funding and the faculty and students involved in the UW BioResource IGERT $3M from the National Science Foundation s Integrative Graduate Education and Research Traineeship (IGERT) program provides both the funding and multidisciplinary expertise to integrate considerations of energy security, rural development, and a better environment into technology R&D.

4 UW BioResources IGERT The UW IGERT program is founded in the idea that new research opportunities lie at the intersection of resource management practices, molecular science and engineering, and Life Cycle Assessment (LCA) strategies. LCA is a model-based approach for assessing where, and in what form, energy and materials are used (and wasted) throughout the technology life cycle. the acquisition of materials and fuels (e.g., mining, forest harvest, and the ultimate management of materials (e.g., recycling, landfilling, and incineration) technology retirement and remanufacturing agricultural activities) Plus energy production and transport throughout technology use and maintenance the processing of materials and fuels technology design and manufacturing

5 What does Life Cycle Assessment measure? LCA can be used to measure the broader impacts of decisions, in the three categories of sustainability Environmental impacts Business impacts Social impacts Contribution to global warming, acidification, smog, toxic impacts, landuse changes. Materials management, monitoring, business disruption, training & personnel protection, brand equity Job creation, employee treatment/ satisfaction, community service, international resources Where does SCWG fit in?

6 Where does SCWG fit in? SCWG itself promises to be an important technology supporting current biomass-to-energy efforts for reductions in fossil fuel consumption and climate change emissions. Considering life cycle environmental, economic, and social impacts during the further development of SCWG promises to optimize systems for wide-scale dissemination with VERY broad and VERY positive impact. Further, our view differs from that of other SCWG researchers: whereas much of the current efforts have focused on the chemical engineering aspects of SCWG, we are focusing on how the principles of mechanical engineering can afford reliability improvements and scalability.

7 What is Super Critical Water Gasification? SCWG is a form of gasification in which a reactor is pressurized and the temperature balanced such that the water within the biomass is at its critical point, proceeding as: CH x O y + (1-y) H 2 O CO + (x/2 +1-y)H 2 CO + H 2 O CO 2 + H 2 CO + 3H 2 CH 4 + H 2 O and proven for tobacco stalk, corn stalk, cotton stalk, sunflower stalk, corncob, oreganum stalk, chromium-tanned waste, and vegetable-tanned waste BUT NOT WITHOUT ISSUES AUTHORS (2007) Biomass Gasification in SCW: Part 1. Effect of the nature of biomass, Fuel, 86,

8 What is Super Critical Water Gasification? SCWG is ideal for wet biomass containing as much as 90% water and yielding a carbon build-up to <5%. Temperatures can range from 650k to 1000k with pressures on the order of 20-35MPa, although typical temperatures are K at pressures near 25 MPa Advantages Gas produced is water scrubbed which equates to a high quality product Catalysts are not necessary A large variety of biomass can be used, and it does not need to be pre-dried The economics are promising

9 SCWG Economics are Promising

10 Previous Research and the Opportunity for the UW Although the process has been demonstrated in the laboratory and in pilot applications and the governing mechanisms have been described, no research is available on the relationships between hardware design and fuel composition and performance, syngas quality, reliability, and scalability. Thermodynamic Modeling and Analysis Batch research to demonstrate scope of applicability (i.e. material types/water contents) Attempts at flow reactor runs (unsuccessful on actual biomass coking clogs the reactor in less than 1hr)

11 SCWG of Biomass: Project Goals Develop the capacity to perform experimental investigations of fuel and hardware performance for supercritical water gasification, and at the same time Integrate design, performance, reliability, and scalability analyses into Life Cycle Assessments of supercritical water gasification systems Contribute not only to the development of this technology but also to Life Cycle Assessment methodology (particularly related to the integration of reliability analysis). Set the stage for future research by UW PhDs/ IGERT Fellows.

12 Feed/Hopper Pressure Tank Throttle Valve Liquid/ Gas Separation Proposed experimental setup

13 The Feed Hopper Heated feed hopper filled with water (in order to saturate biomass (temp approx 100C) Possibility of pressurizing via sealing (such as in a pressure cooker) or using air to aid in filling tanks

14 The Pressure Tank Dual Pressure Tanks with pneumatic hydraulic drive separated individually from hopper via stainless steel Globe Valves Hydraulic Ram Each tank connects to a Y junction With individual check valves to Prevent backflow Inner Dia 2 length ss

15 The Y Coupler/Active Cooling By utilizing an active fluid flow to cool the Y coupler connecting the feed tanks to the reactor a thermal barrier can be created in order to study and possibly mediate effects of coking due to thermal gradients Flow to Reactor Holes for cooling water circulation Flow from Pressure Tanks

16 The Reactor Existing research has suggests Nickel as use for a catalyst. Due to high temperature and pressure Inconel is an ideal material. This has the possible added benefits of catalyzing. Additionally rifling will be used to increase surface area and give bleed channels for coking. Rifled 6mm, 9mm, 12.7mm Reactor of Inconel 12 long With thermocouples/pressure Gauges every 3

17 The Throttle Valve & Liquid Gas Separator Previous experiments have used a series of fine holes and or needle vales in order to throttle gases to ambient. By recirculating the water the advantage of heat exchange is obtained while retaining water for testing/conservation SS needle valve to be used to throttle Gases/exhaust to ambient pressure IN Out To gas analyzer Recirc to Hopper/ Tanks Water bath used to separate gas and liquid phases Water is recirculated to preheat hopper and pressure tanks

18 Using the Syngas For syngas use, there has been discussion of use in SOFC, small turbines, or possible venting Options introduce syngas requirements, coupled with wastewater management concerns

19 Syngas and Waste Water Constituents Syngas Determine the presence/ concentrations of: CO, CO 2, H, CH 4, and sulfur Waste water Determine the presence/ concentrations of: sulfur, benzene, tar, heavy metals (As, Hg, Pb, etc.), silicon, chlorine, ammonia, and HCN

20 Gas Analyzer System and Syngas Vent Previous researchers have used HP5889A gas chromatographs & HP6890 chromatographs for analysis of the syngas. Rosemount Dohrmann DC190 used for aqueous phase (found furfurals and hydroxyacedic acid)

21 Areas Utilizing CPAC Expertise Liquid/Gas Separator Testing water for byproducts Gas Analyzer best setup for testing syngas (types, quality, volume, etc) Syngas Vent/Application

22 Updates Engaged APL researchers Brian J. Marquardt Ph.D., Senior Engineer Investigating the possibility of In-Situ testing via Raman Spectroscopy Engaged Pacific National Labs researchers Observed equipment setup and experimentation used in Sub-critical pressurized water systems Started hardware production

23 Questions?