UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

Super Critical Water Gasification of Biomass

Kenneth Faires andJoyce Cooper Design for Environment LabDepartment of Mechanical EngineeringUniversity of Washington

UWME DFE Lab: http://faculty.washington.edu/cooperjs/

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

Super Critical Water Gasification of Biomass

The OpportunitySeveral 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.

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

Super Critical Water Gasification of Biomass

Current resourcesFunding 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.

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

UW BioResources IGERTThe 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 agricultural activities)

the processing of materials and fuels

technology design and manufacturing

technology use and maintenance

technology retirement and remanufacturing

the ultimate management of materials (e.g., recycling,

landfilling, and incineration) Plus energy production and transport throughout

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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?

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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.

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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:

CHxOy + (1-y) H2O → CO + (x/2 +1-y)H2

CO + H2O → CO2 + H2

CO + 3H2 → CH4 + H2O

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, 2410-2415

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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 700-800K at pressures near 25 MPaAdvantages

Gas produced is “water scrubbed” which equates to a high quality productCatalysts are not necessaryA large variety of biomass can be used, and it does not need to be pre-driedThe economics are promising

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

SCWG Economics are Promising

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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 AnalysisBatch 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)

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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 systemsContribute 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.

Feed/HopperPressure Tank

Throttle Valve

Liquid/ Gas Separation

Proposedexperimental setup

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

The Feed HopperHeated 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

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

The Pressure TankDual Pressure Tanks with pneumatic hydraulic drive separated individually from hopper via stainless steel Globe Valves

Each tank connects to a Y junctionWith individual check valves to Prevent backflow

Inner Dia 2” length 12” 304ss

Hydraulic Ram

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

The Y Coupler/Active CoolingBy 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

Flow from Pressure Tanks

Holes for cooling water circulation

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

The ReactorExisting 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, 12.7mmReactor of Inconel 12” longWith thermocouples/pressureGauges every 3”

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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

OutIN

SS needle valve to be used to throttle Gases/exhaust to ambient pressure

Water bath used to separate gas and liquid phasesWater is recirculated to preheat hopper and pressure tanks

To gas analyzer

Recirc toHopper/Tanks

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

Syngas and Waste Water Constituents

SyngasDetermine the presence/ concentrations of: CO, CO2, H, CH4, and sulfur

Waste water Determine the presence/ concentrations of: sulfur, benzene, tar, heavy metals (As, Hg, Pb, etc.), silicon, chlorine, ammonia, and HCN

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

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)

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

Areas Utilizing CPAC Expertise

Liquid/Gas Separator – Testing water for byproductsGas Analyzer – best setup for testing syngas(types, quality, volume, etc) Syngas Vent/Application

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

Updates

Engaged APL researchersBrian J. Marquardt Ph.D., Senior EngineerInvestigating the possibility of In-Situ testing via Raman Spectroscopy

Engaged Pacific National Labs researchersObserved equipment setup and experimentation used in Sub-critical pressurized water systems

Started hardware production

UWME Design for Environment Lab Assessing the life cycle environmental aspects of emerging technologies

Questions?