Vladimir Zamansky

FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

GE Global Research is developing an innovative energy technology for coal gasification with high efficiency and near-zero pollution. This Unmixed Fuel Processor (UFP) technology simultaneously converts coal, steam and air into three separate streams of hydrogen-rich gas, sequestration-ready CO{sub 2}, and high-temperature, high-pressure vitiated air to produce electricity in gas turbines. This is the draft final report for the first stage of the DOE-funded Vision 21 program. The UFP technology development program encompassed lab-, bench- and pilot-scale studies to demonstrate the UFP concept. Modeling and economic assessments were also key parts of this program. The chemical and mechanical feasibility were established via lab and bench-scale testing, and a pilot plant was designed, constructed and operated, demonstrating the major UFP features. Experimental and preliminary modeling results showed that 80% H{sub 2} purity could be achieved, and that a UFP-based energy plant is projected to meet DOE efficiency targets. Future work will include additional pilot plant testing to optimize performance and reduce environmental, operability and combined cycle integration risks. Results obtained to date have confirmed that this technology has the potential to economically meet future efficiency and environmental performance goals.

Advances in the development of wire mesh reactor for coal gasification studies.

In an effort to further understand the coal gasification behavior in entrained-flow gasifiers, a high pressure and high temperature wire mesh reactor with new features was recently built. An advanced LABVIEW-based temperature measurement and control system were adapted. Molybdenum wire mesh with aperture smaller than 70 mum and type D thermocouple were used to enable high carbon conversion (>90%) at temperatures >1000 degrees C. Gaseous species from wire mesh reactor were quantified using a high sensitivity gas chromatography. The material balance of coal pyrolysis in wire mesh reactor was demonstrated for the first time by improving the volatiles quantification techniques.

Optimization of advanced reburning via modeling

The advanced reburning (AR) process is an integration of basic reburning and N-agent injection. The efficiency of AR depends on many factors, including the amount of the reburning fuel, the amount and location of N-agent injection, and spray characteristics. These parameters can be optimized via computer modeling. This paper describes a model that combines a detailed chemical mechanism with a simplified representation of mixing to describe the AR-lean process, a combination of basic reburning and N-agent coinjection with overfire air (OFA). The model takes into account mixing and thermal characteristics of a 300 KW combustion facility, which was used for experimental studies in support of model development. Modeling suggested that the efficiency of AR-lean strongly depends on amounts of the reburning fuel and N-agent, flue gas temperature at the point of OFA/N-agent injection, and N-agent evaporation time. The model described the most important features of AR-lean. Application of the model for optimization of AR-lean performance in the test facility was demonstrated.

MINIMIZATION OF CARBON LOSS IN COAL REBURNING

This project develops Fuel-Flexible Reburning (FFR), which combines conventional reburning and Advanced Reburning (AR) technologies with an innovative method of delivering coal as the reburning fuel. The overall objective of this project is to develop engineering and scientific information and know-how needed to improve the cost of reburning via increased efficiency and minimized carbon in ash and move the FFR technology to the demonstration and commercialization stage. Specifically, the project entails: (1) optimizing FFR with injection of gasified and partially gasified fuels with respect to NO{sub x} and carbon in ash reduction; (2) characterizing flue gas emissions; (3) developing a process model to predict FFR performance; (4) completing an engineering and economic analysis of FFR as compared to conventional reburning and other commercial NO{sub x} control technologies, and (5) developing a full-scale FFR design methodology. The project started in August 2000 and will be conducted over a two-year period. The work includes a combination of analytical and experimental studies to identify optimum process configurations and develop a design methodology for full-scale applications. The first year of the program included pilot-scale tests to evaluate performances of two bituminous coals in basic reburning and modeling studies designed to identify parameters that affect the FFR performance and to evaluate efficiency of coal pyrolysis products as a reburning fuel. Tests were performed in a 300 kW Boiler Simulator Facility to characterize bituminous coals as reburning fuels. Tests showed that NO{sub x} reduction in basic coal reburning depends on process conditions, initial NO{sub x} and coal type. Up to 60% NO{sub x} reduction was achieved at optimized conditions. Modeling activities during first year concentrated on the development of coal reburning model and on the prediction of NO{sub x} reduction in reburning by coal gasification products. Modeling predicted that composition of coal gasification products depends on gasification temperature. At lower temperature yield of hydrocarbons is high which results in higher efficiency of NO{sub x} control. As temperature decreases, yield of hydrocarbons increases and CO and H{sub 2} yields decrease.