Feedstock Quality Factor Calibration and Data Model Development

Abstract

Objective:The goal of the feedstock assembly operation is to deliver uniform, quality-assured feedstock materials that will enhance downstream system performance by avoiding problems in the conversion equipment. In order to achieve this goal, there is a need for rapid screening tools and methodologies for assessing the thermochemical quality characteristics of biomass feedstock through the assembly process. Laser-induced breakdown spectroscopy (LIBS) has been identified as potential technique that could allow rapid elemental analyses of the inorganic content of biomass feedstocks; and consequently, would complement the carbohydrate data provided by near-infrared spectrometry (NIRS). These constituents, including Si, K, Ca, Na, S, P, Cl, Mg, Fe and Al, create a number of downstream problems in thermochemical processes. In particular, they reduce the energy content of the feedstock, influence reaction pathways, contribute to fouling and corrosion within systems, poison catalysts, and impact waste streams. Expected Outcome:The mineral content and composition is recognized as both a barrier to the use of some feedstocks and as a quality attribute that may be controlled through the feedstock assembly process. The inorganic content of biomass feedstocks is known to vary over wide ranges, depending upon the plant type and anatomical fraction, growing conditions, harvesting time and method, and handling operations. If this task is successful in developing a cost-effective screening tool, there may be opportunities for selecting and blending diverse feedstocks to produce on-spec materials that will in turn, reduce the capital and maintenance costs associated with syngas cleaning and replacing components in conversion platforms. Progress:Scoping studies have been conducted with the instrumentation in order to establish the feasibility of using the LIBS technique as a feedstock screening tool and to determine the optimal system operational parameters. These parameters include identifying the most sensitive, interference-free analytical lines for key elements and the laser ablation pulse parameters for sampling the materials. The sensitivity of the analytical lines to changes in elemental concentrations over ranges of interest has been benchmarked against independent analytical analyses conducted by Hazen Research Inc.