Reducing PM Concentrations in Simulated High Temperature Gas Streams

The goal of this research is to use the energy in cotton gin trash (CGT) to fuel an internal combustion engine (ICE) driving a generator to produce electricity for a cotton gin. CGT is a fuel that has char that melts at low temperatures. This characteristic is referred to as char having a low eutectic point. Biomasses with low eutectic points cannot be used in a combustion process because the char will result in slagging and fouling. We have used fluidized bed gasification (FBG) to control the reaction temperatures and capture the energy in the biomass. CGT has an approximant 16,300 kJ/kg (7,000 Btu/lb) of energy. The resulting synthetic gas (syngas) can have an energy content as high as 7,450 kJ/m^(3) (200 Btu/dscf) and can be fed directly into an internal combustion engine (ICE) which can drive a generator to produce electricity. The syngas conveys the char from the bed to the gas cleanup system consisting of specially designed cyclones. The cyclones were used to reduce particulate matter (PM) concentrations in the syngas prior to delivery to the ICE. Cyclones are capable of reducing the concentrations of particulate matter from syngas streams. The temperatures of the syngas leaving the gasification bed ranges from 371 to 760 ?C (700 to 1400 ?F). These high temperatures impact the cyclone inlet velocities as a consequence of the reduced gas densities. Changes in gas densities will influence the cyclone design. It was hypothesized that changes in cyclone performances as a consequence lower gas densities could be approximated by increasing the cyclones inlet velocities of air at standard temperature and pressure (STP) to correspond to the anticipated cyclone?s inlet velocities of syngas at the higher temperatures. Multiple tests of cyclone performances in simulated high temperature gas streams were conducted using bio-char. Preliminary cyclone testing results indicate that the location of the vortex inverter in the cyclone relative to the natural length can significantly impact the cyclone performance and design. Tests were conducted at inlet velocities of 16.3, 30.5, and 45.7 m/s (3,000, 6,000 and 9,000 fpm). Increasing inlet velocities resulted in increasing the cyclone?s natural length. This study was limited to testing cyclone performances at ambient temperatures and simulating high temperature airflow rates and velocities for safety purposes. Natural lengths were used to help determine the optimum location of the vortex inverter; resulting in a new design process for cyclones operating with high temperature gases.