Southern Research has an established reputation as a worldwide leader in hot-gas filtration based on our extensive accomplishments and expertise in this area, including:

• Developers of first reliable method for hot-gas filter sizing
• Based on fundamental characteristics of gasification ash
• Validated based on actual hot-gas filter performance data
• Developers of first HTHP in-situ sampling systems for filter evaluations
• One-of-a-kind, proven system for evaluating hot-gas filters
• Measures outlet particle loadings as low as 0.1 ppmw
• Provides representative filter inlet samples for particle characterization
• Experts in ash/char characterization
• Relating ash/char characteristics to filter pressure drop
• Assessing potential for ash/char bridging and blinding
• Experts in real-time monitoring of filter performance
• Developed unique HTHP particle extraction and sampling system
• Coupled with most sensitive single-particle counter available

In situ Particulate Sampling

Unique capabilities at Southern Research include one-of-a-kind systems for in situ particulate sampling in high-temperature, high-pressure gas streams. These systems, which were designed and built by Southern Research, have been in operation at the Power Systems Development Facility since 1996 and have operated with nearly 100% availability. (View paper)

Simulation of Dustcake Flow Resistance

Additional unique equipment available at Southern Research includes a custom-built system for resuspending and collecting dust particles under conditions that simulate their collection in the hot-gas filter. The system includes provisions for various cyclone configurations to adjust the particle-size distribution of the dust being collected. Using this apparatus, the dustcake drag can be evaluated over a range of particle sizes and flow conditions. (View paper)

Performance Analysis and Filter Sizing

Based on laboratory drag measurements and information from particulate sampling, Southern Research is developing and validating new procedures for the analysis of filter performance and sizing of new hot-gas filters. These procedures clearly show the critical importance of dustcake drag in determining filter performance and the required size of new filters. (View paper)

Multi-Pollutant Gas Cleaning

Building on our experience and expertise in hot-gas filtration, Southern Research is exploring various concepts for multi-pollutant control based on the use of hot-gas filters. Two such concepts are illustrated below. In these systems, various sorbents are used to remove sulfur species and trace metals. The sorbents form a reactive cake on the filter elements, which also contain catalysts for cracking tars and ammonia. This type of system allows the simultaneous removal of particulates, sulfur species, trace metals, ammonia, and tar in a single vessel. In addition, the system may be coupled directly or indirectly to a gasifier, as illustrated below.

Advantages of the multi-pollutant control system include:

• Utilizes proven filter concept developed by Pall Corporation to crack tars and NH₃
• Kaolinite-type sorbent and calcium-based sorbent can be fed separately or with fuel
• Installation in freeboard can eliminate need for a separate filter vessel
• System can achieve very low levels of trace metal, sulfur, tar, and NH₃ contaminants
• Minimal "polishing" cleanup required
• Compatible with requirements for fuel cell, F-T, and gas separation membranes
• Capture of trace metals prevents poisoning of tar- and ammonia-cracking catalysts
• Inexpensive kaolinite-containing waste materials are available from paper mills
• For example, decarbonized, de-inking sludge (50% kaolinite)
• Various inexpensive sources of calcium-based sorbent are available
• Limestone, lime, hydrated lime, and paper recycling waste