(483f) Promoting Efficient Adsorbent Bed Operation through Direct in-Situ Monitoring for Desulfurization of Distributed Energy Resources

Authors: 
Dimick, P. S., IntraMicron, Inc.
Yang, H., IntraMicron, Inc.
Williams, T., IntraMicron, Inc.
Milton, S., IntraMicron, Inc.
Webb, K., IntraMicron, Inc.
Neumann, T., North Carolina State University
Tatarchuk, B., IntraMicron, Inc.

Distributed energy resources such as biogas, landfill gas, and flare gas are becoming increasingly important alternative energy resources; however, many of these resources cannot be economically produced due to high gas cleanup costs with the majority of these costs coming from desulfurization. Due to the small size and distributed nature of these resources, adsorption remains the most common desulfurization technology for these applications, particularly where sulfur loads are less than 100 kg per day. Adsorption-based desulfurizers are typically designed and operated assuming they will continuously experience the maximum possible inlet sulfur concentration.  During actual operation, the inlet sulfur concentration often fluctuates at levels lower than the design criteria.  When this occurs and the adsorbent is replaced or regenerated at pre-determined intervals, a large portion of the bed is never utilized, resulting in significant waste and inefficient operation.  While complicated systems that require  analytical equipment (e.g. an online GC), continuous gas concentration monitoring, and a full understanding of the adsorbent’s performance have been proposed to predict bed performance, it is not practical or economical to apply these solutions for small-scale applications.  IntraMicron has addressed the issue of efficiently determining when to replace or regenerate an adsorbent bed with its bed life capacity sensor (BLS) which directly monitors adsorbent bed saturation.  The BLS is based on spectroscopic techniques which are commonly used for adsorbent and catalyst characterization. These techniques that have been applied and extended to reliably determine bed saturation and to predict appropriate adsorbent replacement or regeneration timing.   It has been demonstrated that this technology is effective for both IntraMicron-proprietary and other commercially available adsorbents. Furthermore, this technology is not significantly affected by the presence of common contaminants and/or competitive adsorbates.  Since the BLS directly monitors adsorbent saturation, it is compatible with fluctuating inlet sulfur concentrations and does not require monitoring gas-phase sulfur levels with high-maintenance analytical equipment.  The BLS allows maximum adsorbent utilization between adsorbent replacements or regenerations significantly reducing the waste-generation and OPEX of adsorption-based desulfurization systems. While the BLS is a stand-alone technology, it is commonly used within IntraMicron’s Desulfurization Technology Suite (IM-DTS) for optimal desulfurization performance. IM-DTS is an economical, low-waste, environmentally-friendly sulfur removal and recovery system targeted at small-scale energy resources.
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