While thermochemical syngas production facilities for biomass utilization are already employed worldwide, exploitation of their potential has been inhibited by technical limitations encountered when attempting to obtain real-time syngas compositional data required for process optimization, reliability, and syngas quality assurance. To address these limitations, the Gas Technology Institute (GTI) carried out two companion projects (under US DOE Cooperative Agreements DE-FC36-03GO13175 and DE-FC36-02GO12024) to develop and demonstrate the equipment and methods required to reliably and continuously obtain accurate and representative on-line syngas compositional data. These objectives were proven through a stepwise series of field tests of biomass and coal gasification process streams. GTI developed the methods and hardware for extractive syngas sample stream delivery and distribution, necessary to make use of state-of-the-art on-line analyzers to evaluate and optimize syngas cleanup and conditioning. This multi-year effort to develop methods to effectively monitor gaseous species produced in thermochemical process streams resulted in a sampling and analysis approach that is continuous, sensitive, comprehensive, accurate, reliable, economical, and safe. The improved approach for sampling thermochemical processes that GTI developed and demonstrated in its series of field demonstrations successfully provides continuous transport of vapor-phase syngas streams extracted from the main gasification process stream to multiple, commercially available analyzers. The syngas stream is carefully managed through multiple steps to successfully convey it to the analyzers, while at the same time bringing the stream to temperature and pressure conditions that are compatible with the analyzers. The primary principle that guides the sample transport is that throughout the entire sampling train, the temperature of the syngas stream is maintained above the maximum condensation temperature of the vapor phase components of the conveyed sample gas. In addition, to minimize adsorption or chemical changes in the syngas components prior to analysis, the temperature of the transported stream is maintained as hot as is practical, while still being cooled only as much necessary prior to entering the analyzer(s). The successful transport of the sample gas stream to the analyzer(s) is accomplished through the managed combination of four basic gas conditioning methods that are applied as specifically called for by the process conditions, the gas constituent concentrations, the analyzer requirements, and the objectives of the syngas analyses: 1) removing entrained particulate matter from the sample stream; 2) maintaining the temperature of the sample gas stream; 3) lowering the pressure of the sample gas stream to decrease the vapor pressures of all the component vapor species in the sample stream; and 4) diluting the gas stream with a metered, inert gas, such as nitrogen. Proof-of-concept field demonstrations of the sampling approach were conducted for gasification process streams from a black liquor gasifier, and from the gasification of biomass and coal feedstocks at GTI’s Flex-Fuel Test Facility. In addition to the descriptions and data included in this Final Report, GTI produced a Special Topical Report, Design and Protocol for Monitoring Gaseous Species in Thermochemical Processes, that explains and describes in detail the objectives, principles, design, hardware, installation, operation and representative data produced during this successful developmental effort. Although the specific analyzers used under Cooperative Agreement DE-FC36-02GO12024 were referenced in the Topical Report and this Final Report, the sampling interface design they present is generic enough to adapt to other analyzers that may be more appropriate to alternate process streams or facilities.
