Equilibrium chemistry of biomass combustion: A round-robin set of calculations using available computer programs and databases

Equilibrium calculations of three problems regarding biomass combustion, at various levels of sophistication, were performed at six laboratories using seven combinations of computer programs and databases. The objective was t o test the adequacy of the programs and databases for calculating both cond ensed and gas-phase behavior. The first problem was a simplified calculatio n for the combustion of a woodlike material with added sulfur to possibly f orm an ideal molten salt solution of potassium and calcium sulfate. The sec ond and third problems were to simulate aspen wood and wheat straw combusti on, respectively, and required a relatively sophisticated database on high- temperature solutions to describe condensed phases. All the participants pe rformed calculations of the gas phases, which were reasonably accurate when their databases were adequate. For problem I, most of the participants wer e also able to calculate a reasonable set of condensed phases. However, for problems II and III, only four of the participants, using the two most Sop histicated computer programs and databases, had the ability to produce rati onal results for the condensed phases. This round robin identified two comp uter programs and their associated databases that could prove useful for ca lculating the condensed-phase equilibrium chemistry of biomass combustion w hen coupled with experimental programs and the capability to expand databas es as new experimental data become available. Such calculations can greatly enhance our understanding of the total equilibrium chemistry of biomass co mbustion.