Partitioning of inorganic elements in pilot-scale and demonstration-scale entrained-flow gasifiers

The integrated gasification combined cycle (IGCC) has been recognized as one of the leading methods of power generation with near zero CO2 emissions from fossil fuels via carbon capture and storage. A suite of emerging IGCC technologies provide the promise of both high efficiency and reduced capital costs. Many of these operate at elevated temperature and hence a number of inorganic elements (i.e. elements other than C, H, O, N and S) may be present in the syngas at later stages of processing than is typical of conventional processing arrangements. Experimental results are presented for inorganic element distribution in slag and fly ash from seven entrained-flow slagging gasification plants. Data for the Siemens, Louisiana Gasification Technology Inc. (LGTI), Wabash River, ELCOGAS and Shell gasification systems were taken from literature. Data for the CanmetENERGY and Pratt and Whitney Rocketdyne (PWR) systems are presented for the first time. Mass balances and enrichment factors are calculated. All values are available in supplementary data tables. Challenges in data interpretation and general trends are highlighted. Mass balance closures for low volatility elements are within the range of 80-120% for the PWR, LGTI and Shell systems. Closures for the CanmetENERGY, Wabash River and ELCOGAS systems are further from 100%. Accumulation, unaccounted streams, measurement inaccuracy and sampling imperfections can cause poor mass balance closures. Comparison of enrichment factors for slag and fly ash demonstrate that many elements have similar fates in gasification systems as they do in combustion systems, although several elements are less volatile in gasification systems. Partitioning can vary for a given element when comparing different gasification systems and different operating conditions. The assessments of several elements which are of environmental or technological concern are provided as examples.