Active fault diagnosis for uncertain systems using optimal test designs and detection through classification.

Fault detection and isolation (FDI) is becoming increasingly difficult due to the complexity and uncertainty of modern systems. For industrial systems with explicit models available, model-based active FDI tests can improve the capability for fault diagnosis. These tests should be determined and evaluated prior to implementation to minimize on-site computational costs. In this paper, a methodology is presented for the design optimization and assessment of tests for active fault diagnosis. The objective is to maximize the information from system outputs with respect to faults while minimizing the correlation between faults and uncertainty. After a test is designed, it is deployed with a k-nearest neighbor algorithm combined with principal component analysis.Two case studies are used to verify the proposed methodology, a three-tank system and a diesel engine.

Investigation of in situ and ex situ catalytic pyrolysis of miscanthus × giganteus using a PyGC-MS microsystem and comparison with a bench-scale spouted-bed reactor.

The objective of the present work is to explore the particularities of a micro-scale experimental apparatus with regards to the study of catalytic fast pyrolysis (CFP) of biomass. In situ and ex situ CFP of miscanthus × giganteus were performed with ZSM-5 catalyst. Higher permanent gas yields and higher selectivity to aromatics in the bio-oil were observed from ex situ CFP, but higher bio-oil yields were recorded during in situ CFP. Solid yields were comparable across both configurations. The results from in situ and ex situ PyGC were also compared with the product yields and selectivities obtained using a bench-scale, spouted-bed reactor. The bio-oil composition and overall product distribution for the PyGC ex situ configuration more closely resembled that of the spouted-bed reactor. The coke/char from in situ CFP in the PyGC was very similar in nature to that obtained from the spouted-bed reactor.

Catalytic pyrolysis of miscanthus × giganteus in a spouted bed reactor.

A conical spouted bed reactor was designed and tested for fast catalytic pyrolysis of miscanthus × giganteus over Zeolite Socony Mobil-5 (ZSM-5) catalyst, in the temperature range of 400-600 °C and catalyst to biomass ratios 1:1-5:1. The effect of operating conditions on the lumped product distribution, bio-oil selectivity and gas composition was investigated. In particular, it was shown that higher temperature favors the production of gas and bio-oil aromatics and results in lower solid and liquid yields. Higher catalyst to biomass ratios increased the gas yield, at the expense of liquid and solid products, while enhancing aromatic selectivity. The separate catalytic effects of ZSM-5 catalyst and its Al2O3 support were studied. The support contributes to increased coke/char formation, due to the uncontrolled spatial distribution and activity of its alumina sites. The presence of ZSM-5 zeolite in the catalyst enhanced the production of aromatics due to its proper pore size distribution and activity.