WHEC 16 / 13-16 June 2006 – Lyon France 1/7 Performance evaluation of integrated fuel processor for residential PEMFCs application Yu Taek Seo a , Dong Joo Seo a , Young-Seog Seo a , Hyun-Seog Roh a , Jin Hyeok Jeong b , Wang Lai Yoon a∗ a Hydrogen System Research Center, New Energy Research Department, Korea Institute of Energy Research, 71-2, Jang-dong, Yuseong-gu, Daejeon, 305-343 Korea b Chemical Engineering Department, Kyungpook National University , Korea ABSTRACT: KIER has been developing the natural gas fuel processor to produce hydrogen rich gas for residential PEMFCs system. To realize a compact and high efficiency, the unit processes of steam reforming, water gas shift, and preferential oxidation are chemically and physically integrated in a package. Current fuel processor designed for 1kW class PEMFCs shows thermal efficiency of 78% as a HHV basis with methane conversion of 90% at rated load operation. CO concentration below 10ppm in the produced gas is achieved with preferential oxidation unit using Pt and Ru based catalyst under the condition of [O 2 ]/[CO]=2.0. The partial load operation have been carried out to test the performance of fuel processor from 40% to 80% load, showing stable methane conversion and CO concentration below 10ppm. The durability test for the daily start-stop and 8hr operation procedure is under investigation and shows no deterioration of its performance after 40 start-stop cycles. KEYWORDS : Natural gas, Fuel processor, Steam reforming, PEMFCs, Residential cogeneration Introduction The fuel cell based power generation system is considered to be well qualified for a residential cogeneration system, which is generally incorporating the polymer electrolyte membrane fuel cells (PEMFCs) stack with hydrogen generation system from fossil fuels or renewable energy sources. PEMFCs based system has been widely developed because of its high efficiency, compactness, and reduction of air pollutants emission [1]. While introducing fuel cell systems into the market, small scale hydrogen generation system from various hydrocarbon feed stocks is required due to limited existing hydrogen infrastructures [2]. Many types of fuel processing system are being developed to meet quality of produced reformed gas that is pure enough for supplying to PEMFCs [3-5]. There exist well developed natural gas infrastructures in Korea, in which natural gas pipeline connected to the most of families and provide the hot water for heating by gas-fired boilers. Accordingly natural gas fuel processor adopting steam reforming process should be suitable for the residential PEMFCs system that requires high hydrogen concentration in reformed gas. Although the autothermal reforming process need relatively short start up time, the produced reformed gas contains less than 50% of hydrogen due to high content of nitrogen for internal combustion. Steam reforming process shows hydrogen concentration of about 75% in dry gas basis [6]. In case of steam reforming process, external burner is used to transfer the endothermic heat of reforming reaction and could avoid the failure of catalytic combustion and difficulties in maintenance. Accordingly the Korea Institute of Energy Research (KIER) is decided to develop a compact, integrated fuel processing system to provide hydrogen rich gas that can supply to PEMFCs system. The main focus of the work is to integrate the unit processes of a natural gas steam reforming, water gas shift, preferential oxidation, steam generator and internal heat exchangers into a single modular unit. In this project, the prototypes of fuel processor delivering 1.0Nm 3 /hr hydrogen were developed and tested to investigate the steady state behaviour at rated load operation. In parallel with the system integration, the steam reforming and CO preferential oxidation (PrOx) catalysts has been developed to improve the system performance. Especially the PrOx process is important to avoid the poisoning of PEMFC anode catalyst and guarantee the durability of PEMFCs cogeneration system. The Pt-based catalysts have been studied for CO removal process because of its high activity, in which CO was reduced to 100ppm with the addition of excess air corresponding to [O 2 ]/[CO]=2 and further reduced below 10ppm with additive air corresponding to [O 2 ]/[CO]≥3, at which excess oxygen consumes hydrogen in reformed gas by oxidation and reduces the reforming efficiency [7]. Recently, it is reported that novel Ru catalyst has high CO removal performance in a single-stage PrOx reactor with additive air corresponding to [O 2 ]/[CO]=1.5 by ∗ Corresponding author. Phone: +82 42 860-3070, Fax: +82 42 860-3309. E-mail address: wlyoon@kier.re.kr (Wang Lai Yoon).