Reviews on Fuel Cell Technology for Valuable Chemicals and Energy Co-Generation

This paper provides a review of co-generation process in fuel cell type reactor to produce valuable chemical compounds along with electricity. The chemicals and energy co-generation processes have been shown to be a promising alternative to conventional reactors and conventional fuel cells with pure water as a byproduct. This paper reviews researches on chemicals and energy co-generation technologies of three types of promising fuel cell i.e. solid oxide fuel cell (SOFC), alkaline fuel cell (AFC), and proton exchange membrane fuel cell (PEMFC). In addition, the research studies on applications of SOFCs, AFCs, and PEMFCs with chemical production (i.e. nitric oxide, formaldehyde, sulfur oxide, C2 hydrocarbons, alcohols, syngas and hydrogen peroxide) were also given. Although, it appears that chemicals and energy co-generation processes have potential to succeed in commercial applications, the development of cheaper catalyst materials with longer stability ,and understanding in thermodynamic are still challenging to improve the overall system performance and enable to use in commercial market

Removal of H2S from Biogas by Iron (Fe3+) Doped MgO on Ceramic Honeycomb Catalyst using Double Packed Columns System

Hydrogen sulfide is a toxic and corrosive in nature, gas should be safely removed from the biogas streams before subjecting into the fuel cell. Fe3+ doped magnesium oxide was synthesized using sol-gel technique and dip coating process of Fe3+ doped MgO on foam ceramic honeycomb. XRD and SEM indicate that Fe3+ in Fe3+ doped MgO on foam ceramic honeycomb catalyst is finely dispersed in the MgO support. Performance of the synthesized Fe3+ doped magnesium oxide on the honeycomb catalyst was examined for hydrogen sulfide (H2S) oxidation by double packed column scrubbers. The absorption column was used for H2S scrubbing from biogas by deionized water absorption and catalytic column was used as catalyst bed for degradation of absorbed H2S in scrubbing water. In the catalytic column, counter current flow of the scrubbing water and air through the catalyst pack was performed for H2S oxidation accompany with catalyst regeneration. System capacity for H2S removal from gas stream showed 98% constant along 3 hr testing time at room temperature

Activity-Based Costing Analysis for Train Station's Service

Laem Chabang train station is subsidiary to container transportation office of The State Railway of Thailand. Its main objective is to provide services to container and oil trains of about 900 - 1000 container trains and 120 oil trains (inbound-outbound) each month. Its operation is divided into two main part: Laem Chabang station and Laem Chabang Port station operates 24 hours a day. This report does research on services of both stations. The services can be categorized into two types: container train service and oil train services which are different in their processes. This report analyze activity-based costing especially in the Laem Chabang train station's direct expense which is not include other organizations' expenses such as mechanical department, civil department or signaling department. Formerly, The State Railway of Thailand had not been calculating this kind of cost, the workgroup thus attempts to make activity-based costing of Laem Chabang train station to improve its service procedure and reduce its future cost. From calculation cost of service of Laem Chabang train station by applying activity-based costing, the cost of activity for each type of train is revealed. The cost of service for oil train is 1,575.85 baht per train, for container train entering zone B port is 809.61 bath per train and for container train entering zone C port is 811.76 bath per train. It is found that cost of service for oil train is the highest due to its lower client which is about one-eighth of container train; that is conforms to the law of demand and supply. In order to reduce cost, it can be considered to operate more oil trains or to decrease the number of labour related to oil train because most of the cost comes from labour salary (about 83%). Thus, optimization of labour can clearly lower overall cost

Simultaneous removal of CO2 and H2S using MEA solution in a packed column absorber for biogas upgrading

Biogas production and utilization is an emerging alternative energy technology that has gained importance since the price of oil and gas has increased steadily over the last two decades. Biogas primarily consists of methane (CH4) and carbon dioxide (CO2) with smaller amounts of hydrogen sulfide (H2S) and ammonia (NH3). For many applications the quality of biogas has to be improved. The main parameters that may require removal in upgrading systems are CO2 and H2S. This work presents the study of simultaneous absorption of CO2 and H2S by Monoethanolamine (MEA) solution in a packed column. Simulated biogas containing 40% CO2 and 60% N2 and biogas generated from an anaerobic digestion plant were used as feed gas streams. The effects of gas flow rate, L/G ratio and absorbent concentration were investigated. The performance of the system was found to vary with process parameters. Increasing L/G ratio and MEA concentration causes the system efficiency to increase whereas increasing gas flow rate results in lower efficiency. An operating condition of L/G ratio of 83.3 ml/L, gas flow rate of 3 L/min and MEA concentration of 3 mol/L was found to remove more than 99.5% of CO2 and H2S from biogas. The volumetric overall mass-transfer coefficient (KGav) for CO2 removal initially increases with increasing gas flow rate up to a certain value beyond which the coefficient becomes essentially constant. The KGav also increases with increasing L/G ratio throughout the range tested in this study

Two-Dimensional Modeling of the Oxidative Coupling of Methane in a Fixed Bed Reactor: A Comparison among Different Catalysts

A proposed two-dimensional model of the oxidative coupling of methane (OCM) to C2 hydrocarbons (e.g., C2H4 and C2H6) in a fixed bed reactor operated under isothermal and non-isothermal conditions is described which can provide more accurate predictions of experimental data than the simplified one-dimensional model. The model includes a set of partial differential equations of the continuity, mass transfer and energy balance equations. The performance of the OCM using different catalysts was assessed in terms of CH4 conversion, C2 selectivity and C2 yield with respect to key operating parameters, such as feed temperature (973-1173 K), CH4/O2 ratio (3.4–7.5) and gas hour space velocity (GHSV) (18000-30000 h-1). The simulation results indicated that the Na-W-Mn/SiO2 catalyst exhibits the best performance among all of the catalysts. The C2 yield were 20.16% and 20.00% for non-isothermal and isothermal modes respectively which the OCM reactor is operated at a CH4/O2 ratio of 3.4, a feed temperature of 1073 K and a GHSV of 9720 h-1. An increase in the operating temperature increases the CH4 conversion but decreases the C2 selectivity. However, the effects of the CH4/O2 ratio and the GHSV exhibit an opposite trend to that of the operating temperature.A proposed two-dimensional model of the oxidative coupling of methane (OCM) to C2 hydrocarbons (e.g., C2H4 and C2H6) in a fixed bed reactor operated under isothermal and non-isothermal conditions is described which can provide more accurate predictions of experimental data than the simplified one-dimensional model. The model includes a set of partial differential equations of the continuity, mass transfer and energy balance equations. The performance of the OCM using different catalysts was assessed in terms of CH4 conversion, C2 selectivity and C2 yield with respect to key operating parameters, such as feed temperature (973 - 1173 K), CH4/O2 ratio (3.4 – 7.5) and gas hour space velocity (GHSV) (18000 - 30000 h-1). The simulation results indicated that the Na-W-Mn/SiO2 catalyst exhibits the best performance among all of the catalysts. The C2 yield were 20.16% and 20.00% for non-isothermal and isothermal modes respectively which the OCM reactor is operated at a CH4/O2 ratio of 3.4, a feed temperature of 1073 K and a GHSV of 9720 h-1. An increase in the operating temperature increases the CH4 conversion but decreases the C2 selectivity. However, the effects of the CH4/O2 ratio and the GHSV exhibit an opposite trend to that of the operating temperature

Synthesis of Na2WO4-Mn Supported YSZ as a Potential Anode Catalyst for Oxidative Coupling of Methane in SOFC Reactor

The oxidative coupling of methane (OCM) over a 5%Na2WO4-2%Mn on YSZ, has been investigated in a fixed bed reactor (FBR) and a solid oxide fuel cell reactor (SOFC). A 60% C2 selectivity and a 26% CH4 conversion have been obtained in a FBR at 800oC and CH4/O2 of 4 : 1. Importantly, an addition of Na2WO4-Mn to YSZ support can significantly enhance the performance of the catalyst especially C2 hydrocarbons selectivity and CH4 conversion. A maximum power density of 7.8 mW cm−2 was achieved at 800°C with CH4 in the SOFC reactor having a 50 μm thick YSZ electrolyte. The CH4 conversion and C2 selectivity at 800°C were 1.1% and 85.2%, respectively

Oxidative Coupling of Methane over YSZ Support Catalysts for Application in C2 Hydrocarbon Production

This paper studies the development of Mn-Na2WO4 catalysts on YSZ support for oxidative coupling of methane reaction. It can be divided into two parts; (1) study in fixed bed reactor (FBR), and (2) study in solid oxide fuel cell reactor (SOFC). In part I, the experiments were performed using co-feeds of methane, oxygen and nitrogen inert gas at a ratio of 4:1:5 for different temperatures (973 - 1173 K). Mn-Na2WO4 catalyst on YSZ support was doped with sulfur, phosphorous, and cerium in order to improve its catalytic reactivity. The results indicated that sulfur and phosphorous showed the good improvement for Mn-Na2WO4 catalyst on YSZ support. At 1073 K, S-Mn-Na2WO4/YSZ provided C2 selectivity of 60.3% and methane conversion of 31.1%, while P-Mn- Na2WO4/YSZ offered C2 selectivity of 59.8% and methane conversion of 34.1%. P-Mn-Na2WO4/YSZ catalyst was selected as anode catalysts for further study in the SOFC reactor. The experiments were carried out using La0.8Sr0.2MnO3 (LSM) as the cathode catalyst, 8 mol% yttria-stabilized zirconia (YSZ) as the electrolyte. P-Mn-Na2WO4/YSZ exhibited the best performance, providing C2H4 selectivity of 89.0%, methane conversion of 10.5% and maximum power density of 7.2 W/m2 at 1123 K. In addition, the stability of the P-Mn-Na2WO4/YSZ catalyst was tested at 1123 K. Good stability of the reaction system could be observed at least for 29 hours

Two-Dimensional Mathematical Modeling of the Oxidative Coupling of Methane in a Membrane Reactor

The oxidative coupling of methane (OCM) in a dense BSCFO membrane reactor (MR) was theoretically studied using a two-dimensional reactor model. The simulation results indicated that increasing the operating temperature results in increased CH4 conversion and decreased C2 selectivity. An increase in the methane feed flow rate lowers the CH4 conversion but increases the C2 selectivity; however, the effect of the air flow rate on the OCM membrane reactor exhibits an opposite trend. The optimum configuration of the dense BSCFO-MR to provide the best performance was 0.018 m in diameter and 0.2 m in length at a GHSV of 38904.54 h-1 and temperature of 1073 K. Under these optimal conditions, the CH4 conversion is 43.713%, the C2 selectivity is 61.352% and the C2 yield is 26.82%

Reviews on Solid Oxide Fuel Cell Technology

oai:www.engj.org:article/25Solid Oxide Fuel Cell (SOFC) is one type of high temperature fuel cell that appears to be one of the most promising technology to provide the efficient and clean energy production for wide range of applications (from small units to large scale power plants). This paper reviews the current status and related researches on SOFC technologies. In details, the research trend for the development of SOFC components(i.e. anode, electrolyte, cathode, and interconnect) are presented. Later, the current important designs of SOFC (i.e. Seal-less Tubular Design, Segmented Cell in Series Design, Monolithic Design and Flat Plate Design) are exampled. In addition, the possible operations of SOFC (i.e. external reforming, indirect internal reforming, and direct internal reforming) are discussed. Lastly, the research studies on applications of SOFCs with co-generation (i.e. SOFC with Combined Heat and Power (SOFC-CHP), SOFC with Gas Turbine (SOFC-GT)) and SOFC with chemical production) are given

Performance Assessment of SOFC Systems Integrated with Bio-Ethanol Production and Purification Processes

The overall electrical efficiencies of the integrated systems of solid oxide fuel cell (SOFC) and bio-ethanol production with purification processes at different heat integration levels were investigated. The simulation studies were based on the condition with zero net energy. It was found that the most suitable operating voltage is between 0.7 and 0.85 V and the operating temperature is in the range from 973 to 1173 K. For the effect of percent ethanol recovery, the optimum percent ethanol recovery is at 95%. The most efficient case is the system with full heat integration between SOFC and bio-ethanol production and purification processes with biogas reformed for producing extra hydrogen feed for SOFC which has the overall electrical efficiency of 36.17%. However more equipment such as reformer and heat exchangers are required and this leads to increased investment cost