Fuel manifolds

Two types (type A and B) of micro SOFC stacks were prepared as shown in Fig, 2 using those micro tubular SOFC bundles. The type A was constructed using four micro bundles with. 8 mm tubes, vertically connected in series after applying sealing layer and interconnects to each bundle. Fuel and air were applied using ceramic manifolds as shown in Fig. 2 (a). The type B consists of three bundles, sealing layers and interconnects, and fuel manifolds. The size of the stack A without fuel manifold is I x I x 0.8 cm ( 0.8 cm ) and the size of the stack B without fuel manifold is 1 x 3 cm with tlie thickness of 3.3 mm ( 1 cm ). 

Fabrication and characterization of tubular SOFC stacks designed for low temperature operation were shown. Two types of stacks were proposed and demonstrated using the micro tubular SOFC bundles the type A was a vertically assembled stack, four-story cube-type stack with the volume of about 0.8 cm The performance of the type A stack was shown to be 3.6 V OCV and 2 W maximum output power under 500 °C operating temperature. Another type of the stack was also fabricated, which consists of three bundles and fuel manifolds, where the air was applied only by natural convection. Open circuit voltages of the type B stack were shown to be 2.85 and 2.73 V at 450 and 500 C operating temperatures, with the maximum power outputs of 0.91 and 1.54 W. Overall, both types of stacks showed reasonably sufficient performance for application use. 

Small burners without preheated air are generally controlled by cross-connected air/fiiel ratio regulators (one for each burner). This arrangement is ideal because it saves the operator from constantly having to adjust the ratio—until the paint is worn off the hand dial— because of changing maldistributions of flows in either air or fuel manifold. 

Air and Fuel Manifolds. It is difficult to correct bad manifold designs therefore, it is important to be generous in initial air and fuel manifold sizing, and get it right the first time. (See fig. 6.10.) Designers should think of manifolds as plenums that should be sized for low velocities. A nonuniform air or fuel distribution often changes its maldistribution as burners are turned up and down. An easy, safe design has the manifold cross-sectional area equal to the sum of the cross-sectional areas of all of its offtake pipes. (See references 54 and 60.)... 

Combustor housing assembly Gas fuel manifold Bleed air valve Ignitor... 

At fuel manifold inlets, gaseous species concentrations are specified as equilibrium compositions of the town gas reformate at 650°C. Steam-to-carbon ratio is kept as 3.06 for this particular steady-state analysis. Both fuel and air gas manifold inlet conditions are summarized in Table 9.5. Mixed convective and radiative heat transfer boundary conditions are applied to the side surfaces of the stack to accurately model the heat exchange with the balance of plant components. Top and bottom surfaces, on the other hand, are assigned with... 

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