Single-chamber reactor

The experimental setup used for the first bipolar or wireless NEMCA study is shown in Figure 12.6.8 An YSZ disc with two terminal Au electrodes and one Pt catalyst film deposited on one side and a reference Au electrode on the other side is placed in a single-chamber reactor. Ethylene oxidation on the Pt catalyst film was chosen as a model reaction.8... 

Figure B.l. (Top) Typical reactor designs used in electrochemical promotion studies singlechamber design (left) and fuel cell type design (right). (Bottom) Typical apparatus for electrochemical promotion studies using a three-pellet single chamber reactor.

Two types of continuous flow solid oxide cell reactors are typically used in electrochemical promotion experiments. The single chamber reactor depicted in Fig. B.l is made of a quartz tube closed at one end. The open end of the tube is mounted on a stainless steel cap, which has provisions for the introduction of reactants and removal of products as well as for the insertion of a thermocouple and connecting wires to the electrodes of the cell. A solid electrolyte disk, with three porous electrodes deposited on it, is appropriately clamped inside the reactor. Au wires are normally used to connect the catalyst-working electrode as well as the two Au auxiliary electrodes with the external circuit. These wires are mechanically pressed onto the corresponding electrodes, using an appropriate ceramic holder. A thermocouple, inserted in a closed-end quartz tube is used to measure the temperature of the solid electrolyte pellet. 

The single cells consist of a dense solid electrolyte membrane and two porous electrodes. In most cases, at least one of the electrodes is exposed to an oxygen-containing gas (often, ambient air), while the other electrode is exposed to an inert gas, a liquid metal, a partial vacuum, or a reacting mixture (hydrogen, water vapor, hydrocarbons, CO, CO2, etc.). The single-chamber reactor (SCR) has been also proposed either as a membrane reactor or as a fuel cell. In this case, the solid-electrolyte disk, with two different electrodes that are coated either on opposite sides or on the same side of the pellet, is suspended in a flow of the reacting mixture (see Section 12.6.3). 

In PCMRs, the reactors can be classified by the design and the atmosphere in which they are operated. A single-chamber reactor performs under a single atmosphere, while a double-chamber reactor consists of two separated chambers with different atmospheres. Generally, both reactors contain the same components, including a membrane electrolyte with two electrodes and an external power source. The external power source is connected between the anode and the cathode and takes control the direction of the reaction. 

Figure 18.4 illustrates a schematic of a single-chamber reactor. All reactant gases are mixed and directly fed into the same chamber, in which the membrane cell is suspended. 

In single-chamber reactor, the A value would be possible to exceed the unity. This means that there is additional hydrogen from the gas phase that accompanies the electrochemical hydrogen in the same reaction. This phenomenon is called non-Faradaic electrochemical modification of catalytic activity (NEMCA). The concept of the NEMCA effect is different from Faradaic effect. In NEMCA, an electrode will serve as a catalyst for two simultaneous processes, chemical processes and electrochemical processes. 

Figure 18.4 Schematic diagram of a single-chamber reactor.

Rozendal et al. 2007). They referred to this as a single chamber reactor, although a second chamber is still needed for gas collection. Overall H2 recovery was low with either a OEM or an anion exchange membrane (rH2 = 23%). 

In the single-chamber type reactor (Fig. 4.1b) all three electrodes (catalyst-working (W), counter (C) and reference (R)), electrode are all in the same chamber and are all exposed to the reactants and products.1 3 In this case the counter and reference electrodes must be made from a catalytically inert (e.g. Au) material for otherwise the catalytic rate on them will obscure the measured (via gas-chromatography or mass-spectrometry, Fig. 4.2) rate on the catalyst-working electrode. 

Figure 4.1. Electrode configuration for NEMCA studies using (a) the fuel cell type reactor and (b) the single-chamber type reactor.

Hot reactor walls are sometimes used as a means to increase the density of the films that are deposited on the walls. This reduces the amount of adsorbed contaminants on the walls, and leads to lower outgassing rates. A hot wall is particularly of interest for single-chamber systems without a load-lock chamber. Material quality is similar to the quality obtained with a cold reactor wall [145],... 

Figure 11.19 384-parallel single-bead reactor with independent microreaction chambers and integrated flow restrictors. Typical bead diameter 1 mm. 

Figure 13 Illustration of a single microplasma reactor and its integration in a multireactor. Numbered features are (1) plasma source, (2) glass structure, (3) reaction chamber, (4) inlet and outlet of the reactor, (5) gas flow, (6) 4 x 4 array in a multireactor, and (7) contact pads for RF power (Sichler et at, 2004 reproduced with permission).

Second, the committee believes ERH testing conducted with a batch, single-chamber flight reactor can adequately simulate the kinetics of energetics hydrolysis in the multi-... 

Savoie, S., Napporn, T.W., Morel, B., Meunier, M., and Roberge, R. (2011) Catalytic activity of Ni-YSZ anodes in a single-chamber solid oxide fuel cell reactor. J. Power Sources, 196 (8), 3713-3721. 

There are two separate mechanisms for treating water by electroflocculation batch and continuous flow. Both systems involve a reaction chamber into which is placed a set of electrodes. In a batch system, a single chamber holds all the electrodes and water, as illustrated in Fig. 1. The water is pumped into the reactor, the current for the electrochemical reactions is passed, and the pollutants float to the surface. In this situation, they are best removed by raising the water level, which forces the floe out the top chute. The water rests in the chamber for a predetermined time before it is pumped out. With batch processes requiring time for the water to be pumped in and out, there is a practical volume limit of about 10 kL per batch, beyond which pump in/out times may be too long to be practical. 

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