Catalytica system

This cycle, often referred to as the Shilov-cycle converts methane into methanol and chloromethane in homogeneous aqueous solution at mild temperatures of 100-120 °C (11). However, while Pt(II) (added to the reaction as PtCl ) serves as the catalyst, the system also requires Pt(IV) (in the form of PtCle-) as a stoichiometric oxidant. Clearly, this system impressively demonstrates functionalization of methane under mild homogeneous conditions, but is impractical due to the high cost of the stoichiometric oxidant used. A recent development by Catalytica Advanced Technology Inc., often referred to as the Catalytica system used platinum(II) complexes as catalysts to convert methane into methyl-bisulfate (12). The stoichiometric oxidant in this case is S03, dissolved in concentrated H2S04 solvent. This cycle is depicted in Scheme 3. 

Fig. 14 Energetics, AG(s, 453 K) for possible precipitation routes in the Catalytica system [78]...

Scheme 9 Proposed mechanism for the Catalytica system electrophilic-type mechanism for CH hydroxylation of CH4 catalyzed by the (bpym)PtCl2/H2S04...

A variation of the Pd/Cu Wacker-Hoechst process, termed OK Technology, has been proposed by Catalytica Associates (40—46). This process avoids the use of chlorides and uses a Pd/Cu catalyst system which incorporates a polyoxoanion and a nitrile ligand. 

Figure 10-28. Schematic of a full scale catalytic combustor. Courtesy GE Power Systems and Catalytica Combustion Systems Inc.

Caron, T., Lemons, S., Nickolas, S., Tuet, P., and Gilbert, G.W. Catalytica Energy Systems, Inc. (2005) Xonon ultra low-nox combustion applied to multi-combustor gas turbines. Report for PIER, California Energy Commission, November 2005. 

A similar conclusion, that the alternative pathways sometimes differ only slightly in the energy barrier, was reached in several more recent theoretical papers which investigated methane activation in ( N2 )PtCl2 systems relevant to the Catalytica process. It has been demonstrated experimentally that compared with (bipyrimidine)PtCl2,... 

Clapsaddle, C. and Van Osdell, D. (2000) Environmental Technology Verification Report (ETV) - NO, Control Technologies - Catalytica Combustion System, Inc. XONON Flameless Combustion System, EPA Cooperative Agreement CR826152-01-2. 

Recently, researchers at Catalytica proposed a new technology for ethylene oxidation (368). Typical compositions are aqueous ca. O.l mM Pd2+, 5-25 mM Cl , and ca. 0.30 M NavH(3+ -v)PVxMoi2 04o (preferably x = 2-3). The Pd2+ and chloride concentrations are only 1/100 those in the oridinary Wacker system. The solutions at pHO-l result in high reaction rates and stability of Pd2+, as shown in Fig. 65. The stability of Pd2+ is further improved by the presence of chloride ion in a concentration of about 0.01 M. In this system, the phosphomolybdate serves two functions in the Pd° reoxidation (l) It solubilizes high concentrations of Vs + in aqueous solution and (2) it accelerates the reoxidation of V4+ by dioxygen. Kinetics (the reaction is first-order in Pd2+ and in ethylene concentrations and zero-order in Vs + concentration) shows that the oxidation of ethylene to produce acetaldehyde is rate-determining. 

Xonon Cool Combustion A catalytic technology that combusts fuel flamelessly. Incorporated inside a gas turbine engine, it reduces the production of oxides of nitrogen to < 3 ppm by volume. Developed by Catalytica Energy Systems, CA. First demonstrated in 2002 in cooperation with Kawasaki Gas Turbines-Americas in Sonoma. The development was abandoned in 2006 because of unfavorable gas-turbine market conditions. 

At present, one catalytic combustion system has been implemented at a full scale the XONON Cool Combustion technology, developed by Catalytica Energy Systems 157,158). The system is operated as follows Fuel from a lean-mix prebumer and the main fuel stream together with compressed air pass through the catalyst module (palladium oxide catalyst deposited on corrugated metal foil) in which the gas reaches a temperature up to 1623 K. The UHC and CO are combusted to essentially full conversion, downstream of the catalyst in the homogenous combustion zone. The guaranteed emission levels are as follows NOj < 3 ppm. 

MTI and Catalytica are working together to develop compact fuel processors for use with PEMFCs and solid oxide fuel cells (SOFCs). This system is designed to reform gasoline and Naval Distillate for PEMFCs. 

Supporting systems studies are being conducted by Gilbert/ Commonwealth, Inc., Gorham International, Inc., Science Applications, Inc., and Catalytica Associates, Inc. 

R. L. Garten, R. A. Dalla Betta and J. C. Schlatter, Catalytica Combustion Systems, 430 Ferguson Drive, Bldg 3, Mountain View, CA 94043-5272/USA... 

Figure 3. Schematic temperature profiles for Catalytica catalytic combustion system in which the wall temperature is limited and complete combustion occurs after the catalyst.

R. A. Dalla Betta Catalytica Combustion Systems 430 Ferguson Drive Bldg 3... 

Other companies like Hitachi in Japan, Catalytica Associates in the United States, and Haldor Topsoe in Denmark have proposed other systems engineering approaches similar to these two cases described above. The principle everywhere is the same bring in a catalyst for the specific and local limited requirement in a small part of the combustor, use different catalysts for different zones in the combustor, and protect these catalysts from extreme conditions for which they are not designed. 

Main Subcontractors Catalytica Energy Systems and NexTech Materials, Ltd. (NexTech) Objectives... 

Produced required amount of Catalytica Energy System s autothermal reformer (ATR) catalyst. Produced required amount of NexTech platinum (Pt)/ceria medium-temperature-shift (MTS) catalyst. Obtained Eos Alamos National Eaboratory preferential oxidation (PROX) reactor. 

The catalyst scheme is summarized in Table 3. The required amount of Catalytica Energy Systems ATR catalyst was produced and installed in the reactor. The required amount of NexTech shift catalyst was produced and installed in the first stage shift reactor. The NexTech shift catalyst is a medium-temperature shift catalyst that remains active in the oxidized or reduced state and is less sensitive to condensed moisture [2]. All catalysts are currently in pellet form however, noble metal wash coating on monolith substrates is existing technology. Therefore, once the catalyst and system performance are verified, it will be straightforward to convert these catalysts to monoliths. The reactors... 

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