Fuel medium-temperature

Hot water boilers are potentially more susceptible to gas-side corrosion than steam boilers due to the lower temperatures and pressures encountered on low- and medium-temperature hot water boilers. With low-temperature hot water especially, the water-return temperature may drop below the water dewpoint of 50°C, causing vapor in the products of combustion to condense. This, in turn, leads to corrosion if it persists for long periods. The remedy is to ensure that adequate mixing of the return water maintains the water in the shell above 65°C at all times. Also, if medium or heavy fuel oil is to be used for low- or medium-temperature applications it is desirable to keep the heat transfer surfaces above 130°C, this being the approximate acid dewpoint temperature of the combustion gases. It may be seen, therefore, how important it is to match the unit or range of unit sizes to the expected load. 

Medium-temperature phosphoric acid fuel cells (PAFCs). The electrolyte is 85 to 95% phosphoric acid the working temperatures are 180 to 200°C. Such systems were used to build numerous autonomous power plants with an output of up to about 250 kW, and even some with an output of up to 4 MW, in the United States, Japan, and other countries. 

MTH [Mittel-Temperatur-Hydrierung German, meaning medium-temperature hydrogenation] A version of the TTH process, using different processing conditions, by which a larger proportion of transport fuels could be produced. 

Bormet, B., Jones, D. J., Roziere, J., Tchicaya, L., Alberti, G., Casciola, M., Massinelli, L., Bauer, B., Peraio, A. and Rumunni, E. 2000. Hybrid organic-inorganic membranes for a medium-temperature fuel cell. Journal of New Materials for Electrochemical Systems 3 87-92. 

Alberti, G. and Casciola, M. 2003. Composite membranes for medium-temperature PEM fuel cells. Annual Review of Materials Research 33 129-154. 

Coal Char Coal char is, generically, the nonagglomerated, non-fusible residue from the thermal treatment of coal however, it is more specifically the solid residue from low- or medium-temperature carbonization processes. Char is used as a fuel or a carbon source. Chars have compositions intermediate between those of coal and coke the volatile matter, sulfur content, and heating values of the chars are lower, and the ash content is higher, than those of the original coal. 

Phosphoric acid fuel cell (PAFC) working at 180-200 °C vfith a porous matrix of PTFE-bonded silicon carbide impregnated with phosphoric acid as electrolyte, conducting by the H cation. This medium-temperature fuel cell is now commercialized by ONSI (USA), mainly for stationary applications. 

Substituting the HT and LT shift with an isothermal Medium Temperature shift with a typical exit temperature of 260 °C would produce results similar to those provided by the combination of HTS and LTS. It is obvious that only a relatively expensive feed and a cheaper fuel would justify the additional investment needed to supplement the HT shift with a LT shift or install an isothermal MT shift in place of both of them225. 

G. Alberti, M. Casciola, L. Massinelli, and B. Bauer. Polymeric proton conducting membranes for medium temperature fuel cells (110-160 degrees C). Journal of Membrane Science 185, 73-81 2001. 

Development of supported Pt electrocatalysts came as a result of intensive research on fundamental and applied aspects of electrocatalysis [especially for kinetically difficult oxygen reduction reaction (ORR)] fueled by attempts at commercialization of medium-temperature phosphoric acid fuel cells (PAFCs) in the late 1960s and early 1970s. Dispersion of metal crystallites in a conductive carbon support resulted in significant improvements in all three polarization zones (activation, ohmic, and... 

Relatively less attention has been given to the desulfurization of steam-containing gas mixtures with low H2S at medium temperature suitable for desulfurization of reformate from the reforming, where the temperature of the fuel gas at the outlet of the steam reforming is about 700 °C and at the inlet of high-temperature water-gas shift (HTWGA) is about 400 °C. 

Alberti, G. Casciola, M. Palombari, R. Inor-gano-organic proton conducting membranes for fuel cells and sensors at medium temperatures. J. Membr. Sci. 2000, 172, 233. 

High-Performance Electrodes for Medium-Temperature Solid Oxide Fuel Cells... 

Further progress is expected from new developments and combinations of processes. Thus, it would be possible to make the disposal of the gaseous (and highly pure) waste gas streams (residual propane content of the propylene feed) cost-effective and a source of electric power by connection to novel, compact, membrane fuel cells. Potential synergisms would also occur in the operating temperature of the cells (medium-temperature cells at 120 °C using the residual exothermic heat of reaction from the oxo reaction), the membrane costs by means of combined developments (e.g., for membrane separations of the catalysts [22]), and also in the development of the zero-emission automobile by the automotive industry. The combination of hydroformylation with fuel cells would further reduce the E-factor - thus approaching a zero-emission chemistry. ... 

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