Solid-state combustion

Combustion Synthesis. Besides solid-state reactions requiring heating even for several days at high temperatures to be completed, fast reactions are also known which give their products in minutes or seconds. Several nearly equivalent names are used for these reactions such as solid-state combustion, combustion synthesis, self-propagating (self-sustained) high-temperature synthesis. Solid state direct combinations and solid-state metathesis have been described. 

FIGURE 15.15 Combustion efficiency (%) of various PC/ABS materials calculated using the THE/ML measured in the cone calorimeter, and the heat release per ML for the complete combustion of the volatiles monitored in the PCFC. Systems that do not show flame inhibition show combustion efficiencies of around 1, according to the well-ventilated fire scenario of the cone calorimeter. Systems, in which adding aryl phosphates result in flame inhibition, show combustion efficiencies of around 0.8. When the release of phosphorus is reduced by competing reactions in the solid state, combustion efficiencies of between 0.8 and 1 are observed. 

Anselmi-Tamburini, U., and Munir, Z. A., The propagation of a solid-state combustion wave in Ni-Al foils. J. Appl. Phys., 66,5039 (1989). 

NANOCRISTALLINE POWDERS SYSTEM ZrOi - SC2O3 FOR SOLID-STATE COMBUSTION CELLS... 

Aguas, M.D., Affleck, L., Parkin, I.P., Kuznetsov, M.V., Steer, W.A., Pankhurst, QA Femfindez-Barqufn, L Roberts, MA Boamfti, M.I., and Perenboom, JA.A.J. (2000) The effect of large magnetic fields on solid state combustion reactions novel microstructure, lattice contraction and reduced coercivity in barium hexaferrite. /, Mater. Chem, 10, 235-237. 

At about the same time, Ric Kaner et al. reported, for the first time, about the formation of multi-walled carbon nanotubes by the reaction of PTFE with lithium acetylide, Li-C=C-Li, in a solid-state combustion reaction (R.B. Kaner, personal communication) [8, 9]. 

In this chapter, we will focus on the synthesis and characterization of lanthamun strontimn manganites for application as cathodes in SOFC. Firstly we will review some characteristics of perovskites which are important to imderstand their performance in SOFC crystal structure, electrical conductivity, thermal stability and chemical reactivity. Then, the review will be directed to the synthesis methods of LSM powders, focusing on those used by our group solid-state, combustion, and citrate methods. Finally, extensive results and discussions will be presented on the characterization of LSM synthesized by these three different methods. 

LSM powders were successfully synthesized by three different preparation methods solid-state, combustion, and citrate synthesis, with characterization of their structural, morphological and electrical properties. 

Diffusion in solids does not ensure the experimentally observed velocity of combustion wave propagation in the systems which are traditionally considered as gasless and burned in the mode of solid flames (gasless solid-state combustion). The phenomenology of indirect interactions, the thermochemistp and dynamics of the gas-phase carriers formation, as well as their participation in the reactants transport are studied in the systems Mo-B and Ta-C. The distributions of the main species in the gas phase of the combustion wave are measured in situ with the use of a dynamic mass-spectrometry (DMS) technique which allows for high temporal and spatial resolution. The detailed chemical pathways of the processes were established. It was shown that the actual mechanism of combustion in the systems under study is neither solid state nor gasless and the reactions are fiilly accomplished in a narrow front. 

If, for the set of reactants and intermediate products (substances and phases), > Tf, and the partial pressure of reactants and products (P/) at Tf is much lower than the ambient pressure Pq), it is believed that solid-state combustion takes place and the so called "solid flame" is observed. Following common logic, one can suppose that combustion synthesis in the system solid solid has to proceed in the mode of reactive diffusion. However, the td value (at the diffusion coefficient in solids Dg 10 cmVs and the distance equal to the particle size of the metal powder r -10 pm) can be estimated as Ti) = -10 s. This value considerably exceeds the maximum residence time for par-... 

The study of the detailed chemical mechanism of solid-state combustion, also called gasless combustion (7 7) and solid flames 18 was the goal of present work. The combustion processes of the systems Mo-B and Ta-C are considered to be classic examples of this phenomenon and were chosen as the subjects of this study. 

The study of the detailed chemical mechanisms of combustion synthesis in the systems considered as classic examples of gasless solid-state combustion or the so called "solid flame" shows that, in fact, these processes are neither gasless, nor solid-state. 

With internaJ-combustion engines, automatic transmissions are frequently used these are easily justified when vehicles must make many moves during the day. Smooth as is the control afforded by automatic transmissions, it is neveriheless inferior to that provided by electric trucks, especially those with solid-state controls. Gasoline and diesel power are also used, but mostly for outdoor equipment and very-heavy-duty units. 

Maintenance on gas trucks is also higher than with electric vehicles. About 5 percent annually of the initial cost applies to internal-combustion equipment, and about 2 percent annually to electric. A special feature on electric trucks with solid-state controls is the use of modules or circuit boards, which can be replaced as units and rebuilt at the factoiy. Typical maintenance costs for trucks operating five 8-h shifts per week are in the order of 3.15 per hour for gas vehicles and 1.78 per hour for electric ones. Under these conditions, energy costs are typically 9.3 cents per hour for gas trucks and 5.1 cents per hour for the electric units. 

A solid propellant is a mechanical (heterogeneous) or a chemical (homogeneous, or colloidal) mixture of solid-state fuel and oxidizer-rich chemicals. Specially-formed charges of solid propellant (grains) arc placed in the combustion chamber of the solid rocket motor (SRM) at a production facility. Once assembled, the engine does not require additional maintenance, making it simple, reliable and easy to use. 

R.S. Brown et al, AdvanChemEng 7, 1—69 (1968) CA 72, 11368 (1970) The topics reviewed include types of solid proplnts, sohd-proplnt rocket motors, ignition, steady-state combustion, and combustion instability and termination... 

The combustion of oil, gas, PF, wood dust, and many other types of fuels in a furnace requires specially designed burners together with an ignitor. Burners use solid state, automatic management systems to proportion and mix fuel, primary air, and secondary air prepare the mixture for combustion and monitor the firing sequence. 

B3. Barrere, M., Williams, F. A., Analytical and Experimental Studies of the Steady State Combustion Mechanism of Solid Propellants, 1965. 

The role of plastics in municipal solid waste combustion is discussed, and in particular, their fuel characteristics. Details are given of a state-of-art municipal solid waste combustor and the effects of plastics on the different combustion stages. In addition, the contribution of plastics to the total output spread over the various emission paths of solids, liquids and gases, is also assessed. 

It oxidised violently when it was heated with potassium nitrate. When it was submitted to a pressure of 70 bar and sodium nitrate was present, it detonated violently. With ammonium nitrate in the molten state it combusts, whereas in the solid state it detonates when exposed to impact. 

With carbon dioxide in the solid state the mixture detonates on impact. Therefore, with graphite, carbon dioxide cannot be used as an extinguishing agent for potassium fires. The slow reaction of potassium with gaseous carbon dioxide at ambient temperature gave rise to an accident. Potassium was stored in an aluminium container in a laboratory in contact with carbon dioxide the formation of potassium carbonate caused the corrosion of the container, which caused potassium to combust on contact with air. 

Boron trifluoride, sulphur and disulphur dichlorides, phosphorus trichloride in the liquid state cause potassium to combust. The same is true for phosphorus pentachloride in the solid state. In the latter case the same accident happened with gaseous halide. The same is also true for the bromide analogues of these compounds. 

When potassium tert-butylate in the solid state comes into contact with a few drops of methanol, ethanol, or 1- or 2-propanol it causes the alcohols to combust after a latency period of two, seven, and one minute(s) respectively. If the alcohol is in the vapour state, ignition can also take place. However, if there is a large quantity of alcohol, there is no incident since alcohol in excess absorbs the heat produced. 

Finally, chromium trioxide in the solid state causes alcohols with which it comes into contact to combust immediately. Accidents are reported with methanol. 

DMF is often used as a solvent in oxidation reactions. Thus, in the reaction below, the medium combusts when chromium trioxide in the solid state comes into contact with the reagents ... 

Dimethyisulphoxide combusts when it comes into contact with potassium permanganate in the solid state. 

Such is the richness and intellectual vibrancy of the field of RI chemistry that an additional book was needed to cover silicon, germanium and tin centered RFs, as well as tetrahedral intermediates and topics of increasing importance such as quantum mechanical tunelling, conical intersections, solid-state chemistry, and combustion chemistry. These topics are covered in this new book. 

Long-range atmospheric transport of Hg from fossil fuel combustion and solid waste incineration has increased Hg in freshwater and biota. In the United States, combustion of fossil fuels for power generation is estimated to generate about 30% of the total release of Hg into the atmosphere (Harriss and Hohenemser, 1978). One in every three lakes in the United States and nearly one-quarter of the nation s rivers contain various pollutants, including Hg (CNN, 2004). Forty States in the U.S. have issued advisories for methylmercury on selected water-bodies, and 13 states have statewide advisories for some or all sportfish from rivers or lakes (USGS, 2000). Fish consumption advisories for methylmercury account for more than three-quarters of all fish consumption advisories. 

Julien, C., Camacho-Lopez, M. A., Mohan, T., Chitra, S., Kalyani, P., Gopukumar, S., Combustion synthesis and characterization of substituted lithium cobalt oxides in lithium batteries, Solid State Ionics 135, 241-248 (2000). 

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