Thermal efficiency conversion

Biomass whether trees, plants, grasses, algae, or water plants, has a heating value of 15.1 X 10 J/dry t, and is converted in integrated biomass planting, harvesting, and conversion systems to SNG at an overall thermal efficiency of 50%. 

Another hydrogenation process utilizes internally generated hydrogen for hydroconversion in a single-stage, noncatalytic, fluidized-bed reactor (41). Biomass is converted in the reactor, which is operated at about 2.1 kPa, 800°C, and residence times of a few minutes with steam-oxygen injection. About 95% carbon conversion is anticipated to produce a medium heat value (MHV) gas which is subjected to the shift reaction, scmbbing, and methanation to form SNG. The cold gas thermal efficiencies are estimated to be about 60%. 

Synthetic jet fuel derived from coal is even more difficult and expensive, since the best of the conversion processes produces a fuel very high in aromatics. With hydrogenation, overall thermal efficiency is only 50%. Without additional hydrogenation, the gas turbine fuels would contain 60—70% aromatics. 

In another example Newby et al. [6] calculated a cycle with the reformer operating at comparable pressure and temperature but with a higher recycling rate of 1.7, leading to a conversion rate of a = 0.56 (this is closer to the conversion rate of Lloyd s steam/TCR cycle, a = 0.373, described in the last section). A thermal efficiency of 38.7% is claimed for this FG/TCR cycle, slightly greater than the simple CBT cycle efficiency of 35.7% but much less than the calculated efficiency for the steam/TCR cycle (48.7%) and a comparable STIG cycle (45.6%). 

Hie best overall efficiency of a turbine can be ensured by maintaining tile efficiency of the air compressor section. Conversely, allowing the air compressor efficiency to deteriorate will deteriorate the overall thermal efficiency of the turbine. Air compressor efficiency can be draslically reduced in a very short time when dirt, salt water mist, or similar air con-... 

Pressure/vacuum, 435, 466 Vacuum systems, 343 Absolute pressure conversions, 363 Air inleakage, 366 Calculations, 366-375 Dissolved gases release, 368 Estimated air inleakage, table, 366 Evacuation time, 371 Maximum air leakage, chart, 367 Specific air inleakage rates, 368 Temperature approach, 375 Classifications, 343 Diagrams, 380 Pressure drop, 353 Pressure levels, 343, 352 Pressure terminology, 348 Pump down example, 381 Pump down time, 380 Thermal efficiency, 384 Valve codes, 26... 

The efficient conversion of the furazans (70) into 1,4-dinitriles (71) is thought to occur via the nitrile oxides (72). Thermal decomposition of the diaziridones (73) in the presence of triethyl phosphite gives the phosphine-imine (75) and the isocyanate (74), which subsequently react together to give the carbodi-imide (76). ... 

Chemical reaction has potential for both efficient energy conversion and storage. This part shows possibility of efficient thermal energy storage and thermal energy conversion methodologies by chemical reaction. 

Hundreds of cycles have been studied from the viewpoint of the feasibility of component chemical reactions in terms of conversion ratio or product separation, theoretical thermal efficiency of hydrogen production, etc. [16]. Among them, those that utilize thermal decomposition of sulfuric acid, which are categorized as "sulfur cycles," have been considered one of the most promising cycles. 

The thermal efficiency of an energy conversion device is defined as the amount of useful energy produced relative to the change in stored chemical energy (commonly referred to as thermal energy) that is released when a fuel is reacted with an oxidant. 

The processor was operated at atmospheric pressure and at 117—130 °C or 200 °C. A methanol-water mixture (1 1.5 molar ratio) was fed at 0.1 cm /h using a syringe pump. The reactors loaded with powder and pellets had comparable results, but the researchers preferred the powder packed bed form for its smaller volume and mass. The best hydrogen production was obtained at low temperatures, providing, on a dry gas basis, 70% hydrogen, 0.5% carbon monoxide, and residual carbon dioxide. Methanol conversion or thermal efficiency was not reported. 

Since the oceans comprise over 70% of the earth s surface area, the absorbed solar energy that is stored as latent heat of the oceans represents a very large potential source of energy. As a result of variation in the density of ocean water with temperature, the ocean water temperature is not uniform with depth. Warm surface ocean water with low density tends to stay on the surface and cold water with high density within a few degree of 4°C tends to settle to the depths of the ocean. In the tropics, ocean surface temperatures in excess of 25° C occur. The combination of the warmed surface water and cold deep water provides two different temperature thermal reservoirs needed to operate a heat engine called OTEC (ocean thermal energy conversion). Since the temperature difference of the OTEC between the heat source and the heat sink is small, the OTEC power plant cycle efficiency... 

The suitability of a cycle for hydrogen production depends upon the overall thermal efficiency and operational feasibility. A highly endothermic reaction step is required in a cycle to achieve effective heat-to-chemical energy conversion. For efficient mass and momentum transfer a fluid based system is preferred [96] and, ultimately, for large-scale hydrogen production other factors such as environmental effects and cost effectiveness must also be considered. 

Fig. 13. Thermal efficiency of fossil-fuel operated luel-cell power plants compares favorahly with cnnseniinnat means ni energy conversion The efficiency is reduced in small units mainly because of losses in Ihe fuel processing...

OCEAN THERMAL ENERGY CONVERSION (OTEC). Utilization of ocean temperature differentials between solar-heated surface water and cold deep water as a source of electric power. In tropical areas such differences amount to 35-40°F. A pilot installation now operating near Hawaii utilizes a closed ammonia cycle as a working fluid, highly efficient titanium heat exchangers, and a polyethylene pipe 2000 feet long and 22 inches inside diameter to handle the huge volume of cold water required. Alternate uses for such a system, such as electrolysis of water,... 

A recent modification (1-3) of the conventional model ( 4) for photoelectrochemical reactions suggests that photo-generated minority carriers may, under certain conditions, be injected into the electrolyte before they reach thermal equilibrium within the semiconductor space charge layer. This process is called "hot carrier injection. More efficient conversion of optical energy into chemical energy may be possible with hot carrier injection because a greater fraction of the incident photon energy can be deposited in the electrolyte to do chemical work. 

The energy requirements of the three sections (using the modified Neumann model for the iodine section) are gathered in Table 1. Using a heat to electricity conversion factor of 50%, they correspond to a cycle thermal efficiency of 39.3%. 

We have our work divided into process engineering, process chemistry, catalysis, and support technology. As an example, one of the indirect liquefaction projects, tube wall reactor, deals with the design and operation of high thermal efficiency catalytic reactors for syn-gas conversion. Other activities are coal liquefaction properties of coal minerals, the role of catalysts, coal liquid product stability, and environmental impact—to name a few. 

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