Oxygen combustion efficiency

In the complicated reaction networks involved in fuel decomposition and oxidation, intermediate species indicate the presence of different pathways that may be important under specific combustion conditions. While the final products of hydrocarbon/air or oxygenate/air combustion, commonly water and carbon dioxide, are of increasing importance with respect to combustion efficiency—with the perception of carbon dioxide as a... 

Results of an experimental program in which aluminum particles were burned with steam and mixtures of oxygen and argon in small-scale atmospheric dump combustor are presented. Measurements of combustion temperature, radiation intensity in the wavelength interval from 400 to 800 nm, and combustion products particle size distribution and composition were made. A combustion temperature of about 2900 K was measured for combustion of aluminum particles with a mixture of 20%(wt.) O2 and 80%(wt.) Ar, while a combustion temperature of about 2500 K was measured for combustion of aluminum particles with steam. Combustion efficiency for aluminum particles with a mean size of 17 yum burned in steam with O/F) / 0/F)st 1-10 and with residence time after ignition estimated at 22 ms was about 95%. A Monte Carlo numerical method was used to estimate the radiant heat loss rates from the combustion products, based on the measured radiation intensities and combustion temperatures. A peak heat loss rate of 9.5 W/cm was calculated for the 02/Ar oxidizer case, while a peak heat loss rate of 4.8 W/cm was calculated for the H2O oxidizer case. 

Fluidized-bed combustion systems use a heated bed of sandlike material suspended (fluidized) within a rising column of turbulent air to burn many types and classes of waste fuels. The vendor claims that this technique results in improved combustion efficiency of high moisture content fuels and is adaptable to a variety of waste -type fuels. The scrubbing action of the bed material on the fuel particle is said to enhance the combustion process by stripping away the carbon dioxide and char layers that normally form around the fuel particle. This allows oxygen to reach the combustible material much more readily and increases the rate and efficiency of the combustion process. 

While this paper will concentrate on oxygen sensors as used in automotive applications, there is increasing interest in their use in the measurement and control of industrial and other furnaces in order to reduce fuel costs by maximizing the combustion efficiency. They have also been used for many years to measure the oxygen content of molten glass, of molten steel and other metals and for numerous other applications where a measurement of the oxygen partial pressure is desired. 

As air temperature increases, air density decreases. This results in a reduction in the amount of oxygen available per unit volume of air to aid in the combustion of fuel. FIGURE 4-1 demonstrates the loss in fuel combustion efficiency as ambient air temperature increases. As shown, a loss of combustion efficiency occurs as intake air temperature increases above 90°F (32.2 C). A similar reduction in efficiency occurs with increasing altitude. 

That carbon may enter into these two combinations with oxygen is of utmost importance in the design of combustion equipment. Firing methods must assure complete mixture of fuel and oxygen, to be certain that all of the carbon bums to CO and not to CO. Failure to meet this requirement will result in appreciable losses in combustion efficiency and in the amount of heal released by the fuel, since only about 28% of the available heat in the carbon is released if CO is formed instead of CO . 

Figure 1. Liquid synthetic fuel combustion test combustion efficiency vs. excess oxygen. 40 MW, 6 burners in service.

RFC contains 2 percent by weight oxygen additives (oxygenates), such as MTBE or ethanol. Oxygenates increase the combustion efficiency of gaso-... 

The above simplified analysis was intended to provide a feel for the relative importance of the processes that govern carbon loading, and therefore carbon combustion efficiency. More complete treatments of AFBC s are available which consider the detailed population balance equations for the char particles coupled with an oxygen balance (41-50). These treatments have given results which parallel observations on operating AFBC s but... 

Heat Max Temp (°C) Oxygen (%) Equivalence Ratio 0 Combustion Efficiency... 

Monitoring regimes (measurement and recording of combustion temperature continuous monitoring of excess oxygen, CO emissions and combustion efficiency, etc.). 

The development of mathematical models to describe the thermochemical process occurring in a fluidized bed involves setting up the material and energy balance equations. The total process is represented in terms of a set of independent equations which are solved simultaneously to obtain such quantities as combustion efficiency, sulfur retention, oxygen utilization, oxygen and sulfur dioxide concentration profiles in the bed, etc. 

The parameters that need special consideration for the successful coupling on an SFC to a CLND are restrictor position, ozone generation, combustion efficiency (temperature and oxygen flow rate), and quenching. Each of these will be discussed in detail. 

Various types of polymers are used to formulate propellants and explosives. The nature of polymers is identified by their chemical bond structure. Two types of copolymers are used to formulate modern propellants and explosives (1) polyurethane copolymer and (2) polybutadiene copolymer. The chemical bond structures of polyether and polyester are used for polyurethane copolymers. Since the molecular concentration of oxygen is relatively high for polyurethane binder, this class of binder is used to achieve high combustion efficiency with low oxidizer concentration of crystalline materials. On the other hand, the heat of formation of polybutadiene copolymer is high and the molecular concentration of oxygen is low when compared with polyurethane copolymer. This class of binder is used to achieve a high combustion temperature when mixed with crystalline oxidizer particles. 

---