Combustion equipment

In modem Hquid-fuel combustion equipment the fuel is usually injected into a high velocity turbulent gas flow. Consequently, the complex turbulent flow and spray stmcture make the analysis of heterogeneous flows difficult and a detailed analysis requires the use of numerical methods (9). 

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. 

Fluiaized-Bea Boilers As explained in the earlier discussion of coal combustion equipment, the furnace of a fluid-bed boiler has a unique design. The system as a whole, however, consists mainly of standard equipment items, adapted to suit process requirements. The... 

Indirect-Fired Equipment (Fired Heaters) Indirect-fired combustion equipment (fired heaters) transfers heat across either a metallic or refractory wall separating the flame and products of combustion from the process stream. Examples are heat exchangers (dis-... 

Mobile sources include railroad locomotives, marine vessels, aircraft, and automotive vehicles. Over the past 100 years, we have gained much experience in regulating smoke and odor emission from locomotives and marine craft. Methods of combustion equipment improvement, firefighter training, and smoke inspection for these purposes are well documented. This type of control is best at the local level. 

Vanadium-Sodium Compounds Most Corrosive. Physical property data for vanadates, phase diagrams, laboratory experiments, and numerous field investigations have shown that the sodium vanadates are the lowest melting compounds and are the most corrosive to metals and refractories. These compounds are thought to form by either the vapor phase reaction of NaCI and V2O5 or by the combination of fine droplets of these materials upon the cooler parts of combustion equipment. 

Fuel Asb Corrosion Control. A variety of methods have been used to control fuel ash corrosion of metallic members in process furnaces, utility boilers, and other combustion equipment. Among these are ... 

Direct-fired combustion equipment is that in which the flamt of combustion are used to achieve the desired result by r and convection. Common examples include rotary kilns and open-hearth furnaces. Indirect-fired combustion equipment is that in wh e... 

Combustion equipment and controls ANSI, FIA, FM, NEPA, NSC, OIA, UL, USCG... 

All combustion equipment (oil, gas, solid fuel) requires primary air to support combustion and secondary air to permit adequate velocities in flue ways, etc. These requirements are governed by the minimum air/fuel ratio and operating flue-way parameters. There are also published recommended minimum requirements that are generally in excess of these. 

Combustion equipment can be set to give optimum efficiency at the time of commissioning but this condition will not be maintained. Wear and tear on control valves, partial blockage of filters, sooting of surfaces, etc. will all cause a fall in efficiency. To counter this, regular maintenance is desirable, and must include routine flue analysis and burner adjustment. 

Most combustion equipment is not controlled by means of a feedback from flue gas analysis but is preset at the time of commissioning and preferably checked and reset at intervals as part of a planned maintenance schedule. It is difficult to set the burner for optimum efficiency at all firing rates and some compromise is necessary, depending on the control valves used and the control mode (e.g. on/off, fully modulating, etc.). 

A flame trap is employed where premixed air and gas is used in combustion equipment and prevents the flame passing upstream into the pipe system. Flame traps should be situated as near as possible to the gas burner. This is so that the flame does not have a long pipe mn in which it might accelerate to such a speed as to form a detonation wave and make the trap useless. 

Combustion equipment, when first commissioned, can be set to operate at its optimum efficiency. With time, however, there will be a deterioration due to blockage of air filters and breather holes, wear in valve linkages, etc. Such changes may have safety implications if gas-rich firing is a consequence. 

American combustion equipment is frequently used. This tends to use Imperial units as well as degrees Fahrenheit and ounces per square inch pressure. 

European combustion equipment utilizes metric units but these are frequently non-Sl. For example, heat and power ratings often use calories and kilocalories/h instead of joules and watts. 

The supply of gas from storage or vaporizer to plant is usually governed down to a medium pressure of around 1.5 bar, for final reduction to 28mbar for butane or 37 mbar for propane. However, the versatility of LPG is such that plant and combustion equipment designers can, for specialized purposes, select virtually whatever pressures are most suitable for their requirements. 

With twin-flue design boilers, it is usual to have completely separate gas passes through the boiler with twin wetback chambers. It is then possible to operate the boiler on one flue only, which effectively doubles its turndown ratio. For example, a boiler rated at 20,000 kg/h F and A100°C may reasonably be expected to operate down to 2500 kg/h F and A100°C on oil or gas providing suitable combustion equipment and control is incorporated. If prolonged periods of single-flue operation become necessary. 

The chamber is externally insulated and clad. Combustion equipment for solid fuel may be spreader or traveling-grate stokers or by pulverized fuel or fluid bed. Oil and gas burners may be fitted either as main or auxiliary firing equipment. The boilers will incorporate superheaters, economizers and, where necessary, air preheaters, grit arresters, and gas-cleaning equipment to meet clean air legislation. 

Although some integration has taken place where the appliance or boilermaker has assumed responsibility for the combustion system, overall, specialist manufacturers of combustion equipment who have developed products for each application such as boilers, furnaces, kilns and dryers, etc. serve the market. The burner makers have manufactured products which provide a packaged solution to the combustion requirement, looking after not just the burners and controls but also the fuel supply system, which may involve pumping, heating of the fuel, filtration and other peripheral equipment and functions. 

This fortuitous infiltration is essential in otherwise unventilated buildings, since it allows ingress of air providing oxygen for us to breathe and for combustion equipment to burn. The infiltration is, however, effectively uncontrolled, and is often insufficient in quantity, at the wrong temperature or too contaminated to maintain satisfactory internal environmental conditions. 

Operators are required to maintain correct fuel pressures and ensure that the combustion equipment (burners, stokers, soot blowers, ash handling, etc., as appropriate) is in good working condition. 

George, A. M. Chemical Control of Slagging in Incinerators and Other Combustion Equipment. Marston-Bentley technical literature. Canning Group, P.L.C., UK, 1993. 

Dual Alkali A flue-gas desulfurization process. The sulfur dioxide is absorbed in aqueous sodium hydroxide and partially oxidized, and this liquor is then treated with calcium hydroxide to regenerate the scrubbing solution and precipitate calcium sulfate. Developed by Combustion Equipment Associates and Arthur D. Little. 

Fixed carbon is the combustible residue left after the volatile matter is driven off. It is not all carbon. Its form and hardness are an indication of fuel coking properties and, therefore, serve as a guide in the selection of combustion equipment. Generally, fixed carbon represents that portion of fuel that must be burned in the solid state. 

To assist in the location of air inlets for ventilation systems and combustion equipment... 

Kerr-HcGee Chem. Corp. Trona, CA Combustion Equip. Assoc. Coke/Coal/Oil 0.5-5. Sulfur... 

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