Fuel firing efficiency, improvement

Measures such as improved process design, operation, maintenance, housekeeping, and other management practices can reduce emissions. By improving combustion efficiency, the amount of products of incomplete combustion (PlCs), a component of particulate matter, can be significantly reduced. Proper fuel-firing practices and... 

With these objectives in mind, the focal discussions in this book center around five kinds of energy improvement opportunities. The first is minimizing heat losses via diligence. In reality, steam generated in the boiler house is distributed through an extensive network of steam pipelines to end users. The losses in steam distribution can be 10-20% of fuel fired in boilers. Hence, the net boiler efficiency could be 10-20% lower from the user s point of view. 

Improvement of efficiency in electricity generation from fossil fuel-fired thermal systems ... 

Many kilns that formerly were direct coal-fired or producer-gas verticals were retrofitted to natural gas firing with center-burners and after World War II, dramatically improving lime quaUty, kiln capacity, and fuel efficiency. By the 1960s, this improved vertical kiln had lost favor to rotary and other special kilns because of the supply and cost problems of oil and gas in the United States and the spectacular improvement in rotary kiln performance. Many natural gas-fired center burners were permanently closed and dismanded because they could not be converted to coal. However, the reverse occurred in Europe where the extensive oil and gas discoveries heightened interest in the new, advanced vertical kilns. 

Fossil-fuel and wood-waste fired industrial and commercial fuel combustion units commonly use multiple cyclones (generally upstream of a wet scrubber, ESP, or fabric filter) which collect fine PM (< 2.5 im) with greater efficiency than a single cyclone. In some cases, collected fly ash is reinjected into the combustion unit to improve PM control efficiency (AWMA, 1992 Avallone, 1996 STAPPA/ALAPCO, 1996 EPA, 1998). 

Boilers may be direct fired or indirect fired. Energy supply designs account for various combustion methods using fossil fuels, municipal waste, process residues, waste heat, and by-products. Special boiler combustion systems to reduce pollution or improve efficiency include fluidized-bed and combined cycle. 

Fire tube boilers (shell boilers or shell and tube boilers) convert heat from burning fuel within a furnace (combustion chamber, firebox, or furnace tube) to generate either HW or steam. Fire tube boilers are designed to direct the combustion gases through tubes (held within tube sheets) that are surrounded by BW, thus providing for a greater heat-transfer surface area and improved efficiency. 

Fuel treatments have been used for very many years as an aid to improving the combustion efficiency process. Old formulations often used saw dust, wood flour, common salt, zinc sludge, ground oyster shell, and similar crude ingredients, but could still provide a dramatic effect when thrown into a fire. The metallic salts present (sodium in salt, zinc in sludge, and calcium in shell) acted as catalysts that dramatically lowered the ignition temperature of soot deposits from around 1100 °F/590 °C to only 600 °C/315 °C the fire burned vigorously and the soot disappeared. 

More than 45% of the world s electricity is generated from coal and it is the major fuel for generating electricity worldwide. The known coal reserves in the world are enongh for consnmption for over 215 years, while the known oil reserves are only abont 39 times the world s consumption and the known natural gas reserves are about 63 times the world s consumption level in 1998. Coal is not only plentiful, but also economical. Advanced coal-fired power generation technologies should be developed worldwide to generate at minimnm economic coal, improve thermal efficiency and meet environmental requirements. 

There exists, in the literature on high internal phase emulsions, a small number of publications on possible applications of HIPEs, involving a diverse range of topics. The production of petroleum gels as safety fuels is one such example [124,125] this was mentioned in the section on non-aqueous HIPEs. The main advantage over conventional fuels is the prevention of spillage, which reduces the risk of fire in an accident. Also, studies on the flash-point of emulsified fuels [127] showed a considerable increase, compared to the liquid state, for commercial multicomponent fuels. In addition, there may be an enhancement of the efficiency of combustion of the fuel on emulsification, as it is known that a small amount of water in fuel can improve its performance [19]. 

---