Saturday, May 29, 2010

Burner Operating Characteristics

Burners are critical for the successful operation of industrial furnaces. Presented here is a set of equations that can be used to calculate characteristics of burner operation, including flame length, flame diameter, ignitability and flameout conditions. Equations are based on pre-mix burners operating at atmospheric pressure and firing natural gas only. Premix burners create short and compact flames compared to raw gas burners, and are designed to function with fuel-gas mixtures that have consistent specific gravity and composition. Burner requirements For direct-fired heaters to function correctly, burners must be capable of providing...
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Hydrogen Production By Steam Reforming

Management of the gas is critical for petroleum refiners Ray Elshout Energy, Systems Engineering Steam reforming of natural gas at petroleum refining facilities is the predominant means of producing hydrogen in the chemical process industries (CPI). Areas where hydrogen is heavily consumed include ammonia production, the cryogenics industry and methanol production (Table 1). Because hydrogen needs within various sectors of the CPI are at their highest levels in history, and are continuing to grow, an understanding of this method of hydrogen production and purification can be useful. A major percentage of hydrogen used in the CPI goes toward...
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Thursday, April 29, 2010

Relief Device Design

Pressure relief valves or other relieving devices are used to protect piping and equipment against excessive over-pressure. Proper selection, use, location, and maintenance of relief devices are essential to protect personnel and equipment as well as to comply with codes and laws. Determination of the maximum relief required may be difficult. Loads for complex systems are determined by conservative assumptions and detailed analysis. By general assumption, two unrelated emergency conditions caused by unrelated equipment failures or operator error will not occur simultaneously (no double jeopardy). The sequence of events must be considered. The development of relief loads requires the engineer to be familiar with overall process design, including the type of pump drives used, cooling water source,...
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Tuesday, April 27, 2010

Gasoline and LP-Gas Treating

Most gasoline and LP-gas streams contain sulfur in various forms and LP-gas and raw NGL streams also can contain carbon dioxide. Especially objectionable are hydrogen sulfide, mercaptans, and elemental sulfur. Gasoline containing hydrogen sulfide has objectionable odor and is corrosive. Mercaptans give an objectionable odor to gasoline and elemental sulfur makes the gasoline corrosive. Carbonyl sulfide in the LP-gas can hydrolyze and cause the product to become corrosive. A product containing the objectionable materials can be treated to remove the hydrogen sulfide, carbonyl sulfide, and elemental sulfur and to either remove the mercaptans or convert them to less objectionable compounds. Hydrogen Sulfide and Carbon Dioxide RemovalHydrogen sulfide and carbon dioxide can be removed from LP-gas...
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Tuesday, April 20, 2010

Burner Retrofit Considerations

Flame Envelope 1. Conventional raw gas and premix burners have luminous flames. The combustion reaction occurs within the visible flame boundaries. The flame envelope is defined as the visible combustion length and diameter. Ultra-Low NOx and latest generation burners have non-luminous flames. Much of the combustion reaction is not visible. The flame length and diameter are often determined by inserting a CO probe into the firebox and defining the flame envelope as CO concentrations greater than 50 ppm. 2. Ultra-Low NOx and latest generation burners have longer flame lengths than conventional burners. Longer flame lengths change the heat transfer profile in the firebox. Longer flame lengths can result in flame impingement on the tubes and mechanical supports. 3. The flame diameter is...
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