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,...

Read More

Share |

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...

Read More

Share |

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...

Read More

Share |

Refinery Hydrogen Management

by Alan Zagoria, Solutions & Services Introduction Refiners today are finding that hydrogen is one of the most critical challenges facing them as they plan production of clean fuels. In addition, hydrogen management practices significantly impact operating costs, refinery margin, and CO2 emissions. Therefore, an effective hydrogen management program must address refinery-wide issues in a systematic, comprehensive way. Managing hydrogen more effectively has been found to improve refinery profitability by millions of dollars a year, often enabling the refiner to avoid the capital cost of new hydrogen production. The hydrogen system consists of producers, purification processes, consumers, and the distribution network itself. Daily operating decisions impact the performance of the hydrogen...

Read More

Share |