Process tubes in refining applications are typically steel alloy (ASTM A335 P22, P5 or P9), which contain 2.25%, 5% and 9% Cr, respectively. These grades oxidize at operating temperatures, and scale will grow continuously on the surface, often reaching 2 mm in thickness in higher-temperature/high-heat-flux units. The layers of scale are very insulating and represent a significant barrier to conductive heat transfer to the process.
Dingankar, S.,
Mahulkar, S., Reliance Industries Ltd.;
Schutt, M.,
Mahalingam, S., TechnipFMC;
Banerjee, S., Technip India Ltd.
Process engineers strive to recover as much energy as is practically possible from the available process and utility streams within the constraint of the plant. To achieve this goal, traditional—and sometimes non-traditional—methods are utilized. In a steam cracker, light olefins are considered the highest-value products, and utilizing “cold energy,”
Achieving effective catalyst regeneration requires a process that produces a very high level of heat in a very efficient manner. Over the years, several different approaches have been taken to create this required heat. Traditional steam has been a popular choice, as has heated transfer media. However, these methods have limitations.
All the book learning in the world will fail if we do not use common sense. We could also say that we need to think things through and should recognize that intuitive logic can lead us astray. If that sounds like semantic banter, let us zero in on three practical field examples that illustrate the issues at hand.
As environmental regulations are becoming more stringent on reduced nitrogen oxide and carbon monoxide emissions, burner designs are changing to meet revised regulations. The heater design must complement the chosen burner for optimal performance. Although design duty is considered to be the main focus of the heater design, the range of heater operation and its impact on heater safety and emissions needs are often neglected.
In the production of clean fuels, plastics and other hydrocarbon-based products, refineries and petrochemical facilities generate unwanted (waste) byproducts. Having no market value, the undesired byproducts must be recycled, minimized or eliminated. Depending on the feedstocks, end products and reactant materials, the unwanted materials can be gases, liquids or multiphase materials.
From refining to chemical production processes, heaters play an essential role in hydrocarbon processing applications.
Whether it is heating process fluids to achieve enough temperature in crude atmospheric and vacuum distillation units, or reaction temperatures inside furnace tubes to produce ethylene, vinyl chloride monomer, synthetic gas and continuous catalytic reformer reactors, or simple process heating (thermal fluid), process furnaces play a critical role in refineries and petrochemical complexes.
Ethylene is a precursor to many chemicals, fibers and plastics that are used in daily life.
Refineries cannot afford a sudden boiler failure (FIG. 1). Regularly assessing the condition of boilers is vital.