New ideas for energy savings – Creative thoughts on \"Some ideas regarding energy savings in catalytic devices\"

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The catalytic cracking (FCC) unit is a core facility in refineries and petrochemical plants. The energy consumption of such units typically accounts for 25% to 35% of the total energy consumption of the entire plant, with this figure sometimes reaching as high as 50%. The average energy consumption is 2500–3500 MJ per ton, and heat loss alone amounts to 400–500 MJ per ton; thus, catalytic cracking units are by far the largest consumers of energy among refinery facilities. Therefore, ensuring the safe operation of catalytic equipment and reducing the energy consumption of catalytic cracking units is of great significance for improving the social and economic benefits of oil refining enterprises. In catalytic equipment, SOX and NOX present in flue gas condense on the wall surfaces, causing dew point corrosion and stress cracking. To prevent such phenomena, the equipment housings of the regeneration systems in modern catalytic cracking units are designed with hot walls; the wall temperature is typically between 200 and 220°C, and can reach up to 250°C in some cases. If the wall temperature of the equipment and pipes is too high, heat loss increases, resulting in higher energy consumption for the system. Moreover, although this approach seems to solve the problem of dew point corrosion on the surface, in reality, in the face of extreme weather conditions such as blizzards in the north and heavy rainfall in the south, the exposed metal walls still end up dropping below the dew point temperature for a considerable period of time, leading to dew point corrosion. Therefore, the author has an idea that, if implemented, could significantly reduce the heat dissipation of catalytic equipment and also address the issue of dew point corrosion encountered earlier. This idea involves applying an external insulation layer around the metal walls, acting like a coat that prevents direct contact between the metal walls and extreme weather conditions, thus maintaining the temperature of the metal walls at 160°. If the temperature of the metal wall can be maintained at the ideal level of 150–160°, and since the temperature at which dew point corrosion occurs is generally around 130°, this temperature can completely prevent the occurrence of dew point corrosion. At the same time, external insulation can also completely prevent extreme weather conditions from affecting the temperature of the equipment’s outer wall. After insulating layering is applied to the outer wall of the catalytic equipment, calculations show that the outer wall temperature can be reduced to 80° or even lower. With an ambient temperature of 20°, the heat loss can be reduced by 66% compared to when the metal wall is exposed at 200° without any insulation, resulting in an impressive energy-saving effect. To maintain the outer wall temperature at 160°, it is first necessary to thicken the equipment lining or improve its insulating properties, in order to reduce the outer wall temperature from around 200° at present to 120°. Previously, catalytic devices were designed with cold walls, and the wall temperature was generally around 120°. Later, to avoid dew point corrosion, hot wall designs were adopted, which raised the temperature to the current level of 200°. Achieving this goal is not too difficult; the existing manufacturing processes can be used for that purpose. When applying external insulation to the outer wall, attention should be paid to protection against excessive wall temperature. If damage occurs to the lining and this leads to an increase in the temperature of the metal casing, it is advisable to make corresponding adjustments to the external insulation layer, such as changing its color ； Or it may fall off, achieving the effect of cooling the outer wall at the site of detachment.