Several questions regarding hydrogen production conversion furnaces
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As the title suggests: 1. The heat exchange in the convection section of the hydrogen production converter, 3.5 steam superheating, and the heat exchange with the raw gas entering the converter all employ a co-current approach, meaning that the inlet is located at the high-temperature end of the flue gas, while the outlet is at the low-temperature end. The reason for this design is unclear; it’s opposite to the usual approach to heat exchange. 2. When the temperature of the raw gas after heat exchange in the convection section exceeds 520°C, deoxygenated water is used for temperature control. May I ask: Is cooling deoxygenated water considered an abnormal or accident condition? Thank you.
Does it cool down at 520? Normally it’s at this temperature; previously, in order to raise the inlet temperature, we specifically didn’t need to lower the temperature of the convective chamber furnace tubes
1. Except that the raw gas inlet is located at the high-temperature end of the flue gas, the others are not. With this co-current design, as the flue gas temperature decreases, the temperature rise of the tube wall is more gradual, preventing the furnace tubes from overheating. 2. It should be an abnormal condition to use deoxygenated water for temperature control; otherwise, raw materials at high temperatures for a long time will undergo cracking and release carbon, which can easily lead to carbon deposition on the catalyst at the inlet.
This is related to the properties of the raw materials; an excessive amount of recombined components can lead to cracking and carbon release. For methane, the inlet temperature can be set at a higher level; we use natural gas, and the preheating temperature is 630°C.
1. If the temperature is sufficient, either co-current or counter-current operation will suffice; using co-current operation can reduce the wall temperature, thereby lowering the equipment costs associated with material selection. 2. Cooling deoxygenated water is used in cases where special operating conditions apply