A tubular reactor is a continuous operation reactor with a high length-to-diameter ratio. Compared to a kettle reactor, the tubular reactor offers numerous advantages. It belongs to the plug flow reactor category, with minimal back mixing. The tubular reactor has a small volume, a large surface area to volume ratio, and a high heat transfer area per unit volume; it allows for control of residence time and segmented temperature control; and it is suitable for reactions and chemical production involving multiphase fluids and non-Newtonian fluids. The tubular reactor boasts many benefits, making it highly suitable for continuous chemical production.
Compared to traditional fixed-bed reactors, the coiled tube reactor has a larger heat exchange area within the tube side of the reactor, under the same volume shell. This allows for rapid removal of excess reaction heat, promotes forward reactions, enhances reaction conversion rates, effectively avoids catalyst deactivation, and extends the catalyst's lifespan.
The coiled tube reactor is structurally capable of meeting requirements for both radial and axial flow directions and can adapt to operating conditions with high demands for reactor pressure drop. The catalyst is easy to load and unload, and its heat transfer capability is over 50% higher than that of a tubular fixed bed reactor. By adjusting the temperature of the coiled medium, a gradient distribution can be achieved, and the reaction temperature can be controlled. Li emphasized particularly: "Based on this design approach, the distribution and arrangement of the coiled heat exchanger tubes have been optimized. Through simulation calculations, a form of staggered distribution with different rows in the same layer and different layers has been adopted, making the distribution of various media inside the heat exchanger more reasonable and maximizing heat utilization. Compared to traditional multi-strand coiled tube heat exchangers, the heat exchange efficiency is increased by about 15%.
The coiled tube reactor has been applied to various pilot plants, including those for the synthesis of ethylene glycol and olefin products. The change in reactor design allows for stricter pressure drop control and higher heat transfer efficiency on top of the existing operational processes, effectively addressing equipment over-limitation and manufacturing issues in large-scale plants.