Classification of synthesis towers
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Classification of synthesis towers 1.1 Classified by the method used to remove reaction heat: 1.1.1 Internal heat-exchange type synthesis tower: Cold tubes are embedded in the catalyst layer, and the gas inside these tubes is used to cool the catalyst layer, thereby allowing the reaction to take place at a certain temperature. 1.1.2 Quench-type synthesis tower: The high-temperature gas resulting from the reaction is directly cooled using cold process gas, so that its temperature is reduced to a certain level before it proceeds to the next reaction stage. Depending on the requirements of the process, the catalyst layer is divided into N layers, and (N–1) quenching devices must be installed. To ensure uniform mixing of the quenched gas, a diamond distributor or other type of gas mixing device is installed inside the tower.
You are referring to it in terms of the ICI format; in fact, there are also the Casali and Luchi constant-temperature types, among several others. Relatively speaking, it’s much easier to operate than what you mentioned, with just less catalyst needed.
Synthesis towers can also be classified according to the flow pattern of the gas within the internal components (the catalyst baskets): 1. Fully axial synthesis tower； 2. Fully radial type synthesis tower ； 3. Axial radial mixed-flow type synthesis tower. Classified by the method of removing reaction heat, in addition to the two methods mentioned by the original poster, there should be another one: a combination of inter-layer heat transfer and cooling shock.
Please refer to the synthesis tower and the classification of internal components in synthesis towers. 1. Internal cooling type: Cold tubes are installed within the catalyst layer; these tubes utilize unreacted cold gas to remove the heat generated by the reaction, while also preheating the gas before it enters the reaction zone. Early synthesis towers were mostly of the internal cooling type. 2. Multi-layer insulated quenching type: The catalyst bed is divided into several sections, with quenching elements placed between these sections. Cold air that has not yet been preheated is used to enter the interlayer in order to lower the temperature of the reaction gas. 3. Multi-stage adiabatic – inter-stage heat exchange type: The catalyst is divided into several layers, with heat exchangers installed between these layers. Indirect heat exchange is achieved using cold water. 4. Composite type: Integrates the first three structures organically to leverage their strengths and compensate for their weaknesses. It is the development direction for the internal structure of synthesis towers nowadays.
Based on the direction of gas flow, they can be classified as follows: 1. Radial synthesis towers – In these towers, the gas flows radially through the catalyst layer. To ensure even gas distribution, gas distribution devices are used, and heat removal is achieved through condensation or internal cooling. 2. Axial synthesis tower: The gas flows axially through the catalyst layer, with various heat removal methods such as condensation, internal cooling, and inter-layer heat exchange being employed. 3. Axial-radial composite synthesis tower: The gas experiences both axial and radial flow, with internal cooling or heat rejection by cold injection employed. 4. Double layers combined to form a tower. Last edited by mtx71 on 2009-2-28 10:47.]