How to Optimize the Internal Structure Design of the Reactor Vessel Body of Batch-Type Pyrolysis Oil Refining Equipment

How to Optimize the Internal Structure Design of the Reactor Vessel Body of Batch-Type Pyrolysis Oil Refining Equipment

The core objectives of optimizing the internal structure design of the reactor vessel body of batch-type pyrolysis oil refining equipment are improving the uniformity of material heating, reducing local coking, enhancing the airtightness of the oxygen-free environment, and shortening batch operation time. The specific optimization schemes can be carried out from four dimensions: flow field guidance, material disturbance, anti-coking treatment, and interface adaptation, as follows:

Add Flow Guiding Structures to Optimize High-Temperature Gas Distribution

To address the problems of uneven flow of high-temperature gas inside the vessel and local heat accumulation, spiral flow deflectors or annular flow guide rings can be welded on the inner wall of the reactor vessel. Spiral flow deflectors can guide high-temperature gas to rise spirally along the axial direction of the vessel, allowing the gas to sweep evenly over the surface of the material layer and avoiding excessive pyrolysis caused by direct gas scouring of local areas. Annular flow guide rings can disperse the gas to different radial positions of the vessel, eliminating temperature difference dead zones characterized by "high temperature in the center and low temperature at the edges". The flow deflectors should be made of the same 310S stainless steel as the vessel body, with a thickness of 8–12mm, and the welding joints should be polished to prevent material adhesion and coking.

Install Low-Speed Agitation Devices to Strengthen Dynamic Material Heating

For piled bulk materials (such as waste tire blocks and plastic blocks), uniform heating cannot be achieved only by airflow heat exchange. A low-speed anchor-type stirring paddle should be installed at the bottom of the vessel, with the rotation speed set at 5–10r/min. This design can gently agitate the materials, enabling the bottom-layer materials to fully contact with high-temperature gas, while avoiding excessive dust generation caused by material fragmentation due to high-speed stirring. The connection between the stirring shaft and the vessel body must be equipped with high-temperature-resistant mechanical seals (such as flexible graphite seals) to prevent air infiltration during stirring, which would otherwise damage the oxygen-free environment. In addition, the blades of the stirring paddle should be designed in an arc shape to reduce rigid friction with materials and extend service life.

Adopt Anti-Coking Coatings and Inner Wall Polishing to Reduce Carbon Deposition Adhesion

Heavy components generated during pyrolysis tend to coke on the inner wall of the vessel, affecting heat transfer efficiency. Therefore, the inner wall of the vessel should undergo mirror polishing treatment to reduce surface roughness and minimize attachment points for heavy components. Meanwhile, a layer of high-temperature-resistant anti-coking coating (such as ceramic-based composite coating) should be applied. This coating has excellent non-stick and corrosion-resistant properties, which can effectively inhibit coking formation. The coating thickness should be controlled at 0.1–0.3mm and undergo high-temperature curing treatment to ensure long-term stable adhesion without peeling off under the 500℃ operating condition. In addition, steam purging ports can be arranged at the bottom of the vessel. After the completion of batch production, high-temperature steam can be introduced to soften and clean residual carbon deposits, shortening the time required for manual decoking.

Optimize the Positions of Feeding and Slagging Interfaces to Adapt to Batch Operation Processes

The feeding port should be adjusted from the traditional central position on the top to a side-mounted inclined feeding port on the upper head, equipped with a screw feeder to allow materials to slide down slowly along the inner wall of the vessel, avoiding local material accumulation caused by direct impact on the vessel bottom. The slagging port should be designed as a bottom conical structure with a taper of 30°–45°, utilizing gravity to realize rapid sliding of carbon black and reducing the workload of manual cleaning. Meanwhile, the sealing flanges of the feeding port and slagging port should adopt quick-opening locking structures to replace traditional bolt fastening, shortening the opening and closing time for feeding and slagging, and improving the effective operation efficiency of the equipment.