Key Structural Design Points of the Reactor Vessel Body

Key Structural Design Points of the Reactor Vessel Body

The structural design of the reactor vessel body for batch-type pyrolysis oil refining equipment must be centered around four core objectives: maintaining an oxygen-free environment, ensuring uniform heat transfer, enhancing structural strength and airtightness, and improving operational convenience. It directly determines the efficiency of pyrolysis reactions and the operational stability of the equipment. The specific design points are as follows:

Overall Configuration and Structural Strength Design

The vessel body preferably adopts a combined configuration of a cylindrical main body + arc-shaped heads. Compared with square structures, this design can disperse stress under high-temperature operating conditions, avoid deformation or cracking caused by local stress concentration, and adapt to the operating environment of high temperature (0–500℃) and slight negative pressure (≤0.02MPa). The connection between the heads and the cylinder body shall adopt a sealed structure of butt-welded flanges + bolt fastening. The weld seams must undergo non-destructive testing to ensure structural stability during long-term high-temperature operation and prevent gas leakage that would damage the oxygen-free environment.

Thermal Insulation and Heat Loss Control

The outer side of the vessel body shall be equipped with a multi-layer composite thermal insulation structure. The inner layer uses high-temperature-resistant aluminum silicate fiber felt, the middle layer is added with rock wool insulation layer, and the outer layer is wrapped with a galvanized steel plate protective shell to form an efficient thermal insulation barrier. This reduces heat loss from the inside of the vessel to the outside and lowers the energy consumption load of the temperature control system. Meanwhile, thermal expansion gaps shall be reserved in the insulation layer to avoid cracking and falling off of the insulation layer due to thermal expansion and contraction at high temperatures.

Optimization of Internal Flow Field and Uniform Heat Transfer

To address the problems of uneven heating of materials inside the vessel and local coking, guide plates or low-speed stirring devices need to be installed inside the vessel: Guide plates can guide high-temperature gas to flow evenly along the inner wall of the vessel body to form a circulating flow, enabling full contact between gas and materials; low-speed stirring paddles (with rotational speed controlled at 5–10r/min) can gently agitate materials, avoiding overheating of accumulated materials at the bottom and insufficient pyrolysis of materials at the upper layer. The stirring paddles shall be made of high-temperature-resistant alloy materials, and the shaft ends shall be equipped with seals to prevent air infiltration during the rotation of the stirring shaft.

Sealing Design of Feeding, Discharging and Slagging Interfaces

The feeding port and slagging port shall be arranged at reasonable positions of the vessel body (the feeding port is on the upper head, and the slagging port is at the bottom of the vessel body), equipped with sealed valves + quick-locking mechanisms. The interface flanges shall adopt a male-female face sealing structure, matched with high-temperature-resistant flexible graphite gaskets to ensure quick opening/closing and airtightness during batch operations, preventing air ingress during feeding and slagging that would damage the oxygen-free environment. The bottom slagging port shall be designed as an inclined structure to facilitate the rapid discharge of carbon black after pyrolysis and shorten the batch interval time.

Reserved Interfaces for Temperature and Pressure Monitoring

The vessel body shall reserve multi-point temperature and pressure measurement interfaces at different heights. Generally, 1–2 temperature sensor mounting holes are set at the upper, middle and lower parts of the vessel body respectively to collect temperature data of different regions in real time, providing a basis for gradient temperature control of the temperature control system. Meanwhile, pressure sensor interfaces are reserved to monitor pressure changes inside the vessel. In case of overpressure or negative pressure abnormalities, pressure relief or pressure supplement protection can be triggered in a timely manner. Welded sealed joints shall be used at the interfaces to prevent gas leakage.