Tubular reactors are used in a continuous flow mode with reagents flowing in and products being removed. They can be the simplest of all reactor designs. Tubular reactors are often referred to by a variety of names
Single-phase flow in a tubular reactor can be upward or downward. Two-phase flow can be co-current up-flow, counter-current (liquid down, gas up) or, most commonly, co-current down-flow.
Tubular reactors may be empty for homogenous reactions or packed with catalyst or other solid particles for heterogeneous reactions. Packed reactors require upper and lower supports to hold particles in place. Upper packing often includes inert material to serve as a pre-heat section. Pre-heating can also be done with an internal spiral channel to keep incoming reagents close to the heated wall during entry, as shown to the right. It is often desirable to size a tubular reactor to be large enough to fit 8 to 10 catalyst particles across the diameter and be at least 40-50 particle diameters long. The length to diameter ratio can be varied to study the effect of catalyst bed length by equipping the reactor with “spools” placed in the bottom of the reactor to change this rati
Tubular reactor systems are highly customizable and can be made to various lengths and diameters and engineered for various pressures, temperatures and materials of construction. A split-tube furnace is provided for heating these vessels. Insulation is provided at each end, to minimize heat loss and prevent the end caps from being heated. The heater length is normally divided into one, two, or three separate heating zones, although it can be split into as more zones if required.