Working Principle of Laboratory Reactors

　　A laboratory reactor is a piece of equipment used to carry out chemical reactions in an industrial setting. It enables systematic studies of single-phase liquid reactions as well as multiphase chemical reactions involving gas-liquid, gas-liquid-solid, and gas-liquid-solid systems. The reactor typically features a stirring device (such as mechanically driven stirrers or stirrers operated by gas flow). When the reactor has a relatively large height-to-diameter ratio, multi-stage impellers can be employed. During the reaction process, if heating or cooling of the materials is required, jacketed coils can be installed on the reactor walls, and heat-exchanging surfaces can be incorporated inside the reactor. Alternatively, heat exchange can also be conducted in an external circulation system.

　　Classified according to laboratory reactor operating procedures

　　1. Laboratory reactor vessel

　　It features flexible operation and is easily adaptable to various operating conditions and product varieties, making it suitable for producing small batches of multiple product types with long reaction times. The drawback of batch reactors is that they require auxiliary operations such as feeding and discharging materials, which can lead to unstable product quality. However, in certain reaction processes—such as fermentation and polymerization—continuous production remains difficult to achieve, so batch reactors are still widely used today.

　　In a laboratory reactor, the raw materials are added at a fixed ratio in a single batch. Once the reaction reaches the desired specifications, the raw materials are discharged in one go. In a continuous-reactor system, raw materials are continuously fed in, and reaction products are continuously removed. When the operation reaches a steady state, the state parameters—such as composition and temperature—of the material at any given point within the laboratory reactor no longer change over time. A semi-continuous reactor, also known as a semi-batch reactor, typically involves adding one reactant in a single batch while continuously feeding in the other reactant. After the reaction has reached the required conditions, the operation is stopped, and the materials are removed.

　　The advantages of laboratory reactors include their simple equipment design and the ability to use the same control system for a variety of technical products across different production processes in enterprises. They are particularly well-suited for small-batch, multi-variety production in Chinese industrial sectors such as pharmaceuticals and dyes. Additionally, batch reactors do not involve material recirculation, which is beneficial for most students conducting reactions. However, the disadvantages include the need for auxiliary processes such as material loading, unloading, and cleaning, making it difficult to maintain consistent product quality.

　　Laboratory reactor or continuous reactor

　　Although the drawbacks of intermittent operation can be avoided, under the influence of stirring, the fluid inside the vessel will become thoroughly mixed. When mixing is vigorous, the liquid viscosity is low, or the average residence time is long, the flow pattern within the reactor can be regarded as completely mixed flow; hence, the reactor is referred to as a completely stirred tank reactor. In cases involving high conversion rates or side reactions occurring in series, a multi-reactor system can be employed to mitigate the adverse effects of backmixing and enable precise control over reaction conditions.

　　Continuous reactors should be used whenever possible for large-scale production. The advantages of continuous reactors include stable product quality and convenient operation. However, a drawback of this approach is the presence of varying degrees of backmixing within continuous reactors, which can be detrimental to most reactions and thus should be carefully controlled through appropriate reactor selection and structural design.

　　The above is an introduction to the working principle of laboratory reactors. If you’d like to learn more, feel free to contact us anytime! Our company has many years of experience and looks forward to having you join us at any time.