Chemical Reactors

A chemical reactor is a purpose built container that holds a chemical reaction and keeps it under control so that raw materials turn into the wanted products. It forms the core of chemical engineering plus of every industrial process because it gives a space in which temperature, pressure, concentration and mixing are kept at set values - this raises the reaction rate, increases the yield and protects people and plant. Reactors are tailored to a given task and therefore differ greatly in shape, size and intricacy. In the batch version the charge is treated as a single lot, the vessel is emptied when the step is finished but also the cycle starts anew. In the continuous version feed enters without interruption and product leaves at the same steady rate. Other well known forms are the plug flow unit as well as the stirred tank unit. Each layout brings its own benefits and the choice depends on how fast the reaction proceeds, on demands for heat removal or supply and on the required output rate. Heat must be added or withdrawn, gases or liquids have to be moved, catalysts must be held in place, the contents need to be kept homogeneous or temperature or pressure excursions have to be sensed and corrected right away. Jackets or internal coils carry heating or cooling fluids so that the charge stays at the optimum value - they also prevent runaway when the reaction itself releases or absorbs large amounts of heat. Reactors serve the pharmaceutical sector, the petrochemical sector, food and beverage plants and manufacturers of fine or specialty chemicals. The objective is to obtain the largest possible output also the greatest economic return while keeping waste and risk low. Every design step has to respect the applicable environmental and safety rules.