Manufacturing Processes

Chemical Manufacturing Methods: Batch vs. Continuous Processing

Chemicals are manufactured using one of two distinct methods: batch or continuous. A continuous operation requires a constant raw material feed to the process vessel and continual product withdrawal. A batch process, which is used by specialty chemical manufacturers, requires intermittent introduction of frequently changing raw materials, varying process conditions within the vessel, and different removal methods. In batch processing, vessels are often idle while waiting for raw materials or undergoing quality control checks and cleaning. Thus, emissions from batch processing are substantially different from those of continuously operating processes.

Because of this specialized nature of the business, specialty chemical manufacturers are typically small, averaging fewer than 100 employees. Batch processing is efficient and is often the only method of producing small quantities of chemicals to meet customer demands for specific products. Continuous operations are larger and often use batch-produced chemicals or polymers as raw materials to manufacture large volumes of chemicals and plastics.

Legislation and regulations that are based on performance characteristics of large continuous operations often have significant adverse impact on small batch processing operations. Batch processors must retain operational flexibility because they:

  • Develop products to perform the specific applications. Often a specialty manufacturer produces a prototype product for the customer to evaluate. The customer provides feedback that enables the manufacturer to modify the product. The cycle is repeated in rapid succession until the customer has a satisfactory product. In such a development project, the raw materials used might change for each iteration of improvement.
  • Supply low-volume demand. While some chemicals, including basic petrochemicals, are made in high-volume continuous process plants, for economic and technical reasons, most chemicals cannot be made using a continuous process. Small batches are not typically made using dedicated equipment, as the same equipment might be used for 10 or 20 different products.
  • Supply seasonal demand. Because many end products have seasonal uses, batch processed chemicals are often manufactured in a brief production campaign at a particular time of the year, which is often set by the customer. 
Return Home