Process Analytical Chemistry, necessity for the modern industry and environment
Ari Ivaska and Johan Bobacka
Process Chemistry Centre, c/o Laboratory of Analytical Chemistry,
Abo Akademi University, FI-20500 Turku/Abo, Finland
Technological development in the chemical industry has gone towards automation and computer control of manufacturing processes. Monitoring and control of emissions to the environment are also automated to a large extent. This is valid for both continuous and batch processes. Computer control is applied to optimize the use of the processing capacity of the plant, raw materials and energy. With proper control even processes that without control would be unstable can be stabilized. All these operations require monitoring the material and energy streams as well as measurement of concentrations of the compounds that are involved in the process.
During the recent years process automation has developed considerably. However, the analytical measurements required to perform all the automatic operations are often from “stone age” compared with the used automation and information technology. Many of the analytical methods still used are based on the same technology that is used in laboratory environments and therefore are not well suited for measurements in harsh process environments. Therefore development of the analytical methods for process industry is of great importance and has led to development of a new scientific discipline: Process Analytical Chemistry, which is in the crossroad of Chemistry and Chemical Engineering. Process analytical chemistry is based on traditional analytical chemistry but it uses process technology, electronics, mathematics and information technology in developing analytical methods for in-line and on-line methods for continuous analysis of the main and by-products as well as process and effluent streams. Especially the use of chemical sensors will be more important in the future.
The main targets and challenges of modern analytical chemistry, and Process analytical chemistry in particular, is the development of robust and automatic analytical systems that can be used in process applications. Computer controlled instrumentation can collect a vast amount of data from even simple measurements and sophisticated mathematical methods and algorithms are needed to extract the relevant information from the acquired data and to group the analytical results in specific patterns. Determination of low concentrations is an everlasting challenge but the demand for accurate determination of high concentrations in complex industrial sample matrices is as important in many processes. Speciation of elements in a particular sample is becoming more important as well as the spatial distribution of elements in solid samples. The process analytical methods do not necessarily have to be specific or accurate but they should have high reproducibility and repeatability. In many applications it is more important to follow changes in process parameters than to know their absolute values.