Safety Advantages of On-Site Microprocesses

Abstract

Usually large-scale capacities are preferred in process industry because of the economics of scale. However, small capacities bring along several other advantages, which are emphasized especially in on-site production. By producing on-site, the transportation of dangerous chemicals can be avoided. Moreover, smaller on-site production processes also mean a step towards inherently safer technology. Microreactors represent a technology that efficiently utilizes safety advantages resulting from small scale. These safety advantages of microreactors in on-site production are studied in this contribution. Production of peracetic acid is used as a test case. This unstable and explosive chemical is used, e.g. in treatment of municipal wastewater and pulp bleaching. This study is based on comparison of a conventional batch process with the capacity of 170 kg/h and an on-site continuous microprocess producing 10 kg/h peracetic acid. Preliminary design of these processes was carried out. Four different methods were used to analyze the safety of the processes. It was found that the conventional methods for analysis of process safety might not be reliable and adequate for radically novel technology, such as microprocesses. This is understandable because the methods are partly based on experience, which is very limited in the connection of totally novel technology.