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.

Continuous flow reactors: a perspective

“…82 Due to the specific nature of these sensors, they are relatively inexpensive and therefore demonstrate great potential for the monitoring of continuous flow processes. Ebrahimi et al 84 investigated the production of unstable percarboxylic acids which find application as oxidisers in bleaches and disinfectants; comparing the safety rating with a batch process. In addition, the authors explored the possibility of developing micro processing systems to enable customers to generate the compounds at the point of use, concluding that this mode of operation would reduce the hazards, costs and environmental burden associated with transportation of these unstable materials.…”

Continuous Flow Epoxidation of Alkenes Using a Homogeneous Manganese Catalyst with Peracetic Acid

“…These reactions were conducted at room temperature; as shown by other studies, higher temperatures would enable shorter residence times. 28,41,42 Catalytic Flow Studies. Initially, a system with three pumps was employed: one pump introduced PAA R (preprepared), a second pump delivered a stock solution of substrate and catalyst, and a third pump was used to continuously add an aqueous solution of sodium thiosulfate as a quench stream (Figure 2).…”

Simultaneous determination of enthalpy of mixing and reaction using milli-scale continuous flow calorimetry

“…In addition, continuous reactors are smaller for the same production capacity since higher temperatures and pressures allow a shorter residence time than batch reactors [3]. The heat transfer is better in a continuous flow reactor and there is less potential chemical energy, so the consequences of an incident are drastically reduced [4]. For the safety assessment of a process, the determination of the enthalpy of reaction is an elementary component [5,6].…”