Download Process safety assesment using adiabatic and reaction

Process safety assesment using adiabatic and reaction calorimetry for sodium
borohydride as reducing agent in methanol
Sigurnosna procjena reaktanta natrij borhidrida kao reducensa u metanolu
korištenjem adijabatske i reakcijske kalorimetrije
Dario Klarić1, Sebastijan Orlić1, Franjo Jović1, Eugen Marcelić1
1 Pliva
Hrvatska d.o.o., TAPI R&D, API Pilot
[email protected]
Process safety assesment is a key aspect of process development with a goal of safely
transfering a process to production, without any kind of hazard or risk.
The main focus of research was made on the thermal risk that comes out of
unwanted, secondary reactions which occur when process conditions are uncontrolled,
whether the cooling of the reactor has failed, or taking into account different rates of
heat and mass transfer during the process scale-up.
Reaction calorimetry (RC-1), adiabatic calorimetry (ARRST) and process simulators
(Dynochem, Visimix) are usefull tools in obtaining data and process understanding.
Reaction calorimetry is a technique for gathering valuable kinetic data of exothermic and
endothermic events which give insight into process safety and hazard analysis by
quantifying the enthalpy of the reaction. Adiabatic calorimetry is used for testing the
process in conditions that are uncontrolled, by heating the reaction mixture with a
constant heat ramp while monitoring exothermic events.
In our research, exothermic reaction with significant pressure generation that occurs
when using sodium borohydride as a reducing agent in methanol as a solvent was
examined. Sodium borohydride is a commercially available reagent which is commonly
used for the selective reduction of organic molecules. It is readily soluble in water and
alcohols during which hydrogen and heat (ΔrH>300 kJ/mol) are being released. The
reaction measurements were conducted using Mettler Toledo RC-1 reactor at 0-5oC
under atmospheric pressure. Using adiabatic calorimetry it was concluded that no
unwanted reactions occur which allowed the prediction of safe conditions in case of
unstable reaction conditions.
With the data obtained from those tools, process simulators are used to build
reaction models that include wanted and unwanted reactions, allowing us to build
scenarios that could bring the process into dangerous and unstable conditions.