Polymerization inhibitors and inhibitors
Inhibitors and retarders of polymerization of styrene units Distillation of styrene, even under vacuum, is always subject to unwanted polymerizations.
The flow sent to the purification section is always purified, but even with these purifications, there are styrene losses in this part.
In addition, in addition to styrene, ethylbenzene, toluene, and benzene, the purification unit feed contains a large number of by-products with high and unstable boiling points (in terms of polymerization). Their production is generally outside the scope of the catalyst and they are usually produced through the mechanism of free radical compounds such as naphthalene, diphenol, diphenyl methane, etc. All of these compounds in the distillation tower are related to styrene and heavy compounds reduce the overall efficiency of the process.
In the liquid phase, polystyrene without any triggering factor in the formation of the polymer chains. The polystyrene formed is generally soluble in its monomer, but not soluble at the point of gelling and above which polystyrene forms a highly viscous gel.
The purification part is one of the most sensitive areas of styrene units, which is in fact the most important bottleneck of this unit due to the improper performance of non-specialized polymerization retarders.
The main goal of any chemical program in this area is to reduce the growth of polymers and ultimately reduce the losses of styrene monomers.
To better articulate the available chemicals, it is first necessary to discuss the differences in concepts related to polymerization retarders and inhibitors.
An inhibitor reacts irreversibly and very quickly with free radicals in the system. The inhibitor can completely prevent polymerization but is used completely in a static test.
To maintain the vacuum in the dehydrogenation of styrene units, hydrogen and other gases must be removed. To achieve this, the units usually use screw-type compressors that do not have oil. Although these compressors do not fill on their own, in most operating units a small amount of styrene monomer is transferred to them through separators. In the compressor, this phenomenon causes an increase in temperature and consequently polymerization in the vapor phase in the compressor itself and in the liquid phase in the cooling condensate discharge. (Popcorn deposits)
The fulling control switch is a suitable chemical application in the compressor suction section using a nozzle.
These unwanted polymerizations may occur in fin fans, cooling systems, or hydrocarbon and water separators. Pars Lian Company offers anti-fullet chemicals programs to control and reduce fouling in this type of equipment.