Styrene waste gas recovery in resin industry requires anti polymerization design

Styrene waste gas recovery in resin industry requires anti polymerization design

In the process of resin production, styrene is often used as diluent and crosslinking agent, especially in the production of unsaturated polyester resin, styrene thermoplastic elastomer and other products. Styrene has a boiling point of 146 degrees Celsius, which is a high boiling point volatile organic compound, but at the same time it has the characteristics of easy polymerization. When heated or in contact with the active surface, it is prone to self polymerization reaction, generating viscous polystyrene, which brings special challenges to waste gas recovery.

Styrenewaste gas treatmentThe main difficulty lies in the aggregation risk. When styrene gas passes throughactivated charcoalIn the case of adsorption materials with active surfaces such as molecular sieves, polymerization reactions will occur on the surface of the materials, which will block the pores and lead to the deactivation of the adsorbent. Under high temperature conditions, the polymerization reaction is accelerated. Therefore, styrene waste gas is not suitable for activated carbon adsorption or high temperature combustion process. The membrane condensation recovery process is specially designed for the characteristics of styrene, and the core idea is to add anti-polymerization measures for low-temperature operation.

In the process, the styrene waste gas first enters the condensation unit, and the temperature quickly drops to minus five to minus ten degrees Celsius. Styrene is liquefied from a gaseous state to a liquid state at conditions well below its boiling point and is recovered from the bottom of the plant. Since the low temperature environment effectively inhibits the occurrence of polymerization reaction, styrene will not polymerize and scale in the condenser. The condensed tail gas passes throughgas separation membraneThe residual styrene is recycled back to the condensation inlet for further treatment after enrichment. The membrane material is polydimethylsiloxane rubber membrane with very few surface active groups, which will not catalyze the polymerization of styrene.

In the equipment design, take a number of anti-polymerization measures. The condenser adopts a smooth heat exchange surface to reduce the residence time of styrene adhesion. The internal pipes and valves of the equipment are made of stainless steel, and the inner wall is polished to reduce the roughness. The system is provided with a nitrogen purge interface to replace the residual styrene in the system with nitrogen during shutdown to prevent polymerization during shutdown. For high-concentration styrene waste gas, a polymerization inhibitor injection device can be added before the condensation unit, and micro-injection can further inhibit polymerization.

In practical application, the use of membrane condensation recovery process to treat resin production of styrene waste gas, the recovery rate can reach more than 95%, the recovery of styrene purity of more than 90%, can be directly reused in production. The emission concentration meets the environmental protection standard, the equipment runs stably, and there is no problem of polymerization blockage.

LuoyangWohong PetrochemicalEquipment Co., Ltd. provides membrane condensation solutions for anti-polymerization design for styrene waste gas recovery. The company is located at W2-1, Dongda Science and Technology Industrial Park, Luoxin Industrial Cluster Zone, Xin’an County, Luoyang City. Website: www.wohongshihua.com.