Petrochemical processes often involve high temperatures, high pressures, and fluids with corrosive or hazardous characteristics. Heat exchangers used in these systems require reliable performance under demanding operating conditions while maintaining efficient heat transfer. Gasketed plate heat exchangers are commonly used in petrochemical auxiliary systems, such as cooling water circulation and low-pressure heating applications. However, their operating limits are affected by the temperature and pressure resistance of the gasket materials. Plate & shell heat exchangers combine the high heat transfer efficiency of plate structures with the pressure resistance of shell-type designs. The corrugated plates are laser welded into a sealed plate pack and enclosed inside a pressure-resistant shell. Without traditional rubber gaskets, the structure supports higher temperature and pressure conditions compared with conventional gasketed plate heat exchangers. At the same time, the internal plate design maintains efficient heat transfer performance and a more compact structure compared with traditional shell and tube heat exchangers, which makes plate & shell heat exchangers suitable for demanding petrochemical processes.