US Patent 11174439 Method to inhibit polymerization in a process water

Disclosed herein are methods for reducing fouling caused by process water present within a water recycling loop of a pyrolysis plant. Fouling is caused by phase separation and accumulation of materials from the process water on equipment surfaces. The method includes applying a total of about 5 ppm to 500 ppm total of a first polymerization inhibitor and second polymerization inhibitor to the process water to form a treated process water, wherein the first polymerization inhibitor has a pygas-water partition coefficient of about 0.0001 to 9 and the second polymerization inhibitor has a pygas-water partition coefficient of about 1000 to 50,000.