(162a) Optimizing Water Jetting Cleaning of Heat Exchangers

Cleaning of industrial equipment is a crucial activity that provides significant operational and economic savings. More specifically, the periodic cleaning aimed at the removal of fouling deposits in heat exchangers enables energy savings, debottlenecks production and contributes to reducing the carbon emission of industrial facilities. Cleaning of heat exchangers can be performed using a variety of methods (e.g. Mechanical, Chemical, Thermal, etc.) that can be selected depending on a number of factor such as equipment type, process fluids and conditions, fouling characteristic etc. Among the various options, Mechanical cleaning accounts for about 80% of cleaning actions performed in refinery and petrochemical plants, with hydro-blasting being the most popular amongst the mechanical cleaning methods. Hydro-blasting relies on high-pressure water jets that mechanically detach fouling deposits from the equipment, thus is often referred to as water jetting. The performance of this cleaning method mainly depends on the outlet pressure (pressure loss), stand-off distance, nozzle diameter, fouling deposit characteristics and pumping power. These variables directly affect the energy consumption (and related cost) of the cleaning process and its optimal value is of great importance for all cleaning technology providers. This work proposes an optimisation-based approach to find optimal operating conditions (namely flow rate, nozzle diameter, stand-off distance, fouling deposit properties and pumping power) that minimises pressure losses in the cleaning equipment, together with water consumption, fuel usage and related CO₂ emissions). This study provides a potential method for predicting the effectiveness of water jetting actions and achieving optimal cleaning performance with minimum energy consumption.