REAL TIME MONITORING OF PIG TRAVEL
Throughout the job, pigg travel and pipe cleaning are continuously monitored. The hydraulic driving pressure and flow rate values versus time are recorded. The resulting pressure profile measures the resistance to pigg travel, enabling the operator to determine the location of fouled sections and the extent of the deposit build-up.
The information obtained from each cleaning run is used to select a subsequent pigg size, the appendage type and appendage height. The recorded plot of the pigg driving pressure clearly delineates the pipe condition and pigg travel. The water returning from the heater coils is closely observed for a diminished or nonexistent slurry return. Clean return water and a smooth and consistent trace on the chart recorder signifies that the progressive pigging program is completed.
A final pressure profile is obtained and recorded, and compared with the initial pressure profile. This information is available to the operator and on-site engineering staff for confirmation that all deposits have been completely removed.
Click to enlarge.