Specialists in Refinery Turnaround
Cesco offers a wide range of refinery turnaround chemical cleaning support services. Experienced chemists, chemical engineers and technicians assist in the planning and implementation of vessel decontamination efforts. Chemical cleaning eliminates worker exposure to dangerous atmospheres containing explosive gases, H2S and Benzene upon vessel entry.
Three general treatment schemes cover most decontamination efforts:
1) Vapor Phase
Vapor phase cleaning works well in small vessels with packed beds, isolated exchangers and pipelines. Chemical cleaning agents are introduced into a steam line during routine steam-out procedure after equipment has been pumped out, drained, vented and blinded. Chemicals are entrained in the vapor where they contact all surfaces. The hydrocarbons are stripped from the vessel and end up in the condensate. This process generates low volumes of wastewater.
2) Overhead Cascade
Overhead cascade cleaning works well for towers that have trays with good liquid flow distribution. Chemicals are introduced into a water/steam manifold and pushed up the reflux line into the top of a tower. Stripping steam is introduced into the tower as per normal steam out to add heat and agitation. The hot chemical mixture cascades down through the trays and is sent to the sewer through the bottom drain.
3) Fill and Percolate
Horizontal vessels and vessels with de-misters and packing are often best treated with a combination of vapor phase and fill and percolate procedures. Vessels are first steamed out with chemicals and then filled and percolated with steam and nitrogen to agitate.