Issue link: https://geospatial.trimble.com/en/resources/i/1415432
Speed The third meaningful operating benefit associated with the use of an RVRU is the speed of the operation. Proper use of an RVRU can cut tank degassing time in half when compared to the largest available skid mounted combustion units. This means faster tank turnaround times. A case study of the Purgit RVRU here shows a significant decrease in the time required to degas a gasoline storage tank on the Gulf Coast. Case study Purgit was paired with a local hydroblast company to clean a gasoline storage tank next to a process unit at a Louisiana refinery. Purgit was engaged to bring the concentration of the product vapour inside the tank down below the lower explosive limit (LEL) (degas the tank) using a RVRU. Purgit began to condense and recover the gasoline vapour before the hydroblast company began to wash the remaining product off the floor using a man-way cannon. The wash water was periodically pumped into a vacuum truck while the RVRU condensed and pumped the recovered hydrocarbons to totes. After 12 hrs of run time, multiple meter readings of 35% LEL were recorded. A total of 505 gal. of liquid gasoline was recovered from the vapour alone by the RVRU and pumped into totes. This work was accomplished without any tank emissions and without a flame in the refinery. Furthermore, both the customers and Louisiana Department of Environmental Quality (LADEQ) specifications were met before disconnecting. Plastics production Finally, there are applications that do not allow for combustion as a vapour treatment option. Chlorinated solvents are used heavily in plastics production. These compounds break down, in part, to hydrochloric acid (HCl) when sent to a combustion system. The RVRU allows these solvents (ethylene dichloride [EDC], chloroform, trichlorethylene [TCE], perchloroethylene [PCE], and others) to be condensed and recovered in short order and at a minimal cost when clearing a storage tank for maintenance or inspection. Tank terminals storing these products have few, and time-consuming options for vapour degassing. Refrigeration vapour recovery brings their maintenance costs back in line with more easily flared cargos, which can be passed along to the customer. Conclusions In conclusion, portable refrigerated vapour recovery can be safer, cleaner, faster, and at the same cost or cheaper than the most common combustion systems currently available for vapour control work. Efficient and clean RVRUs may be an important tool missing from a terminal's operation.