Monday, 15 August 2011
Reproduced from an Inside Knowledge article here which quotes an internal story from Fluor corporation , this
"I worked on a process study in Kuwait for dehazing of diesel and gas oil to meet the Haze-2 specification at 77°C. Roughly said, this meant reducing the water content from 1000 parts per million by volume (ppmv) at 135°F [Fahrenheit] to 100 ppmv at 77°C. The client-design basis was to use an electrostatic coalescer and salt-bed drier with a water cooled chiller, to pre-cool the coalescer feed to 105°F.
On Knowledge OnLine, we found the salt-bed drier manual. This manual provided valuable information. Among other things, it recommended maintaining an operating temperature in the salt-bed drier at or below 100°F to restrict brine solubility in diesel.
Via the Process Community forum we asked for designing and operating experience with the proposed electrostatic coalescer/salt-bed drier design, the effect of operating temperature on the degree of drying, experience with alternative drying processes and advice on the most economical design solution for the given capacity: coalescer/salt bed drier or vacuum drying.
Within three days, three responses where received, from Haarlem [Netherlands] and the Calgary [Canada] offices. They provided project references/contacts for each of the different design options considered. The information underlined the strong effect of operating temperature on salt-bed efficiency: at too high an operating temperature the efficiency of the salt bed is eliminated by the brine solubility in diesel. This insight was confirmed by vendor information: “The dynamics of the salt bed is such that it is only 30-35 per cent efficient and at higher temperature the water simply partitions back into the diesel stream.”
Based on this information and project references, our recommendations to the client were to pre-cool the diesel/GO feed to 60°F with a chiller before being sent to the coalescer and to eliminate the salt-bed drier. The Fluor recommendation was recognised by the client as a positive improvement. Knowledge OnLine allowed the client to make an informed decision in favour of the new concept for the Dehazing Facility design.
Based on the information from Knowledge OnLine, the client asked to visit one of the project references mentioned: an existing refinery. This visit was arranged through the Haarlem office and is now planned for next month.
Value for the client: The elimination of the salt-bed drier saved the client money on equipment cost (TIC reduced by >1m) and operational cost. In addition, elimination of the salt bed drier will save a lot of maintenance hassle in future.
Value for Fluor: Client satisfaction: The client is positive about the alternative design solution proposed by the Fluor team. They were impressed by the short response time, the quick access of our team to Fluor’s worldwide knowledge and expertise and the new possibilities it opened (for example, the client visit to an operating facility). Our client is so pleased that a new work-order has been awarded to Fluor: a similar study for the other refinery of the client. This study represents a business value of 700,000. Once the feed package is approved, to carry out the job would even fetch a much higher value for Fluor".