Blue Sphere recently completed an interesting project for a large tanker cleaning operation in Houston TX. This facility maintains seven steam heated tanks which contain cleaning solutions. These tanks are referred to in the tanker cleaning industry as “Vats”. The cleaning solutions are circulated inside of the tankers using moderate flow and pressure pumps (~150gpm@150psi typical) and applied through gear driven, spinning nozzles referred to as “Spinners”. These vats are commonly heated to an operational temperature of 180F due to the increased solubility and improved cleaning action of the fluid at higher temperature.
The goal of the project was to install highly accurate modulating valves and related controls to maintain a constant temperature in each of the vats. The economic motivating factor was cost. The facility maintains a 200HP fire tube package boiler and was incurring natural gas bills in excess of $13,000 per month. This natural gas usage is in excess of the national average for a similar facility. Mangers recognized that overheating of the vats due to inoperable and inaccurate temperature control was a major source of energy wastage.
The facility selected a high end temperature control solution. Modulating valves which accept a 3-15psi air signal based off of temperature feed back from RTDs were installed in each vat. Blue Sphere designed and built a customized control panel including seven stand alone PID controllers and I2P transducers. The control panel interpreted the temperature feedback from each vat and produced a corresponding 3-15psi output to the steam valve on each vat. Using a PID loop, the steam valves apply only as much steam to the vat as is necessary to maintain the target temperature. This solution has effectively eliminated steam wastage at the facility. Steam control systems are available from Blue Sphere Water Technology.