Dew Point Control
DPC™ was founded in early 2003 with the idea that it would lease JT and refrigeration units to the local producers needing to meet the 45°F HDP (Hydrocarbon Dew Point) pipeline specifications that were prevalent in the East Texas region. The conditioning units employ a simple two phase separator to remove the condensed cold liquids from the lighter volatile gaseous hydrocarbons (sales gas). In a typical application, the cold liquids flow to the producer's low pressure crude separator (60 to 100 psig) at which point additional light volatile hydrocarbons are flashed off and recovered by low pressure compression. The remaining NGL's mix with the field produced crude or condensate for sale. For applications that attain the desired sales gas specification with cold separators operating at temperature greater than 30°F, this is still the most common method of handling the NGLs and generates the highest market value for the product. DPC's installations began to be installed on systems requiring lower HDP specifications. In conditioning units with cold separator temperatures operating below 30°F, the amount of light volatile hydrocarbons held by the cold separator liquids increases dramatically. This requires the recovered NGL's to be stored in pressurized tankage. The cold liquids are typically flashed directly from the cold separator into a pressurized storage tank. The storage tank has a back pressure regulator controlling the pressure of the vapor space to maintain a pressure in the 100 psig to 175 psig range which allows the most volatile hydrocarbons to weather off from the liquids. The flash gas vented from the pressurized storage vapor space is either consumed as fuel or recompressed as a recycle stream back to the front of the conditioning unit. The pressurized NGLs are marketed as a mixed NGL product with 2% to 6% methane content.
There is a need by some of our clients for further liquid stabilization of the produced hydrocarbon liquids beyond the simple single flash stabilization technique. Additionally, the pressurized NGL storage is becoming increasingly subject to Federal regulation under OSHA's PSM (Process Safety Management) program and the RMP (Risk Management Plan) requirements. The associated pressurized truck loading is also an operation with exposures of both personnel safety and air emissions. In some instances, it has become increasingly difficult for our clients to find local sales outlets for these pressurized liquids, and in some locations to schedule pressurized transport trucks in a timely manner.