Inlet Moisture Considerations | Startup Assistance & Field Service | Pressure Storage & Facilities Design & Procurement Statement

Startup Assistance and Field Service:

Standard DPC field service included in the rental rate includes up to two days initial onsite startup assistance, quarterly jobsite visits/consultations, and telephone and email support for troubleshooting and assistance. Additional onsite service is available on a Time and Material reimbursement basis. In addition, our Instrument/Electrical contractor is available for any onsite work, on our equipment or other, on a case-by-case basis negotiated and priced directly with the contractor.

  1. Operator Maintenance Responsibilities

    • Lessee is expected to maintain the unit properly, including safeguarding the inlet from various contaminants that will materially interfere with the proper operation of the equipment. Lessee is required to properly clean the unit at the end of the lease prior to returning it to the DPC yard, otherwise a cleaning fee will be imposed. As part of the DPC field service, DPC will coordinate with lessee to inspect the unit prior to leaving the lease; this should alleviate any additional cleaning fees. It is especially important for both safety and regualatory reasons, that ALL liquid hydrocarbons be blown down and removed from the units prior to loading on truck transport.
    • DPC shall transfer to Lessee any warranties made to DPC by the manufacturer or supplier. Specifically, instrumentation items and chemical injection pumps will be repaired and maintained during the initial 30 day operating period, while the remaining equipment and piping will be repaired or rebuilt by DPC during the entire term of the lease. Normal and routine equipment and instrument maintenance, such as cleaning, and clearing of debris from valves or other equipment, or tightening of flange, threaded joint, or packing gland or stuffing box leaks, will be the responsibility of the Lessee.
    • In general, DPC expects that the Lessee will operate, troubleshoot, and maintain the process skids, or any other equipment, besides the chilled water packages, as if they were their own.

  2. Operational Issues and Troubleshooting
    Sales Gas Dew Point or Unit Freeze-up Problems:

    • The biggest operational issue that DPC encounters with the operation of JT units is the fluctuation of the sale pipeline operating pressures. The DPC JT unit is instrumented to hold a constant pressure upstream of the unit. When the sales pipeline varies in pressure, this changes the differential pressure across the JT value, which causes wide variations in the process temperatures. The hydrocarbon dew point at the operating pressure of the unit is the temperature of the cold separator. Fluctuating temperatures will cause fluctuating dew point temperatures. When the process temperature gets too cold, the unit can freeze or hydrate. The simplest and most reliable fix for varying pipeline pressure is to install a backpressure controller and valve downstream of the unit. Set this controller at approximately 30 psig above the highest-pressure swing expected on the pipeline. This will stabilize both the pressure drop across the JT valve the unit operating temperature.
    • The JT skid hot gas bypass valve (the one that has a manual regulator) can also be automated with a KimRay T-12 temperature controller. This gas bypass can control temperatures over a range of approximately 15 degrees. A thermowell is provided on the unit, on the exchanger nozzle feeding gas to the separator, to permit field installation of the temperature controller.
    • The manual hot gas bypass is used when icing or hydrate problems are suspected. Opening the bypass will warm up the unit approximately 15 degrees. This is an easy solution that does not affect any instrument settings or operating pressures.