Measuring moisture in pipeline natural gas with Panametrics
Natural gas is distributed through a network of pipelines and stored in tanks, underground caverns and spent oil wells. The presence of excess moisture in natural gas results liquid water condensing or ice formation in cold climates or when gas is decompressed due to Joule-Thompson cooling. Excess moisture combined with high pressure leads to the formation of solid hydrates. Ice and/or hydrate formation can restrict or even block the flow in the pipeline. The moisture content of the gas adversely affects the heating value (BTU) of the gas, thus lowering the quality and value of the product. Water also combines with “acid” gases such as Carbon Dioxide and Hydrogen Sulfide and accelerates corrosion. In order to meet gas quality requirements and protect the pipeline and storage infrastructure the moisture content must be continuously monitored.
The distribution of natural gas must comply to specifications for the maximum moisture concentration referred to as the “tariff”. In the United Sates the tariff is 7lbs/mmscf (pounds per million standard cubic feet) and in Europe the maximum recommended level is -8°C dew point at 70 Bar(a). Other countries and localities have similar specifications for the maximum amount of water in natural gas. Suppliers who exceed the maximum levels may be “shut in” for non compliance. A shut in is a loss of revenue for gas suppliers.
Early detection of an increase in the moisture content allows the operator to determine the root cause of the problem prior to catastrophic blockage, leaks due to corrosion or loss of revenue due to a shut-in at a custody transfer point. Most gas distribution and compression facilities are challenged with fewer operation and maintenance personnel and higher reliance on automated data acquisition and control systems. This means that that the instruments must be low
Benefits: • Multiple moisture measurement technologies • Systems designed to meet your budget • Complete turnkey systems. Just connect power, gas sample and output signal • No onsite calibration required
"Installing Panametrics time proven Aluminum Oxide (AlOx) trace moisture sensor offers great value. HygroPro Transmitters provide direct display and a 4-20mA signal for lbs/mmscf, dew point temperature ppmv (parts per million by volume). For natural gas applications the HygroPro is installed in a sample system, designed to filter, regulate and indicate the flow and optionally control the temperature.
The Moisture.IQ is a multifunction and multichannel analyzer which connects to (6) AlOx trace moisture probes, (6) Oxygen sensors and (12) analog inputs. The unit is programmed via a color touch screen or remotely via ethernet (TCP/IP). It provides digital and analog outputs and is equipped with an internal data logger. The Moisture.IQ has built in intrinsic safety barriers enabling connection to sensors in hazardous areas. These instruments are ideal for facilities with multiple measurement points or where redundant measurement is required. It is available in bench top/rack mount, wall mounted weatherproof and in an explosion proof enclosure.
The PM880 is a portable battery-operated intrinsically safe analyzer which is ideal for spot checking and data logging. It can be used to verify the moisture content at various locations in pipeline infrastructure.
The Aurora TDLAS (Tunable Laser Absorption Spectrometer) moisture analyzer provides definitive moisture measurement by using a fully non-contact technique. The cost of installing an Aurora provides “return on investment” because there is no need for field calibration or sending sensors out for recalibration. Aurora are the fastest responding trace moisture technology therefore if there is a malfunction in the dehydration system, once corrected, confirmation of dry gas is assured. The Aurora provides a local display, 4-20mA signals, RS232/485, and Ethernet with MODBUS. The Aurora-Transport is battery operated and assembled in a high impact luggage case.
• USA: 0-25 lbs/mmscf (0-525 ppmv) with Alarm at 7lbs/mmcf • Europe: -40 to 0°C Dew Point at 70 Bar(a) with Alarm at -8°C Dew Point • Options for display of moisture in lbs/mmscf, dew point temperature or ppmv • 4-20mA signal Local display • Options for weather proof and heated enclosures • Options for sample conditioning systems • Certification for hazardous area operation: Explosion proof and intrinsically safe
Learn more about our tunable diode laser absorption spectroscopy (TDLAS) hygrometers