Description

Flow measurement of natural gas feed to LNG liquefaction train

Requirements

  • High accuracy measurement of natural gas
  • Need for diagnostics to ensure measurement accuracy
  • Custody transfer measurement in case of changing ownership

Description

Natural Gas treatment for LNG liquefaction

Requirements

  • Accurate level measurement for optimal process control

Description

Treated natural gas to LNG liquefaction process

Requirements

  • Flow measurement of clean and dry gas for optimal operation
  • Continuous measurement of feed gas

Description

Flow measurement of coolant in LNG process

Requirements

  • High accuracy measurement for optimal cooling performance
  • Continuous measurement for optimal process control

Description

Flow measurement of NGL

Requirements

  • High accuracy measurement of high value product
  • Continuous measurement for optimal process control

Description

Level measurement of NGL

Requirements

  • Level measurement to prevent overfill
  • Inventory measurement

Description

Compressor seal gas measurement

Requirements

  • Prevent leakage or dry run from compressor sealing shaft

Description

Tank level point detection in LNG storage tanks

Requirements

  • Cryogenic temperatures (<-162°C)
  • Risk of overfill or dry run
  • Inventory measurement

Description

Flow measurement of cryogenic LNG to storage tank

Requirements

  • Cryogenic temperatures (<-162°C)
  • Process control

Description

Supervisory and validation software

Requirements

  • Visualisation and monitoring of critical processes
  • Control of reporting, trends and alarm handling
  • Statistical evaluation of measurement data

Description

Metering control cabinets

Requirements

  • Integration of flow computers, PLCs, supervisory computers and printers
  • Installation of single flow computers up to fully redundant cabinet

Overview

Drying, filtering and liquefaction in the oil & gas industry

Quality and composition based measurement of liquefaction

After well-head processing, natural gas is collected and typically delivered to the liquefaction plant by pipeline. The delivered quantity is measured in a custody transfer metering skid, and analyzer instrumentation determines the composition and quality. Before the main liquefaction processes, various filters and scrubbers complete the drying, and remove impurities such as mercury, H2S and CO2.

The major component of LNG is methane, which liquefies at -162°C. Cooling is achieved in one or more liquefaction trains. In this process, various constituents found in natural gas (propane, ethane, and methane) are typically used as refrigerants, either individually or as a mixture. During the cooling processes, ethane, propane and butane are extracted at various stages, as ‘natural gas liquids’ (NGLs), and are measured and recovered as by-products.

Once liquefied, the LNG product is stored in large, well insulated tanks, awaiting onward transport. These tanks are fitted with cryogenic level switches to control high and low levels, but the LNG is not actively cooled - so the liquefied gas inside the tank boils. The boil off gas (BOG) is returned to the liquefaction train, where it can be re-processed.

KROHNE supplies the custody transfer metering systems for natural gas entering the LNG plant, and for the cryogenic LNG product, as well as other cryogenic measurement instrumentation for use on the plant. Amadas (analyzer management) software systems from KROHNE guarantee the performance of the analyzers used to determine the quality of the natural gas and LNG. KROHNE ultrasonic and Coriolis mass flowmeters are suitable for all LNG production or distribution measurement solutions.

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