Modularised plants in action
Some of the real life applications seen across the US shale basins in the last few years showcase the unique challenges customers face. For example, flat topography in the Eagle Ford might be replaced by more mountainous terrain in the Marcellus. High altitude areas such as the San Juan Basin can be contrasted with lower lying areas in Louisiana. Some areas produce lean gas with low to moderate levels of NGL, and some areas have high levels of NGL that demand more recovery with associated equipment.
Case study one
In the Marcellus Shale Basin, an operator acquired a 120 000 ft3/d cryogenic unit with a refrigeration package to process natural gas containing 6 - 7 gal./min. After startup, the customer determined that they had higher gas rates than anticipated. The equipment supplier worked with the customer to find a solution, designing a flexible system that would meet their gas specifications. The customer was then able to push gas volume throughput to 115% of design and process 138 000 ft3/d. This enabled the client to secure more gas contracts.
Since the installation of the first plant, the site has increased from 138 000 ft3/d capacity to 660 000 ft3/d by adding two, 200 000 ft3/d cryogenic units with refrigeration and a 120 000 ft3/d cryogenic unit with refrigeration. Because of this, the customer was able to break ground in a green field site and then expand into a major gas processing hub for the Marcellus area. The customer has returned to modular solutions for additional gas processing needs.
Case study two
In the Eagle Ford Shale, an operator was aware that he had to process up to 600 000 ft3/d of gas within a two year timeframe. The operator partnered with the equipment supplier to make certain that they could achieve this without consuming the time it would take to construct a stick built plant. Adopting a modular approach saved time in project timeline execution and made rapid NGL extraction a reality.
The first 200 000 ft3/d cryogenic plant installation was finalised in the third quarter of 2012. The second 200 000 ft3/d cryogenic installation was finalised in the first quarter of 2013, and the final cryogenic 200 000 ft3/d installation will be finalised in the first quarter of 2014. One benefit of this schedule was that equipment was installed as gas demand ramped up, which only a modular approach can do. Another benefit was that the operator had three identical plants with the same list of common spare parts. This signifies a greater maintenance familiarity as more plants came on line. The operator could then purchase common compression for each train, leading to a more homogenous operation.
Rapid project deployment for optimum economic returns
When delivered by an experienced solution provider, solutions for CO2 removal, dewpointing and NGL recovery can be delivered as prefabricated, skid mounted modules that provide feed composition flexibility and rapid NGL recovery. This lowers fabrication costs, speeds installation and provides high onstream efficiency. Modular, prefabricated solutions enable economic development of shale gas resources that would otherwise pose as daunting processing challenges given their inherent variability in gas composition. Operators using this modular approach truly benefit through more efficient operations and optimal monetisation.
Written by Mark Schott and Neil Eckersley, UOP LLC, A Honeywell Company, and edited by Emma McAleavey.
The full article can be found in the May issue of Hydrocarbon Engineering.
Read the article online at: https://www.hydrocarbonengineering.com/gas-processing/29042014/keep_up_the_pace_431/