Optimizing Plant Design for Gas Monetization

By Sharada Prahladrao

Project Success Story

Customer Profile: Primus Green Energy is a gas-to-liquids (GTL) solution company located in Hillsborough, New Jersey. The vertically integrated headquarters has facilities for design, engineering, operator training and remote operation, as well as research and development, and catalyst development. The company delivers solutions for gas monetization based on its proprietary STG+ technology; this is a highly integrated process using a single loop approach, and has been optimized for many applications.

Business Challenge: Globally, approximately 140 billion cubic meters of natural gas is being flared into the atmosphere each year; the monetary value of this wasted energy is $35 billion. So, the challenge for Primus was to design a commercial plant program to monetize flared gas, stranded natural gas, and stranded ethane using innovative GTL STG+ technology.

Primus provides its clients with gas-to-liquid systems for monetizing flared gas in compliance with more stringent anti-flaring regulations and converts it into valuable liquids. Primus’ modular plants offer a profitable solution for stranded gas for remote locations, associated or flared gas at oil well pads, and stranded ethane at gas processing plants. The core technology converts natural gas into gasoline or methanol using fixed bed catalytic reactors — a tested technology using 100 percent standard components with no wastewater, gas pre-treatment or liquid post-treatment needed. The challenge was to scale up the technology to different capacities and to deliver attractive returns, for which simulation and cost estimation software were needed. Additionally, Primus also had to ensure that their modular plants are effective and profitable when compared to alternative gas monetizing options. Based on this requirement criteria, Primus began the search for the best-fit solution provider. After careful consideration, they chose AspenTech’s aspenONE Engineering Suite.

Solution Deployment: Simulation models were prepared and calibrated using the aspenONE Engineering suite, including Aspen HYSYS, Aspen Exchanger Design & Rating (EDR) and Aspen Capital Cost Estimator. These models reflect reality for different scales and the ranges of predicted feed compositions. The levels of deployment that functioned synchronously:

Pilot and demonstration level: Aspen HYSYS and Aspen EDR were used for process design, reactor system analysis and heat exchanger design and performance evaluation.

Commercial plant level: Aspen HYSYS and the economic evaluation suite were utilized for conceptual design and optimization (including process simulation for various feed gas compositions, costing for feasibility studies and scale up/scale down estimates).

When designing a new technology it makes business sense to simultaneously consider the financial angle; because not only does this result in a cost-effective solution, it requires fewer iterations and provides more time to evaluate alternatives. Moreover, Primus’ Aspen HYSYS process model is constantly validated with real data from the natural gas-to-gasoline STG+ plant.

Customer-specific Solutions:

Monetizing flared gas for a client in Central Asia: Primus boosted the liquid output from their standard plant design, enabled compliance with anti-flaring regulations, and provided a modular design suitable for that remote location.

Challenge of variations in feed gas composition: Primus used the Aspen HYSYS model to simulate the range of feed gas compositions that the modular plant could handle.

Lack of available water onsite and need for air cooling: Primus designed an air cooled system using Aspen Air Cooled Exchanger.

Primus has undertaken multiple projects worldwide and now offers not only gas-to-gasoline STG+ systems, but also gas-to-methanol STG+ systems.

Tangible Benefits: Equipped with aspenONE software, Primus can respond to client needs and deploy the best solutions depending on capacity/scale, location and compliance regulations. AspenTech’s solutions helped Primus:

  • Scale up GTL STG+ technology from a pilot plant program

  • Evaluate heat exchanger design and costing

  • Develop a program to provide customized solutions and become more energy efficient


Keywords: Primus Green Energy, AspenTech, aspenONE Engineering Suite, Aspen HYSYS, GTL, STG+ Technology, ARC Advisory Group.


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