Optimization of the ABB Randall process of NGL recovery

In the simulated ABB Randall Process before optimisation, it was found that the process initially achieved a yield of 72%, indicating the potential for further improvement and optimization. Replacing J-T valves with an expander, led to a remarkable drop in the DeMethanizer inlet temperature, from -150°C to -274°C, resulting in more efficient recovery of heavier hydrocarbons. This lower temperature was attained through isentropic expansion, with the expander's work driving a compressor to enhance overall plant efficiency. A comparative analysis between the unmodified ABB Randall process and the optimized version demonstrated the clear advantages of the latter. The optimized process exhibited higher annual revenue, increased annual savings, a shorter payback period, reduced energy costs, and a substantial improvement in natural gas liquids (NGL) recovery, with a recovery rate of 96.4%. While the initial capital cost investment for the optimized process was slightly higher, the accrued financial and operational benefits make it a more attractive and cost-effective choice in the long run.