2.6 Conclusions
A methodology was developed for process design under uncertainty for a shale gas treatment plant. An integrated approach of process simulation, design under uncertainty, techno‐economic analysis, and safety assessment was used to determine the optimal design of the gas treatment plant. A number of feeds with varying inlet compositions were examined to represent the uncertain compositions of shale gas. A case study was carried out for data from the Barnett Shale Play.
A key observation is the increase of both revenue and processing costs with increasing NGL content. As measured by ROI, all feeds (including the high acid case) are worth treating, except the high methane case (Feed #1). From the sensitivity analysis, it can be concluded that for the base case, shale gas processing is still profitable for even the highest feedstock prices. However, a drop of one standard deviation in product prices will make processing highly unprofitable.
Appendices
Included in the Appendix are key parameters for the process simulations. Further guidance can be found in the Bryan Research & Engineering guide [24].
Appendix A: Key Parameters for the Dehydration Process
2.A
Table 2.A.1 Dehydration column parameters for the base case (Feed #3).
| Column | Feed flow rate (MMSCFD) | T (°F) | P (psig) | Number of trays |
| Contactor | 150 | 101 | 996–998 | 2 |
| Regenerator | 0.830 | 214–308 | 0–4 | 4 |
Feed flow rate is a standard vapor volumetric flow rate.
Table 2.A.2 Makeup composition for the base case (Feed #3).
| Stream | Water (mass%) | TEG (mass%) |
| Makeup | 0.1 | 99.9 |
Table 2.A.3 Glycol circulation rate for the base case (Feed #3).
| Stream | Circulation rate (gal/lb) |
| 21 | 2–5 gal glycol/lb water in stream 1 |
Appendix B: Key Parameters for the Turboexpander Process
2.B
Table 2.B.1 Demethanizer column parameters.
| Column | Total feed flow rate (MMSCFD) | T (°F) | P (psig) | Number of trays | Light/heavy key |
| Demethanizer | 202 | −111 to 65.4 | 250–254 | 10 | Methane/ethane |
Feed flow rate is a standard vapor volumetric flow rate.
Table 2.B.2 Low temperature separator (LTS) inlet temperature.
| Stream | T (°F) |
| 10 | −25 |
Table 2.B.3 Outlet pressure for the pressure changing equipment.
| Stream | P (psig) |
| 13 | 250 |
| 14 | 255 |
| 21 Residue gas | 900 |
Appendix C: Key Parameters for the Fractionation Train
2.C
Table 2.C.1 Fractionation train column parameters for the base case (Feed #3).
| Column | Feed flow rate (MMSCFD) | T (°F) | P (psig) | Number of trays | Light/heavy key |
| Deethanizer | 27.1 | 38.8–159 | 285–292 | 35 | Ethane/propane |
| Depropanizer | 17.9 | 104–187 | 190–193 | 36 | Propane/i‐butane |
| Debutanizer | 8.09 | 163–219 | 135–140 | 60 | n‐Butane/pentane |
| C4 splitter | 5.74 | 147–179 | 120–140 | 60 | i‐Butane/n‐butane |
Feed flow rate is a standard vapor volumetric flow rate.
Appendix D: Key Parameters for the Acid Gas Removal System
2.D
Table 2.D.1 Acid gas removal column parameters.
| Column | Feed flow rate (MMSCFD) | T (°F) | P (psig) | Number of trays |
| Contactor | 150 | 100–110 | 796–800 | 7 |
| Regenerator | 150.18 | 210 | 8–12 |
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