Optimization of multistage membrane distillation system for treating shale gas produced water

Abstract

Thermal membrane distillation (MD) is an emerging technology to desalinate highsalinity wastewaters, including shale gas produced water to reduce the corresponding water footprint of fracturing operations. In this work, we introduce a rigorous optimization model with energy recovery for the synthesis of multistage direct contact membrane distillation (DCMD) system. The mathematical model (implemented in GAMS software) is formulated via generalized disjunctive programming (GDP) and mixed-integer nonlinear programming (MINLP). To maximize the total amount of water recovered, the outflow brine is fixed close to salt saturation conditions (300 g·kg -1 water) approaching zero liquid discharge (ZLD).A sensitivity analysis is performed to evaluate the system's behavior under different uncertainty sources such as the heat source availability and inlet salinity conditions. The results emphasize the applicability of this promising technology, especially with low steam cost or waste heat, and reveal variable costs and system configurations depending on inlet conditions. For a produced water salinity ranging from 150 g·kg -1 water to 250 g·kg -1 water based on Marcellus play, an optimal treating cost are between 11.5 and 4.4 US$ m -3 is obtained when using low-cost steam. This cost can decrease to 2.8 US$ m -3 when waste heat from shale gas operations is used.

Environmental and Economic Water Management in Shale Gas Extraction

“…On the other hand, in order to evaluate the whole sustainability of the process, it is also interesting to compare the results obtained in our environmental study with other factors, such as the cost of each technology. In this sense, a comparison between the total impact and the cost of all the technologies (based on the works by Carrero-Parreño et al [51] and Onishi et al [50]) is shown in Figure 5. The multiple-effect evaporation (MEE-MVR) system is around 35% less expensive than the SEE-MVR system, as was shown in the publication by Onishi et al [50].…”

“…Another important aspect to consider is the amount of water recovered by each technology. In this way, a high rate of recovery should be obtained with the optimal configuration, while the brine removal should be near the zero-liquid discharge (ZLD) strategy [50,51]. Thermal desalination technologies allow recovering approximately 76.7% of water (regarding the inlet flow), while membrane distillation allows recovering approximately 33.5% of water.…”

“…In this work, we have also considered a membrane-based technology from the work by Carrero-Parreño et al [51], where an optimization model for the optimal design of a multistage membrane distillation system is presented to recover treated water and brine near to the Zero-Liquid Discharge (ZLD) condition. An optimal membrane configuration including 3 stages is considered.…”

Review of Transport Phenomena and Popular Modelling Approaches in Membrane Distillation

“…In comparison with other MD configurations, DCMD has the highest proportion of heat conduction loss through the membrane. Furthermore, since the vapour condenses directly into the permeate stream, it is not easy to recover the latent heat from the permeate stream by a multistage design, which has limited gained output ratio (can also be defined by Equation (16)) to less than 1 [ 70 , 71 ].…”

Energy Management Optimization of Open-Pit Mine Solar Photothermal-Photoelectric Membrane Distillation Using a Support Vector Machine and a Non-Dominated Genetic Algorithm

“…Case studies show that WPC can be reduced by 38.1% [20]. An air gap membrane distillation module with energy recovery can be used for desalination experiments and the system can be optimized using response surface methodology [21]. The parameters of cold feed inlet temperature (T1), hot feed inlet temperature (T3) and feed flow rate (F) are considered, and the membrane flux (J) and thermal efficiency (GOR) are the targets [22].…”