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AbstractMembrane Technology and Research, Inc. has proposed a hybrid system combining amine scrubbing with membrane technology to reduce energy cost. Previous studies of CO2 absorption mainly focused on coal-fired flue gas with 12% CO2. However, in the hybrid process, the CO2 in the flue gas can be enriched to 20%. Natural gas turbines will have flue gas with as little as 3% CO2。 Based on the arrangement, the hybrid amine/membrane system provides a gas to the system that has double the CO2 concentration of normal flue gas, reduces the volume of gas sent to the capture unit, or reduces the removal requirements for the capture unit.The objective of this work is to minimize the total energy use of stripping concentrated piperazine (PZ) at rich loading when treating flue gas from 3 to 20% inlet CO2. The base-case stripping configuration is the advanced flash stripper with warm rich bypass and cold rich exchanger bypass. . This configuration includes two split cross-exchangers in series, a convective steam heater, a smaller stripper column, a low residence time flash tank, and stripping at high temperature to produce CO2 at 5 to 17bar. Rich loading in 5 and 8m PZ was varied from 0.37 to 0.43mol CO2/mol N. For each rich loading, lean loading was optimized to minimize the total equivalent work. The “Independence” model for PZ in Aspen Plus® was used to simulate the stripping performance.Because 5m PZ has a lower viscosity than 8m PZ, it can achieve a reduced approach temperature in the cross exchanger. The total energy performance for 5m PZ is practically the same as 8m PZ, even though the capacity of 5m PZ is lower. Significantly more energy is required to regenerate solvents with lower rich loading. As CO2 rich loading increases, the equivalent work requirement decreases for the same loading difference between rich and lean.Stripping data for 24 cases, including heat duty, equivalent work, CO2 output pressure, and optimal cold and warm rich bypass were used to build a correlation with CO2 rich and lean loading. The Second Law efficiency based on the ratio of stripping minimum work and total ideal work was introduced to make the most of stripping work. The Second Law efficiency has a maximum value at a specific CO2 loading.

AbstractSwitchable exhaust air (SEA) window allows the exhaust air from HVAC system to be ventilated through the cavity of the window to ambient. It can be regarded as an exhaust air heat recovery device in buildings. The annual energy requirement of the window has been calculated in Wuhan, China. The energy requirements for conditioning fresh air with and without the total heat recovery ventilators (THRVs) are also investigated. Heat recovery performance of the SEA window and the THRVs is compared. Results show that the SEA window can potentially provide alternative solution for recovering the low-grade energy from air-conditioning exhaust air.

AbstractBio-syngas from gasification of sugarcane bagasse is one of the most promising sources for renewable energy. As an agriculture-based biomass, sugarcane bagasse has a high content of moisture (46-52%), fibrous (43-52%) and low bulk density (80-120kg/m3). This quality of bagasse will tend to initiate agglomeration and cause de-fluidization. It will disturb the gasification process and finally will decrease yield and quality of syn-gas. Its chracteristics in low quality can be improved by pretreatment, i.e., torrefaction process, addressed by slow heating of biomass on wet or dry conditions on atmosphere pressure for 1hour before it is used as feedstock gasification.This preliminary work features an experimental investigation of torrefaction process of Indonesian sugarcane cane bagasse. Temperature of torrefaction varies from 150, 175, 200, 225, 250 and 300°C. For bagasse gasification process, the optimum temperature of dry torrefaction is 150°C. At this temperature, yield of syngas will higher than other torrefaction temperature. Temperature of dry torrefaction will give energy saving opportunities than that's of wet torrefaction (180°C, 1 hr).Analysis ultimate and proximate also indicate that sugarcane bagasse with temperature torrefaction 150°C give better result than other torrefaction's temperature in high content of hydrogen and low content of carbon.

AbstractPrincipal Component Analysis (PCA) was used to evaluate groundwater quality data acquired in the pre-injection and injection periods for the Illinois Basin – Decatur Project (IBDP), a large-scale carbon capture and storage (CCS) project located in Decatur, Illinois, USA. For the pre-injection and injection periods three principal components explained 76.6% and 80.0% of the total data variance, respectively. Analysis of the pre-injection data set determined that highly positive loadings for total dissolved solids, chloride, bromide, sodium, magnesium, potassium, and electrical conductance designated the first component (PC1) as the salinity factor. High loadings for calcium, iron, and sulfate in component two (PC2) represents an oxidation-reduction component. The third component (PC3) represents groundwater acidity because of highly positive loading of pH. For the injection data set the variables contributed to the first component are bromide, sodium, total dissolved solids, chloride, electrical conductance, potassium, sulfate, iron, and calcium. Sulfate, magnesium, and calcium contribute to the second component and pH to the third component and represent salinity, dissolution, and acidity of groundwater. The results of the PC analysis indicate that water-rock interactions are the primary mechanism governing groundwater quality during both periods. The results of this analysis indicate that CO2 injection activities have not impacted the quality of the shallow groundwater in the project area.

AbstractOver the past 35 years, the oil and gas industry has developed many technology improvements and operating practices for injecting carbon dioxide (CO2) for enhanced oil recovery (EOR). Over this time, the US oil and gas industry has operated over 13,000 CO2 EOR wells, over 3,500 miles of high pressure CO2 pipelines and has injected over 600 million tons of CO2 without any significant safety or environmental endangerment events. Today, the US produces over 245,000 barrels of oil per day as a direct result of CO2 EOR. This presentation will describe many of the technical improvements and operational practices that have been developed as a result of the oil and gas industry’s experiences with CO 2 EOR. When these technologies and practices are applied, operators can expect facility and wellbore integrity at levels equivalent to those seen for conventional oil an d gas operations. Many of the technologies and practices that have been developed for CO2 EOR may have applicability in carbon capture and storage (CCS) projects, recognizing however, that each project should be designed to meet its site specific conditio ns. The CO2 EOR experiences of the oil and gas industry represent the largest collective base of technical information available on CO2 injection and, as such, provide valuable information for development and implementation of CCS field projects as they move forward.

Abstract Uncertainties of cooling load may make cooling system oversized. Most of previous studies implement probabilistic-based uncertainty analysis, intending to achieve optimization and reliability simultaneously. However, how to reduce the load uncertainty has received little attention. This paper investigates the impact of water storage on the design of cooling system considering load uncertainty. Information entropy is used as a convergence index of load uncertainty and used to determine how many random simulations should to be performed. A cooling system configured with water storage (system B) and another system without water storage (system A as a comparation system) are investigated in this paper. In this paper, the configure of system A and system B are optimized respectively. The result shows that the capacity distribution of system A is consistent with the distribution of extreme loads. But, the capacity distribution of system B is more concentrated as the water storage can reshape the load curve. Water storage improves the flexibility of system B. Therefore, system B is more reliable and economical than system A.

Abstract Global primary energy consumption will continue to increase with a high rate to 2050, which will be a big challenge for countries to meet both global and regional energy demand. Pumped storage stations (PSS) integrated to a hybrid power system (HPS) with solar and wind power for China are under construction to tussle with this challenge. Historically, modeling of a PSS integrated HPS has been ignored the interaction effect between the shaft vibration and the governing strategies, which will increase the dynamic risk of PSS disconnected immediately to HPS. Here we unify the models of the hydro-turbine governing system and hydro-turbine generator units with a novel expression of hydraulic forces. We quantize all the parameter’s interaction contributions of PSS integration to HPS and validate this model with the existing models. Finally, we show the feasibility of PSS’s model in integrating of a HPS under steady and fault scenarios.

AbstractIn geologic carbon sequestration, caprock fractures may act as leakage pathways, threatening the long term sealing ability of the formation. A flow-through experiment was performed to investigate fracture evolution of a fractured carbonate caprock during simulated leakage of CO2-acidified brine. The initial brine composition represented that of a CO2-saturated brine having previously reacted with the injection formation minerals resulting in a starting pH of 4.9. Experimental temperature and pressure conditions were 40 °C and 10 MPa, corresponding to injection at a depth of 1 km. A combination of X-ray computed tomography and scanning electron microscopy was used to observe fracture evolution and investigate the mineralogical changes that occurred along the fracture wall. After one week of brine flow, the cross-sectional fracture area increased by an average of 2.7 times that of the initial fracture. The fracture surface was not eroded uniformly, with the largest areas of aperture growth corresponding to direct contact between the acidified brine and calcite. This preferential dissolution of calcite led to a large increase in fracture surface roughness and in some instances, created a silicate mineral-rich microporous coating along the fracture wall. Results from this study suggest that the clay content of low permeability carbonate formations may be an important factor in controlling their long term integrity while in contact with acidified brine and should be considered when selecting appropriate injection sites for geologic CO2 sequestration.

AbstractThe aim of this work is to characterize a 5MWe Fresnel solar power plant at different areas of Algeria Sahara. These areas have been chosen for comparison by shifting the plant in different locations; namely HassiR’mel, Tamanrasset, Beni-Abbes, and El Oued. Theoretical modeling has allowed the determination of mirror optimum number to avoid shadowing effects, blocking and cosine effect. Mirror optimum number was estimated at 40 mirrors. Furthermore, a simulation was carried out on a time scale, regarding insolation, “field” and “receiver” systems. The simulation results are depicted on annual basis. Efficiency, annual energy generation and the cost per kWh are evaluated. Indeed, the calculation of efficiency differs from a site to another with values of 15.7%, 11.8%, 11.6% and 10.4%, respectively for Tamanrasset, El Oued, Beni-Abbes, HassiR’mel. Thermal performances, technical and economic results have been also evaluated for the said sites.

AbstractPre-drying is a potential way to improve the electric generation efficiency of lignite-fired power plant, and steam is a main kind of drying heat source. In conventional pre-dried lignite-fired power system, the steam extraction of regenerative system is led to the dryer directly. The steam extraction must be used by the dryer after throttling, if the energy mismatch exists between the supply of steam extraction and the need of dryer. Two systems of energy supply for the dryer, that the energy of the steam extraction is supplied to the dryer via compressor or ejector, were proposed in this paper to further increase the energy utilization efficiency. These systems were thermodynamic analyzed, and the electric generation efficiencies of these systems were compared. The energy saving boundary was gotten.