Engineering management of gas turbine power plant co2 for microalgae biofuel production

Fossil fuel accounts for over 80% of the world`s primary energy, particularly in areas of transportation, manufacturing and domestic heating. However, depletion of fossil reserves, frequent threats to the security of fossil fuel supply, coupled with concerns over emissions of greenhouse gases associated with fossil fuel use has motivated research towards developing renewable and sustainable sources for energy fuels. Consequently, the use of microalgae culture to convert CO2 from power plants flue gases into biomass that are readily converted into biofuel offers a window of opportunities to enhance, compliment or replace fossil- fuel-use. Interest in the use of microalgae biomass for biofuel production is high as it affords the potential for power plant CO2 sequestration – (1kg of dry algae biomass uses about 1.83kg CO2). Similarly, its capacity to utilise nutrients from a variety of wastewater, sets it apart from other biomass resources. These outlined benefits all emphasis the need for extended R&D efforts to advance commercial microalgae biofuel production. The paper is aimed at investigating the environmental performance of the microalgae biofuel production process using LCA

Life cycle evaluation of an intercooled gas turbine plant used in conjunction with renewable energy

The life cycle estimation of power plants is important for gas turbine operators. With the introduction of wind energy into the grid, gas turbine operators now operate their plants in Load–Following modes as back-ups to the renewable energy sources which include wind, solar, etc. The motive behind this study is to look at how much life is consumed when an intercooled power plant with 100 MW power output is used in conjunction with wind energy. This operation causes fluctuations because the wind energy is unpredictable and overtime causes adverse effects on the life of the plant – The High Pressure Turbine Blades. Such fluctuations give rise to low cycle fatigue and creep failure of the blades depending on the operating regime used. A performance based model that is capable of estimating the life consumed of an intercooled power plant has been developed. The model has the capability of estimating the life consumed based on seasonal power demands and operations. An in-depth comparison was undertaken on the life consumed during the seasons of operation and arrives at the conclusion that during summer, the creep and low cycle life is consumed higher than the rest periods. A comparison was also made to determine the life consumed between Load–Following and stop/start operating scenarios. It was also observed that daily creep life consumption in summer was higher than the winter period in-spite of having lower average daily operating hours in a Start–Stop operating scenario

Techno-economic analysis of a sCO2 power plant for waste heat recovery in steel industry

Abstract Industrial facilities release a large amount of heat as a by-product of their processes. To improve environmental performance and increase process profitability, a portion of the waste heat can be recovered and employed for power generation by recovery systems. Supercritical carbon dioxide (sCO2) plants are emerging as potential alternatives to the well-established technologies for waste heat recovery (WHR) power generation in heavy industry. This paper offers a preliminary techno-economic analysis of a waste heat-to-power system based on a sCO2 closed-loop for a heavy-industrial process. By conducting a parametric investigation on the WHR sCO2 system's key design parameters, a number of preferable configurations from a thermodynamic perspective were initially identified; they were subsequently analyzed from the economic point of view in terms of net present value (NPV) and pay-back period (PBP). The privileged WHR system configuration achieved an overall efficiency of 30.4% and a power output of 21.6 kWe, providing an NPV of almost US k$ 376 with a PBP of approximately 4.5 years

Life-cycle assessment of self-generated electricity in Nigeria and Jatropha biodiesel as an alternative power fuel

Insufficient available energy has limited the economic growth of Nigeria. The country suffers from frequent power outages, and inconvenient black–outs while residents and industries are forced to depend on self-generated electricity. Life-cycle assessment methodology was used to assess the environmental burdens associated with self-generated electricity (SGE) and proposed embedded power generation in Nigeria. The study shows that SGE from 5 kVA diesel generators contributes to greenhouse gas (GHG) emissions of 1625 kg CO2 eq./MWh, along with other environmental burdens. Based on a point estimate of diesel electric generators in Nigeria, SGE can contribute 389 million tonnes CO2 eq. to climate change every year. This can reposition Nigeria as one of the top 20 emitters of CO2 globally. A mandatory diesel fuel displacement with Jatropha biodiesel can reduce annual GHG emissions from SGE by 76% provided combined cycle power plants are adopted for embedded power generation. The magnitude of these benefits would depend on material inputs, seed yield as well as the environmental status of the reference fuel. Minimal use of fertilizers, chemicals and resources and fossil fuel substitution with renewable options can minimize adverse environmental burdens

Process modelling and simulation of degradation of 2-amino-2-methyl-1-propanol (AMP) capture plant

The presence of contaminants in the flue gas stream such as O2, CO2, SOX, and NOX can cause solvent degradation in solvent-based CO2 capture processes. In this study, the major degradation products reactions of the AMP-based CO2 capture process has been included in the Aspen Plus® V8.4 simulation software using equilibrium reactions. Assessing the solvent degradation, solvent concentration and flowrate were varied. The results showed that the AMP losses reduced by decreasing solvent flowrate and concentration. Largest energy savings are observed when increasing concentration up to 34 wt. %

Membrane protein remodeling in microglia exposed to amyloid peptides

Infection, neurodegeneration, and other conditions associated with loss of brain homeostasis, induce changes in microglial morphology, gene expression and function, generally referred to as “activation”. Alzheimer’s disease (AD) is the most common dementia and is characterized by neuroinfammatory changes, including alterations in the morphology and distribution of microglia and astrocytes, and deposition of complement and other infammatory mediators. Our previous observations show that microglial cells challenged in vitro with amyloid peptides clustered and rounded up, dramatically changing their morphology. Besides, in these cells we observed the early acetylation and then the phosphorylation of STAT3 which is required for the expression of the epsilon isoform of 14-3-3, a marker of Abeta-activated microglia (1, 2). We applied afnity partitioning approach combined with high throughput mass spectrometric analysis in order to identify variation of proteins on plasma membrane of BV2 immortalized microglia upon treatment with amyloid peptides. By this method several proteins up- or down-regulated by amyloid treatment were identifed in microglial plasma membrane. Among them annexins (5 and 7), IFITM3 and MARK3. These data have been confrmed in primary microglial cultures. In microglia, plasma membrane plays a relevant role in the cross-talking with the external neuronal environment and in the resulting trophic or infammatory response of these sentinel cells. As such, knowledge of the microglia responsiveness to beta amyloids in term of changes in its plasma membrane proteome is imperative for unveiling the molecular landscape in which AD occurs

The dental management of patients at risk of medication-related osteonecrosis of the jaw: New paradigm of primary prevention

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse reaction of antiresorptive and antiangiogenic agents; it is a potentially painful and debilitating condition that can considerably affect the quality of life of patients. Furthermore, even if its epidemiology and pathogenesis have still not been fully clarified, several risk factors related to MRONJ have been recognized in prevention protocols. Three main risk factors are as follows: (i) the type of ONJ-related medications: antiresorptive (e.g., Bisphosphonates, Denosumab) and antiangiogenic drugs (e.g., Bevacizumab, Sunitinib); (ii) the category of patient at MRONJ risk: cancer versus non-cancer patient; (iii) the typologies and timing of dental treatments (e.g., before, during, or after the drug administration). The aim of this paper is to describe the new paradigm by the Italian Society of Oral Pathology and Medicine (SIPMO) on preventive dental management in patients at risk of MRONJ, prior to and during/after the administration of the aforementioned ONJ-related drugs. In reducing the risk of MRONJ, dentists and oral hygienists are key figures in applying a correct protocol of primary prevention for pre-treatment and in-treatment patients. However, the necessity of a multidisciplinary standardized approach, with a sustained dialogue among specialists involved, should be always adopted in order to improve the efficacy of preventive strategies and to ameliorate the patient\u2019s quality of life

Techno-economic evaluation of the 2-amino-2-methyl-1-propanol (AMP) process for CO2 capture from natural gas combined cycle power plant

It is widely accepted that emissions of CO2, which is a major greenhouse gas, are the primary cause of climate change. This has led to the development of carbon capture and storage (CCS) technologies in which CO2 is captured from large-scale point sources such as power plants. However, retrofits of carbon capture plants result in high efficiency penalties, which have been reported to fall in the range of 7–12% points in the case of post-combustion capture from natural gas-fired power plants. Therefore, a reduction of these efficiency losses is a high priority in order to deploy CCS at a large scale. At the moment, chemical solvent scrubbing using amines, such as monoethanolamine (MEA), is considered as the most mature option for CO2 capture from fossil fuel-fired power plants. However, due to high heat requirements for solvent regeneration, and thus high associated efficiency penalties, the use of alternative solvents has been considered to reduce the energy demand. In this study, a techno-economic assessment of the post-combustion CO2 capture process using 2-amino-2-methyl-1-propanol (AMP) for decarbonisation of a natural gas combined cycle (NGCC) power plant was performed. The thermodynamic assessment revealed that the AMP-based process resulted in 25.6% lower reboiler duty compared to that of the MEA-based process. This was primarily because the AMP solvent can be regenerated at a higher temperature (140 °C) and pressure (3.5 bar) compared to that of MEA (120 °C and 1.8 bar). Furthermore, the efficiency penalty due to the retrofit of the AMP-based process with the natural gas combined cycle power plant was estimated to be 7.1% points, compared to 9.1% points in the case of integration with the MEA-based process. Regardless of the superior thermodynamic performance, the economic performance of the AMP-based process was shown to be better than that of the MEA-based process only for make-up rates below 0.03%. Therefore, use of AMP as a solvent in chemical solvent scrubbing may not be the most feasible option from the economic standpoint, even though it can significantly reduce the efficiency penalty associated with CO2 capture from NGCCs

Prophylactic chimera anterolateral thigh/vastus lateralis flap: preventing complications in high-risk head and neck reconstruction

PURPOSE: In high-risk head and neck cases treated with tumor resection and associated radical neck dissection, orocutaneous fistulas and wound breakdowns in the neck are relatively frequent and can have serious consequences, such as carotid blowout syndrome (CBS), the need for salvage reoperations, and prolonged recovery time. The authors present the application of a prophylactic chimeric anterolateral thigh (ALT) and vastus lateralis (VL) flap to prevent complications. MATERIALS AND METHODS: A retrospective review was performed of a historical group (96 patients) of patients with head and neck cancer treated with tumor resection, radical neck dissection, and microsurgical reconstruction of the tumor site only and a prospective cohort (21 patients) in which a chimeric ALT-VL flap was used to simultaneously reconstruct the tumor site and sternocleidomastoid muscle to fill dead space and protect the carotid artery. RESULTS: The rate of complications was higher in the historical group: CBS occurred in 4.1% and orocutaneous fistulas in 11.5% of patients; 5.2% of patients required major salvage surgery for a wound complication. In the cohort group, no CBS or orocutaneous fistula occurred and no major salvage surgical procedure was needed. CONCLUSIONS: Prophylactic ALT-VL flaps in high-risk head and neck cancers provide adequate and long-lasting soft tissue coverage for the carotid artery, with minimal additional morbidity, and could be beneficial in preventing serious and life-threatening wound complications and the need for reoperatio