首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
In this work, the Aspen Hysys conceptual design of a new process for energy generation at large scale with implicit CO2 capture is presented. This process makes use of the CaO capability for CO2 capture at high temperature and the possibility of regenerating this sorbent working in interconnected fluidised bed reactors operating at different temperatures. The proposed process has the advantage of producing power with minimum CO2 emissions and very low energy penalties compared with similar air-based combustion power plants. In this system, five main parts can be distinguished: the combustor where coal is burnt with air, the calciner where the fresh and the recycled CaCO3 is calcined, the carbonator where the CO2 produced in the combustor is captured, the supercritical steam cycle and the CO2 compression system. In this arrangement, the three fluidised bed reactors are interconnected in such a way that it is possible to perform the CaCO3 calcination at a temperature of 950 °C with the energy transported by a hot solid stream produced in the circulating fluidised bed combustor operating at 1030 °C. The stream rich in CaO produced in the calciner is split into three parts. One of them is transported to the carbonator operating at 650 °C where most of the CO2 in the flue gas produced in the combustor is captured. The second one is sent to the combustor, where it is heated up and used as energy carrier. The third solid stream that leaves the calciner is a purge in order to maintain the capture system activity and to avoid inert material accumulation. Because of the high temperatures involved in all the system, it is possible to recover most of the energy in the fuel and to produce power in a supercritical steam cycle. A case study is presented and it is demonstrated that under these operating conditions, 90% CO2 capture efficiency can be achieved with no energy penalty further than the one originated in the CO2 compression system.  相似文献   

2.
A novel concept for capturing CO2 from biomass combustion using CaO as an active solid sorbent of CO2 is discussed and experimentally tested. According to the CaO/CaCO3 equilibrium, if a fuel could be burned at a sufficiently low temperature (below 700 °C) it would be possible to capture CO2in situ” with the CaO particles at atmospheric pressure. A subsequent step involving the regeneration of CaCO3 in a calciner operating at typical conditions of oxyfired-circulating fluidized combustion would deliver the CO2 ready for purification, compression and permanent geological storage. Several series of experiments to prove this concept have been conducted in a 30 kW interconnected fluidized bed test facility at INCAR-CSIC, made up of two interconnected circulating fluidized bed reactors, one acting as biomass combustor-carbonator and the other as air-fired calciner (which is considered to yield similar sorbent properties than those of an oxyfired calciner). CO2 capture efficiencies in dynamic tests in the combustor-carbonator reactor were measured over a wide range of operating conditions, including different superficial gas velocities, solids circulation rates, excess air above stoichiometric, and biomass type (olive pits, saw dust and pellets). Biomass combustion in air is effective at temperatures even below the 700 °C, necessary for the effective capture of CO2 by carbonation of CaO. Overall CO2 capture efficiencies in the combustor-carbonator higher than 70% can be achieved with sufficiently high solids circulation rates of CaO and solids inventories. The application of a simple reactor model for the combined combustion and CO2 capture reactions allows an efficiency factor to be obtained from the dynamic experimental test that could be valuable for scaling up purposes.  相似文献   

3.
While the demand for reduction in CO2 emission is increasing, the cost of the CO2 capture processes remains a limiting factor for large-scale application. Reducing the cost of the capture system by improving the process and the solvent used must have a priority in order to apply this technology in the future. In this paper, a definition of the economic baseline for post-combustion CO2 capture from 600 MWe bituminous coal-fired power plant is described. The baseline capture process is based on 30% (by weight) aqueous solution of monoethanolamine (MEA). A process model has been developed previously using the Aspen Plus simulation programme where the baseline CO2-removal has been chosen to be 90%. The results from the process modelling have provided the required input data to the economic modelling. Depending on the baseline technical and economical results, an economical parameter study for a CO2 capture process based on absorption/desorption with MEA solutions was performed.Major capture cost reductions can be realized by optimizing the lean solvent loading, the amine solvent concentration, as well as the stripper operating pressure. A minimum CO2 avoided cost of € 33 tonne−1 CO2 was found for a lean solvent loading of 0.3 mol CO2/mol MEA, using a 40 wt.% MEA solution and a stripper operating pressure of 210 kPa. At these conditions 3.0 GJ/tonne CO2 of thermal energy was used for the solvent regeneration. This translates to a € 22 MWh−1 increase in the cost of electricity, compared to € 31.4 MWh−1 for the power plant without capture.  相似文献   

4.
There is strong world-wide interest in developing new and improved processes for post-combustion capture of CO2, often using chemical absorption. Developers of new processes make positive claims for their proposals in terms of low energy consumption, but these are usually difficult to validate. This paper demonstrates that rigorous application of thermodynamic analysis and process simulation provides a powerful way to quantitatively estimate the energy requirements of CO2-capture processes by applying the methodology to the analysis and evaluation of the chilled-ammonia process.  相似文献   

5.
In order to evaluate the risk of hydrate formation in CO2 transport one has to be able to predict the water content in the fluid phase in equilibrium with the CO2-hydrate. A literature review has identified some knowledge gaps, for example, there are no results available at temperatures lower than 243.15 K (?30 °C); and none of the models found in literature predicts the water content with high accuracy. A model based on equality of water fugacity in fluid and hydrate phase is presented here and used for the predictions of water content in equilibrium with hydrates. Although this model gives better accuracy in the overall temperature and pressure ranges of measurements than the models found in the literature, it is not accurate enough to satisfy the requirements of CO2 transport. The simulation results also show that it is possible to form hydrate at low water content, such as xw = 50 vppm, if temperature is low enough. In order to verify the results and improve the model accuracy further, more experimental data in a larger temperature and pressure region are required.  相似文献   

6.
The emission of fossil fuel carbon dioxide (CO2) to the atmosphere is implicated as the predominant cause of global climate change; therefore, advanced CO2 capture technologies are of the utmost importance. In this study, innovative amine-multilayered sorbents were fabricated using layer-by-layer (LbL) nanoassembly technology via alternate deposition of a CO2-adsorbing amine polymer (e.g. polyethylenimine or PEI) and an oppositely-charged polymer (e.g. polystyrene sulfonate or PSS). We found that the developed sorbents could be used for CO2 capture and that LbL nanoassembly allows us to engineer their CO2 capture performance through the fabrication variables (e.g. deposition polymers, deposition media, and number of bilayers). PEI/PSS was found to be the best polymer combination for developing sorbents with relatively high CO2 capture capacity. The amine-multilayered solid sorbents possessed fine microstructures and may have similar polymer deposition within and on the surface of solid sorbents. These amine-multilayered sorbents had much faster CO2 desorption rates compared to sorbents prepared using the current PEI-impregnation approach. Such fast CO2 desorption could make sorbents a good option for CO2 removal from power plants and even the atmosphere.  相似文献   

7.
The transcritical CO2 Rankine cycle with liquefied natural gas (LNG) as cold source is a promising power system to utilize mid- and low-temperature heat source. Most previous works focused on thermodynamic and thermoeconomic analysis or optimization for the system. In this article, an off-design performance analysis for the system is conducted. An off-design mathematical model for the system is established to examine the variation of system performance with the variations of heat source mass flow rate and temperature. A modified sliding pressure regulation control strategy, which regulates turbine inlet pressure to keep the temperature difference between heat source temperature and turbine inlet temperature constant, is applied to control the system when off-design conditions happen. The results show that when the mass flow rate or the temperature of heat source is less or lower than that of design condition, both the net power output of system and the system exergy efficiency decrease, whereas when they are more or higher than the values of design condition, the net power output of system increases but the system exergy efficiency still decreases. In addition, both CO2 turbine and NG turbine could almost keep the designed efficiency values under the applied control strategy.  相似文献   

8.
Coalbed methane is an important resource of energy. Meanwhile CO2 sequestration in coal is a potential management option for greenhouse gas emissions. An attractive aspect to this process is that CO2 is adsorbed to the coal, reducing the risk of CO2 migration to the surface. Another aspect to this is that the injected CO2 could displace adsorbed methane leading to enhanced coalbed methane recovery. Therefore, in order to understand gas migration within the reservoir, mixed-gas adsorption models are required. Moreover, coal reservoir permeability will be significantly affected by adsorption-induced coal swelling during CO2 injection. Coal swelling is directly related to reservoir pressure and gas content which is calculated by adsorption models in reservoir simulation. Various models have been studied to describe the pure- and mixed-gas adsorption on coal. Nevertheless, only the Langmuir and Extended Langmuir models are usually applied in coal reservoir simulations. This paper presents simulation work using several approaches to representing gas adsorption, implemented into the coal seam gas reservoir simulator SIMED II. The adsorption models are the Extended Langmuir model (ELM), the Ideal Adsorbed Solution (IAS) model and the Two-Dimensional Equation of State (2D EOS). The simulations based on one Australian and one American coal sample demonstrated that (1) the Ideal Adsorbed Solution model, in conjunction with Langmuir model as single-component isotherm, shows similar simulation results as the ELM for both coals, with the IAS model representing the experimental adsorption data more accurately than the ELM for one coal and identically with the ELM for the other coal; (2) simulation results using the 2D EOS, however, are significantly different to the ELM or IAS model for both coal samples. The magnitude of the difference is also dependent on coal swelling and the well operating conditions, such as injection pressure.  相似文献   

9.
The In Salah Gas Joint Venture CO2 storage project has been in operation in Algeria since 2004 and is currently the world's largest onshore CO2 storage project. CO2 is injected into the saline aquifer of a gas reservoir several kilometres away from the gas producers. Current focus in the project is on implementing a comprehensive monitoring strategy and modelling the injection behaviour in order to ensure and verify safe long-term storage. A key part of this effort is the understanding of the processes involved in CO2 migration within relatively low-permeability sandstones and shales influenced by fractures and faults. We summarise our current understanding of the fault and fracture pattern at this site and show preliminary forecasts of the system performance using discrete fracture models and fluid flow simulations. Despite evidence of fractures at the reservoir/aquifer level, the thick mudstone caprock sequence is expected to provide an effective flow and mechanical seal for the storage system; however, quantification of the effects of fracture flow is essential to the site verification.  相似文献   

10.
Following the feasibility study of sour compression process as a novel purification method of producing NOx-free, SO2-free oxyfuel-derived CO2 using actual fluegas, in this paper, we present the study of the individual reactions taking place in the process in a controlled environment. We have previously showed that an increase of NO/NO2 concentration in the inlet stream is beneficial for SO2 removal as NO2 promotes SO2 oxidation and the further removal as liquid acid. In this study we show that the reaction SO2 + NO2  SO3 + NO does not take place significantly in the absence of liquid water at a range of conditions relevant to the sour compression process. When liquid water is present, SO2 is oxidised by NO2 regenerating NO with the rate of conversion of SO2 being dependent on the acid concentration in the liquid. The formation of small liquid droplets where very low levels of pH (?0) can be reached is shown to be of great importance to the SO2 + NO2 conversion process.  相似文献   

11.
When integrating a post-combustion CO2 capture process and CO2 compression into a steam power plant, the three interface quantities heat, electricity and cooling duty must be satisfied by the power plant, leading to a loss in net efficiency. The heat duty shows to be the largest contributor to the overall net efficiency penalty of the power plant. Additional energy penalty results from the cooling and electric power duty of the capture and compression units.In this work, the dependency of the energy penalty on the quantity and quality of the heat duty is analyzed and quantified for a state-of-the-art hard coal fired power plant. Furthermore, the energy penalty attributed to the additional cooling and power duty is quantified. As a result correlations are provided which enable to predict the impact of the heat, cooling and electricity duty of post-combustion CO2 capture processes on the net output of a steam power plant in a holistic approach.  相似文献   

12.
The CO2 storage capacity of geological reservoirs is of great interest for the selection of potential storage sites in carbon capture and storage (CCS) projects. A detailed analysis essentially requires a thorough understanding of the interaction of forces acting within the system. By defining characteristic quantities for length, time, pressure and velocity, the governing multiphase flow equations can be non-dimensionalised. This allows for the definition of physically sound dimensionless numbers, resembling the ratios of acting forces like viscous, capillary and gravitational forces. An analysis of the relation of forces in reservoirs with different parameter setups allows their intercomparison with respect to their CO2 storage capacity potential. To back up the analysis, a comprehensive reservoir parameter database with more than 1200 reservoirs is analysed and statistical characteristics are derived. Effects of reservoir parameters like depth, temperature, absolute and relative permeability, as well as capillary pressure are investigated. It is shown that dimensionless numbers can be used to qualitatively order reservoirs with respect to the forces acting in the reservoir. Moreover, it is shown that the relative permeability relations together with the residual saturations have a great influence on the balance of forces.  相似文献   

13.
The membrane separation process for CO2 capture can be interfered by the gaseous components and the fine particles in flue gas, especially in desulfurized flue gas. In this work, the pint-sized Polyimide(PI) hollow fiber membrane contactors were self-packed to investigate the membrane CO2 separation from flue gas containing fine particles and gaseous contaminants (SO2,SO3,H2O). First, the effects of SO2, SO3, water vapor, and gypsum particles on the CO2 capture were studied independently and synergistically. The results showed that the effect of SO2 on the membrane separation properties is indistinctive; however, the membrane performance was damaged seriously with the addition of SO3. The high humidity promoted the CO2 separation initially before inhibiting the PI membrane performance. Moreover, the decrease of the CO2/N2 selectivity and the permeation rate were accelerated with the coexistence of SO2. The membrane performance showed an obvious deterioration in the presence of gypsum particles, with a 21% decrease in the CO2/N2 selectivity and 51% decrease in the permeation rate. Furthermore, the gypsum particles exerted dramatic damage. Under the WFGD conditions, the combined effects of SO2, water vapor, and the gypsum particles influenced the stability of the membrane significantly. This tendency is mainly attributed to the deposition of fine particles and aerosol on the membrane surface, which occupied the effective area and enhanced the mass transfer resistance. This study of impurities’ influence could play an important role in further industrial application of membrane CO2 capture.  相似文献   

14.
This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (<0.05 mol L?1). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption–oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.  相似文献   

15.
Adsorption is one of the most promising technologies for reducing CO2 emissions and at present several different types of sorbents are being investigated. The use of sorbents obtained from low-cost and abundant precursors (i.e. solid wastes) appears an attractive strategy to adopt because it will contribute to a reduction not only in operational costs but also in the amount of waste that is dumped and burned in landfills every year. Following on from previous studies by the authors, in this work several carbon-based adsorbents were developed from different carpet wastes (pre-consumer and post-consumer wastes) by chemical activation with KOH at various activation temperatures (600–900 °C) and KOH:char impregnation ratios (0.5:1 to 4:1). The prepared materials were characterised by chemical analysis and gas adsorption (N2, −196 °C; CO2, 0 °C), and tested for CO2 adsorption at temperatures of 25 and 100 °C. It was found that both the type of precursor and the conditions of activation (i.e. impregnation ratios, and activation temperatures), had a huge influence on the microporosity of the resultant samples and their CO2 capture capacities. The carbon-based adsorbent that presented the maximum CO2 capture capacities at 25 and 100 °C (13.8 wt.% and 3.1 wt.%, respectively), was prepared from a pre-consumer carpet waste and was activated at 700 °C using a KOH:char impregnation ratio of 1:1. This sample showed the highest narrow microporosity volume (0.47 cm3 g−1), thus confirming that only pores of less than 1 nm are effective for CO2 adsorption at atmospheric pressure.  相似文献   

16.
Site selection in CO2 ocean sequestration is examined based on the idea that a site where injected CO2 is efficiently diluted is favourable in reducing/avoiding biological impacts. Simulations of CO2 injection into several sites by an eddy-resolving oceanic general circulation model (OGCM) show that the maximum CO2 concentration differs by a factor of 10 among sites. The distribution of eddy activity is the most important causative factor producing the geographical differences in CO2 dilution. Based on the relationship between the maximum CO2 concentration and eddy activity, we estimated the distribution of the maximum CO2 injection rate by a proposed method, which does not cause chronic impacts on biota. Around Japan, extensive ocean volume has the potential to dilute 20 million tonnes per year without chronic impacts, and some areas can be injected with 80 million tonnes per year.  相似文献   

17.
This study provides insight into the feasibility of a CO2 trunkline from the Netherlands to the Utsira formation in the Norwegian part of the North Sea, which is a large geological storage reservoir for CO2. The feasibility is investigated in competition with CO2 storage in onshore and near-offshore sinks in the Netherlands. Least-cost modelling with a MARKAL model in combination with ArcGIS was used to assess the cost-effectiveness of the trunkline as part of a Dutch greenhouse gas emission reduction strategy for the Dutch electricity sector and CO2 intensive industry. The results show that under the condition that a CO2 permit price increases from €25 per tCO2 in 2010 to €60 per tCO2 in 2030, and remains at this level up to 2050, CO2 emissions in the Netherlands could reduce with 67% in 2050 compared to 1990, and investment in the Utsira trunkline may be cost-effective from 2020–2030 provided that Belgian and German CO2 is transported and stored via the Netherlands as well. In this case, by 2050 more than 2.1 GtCO2 would have been transported from the Netherlands to the Utsira formation. However, if the Utsira trunkline is not used for transportation of CO2 from Belgium and Germany, it may become cost-effective 10 years later, and less than 1.3 GtCO2 from the Netherlands would have been stored in the Utsira formation by 2050. On the short term, CO2 storage in Dutch fields appears more cost-effective than in the Utsira formation, but as yet there are major uncertainties related to the timing and effective exploitation of the Dutch offshore storage opportunities.  相似文献   

18.
Calcium looping (CaL) is a promising post-combustion CO2 capture technology which is carried out in a dual fluidized bed (DFB) system with continuous looping of CaO, the CO2 carrier, between two beds. The system consists of a carbonator, where flue gas CO2 is adsorbed by CaO and a regenerator, where captured CO2 is released. The CO2-rich regenerator flue gas can be sequestered after gas processing and compression. A parametric study was conducted on the 10 kWth DFB facility at the University of Stuttgart, which consists of a bubbling fluidized bed carbonator and a riser regenerator. The effect of the following parameters on CO2 capture efficiency was investigated: carbonator space time, carbonator temperature and calcium looping ratio. The active space time in the carbonator, which is a function of the space time and the calcium looping ratio, was found to strongly correlate with the CO2 capture efficiency. BET and BJH techniques provided surface area and pore volume distribution data, respectively, for collected sorbent samples. The rate of sorbent attrition was found to be 2 wt.%/h which is below the expected sorbent make-up rate required to maintain sufficient sorbent activity. Steady-state CO2 capture efficiencies greater than 90% were achieved for different combinations of operational parameters. Moreover, the experimental results obtained were briefly compared with results derived from reactor modeling studies. Finally, the implications of the experimental results with respect to commercialization of the CaL process have been assessed.  相似文献   

19.
In this paper, we propose the return-to-cost-ratio (RCR) as an alternative approach to the analysis of operational eco-efficiency of companies based on the notion of opportunity costs. RCR helps to overcome two fundamental deficits of existing approaches to eco-efficiency. (1) It translates eco-efficiency into managerial terms by applying the well-established notion of opportunity costs to eco-efficiency analysis. (2) RCR allows to identify and quantify the drivers behind changes in corporate eco-efficiency. RCR is applied to the analysis of the CO2-efficiency of German companies in order to illustrate its usefulness for a detailed analysis of changes in corporate eco-efficiency as well as for the development of effective environmental strategies.  相似文献   

20.
A reaction calorimeter was used to determine the enthalpies of absorption of CO2 in aqueous ammonia and in aqueous solutions of ammonium carbonate at temperatures of 35–80 °C. The heat of absorption of CO2 with 2.5 wt% aqueous ammonia solution was found to be about 70 kJ/mol CO2, which is lower than that with MEA (around 85 kJ/mol) at 35 and 40 °C. The value decreases with increased loading, but not to as low a value as expected by the carbonate–bicarbonate reaction (26.88 kJ/mol). The enthalpy of absorption of CO2 in aqueous ammonia at 60 and 80 °C decreases with loadings at first, then increases between 0.2 mol CO2/mol NH3 and 0.6 mol CO2/mol NH3, and then decreases again. The behavior of the heat of absorption of CO2 in 10 wt% ammonium carbonate solution was found to be the same as that of aqueous ammonia at loadings above 0.6 mol CO2/mol NH3. The heat of absorption increases with increasing temperature. The heats of absorption are directly related to the extent of the various reactions with CO2 and can be assessed from the species variation in the liquid phase.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号