Preliminary Study of Pyrolysis and Gasification of Biomass and Thermosetting Resins for Energy Production

The gasification of the biomass is an efficient way to employ the renewable source for the production of electric power. Nevertheless, the water content in the biomass can be very high and the performances of a power plant that exploits the syngas produced can be negatively affected. The mixing of thermosetting resin with the biomass in order to increase the performances even with high moisture of the biomass is evaluated in a two stage gasifier. An Aspen Plus model that simulates the sub-processes of the gasification is implemented. The equations that describe the pyrolysis and the gasification are regressed with the data available in literature. The power production obtained with a mixture of 30% of thermosetting resins and biomass with 65% of water is higher than the ones obtained with biomass with 45% of water

enhanced geothermal system with captured co2

Abstract Post-combustion capture plants are widely studied because they represent a feasible solution to limit the CO2 emissions from existing plant. They can be applied to power plants and to industrial plants. The captured CO2 is transported to dedicated sites to be sequestrated. In this study, the captured CO2 from a coal-fired power plant is exploited to extract the geothermal energy for subsequent electric production. The system of wells consists of one of injection in a geothermal source of about 200-300 °C and one of production from which the CO2 exits at high pressure and high temperature. It is expanded in a turbine to extract part of the energy and it is cooled to be sent to the storage site. The cooling process exchanges heat with an Organic Rankine Cycle to convert the heat to electric power. The ORC plants are tested with five different substances: R245fa, HCFO, hexane, pentane, and Isobutane. The better performances are obtained with the latter two

Chemical Absorption by Aqueous Solution of Ammonia

Carbon capture is proposed as a viable way of exploiting the fossil resources for power plants and industrial processes. The post-combustion capture by chemical absorption in amine aqueous solutions has been in use in chemical and petrochemical areas for decades. As an alternative, the absorption in aqueous ammonia has received great attention recently. The carbon capture by aqueous ammonia is based on the conventional absorption-regeneration scheme applied to the ternary system CO2–NH3–H2O. It can be implemented in a chilled and a cooled process, depending upon the temperatures in the absorber and, hence, the precipitation of salts. The process simulation can be conducted in two manners: the equilibrium and the rate-based approaches. The specific heat duty is as low as 3.0, for the cooled process, and 2.2 MJ/kgCO2, for the chilled one. Moreover, the index SPECCA is as low as 2.6, for the cooled, and 2.9 MJ/kgCO2, for the chilled one. The overall energy performances from the simulations in the rate-based approach, compared against those in the equilibrium approach, result only slightly penalized. From an economic perspective, the carbon capture via chemical absorption by aqueous ammonia is a feasible retrofitting solution, yielding a cost of electricity of 82.4 €/MWhe and of avoided CO2 of 38.6 €/tCO2 for the chilled process

Thermodynamic Assessment of Cooled and Chilled Ammonia-based CO2 Capture in Air-Blown IGCC Plants

The energy impact of different post-combustion CO2 capture plants integrated in an advanced air-blown IGCC is simulated in this paper. Ammonia scrubbing is considered as the CO2 capture technology and chilled and cooled modes are investigated with reference to operation temperatures at the absorber equal to 7 °C and 20 °C respectively. Ammonia slip is controlled by means of an absorption-desorption cycle just before a final acid wash, where use of the H2S removed from the coal-derived gas at the desulphurization unit of the IGCC is made. Focusing on three levels of CO2 capture, from 80% to 90%, it is possible to appreciate that the cooled mode is promising as far as a reduction of the energy cost related to CO2 capture is concerned. As a matter of fact, the energy saving, possible when adopting an air cooling system instead of a chilling plant, is significant with the specific primary energy consumption for 90% of CO2 avoided which decreases from 2.79 MJ/kgCO2 to 2.54 MJ/kgCO2, when switching from the chilled to the cooled mode, with a difference equal to about 0.7 percentage point in IGCC efficiency

Rate-based Approaches for the Carbon Capture with Aqueous Ammonia Without Salt Precipitation

The aim of this paper is the evaluation of the influence of the kinetic of the NH3-CO2-H2O reactions in the absorber with respect to the electric power losses due to the steam bleeding from the turbine for the regeneration of the solvent. The results exposed conclude that there are few works about the kinetic of the aqueous reaction of the system NH3-CO2-H2O and data from the literature are not in agreement among them probably due to a dependence of the kinetic constants on the ammonia concentration in the liquid. The kinetic parameters have a strong influence on the specific electric power losses

Modeling of ultra super critical power plants integrated with the chilled ammonia process

Abstract As carbon dioxide anthropogenic generation and climate change appear to be correlated, carbon capture becomes necessary, in particular if applied to coal-fired power plants. The Chilled Ammonia Process (CAP) is a promising technology to be proved for the purpose. This work investigates the integration of Ultra Super Critical (USC) power plants with CAP, conducting a parametric investigation on the design parameters to find the optimum and analyzing then on the details of the power block. The commercial code Aspen Plus and the in-house research code GS are employed. With respect to a reference plant, carbon capture reduces the net electrical power by 19% and the net electrical efficiency by 8.5 percent points. The performance index SPECCA is also utilized. The optimum SPECCA is 3.18 MJ/kg CO 2 , which is to be compared to 4.2 MJ/kg CO 2 for conventional amine

Energy and exergy analyses for the carbon capture with the Chilled Ammonia Process (CAP)

Abstract Post-combustion carbon capture in existing power plants is a strategic technology that can reduce emissions from power generation. The proven approach is scrubbing with amines. However, its drawbacks are energy requirement, 3 to 5 MJ per kg of captured CO 2 , as well as solution corrosion and solvent degradation. An alternative approach is scrubbing with chilled aqueous ammonia. This technology aims at mitigating energy usage and solving corrosion and degradation issues. Here an approximate model of the CO 2 - H 2 O- NH 3 system is coupled with a proposed process to evaluate mass, energy and entropy flows. For 1 kg of captured CO 2 , the simulation yields a steam extraction of 0.59 kg, equivalent to a heat duty exceeding slightly 1.5 MJ and a generation loss approaching closely 0.1 kWh, an auxiliary consumption of 0.1 kWh and a delta of almost 0.18 kWh with respect to the ideal case. Assuming a cost of electricity of 7c/kWh, the sole operation of the capture system totals 14C/ton_ CO 2

Innovative Process Cycle with Zeolite (MS13X) for Post Combustion Adsorption

This paper reports the integration of Electric swing adsorption (ESA) Process in a Natural Gas Combined Cycle. This process was investigated in the MATESA FP7 project financed by European Commission. The ESA process is modelled through ASPEN Adsorption using both heat and electricity for regenerating the sorbent. The overall heat duty of the sorbent is 4 MJ/kgCO2 where half of this is recovered in the regeneration cycle. The resulting CO2 avoided is around 90% with a net electric efficiency of about 40%. The low efficiency is consequence of the higher energetic value of electricity with respect to the thermal power typically adopted in MEA regeneration. Being the first attempt of simulating this process using multiple heat sources and the recent development of sorbents, significant improvements can be expected by ESA reducing the gap with conventional post-combustion CO2 capture technologies

Potential performance of environmental friendly application of ORC and Flash technology in geothermal power plants

The successful exploitation of geothermal energy for power production relies on to the availability of nearly zero emission and efficient technologies, able to provide flexible operation. It can be realized with the binary cycle technology. It consists of a closed power cycle coupled to a closed geothermal loop, whereby the closed power cycle is generally accomplished by means of an organic Rankine cycle (in a few cases the Kalina cycle has been adopted). The confinement of the geothermal fluid in a closed loop is an important advantage from the environmental point of view: possible pollutants contained in the geothermal fluid are not released into the ambient and are directly reinjected underground. Although a well-established technology in the frame of geothermal applications, the adoption of the binary cycle technology is at the moment typically confined to the exploitation of medium-low temperature liquid geothermal reservoirs, generally between 100-170°C. The important advantages of the binary cycle technology from the environmental point of view suggest nevertheless that it is worthwhile to investigate whether the application range could be extended to higher temperature reservoirs, and up to which extent. Moreover, the paper investigates the effect of an increasing CO2content in the geothermal fluid. The paper compares in a convenient high temperature range of the geothermal source the performance of a properly optimized geothermal ORC plant, with the performance of a modified flash plant, whereby the geothermal steam enters a turbine, and the CO2stream is separated, compressed and finally reinjected. An environmentally friendly working fluid, recently introduced in the market, is considered in the ORC optimization process. The performance comparison will involve the assessment of plant net power. As far as the calculations are concerned, the geothermal fluid is assumed to be a mixture of water and possibly CO2. The auxiliary power consumption is properly accounted for: beyond cooling auxiliaries, a submersible well pump for the ORC plant and a gas compressor for the reinjection of the non-condensable gases in the flash plant are considered