The power sector needs to be decarbonised by 2050 to meet the global target for greenhouse gas emission reduction and prevent climate change. With fossil fuels expected to play a vital role in the future energy portfolio and high efficiency penalties related to mature CO 2 capture technologies, this research aimed at evaluating the efficiencyimprovements and alternate operating modes of the coal-firedpowerplants (CFPP) retrofitted with post-combustion CO 2 capture. To meet this aim, process models of the CFPPs, chilled ammonia process (CAP) and calcium looping (CaL) were developed in Aspen Plus ® and benchmarked against data available in the literature. Also, the process model of chemical solvent scrubbing using monoethanolamine (MEA) was adapted from previous studies. Base-load analysis of the 580 MW el CFPP retrofits revealed that if novel CAP retrofit configurations were employed, in which a new auxiliary steam turbine was coupled with the boiler feedwater pump for extracted steam pressure control, the net efficiency penalty was 8.7–8.8% points. This was close to the 9.5% points in the MEA retrofit scenario. Conversely, CaL retrofit resulted in a net efficiency penalty of 6.7–7.9% points, depending on the fuel used in the calciner. Importantly, when the optimised supercritical CO 2 cycle was used instead of the steam cycle for heat recovery, this figure was reduced to 5.8% points. Considering part-load operation of the 660 MW el CFPP and uncertainty in the process model inputs, the most probable net efficiency penalties of the CaL and MEA retrofits were 9.5% and 11.5% points, respectively. Importantly, in the CaL retrofit scenarios, the net power output was found to be around 40% higher than that of the CFPP without CO 2 capture and double than that for the MEA retrofit scenario. Such performance of the CaL retrofit scenario led to higher profit than that of the 660 MW el CFPP without CO 2 capture, especially if its inherent energy storage capability was utilised. Hence, this study revealed that CaL has the potential to significantly reduce the efficiency and economic penalties associated with mature CO 2 capture technologies.
In order to complete the overview on the novel PSA-based system configurations, a comparative analysis is carried out with the most common arrangement for power and ultrapure H2 coproduction in IGCC plants. It consists of an absorption unit for processing the shifted syngas followed by a PSA for further H2 purification. The related results refer to two studies, selected after a screening of the relevant literature. Intro- ducing the production of ultrapure H2 appears to be more effective when also the CO2 separation is carried out through a PSA process, as can be argued by the cumulative efficiency. The main advantage is that PSA technology allows avoiding the power consumption related to PSA tail gas compression, common in the configuration including absorption. Between the two proposed options, the Two-train PSA configuration demonstrated to perform better in terms of energy efficiency. Although the discussed advantages of the novel configu- rations presented, the general viability has yet to be proven since PSA integration into an IGCC plant has normally a lower overall performance than absorption. It needs to be evaluated if the benefits introduced with ultrapure H2 coproduction are sufficient to make up for this initial performance gap. The scattering of results in the literature makes this evaluation not straightforward. A possible solution would be to utilize a common modeling framework to assess the performance of both options. Other issues may also arise when adopting PSA technology, among those the need for controlling the fluctu- ations in the H2-rich gas rate to the gas turbine due to the PSA cyclic operation. Lastly, this is a very first assessment of such system entirely based on PSA technology. A further optimi- zation is likely feasible, exploiting developments in the pro- cesses and in the materials (e.g. adsorbents effectively performing at high temperatures allowing for warm gas cleaning processes). Moreover a simplification of the PSA layout is possible with advantages in terms of footprint. In particular the Two-train PSA configuration relies on a fairly complex second PSA cycle, which was developed to obtain high H2 recovery. Since that is not an important requirement in the case proposed, an easier PSA cycle could be advisable.
Rotary air preheater is one of the important energy recovery systems in the steam power plant which was first introduced in 1920 by Ljungstrom . The main function is to primarily preheat the combustion air for rapid and efficient combustion in the furnace serving as the last heat trap for the boiler system, a regenerative air preheater typically accounts for over 10% of a plants thermal efficiency on a typical steam generator. Considering this, when evaluating the performance of an air preheater one should take into account all of the process variables. A very good method to improve the overall efficiency of a thermal power plant is to preheat the air. If the incoming air for combustion is not preheated, then some energy must be supplied to heat the air to a temperature required to facilitate combustion. As a result, more fuel will be consumed which increases the overall cost and decreases the efficiency. There are many factors, which contribute to the deterioration of air preheater performance like high
The main source of worldwide CO 2 emission is the combustion of fossil fuel, such as petroleum, crude oil, natural gas and coal . Amongst them, coal-firedpowerplants offer some advantages to operators, not only because of high availability of coal compared to other nature fuels, but also due to its flexible operation to changes in supply and demand . However, the amount of CO2 emission per unit of electricity released by coal-firedpowerplants is twice as much as their natural gas counterparts . As a result, many researches have been explored to reduce the CO 2 gas emission from coal-firedpowerplants. Carbon capture and sequestration (CCS) is identified as an appropriate technique for the sustainability of coal- firedpower plant, because of its efficiency and effectiveness in reducing CO 2 emission . Amongst the various technologies of CCS, the post-combustion carbon capture technology with chemical absorption has been considered as the most suitable way to reduce CO 2 emission. This is because it can retrofit the existing coal-firedpower plant easily and treat flue gas stream with low CO 2 partial pressure . However, it still has some disadvantages, one of which is the large energy requirement for absorbent regeneration. The thermal energy for regeneration usually comes from extracted steam from the low pressure steam turbines, which will reduce the efficiency of the coal-firedpower plant. Therefore, it is particularly important to find out the trade-off between CO 2 capture level and energy consumption by using process optimisation. In order to carry out process optimisation, it is necessary to develop an accurate model for the post-combustion carbon capture process.
emissions. The UK Government stated in their 2009 UK Low Carbon Transition Plan  that they intended to support the construction of up to four CCS demonstrators linked to coal-ﬁred power stations by 2014–2015. In addition, it proposed to place a requirement on any new coalpower stations to demonstrate this technology. Scrase and Watson  discussed the limitations to this strategy, which involve an element of ‘picking winners’ (via the UK Govern- ment’s CCS demonstrator competition, based only on post- combustioncapture technologies). They noted that the uncertain- ties over full-scale power plant CCS technical performance and costs may only become clearer when the ﬁrst demonstrators are operational in perhaps ﬁve years time. The present study has attempted to reduce these uncertainties by way of indicative esti- mates of the techno-economic performance of both modern and advanced UK power plant/CCS chain options over their whole chain: from power stations to typical storage reservoir. In addition to carbon mitigation on the supply-side, it is clearly important to reduce energy demand in the UK and elsewhere. This could be achieved, in part, by the array of methods available to improve the efﬁciency with which energy is produced and consumed  . That would mitigate against climate change and enhance energy security.
None of the above-mentioned literature has reported the impact of biomass on powerplants integrated with a carbon capture technology. A techno-economic assessment of a standalone biomass firedpower plant with two different kinds of CCS technologies, including PCC and oxy-fuel system, have compared the cost and emissions incentives to that of a coalfiredpower plant using IECM (Al-Qayim et al., 2015). IEA (2009) reported different case studies for the co-firing of biomass with coal for different technologies, including pulverised fuel firing, circulating fluidised bed firing and bubbling fluidised bed firing. Similarly, the same results as that of the IEA (2009) have been reported in (Domenichini et al., 2011). Benchmarking comparison of NGCC, coal and biomass firedpowerplants integrated with a MEA-based CO 2
The regeneration heat for a polyethyleneimine (PEI)/silica adsorbent based carbon capture system is ﬁrst assessed in order to evaluate its effect on the efﬁciency penalty of a coal or natural gas power plant. Process simulations are then carried out on the net plant efﬁciencies for a speciﬁc supercritical 550 MWe pulverized coal (PC) and a 555 MWe natural gas combined cycle (NGCC) power plant integrated with a conceptually designed capture system using ﬂuidized beds and PEI/silica adsorbent. A benchmark system applying an advanced MEA absorption technology in a NETL report (2010) is used as a reference system. Using the conservatively estimated parameters, the net plant efﬁciency of the PC and NGCC power plant with the proposed capture system is found to be 1.5% and 0.6% point higher than the reference PC and NGCC systems, respectively. Sensitivity analysis has revealed that the moisture adsorption, working capacity and heat recovery strategies are the most inﬂuential parameters to the power plant efﬁciency. Under an optimal scenario with improvements in increasing the working capacity by 2% points and decreasing moisture adsorption by 1% point, the plant efﬁciencies with the proposed capture system are 2.7% (PC) and 1.9% (NGCC) points higher than the reference systems.
Presently, coal-firedpowerplants play a key role in the German energy system, despite the fact that environmen- tal concerns about the coal sector prevail already for a long time (see, e.g., ). With an annual electricity pro- duction of 273 TWh, coal-firedpowerplants provide al- most 46% of the electricity that is consumed in Germany . Because of the high level of availability, the coal-firedplants are extensively used for supplying the baseload de- mand for electricity. They play a crucial role in balancing fluctuations in the electricity production of renewables. Politico-economic considerations are––at least region- ally––also of high importance in the coal sector due to ap- proximately 35,000 people employed in this sector (incl. coal mining and the power stations themselves) . At the same time, coal-firedpowerplants are a big perpetra- tor of global warming due to greenhouse gas (GHG) emis- sions. In Germany, these powerplants emit 255 million tons of CO 2 each year which corresponds to 36% of the
Mercury is emitted in several chemical forms or oxidation states, including elemental and oxidized mercury, which impact not only in its removal but also on its transport and subsequent deposition once released into the atmosphere . Mercury is probably the trace element of most environmental concern, as it tends to bio-accumulate in the food chain once released into the environment. Mercury is primarily emitted as a vapor and is not effectively controlled by the pollution control equipment used during most of the 20th century. However, activated carbon injection in the flue gas results in the adherence of mercury molecules on the carbon particles which are then recovered in fabric bags through which the gas is filtered. This is the control system used in WTE plants that have implemented the MACT regulations.
2.3.1. Gasi ﬁ cation. A dry feed type entrained ﬂow shell gasiﬁer is considered in this work due to its dominance in the commercial IGCC plant designs. An RYIELD reactor block is used to decompose the pulverized coal powder into its conventional constituent elements and also calculates the heat required for it. RYIELD reactors are used where inlets are unknown and the outlets known. The conventional elements provided after decomposition of coal are fed to the RGIBBS reactor block, which determines the possible products and their composition at equilibrium conditions. The RGIBBS reactor is an equilibrium based reactor, which restricts individual equations to equilibrium and does not take account of the reaction kinetics. This type of reactor considers all the components as possible products, which is useful when there are many reactions between several components and the reaction kinetics is unknown. The operating temperature, pressure and O 2 to coal ratio are the key parameters
capture at Ashaka Cement Plant using Selexol is expected to be slightly higher than at a power plant, reason, basically due to lower economies of scale and the need to install FGD, NOx reduction and Dust control devices. Finally, both minimum and maximum capture cost, energy consumption and maximum annual cost per annum to be paid should be considered, hence this will lead to the best Cement Plant, putting into consideration, carbon price development and regulatory requirement during the plant’s lifetime.
To make a better use of the interactions between the CFPP and PCC systems and combine them together, the flue gas flowrate and steam flow rate to re-boiler are utilized as additional feedforward signals in the PCC and CFPP controller designs, respectively. Different from the conventional design approaches, which only send the measured flue gas flow rate signals at current sampling time to the PCC controllers [24, 30], a method for deep reinforcement integration and coordination of the two systems is proposed in this paper. The method makes full use of the prediction feature of MPC, that takes the current and future estimation of flue gas and re-boiler steam flow rates as respective feedforward signals in MPC_PCC and MPC_CFPP developments. The future coal mass flow rate is predicted by the MPC_CFPP, from which the future flue gas flow rate is estimated. The future steam flow rate to re-boiler can be predicted by the MPC_PCC at each sapling time. The working principle of the entire coordinated control system is shown in Fig. 1.
Since the first of dozen 370 MW units was commissioned in the Bełchatów Power Plant in 1982, a systematic research on power units reliability was initiated by the Institute of Electrical Power Engineering at Lodz Univer- sity of Technology. The principal target of analyses prepared yearly has been estimation of actual reliability measures of main generating devices of power units. Statistical data files of the successive years of the power plant operation have been systematically complemented and verified. The verification of statistical data consist in elimination of events which are not of random origin (i.e. actively influenced by operation and maintenance staff) and these, which were not qualified as break-downs only because there was enough ready-reserve power during failure.
Abstract—The objective of this study was to investigate the key factors for the quality of coal used in operating coal-firedpowerplants impacted by the geological origin, particularly with the case study of Indonesian Coal used in South Korea. Growing demand of power generation for commercial benefits and industrial uses, coal is the major source of power generation. Presently, South Korea is booming to manufacturing all commercial products throughout the world. So the power generation is most important not only for South Korea, but also throughout the world. The world-wide distribution of coal depends on the geologic impact which affects the type and the quality of raw coal. Since, South Korea imports majority of bituminous or sub-bituminous coal from Indonesia, we studied Indonesian coal provided by Hadong Thermal Power Site Division of Korea Southern Power Co., Ltd. The quality of the sample was analyzed by the geologic origin of the sample site which affects the quality. Additionally, due to serious environmental problems from coalcombustion waste dumping, recycling and recovery technology are necessary to prevent the landfill. The major advantage of this recycling technology is not preventing landfill and also recovery of critical rare earth elements and it is good scope for doing new research directions. Here, we presented some studies of rare earth elements associated with coal origin.
Our identified confounders associated with both coal capacity and lung cancer at the national level included adjustments for the appropriate latency period and strong temporality justifications for causal inference . However, residual and unmeasured confounders, such as national-level educational attainment or occupa- tional exposure, may exist; adding more parameters to our analysis would destabilize estimates and cause loss of statistical power. Potential misclassifications of me- teorological factor such as wind directions, and/or geo- graphical factors, cannot be adjusted in our model. Since neither the electricity matrix nor meteorological/geo- graphical factor is relevant to a country ’ s healthcare sys- tem, misclassification is non-differential and more likely biases toward the null. Potential misclassifications of lung cancer diagnosis must also be considered across countries even GBD study is the best available data we can obtain . The GBD study does not provide different types of lung cancer incidence for country-to-country comparison. Both adenocarcinoma  and squamous cell carcinoma [46, 47] of lung might have association with environmen- tal factors. Further studies focusing on different types of cancer and coal-firedpowerplants should be conducted.
Took 100ml of desulfurization wastewater after pretreatment, adjusted its pH value, added a certain amount of coagulant, started the mixer, stirred it in high-speed(about 300r/min) for 0.5min, stirred it in medium-speed(about 150r/min) for 5min, stirred it in low-speed(about 70r/min) for 10min, after 10min,added 1mL of PAM solution. Let the solution sit for a certain time, drained the supernatant with a 50mL injection tube, determined the water quality parameters of treated wastewater using single factor experiment method and orthogonal experiment method, the water quality parameters includes chemical oxygen demand (COD), turbidity, and studied on its flocculation performance.
Furthermore, lighter, volatile metals (alkali, transition, and heavy metals, e.g., Cu/Cr/Ni/Fe/V) can aid oxidative solvent degradation in post-combustioncaptureplants if these are carried over [17–19]. They can dissolve and catalyze oxidation, even at low concentrations, or take part directly in reactions—with both pathways affecting a range of alkanolamine solvents [19–22]. Volatile metals, present as strong anions have the potential to react with amine cations to form heat-stable salts, destroying the solvent. Transition (and heavy) metals tend to be concentrated in the flyash (rather than the coarser, bottom ash)  and submicron particulates (ultrafine or nanoparticles) can bypass the solid-phase separation devices to be carried over to the capture plant, where they build up. Moreover, biomass ash demonstrates much higher enrichment factors than coal ash for a number of metals, including Cu and Cr . Oxidative degradation is initiated by the presence of free radicals and thus the inclusion of redox reactive metal ions, in solid or gaseous (aerosol) form, may generate significant amounts of these, accelerating degradation rates . These can also cause corrosion in the system. Additionally, these metals have the potential to catalyze other reactions in the high-purity CO 2 stream. Although much is known about the ill effects that metal emissions can have, there is scant
motivates generator to build cleaner production facilities. Rosendahl  proves that allowances pricing through unconstrained market may decrease generator’s mitigation investment because of market externality. In reality, from 2005 to 2012, EU ETS induced carbon price fluctuated vigorously, which was the main problem of the mechanism [3, 12]. Meyer  and Zhao et al.  hold that price vibrating too much cannot encourage generator to invest in carbon capture and sequestration (CCS) because of risk consideration. Meanwhile, Alerola et al.  also give empirical evidences that EU ETS cannot support price high enough to motivate generator to abate CO 2 emission. It is necessary to supplement
When developing the two different models, it is clearly seen that BA-ELM model is very simple because its training only needs one iteration. The performance com- parison of the bootstrap aggregated neural networks and bootstrap aggregated ELM is shown in Table 1. The training CPU time of BA-ELM is about nine times lower than that of BA-NNs. The short training time of BA-ELM is due to the fact that each individual ELM is trained in one step without the need of gradient based iterative training. The verification time of BA-ELM is longer than that of BA-NN as the individual ELMs have more hidden neurons than the individual networks in BA-NN. The MSE value on the unseen validation data from BA-NNs is higher than that from BA-ELM. This could be due to the training of some neural networks in BA-NN might have been trapped in local minima or over fitted the noise. The results given in Table 1 demonstrate that BA-ELM is able to train faster and perform better than BA-NNs. The performance of one- step ahead predictions and multi-step ahead predictions of CO 2 production rate in BA-ELM and BA-NNs is indicated
power output. The calculated TIT and rotational speed are 946ºC and 69,727 rpm, respectively, which are very close to reference values given in Section 3.1 and in . Table 5 shows the base case MGT calculation results for both models, which are in good agreement with the manufacturer reference data . The small discrepancy in the electrical efficiency and fuel consumption is mainly due to power consumption of the auxiliaries such as buffer air pump and lubrication oil pump, which were not considered in the model. In addition, there might be a difference between the natural gas composition in this study and that used by the manufacturer. It is noteworthy that the difference in LHV values calculated by two models is mainly due to different property packages and reference values used by two software tools.