Captive Power Plant Research Articles

Effect of gaseous agents on co-combustion characteristics of sewage sludge and coal

Co-combustion of sewage sludge and coal is a feasible way to seek energy and reduce environmental pollution. Oxy-fuel combustion is considered as an advanced technology to raise energy efficiency and improve CO2 capture in power plants. Thermochemical characteristics during co-combustion of sewage sludge and anthracite coal in air and oxy-fuel atmosphere were investigated via thermogravimetric analysis method. The co-combustion experiment was prepared into four mixing ratios at different heating rates in air and O2/CO2 atmosphere with 21% and 30% oxygen concentrations. The results showed that the ignition and burnout performance of anthracite coal could be improved by addition of sewage sludge. The comprehensive property index of blends at heating rate of 50 ℃/min were nearly 3 times more than those at heating rate of 20 ℃/min. The lower burnout temperature and elevated ignition temperature, maximum mass loss rate, comprehensive property index, and activation energy samples can be observed in 21%O2/79%CO2 atmosphere when compared with air atmosphere. With increasing oxygen concentration from 21% to 30%, ignition temperature and burnout temperature of samples were decreased, while maximum mass loss rate and comprehensive property index were increased. The activation energies of samples at heating rate of 20 ℃/min were decreased, but increased at heating rate of 50 ℃/min. These findings can provide new insights for further investigation on co-combustion of coal and sewage sludge.

Captive power, market access and macroeconomic performance: Reforming the Bangladesh electricity sector

Integrating the captive capacity with the on-grid supply has been advocated as a way to improve resource utilization in the electricity market in developing and emerging countries. Despite many countries granting Captive Power Plants (CPPs) access to the grid, integration may still be hindered by other barriers to entry. In Bangladesh, CPPs are required to sell their electricity surplus, but there is no evidence of trading with the national grid, mostly due to high connectivity costs. In this paper we develop and estimate a fit-for-purpose Dynamic Stochastic General Equilibrium (DSGE) model to examine the effects of the Bangladeshi CPPs connecting to the national grid and selling their surplus at regulated prices. The model parameters are set through a combination of calibration and Bayesian estimation. We find that if CPPs are connected to the national grid, steady-state industrial output, GDP, and household consumption decrease due to pre-existing energy price distortions. These results support the second-best theory, which implies that merely connecting the CPPs to the national grid without firstly removing market distortions can lead to economically inefficient outcomes. Instead, government should first consider alternative reforms such as phasing out subsidized tariffs and enabling a competitive market environment.

Water-energy-carbon nexus: A life cycle assessment of post-combustion carbon capture technology from power plant level

Carbon capture and storage (CCS) technology is widely regarded as an important strategy to limit CO2 emissions from point sources, especially for coal-fired power plants. However, current CO2 capture technologies are energy-intensive and require substantial cooling capacities. The extensive deployment of CCS technology increases the energy and water stress in power sectors. This study considers a plant level nexus approach to assess the relationship between water, energy consumption, and CO2 emissions of four types of available post-combustion carbon capture power plants from life cycle perspective. It is found that the integration of CCS translates into an increase in life cycle primary energy demand (PED) by 21–46% and water resources depletion by 59–95% compared with the reference power plant with wet cooling tower system, where the membrane-based system exhibits the best performance. However, the life cycle GHG reduction rate reduced to 65%–70% at 90% capture rate. The life cycle energy and water cost of GHG mitigation were quantified as 3.06–7.32 kJ/kg CO2-eq and 1.72–3.00 kg/CO2-eq, respectively, demonstrating the presence of sharp trade-offs between GHG reductions and energy demand as well as water consumptions for carbon capture technologies.

Application of System Dynamic Modelling for Evaluation of CO2 Emissions and Expenditure for Captive Power Generation Scenarios in the Cement Industry

Cement manufacturing is an emission-intensive process. The cement industry is responsible for 8% of the global CO2 emissions, and produces a ton of cement uses up to 102 kWh of electrical energy, leading to a significant amount of indirect emissions depending on the emission intensity of the electricity source. Captive power generation can be potentially utilised as a mitigation approach to reduce emissions and as well as expenditure on electricity tariffs. In this study, a system dynamic simulation model is built to evaluate the impact of captive power generation on a cement plant’s net emissions and expenditure through electricity use, under different scenarios for carbon-tax, grid emission factor, and electricity tariffs. The model is then utilised to simulate a reference plant under realistic scenarios designed based on the conditions in Germany and United Arab Emirates. Furthermore, the model is utilised to calculate the payback period of investments on captive power plants under different carbon tax scenarios. The study concludes that a carbon tax policy on emissions through electricity utilisation could have an impact on incentivising the use of captive power generation and would lead to fewer emissions and expenditure during the cement plant’s lifetime.

China's retrofitting measures in coal-fired power plants bring significant mercury-related health benefits

Summary China has implemented retrofitting measures in coal-fired power plants (CFPPs) to reduce air pollution through small unit shutdown, the installation of air pollution control devices (APCDs), and power generation efficiency improvement. The reductions in highly toxic Hg emissions and their related health impacts by these measures remain poorly understood. Here, we evaluated the health benefits of reduced Hg emissions via retrofitting measures during China's 12th Five-Year Plan (2011–2015) by combining plant-level Hg emission inventories with the China Hg Risk-Source-Tracking Model. We found that the measures reduced Hg emissions by 23.5 tons (approximately 1/5 of that from CFPPs in 2010), preventing 30,484.77 total points of intelligence quotient decrement and 114 deaths between 2011 and 2015. These benefits were dominated by CFPP shutdowns and APCD installations, and nearly 50% of provincial health benefits were attributable to Hg reductions in other regions. We suggest that Hg control strategies should consider various factors, such as CFPP location, population density, and trade-offs between reductions in total Hg and in Hg2+.

Polyvinylamine-Based Facilitated Transport Membranes for Post-Combustion CO2 Capture: Challenges and Perspectives from Materials to Processes

Carbon dioxide (CO 2 ) capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency, relatively low cost, and environmental impact. Polyvinylamine (PVAm)-based facilitated transport (FT) membranes were developed in the last decade for CO 2 capture. This work discusses the challenges of applying PVAm-based FT membranes from materials to processes for post-combustion CO 2 capture in power plants and cement factories. Experiences learned from a pilot demonstration system can be used to guide the design of other membranes for CO 2 capture. The importance of module and process design is emphasized in the achievement of a high-performance membrane system. Moreover, the results from process simulation and cost estimation indicate that a three-stage membrane system is feasible for achieving a high CO 2 purity of 95 vol%. The specific CO 2 capture cost was found to significantly depend on the required CO 2 capture ratio, and a moderate CO 2 capture ratio of 50% presented a cost of 63.7 USD per tonne CO 2 captured. Thus, FT membrane systems were found to be more competitive for partial CO 2 capture.

Molten shell-activated, high-performance, un-doped Li4SiO4 for high-temperature CO2 capture at low CO2 concentrations

Lithium orthosilicate (Li4SiO4) represents a potential class of high-temperature sorbents for CO2 capture in power plants and sorption enhanced methane reforming to produce H2. However, conventional wisdom suggests that pure Li4SiO4 should have extremely slow sorption kinetics at realistic low CO2 concentrations. Here, we report the opposite result: using a simple and cost-effective glucose-based mild combustion procedure, an unusually efficient and pure form of Li4SiO4 (MC-0.6) was synthesized to achieve a maximum uptake capacity of 35.0 wt% at 580 °C for CO2 concentrations under 15 vol% and maintained this capacity over multiple cycles. The characterization results showed that highly porous nano-agglomerate-like (50–100 nm) morphologies were apparent and ensured a rapid surface-sorption of CO2. In this process, a macroporous nano-sized Li2SiO3 cover on the melt layer of Li2CO3 was identified for the first time. This special structure appeared to accelerate the transportation of CO2 and the diffusion of Li+ and O2− through a molten layer enhancing contact with CO2. Thus, the sample MC-0.6 reduced both the surface-sorption and diffusion kinetics dependence on low CO2 concentrations. Rather than use traditional approaches (controlled morphologies combined with doping), we have demonstrated that the slow kinetics can be overcome simply by a controlled morphologies strategy, which opens up a new direction for the synthesis of high-performance Li4SiO4 sorbents.

Agro-industrial residue gasification feasibility in captive power plants: A South-Asian case study

The objective of this study is to build knowledge on the potential of agro-industrial residue gasification (AIRG) for use in captive power generation through a comprehensive case study. In order to evaluate the economic viability, key performance indicators, such as net present value (NPV), levelized cost of electricity (LCOE), and operating costs etc. are studied. The major textile industry located in the Raiwind area of Punjab province of Pakistan has been selected. The effect and variations of the capacity factor has also been studied coupled with the levelized cost of electricity. The agricultural residue as feedstock to the gasifier is rice husk that is the abundantly available in South Asia. Furthermore, the impact of government subsidies on natural gas is also under the scope of the study. The agro-industrial residue gasification system is found to be a potential alternative to furnace oil (FO) or gas-based captive power plants (CPPs). The results of residue-based gasification system imply a large potential when comparing the cost of electricity with national grid electricity during the peak hours. Therefore, the proposed gasification system offers economic incentives when the textile industry potentially utilizes gasification-based electricity during peak hours and national grid electricity during off-peak hours.

Feasibility of solar-assisted CO2 capture power plant with flexible operation: A case study in China

High energy penalty of solvent regeneration process is one of the main technical obstacles hindering the commercial application of amine-based absorption CO2 capture. It leads to 9–12% of efficiency reduction in power plants. Consequently, integrating solar energy to assist solvent regeneration for post-combustion CO2 capture (PCC) has shown potential to compensate for the efficiency penalty in power plants. Owing to the intrinsic intermittence and fluctuation of solar energy, it is expected that solar-assisted post-combustion CO2 capture (SPCC) power plants would operate flexibly to optimize its techno-economic performance. This paper explores the feasibility of solar-assisted carbon capture power plant with flexible operation in terms of net profits and CO2 emissions, using optimization modelling based on the Chinese electricity and carbon trading markets. This assessment was conducted under dynamic operation of the power plant. The operational status of the carbon capture system and solar thermal system were varied. Results indicate that compared to the conventional carbon capture plant, the cumulative profit of flexible solar-assisted carbon capture plant increased by nearly 50% in a selected typical month, whilst exhibiting around 25% ructions in cumulative CO2 emissions. Importantly, the economic performance of a solar-assisted carbon capture power plant is quite sensitive to grid-on electricity tariffs, subsidies for solar derived electricity, and to the carbon emissions allowance of the carbon market.

Environment-friendly and economical scheduling optimization for integrated energy system considering power-to-gas technology and carbon capture power plant

To mitigate global warming, CO2 emission reduction has become an urgent issue in the energy sector. In China, coal-to-gas, carbon capture and renewable energy utilization are important measures available among various low-carbon plans. However, inadequate gas supply, unclear utilization methods of captured CO2, and curtailment of excessive wind and solar power have hampered the effective implementation of the above measures. To solve this issue, this paper presents a coupling model considering power to gas (P2G) technology and carbon capture power plants (CCPP), and extends it into an integrated energy system (IES) including electricity, thermal and gas, then proposes an economic and environment-friendly scheduling model at a high wind power penetration level. Through the coupling of CCPP and P2G in IES, most of CO2 emitted by the system can be captured and sent to the P2G facility to produce synthesized gas, which provides a new idea of utilizing CO2 rather than storage. The synthetic gas can be provided to the system to reduce the external gas dependency. In addition, the simulation results also show that the ability of the system to absorb renewable energy is significantly enhanced with the presence of CCPP and P2G.

A high‐efficiency novel IGCC‐OTM carbon capture power plant design

AbstractCoal power plants play an important role in supplying affordable and reliable electricity. It is necessary to develop high‐efficiency and low‐cost carbon capture (CC) technologies to mitigate the associated global warming. Using H2S‐tolerant oxygen transport membranes (OTMs) for hydrogen production and CO2 separation can significantly reduce the energy penalty of CC in integrated gasification combined cycle (IGCC) power plants. We carried out system‐level analysis to investigate a novel IGCC‐CC power plant design using OTMs. We studied the impacts of various operating parameters on the overall efficiency and energy penalty. This novel IGCC‐OTM system has an overall efficiency 3.2%‐point lower than the same system without CC, much lower than the IGCC with water‐gas shift reactors and acid gas removal units (IGCC‐WGS) of 6.8%‐point drop. The specific primary energy consumption for CO2 avoided (SPECCA) of this novel technology is 1.08 MJ kgCO2−1, which is 59.4% lower than that of the IGCC‐WGS.

Analysis of the status and key technical issues of self-provided power plants in the future comprehensive energy application field

Many problems have been exposed in the development of the self-provided power plants, how to reform the self-provided power plants is very important. The construction of a comprehensive energy system covering self-provided power plants has become a new reference idea, which can guide the development of self-provided power plants in the direction of comprehensive energy. This article first introduces the development status of self-provided power plants and the concept of integrated energy system in detail, then analyses the potential relationship between self-provided power plants and integrated energy systems based on the characteristics of self-provided power plants, and then introduces three main applications of the self-provided power plants in the field of integrated energy applications in the future, and finally put forward the main problems related to the smart development of captive power plants and give some relevant suggestions.

Privacy-preserving decentralized power system economic dispatch considering carbon capture power plants and carbon emission trading scheme via over-relaxed ADMM

This paper proposes a decentralized power system economic dispatch (DPSED) model considering carbon capture power plants (CCPPs) and carbon emission trading scheme (CETS) under a low-carbon economy. First, CETS is introduced and analyzed, and a time-varying carbon emission quota allocation method is proposed. The centralized power system economic dispatch model (CPSED) under a low-carbon economy is established with the objective function to minimize the total operation cost in which CCPPs are introduced that can capture CO2 to reduce carbon emission trading cost. Then, the centralized economic dispatch problem is reformulated into a decentralized model. It is composed of a set of sub-problems in individual areas that can preserve privacy and be solved independently. The alternating direction method of multipliers (ADMM) algorithm is employed to solve the decentralized optimization model, reducing the amount of exchanged information and preserving the privacy of information shared among participating areas. Moreover, the over-relaxed ADMM algorithm is further adopted to accelerate the convergence. Finally, case studies are performed on a 6-bus system and an IEEE 118-bus system to validate the effectiveness of the proposed model and algorithm. Numerical results demonstrate that CCPPs could reduce carbon emissions, help wind power utilization, and achieve economic operation.

Solar-assisted CO2 capture with amine and ammonia-based chemical absorption：A comparative study

Intensive energy penalty caused by CO2 separation process is a critical obstacle for retrofitting power plant with carbon capture technology. Therefore, the concept of utilizing solar energy to assist solvent regeneration for post-combustion carbon capture power plant is proposed recently as a promising pathway to compensate the efficiency reduction derived from CO2 capture process. However, the feasibility of solar-assisted post-combustion technologies largely depends on the types of CO2 absorbent, categories of solar thermal collectors, areas of solar field, and the integration of thermal energy storage system. Therefore, this paper conducts a comparative analysis on monoethanolamine-based and NH3-based so-larassisted post-combustion power plants employing two types of solar collectors, i.e the vacuum tube and the parabolic through collector, with climate data of Tianjin City, China. Levelized costs of electricity and cost of CO2 removed are comparatively studied for both solar-assisted post-combustion configurations. Results show that the proposed solar-assisted post-combustion configurations are economically viable when the price of vacuum tube is lower than 86.64 $/m2 and 117.29 $/m2 for the monoethanolamine-based and NH3-based solar-assisted post-combustion power plant, respectively. Meanwhile, the price of parabolic through collector should be less than 111.12 $/m2 for the monoethanolamine-based and 114.51 $/m2 for the NH3-based solar-assisted post-combustion power plant. It is indicated that employing the vacuum tube for chilled NH3-based solar-assisted post-combustion power plant offers a promising approach to reduce the energy penalty with attractive economic performance.

Carbon Tax and Trading Price on Power Plant with Carbon Capture and Storage under Incentive Regulation Theory

This paper investigates how the government can develop subsidies or tax policies to incent power plants to effectively carry out carbon capture to reduce carbon emissions. According to the government’s incentive model for carbon capture power plants, the regulation mechanism is developed when government controls carbon emission. When regional or national carbon emission quota is tense, significant effect can be obtained when regulators make regulations to take off low efficiency power plants. In addition, it is verified that the regulators should not blindly pursue a reduction in carbon emissions regardless of the cost. Therefore, regulators need to pay more attention to control the costs of carbon capture equipment and technology. Finally, by parametric and numerical analyses, the conditions of the power plant to maximize corporate surplus are further studied.

Technical assessment of captive solar power plant: A case study of Senai airport, Malaysia

Solar PV system in the airport environment is a relatively new application. Unlike land-based solar systems, the site selection for the airport-based PV power plant is a complicated process and lacks proper methodology. The objective of this work was to develop a general sitting procedure for an airport-based solar PV system and identify ideal sites for solar farms in Senai International airport, Malaysia. Feasible sites were selected with due consideration to airport and aviation compatibility constraints. Next, suitability of such selected sites is assessed based on environmental impact and proximity to electrical infrastructure. Using glare prediction software, the adherence to FAA’s solar interim policy is assessed. Eleven (11) sites which lie within the airport are chosen for the study. The duration of glare from sites 2, 3, 4, 6 were 1125, 4724, 3805, 1125 min receptively. As a result, design parameters are changed for these sites. The results of the study showed that the solar PV potential and theoretical energy generation from the selected sites of the airport were 12.50 MW and 16,745 MWh respectively. The knowledge on the suitability of sites and prior glare assessment increases the level of confidence to airport stakeholders and project developers.

Combining Private and Public Resources: Captive Power Plants and Electricity Sector Development in Bangladesh

ABSTRACT Developing economies need to efficiently utilize both public and private resources to develop their energy sectors. The opportunity cost of failing to do so is high. This article uses a Dynamic Stochastic General Equilibrium (DSGE) approach to assess the integration of the Captive Power Plants (CPPs) in the power sector of Bangladesh. We find that if Bangladesh shut down the CPPs, the long-run industrial output and GDP would fall by 1.5% and 1.2%, respectively. The Impulse Response Functions (IRFs) show that the Bangladesh economy would be more vulnerable to oil price shocks without CPPs. In order to minimize distortion in the energy markets, the government could instead consider alternative reforms such as promoting the use of efficient production technologies or the replacement of fossil fuels with renewable energy sources.

R&D Efforts of CSIR-IMMT Toward Solving Some Issues Related to Aluminum Production

Due to the rapid increase in aluminum production from high-grade bauxite ores, such reserves are fast depleting. Determining cost-effective processes for the treatment of low-grade bauxitic ores, utilization of different wastes and byproducts of aluminum industries, and improvement in the extraction process steps are some of the pertinent issues. Red mud, i.e., bauxite residue, is a serious threat to the environment that needs serious attention for its end use. Another issue is the effective utilization of fly ash generated in the captive power plant. This presentation covers some of the R&D efforts made by CSIR-IMMT such as (1) bauxite beneficiation process to remove reactive silica and iron minerals, (2) recovery of Al2O3 and other value-added products from fly ash, (3) utilization of bauxite residue to manufacture of bricks, (4) producing boehmite and gibbsite from Bayer’s liquor by means of organic additives, and (5) producing value-added Al-based chemicals from Al dross.

Operating Assessment of Local Power Grid Development Considered Captive Power Plant and Expanding Structure

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

Research on Energy Management Strategy of Captive Power Plant Based on Hybrid Method

Research on Energy Management Strategy of Captive Power Plant Based on Hybrid Method