• Energy Research
• 12. Responsible consumption close
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AbstractThe hydrothermal treatment (HT) has demonstrated the ability to improve fuel characteristics of biomass. On the other hand, the liquid by-product, which potentially contains solubilized nutrient, is being poorly utilized. This paper presents an investigation on HT of empty fruit bunch (EFB) on both solid and liquid product characteristics. In this work, the effects of HT on EFB were investigated at the HT temperatures of 100, 150, 180 and 220°C with the holding time of 30minutes. The results showed that HT can increase the carbon content, remove up to 55% of ash content from EFB, lowering the potassium and chlorine contents down to 0.84% and 0.18%, respectively. Moreover, maximum of 37% of nitrogen, 65% of potassium and less than 10% of phosphorus in EFB were dissolved into the liquid product which positively correlated with the HT temperature. These results demonstrate the possibility of employing HT for producing solid fuel as well as nutrient recovery from EFB.

Abstract Management of waste is a main concern and one of the most crucial issues in modern society. Effective waste management considers prevention, recycling, and handling of waste in such a way that most effectively protects human health and the environment. Energy recovery is one of the accepted options in managing solid waste. In the present paper, a waste-to-energy conversion plant utilizing refuse derived fuel (RDF) with appropriate combustion technology was proposed for a local municipality in Lampang, Thailand. Realistic waste quantity and composition were estimated. Mass and energy analyses as well as an economic feasibility survey were carried out to evaluate performance and benefits of the proposal. With up to 220 tons of RDF available daily, it was suggested that a power plant project between 5 to 13 MWe generation capacity may be developed. For a baseline case of 5 MWe, the project is economically feasible with tolerance to ± 50% fluctuation in total capital cost, electricity sale price and tipping fee.

Abstract In many industrial companies a significant proportion of their total energy use is for process heat resulting in the need for improving thermal energy efficiency. A common technique to improve efficiency is through process heat recovery. Pinch analysis is a key method for optimizing industrial heat recovery resulting in greater energy efficiency and profitability. The method also shows how energy conversion units such as heat pumps, combined heat and power systems or organic Rankine cycles (ORC) can be optimally integrated into a process. An ORC converts low temperature waste heat (e.g. 100-200°C) into electricity. However, the integration of an ORC requires a sound conceptual design to ensure proper integration. In this paper the importance and application of pinch analysis for integrating an ORC is presented. Pinch analysis plays a significant role in the development of a sound conceptual design as it identifies and quantifies the amount of waste heat as well as allows the determination of the streams most suitable for the ORC. The so called grand composite curve is used for the integration of an ORC to ensure the proper placement when considering the entire process. A properly integrated ORC that uses waste heat as a heat source must operate below the pinch point, i.e. the ORC takes heat from below the pinch point and converts a part of it to electricity and rejects the remaining heat to the environment. This methodology stresses improving the overall process energetic efficiency first through heat recovery before using (real) waste heat in an ORC. A novel industrial case study is presented to illustrate proper ORC integration showing the benefit energetically but limited financially under the given process and economic conditions.

Abstract The level of development of the energy sector plays an important role in other sectors of the economy as well as on the national economy in general. The energy sector must be sustainable and must be based on the use of energy-efficient technologies. Energy efficiency in sources of energy is one of the priorities of Latvia in the field of energy and one of the tasks of the energy strategy in the European Union. This article offers an innovative solution for increasing energy efficiency in sources of energy by using an environmentally friendly chimney. The proposed technology focuses on the reduction of heat loss from exhaust flue gases using flue gas cooling with supplied air. One of the characteristics of the system is related to the use of environmentally friendly plastic material for the chimney outer pipe. The article reflects the justification of the proposed solution, as well as the planned methodology for research.

Abstract The fossil fuels accomplish almost 80% of the world energy needs. The ever increasing exploitation of fossil fuels has led to environmental pollution, global climate change and health problems to living beings. Hence to meet the needs of the future energy and to mitigate the environmental pollution, it is critical to look for the alternate fuels. Global energy infrastructure in the future is believed to be accomplished by the energy generated from the low-cost renewable resources. Algae biomass has emerged as a promising biofuel source, as microalgae-based biofuels are biodegradable, renewable, and eco-friendly in comparison to fossil driven fuels. This study aims to examine the importance of microalgae as an alternative renewable energy source and evaluate the key challenges in the production of microalgae biofuel.

AbstractGlobal primary energy demand is growing, and is likely to continue growing during the next years. Energy projections made by the World Energy Council, the International Energy Agency (IEA) and the US Energy Information Administration give similar pictures of future energy requirements, mainly supplied by fossil fuels. Although it is expected that the share of the fossil fuels in the energy mix will decline in the future, the dominant role of fossil fuels will remain for decades to come, which entails large emissions of CO2 if new policy measures are not endorsed. Carbon Capture and Storage technologies (CCS) have the potential to reduce CO2 emissions into the atmosphere, providing by 2050 up to 20% of the CO2 reduction required to combat climate change.In this context, one of the current European initiatives in terms of R&D&D on Carbon Capture and Storage (CCS) and Clean Coal technologies (CCTs) is the Technology Development Centre for CO2 Capture and Storage, or es.CO2 Centre, which is supported by the Spanish Government through The Fundacion Ciudad de la Energia (CIUDEN). CIUDEN is a research and development institution created by the Spanish Administration in 2006 and fully conceived for collaborative technology development on CCS and CCTs. The es.CO2 Centre incorporates the world's most advanced equipment for the development of capture processes through oxycombustion based on two combustion technologies: Pulverized Coal (PC) and Circulating Fluidized Bed (CFB).Foster Wheeler is the technology provider of the 30 MWth oxy-CFB unit, which achieved first fire on coal in September 2011 and underwent initial oxy-mode commissioning in December 2011. This CFB unit design allows multiple fuels to be tested either under conventional combustion with air or under oxy-fuel conditions (Flexi-Burn® concept), and combines CFB's intrinsic advantages (fuel flexibility and low SOx and NOx emissions) with oxygen- firing for CCS.This paper focuses on initial operational experiences of CIUDEN's 30MWth oxy-CFB facility. During the preliminary tests in spring 2012, and the first test campaign in summer 2012, an extensive amount of operational data were acquired for four fuels and fuel mixtures. Results from first operational experiences are extremely promising. This oxy-CFB installation, which is the first of its class, will provide a real basis for the design and operation of flexible and competitive oxycombustion facilities at demonstration scale. Results achieved here aim to validate the design of a future 330 MWe supercritical Oxycombustion Power Station (OXY-CFB-300 Compostilla Project) intended to demonstrate CCS technology in commercial scale.

AbstractGlobal climate warming caused by emission of greenhouse gas including CO2 is one of serious problems nowadays. In an effort to mitigate CO2 emissions, one of most effectively clean energy plan is to produce power from coal using the integrated gasification combined cycle (IGCC). However, the cost of existing CO2 capture technologies is still too high. Utilization of large-solubility and low-cost absorbent for CO2 capture in IGCC can effectively reduce the electricity price increase caused by addition of CO2 removal unit. As it needs to trap CO2 before combustion under high pressure in IGCC absorption is considered to be a better choice.HPP (Hot Potash Process) uses aqueous solution of potassium carbonate as the absorbent. Compared to physical solvent absorption method Rectisol and Selexol, HPP has relatively low investment and relatively high CO2 recovery. Even in comparison with other chemical absorbent amine method HPP still has advantages as good chemical stability and low vapor pressure.In this paper several activators piperidine, piperozine, pyrazine, morpholine, imidazole, N-hydroxyethyl piperozine, Naminoethyl piperozine, AMP was tested respectively at 70 °C. As a result, piperidine activation works best, followed by N-(2-hydroxyethyl)piperazine, N-(2-aminoethyl) piperazine, 2-amino-2-methyl-1 -propanol and piperazine, pyrazine and imidazole is at its worst. Among them, N-(2-hydroxyethyl)piperazine is less volatile, more stable and suitable as the activator. Absorbing capacity and absorbing rate of CO2 in carbonate aqueous solution with HPZ increases by 5% or more than those with PZ.An improved HPP process is presented adopting the new activator. In this process two de-absorption two columns is designed operating at different pressure. This makes it possible to reuse the heat of condensation during high pressure de-sorption in reboiler of low pressure de-sorption. By preliminary calculating the novel process can save energy consumption obviously. The steam consumption, cooling water consumption and power consumption declines by 43.30%, 31.81% and 10.57%, respectively. It is expected to develop a low-cost technology for capture CO2 from IGCC in the future.

AbstractIn this paper, a dataset of 92,906 dwellings was analysed adopting data mining techniques for the classification of heating and domestic hot water primary energy demand and for the evaluation of the most influencing factors. The sample was classified in three energy demand categorical variables (Low, Medium, High) considering different geometrical and physical attributes. The output of the model made it possible to set reference threshold values among the physical variables. Moreover, high energy demand dwellings were analysed in depth using a k-means algorithm in order to evaluate the design variables which need to be considered in a refurbishment process.