Abstract

A two stages process integration of high-gravity (Higee) rotating packed bed (RPB) and resin wafer electrodeionization (RW-EDI) technology was developed for CO2 mineralization, waste utilization and water reclamation. To stabilize and upgrade the properties of the municipal solid waste incineration fly ash (MSWI FA), accelerated carbonation was performed to convert calcium-bearing species into calcium carbonates via a Higee RPB. The direct and indirect carbonation process were consecutively operated via a RPB while the leachate (water washing liquid) from MSWI FA carbonation with high content of chloride ions was reclaimed via a RW-EDI process. In this study, the carbonation conversion of MSWI FA in direct carbonation using Higee process was evaluated along with CO2 capture capacity, CaCO3 formation and energy consumption. Several key factors including rotating packed bed and liquid-to-solid ratio (LSR) were evaluated through experimental design. In addition, the energy consumption and productivity of MSWI FA leachate using RW-EDI was evaluated. Results indicate that the carbonation conversion was increased as raising the rotating speed and lower LSR. The maximal carbonation conversion of 89.81 % was found at rotating speed of 1000 rpm and LSR of 10. To remove the residual calcium ions in the leachate, the indirect carbonation was conducted in a RPB. The outlet CO2 concentration, pH value, calcium ions concentration and conductivity of leachate were decreased as over reaction time. The maximal CO2 capture efficiency was found at the reaction time of 5 minutes. Furthermore, the results show that the relationship between energy consumption and productivity of MSWI FA leachate treatment via RW-EDI was negative correlation. The energy consumption of RW-EDI for MSWI FA leachate treatment was found to be 1.49–3.61 kWh/m3 with productivity of 12.82–17.09 L/hr/m2 . It suggested that the integrated HiG-EDI system offers the potential for an abundant source of CO2 capture, MSWI FA stabilization and fresh water from FA leachate treatment, which should be viewed as a crucial component in the portfolio of CO2 capture, waste stabilization and water reclamation.

Abstract

This paper presents a methodology to evaluate the whole system energy-economic-environmental performance and the economic viability of integrating new technology options such as heat pumps, energy storage units to an existing multi-vector energy system. The transition to a low carbon energy system would require that decisions to invest in new low carbon technology in local energy supply systems carefully consider the choice of technology as there are a plethora of technology options available with varying degrees of uncertainty to reach the same destination. The methodology is applied on a real campus multivector energy system to evaluate the whole system performance and economic viability of integrating heat pumps to its existing energy system that depends on gas fired CHP and gas boilers for its heat supply.

Abstract

Geographically diversified VRE portfolios can be used to smooth out the volatility of VRE output ramps. This study, using Taiwan as case study, developed efficient frontiers of optimal VRE portfolios to minimize the volatility for each possible level of total installed VRE capacity that can meet 10%, 20% and 30% of electricity demand. Our analysis shows that optimal portfolios are also beneficial to reduce the magnitude of extreme downward ramp events, which are sudden losses in VRE power outputs. We specifically investigated hourly extreme ramps that are expected to occur on average once-every-three-year. They are 13-30 % of each unit of installed VRE capacity for optimal VRE portfolios, which are significantly smaller than that (20-64%) for most individual VRE assets. This result helps to manage risks associated with extreme ramp events in power system operation. To capture the benefits associated with optimal portfolios, it is recommended for policy-makers to coordinate the investment and development of VRE assets across multiple locations.

Abstract

Small Island Developing States (SIDS) are afflicted by structural handicaps such as remoteness, small size and high dependence on international trade. They also share common energy challenges that jeopardize their ability to achieve a sustainable energy future. We identify factors that could potentially impact their respective energy systems such as energy import dependency and energy mix diversity. A composite index of energy vulnerability is constructed using a Multi-Layer Data Envelopment Analysis (MLDEA) approach based on eight energy indicators for 38 SIDS and other island territories. Reunion and Tuvalu make up the reference set of countries from which underperforming SIDS can benchmark best energy practices. Ultimately, this data-driven composite index of energy vulnerability can serve as useful tool for identifying priority areas that require immediate action. We recommend inter- and intra-regional cooperation between these territories based on a country clustering analysis.

Abstract

Concentrated Solar Power (CSP) plants are usually coupled with Thermal Energy Storage (TES) in order to increase the generation capacity and reduce energy output fluctuations and the levelized cost of the energy. In Direct Steam Generation (DSG) CSP plants, a popular TES option relies on steam accumulation. This conventional option, however, is constrained by temperature and pressure limits, and delivers saturated or slightly superheated steam at low pressure during discharge, which is undesirable for part-load turbine operation. However, steam accumulation can be integrated with sensible-heat storage in concrete to provide high-temperature superheated steam at higher pressures. The conventional steam accumulation option and the integrated concrete-steam option are presented, analysed and compared in this paper. The comparison shows that the integrated option provides more storage capacity by utilizing most of the available thermal power in the solar receiver. Further, the integrated option delivers higher power output with enhanced thermal efficiency for longer periods when the power plant is solely operating using the stored thermal energy. An application to the 50 MW Khi Solar One CSP plant, based on solar tower and in operation in South Africa, is proposed.

Abstract

This paper conducts a numerical study to investigate the Mine Water Heat Recovery (MWHR) system using a code developed in MATLAB. The system comprisestwo heat exchanger units, one located in mine water discharge region (Heat capturing unit) and another in mine intake air region (Heat delivery unit). Former captures heat energy from hot water at mine water outlet using a glycol closed-loop circuit and latter exchanges this captured heat with mine intake cold air. Thermal coupling between these two mentioned units is taken into account in the code. A typical underground mine in Canada is investigated as a case study to evaluate the feasibility of the system. In addition, to have a wider overview, a parametric study is conducted to investigate the impact of various parameters including mine intake air heating demand and mine intake air flow rate on energy savings.

Abstract

The mechanical characteristics of 304 stainless steel T-joint and lattice truss panel structure with pyramidal core were extensively investigated by the combinational methods of the experiments, finite element simulation and analytical model. The experimental results reveal that a T-joint with 2.25kW laser welding power, 2.5m/min welding speed and 5mm separation performs the better ultimate tensile load and strength ratio. The mechanical responses of T-joints are mainly dominated by elastic-plastic deformations. The laser welding reduces slightly the elasticity, ultimate tensile strength and fracture toughness of the structure. The joints present typical ductile fracture once the loads reach fracture strength. Under three-point bending test, the mechanical curve is divided into elastic, yield and failure region, and the deformation characterizes and failure modes are tension and shearing stress controlling. The results are verified by the FEM simulation.

Abstract

The economy of China is highly coal intensive. CO2 Capture, utilization, and Storage (CCUS) is now the only available technology that can cut up to 90% of CO2 emissions from power plants and large industrial processes fueled by coal or other fossil fuels. Without CCUS, the cost of meeting the anticipated long-term climate change mitigation objectives would be about 25% higher. For this reason, CCUS is recognized as the indispensable clean coal technologies in China. However, the progress of CCUS technology in the past several decades is rather behind that of the renewable energy, not only in China, but also in the world wide. The aim of this paper is to identify the critical gap interfering the deployment of CCUS technology from the level of whole CCUS chain, and then find the path for promoting CCUS development. In this paper, five CCUS cases with different combination of CO2 sources and sinks, which including the one combining high purity source in coal chemical production industry with enhanced of oil recovery, and another one combining coal fired power plants with saline aquifer storage, are evaluated. The performance of different case like energy penalty, the economic cost and the environmental emission are compared. The results indicate that the CCUS case with high purity resources shows significant advantages in the energy penalty and the cost. On the basis of this result, the breakpoint for development of low cost CCUS technologies is indicated, and the recommendations are suggested.

Abstract

A multitude of efforts towards low-carbon transportation development foster concentration strategies around reducing vehicular emissions. Extensive literature is looking for strategies linked to how the built environment might be improved to reduce GHGs together with vehicular transportation, which reveals the importance of coordinating the balance of high-density urban areas development for low-carbon transportation. In this research, we focus on the integrating both transit and development in TOD areas. We aim to contribute to constructing an interaction network between TOD areas, and combine the PoI data to provide a refined method for analyzing the stability of integrated development of urban functions and traffic intensification which could help provide strategies to vehicular emissions.

Abstract

Due to depleting fossil fuels, finding new and renewable energy resources becomes a strategic issue for the world. Although macroalgae has indigenous attractive, it does not play a key role in substitution for fossil fuels. Therefore, this work addresses the optimal design of macroalgae- based biofuel supply chain under economic objective to determine strategic level decision. It proposed mixed integer linear programing (MILP). the objective is minimizing total annual cost with regards to meet the fuel demand. Applicability of the proposed mathematical model is illustrated through a case study of south Korea. It is located in east Asia that is home of macroalgae.