Abstract

Research on upgrading of bio-oil in supercritical alcohols shows a potential to produce vehicle fuels from bio-crude. However, the separation of solvent alcohols and upgraded oil remains a problem. In this paper, biocrude derived from fast pyrolysis of rice husk was upgraded in supercritical CO2 with the catalysts of Pd, Ru, Pt (supported on activated carbon), in order to recycle the solvent from upgraded oil spontaneously. Results reveal that increase of reaction temperature promotes both esterification reaction and hydrogenation reaction, while increase of initial H2 pressure promotes the conversion of aldehydes, but decrease the conversion of phenols and sugars. On this basis, the production process of fast pyrolysis and supercritical CO2 upgrading was established and simulated with Aspen plus software. Through life cycle inventory analysis, the environmental impact of this process were studied, and then compared with upgrading in supercritical ethanol. The result shows weaknesses centered in the agricultural production and upgrading process. At last, the analytic hierarchy process is used to consider the weights of various environmental indicators to obtain a comprehensive LCA result. The final results display a slightly better environmental impact potential than that of ethanol.

Abstract

This paper proposes the use of a heavy ventilated wall to store natural energy and improve heating performance. An ideal numerical model was setup, and the thermal performance and annual heating contribution under different heating power, building insulation, airtightness and climates were explored by case studies. It is found that the ventilated wall with heat source has the potentials for creating a stable thermal environment, and also contributes to reducing building heating load. The initial findings can help engineers to develop design proposals for building envelops with an active heat source at the early design stage.

Abstract

Electric vehicles (EVs) have been viewed by many as a method to reduce greenhouse emissions, operate mobility efficiently, and decrease energy consumption. The limited driving range is a huge challenge to promote the popularization of EVs. The wireless charging lane can charge EV when it travels, thus can decrease the driving range anxiety of the driver. In this paper, we propose a new wireless charging scheme which combines the signalized intersection and partial wireless charging lane. We develop an eco-driving control strategy for EVs at intersections with wireless charging. The numerical results show that the wireless charging scheme with the eco-driving control strategy can increase the driving range and decrease the travel cost.

Abstract

Goal commitment is a critical construct in understanding the relationship between goals and behavioral performance in the field of energy conservation. However, little has been done to investigate goal commitment in relation to electricity saving performances in household goal-setting treatment. This paper seeks to re-contextualize the associations of goal commitment with electricity saving performance in households and provide meaningful discussion and explanation to the findings observed. A field experiment was conducted to investigate the effect of goal setting strategy on household electricity consumption in Singapore. In particular, interventions of assigned and self-set goal setting types were compared. Residents’ goal commitment was also accessed to understand the relationship between goals and electricity-saving performance. The results revealed a significant positive correlation between self-reported goal commitment and self-set goal choice. However, no significant relationship was found between self-set goal choice and electricity savings. It was also found that goal commitment has no significant relationship with electricity savings when goal difficulty was not a moderator, as in assigned goal group.

Abstract

An optimal planning method is proposed for power distribution system with energy storage systems (ESS) in this paper, in which the degradation and ancillary service revenue on frequency regulation of ESS are both considered, as well as the network configuration, siting and sizing for ESS and substation expansion. The problem is formulated as a mixed integer programming (MIP) one to optimize the overall planning cost, including investment and operation cost, power transaction cost, revenue from regulation services and degradation of ESS. In addition, the model co-optimizes charging/discharging of ESS to earn money from regulation services and prolong ESS’s lifetime simultaneously by adding a penalty term in the objectives, thus further benefiting the economy of the distribution system. A planning problem based on IEEE 33-bus system is tested to demonstrate the effectiveness of the proposed method.

Abstract

To further advance low NOx pulverized-coal (PC) ignition theory, guide the parameter design of PC burner of bias combustion technologies and enable the related numerical simulation work, combustion experiments for an Indonesian coal were conducted in a 250-kW pilotscale Bias Combustion Simulator (BCS); multiple research means of combustion temperatures and flame spectra were used. The effects of initial Pulverized Coal Concentration (PCC) on the standoff distance, ignition mode and continuous flame region of bias PC jets in a reducing atmosphere were investigated. The results indicate that with increasing initial PCC for bias PC jets in the experiments, the standoff distance gradually decreased, the peaks of subsequent combustion temperature and light emission intensity gradually increased, the continuous flame regions became gradually concentrated, the flame stability became gradually stronger, and the ignition characteristics gradually improved. The initial PCCs changed the ignition mode of bias PC jets; there was homogeneous– heterogeneous combined ignition mode at initial PCCs of 0.33 and 0.41kg/kg; there was homogeneous ignition mode at an initial PCC of 0.53kg/kg. At different initial PCCs, the continuous flame region of bias PC jets leant obviously in the direction of the fuel-rich jet.

Abstract

Increasing penetration rate of renewable energy in distribution network (DN) require effective measure for self-balancing. Considers the profit of multi-investors with distributed energy resources (DERs) in a district DN, this paper proposed an incentive-based optimal operation method. This is a win-win situation for both the utility grid and the investors of DERs. On the one hand, the demand fluctuation and reverse power flow is reduced to delay the investment of gird expansion; the other part is the multi-investors can benefit from the coordinated response process. The case study demonstrates the effectiveness of the proposed approach.

Abstract

The hybrid of amines is regarded as a promising alternative to MEA owing to its good performance on kinetics and thermodynamics for CO2 absorption. The primary/secondary amine can serve as absorption accelerator and the tertiary amine act as CO2 sinker and regeneration promoter. In this study, a novel hybrid comprising of N-methylcyclohexyamine (MCA) and N, Ndimethylcyclohexylamine (DMCA) was put forward. The absorption kinetics using DMCA-MCA for CO2 absorption was investigated in a wetted wall column. The results showed that the total mass transfer coefficient of DMCA-MCA approach 2.02×10-10 mol/cm2 ∙s∙Pa, which was 1.2-folder higher than 5M monoethanolamine (MEA) as the benchmark. Moreover, the CO2 absorption capacity of DMCA-MCA hybrid reached 3.94 mol/L, significantly higher than 2.70 mol/L of 5M MEA. The thermodynamics was evaluated in a high pressure reactor, implying that the total regeneration heat was 2.20 GJ/t CO2, which was much less than MEA (3.99 GJ/t CO2). The results can benefit for developing novel absorption technology with DMCA-MCA solvent with a rapider absorption rate, higher absorption capacity and lower heat duty for CO2 capture.

Abstract

Hydrate decomposition is an endothermic reaction. The exploitation effect is closely related to the heat transfer properties in hydrate deposits. Based on the results of experiment and simulation with depressurization (PD), depressurization combined with wellbore heating (DH) and huff and puff method (HP), this paper mainly studies the heat transfer from the boundaries (QB), the heat consumption by hydrate decomposition (QH), the heat absorption by the porous sand (QS), and the heat loss (QL) to optimize the production methods. The results show that a limited amount of QL is caused by the heat transferred to the water bath in HP. In addition, the heat transferred from the water bath can offset the QS, which is the main component of QL in HP. Thus, the best heat utilization is seen in this method. PD shows its obvious weakness in hydrate recovery duration, although it only uses the QB for hydrate decomposition. For DH, the amount of the lost heat is the largest among the three methods, and the majority of QL is caused by the heat from wellbore heating transferred to the ambient environment. Thus, the heat utilization in this method is the worst. For the optimization of the exploitation method, it is of great importance to decrease the heat transferred to the surrounding environment.

Abstract

Gas hydrate is an ideal alternative energy source with high energy density and low combustion pollution. Based on the different distribution of methane hydrate, free gas and free water, gas hydrate deposits can be classified into four classes (Class 1, 2, 3 and 4). TOUGH+HYDRATE was used to simulate the dissociation process of depressurization in gas and water excess Class 2 and 3 methane hydrate deposits. The initial state and production pressure selection were the same as the experimental results. The simulation results were compared with the experimental results. In water excess condition, gas production volume in simulation is 1/3 higher than that in experiment, except hydrate production under 2.0 and 2.3 MPa in Class 3 deposit. It was found that the minimum temperature in simulation is larger than that in experiment during depressurization in Class 2 and 3 methane hydrate deposits when gas is excess.