Since the first pilot test of CO2 waterless fracturing in 2014, a complete system, including equipment, operation and liquid, has been formed. Twenty-three field tests proved the functions of CO2 waterless fracturing on reservoir energy storage, artificial fracture network and mixed-phase production increase. The effects lead to great water saving and CO2 storage. A unit volume of CO2 has the equivalent effect with 2.4 unit volumes of water-based fracturing liquid on oil production. The final storage rate of CO2 is 76.46%, 30% higher than that of CO2-EOR technology.
This paper presents a techno-economic evaluation of the electricity generation options available to meet electricity demand in three remote areas not interconnected to the main power grid of the Kingdom of Saudi Arabia (KSA). It considers two main alternatives: 1) extension of the main grid and 2) development of new generation resources in the isolated local grids. In the analysis, the electricity transmitted by the main grid is generated by oil-fired (or natural gas) combined cycle power plants (90%) and from PV and wind (10%) -consistent with KSA’s plans for 2023- while the local isolated grids would include a combination of PV, wind, diesel, oil, HFO and li-ion batteries.
Results show that under most scenarios of capital costs, fuel prices, and costs of air pollution, developing the isolated grids is a better alternative than extending the main grid.
Considerable attention has been given to utilize the redundant renewable energy with its increasing penetration in the overall energy system. The corresponding concept of “power to gas” is actively investigated by changing the power into hydrogen for using it later. Because of its benefit of efficiency and environmentally friendliness, hydrogen is obviously a promising energy source. On the other hand, it costs a lot to store and transport it in practice. It is necessary to transform it into hydrogen-containing materials that is cheap to store and deliver. Alternatively, this paper investigates the case of using ammonia. While the ammonia production processes have been already developed, using it as an energy carrier is a different issue. It should be evaluated in terms of various measures such as economic feasibility, safety, etc. Particularly, this paper investigates the techno-economic feasibility of power to ammonia technology. The overall ammonia production cost is estimated based on the process simulation by using the surplus electricity price. There is much to be done in addition to the current work for the implementation of P2G in practice. The insight obtained in this paper can be a good indicator for the implementation.
The characteristics of residential energy consumption and environmental emission in urban China was focused in this paper. For that, consumer expenditure items of urban residents (1997~2015) was reclassified into five categories i.e., Food, Residential energy use, Housing and household appliances, Transport and communication, Other goods and services. The expenditure consumer price indexes of new categories were calculated. We reclassified industrial sectors of Chinese environmentally extended input-output (CEEIO) accordingly. An Almost Ideal Demand System (AIDS) was employed to calculate price and expenditure elasticity of residential energy demand. The Economic Input-Output Environmental Life Cycle Assessment (EEIO-LCA) method was introduced to estimate cumulative energy consumption and environmental emissions per monetary unit considering the whole life cycle perspective. We found that during the period of 1997~2015, for each 1% increase in household income, there would be a 1.13% increase in energy use. The uncompensated demand price elasticity was -0.2096, while the compensated was -0.2565. The cumulative energy consumption and environmental emission intensities of each sectors show continued steady decline trends. Specifically, For each 10000 yuan of expenditures, energy consumption, CO2, nitrogen oxides, SO2, smoke and dust emission decreased from 2.9848tce, 26.2843t, 0.1005t, 0.0962t and 0.0677t in 1997 to 1.6161tce, 8.192t, 0.0182t, 0.0172t and 0.0087t in 2015 respectively, which declined at an average annual rate of 18.49%、32.2%、43.66%、43.42%、49.54% respectively. It means that the energy and environmental efficiency in Chinese urban residential sector has been improved dramatically for nearly two decades.
The highly energy requirement of rich amine solvent regeneration process is the biggest obstacle for the industrial application of amine-based CO2 capture technology. In this work, to reduce the heat duty of solvent regeneration, the novel composite materials zeolite Beta /SBA-15 (BS) with different zeolite Beta (β) content were synthesized by the hydrothermal method with β as the silicon source and were utilized to prepare Zr@BS and Fe-Zr@BS catalysts for amine regeneration. Experiments for CO2 stripping were performed using amines (monoethanolamine (MEA), Diethanolamine (DEA) and 2-(Diethylamino) ethanol (DEEA)) with an initial CO2 loading of 0.5 mol CO2/mol amine at 370.15 K. Additionally, various techniques including including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), N2 adsorption–desorption experiment, ammonia and CO2 temperature programmed desorption (NH3/CO2-TPD), and pyridine-adsorption infrared spectroscopy (Py-IR) were adopted to characterize and estimate the prepared catalysts. Also, the catalytic CO2 desorption performances of seven different catalysts (β, SBA-15, three BS catalysts, Zr@BS and Fe-Zr@BS) were investigated in terms of the cyclic capacity, desorption rate and energy consumption. The experimental results showed that the catalytic performance of BS better than the individual catalysts, and that Fe-Zr@BS can enhance the desorption factor by 212% and reduce the energy consumption by 33% compared to the blank run. Furthermore, the Fe-Zr@BS catalysts have no influence on the amine absorption performance in terms of the absorption rate and have the advantages of good stability and easy regeneration. Based on the results of characterization and experiments, the possible catalytic mechanism for bifunctional Fe-Zr@BS catalysts catalyzed amine regeneration for CO2 stripping were proposed and the reusability of the catalysts were also investigated.
Emerging technologies of Industry 4.0 have introduced novel ways of perceiving maintenance management, which has developed from being perceived as a “necessary evil” to become proactive with a holistic focusing on entire systems rather than single machines from Maintenance 3.0. In this context, the industry has begun to really appreciate the unique opportunities followed by system dynamics and simulation tools capabilities of representing the real world. However, maintenance management and performance are complex aspects of asset’s operation that is difficult to justify because of its multiple inherent trade-offs. Although the majority are unanimous when it comes to the expected impact maintenance plays on company profitability, this is in most cases challenging to determine and quantify. Moreover, relevant literature is considered as limited, especially with regards to impact simulation of Maintenance 4.0. Therefore, this paper focuses on the supportive function system dynamics, and modeling and simulation tools can be of help to assess behavior and predicting the future outcome of Maintenance 4.0 in the era of Industry 4.0. This includes developing a conceptualized model that enables simulating the future expected behavior i.e. (un)availability and cost by implementing such maintenance system. In this context, a centrifugal compressor with the function of exporting gas to Europe is applied as a case study.
Solid Oxide Fuel Cell (SOFC) has great scientific significance and market space as a green energy industry. The SOFC power generation system has the characteristics of slow dynamic response of the output power, so the lithium battery is used as an auxiliary power source to cooperate with the SOFC for power generation. In this paper, the 500W pure hydrogen solid oxide fuel cell system is modeled first. Then, the lithium battery state space model is built, and the second-order RC circuit equivalent model is selected to build the SOC estimation model and the SOH estimation model respectively. The Particle Filter (PF) algorithm is used to realize the joint estimation of SOC and SOH of lithium battery. Finally, the T-S fuzzy controller is designed for energy control. By controlling the output current of the lithium battery, the SOC is within a reasonable range in the process of coordinated power generation. In order to simulate the working condition of the hybrid energy system and test the feasibility of the control algorithm, this paper uses dSPACE to build a semi-physical simulation platform, and downloads the control algorithm to the control board to combine with the system model and electrical equipment for online simulation. The validity of the test algorithm is verified by the irregular load power variation, the problem of slow response of SOFC power tracking is solved, and the protection of lithium battery SOC is realized.
Minimizing cost and greenhouse gas (GHG) emissions associated with the transport of biomass feedstocks are a major focus in sustainable bioenergy production. The issue of determining appropriate candidate sites for large green-field bioenergy plants and subsequently choosing between these site options continues to involve complex decision-making processes. This paper reports on a geographical information system (GIS) based optimization model developed to identify optimal sites that minimize the biomass delivery costs and associated GHG emissions under different biomass supply scenarios. The model used extended GIS-based Fuzzy multi-criteria methods to identify candidate sites and location-allocation analysis to identify optimal energy plant locations. The model was configured to investigate sugarcane waste for bioelectricity production in Queensland, Australia. Results for the siting of bioelectricity generation capacity in Queensland identified optimally located plants with installed capacity ranges from 57 MW to 185 MW and average transportation distances of 27 km to 64 Km. The Burdekin cane growing region was identified as the most favoured location when considering feedstock transport costs and associated GHG emissions.
With the growing threat of global climate change, energy savings and CO2 emissions reduction have become a major long-term issue faced by China. For a more scientific analysis of energy savings and emissions reduction data of China, a modified logarithmic mean Divisia index (LMDI) approach is adopted. The modifications and the theoretical model of the approach are introduced in this paper. Based on China’s economic development and energy consumption data during the 12th Five-Year-Plan period, quantitative assessment of effects of the energy savings and emissions reduction in the four key areas (namely energy conversion efficiency improvement, energy utilization efficiency improvement, primary energy mix adjustment and industrial structure adjustment) is carried out. The results and laws of energy savings and emissions reduction in the above areas during the 12th Five-Year-Plan period are summarized. Finally, combined with historical analysis and current situations, some suggestions for China’s future work in the field of energy savings and emissions reduction are proposed.
Substantial efforts have been made to develop low global warming potential (GWP) refrigerants in the last decade. Many studies indicate that R1234yf has similar thermodynamic properties to R134a but much lower GWP value, suggesting the opportunity of utilizing R1234yf as a substitute of R134a due to its advantages of a very low 100-year global warming potential value of 4, zero ozone depletion potential and excellent life cycle climate performance. Nevertheless, very limited studies have been conducted in the past years related to the flow condensation heat transfer of this refrigerant. The purpose of this study is to probe the condensation heat transfer and pressure drop characteristics of R1234yf in a horizontal circular minitube with an inner diameter of 4 mm. The validation of the numerical model showed that the predictions agreed well with measured results from the literature of Yang et al., and suitably simulated the development of two-phase flow patterns along the channel. We hence extended the computational fluid dynamics (CFD) simulations to assess the heat transfer and frictional characteristics of straight and converging condensed minitubes for R1234yf refrigerant at varied operating conditions of mass flux, heat flux and vapor quality, respectively.