Flue gas quench (FGQ) at advanced combined heat and power (CHP) plays a vital role by linking flue gas (FG) cleaning and wastewater treatment. In this paper, we have performed a detailed mass balance of pollutants in the flue gas and the process water with and without FGQ at a CHP plant. The results show that the system with FGQ puts less wastewater load (about 74 tonnes/day) together with less pollutant load on the municipal wastewater treatment plant (MWWTP) than the system without FGQ. Meanwhile, it results in fewer burdens on the external water use.
Ocean thermal energy has been identified as a good thermal source for electric power generation especially for offshore oil and gas platforms and island energy security. Organic Rankine Cycles (ORCs) are promising systems for conversion ocean thermal energy to electricity; however, the thermal efficiencies still need to be increased. In this work, a dual-pressure ORC is used to improve the thermal efficiency of a closed ocean thermal energy conversion (OTEC) power plant. The evaporation and condensation temperatures of the dual-pressure ORCs are optimized to maximize the net power out. Compared to single-pressure ORCs, the dual-pressure ORCs can reduce the warm seawater temperature drop about 2 °C and generate 28-29% more net power. The working fluid with a higher critical temperature has a lower flow rate for the optimal condition. R600 produces slight high power than the other selected working fluids.
China has launched lots of environmental policies to address the serious air pollution. The effectiveness of such kinds of policies are still in debate. Whether the policy makes a difference or not, this article argues that it highly depends on policy targets recognition. To take the motor vehicle restriction policy as an example, the target of the policy may not only focus on developing the air condition, but also other objectives. This on-hand article conducts a regression discontinuity design to test two goals of Zhengzhou city’s motor vehicle restrictions policy which are efficiency target (“help to complete the political assessment goal”) and legitimacy target (“help to achieve pollution control goal”). This article measures the former goal based on daily data and the latter one based on monthly data, both from Jan. 2016 to Dec. 2018. Air quality is selected by monthly air monitoring station, economic activities data is sorted from the official statistic website, and government action data is collected from the government documents by hand which we follow seriously and scientifically coding rules. Other factors, like climate influences, consumption and production behavior, are also controlled in the experiment. Regression results show that the restriction policy doesn’t make an obvious difference on developing the air quality before and after, but it does have statistically significant effect on helping the urban government to achieve the political assessment goal of the so-called “Qualified days”. The experiment also adjusts the bandwidth of the policy timing. The results obtained were highly robust across a variety of tests. What’s more, to make explanations on the restriction policy failure, this article collects the vehicle selling data and gasoline consumption data during the same period to test the policy spillover effect on consumer behavior. Results show that the driving restriction policy lead to an obvious otherwise slight increase on consumers’ behavior of buying a second car or using the alternative car. This study contributes to empirical evidence and add to a new case of researches on the air pollutants governance and policy evaluation.
Internal short circuit (ISC) plays an important role in lithium-ion battery safety accidents. However, the mechanism of how ISC triggers thermal runaway is still unclear yet. We implant the shape memory alloy device into jelly-roll to trigger ISC and analyze the thermal and electrical behaviors under different ISC types and SOC variance conditions. The ISC resistance is identified by using the no-salt battery based on the electrochemical impedance spectroscopy tests. The proposed resistance identification method benefits further ISC mechanism and modelling research.
Use of a cheap, non-edible feedstock would reduce the biodiesel production cost and make the process economically viable. This study investigated the production of fatty acid methyl ester (FAME) using both acid (sulfuric acid, H2SO4) and base (sodium hydroxide, NaOH) catalysts. Techno-economic analysis was performed to assess the commercial feasibilities of acidcatalysed biodiesel production from waste shark liver oil (WSLO) and alkali-catalysed biodiesel production from refined vegetable oil in Oman. Historically, the discarded WSLO was used to proof wooden boats, but now these applications are no longer required as modern boats are made of fiberglass. Hence,the excess WSLO derived from these discarded shark livers in the fishing industry could instead be utilised for biodiesel production. This would be environmentally beneficial as it converts a waste into a product. Aspen HYSYS-V9 was used to simulate both production types at plant capacity of 12,000 te/y and lifespan of 20 years. Net present values (NPVs) of US $34.8 and US $4.9 million were obtained for the acidcatalysed process using WSLO and the alkali-catalysed process using refined vegetable oil, respectively. The internal rate of return (IRR) was calculated to be 260% for the acid-catalysed process and 56% for the alkalicatalysed process. Sensitivity analysis was also conducted to show the effect of certain variables on the NPV of both biodiesel production types. It was concluded that the biodiesel selling price has more effect on the NPV than the glycerol variation price, whereas the triglyceride feedstock purchase prices have the largest influence on the NPV of the two processes.
This study involves the application of artificial neural network (ANN) as an intelligent approach to predict the output power of one alpha-type Stirling engine under some operating conditions. One ANN model had been developed based on experimental data from published literature. Output power as one of the performance indicators, was chosen as a response to input parameters, heat source temperature, engine speed and charging pressure. A multi-layer feed-forward network with a back-propagation algorithm had been proposed for such a prediction. The ANN model had been proven to be desirable in accuracy for predicting the output power by comparing the model results with experimental ones under the same operating conditions. This work would provide an effective approach based on ANN technique for solving complex design problems either with linear or nonlinear nature.
This study is part of an investigation on the influences of future energy demand and increased application of renewable resources on production planning of a regional energy system in the central part of Sweden. The study addresses the impacts of power supply from rooftop solar cells, increased application of heat pumps and penetration of electric passenger cars. Optimization results imply that use of heat pumps to replace district heating affects the demand side and reduces the heat production from energy plants. However, the power imports increase by 22%, compared with the reference system. By contrast, 100% penetration of electric vehicles in the transportation system only increases the power imports, without substantial effects on the energy plants performance.
Promoting clean heating in winter in the northern region is related to the warmth of the masses in the northern region and whether fog and haze can be reduced. On the basis of summarizing the current situation of heating in rural areas of northern China, this paper expounds the practical problems and basic needs of clean heating. Taking Shandong as the research object, this paper studies the applicability of different modes of clean heating technology in rural areas of North China.The author calculates the heat load demand during heating period, screens the suitable clean heating technology in Shandong area, and obtains the suitable technical path and application mode for rural clean heating in Shandong area.The technical feasibility, economic feasibility and environmental impact of different modes of clean heating, such as solar heating, gas heating and biomass pyrolysis multi-generation heating, are analyzed. The results show that under the existing economic and technological conditions, biomass pyrolysis polygeneration is suitable for clean heating in rural areas of Shandong Province, especially for demonstration and promotion of small centralized or decentralized heating in natural villages or new rural communities. This study provides a new way to solve the problem of clean heating in rural areas of northern China.
Hourly energy readings from heat billing meters are valuable data source for energy performance assessment of district heating substations and the buildings they serve. The quality of such analyses is bounded by the accuracy of the hourly readings. Thus, assessing the accuracy of the hourly heat meter readings is a necessary (but often overlooked) first step to ensure qualitative subsequent analyses. Due to often limited bandwidth capacity hourly readings are quantized before transmission, which can cause severe information loss. In this paper we study 266 Swedish heat meters and assess the quantization effect by information entropy ranking. Further, a detailed comparison is conducted with three heat meters with typically occurring quantization errors. Uncertainty due to the quantization effect is compared with the uncertainty due to typical accuracy of the meter instrumentation. A method to conflate information from both energy readings and energy calculated from flow and temperature readings is developed. The developed conflation method is shown to be able to decrease uncertainty for heat meters with severely quantized energy readings. However, it is concluded that a preferable approach is to work with the heat meter infrastructure to ensure future recorded readings holds high enough quality to be useful for energy performance assessments with hourly or subhourly readings.
In this work, aqueous pentaethylenehexamine (PEHA) was studied as a solvent for CO2 removal to produce purified bio-syngas from biomass gasification, but also as a first step towards negative carbon emissions applying carbon capture and storage (CCS) technologies. Capture of CO2 was tested both with synthetic gas (labscale) and real syngases from the pilot-scale gasifier fed with a wide range of forest-based biomasses. The results showed that the effects of the components other than CO2 and the impurities from the real syngas on the performance of PEHA for CO2 removal are negligible. Combined with previous research results from labtesting with pure CO2 absorption, the aqueous PEHA was shown to be a promising solvent for CO2 removal from syngas. PEHA was also tested as a biomass pre-treatment agent to improve gasification behavior, however, no significant improvement could be identified during the tests performed in this study.