Environmental study of waste energy recovery by using exergy and economic analysis in a fluid catalytic cracking unit

Based on the Weather Research and Forecasting model and the Models-3 community multi-scale air quality model (WRF-CMAQ), this study analyzes the impacts of meteorological conditions and changes in air pollutant emissions on the heavy air pollution episode occurred over North China around the 2020 Spring Festival (January to Februray 2020). Regional reductions in air pollutant emissions required to eliminate the PM2.5 heavy pollution episode are also quantified. Our results found that meteorological conditions for the Beijing-Tianjin-Hebei and surrounding “2+26” cities are the worst during the heavy pollution episode around the 2020 Spring Festival as compared with two other typical heavy pollution episodes that occurred after 2015. However, because of the substantial reductions in air pollutant emissions in the “2+26” cities in recent years, and the 32% extra reduction in emissions during January to February 2020 compared with the baseline emission levels of the autumn and winter of 2019 to 2020, the maximum PM2.5 level during this heavy pollution episode around the 2020 Spring Festival was much lower than that in the other two typical episodes. Yet, these emission reductions are still not enough to eliminate regional heavy pollution episodes. Compared with the actual emission levels during January to February 2020, a 20% extra reduction in air pollutant emissions in the “2+26” cities (or a 45% extra reduction compared with baseline emission levels of the autumn and winter of 2019 to 2020) could help to generally eliminate regionwide severe pollution episodes, and avoid heavy pollution episodes that last three or more consecutive days in Beijing; a 40% extra reduction in emissions (or a 60% extra reduction compared with baseline emission levels of the autumn and winter of 2019 to 2020) could help to generally eliminate regionwide and continuous heavy pollution episodes. Our analysis finds that during the clean period after the heavy pollution episode around the 2020 Spring Festival, the regionwide heavy pollution episode would only occur with at least a 10-fold increase in air pollutant emissions.

Air pollutant emissions from coal-fired power plants in China over the past two decades

In China, as the major source of energy consumption and air pollutant emissions, the power industry is not only the principal force that bears the responsibility of national emission reduction targets but also a breakthrough that reflects the effectiveness of emission reduction. In this study, based on the integrated MARKAL-EFOM system (TIMES) model and scenario analysis method, a bottom-up energy system optimization model for the power industry was established, and four scenarios with different constraints were set up to predict and analyze the power demand and the energy consumption structure. Emission characteristics, emission reduction characteristics, and emission reduction cost of sulfur dioxide (SO2), nitrogen oxide (NOX), particulate matter 2.5 (PM2.5), and mercury (Hg) were quantitatively studied. Finally, for the environmentally friendly development and optimal adjustment of power production systems in China, the control path in the power industry that is conducive to the emission reduction of air pollutants was obtained, which is of great significance for the ultimate realization of climate friendliness. The results demonstrate that from 2020 to 2050, the power demand of the terminal departments will increase, with the composition significantly changed. The focus of power demand will change from industry to the service industry gradually. If no additional targeted emission reduction or adjustment policies are added in the power industry, the primary energy and air pollutant emissions will increase significantly, putting great pressure on resources and the environment. For the emission reduction of air pollutants, the promotion effect of emission reduction measures, such as the implementation and promotion of non-fossil fuels, is restricted. The power industry can introduce and maximize the best available technologies while optimizing the structure of energy consumption to realize efficient emission reduction of air pollutants and energy conservation. In 2030, emissions will reach peak values with reasonable emission reduction cost. This has the additional effect of abating energy consumption and preventing deterioration of the ecological environment, which is of profound significance for the ultimate realization of climate friendliness.

Water scarcity threatens human life and it is likely to be a main concern in the next century. In this work, a novel multigeneration system (MGS) is introduced and assessed with energy, exergy, and economic analyses. This MGS includes a gas cycle, multieffect distillation, an absorption refrigeration cycle, a heat recovery steam generator, and electrodialysis. Electrodialysis is integrated into this configuration to produce sodium hydroxide and hydrogen chloride from brine to prevent its release to the environment with harmful impacts. The other products are electricity, cooling, and demineralized water. For the evaluation of the proposed system, one computer code is provided in engineering equation solver software. For physical properties calculation, the library of this software is used. The MGS produces 614.7 GWh of electrical energy, 87.44 GWh of cooling, 12.47 million m3 of demineralized water, and 0.092 and 0.084 billion kg of sodium hydroxide and hydrogen chloride over a year. Energy and exergy evaluations demonstrate that the MGS energy and exergy efficiencies are 31.3% and 18.7%, respectively. The highest and lowest value of exergy destruction rate is associated with the combustion chamber and pump, respectively. The economic evaluation indicates that the net present value of this proposed system is 3.8 billion US$, while the internal rate of return and payback period, respectively, are 0.49 and 2.1 years.

AimSeveral papers have analysed the clinical benefits and safety of Virtual Fracture Clinics (VFCs). A significant increase in the use of Trauma and Orthopaedic (T&O) VFCs was seen during the COVID-19 pandemic. This study aims to investigate the social impact of VFCs on the travel burden and travel costs of T&O patients, as well as the potential environmental benefits in relation to fuel consumption and travel-related pollutant emissions.MethodAll patients referred for T&O VFC review from March 2020 to June 2020 were retrospectively analysed. The travel burden and environmental impacts of hypothetical face-to-face consultations were compared with these VFC reviews. The primary outcomes measured were patient travel time saved, patient travel distance saved, patient cost savings and reduction in air-pollutant emissions.ResultsOver a four-month period, 1359 VFC consultations were conducted. The average travel distance saved by VFC review was 88.6 kilometres (range 3.3-615), with an average of 73 minutes (range 9-390) of travel-time saved. Patients consumed, on average, 8.2 litres (range 0.3-57.8) less fuel and saved an average of €11.02 (range 0.41-76.59). The average reduction in air-pollutant vehicle emissions, including carbon dioxide, carbon monoxide, nitric oxides and volatile organic compounds was 20.3 kilograms (range 0.8-140.8), 517.3 grams (g) (range 19.3-3592.3), 38.1g (range 1.4-264.8) and 56.9g (range 2.1-395.2), respectively.ConclusionsVFCs reduce patient travel distance, travel time and travel costs. In addition, VFCs confer significant environmental benefits through reduced fuel consumption and reduction of harmful environmental emissions.

Due to the high amount of natural gas resources in Iran, the gas cycle as one of the main important power production system is used to produce electricity. The gas cycle has some disadvantages such as power consumption of air compressors, which is a major part of gas turbine electrical production and a considerable reduction in electrical power production by increasing the environment temperature due to a reduction in air density and constant volumetric airflow through a gas cycle. To overcome these weaknesses, several methods are applied such as cooling the inlet air of the system by different methods and integration heat recovery steam generator (HRSG) with the gas cycle. In this paper, using a heliostat solar receiver (HSR) in gas and combined cycles are investigated by energy, exergy, and economic analyses in Tehran city. The heliostat solar receiver is used to heat the pressurized exhaust air from the air compressor in gas and combined cycles. The key parameter of the three mentioned analyses was calculated and compared by writing computer code in MATLAB software. Results showed the use of HSR in gas and combined cycles increase the annual average energy efficiency from 28.4% and 48.5% to 44% and 76.5%, respectively. Additionally, for exergy efficiency, these increases are from 29.2% and 49.8% to 45.2% and 78.5%, respectively. However, from an economic point of view, adding the HRSG increases the payback period (PP) and it decreases the net present value (NPV) and internal rate of return (IRR).

Life-cycle assessment of greenhouse gas and air emissions of electric vehicles: A comparison between China and the U.S.

Low-carbon transport policy measures will contribute to greenhouse gas emission reductions, as well as improvements in air quality via air pollutant emission reductions. Here, we developed a regional transport energy model by integrating a transport demand model and an energy system model to explore the associated air pollutant emission reductions achieved by low-carbon transport initiatives when projecting a path towards carbon neutrality. Several scenarios were created to identify the effectiveness and feasibility of low-carbon strategies using the Avoid–Shift–Improve (A-S-I) framework including “Technology”, “Regulation”, “Information”, and “Economy” instruments. Significant reductions in air pollutant emissions alongside transport decarbonization in China could be realized by implementing policy measures to establish effective transport demand management, a modal shift in transport use, and technological improvements. In particular, the “Improve” strategy was more effective in delivering significant reductions in air pollutant emissions than were the “Avoid” and “Shift” strategies, but the policy effects of each A-S-I pillar varied greatly for different pollutants and across different regions. An air pollution reduction strategy for the transport sector should be designed in an integrated manner based on a series of different strategies and tools.

Significant reduction in air pollutant emissions from household cooking stoves by replacing raw solid fuels with their carbonized products

Experiment and optimization of a new kind once-through heat recovery steam generator (HRSG) based on analysis of exergy and economy

Multiplicity of steady states in an UOP FCC unit with high efficiency regenerator

According to the recent rise in oil prices, interest in FCC Unit (Fluid Catalytic Cracking Unit) energy recycling is increasing. Such FCC Unit is a facility which refining low-valued bunker C oil into high-valued gasoline. Pressure vessel that refines crude in FCC Unit needs various interpretation because it operates under high-temp and pressure. Our concern about this FCC Unit is increasing. Experiments about its safety is not enough. In this paper, whether FCC Unit has structural stability or not, we found out FEM(Finite Element Method) analysis after trying 3D modeling by using FCC Units condition of design and critical stress as a translating data. First, we researched the safety of structure applying external factors using the natural frequency. The structure is safe from modal analysis result, the first natural frequency is 13.614Hz , beyond the of the frequency range of the wind (0.001~8Hz) and earthquake (0.1~10Hz).

The need for an economic risk analysis model developed during the late 1960's and a generalized model with automatic sensitivity calculations was created in 1969. The original version of the Economic Risk Analysis System (E.R.A.S.), PROCESS, was not sophisticated enough to handle the complexities of bidding in federal lease sales in the Gulf of Mexico. As a result, a second option, Model-1, was developed in 1970. In 1976, a third model, Model-2, was designed to analyze the investment opportunities encountered in the Atlantic and Alaska. PROCESS and Model-1 have been used successfully since their implementation; Model-2 will be used as soon as leasing is resumed outside the Gulf of Mexico. Introduction An economic analysis system (EASY) was developed in 1960 go run on the IBM 7070 computer. This system was used primarily for the economic evaluation of oil and gas properties. EASY was expanded and converted to the IBM 360 in 1966. Through the years, the need for a more sophisticated model became apparent. The new model had to permit general economic studies and provide automatic sensitivity analysis to such factors provide automatic sensitivity analysis to such factors as price and cost variations. In 1969 this model was developed with the added capability of Monte Carlo Simulation. The Economic Risk Analysis System (E.R.A.S.) has been successfully accepted and used since its implementation. It offers three options:PROCESS - for general economic studiesModel-1 - for the evaluation of on-shore and Gulf of Mexico oil and gas leasesModel-2 - for the evaluation of Atlantic and off-shore Alaska oil and gas leases. STRUCTURE OF THE MODEL E.R.A.S., under any of its three versions, consists of thirty-five computer programs and subroutines The Main Program monitors the handling of the information submitted by the user. The data is selected and processed by a simulation model, which calculates processed by a simulation model, which calculates schedules of production, expenses, and investments. Three Economic Analysis Modules calculate the income, depreciation, depletion, royalties, taxes, cash flow, and profitability indicators. The Monte Carlo Simulation features permit the sampling of the basic information for repeated analyses, which are then statistically analyzed at the end of the run. Various plot programs display the results graphically. plot programs display the results graphically. The complete output consists of a best estimate economic analysis, an economic analysis based on the statistical mean values of the schedules produced by the simulation, a statistical summary, and twenty-two plots. plots. ECONOMIC ANALYSIS E.R.A.S. is basically a comprehensive economic analysis model programmed to process up to twenty-four schedules (production expanses, investments, etc.), six products, one optional income (non-depletable), five operating expenses, four optional expenditures (expensed, capitalized, or depleted according to requirement), salvage, salvage claimed (or working capital), tangible and intangible development costs, lease cancellation, dry holes, equity payments, and equipment purchased with property. The model performs a cash flow calculation and offers such options as price escalation, royalties override, production payments, joint interests and split joint interest, different tax options, options for automatic depreciation of any or all investments. The Profitability Index (internal rate of return), Percent Profitability Index (internal rate of return), Percent Payout, Payout Period, and Present Worth of the Net Payout, Payout Period, and Present Worth of the Net Cash are also provided. The report includes the schedules, an economic analysis summary, and the detailed economic calculations.

This paper presents a cost modeling approach and the economic feasibility for selected plant configurations operating under three modes: air gasification, mixed air-steam gasification, and steam gasification combined cycle solid oxide fuel cell (SOFC) systems. In this study, three cases of biomass gasification integrated SOFC without combined cycle (base case 1) are compared with biomass gasification integrated SOFC-gas turbine (GT) with heat recovery steam generator (HRSG) hybrid configuration (case 2) and biomass gasification integrated SOFC-steam turbine (ST) cycle (case 3) for biomass feed stock. The plant design cases of integrated biomass gasification processes, SOFC, and combined cycles are investigated primarily employing aspen plus™ flow sheeting models. Based on the mass and energy balance results of the system simulations, the economic model calculates the size and cost estimates for the plant configuration equipments. Detailed purchase cost estimations for each piece of equipments and the corresponding total bare module cost were established based on the bare module factor, and the total direct permanent investment were established. The calculated direct permanent investment was used for economic feasibility analysis of the cogeneration plant configuration. The economic feasibility decision parameters, such as purchase cost estimations, total specific plant cost per kW, the financial net present value (FNPV), internal rate of return, and benefit to cost ratio for the system configurations were compared for three design cases. The results shows that the cost of the steam gasification system is shown to be highest compared to the mixed air steam gasification system and air gasification system due to the higher hydrogen production. Other than the SOFC and gasification costs, a significant cost towards the heat exchangers is about 15% to 20% of the total equipment purchase cost. The specific plant cost for the air gasification varied from the 16 600 US$/kW to 19 200 US$/kWe. For the case of biomass gasification-integrated SOFC-GT configuration, the major cost portions are shared by the SOFC, HRSG, and gasifier. The HRSG equipment shared a cost portion of 25% to 30% for all the operating modes. The cost is decreased with a similar trend as that of steam, mixed air-steam and air gasification systems. For the case of biomass gasification integrated with SOFC-ST configuration, the total equipment purchase cost decreases at a rate of 15% to 20% for both mixed air steam and air gasification system. Plant specific cost for the steam gasification mode varied from 15 200 to 17 200 US $/kW which is significantly very high.

This paper has three main objectives: firstly, to provide quantitative information on the potential greenhouse gas and air pollutant emissions reductions resulting from a number of future road transport scenarios; secondly, to illustrate the emission reduction measures available to local transport planners; and thirdly, to highlight the potential for these measures to be integrated into strategies that deliver other transport priorities. The results are drawn from a case study of Norfolk in the UK. We conclude that while technology can play a large part in reducing emissions of air pollutants, demand management is crucial to the delivery of long term greenhouse gas emission reduction and ultimately of air pollutant emissions too.