Greenhouse Impact Due to the Use of Combustible Fuels: Life Cycle Viewpoint and Relative Radiative Forcing Commitment

Extensive information on the greenhouse impacts of various human actions is important in developing effective climate change mitigation strategies. The greenhouse impacts of combustible fuels consist not only of combustion emissions but also of emissions from the fuel production chain and possible effects on the ecosystem carbon storages. It is important to be able to assess the combined, total effect of these different emissions and to express the results in a comprehensive way. In this study, a new concept called relative radiative forcing commitment (RRFC) is presented and applied to depict the greenhouse impact of some combustible fuels currently used in Finland. RRFC is a ratio that accounts for the energy absorbed in the Earth system due to changes in greenhouse gas concentrations (production and combustion of fuel) compared to the energy released in the combustion of fuel. RRFC can also be expressed as a function of time in order to give a dynamic cumulative picture on the caused effect. Varying time horizons can be studied separately, as is the case when studying the effects of different climate policies on varying time scales. The RRFC for coal for 100 years is about 170, which means that in 100 years 170 times more energy is absorbed in the atmosphere due to the emissions of coal combustion activity than is released in combustion itself. RRFC values of the other studied fuel production chains varied from about 30 (forest residues fuel) to 190 (peat fuel) for the 100-year study period. The length of the studied time horizon had an impact on the RRFC values and, to some extent, on the relative positions of various fuels.     

广东省火电厂烟气脱硫装置的经济技术分析

简要介绍了广东省7个火电厂现有的5种烟气脱硫技术装置：海水脱硫、荷电干式烟气脱硫、湿式石灰石／石膏法烟气脱硫、DCL燃煤固硫剂脱硫及烟气循环流化床脱硫技术，对它们的经济、技术性进行了分析比较。     

CFB干法脱硫袋式除尘器设计及运行维护

阐述了CFB干法脱硫工艺,及其配套袋式除尘器的结构型式、设计选型和运行维护等方面的技术问题。     

湿式石灰/石灰石烟气脱硫工艺存在的问题及技术措施

正确处理湿式石灰／石灰石烟气脱硫（FGD）过程的石膏结垢、设备腐蚀等问题,是保证FGD系统长期稳定可靠运行的关键。本文对湿式石灰／石灰石FGD过程中的石膏结垢成因、设备腐蚀原因、烟气再热以及与液固分离等相关的亚硫酸盐的氧化等问题进行了分析,归纳对比了现行技术措施的优缺点。结合我国国情,综合考虑技术可行性和经济合理性等因素,就解决这些问题应采取的适宜措施提出了见解。     

燃煤锅炉湿式脱硫除尘一体化设备的综合分析

本文对湿式脱硫除尘一体化设备的结构和性能进行了较为全面的分析,指出了该设备存在的诸多弊病,提出了解决方案--脱硫、除尘分体组合式的思路.     

浅谈330MW机组半干法脱硫与锅炉同步投退

从我国发电企业的实际出发,结合电力企业的烟气脱硫技术,提出火力发电厂330MW机组半干法脱硫在点炉时同步投入、停炉时同步退出的具体方案、步骤和注意事项。     

Effects of fuel reactivity and injection timing on diesel engine combustion and emissions

Recent strategies for simultaneously reducing NOx and soot emissions have focused on achieving nearly premixed, low-temperature combustion (LTC) in diesel engines. A promising approach in this regard is to vary fuel reactivity in order to control the ignition delay and optimize the level of premixing and reduce emissions. The present study examines such a strategy by performing 3-D simulations in a single-cylinder of a diesel engine. Simulations employ the state-of-the-art two-phase models and a validated semi-detailed reaction mechanism. The fuel reactivity is varied by using a blend of n-heptane and iso-octane, which represent surrogates for gasoline and diesel fuels, respectively. Results indicate that the fuel reactivity strongly influences ignition delay and combustion phasing, whereas the start of injection (SOI) affects combustion phasing. As fuel reactivity is reduced, the ignition delay is increased and the combustion phasing is retarded. The longer ignition delay provides additional time for mixing, and reduces equivalence ratio stratification. Consequently, the premixed combustion is enhanced relative to diffusion combustion, and thus the soot emission is reduced. NO_x emission is also reduced due to reduced diffusion combustion and lower peak temperatures caused by delayed combustion phasing. An operability range is observed in terms of fuel reactivity and SOI, beyond which the mixture may not be sufficiently well mixed, or compression ignited. The study demonstrates the possibility of finding an optimum range of fuel reactivity, SOI, and EGR for significantly reducing engine out emissions for a given load and speed.     

Adsorption of nutrients and cadmium by different minerals: experimental studies and modelling

This work analyses cadmium sorption by natural vermiculite, zeolite, and pumice, which have been recently considered for their potential use in remediation of contaminated soils. Batch experiments were performed to investigate the interactions between the mineral surfaces and the main nutritive cations of Hoagland solution. In addition to their ameliorative effect of reducing metal mobility, these minerals are able to interact to different extents with various components of the nutrient solution and can change the availability of essential nutrients in solution. Therefore, the minerals were also exposed to a range of cadmium doses to compare their different affinities for this element and to analyse the cadmium–nutrient interactions. The results showed that the nutrient solution composition was significantly modified by contact with zeolite and vermiculite, and to a minor extent with pumice. The ionic equilibrium between the solid and aqueous phases was attained at several time points depending on the cation. Ammonium and potassium ions were almost entirely absorbed by zeolite, while in vermiculite endogenous magnesium ions were exchanged with the liquid phase calcium ions. The amount of cadmium adsorbed on mineral surfaces equilibrated with the nutrient solution showed the following sequence zeolite>vermiculite>pumice, and the cation concentrations of the fluid phase were sensitive to cadmium addition.     

Application of coal ash to environmental improvement: Transformation into zeolite, potassium fertilizer, and FGD absorbent

The rapid increase in population and economic growth have led to an increase in energy demand. Coal reserves are distributed worldwide, and coal is now known to be the most stable and available energy source. However, utilization of coal as an energy source involves the generation of a great amount of coal ash, and the recycling rate of the ash is rather low. Coal ash is mainly used in civil construction materials, and there is a limit to the demand for coal ash by construction industries: therefore, the increasing amount of coal ash will be a serious problem in the near future. Different applications should be considered. In this paper, three environmentally-friendly methods for coal ash recycling are described. Firstly, alkali treatment can transform coal ash to zeolite, which is used in deodorant and for wastewater treatment and soil improvement. Secondly, potassium silicate fertilizer is produced from coal ash and has a higher retentivity in the soil than that of conventional fertilizers. Thirdly, emission of sulfur dioxide is controlled by flue gas desulfurization using coal ash. It is considered that environmentally-friendly use of coal ash is important from the viewpoints of energy, economy, and environmental strategy in order to realize the concept of sustainable development.     

Determinants of Trust for Public Lands: Fire and Fuels Management on the Bitterroot National Forest

Management of public lands occurs today with high levels of scrutiny and controversy. To succeed, managers seek the support, involvement, and endorsement of the public. This study examines trust as an indicator of managerial success and attempts to identify and measure the components that most influence it. A review of trust literature yielded 14 attributes that were hypothesized to contribute to trust, grouped into the three dimensions of Shared Norms and Values, Willingness to Endorse, and Perceived Efficacy. Operationalizing these attributes and dimensions, a telephone survey was administered to a sample of Montana, USA, residents living adjacent to the Bitterroot National Forest (n = 1,152). Each of the attributes was measured in the context of federal lands fire and fuel management. Structural equation modeling showed that all 14 attributes were found to be influential contributors to levels of trust. Results suggest that if managers are to maintain or increase levels of public trust, they need to consider each of trust’s attributes as they make social, ecological, and economic resource decisions.     

Clean energy,clean water,and quality education: Prospects of achieving Sustainable Development Goals (SDGs) in Sri Lanka

The Sustainable Development Goal (SDG) 7 targets universal access to affordable, reliable, and modern energy services by 2030. Modern or clean energy is perceived to be the golden thread that connects economic growth, human development, and environmental sustainability. However, one third of the world's population still uses solid fuels for cooking, endangering human health, and the environment. This paper, therefore, analyses demographic, socio-economic, and housing characteristics that affect the fuel choice for cooking. Further, it identifies how SDG 4 (quality education) and SDG 6 (clean water) create synergies with SDG 7 (clean energy). The data are obtained from the four waves of the Sri Lankan Households Income and Expenditure Survey, covering more than 79,000 households. The random-effects panel multinomial logit results reveal that household income, wealth, marital status and education of the head, age and education of the spouse, household size, number of children, housing characteristics, and residential sector are vital in selecting clean fuel for cooking. Furthermore, advanced sustainability analysis shows SDG 4 and 6 have a strong synergistic effect on SDG 7. Policymakers can use the findings to prioritise educational, water, and sanitation programmes in national policies aimed at enhancing the use of clean cooking fuel and technologies to meet SDG 7 by 2030.     

Adsorption of Pb and Cd on the natural surface coatings (NSCs) in the presence of organochlorine pesticides: a preliminary investigation

Adsorption of Pb and Cd in the presence and absence of organochlorine pesticides (OCPs) on natural surface coatings (NSCs), which were collected in the Nanhu Lake in Changchun, China, was measured in order to investigate the effect of the OCPs on the adsorption of heavy metals on the NSCs. Adsorption of Pb/Cd was carried out under controlled laboratory conditions (mineral salt solution with defined species, ionic strength 0.05 mol/l, 25 degrees C and pH 6.0) with initial Pb and Cd concentrations ranging from 0.2 to 2.5 mol/l. The classical Langmuir adsorption isotherm was applied to estimate the equilibrium coefficients of the adsorption of Pb and Cd on the NSCs. Adsorption interference between Pb/Cd and the OCPs on the NSCs indicated that the adsorption of Pb/Cd on the NSCs was influenced by the OCPs, and competitive adsorption between Pb and the OCPs was observed while adsorption of Cd was enhanced by addition of the OCPs. Adsorption data fit the Langmuir isotherm well for the NSCs treated with the OCPs at different equilibrium concentrations. The results showed that the amount of adsorbed Pb decreased by more than 40% while the amount of adsorbed Cd increased by over 60% with an increase in the initial concentrations of the OCPs ranging from 0 to 5.0 microg/l and that adsorption of Pb/Cd on the NSCs was strongly affected by the OCPs. This preliminary study highlights the importance of the OCPs on the NSCs in controlling the transport, fate, biogeochemistry, bioavailability and toxicity of trace metals in aquatic environments.     

Adsorption of phenol and its derivatives from water using synthetic resins and low-cost natural adsorbents: a review

In this article, the technical feasibility of the use of activated carbon, synthetic resins, and various low-cost natural adsorbents for the removal of phenol and its derivatives from contaminated water has been reviewed. Instead of using commercial activated carbon and synthetic resins, researchers have worked on inexpensive materials such as coal fly ash, sludge, biomass, zeolites, and other adsorbents, which have high adsorption capacity and are locally available. The comparison of their removal performance with that of activated carbon and synthetic resins is presented in this study. From our survey of about 100 papers, low-cost adsorbents have demonstrated outstanding removal capabilities for phenol and its derivatives compared to activated carbons. Adsorbents that stand out for high adsorption capacities are coal-reject, residual coal treated with H3PO4, dried activated sludge, red mud, and cetyltrimethylammonium bromide-modified montmorillonite. Of these synthetic resins, HiSiv 1000 and IRA-420 display high adsorption capacity of phenol and XAD-4 has good adsorption capability for 2-nitrophenol. These polymeric adsorbents are suitable for industrial effluents containing phenol and its derivatives as mentioned previously. It should be noted that the adsorption capacities of the adsorbents presented here vary significantly depending on the characteristics of the individual adsorbent, the extent of chemical modifications, and the concentrations of solutes.     

Treatment of Sulfate/Sulfide-Containing Wastewaters Using a Microbial Fuel Cell: Single and Two-Anode Systems

The microbial fuel cell (MFC) was employed to convert reductive potential in sulfate-laden wastewaters to electricity via reducing sulfate to sulfide by sulfate-reducing bacteria and then oxidizing sulfide to sulfur by exoelectrogens. The excess sulfide presented in the anodic solution inhibited the activities of functional strains in MFC. This study proposed the use of a two-anode system, with a sulfate-reducing bacteria anode and an exoelectrogen (C27) anode in the anodic cell, to efficiently convert reductive potential of sulfate into electricity. The microbial community of sulfate-reducing bacteria anode and the electrochemical characteristics of the studied MFCs were reported.     

Fossil fuel divestment: implications for the future of sustainability discourse and action within higher education

This paper provides a critical overview and analysis of the student-led fossil fuel divestment (FFD) movement and its impact on sustainability discourse and actions within US higher education. Analysing higher education institutes’ (HEIs) divestment press releases and news reports shows how institutional alignment with cultures of sustainability and social justice efforts played key roles in HEIs’ decisions to divest from fossil fuels. Key stated reasons for rejection were: minimal or unknown impact of divestment, risk to the endowment, and fiduciary duty. Participant observation and interviews with protagonists reveal the intricate power structures and vested business interests that influence boardroom divestment decision-making. While some HEIs embrace transformative climate actions, we contend that higher education largely embraces a business-as-usual sustainability framework characterised by a reformist green-economy discourse and a reluctance to move beyond business-interest responses to climate politics. Nonetheless, the FFD movement is pushing HEIs to move from compliance-oriented sustainability behaviour towards a more proactive and highly politicised focus on HEIs’ stance in the modern fossil fuel economy. We offer conceptual approaches and practical directions for reorienting sustainability within HEIs to prioritise the intergenerational equity of its students and recognise climate change as a social justice issue. Fully integrating sustainability into the core business of HEIs requires leadership to address fundamental moral questions of both equity and responsibility for endowment investments. We contend that HEIs must re-evaluate their role in averting catastrophic climate change, and extend their influence in catalysing public climate discourse and actions through a broader range of external channels, approaches, and actors.     

Effect of the effective stress coefficient and sorption-induced strain on the evolution of coal permeability: Experimental observations

Permeability is one of the most important parameters for CO₂ injection in coal to enhance coalbed methane recovery. Laboratory characterization of coal permeability provides useful information for in situ permeability behavior of coal seams when adsorbing gases such as CO₂ are injected. In this study, a series of experiments have been conducted for coal samples using both non-adsorbing and adsorbing gases at various confining stresses and pore pressures. Our observations have showed that even under controlled stress conditions, coal permeability decreases with respect to pore pressure during the injection of adsorbing gases. In order to find out the causes of permeability decrease for adsorbing gases, a non-adsorbing gas (helium) is used to determine the effective stress coefficient. In these experiments using helium, the impact of gas sorption can be neglected and any permeability reduction is considered as due to the variation in the effective stress, which is controlled by the effective stress coefficient. The results show that the effective stress coefficient is pore pressure dependent and less than unity for the coal samples studied. The permeability reduction from helium experiments is then used to calibrate the subsequent flow-through experiments using adsorbing gases, CH₄ and CO₂. Through this calibration, the sole effect of sorption-induced strain on permeability change is obtained for these adsorbing gas flow-through experiments. In this paper, experimental results and analyses are reported including how the impact of effective stress coefficient is separated from that of the sorption-induced strain on the evolution of coal permeability.     

Fuel poverty and vulnerability in the EU low-carbon transition: the case of renewable electricity

The European Union (EU) and member states alike are following a tradition of addressing fuel poverty and vulnerability at the point of purchase by final consumers by seeking to influence the impact of income, energy price and the built environment on the ability of household consumers to access the energy that they need. By focusing on the conditions of energy transmission in the most rapidly growing renewable electricity sector in the UK – offshore wind – this paper aims to question whether the regulatory socio-technological framing of renewable electricity transmission is reproducing conditions for fuel poverty and vulnerability in the UK. By drawing a comparison with renewable electricity transmission in Bulgaria, this paper argues that the problem might be symptomatic of the EU as a whole. While not arguing against the proliferation of renewable electricity and its importance in meeting the 2020 targets, this paper calls for expanding the scope of fuel poverty alleviation policy throughout the whole renewable electricity supply chain, building on Helm's argument that energy companies at the middle of the supply chain are better suited to deliver fuel policy.     

Utilization of waste product (tamarind seeds) for the removal of Cr(VI) from aqueous solutions: Equilibrium, kinetics, and regeneration studies

In the present study, an adsorbent was prepared from tamarind seeds and used after activation for the removal of Cr(VI) from aqueous solutions. The tamarind seeds were activated by treating them with concentrated sulfuric acid (98% w/w) at a temperature of 150 °C. The adsorption of Cr(VI) was found to be maximum at low values of initial pH in the range of 1–3. The adsorption process of Cr(VI) was tested with Langmuir, Freundlich, Redlich–Peterson, Koble–Corrigan, Tempkin, Dubinin–Radushkevich and Generalized isotherm models. Application of the Langmuir isotherm to the system yielded a maximum adsorption capacity of 29.7 mg/g at an equilibrium pH value ranging from 1.12 to 1.46. The adsorption process followed second-order kinetics and the corresponding rate constants obtained were 2.605 × 10⁻³, 0.818 × 10⁻³, 0.557 × 10⁻³ and 0.811 × 10⁻³ g/mg min⁻¹ for 50, 200, 300 and 400 mg/L of initial Cr(VI) concentration, respectively. The regenerated activated tamarind seeds showed more than 95% Cr(VI) removal of that obtained using the fresh activated tamarind seeds. A feasible solution is proposed for the disposal of the contaminants (acid and base solutions) containing high concentrations of Cr(VI) obtained during the regeneration (desorption) process.     

SO2 gas adsorption by modified kaolin clays: influence of previous heating and time acid treatments

Modified kaolin clays were used as adsorbents for SO(2) gas adsorptions. The clays were heated up to 900 °C previous to acid treatments with 0.5 N sulfuric acid solutions at boiling temperature during different times up to 1440 min. Equilibrium adsorption at 25 °C and 0.1 MPa was carried out by using a volumetric apparatus. The samples were characterized by chemical analysis, X-ray diffraction and infrared analysis. The heating of the clays followed by acid treatment improved the adsorption capacity of the kaolin clays. The presence of amorphous silica and hydroxyl in the final products improved SO(2) adsorption capacity. Better properties for SO(2) adsorption were found in kaolin rich in not well ordered kaolinite clay mineral.     

Identifying Biotic Integrity and Water Chemistry Relations in Nonwadeable Rivers of Wisconsin: Toward the Development of Nutrient Criteria

We sampled 41 sites on 34 nonwadeable rivers that represent the types of rivers in Wisconsin, and the kinds and intensities of nutrient and other anthropogenic stressors upon each river type. Sites covered much of United States Environmental Protection Agency national nutrient ecoregions VII—Mostly Glaciated Dairy Region, and VIII—Nutrient Poor, Largely Glaciated upper Midwest. Fish, macroinvertebrates, and three categories of environmental variables including nutrients, other water chemistry, and watershed features were collected using standard protocols. We summarized fish assemblages by index of biotic integrity (IBI) and its 10 component measures, and macroinvertebrates by 2 organic pollution tolerance and 12 proportional richness measures. All biotic and environmental variables represented a wide range of conditions, with biotic measures ranging from poor to excellent status, despite nutrient concentrations being consistently higher than reference concentrations reported for the regions. Regression tree analyses of nutrients on a suite of biotic measures identified breakpoints in total phosphorus (~0.06 mg/l) and total nitrogen (~0.64 mg/l) concentrations at which biotic assemblages were consistently impaired. Redundancy analyses (RDA) were used to identify the most important variables within each of the three environmental variable categories, which were then used to determine the relative influence of each variable category on the biota. Nutrient measures, suspended chlorophyll a, water clarity, and watershed land cover type (forest or row-crop agriculture) were the most important variables and they explained significant amounts of variation within the macroinvertebrate (R ² = 60.6%) and fish (R ² = 43.6%) assemblages. The environmental variables selected in the macroinvertebrate model were correlated to such an extent that partial RDA analyses could not attribute variation explained to individual environmental categories, assigning 89% of the explained variation to interactions among the categories. In contrast, partial RDA attributed much of the explained variation to the nutrient (25%) and other water chemistry (38%) categories for the fish model. Our analyses suggest that it would be beneficial to develop criteria based upon a suite of biotic and nutrient variables simultaneously to deem waters as not meeting their designated uses.