Agricultural C cycle and greenhouse gas emission in China

This paper assesses the production, consumption and store of organic carbon in the agricultural system, including all products from agriculture, of China. An estimation showed that about 90% of carbon uptake by agricultural systems would be emitted or returned to the atmosphere by several types from 1990 to 2000, others remain in durable agricultural products and soil. Even though the fixation rate is getting lower, generally speaking Chinese agriculture is a “sink” but not a “source” in respect to the atmospheric CO₂ and CH₄ concentrations in both the current period and that after few decades. China's Soil stores 12% of the whole soil carbon in the World. Considering the different global warming potentials (GWP), an approach to the country budgets of CO₂ and CH₄ has been presented based on the measurements in rice paddies and in the Tibet and Inner Mongolia grasslands. This revised version was published online in August 2006 with corrections to the Cover Date.     

基于全寿命周期成本的压缩空气储能系统储气装置经济性分析

综合考虑压缩空气储能系统经济性对于储能系统的设计和大规模应用具有重要意义。本文基于全寿命周期成本模型分析的方法,建立了不同类型的储气装置成本模型。通过计算储气装置的理论金属消耗量、储气装置的数量,同时在考虑制造难易程度的基础上来确定不同类型储气装置的最佳参数。通过对不同类型的储气装置进行全寿命周期成本分析和比较,可作为设计压缩空气储能系统及其经济性分析的参考。储气装置的全寿命周期成本（LCC）包括早期和后期成本。早期成本主要由原材料和设备成本构成,后期成本主要是运行维护成本。根据分析结果,储气管道的投资成本最低,且没有压力限制。地面储气装置的设备成本一般在2USD/kW·h左右。在确保安全的前提下,降低地面储气装置的LCC有利于压缩空气储能系统的推广实施和工程应用,大规模、有效地提高可再生能源的利用率,降低可再生能源的间歇性对电网运行的影响。     

Optimization-based identification of CO2 capture and utilization processing paths for life cycle greenhouse gas reduction and economic benefits

This paper introduces a mathematical formulation to identify promising CO₂ capture and utilization (CCU) processing paths and assess their production rates by solving an optimization problem. The problem is cast as a multi-objective one by simultaneously maximizing a net profit and life cycle greenhouse gas (GHG) reduction. Three case studies are illustrated using an exemplary CCU processing network. The results indicate the optimal solution is greatly influenced by the scale of CO₂ emission source, market demand, and hydrogen availability. Moreover, with the current system of measuring the GHG reduction regarding a business-as-usual level, if the aim is to achieve a GHG reduction within a national boundary, the question of whether CCU plants producing a product of same functionality through conventional means, which the CO₂-based product can replace, exists in the country can come into consideration. This systematic identification will assist decision-making regarding future R&D investment and construction of large-scale CCU plants.     

低成本合成气与合成气转化新技术

现有工艺和技术对合成气原料要求较高,造成了下游产品的成本偏高。研究了低成本合成气尤其是含氮合成气的利用技术,并对合成气制二甲醚、F-T合成、低温液相甲醇合成等新技术进行了介绍,指出了利用含氮合成气等低成本合成气存在的问题,并展望了其应用前景。     

Life cycle emissions of greenhouse gas for ammonia scrubbing technology

It is thought that the CO₂ emissions from coal-fired power plants contribute greatly to the total anthropogenic CO₂ emissions. Ammonia solvent can be used to absorb the CO₂, called ammonia scrubbing. However, as has been pointed out, the production of ammonia would emit CO₂; therefore, the effectiveness of ammonia scrubbing is doubted. The paper focuses on the problem. Two systems are defined in the paper. System I is CO₂ absorption by ammonia scrubbing, and system II is industrial production of ammonium bicarbonate. The total CO₂ emissions of the two systems are calculated by means of life cycle assessment. The paper shows that the total CO₂ emissions of ammonia scrubbing are less than that of the industrial production of fertilizer ammonium bicarbonate. It can be concluded that ammonia scrubbing is an effective way to reduce the anthropogenic CO₂ emissions. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

煤基液体燃料生产过程温室气体CO2排放与能效问题研究

基于煤炭化工行业的需要,利用已开发的模型对山西省某地煤种,在不同的气化工艺下（GE—Texaco／Shell）,进行100万t煤基甲醇项目、10万t煤基合成燃料油（间接法）工厂全系统的能源效率、CO2排放量的计算,并对结果进行了初步分析。     

Game theory approach to optimal design of shale gas supply chains with consideration of economics and life cycle greenhouse gas emissions

This article addresses the optimal design of a non‐cooperative shale gas supply chain based on a game theory approach. Instead of assuming a single stakeholder as in centralized models, we consider different stakeholders, including the upstream shale gas producer and the midstream shale gas processor. Following the Stackelberg game, the shale gas producer is identified as the leader, whose objectives include maximizing its net present value (NPV) and minimizing the life cycle greenhouse gas (GHG) emissions. The shale gas processor is identified as the follower that takes actions after the leader to maximize its own NPV. The resulting problem is a multiobjective mixed‐integer bilevel linear programming problem, which cannot be solved directly using any off‐the‐shelf optimization solvers. Therefore, an efficient projection‐based reformulation and decomposition algorithm is further presented. Based on a case study of the Marcellus shale play, the non‐cooperative model not only captures the interactions between stakeholders but also provides more realistic solutions. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2671–2693, 2017     

Analyzing the energy intensity and greenhouse gas emission of Canadian oil sands crude upgrading through process modeling and simulation

This paper presents an evaluation of the energy intensity and related greenhouse gas/CO₂ emissions of integrated oil sands crude upgrading processes. Two major oil sands crude upgrading schemes currently used in Canadian oil sands operations were investigated: cokingbased and hydroconversion-based. The analysis, which was based on a robust process model of the entire process, was constructed in Aspen HYSYS and calibrated with representative data. Simulations were conducted for the two upgrading schemes in order to generate a detailed inventory of the required energy and utility inputs: process fuel, steam, hydrogen and power. It was concluded that while hydroconversion-based scheme yields considerably higher amount of synthetic crude oil (SCO) than the cokerbased scheme (94 wt-% vs. 76 wt-%), it consumes more energy and is therefore more CO₂-intensive (413.2 kg CO₂/m³ SCO vs. 216.4 kg CO₂/m³ SCO). This substantial difference results from the large amount of hydrogen consumed in the ebullated-bed hydroconverter in the hydroconversion-based scheme, as hydrogen production through conventional methane steam reforming is highly energy-intensive and therefore the major source of CO₂ emission. Further simulations indicated that optimization of hydroconverter operating variables had only a minor effect on the overall CO₂ emission due to the complex trade-off effect between energy inputs.     

天然气水合物的有效能量及CO_2排放强度分析

与天然气、石油、煤等常规化石能源以富集态赋存、以赋存态开采不同,天然气水合物大都以固态分散赋存于地层的孔隙中,对其中所含天然气的开采要求水合物的原位分解。天然气水合物原位分解需要能量输入,既包括水合物的分解焓,也包括水合物和多孔地层(介质)升温所需的热量。由于天然气水合物的赋存条件差异很大,开采时水合物和多孔地层升温所需的热量不同,一些条件下天然气水合物的可利用能量(有效能量)会远低于常规天然气,单位有效能量所产生的总CO2排放量甚至会高于石油和煤。为了量化认识这个现象,本文进行了天然气水合物开采能耗的热力学计算,分析了水合物赋存状况与产出天然气的有效(净)能量的关系,计算和讨论了不同赋存条件下天然气水合物在热能利用过程中的二氧化碳排放强度,并与常规化石能源进行了对比。     

多年冻土区沥青路面寿命周期费用分析

应用多种方法对多年冻土地区5种不同路面结构进行了寿命周期费用分析.结果表明,在贴现率为5%时,尽管沥青稳定基层结构的初建费用比其他结构大,但其寿命周期费用现值却比其他基层结构方案小,同时,在路面使用性能上,沥青稳定基层结构对冻土路基不均匀沉降具有较强的适应性,在防止路面结构水损坏方面具有明显优势.因此,综合考虑寿命周期费用、路用性能等方面,提出在多年冻土地区使用沥青稳定基层更为合理可行.     

煤基甲醇生命周期温室气体排放评价

将Input-Output分析方法引入LCA评价中,建立了HybridLCA评价方法。利用该方法对煤基M100（100％甲醇）车用替代燃料生命周期温室气体排放进行评价。结果表明：相同热值煤基M100燃料温室气体排放比传统汽油高许多,因此建议在生产阶段采用CO2捕集和储存技术和重点提高煤炭燃烧利用效率。     

污水处理厂运行工况对温室气体排放的影响

市政污水处理厂是城市的重要基础设施之一,其因在运行过程中产生大量的CO₂、CH₄和N₂O等气体而被视为温室气体（GHGs）的重要来源之一,同时又因其减排潜力较大,引起了各界学者的广泛关注。GHGs减排需求正推动着污水处理厂朝着优化核心运行参数及资源能源回收的低碳方向发展。本文简述了污水处理厂中GHGs直接排放的主要环节和产生机理以及目前常用核算方法中存在的主要问题,并总结了污水处理厂运行工况的变化,包括温度、pH、进水C/N、污泥停留时间（SRT）、亚硝酸盐浓度、溶解氧（DO）浓度对其直接排放的GHGs的影响。分析表明进水C/N、DO浓度、pH和亚硝酸盐浓度对GHGs的排放影响较为明显且它们的变化更易于进行人为干预,人为减排潜力较大。最后总结了目前已有相关研究存在的主要问题以及对未来研究方向的展望,以期为污水处理厂优化运行工况和GHGs减排提供参考。     

Spatial patterns of greenhouse gas emission in a tropical rainforest in Indonesia

Spatial patterns of CO₂, CH₄, and N₂O flux were analyzed in the soil of a primary forest in Sumatra, Indonesia. The fluxes were measured at 3-m intervals on a sampling grid of 8 rows by 10 columns, with fluxes found to be below the minimum detection level at 12 points for CH₄ and 29 points for N₂O. All three gas fluxes distributed log-normally. The means and standard deviations of CO₂ and CH₄ fluxes calculated by the maximum likelihood method were 3.68 ± 1.32 g C m^–2 d^–1 and 0.79 ± 0.60 mg C m^–2 d^–1, respectively. The mean and standard deviation of N₂O fluxes using a maximum likelihood estimator for the censored data set was 2.99 ± 3.26 g N m^–2 h^–1. The spatial dependency of CH₄ fluxes was not detected in 3-m intervals, while weak spatial dependency was observed in CO₂ and N₂O fluxes. The coefficients of variation of CH₄ and N₂O were higher than that of CO₂. Some hot spots where high levels of CH₄ and N₂O were generated in the studied field may increase the variability of these gases. The resulting patterns of variability suggest that sampling distances of >10 m and > 20 m are required to obtain statistically independent samples for CO₂ and N₂O flux in the studied field, respectively. But because of weak or no spatial dependency of each flux, a sampling distance of more than 10 m intervals is enough to prevent a significant problem of autocorrelation for each flux measurement.     

工业固废活化钾长石-CO2矿化提钾的生命周期碳排放与成本评价

利用工业固废活化非水溶性钾长石矿,矿化固定二氧化碳（CO₂）并提钾工艺,是同时处理工业固废、开发钾资源、减排CO₂等一举多得的CCUS路线。采用生命周期评价（LCA）方法,以生产含1 t K₂O的钾肥为功能单元,以传统的高炉冶炼钾长石制可溶性钾肥并联产白水泥工艺作为参照,对比评价了两种钾长石-工业固废体系矿化CO₂联产钾肥工艺过程的碳减排潜力和经济性。对工艺从原料开采、运输到产品生产的生命周期的温室气体排放量（简称“碳排放”）和成本进行了全流程的核算,研究了更全面的产品碳排放和成本分配方法。结果表明,无论是碳排放还是经济性,钾长石-工业固废体系矿化CO₂联产钾肥工艺均较传统工艺有很大提高,碳减排潜力分别可达81.16%和20.48%左右,成本可节约34.75%和45.11%左右。     

Software programme that calculates the life cycle cost of air filters

Air filters are an essential part of any ventilation system and make a significant contribution to indoor air quality. It is important that they are selected not only on the basis of their efficiency, but also on their life cycle cost (LCC), i.e. the total cost over its lifetime. Jan Gustavsson, Camfil Farr, Sweden, explains the theory behind LCC analysis and shows how a computer software programme can help users and designers of air handling systems select filters with optimum LCC.     

Biochar-mediated regulation of greenhouse gas emission and toxicity reduction in bioremediation of organophosphorus pesticide-contaminated soils

Organophosphorus pesticides (OPPs) are a set of toxic persistent organic pollutants (POPs) present in the environment. Recently, biochar-mediated bioremediation has exhibited many advantages over conventional methods for the remediation of pesticide-contaminated soil. In the present study, biochar and nitrogen fertilizer (NH₄NO₃) were employed to remediate OPP-contaminated soil and the greenhouse gas (GHG) emission during 90 days of incubation was investigated. After thermal desorption treatment, the content of organophosphorus pesticides reduced from 175.61 μg·kg^-1 to 62.68 μg·kg^-1. The addition of NH₄NO₃ in the following bioremediation led to larger reduction (34.35%) of the pesticide concentration than that of biochar (31.90%) for the contaminated soils with thermal desorption treatment, while the simultaneous addition of biochar and NH₄NO₃ led to the largest reduction of pesticide concentration (11.07%) for the soil without thermal desorption treatment. The addition of biochar and NH₄NO₃ only slightly increased the emission rate of GHGs from the soil without thermal treatment, but remarkably increased the emission rate of GHGs from the soil after thermal treatment. In most cases, the addition of NH₄NO₃ is more effective than biochar to promote the degradation of pesticide, but also exhibited higher GHG emission. The microbial community analysis suggests that the enhanced degradation of pesticide is mainly owing to the increased activity of microorganism.     

Review of energy consumption research for papermaking industry based on life cycle analysis

Papermaking industry is a high-energy-consuming industry with long supply chain. The growth of paper product demand further intensifies the need of energy consumption. Energy saving through the full supply chain has become a focal point for long-term sustainable development of the papermaking industry.This paper reviews the advances in life cycle analysis for the papermaking industry in recent years. All the stages from the full supply chain are involved to give a panoramic overview of the papermaking industry.The object of this paper is to provide scientific basis to industry and decision-makers with profound understanding of the energy consumption and energy saving potential in a life cycle perspective.     

Radiation-grafted materials for energy conversion and energy storage applications

Polymer electrolyte membranes are key components in electrochemical power sources that are receiving ever-growing demand for the development of more efficient, reliable and environmentally friendly energy systems. Ongoing research is focusing on materials with high ionic conductivity and stability, at low cost. Among different methods, radiation-induced grafting is a universal attractive method for preparation of polymer electrolyte materials with tunable properties for various energy conversion and energy storage applications. This review addresses recent advances in the application of radiation-induced grafting techniques for the preparation of polymer electrolyte membranes/separators for emerging electrochemical devices such as fuel cells, batteries and supercapacitors. The challenges associated with the current state-of-the-art materials are highlighted, together with new directions that should be considered for future research.     

动力系统利用液化天然气冷能的节能减排分析

针对动力系统CO₂减排能耗过高的问题,将液化天然气（LNG）的冷能集成用于空气分离制氧和CO₂近零排放动力循环的CO₂捕集,提出了一种利用LNG冷能的CO₂近零排放动力系统设计方案。研究结果表明：空分装置利用LNG冷能生产高压氧气、液氮和液氩等产品,生产能耗比传统空分装置降低57.6％,CO₂近零排放动力循环的火用效率可从52%提高至55.9％。同时,建立了CO₂近零排放动力系统利用LNG冷能的节能减排效益的数学模型,并对动力系统参数进行了分析。以一个进口量为3.0×10⁶ t·a^-1的接收站为例,CO₂近零排放动力系统利用接收站的LNG冷能每年可节省用电2.78×10⁸ kW·h,减少排放CO₂约3.87×10⁵ t·a^-1,经济效益可达到2.19亿元·a^-1。     

Preparation of low cost activated carbons from various biomasses with microwave energy

Activated carbons are generated from various waste biomass sources such as waste tea, almond shells, tomato stems and leaves. Porous materials were prepared with phosphoric acids activation by microwave energy in a covered Teflon reactor for 1, 2, 3, and 4?min. The activated carbons were characterised in terms of surface area, pore size distribution, pore volume, FTIR analysis. The highest surface areas were obtained using almond shells (1,002?m²/g), waste tea (702?m²/g), tomato stems (813?m²/g) and tomato leaves (117?m²/g), respectively. The type of the raw material has significant effects on the characteristics of the final product. It was shown that porous carbons with high surface area could be prepared by short microwave radiation periods such as 2?C3?min.