超临界二氧化碳萃取再生吸苯活性炭的研究

以工业废水中的典型污染物苯作为单一吸附质,进行了超临界二氧化碳萃取再生活性炭研究,探讨了操作温度、操作压力、CO2流速、活性炭粒度、循环再生次数等因素对再生效率及再生速率的影响。试验结果表明,超临界CO2对活性炭中的苯具有良好的再生效果。     

山东电力产业低碳化技术路线研究

目前山东省年CO2排放量超过10亿t,电力行业的排放量占40％,因此,电力产业低碳化对山东省发展低碳经济具有举足轻重的作用.山东具有丰富的风能、生物质能等清洁能源,据规划,到2020年,清洁能源发电实现年减排CO210％;国内首座整体煤气化联合循环项目于山东投产,与相同装机容量燃煤电厂相比,其CO2排放量降低13.73％,若与碳捕捉和封存(CCS)技术联用,可实现CO2近零排放;山东省超临界/超超临界机组装机容量达932万kW,关停小机组600万kW,年减排CO22100万t.山东电力产业应因地制宜发展清洁能源发电,大力发展IGCC、超临界/超超临界等高效发电技术.同时,鼓励电力产业积极借助清洁发展机制(CDM),完善低碳路线.     

火电厂CO_2减排技术及成本探讨

介绍了我国火电厂CO2排放特点,阐述了火电厂CO2减排技术、成本及影响因素,分析了CO2减排对中国未来能源和经济的影响。指出最适合CO2捕集技术发展的电厂类型是超超临界燃煤电厂和IGCC电厂,CO2减排技术的研发重点是大幅度降低成本和效率损失。     

L-精氨酸溶剂化合成金属有机骨架化合物及其吸附CO2的性能

采用L-精氨酸对传统均苯三甲酸（BTC）溶剂热法合成的Cu基金属有机骨架化合物（Cu-BTC）进行改性,得到新型化合物（Cu-BTC-Arg）,并通过固定床动态吸附实验考察了Cu-BTC-Arg和Cu-BTC吸附CO2的性能。表征结果显示：L-精氨酸只是辅助化溶剂,并未配位至Cu2+上;Cu-BTC-Arg比Cu-BTC具有更小的晶粒尺寸、更大的比表面积和微孔体积。实验结果表明,两种不同L-精氨酸加入量合成的Cu-BTC-Arg均在室温、烟气中无水蒸气、烟气流量80 mL/min的条件下CO2吸附量最大,吸附接近饱和时的CO2吸附量均为4.9 mmol/g,远高于Cu-BTC的CO2吸附量。Cu-BTC-Arg对CO2的吸附以物理吸附为主。     

CO2资源化利用的现状及前景

介绍了CO2分离捕集最新工艺——电化学法、膜法、化学循环燃烧法的研究进展。评述分析了CO2的各种资源化应用前景：CO2气体用作生物碳源、辅助注射成型剂及有机物（如氨基甲酸酯、表面活性剂）合成原料等;液态CO2用于人造金刚石、热泵干燥、超临界CO2萃取及固体干冰冷喷射清洗等。CO2作为一种潜在的丰富碳源,应不断研发其新的应用领域,加快其工业化应用。     

超临界氨水改性活性炭及其对CO2的吸附性能

采用超临界氨水改性活性炭(AC),考察了改性AC对CO2的吸附性能,表征了改性前后AC的表面结构和化学性质.实验结果表明,改性温度为150℃制备的改性AC具有最高的CO2吸附量,25℃时吸附量从改性前的0.979 mmol/g增至1.291 mmol/g,增加了约30％.表征结果显示:改性后AC表面成功负载了含氮基团;...     

信息与动态

CO2捕集工艺进入工业化试验;超临界水裂解渣油;纳米孔穴改善TiO2的光吸收性;美国DowCorning公司承担“废物变能源”项目。     

国外动态

超临界水热分解煤制 H2 和 CH4资源环境对策 ,2 0 0 0 ,3 6(10 ) :5 1　　日本工技院资源综合利用研究所和煤炭利用综合中心共同开发成功用超临界水热分解煤等有机物制造 80 % H2 和 2 0 % CH4 气体的新技术。每克煤可生成 2～ 3L气体 ,煤中碳或氢几乎可全部按理论量进行反应 ,生成的气体中不含硫化物。同时氢气生成时能和副反应生成的 CO2 分离 ,使 H2 能高质量浓缩 ,用作燃料。新工艺产生的氯化物、氮化物、硫化物等都能以无害化形式被分离。　　该技术除煤以外 ,还可用于分解其他有机物 (碳源 ) ,如生活垃圾、家畜粪尿、动植物残体、…     

钙基固定剂对制氢和污染性气体减排的影响

在未来相当长的一段时间内,煤气化仍是大规模制取氢气的主要途径。目前,常规煤气化过程得到的是H2、CO和CO2为主的混合气,需要通过净化、变换和分离工艺才能得到洁净的氢气,工艺过程复杂。采用连续式超临界水反应装置,以质量分数为20%的水煤浆为反应原料,考察了Ca/C摩尔比和温度对褐煤制氢系统的影响。试验结果表明：Ca（OH）2不仅可以很好地固定气相中的CO2和硫化物,而且对煤气化过程也表现出较好的催化作用。反应温度600℃,压力为25MPa的条件下,与未加Ca（OH）2相比,Ca/C摩尔比为0.45时,气体中CO2的体积分数由50.7%降至1.0%,趋于完全固定;硫化物浓度由10 878mg/m3降至807mg/m3;H2的体积分数由32.4%增至73.3%。Ca（OH）2对煤气化的催化作用在高温下更加明显。     

金属有机骨架材料Cu2(BTC)3对CO2的吸附

采用溶剂热法,以均苯三甲酸(H3BTC)为有机配体与硝酸铜进行反应合成了Cu2(BTC).通过XRD和SEM等方法对Cu2(BTC)3进行了表征.实验结果表明,Cu2(BTC)3是一种典型的金属有机骨架(MOFs)材料,呈现规整的八面体晶状结构,晶粒大小为2～20 μm.相同条件下Cu2(BTC)3对CO2的吸附量高于活性炭和活性碳纤维,且随着吸附压力的升高吸附量明显增大,随着吸附温度的降低吸附量也增大.在0.4 MPa、25℃的条件下,用Cu2(BTC)3作吸附剂可以很好地分离CO2体积分数为5％和20％的CO2-甲烷混合气体,且对CO2含量低的混合气体分离效果更好.     

Accelerated carbonation treatment of industrial wastes

The disposal of industrial waste presents major logistical, financial and environmental issues. Technologies that can reduce the hazardous properties of wastes are urgently required. In the present work, a number of industrial wastes arising from the cement, metallurgical, paper, waste disposal and energy industries were treated with accelerated carbonation. In this process carbonation was effected by exposing the waste to pure carbon dioxide gas. The paper and cement wastes chemically combined with up to 25% by weight of gas. The reactivity of the wastes to carbon dioxide was controlled by their constituent minerals, and not by their elemental composition, as previously postulated. Similarly, microstructural alteration upon carbonation was primarily influenced by mineralogy. Many of the thermal wastes tested were classified as hazardous, based upon regulated metal content and pH. Treatment by accelerated carbonation reduced the leaching of certain metals, aiding the disposal of many as stable non-reactive wastes. Significant volumes of carbon dioxide were sequestrated into the accelerated carbonated treated wastes.     

Control of GHG emission at the microbial community level

All organic material eventually is decomposed by microorganisms, and considerable amounts of C and N end up as gaseous metabolites. The emissions of greenhouse relevant gases like carbon dioxide, methane and nitrous oxides largely depend on physico-chemical conditions like substrate quality or the redox potential of the habitat. Manipulating these conditions has a great potential for reducing greenhouse gas emissions. Such options are known from farm and waste management, as well as from wastewater treatment. In this paper examples are given how greenhouse gas production might be reduced by regulating microbial processes. Biogas production from manure, organic wastes, and landfills are given as examples how methanisation may be used to save fossil fuel. Methane oxidation, on the other hand, might alleviate the problem of methane already produced, or the conversion of aerobic wastewater treatment to anaerobic nitrogen elimination through the anaerobic ammonium oxidation process might reduce N2O release to the atmosphere. Changing the diet of ruminants, altering soil water potentials or a change of waste collection systems are other measures that affect microbial activities and that might contribute to a reduction of carbon dioxide equivalents being emitted to the atmosphere.     

Environmental assessment and accounting for the waste disposal stream in Bangkok,Thailand

It is very important that waste should be controlled and appropriately handled in a waste disposal stream, considering its impact on the environment. In this research, the LCA-EA model was applied to the current waste disposal stream of the BMR as well as other waste disposal stream scenarios, so that treatment cost, environmental load and environmental cost were assessed quantatively. The results of this study showed that in the current waste diposal stream in Bangkok, there were large contributions from carbon dioxide and methane to the greenhouse gas emissions from the stream. The study was able to quantify the reductions in environmental load associated with various waste disposal stream scenarios, using the baseline scenario as a standard.     

Study of the Determination of the Ultimate Aerobic Biodegradability of Plastic Materials Under Controlled Composting Conditions

Several ISO standards for determining the ultimate aerobic/anaerobic biodegradability of plastic materials have been published. In particular, ISO 14855-1 is a common test method that measures evolved carbon dioxide using such methods as continuous infrared analysis, gas chromatography or titration and others (ISO 14855-1(2005.9)). This method is a small-scale test for determining the ultimate aerobic biodegradability of plastic materials, where the amounts of compost inoculum and test sample in one tenth comparing with that of ISO 14855-1. This method is well versed in ISO/DIS 14855-2 which the carbon dioxide evolved from test vessel is determined by gravimetric analysis of carbon dioxide absorbent. The focus of this study is to elucidate statistically the results of round robin test by seven countries used MODA, which were various deviations among the experiments.     

高温分解及烟气净化处理电子垃圾的技术和设备

提出高温分解及烟气净化处理废弃电子垃圾的技术。通过喷水系统调节分解炉内气氛,控制有机物分解速度,使有机物裂解成二氧化碳和水蒸气,有害成份经净化系统再次处理后达到环保排放标准。金属部分可进一步进行提炼回收,实现有机物和金属的绿色分离。     

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.     

Wood Residues as Raw Material for Biorefinery Systems: LCA Case Study on Bioethanol and Electricity Production

Fossil energy and chemical sources are depleting. There is a critical need to change the current industry and human civilization to a sustainable manner, assuring that our way of life actual continues on the path of improvement after the depletion of fossil energy sources. The utilization of agricultural residues as raw materials in a biorefinery is a promising alternative to fossil resources for production of energy carriers and chemicals, thus mitigating climate change and enhancing energy security. Biorefinery is a concept of converting lignocellulosic biomass or grains (such as corn) to chemicals, materials and energy on which human civilization runs, replacing the need for petroleum, coal, natural gas, and other nonrenewable energy and chemical sources. Lignocellulosic biomass is renewable, that is plant synthesizes chemicals (by drawing energy from the sun and carbon dioxide) and water from the environment, while releasing oxygen. Combustion of biomass releases energy, carbon dioxide and water. Therefore, biorefinery plays a key role in satisfying human needs for energy and chemicals by using the biomass production and consumption cycle. This paper focuses on a biorefinery concept and in particular on the bioethanol production from wood residues. In order to evaluate the environmental reliability of the system under study, the biorefinery plant (producing bioethanol and electricity from wood residues) was compared, by using the LCA methodology, to both conventional refinery system (producing light fuel oil and electricity from petroleum) and biorefinery plant based on corn feedstock producing the same goods. Interesting considerations about LUC emissions effect on biorefinery sustainability are also reported. The obtained results show that by assigning reasonable values to the three damage categories used in the eco-indicator 99 methodology the biorefinery system is preferable, from an environmental point of view, to the conventional refinery system analysed. This finding confirms the high potentials of this innovative plant technology.     

Co-gasification of municipal solid waste and material recovery in a large-scale gasification and melting system

This study evaluates the effects of co-gasification of municipal solid waste with and without the municipal solid waste bottom ash using two large-scale commercial operation plants. From the viewpoint of operation data, there is no significant difference between municipal solid waste treatment with and without the bottom ash. The carbon conversion ratios are as high as 91.7% and 95.3%, respectively and this leads to significantly low PCDD/DFs yields via complete syngas combustion. The gross power generation efficiencies are 18.9% with the bottom ash and 23.0% without municipal solid waste bottom ash, respectively. The effects of the equivalence ratio are also evaluated. With the equivalence ratio increasing, carbon monoxide concentration is decreased, and carbon dioxide and the syngas temperature (top gas temperature) are increased. The carbon conversion ratio is also increased. These tendencies are seen in both modes.Co-gasification using the gasification and melting system (Direct Melting System) has a possibility to recover materials effectively. More than 90% of chlorine is distributed in fly ash. Low-boiling-point heavy metals, such as lead and zinc, are distributed in fly ash at rates of 95.2% and 92.0%, respectively. Most of high-boiling-point heavy metals, such as iron and copper, are distributed in metal. It is also clarified that slag is stable and contains few harmful heavy metals such as lead. Compared with the conventional waste management framework, 85% of the final landfill amount reduction is achieved by co-gasification of municipal solid waste with bottom ash and incombustible residues. These results indicate that the combined production of slag with co-gasification of municipal solid waste with the bottom ash constitutes an ideal approach to environmental conservation and resource recycling.     

Steam gasification of waste tyre: Influence of process temperature on yield and product composition

An experimental survey of waste tyre gasification with steam as oxidizing agent has been conducted in a continuous bench scale reactor, with the aim of studying the influence of the process temperature on the yield and the composition of the products; the tests have been performed at three different temperatures, in the range of 850–1000 °C, holding all the other operational parameters (pressure, carrier gas flow, solid residence time). The experimental results show that the process seems promising in view of obtaining a good quality syngas, indicating that a higher temperature results in a higher syngas production (86 wt%) and a lower char yield, due to an enhancement of the solid–gas phase reactions with the temperature. Higher temperatures clearly result in higher hydrogen concentrations: the hydrogen content rapidly increases, attaining values higher than 65% v/v, while methane and ethylene gradually decrease over the range of the temperatures; carbon monoxide and dioxide instead, after an initial increase, show a nearly constant concentration at 1000 °C. Furthermore, in regards to the elemental composition of the synthesis gas, as the temperature increases, the carbon content continuously decreases, while the oxygen content increases; the hydrogen, being the main component of the gas fraction and having a small atomic weight, is responsible for the progressive reduction of the gas density at higher temperature.     

Technical feasibility and conceptual design for using supercritical fluid to extract pesticides from aged soil

The demand for processes to clean up contaminated soils without introducing additional contaminants is increasing. One approach to solving this problem is the use of supercritical fluids like carbon dioxide, alone or with cosolvents, to extract contaminants from the soil. Carbon dioxide is readily available, inexpensive, and nonpolluting. Gases exhibit unique properties under supercritical conditions. They retain the ability to diffuse through the interstitial spaces of solid materials, plus they have the solvating power of liquids. Soil cleanup using supercritical fluid extraction (SFE) is being investigated as an alternative/complementary technology to other cleanup methods such as incineration and bioremediation. The objective of the studies included in this article was to collect and analyze data to support use of the SFE technology and to provide the conceptual design and operational processes needed for building a portable treatment unit.