聚羟基烷酸酯降解包装材料的生物合成及进展

目的综述聚羟基烷酸酯(Polyhydroxyalkanoates,PHAs)的生物合成工艺、影响因素及其在包装工业领域的应用研究进展,以期优化其生产工艺、降低生产成本、提高PHAs的产量。方法通过对近年来国内外研究现状和研究成果的分析和总结,介绍PHAs的生物合成工艺、影响PHAs产量的主要因素及在包装方面的应用。结论好氧瞬时供料法合成的PHAs产量高于微好氧-好氧工艺;底物种类、C/N值、pH值、溶解氧浓度和合成温度对生物合成PHAs的产量和成分比例都有很大影响;PHAs作为可降解材料在包装领域具有广阔的应用前景,未来的重点研究方向是优化PHAs的合成工艺和影响因素,降低其生产成本,提高产量和产品性能。     

生物降解包装材料聚羟基脂肪酸酯的工艺研究进展

目的 高昂的生产成本制约着绿色包装材料聚羟基脂肪酸酯（Polyhydroxyalkanoates, PHAs）的发展,通过对其生物合成过程中的碳源底物、影响因素的研究,实现其低成本、高效率合成以及规模化应用。方法 归纳分析现阶段国内外PHAs的研究现状和成果,介绍合成PHAs的碳源底物、微生物培养方式以及在合成阶段溶解氧（DO）、pH值、碳氮比等因素对PHAs合成效率的影响。结论 廉价的生物质资源、合理的碳氮比、多批次好氧/厌氧培养、较低的溶解氧浓度、中性或碱性培养环境已经成为提高PHAs产量、降低PHAs生产成本的重要手段。随着生产工艺的不断优化,绿色生物塑料PHAs的规模化生产及其广泛应用必将推动包装材料向绿色化、安全化方向发展。     

Process analysis and optimization of biodiesel production from soybean oil

The overall goal of this work is to design and optimize a biodiesel production process from soybean oil. To achieve this goal, several inter-connected activities were undertaken. First, an initial flowsheet for the process was synthesized. The performance of this flowsheet along with the key design and operating criteria were identified by conducting computer-aided simulation using ASPEN Plus. Various scenarios were simulated to provide sufficient understanding and insights and to select a base-case flowsheet. Next, mass and energy integration studies were performed to reduce the consumption of material and energy utilities, improve environmental impact, and enhance profitability. Capital cost estimation was carried out using the ICARUS Process Evaluator computer-aided tool linked to the results of the ASPEN Plus simulation. The operating cost of the process was estimated using the key information on process operation such as raw materials, utilities, and labor. A profitability analysis was carried out by examining the return on investment and the payback period. It was found that the cost of soybean oil is the largest contributor to the production cost. A sensitivity analysis was carried out to determine the effect of soybean oil prices on the process profitability.     

Comparison of ecological footprint for biobased PHA production from animal residues utilizing different energy resources

Realizing a sustainable development of our planet requires a reduction of waste production, harmful emissions, and higher energy efficiency as well as utilization of renewable energy sources. One pathway to this end is the design of sustainable biorefinery concepts. Utilizing waste streams as raw material is gaining great importance in this respect. This reduces environmental burden and may at the same time contribute to economic performance of biorefineries. This paper investigates the utilization of slaughtering waste to produce biodegradable polyesters, polyhydroxyalkanoates (PHA), via bioconversion. PHA are the target product while production of high quality biodiesel along with meat and bone meal (MBM) as by-products improves the economic performance of the process. The paper focuses on ecological comparison of different production scenarios and the effect of geographical location of production plants taking different energy production technologies and resources into account; ecological footprint evaluation using Sustainable Process Index methodology was applied. Keeping in mind that the carbon source for PHA production is produced from waste by energy intensive rendering process, the effect of available energy mixes in different countries becomes significant. Ecological footprint results from the current study show a bandwidth from 372,950 to 956,060 m²/t PHA production, depending on the energy mix used in the process which is compared to 2,508,409 m²/t for low density polyethylene.     

Design of biorefinery systems for conversion of corn stover into biofuels using a biorefinery engineering framework

Unlocking the potential and value of lignocellulosic residues is an important step in making biorefineries economically and environmentally promising. This calls for a holistic and systematic approach in designing sustainable industrial systems. In this work, biorefinery systems via biochemical route (acetone–butanol–ethanol or ABE system) and thermochemical route (gasification and mixed alcohols or GMA system) for converting corn stover into biofuels have been designed using a Sustainable Engineering Framework. The framework involves eight main steps: (1) design problem definition, (2) data collection, (3) process synthesis and simulation, (4) process integration, (5) resource recovery from residues, (6) utility system design, (7) economic and environmental modelling and (8) economic value and environmental impact margin analysis for decision making. Consideration of resource recovery from biorefinery waste streams has proven to be the key in making biorefineries self-sustaining and with low environmental impacts. Simultaneous economic and environmental feasibility assessment at the early stage of process design is highly envisaged. The cost of biofuel production in the ABE system has been found to be 49.2 US$/GJ and 69.9 US$/GJ in the GMA system. The greenhouse gas emissions are 46.2 g CO₂-eq/GJ for ABE and 19.0 g CO₂-eq/GJ for GMA, lower than gasoline (85 g CO₂-eq/GJ). The GMA system is not economically compelling though with high environmental benefit, while the ABE system has shown to be both economically and environmentally feasible.     

纤维素改性生物塑料聚羟基脂肪酸酯的研究进展

基于国内外的研究现状,综述了生物塑料聚羟基脂肪酸酯(PHAs)的改性方法以及纤维素改性生物塑料聚羟基脂肪酸酯复合材料的制备工艺。同时,针对每一种纤维素改性生物塑料聚羟基脂肪酸酯复合材料的制备工艺,具体分析了纤维素改性生物塑料聚羟基脂肪酸酯复合材料结构和性能的变化,指出了每种制备工艺的优缺点。纤维素改性生物塑料聚羟基脂肪酸酯复合包装材料将成为今后包装材料领域的研究重点,且实现绿色生产与进一步改善二者复合后的材料性能,将是实现产业化生产的关键。     

水泥生产中矿渣综合利用的环境负荷分析研究

本研究采用生命周期评价方法定量化利用矿渣生产水泥的环境影响潜力,并与硅酸盐水泥进行对比分析,据此辨识水泥生产中矿渣综合利用的环境热点与改进潜力。研究结果显示,利用矿渣生产水泥的环境负荷相对于硅酸盐水泥降低15％,同时可以避免矿渣处置造成的环境影响。此外,研究证明矿渣在水泥中利用的相关环节,生产过程燃煤燃烧的直接排放与消耗电力的间接排放是造成环境影响的主要来源。因此,降低水泥生产能耗与增加余热回收率是降低环境影响的最有效措施。根据分析,若能达到国际先进化水平15．6％的余热回收率,可进一步使水泥的环境负荷降低6％左右。     

木质素生物合成可降解包装材料聚羟基脂肪酸酯的研究进展

目的 通过对木质素生物合成聚羟基脂肪酸酯(PHAs)的研究,实现PHAs的低成本、规模化生产和木质素的高值化利用。方法 归纳分析现阶段国内外木质素降解菌及生物合成PHAs的主要菌种和目前存在的问题,介绍生物合成PHAs的木质素底物种类、合成过程中工艺优化策略的相关研究进展,同时总结PHAs在包装领域的相关应用。结果 木质素生物合成PHAs过程中,通过筛选木质素降解菌、培养PHAs合成菌、优化PHAs的合成工艺及影响因素,可有效提高木质素底物的转化率和PHAs的产量,从而降低生产成本。结论 木质素转化为PHAs的过程虽然面临着一些挑战,但随着技术的不断创新和生产工艺的优化,木质素为底物合成的绿色生物塑料PHAs在包装领域会有广阔的应用前景和发展空间,必将推动包装材料向绿色化、安全化方面发展。     

Sustainability assessment for biodiesel production via fuzzy optimisation during research and development (R&D) stage

Biodiesel is regarded as an important renewable fuel for meeting the global future energy demand and resolving the environmental problems (e.g. global warming). Despite its known advantages, it is still very critical to assess the sustainability of biodiesel production prior to greater expansion for commercialisation. Early hazard assessment when the process is still under development and design is very beneficial as process modifications to eliminate or reduce hazards can be made easier at lower costs. In this paper, inherent safety, health and environment (SHE) and economic performance (EP) analysis is conducted for biodiesel production during the earliest process lifecycle which is named as research and development (R&D) stage. Prior to the assessment, eight biodiesel production pathways via base-catalysed, acid-catalysed, enzymatic and supercritical transesterification using fresh or waste oil are classified. The inherent SHE assessments are conducted using the renowned methods of the Prototype Index of Inherent Safety (PIIS), Inherent Occupational Health Index (IOHI) and Inherent Environmental Toxicity Hazard (IETH) for inherent safety, health and environmental friendliness, respectively. The EP assessment is done using a proposed costing assessment based on operating cost and revenue. A systematic framework for assessing alternative biodiesel production pathways during the R&D stage is presented. Fuzzy optimisation approach is used to assess the pathway candidates based on multiple objectives of inherent SHE and EP. From the assessment result, it is found that biodiesel production based on enzymatic transesterification using waste oil is the most desirable pathway. Following the result of the assessments, several improvement actions for inherent SHE in biodiesel production are proposed and discussed.     

Utilization of flotation wastes of copper slag as raw material in cement production

Copper slag wastes, even if treated via processes such as flotation for metal recovery, still contain heavy metals with hazardous properties posing environmental risks for disposal. This study reports the potential use of flotation waste of a copper slag (FWCS) as iron source in the production of Portland cement clinker. The FWCS appears a suitable raw material as iron source containing >59% Fe(2)O(3) mainly in the form of fayalite (Fe(2)SiO(4)) and magnetite (Fe(3)O(4)). The clinker products obtained using the FWCS from the industrial scale trial operations over a 4-month period were characterised for the conformity of its chemical composition and the physico-mechanical performance of the resultant cement products was evaluated. The data collected for the clinker products produced using an iron ore, which is currently used as the cement raw material were also included for comparison. The results have shown that the chemical compositions of all the clinker products including those of FWCS are typical of a Portland cement clinker. The mechanical performance of the standard mortars prepared from the FWCS clinkers were found to be similar to those from the iron ore clinkers with the desired specifications for the industrial cements e.g. CEM I type cements. Furthermore, the leachability tests (TCLP and SPLP) have revealed that the mortar samples obtained from the FWCS clinkers present no environmental problems while the FWCS could act as the potential source of heavy metal contamination. These findings suggest that flotation wastes of copper slag (FWCS) can be readily utilised as cement raw material due to its availability in large quantities at low cost with the further significant benefits for waste management/environmental practices of the FWCS and the reduced production and processing costs for cement raw materials.     

变压吸附脱碳双高工艺的工业应用

主要介绍了变压吸附脱碳双高工艺的最新应用。装置运行中,针对合成氨、尿素生产的所需,对原料气有效组分CO2、H2、N2加以分离回收,CO2、H2、N2收率高、纯度高,真正体现了变压吸附双高技术的特点,并且相对于传统湿法脱碳而言,此工艺具有流程简单,自动化程度高,操作成本低,H2、N2、CO2的收率高,便于维护等优点。     

Aqueous two phase extraction—an environmentally benign technique

Aqueous two-phase extraction (ATPE) is basically a liquid–liquid extraction technique employing two aqueous phases comprising either two polymers or a polymer and a salt. In addition to the other advantages it offers, ATPE is gaining increasing popularity as an environmentally benign technique because (1) it does not employ volatile organic compounds as solvents, (2) it involves phase-forming polymers that rely on the structuring properties of liquid water not only for the formation of phase systems but also for solubilizing the otherwise relatively insoluble hydrophobic solutes, (3) it exploits the remarkable properties of polymers such as polyethylene glycols, polyvinyl pyrrolidone (PVP) etc. and (4) it makes use of phase-forming components which could be recovered and recycled to a limited degree. In some modified form, ATPE is finding application in environmental remediation. ATPE is discussed by considering case studies involving extraction of enzymes for waste treatment and recovery of valuable by-products from waste, extraction of useful components of plant origin and extraction of natural colours. The scope of ATPE in the context of pollution prevention or application for environmental remediation is discussed. Advantages/limitations of ATPE are also discussed. Barriers to a widespread industrial application of ATPE are examined and possible solutions suggested.     

Resources reduction in the fluorine industry: fluoride removal and recovery in a fluidized bed crystallizer

Crystallization process in a fluidized bed reactor (FBR) appears as an alternative clean technology to the conventional chemical precipitation process. Crystallization process in a FBR contributes to an environmental friendly production, because it allows reducing the waste production as well as recovery of materials. The aim of this work is to scale up the crystallization process in a FBR for the treatment of industrial fluoride wastewater. The technical viability of the process was concluded in agreement with the obtained results in laboratory scale, with fluoride recovery efficiencies in the reactor between 70 and 80% to form synthetic CaF₂, which is able to be recycled as raw material for the production of hydrofluoric acid.     

Inorganically filled starch based fiber reinforced composite foam materials for food packaging

 A process for the manufacture of highly inorganically filled starch based fiber reinforced foam composites for food-packaging use is described. Starch, obtained from potato, corn, or other sources, is used as binder to form net shape foam composite substrates under hydrothermal conditions. The starch content is 25 to 60 wt. % of the product. Ground calcium carbonate is the principal inorganic material, being 25 to 60 wt. % of the product. The composite substrate is foamed by steam at temperatures between 160° and 220°C in a single 15 to 200 seconds step within heated molds. The organic-inorganic composite is reinforced with 5 to 20 wt. % wood or plant fiber. The substrate is rendered functional with food and beverages by thin overlay coatings that provide moisture barrier properties and additional mechanical flexibility. The product is used to package dry and wet foods and meets required food packaging standards. The substrate biodegrades rapidly in the presence of sufficient moisture or microbes. An environmental life-cycle model and an economic model are described as the additional forces to a materials model for research, development and commercialization. The primary goal of this development is to provide disposable packaging materials from renewable resources that are low in cost, low in environmental impact, and meet commercial performance requirements. Received: 22 October 1998 / Reviewed and accepted: 23 October 1998     

Perspectives for the production of bioethanol from wood and straw in Austria: technical, economic, and ecological aspects

Bioethanol produced from lignocellulosic resources is a promising candidate for the replacement of fossil fuels. In this study, we aim to determine the perspectives to produce lignocellulosic ethanol in Austria. Technical, environmental and economic aspects are being considered. Thirteen biotechnological production concepts using the raw materials straw and softwood were established and simulated with the steady state flowsheeting software IPSEpro. Bioethanol production cost and greenhouse gas (GHG) emissions for each system were calculated based on mass and energy balances obtained from process simulation. The emission of GHGs along the entire bioethanol process chain (“from well to wheel”) are compared to two reference systems producing the same amounts of by-products. In all concepts, process heat and considerable amounts of the by-products electricity, heat, pellets, C5 molasses, or biomethane could be obtained from residual biomass. Compared to a reference system driven by fossil energy, GHG emissions can be reduced by up to 76%. The production cost of ethanol was found to between 0.66?€ and 0.94?€ per liter of gasoline equivalent. The type and amount of by-product influence technical, economic, and environmental performance significantly. Converting all straw and softwood available in Austria to ethanol would result in an annual production of 340?kt.     

Economic assessment system towards sustainable composting quality in the developing countries

Reduction of landfills and dealing with the waste are among the key elements of the cleaner production and advanced environment policy. Composting represents one of the cleaner technologies in diverting organic waste from landfill. However, it has not been commonly practised in the developing countries due to low economic feasibility and environmental issues that arise from the abuse of compost quality. There are a lack of product standards and an indication of compost quality to govern its market and application. In order to foster public confidence in compost utilisation and as much as possible offset the operating cost, an economic assessment system is needed to benchmark the quality of the compost at a reasonable cost. In this study, a set of composting parameters and their analysis have been reviewed and ranked following their total scores in terms of relation to the agronomic value, technical complexity and analysis cost. The parameters were selected based on different assessment criteria. An assessment system developed on the base of the decision analysis comprises minimal analyses needed to assess the compost quality. The cost savings results from the presented work are illustrated by four scenarios: Scenario 1 served as the baseline to include all the necessary analyses and the remaining three (Scenarios 2, 3 and 4) had been evaluated by the developed assessment system. It is shown that the cost to assess the compost quality was reduced from 17 to 84 % depending on the type of input material and composting performance. The highest cost saving based on the analysis of compost quality reaching 84 % was achieved by Scenario 4 where composting was carried out using the segregated food and landscape waste. The assessment system could be very useful for improving the compost utilisation towards sustainable composting in the developing countries.     

多晶硅生产中氢气的来源与净化

简述了多晶硅生产过程中氢气的几个来源,并比较了采用电解、裂解或工业尾气净化回收氢气作为多晶硅生产补充氢气来源的技术、经济性。提出了采用特定吸附剂,变压吸附净化回收可重复利用氢气的新方法。对比了几种氢气的净化回收技术的优势,认为采用变压吸附（PSA）氢气净化工艺过程最优,能耗最低,经济效益最好。     

Analysis of bioenergy production at different levels of integration in energy-driven biorefineries

In this paper, a techno-economic and environmental assessment is performed to compare the stand-alone process and biorefinery ways to produce biodiesel, ethanol and butanol as potential cases for bioenergy production using fresh fruit bunches as raw material. Different levels of integration are considered (e.g., mass and energy integration, non-conventional technologies) along with the analysis of the process scale to determine the economic profitability and environmental impacts of the proposed cases. The results demonstrated that the biodiesel production based on the biorefinery concept has a positive effect on the profitability of the stand-alone process at different scales. The economic results were compared with data reported in the literature. Furthermore, the life cycle analysis of the proposed cases suggested that the deployment of the biorefinery concept at different levels of integration in the oil palm supply chain reduced the environmental impact of the biodiesel production, which was selected as the hotspot of the evaluated cases.     

System modelling for economic raw material selection

A system simulation method for economic raw material selection is presented, based on a realistic example. The total cost considered in raw materials selection is deemed to include the basic raw material cost, the extra manufacturing cost due to the selection of the particular raw material, and the final product quality cost. These costs are systematically simulated for three typical areas of interest: for the purchasing operation, for the manufacturing process and for the final product quality acceptance by the customer.     

Turning Industrial Residues into Resources: An Environmental Impact Assessment of Goethite Valorization

Goethite is a metals-rich residue that occurs during zinc production. The feasibility of metal recovery from goethite has been demonstrated, but is not economically viable on an industrial scale. Therefore, goethite is landfilled with considerable economic costs and environmental risks. The goal of this study is to evaluate the environmental performance of a new valorization strategy for goethite residues from zinc production, with the aims of: ① recovering the valuable zinc contained in the goethite and ② avoiding the landfilling of goethite by producing a clean byproduct. The presented goethite valorization strategy consists of a sequence of two processes: ① plasma fuming and ② inorganic polymerization of the fumed slag. Plasma fuming recovers the valuable metals by fuming the goethite. The metals-free fumed slag undergoes a process of inorganic polymerization to form inorganic polymers, that can be used as a novel building material, as an alternative to ordinary Portland cement (OPC)-based concrete. Life-cycle assessment (LCA) is used to compare the environmental performance of the inorganic polymer with the environmental performances of equivalent OPC-based concrete. The LCA results show the tradeoff between the environmental burdens of the fuming process and inorganic polymerization versus the environmental benefits of metal recovery, OPC concrete substitution, and the avoidance of goethite landfilling. The goethite-based inorganic polymers production shows better performances in several environmental impact categories, thanks to the avoided landfilling of goethite. However, in other environmental impact categories, such as global warming, the goethite valorization is strongly affected by the high-energy requirements of the plasma-fuming process, which represent the environmental hotspots of the proposed goethite recycling scheme. The key elements toward the sustainability of goethite valorization have been identified, and include the use of a clean electric mix, more effective control of the fumed gas emissions, and a reduced use of fumed slag through increased efficiency of the inorganic polymerization process.