全生命周期产品和过程模型集成技术研究

制造业的产品和过程集成技术体现在各个不同的层面,为此,研究了全生命周期产品和过程模型的集成技术。采用面向对象方法,构建全生命周期虚拟产品模型,对全生命周期的产品信息进行表达,并对全生命周期的涵义进行阐述。虚拟产品模型由实体对象和联系对象组成,它是一个动态模型,在产品全生命周期中不断进化。通过面向对象Petri网模型(OPN),描述产品全生命周期的各种过程。在虚拟产品模型和OPN模型的基础上重点讨论产品模型和过程模型的集成技术,并结合实例进行研究。产品和过程模型集成为产品信息的重用和追溯提供支持。     

Improved design for textile production process based on life cycle assessment

Clean Technologies and Environmental Policy - The textile industry has a high environmental impact, discharging significant amounts of industrial water, consuming high levels of energy, and...     

Effects of feedstocks on the process integration of biohydrogen production

Future production of hydrogen must be sustainable. To obtain it, renewable resources have to be employed for its production. Fermentation of biomasses could be a viable way. The process evaluated is a two-step fermentation to produce hydrogen from biomass. Process options with barley straws, PSP, and thick juice as feedstocks have been compared on the basis of process balances. Aspen Plus has been used to calculate mass and energy balances taking into account the integration of the process. Results show that the production of hydrogen as energy carrier is technically feasible with all the considered feedstocks and thanks to heat integration, second generation biomass (PSP and barley straws) are competitive with food crops (thick juice).     

Incorporation of engineering knowledge into the modeling process: a local approach

Process modelling is the foundation of developing process controllers for monitoring and improving process/system health. Modelling process behaviours using a pure empirical approach might not be feasible due to limitation in collecting large amount of data. Engineering models provide valuable information about processes’ general behaviours but they might not capture distinct characteristics in the particular process studied. Many recent publications presented various ideas of using limited experimental data to adjust engineering models for making them suitable for certain applications. However, the focuses there are global adjustments, where modification of engineering models impacts the entire model-application region. In practice, some engineering models are only valid in a part of experimental data domain. Moreover, many discrepancies between engineering models and experimental data are in local regions. For example, in a chemical vapour deposition process, at high temperatures a process may be described by a diffusion limited model, while at low temperatures the process may be described by a reaction limited model. To address these problems, this article proposes two approaches for integrating engineering and data models: local model calibration and local model averaging. Through the local model calibration, the discrepancies between engineering’s first-principle models and experimental data are resolved locally based on experts’ feedbacks. To combine models adjusted locally in some regions and also models required little adjustments in other regions, a model averaging procedure based on local kernel weights is proposed. The effectiveness of the proposed method is demonstrated on simulated examples, and compared against a well-known existing global-adjustment method.     

Assessment of dose during the life cycle of natural stone production

The environmental impact during the life cycle of natural stone production was studied. One of the points of interest was radiation. Natural stone samples from 23 quarries were surveyed for the radioactivity. One quarry was selected for a case study where the effective dose to the workers was assessed. The use of these stones in buildings was also evaluated with respect to the excess dose caused to the residents. According to the results the excess effective dose to the workers does not exceed 1 mSv a(-1) at the quarries. In buildings, all natural stones studied can be used safely as surfacing materials.     

From mine to refrigeration: a life cycle inventory analysis of the production of HFC-134a

A life cycle inventory analysis has been conducted for the production of HFC-134a (1,1,1,2-tetrafluoroethane, CH₂FCF₃)¹ through from basic raw materials (crude oil, natural gas, sulphur and fluorspar) to the pure product delivered to industrial customers. The analysis was based on real industrial operations in Japan, USA and UK. It showed that production required limestone, water and transition metal catalysts, in addition to the basic raw materials, and that the energy required to provide these raw materials in a form that can be used at the plants and to process them through intermediates into HFC-134a is the equivalent of 4.52 tonnes of CO₂ per tonne of product. Environmental releases associated with HFC-134a included waste salt brine (to the sea), mine tailings (mainly “country” rock landfilled at the mine) and small quantities of calcium sulphate and spent catalyst (both sent to landfill). In addition, greenhouse gases amounting to the equivalent of 2.1 tonnes of CO₂ per tonne of product were emitted to the atmosphere from the plants studied, an effect very much smaller than that estimated in previous studies mainly because the real release rates from current processes are very much less than those assumed in prior work. The global warming potential^{, 2} of HFC-134a is 1300, meaning that, during the first 100 years following the release of one tonne, the effect on climate change is equivalent to 1300 tonnes of carbon dioxide. Consequently, the 6.6 tonnes of carbon dioxide equivalent, emitted during production in the form of energy required and other greenhouse gases, is of relatively little importance and the key requirement to reduce environmental impact is containment during use.     

The integration of manufacturing and cost information into the engineering design process

In manufacturing systems engaged in the batch manufacture of discrete products, critical decisions on materials and processes are made during the design phase, decisions having significant impact on costs of production. A new computer aided design tool has been developed to enable product designers in small to medium size companies to incorporate manufacturability and cost criteria into their decision making. The paper describes the rationale of the system and its mode of operation. Experiments to validate its practicality and usefulness have yielded encouraging results.     

Assessment of bioenergy production from mid-rotation thinning of hardwood plantation: life cycle assessment and cost analysis

Forestry thinning logs, a low-value by-product of the forestry industry, present an opportunity for bioenergy production. It can be converted into solid, liquid, and gaseous fuels via different conversion techniques. Comparative life cycle assessment and life cycle costing (LCC) analysis were conducted to evaluate six options: woodchip gasification for power generation; wood pellets gasification in combined heat and power plant; wood pellet combustion for domestic water and space heating; pyrolysis for power generation; pyrolysis with bio-oil upgrading to transportation fuels; and ethanol production for transportation fuel mix. The functional unit used in this study was the treatment of 1 Mg of biomass. Global warming; acidification; eutrophication; fossil depletion, human toxicity; and land use impact categories were considered. The LCC also included greenhouse gas (GHG) emissions costs. The effects of uncertainties in the system on the overall performance of the scenarios were also evaluated. The results showed that all options except for ethanol production are GHG emission negative. Woodchips gasification performed best in all environmental impact categories and had the lowest LCC ($177.6/Mg). Biomass drying consumed more than 50% of the energy requirement for all options except for production of liquid transportation fuels via upgrading of pyrolytic oil, in which case the fuel upgrading process was the most energy intensive. In terms of energy return, all options, except electricity production through pyrolysis, offered positive return. The results highlight the importance of using biomass with least possible processing in order to maximise environmental and energy return and minimise LCC.     

Multidimensional life cycle assessment on various moulded pulp production systems

Moulded pulp has been used as an alternative to plastic in certain packaging applications, but some problems in the production system lead to higher costs including energy consumption. Industry tends to operate on the basis of experience rather than through scientific evaluation and systematic design methods. The research aims at detecting the problems in the production system by a multidimensional life cycle assessment (MLCA) with transparent analysis. The MLCA measures the performance of the moulded pulp production system with regard to technical, economic and environmental aspects and produces quantitative results (in monetary units), and finally indicates the overall efficiency of the production system using a sustainability index (SI). A life cycle impact assessment method based on endpoint modelling (LIME) is mainly adopted in the MLCA. Three existing moulded pulp production systems for industrial packaging in China were assessed in this study. The results show that the main environmental impacts of the three production systems are the atmospheric emissions and landfill waste; the drying stage in the production systems, which is dominated by consumption of resources and environmental impacts, is the key to controlling costs; steam should be the first preferred heat source in the drying process for achieving sustainability in the moulded pulp production system. The optimum for the three cases is identified by calculating the newly developed SI. The MLCA approach can be used to assist in identifying potential improvements and practical new packaging designs. Copyright © 2009 John Wiley & Sons, Ltd.     

Monotony analysis and sparse-grid integration for nonlinear chance constrained process optimization

The numerical solution of a nonlinear chance constrained optimization problem poses a major challenge. The idea of back-mapping as introduced by M. Wendt, P. Li and G. Wozny in 2002 is a viable approach for transforming chance constraints on output variables (of unknown distribution) into chance constraints on uncertain input variables (of known distribution) based on a monotony relation. Once transformation of chance constraints has been accomplished, the resulting optimization problem can be solved by using a gradient-based algorithm. However, the computation of values and gradients of chance constraints and the objective function involves the evaluation of multi-dimensional integrals, which is computationally very expensive. This study proposes an easy-to-use method for analysing monotonic relations between constrained outputs and uncertain inputs. In addition, sparse-grid integration techniques are used to reduce the computational time decisively. Two examples from process optimization under uncertainty demonstrate the performance of the proposed approach.     

Inventory and life cycle assessment of an Italian automotive painting process

Clean Technologies and Environmental Policy - In the current context of the European Environmental legislation and standards, the automotive sector is expected to continuously improve the vehicles...     

Environmentally friendly pathways for the evaluation of investment projects using life cycle assessment (LCA) and life cycle cost analysis (LCCA)

Issues related to improvement in the quality of products and to environmental protection in the economic policy of many countries and in the strategies of institutions and international organisations (e.g. European Union) have increased in importance in recent years as a consequence of the increase in environmental awareness of consumers. All these institutions currently recommend a comprehensive assessment of the effectiveness of planned projects during the decision-making process taking into account both economic and environmental factors. It is, therefore, important to develop methods and tools to assess environmental performance as a support to a proper choice of investment activities. The aim of this paper is to develop algorithms to link the life cycle assessment (LCA) model associated with environmental issues and the life cycle cost analysis (LCCA) model associated with economic factors to permit an integrated assessment of investment projects. The combination of LCA and LCCA results enables the assessment of ongoing or planned investments and should be used as a priority in making strategic decisions. In this paper, three environmentally friendly pathways (algorithms) using LCA–LCCA indicators as a support for decision-making processes were proposed: the first for implementing any environmental investments, the second for modernisation and innovation investments, and the third for new investments.     

New proposal for integrated production of sugar and biofuels from sugar beet

The problems related to the traditional technology of sugar-beet processing have became so important that the beet sector in Europe, and particularly in Italy, has been shocked. If we want to produce sugar beet in the future it is necessary to decrease the production costs through a simplification of the technology, a decreasing of the problems related to the energy and water consumptions, the elimination of the solid, liquid and gaseous wastes. We tried in the past to give our contribution for solving these problems but we have found difficulties in convincing the beet sugar world to drastically modify the traditional technology. The problems are so important that an European Project (TOSSIE—TOward Sustainable Sugar Industry in Europe) has the main object of disseminating the results of the research obtained in the last decades. We proposed different solutions including the elimination of calco-carbonic purification process, the utilization of membrane technology and suggesting different processing schemes. Now we would like to propose another possible solution with the elimination of the diffusion process and a balanced production, beside the crystallized sugar, of biofuels. Preliminary results obtained in laboratory and in a pilot plant will be presented and discussed. An erratum to this article can be found at     

Modelling and integration of customer flexibility in the order commitment process for high mix low volume production

With increasing product variety and dynamic demand fluctuation, manufacturing industry is moving towards a high product mix and low order volume production environment. Consequently, the order commitment process is becoming one of the most important processes for manufacturing firms to meet individual customer's needs with limited resources. However, demands for shortened delivery lead time, diverse customer requirements and more frequent customer orders have made the order commitment task more challenging. This paper attempts to tackle these new challenges by incorporating not only manufacturing flexibility but also flexibility from the demand side. Customer flexibility is characterised by customer indifference to certain product attributes and/or delivery schedules. Intuitively, with the consideration of customer flexibility, both manufacturers’ and customers’ interests can be better served since the solution space of matching demand and supply can be extended beyond the traditional domain purely from a manufacturing perspective. To this end, a systematic approach is developed to characterise and model customer flexibility. A mixed-integer-programming model is formulated to provide optimal order commitment decisions.     

A process systems framework for rapid generation of life cycle inventories for pollution control and sustainability evaluation

Life cycle assessment (LCA) is a tool that aids in sustainable decision-making among product and process alternatives. When implementing LCA, the efficient and accurate modeling of chemical processes for life cycle inventory (LCI) generation is still challenging. Challenges include a lack of systematic design and simulation tools and approaches to develop chemical process models for obtaining and analyzing more realistic LCI results. In this contribution, a novel process systems framework is proposed for estimating LCI results when implementing pollution control technologies. This framework involves the development and incorporation of pollution control unit (PCU) modules into process simulation and generation of LCI data associated with the PCUs for use in a sustainability evaluation. Different pollution control modules are designed for rapid LCI estimation and applied to obtain emissions, utility consumption, material, and land footprint results related to waste streams of a process simulation. Then, the LCI results are analyzed with the objectives of minimizing the environmental impact and utility consumption. The proposed framework is illustrated via a biomass/coal gasification process for syngas production with the end goal of acetic acid manufacturing. Results associated with this case study show that the developed framework can provide guidelines for sustainable decision-making based on generated LCI results.     

Optimal cycle time and production rate in a family production context with shelf life considerations

This paper considers the problem of determining the optimal production rate for each item and the optimalcycle time for the family of items in a family production context with restrictions on the shelf life of the various items in the family. An algorithm that determines the optimal production rate for all the items as well as the optimal cycle time is proposed. This is an improvement over the existing method by Silver (1995) that can determine the optimal production rate only for one item for which the shelf life constraint is binding. Examples are provided to illustrate the proposed method.     

Introduction of threat analysis into the land-use planning process

The subject of this paper is a method for introducing risk assessment into the land-use planning (LUP) process. Due to adaptations of the results of risk assessment, which are needed to make the risk assessment usable by land-use planners, we term the overall process threat analysis. The key features of the threat analysis can be summarised as follows. (i) It consists of three main steps. The first is determination of the threat intensity level of an accident, the second is analysis of the environmental vulnerability of the surroundings of an accident, and the third, integrating the previous two, is determination of a threat index in the accident impact zone. All three are presented in GIS based maps, since this is a common expression in LUP. (ii) It can and should be applied in the early stages of the LUP process. The methodology is illustrated by an example in the context of renewal of a land-use plan for the Municipality of Koper in Slovenia. The approach of threat analysis follows directions of the Article 12 of the Directive 96/82/EC of the European Commission (the Seveso II Directive).     

基于全寿命周期费用分析法的风管系统的选择

针对目前国内还没有一种有效的方法用于选择和评价风管系统的现状,提出采用全寿命周期费用分析法来选择和评价风管系统,并在实际工程中,采用该方法比较和分析国内4种常见风管系统的一次性投资、能耗费和维护费,重点对各风管的全寿命周期费用进行评估,认为酚醛铝箔复合风管的费用最低,是一种值得推广的风管系统。