Applying a mathematical approach to improve the tire retreading process

Problem of waste treatment is very important for environment and the share of tires in this scope is high. The aim of this paper is to analyse retreading as one very interesting way of tires’ treatment. In practice, firms involved with commercial vehicles exploitation have to decide whether to retread used tires or not, depending on the number of retreadings of used tires and travelled distances after each retreading. An approach based on Bayesian networks is proposed as a tool for decision making support in tire retreading process. Analysis is performed on database of tires’ exploitation from a company of public passenger transportation and the statistical results are used as inputs to the proposed model. The results obtained according to the proposed model provide a good basis when it comes to making a decision whether to retread or not a used tire.     

Economic and policy instrument analyses in support of the scrap tire recycling program in Taiwan

Understanding the cost-effectiveness and the role of economic and policy instruments, such as the combined product tax-recycling subsidy scheme or a tradable permit, for scrap tire recycling has been of crucial importance in a market-oriented environmental management system. Promoting product (tire) stewardship on one hand and improving incentive-based recycling policy on the other hand requires a comprehensive analysis of the interfaces and interactions in the nexus of economic impacts, environmental management, environmental valuation, and cost-benefit analysis. This paper presents an assessment of the interfaces and interactions between the implementation of policy instruments and its associated economic evaluation for sustaining a scrap tire recycling program in Taiwan during the era of the strong economic growth of the late 1990s. It begins with an introduction of the management of the co-evolution between technology metrics of scrap tire recycling and organizational changes for meeting the managerial goals island-wide during the 1990s. The database collected and used for such analysis covers 17 major tire recycling firms and 10 major tire manufacturers at that time. With estimates of scrap tire generation and possible scale of subsidy with respect to differing tire recycling technologies applied, economic analysis eventually leads to identify the associated levels of product tax with respect to various sizes of new tires. It particularly demonstrates a broad perspective of how an integrated econometric and engineering economic analysis can be conducted to assist in implementing policy instruments for scrap tire management. Research findings indicate that different subsidy settings for collection, processing, and end use of scrap tires should be configured to ameliorate the overall managerial effectiveness. Removing the existing boundaries between designated service districts could strengthen the competitiveness of scrap tires recycling industry, helping to reduce the required levels of product tax and subsidy. With such initial breakthroughs at hand to handle the complexity of scrap tire recycling technologies, there remains unique management and policy avenues left to explore if a multi-dimensional solution is to be successful in the long run.     

Design of unsurfaced roads constructed with large-size shredded rubber tires: a case study

Stockpiles of scrap tires are serious fire hazard, public health hazard, and an environmental burden. The construction of road embankments, using tire shreds as a lightweight fill, can consume large quantities of scrap tires and has certain engineering benefits. All the previous research focused on small size tire shreds (3–6 in. size) in terms of its use in civil engineering applications and determination of the engineering/environmental properties. This research specifically focuses on large size tire shreds (12 in. size) and its direct comparison with the other sizes of the tire shreds to develop mechanistic-empirical practical design model and so that the use of tire shreds in road bases could be used on regular basis with enhanced reliability instead of on an empirical basis. The research also examines the potential environmental implications of the use of shredded rubber tires and the comparison of the short-term results with other long-term monitoring studies.     

Industrial waste to energy by circulating fluidized bed combustion

Industrial waste is a good resource from the viewpoint of efficient waste management. The vital need for energy utilization and environmental protection mean it is of interest to develop circulating fluidized bed combustion (CFBC) to burn solid wastes with low pollutant emissions. The paper presents some explanatory studies on waste-to-energy in a pilot scale CFCB facility. A series of combustion/incineration tests have been carried out for the industrial wastes: petroleum coke, waste tire and sludge cakes with various moisture contents. It seems that the CFBC has feed flexibility without modifying heat transfer equipments for energy recovery. In addition, the results of experimental tests demonstrate that gas emissions from waste incineration in CFBC can be well controlled under local regulation limits.At normal operation temperature in CFBC (approx. 800°C), the heat transfer coefficient between bulk bed and bed wall is on the order of 10² W/m^2° C, which is useful to estimate the energy recovery of waste combustion by CFBC. A practical and simple guide is proposed to estimate the energy recovery from waste combustion by CFBC, and to find maximum allowable moisture content of waste if there is to be any energy recovery without auxiliary fuel.     

废轮胎多孔隙消波结构物特性之初期研究

基于废旧轮胎再利用及研发简易且低廉的施工方法与维护成本,本研究以规则波水工模型试验研究提出应用于港口码头的多孔隙弹性帷幕的初步理念。利用模型车轮胎以模块化方式组装成弹性帷幕后安装于码头前壁,研究多种周期波浪作用及不同消波室纵深对波浪反射率的影响。实验结果表明,简单的单一消波室多孔隙弹性帷幕对短周期波浪的消波效果较显著,消波室纵深较大者反射率较低,但可能引致水体振荡,后续可再强化消波室的消能效果。未来如能妥善研究废旧轮胎应用于多孔隙弹性帷幕消波结构物的施工与维修方法,除可缓解废旧轮胎处理给环境带来的压力外,也提供一种可用于简易渔港的施工简单、维修容易且资源再利用的消能结构物,该工程技术亦可输出至发展中国家,符合可持续发展观。     

污水处理磷回收的研究进展

磷矿数量减少与含磷污水造成的水体富营养化问题对磷资源的可持续利用提出了迫切要求。从污水处理的不同环节回收磷并重新利用,是实现磷资源循环利用的有效途径。本文讨论了国内外磷回收技术的研究进展和应用实例,包括从含磷污泥和富磷污水中回收磷的工艺,并对磷回收的技术经济性进行了分析。     

炼化企业低温余热利用技术探讨＊

目前炼化企业有大量的低温余热需要回收,了解低温余热的来源、回收途径和技术,对提高低温余热利用效率十分重要。文章对炼厂低温余热的主要来源、利用途径和技术进行综合分析,提出炼厂低温余热回收利用的一些建议。     

A holistic framework for design of cost-effective minimum water utilization network

Water pinch analysis (WPA) is a well-established tool for the design of a maximum water recovery (MWR) network. MWR, which is primarily concerned with water recovery and regeneration, only partly addresses water minimization problem. Strictly speaking, WPA can only lead to maximum water recovery targets as opposed to the minimum water targets as widely claimed by researchers over the years. The minimum water targets can be achieved when all water minimization options including elimination, reduction, reuse/recycling, outsourcing and regeneration have been holistically applied. Even though WPA has been well established for synthesis of MWR network, research towards holistic water minimization has lagged behind. This paper describes a new holistic framework for designing a cost-effective minimum water network (CEMWN) for industry and urban systems. The framework consists of five key steps, i.e. (1) Specify the limiting water data, (2) Determine MWR targets, (3) Screen process changes using water management hierarchy (WMH), (4) Apply Systematic Hierarchical Approach for Resilient Process Screening (SHARPS) strategy, and (5) Design water network. Three key contributions have emerged from this work. First is a hierarchical approach for systematic screening of process changes guided by the WMH. Second is a set of four new heuristics for implementing process changes that considers the interactions among process changes options as well as among equipment and the implications of applying each process change on utility targets. Third is the SHARPS cost-screening technique to customize process changes and ultimately generate a minimum water utilization network that is cost-effective and affordable. The CEMWN holistic framework has been successfully implemented on semiconductor and mosque case studies and yielded results within the designer payback period criterion.     

Refrigeration waste heat utilization for drying applications: a review

ABSTRACT

Cold chain industry has a vast potential for waste heat recovery. It is a matter of importance for energy efficiency point of view, as global energy demand is increasing day by day. Ample amount of low-grade energy is either unutilized or underutilized. The heat rejected by a Heat pump or refrigeration system emerged as a promising solution for dehydration by utilizing low-grade waste heat despite higher investment. As compared to solar drying technology, heat pump drying evolved as a reliable method regarding better process control, energy efficiency, and quality of the product to be dried. Energy utilized through the refrigeration system’s waste/exhaust heat recovery in combination with or without renewable energy source enhances the overall efficiency of the system and also reduces the cost. This useful review investigated and compared the research findings of waste heat utilization through heat pump and from condenser of refrigeration system on laboratory, pilot as well as industrial scale for drying of various fruits, vegetables, and agro products. Various drying parameters like drying rate, moisture content, Specific Moisture Extraction Rate (SMER), Coefficient of Performance (COP), Exergy efficiency, and temperature as well as humidity conditions inside the drying chamber were also reviewed to promote the technological advancement of energy utilization by commercial cold storage waste heat recovery.     

Rubber tire life cycle assessment and the effect of reducing carbon footprint by replacing carbon black with graphene

This research utilizes real operating data from a tire plant operating in Central Taiwan to investigate the carbon footprint emissions (CO₂e) involved in producing the electric bicycle. The simulation results are based on the PAS 2050 standard using the SimaPro 7.3 software tool. Our results show the total carbon footprint emissions of 1.2-kg tire for the electric bicycle weighing 4.53-kg CO₂e, composed of 2.63-kg CO₂e from raw tire materials stage, 1.295-kg CO₂e from tire manufacturing stage, and 0.605-kg CO₂e from tire transport stage. An international certified organization, British Standard Institute (BSI), verified the accuracy of our results as 98.7%. We found that carbon emissions at the raw materials stage were higher than that for the other two stages – manufacturing and transportation. Carbon black was determined as the maximum source of carbon emissions at the raw material stage. To reduce the tire plant carbon emissions, this paper recommends using graphene to replace carbon black. Graphene has been reported by many researches to improve the properties of rubber products. From our simulation results, the carbon footprint emissions of 4.56-kg CO₂e of the origin tire plant uses 0.456-kg carbon black to produce 1.2-kg electric bicycle tires. This can be reduced to 4.29 (5.92%), 4.03 (11.62%), 3.75 (11.76%), and 3.49-kg CO₂e (23.46%) by using graphene to replace carbon black 25, 50, 75, and 100 wt% respectively. If we focus only on 0.456-kg carbon black producing 1.08-kg CO₂e, the reduced carbon footprint will be 0.812 (24.81%), 0.547 (49.35%), 0.28 (74.07%), and 0.0128-kg CO₂e (98.81%) by using graphene to replace carbon black 25, 50, 75, and 100 wt% respectively. From our analysis, graphene replacing carbon black can reduce carbon footprint. This has not been published previously and provides a direction for the tire plant to save carbon emissions.     

干旱区油田采油污水的处理及综合利用

我国西部干旱地区的塔里木盆地,有许多深居欧亚大陆腹地的大型油田,都地处水资源极其匮乏的地区,在油田的开发过程中的用水量和产水量都比较大,本文就采油过程中产生的采油污水的处理和综合利用问题作了探讨。     

新疆油田盆5气田放空气回收技术应用

新疆油田盆5气田采用分子筛对天然气处理站的放空气进行回收,介绍了分子筛的吸附原理、回收技术原理及工艺流程、净化脱水压力稳定安全措施等。通过优化破乳剂类型及注入量,净化脱水后的放空气满足回收利用要求。此项回收技术的利用,每年可减排废气5209.2×104m3,回收天然气约360×104m3,增加经济效益360万元。     

废旧电子电器产品资源化利用技术

介绍了废印制电路板处理及资源化技术、废旧冰箱无害化处理及资源回收技术、电视电脑拆解处理设备、废线缆资源回收生产线等四项废旧电子电器产品资源化利用技术的原理、工艺流程、技术特点及应用案例、经济和社会效益。     

废弃SCR催化剂回收利用项目建设格局的分析

阐述并分析了我国即将大量产生的烟气脱硝SCR废催化剂,及回收利用状况,列举出了适宜的SCR废催化剂回收利用项目建设格局模式。     

余热锅炉在绿色油田建设中的应用

余热锅炉的运用使得不同品级的能源可以得到充分合理的利用。中国石油塔里木油田公司在生产实践中,采用燃气发电机组—余热锅炉联合循环技术,用不能再发电的燃气尾气生产蒸汽,对天然气中蕴含的能量进行分级利用,实现了发电、供热双重效益,也降低了对周边环境的热污染。文章对该热电联合循环的工艺流程进行介绍,通过对燃气发电机组尾气的能量传递进行计算,用热力学原理进行分析,以期实现对使用余热锅炉后的热电联产经济性进行综合评价的目的。     

Grey relational analysis of an integrated cascade utilization system of geothermal water

With the drastic decrease in fossil resources and rapid deterioration of the global environment, the utilization of geothermal resources has been strongly advocated. The combination of heat, power, and cold utility generation is commonly used to increase the utilization efficiency of geothermal resources. In this study, an integrated cascade utilization system of waste geothermal water (ICUWGW) from a flash geothermal power plant in China is established to increase the utilization efficiency of geothermal water. The waste geothermal water leaving the power plant is proposed for further use in cascade for two-stage LiBr/H₂O absorption cooling, agricultural product drying, and residential bathing. Twelve candidate temperature schemes showing different inlet and outlet temperatures of every subsystem are proposed for the ICUWGW. Several criteria are selected for the evaluation and screening of the candidate schemes. Grey relational analysis incorporating analytic hierarchy process is conducted to screen the optimal temperature scheme for the ICUWGW to meet the comprehensive criteria of thermodynamics and economics. Results show that the optimal scheme features significant improvement in energy efficiency, exergy efficiency, and equivalent electricity generation efficiency compared with those of the current geothermal power plant. The investment payback time of the additional subsystems for cooling, drying, and bathing is 1.85 years. Exergy analysis is also conducted to determine the further optimization potential of the optimal ICUWGW. Sensitivity analysis of electricity price on the performance of the optimal ICUWGW is also performed.     

垃圾填埋气中微量挥发性有机物的净化技术

垃圾填埋气中存在的多种微量挥发性有机物(VOCS),既造成二次污染,影响了人类健康;又对填埋气的回收利用产生了不利影响。本文综述了几种VOCS常规净化技术的基本原理、优势及限制,介绍了几种新兴技术,并预期有效的联合工艺是净化填埋气中微量VOCs的研究方向。     

Sustainable pattern analysis of a publicly owned Material Recovery Facility in a fast-growing urban setting under uncertainty

Sustainable development goals are achievable through the installation of Material Recovery Facilities (MRFs) in certain solid waste management systems, especially those in rapidly expanding multi-district urban areas. MRFs are a cost-effective alternative when curbside recycling does not demonstrate long-term success. Previous capacity planning uses mixed integer programming optimization for the urban center of the city of San Antonio, Texas to establish that a publicly owned material recovery facility is preferable to a privatized facility. As a companion study, this analysis demonstrates that a MRF alleviates economic, political, and social pressures facing solid waste management under uncertainty. It explores the impact of uncertainty in decision alternatives in an urban environmental system. From this unique angle, waste generation, incidence of recyclables in the waste stream, routing distances, recycling participation, and other planning components are taken as intervals to expand upon previous deterministic integer-programming models. The information incorporated into the optimization objectives includes economic impacts for recycling income and cost components in waste management. The constraint set consists of mass balance, capacity limitation, recycling limitation, scale economy, conditionality, and relevant screening restrictions. Due to the fragmented data set, a grey integer programming modeling approach quantifies the consequences of inexact information as it propagates through the final solutions in the optimization process. The grey algorithm screens optimal shipping patterns and an ideal MRF location and capacity. Two case settings compare MRF selection policies where optimal solutions exemplify the value of grey programming in the context of integrated solid waste management.     

A CLOSED WATER REUSE SYSTEM FOR POWER PLANT COOLING AND DIGESTER HEATING1

ABSTRACT: A model consisting of closed water reuse and productive use of various types of wastes for energy generation is presented. The sewage after treatment would be used as the cooling water for power plants, and the condenser discharge therefrom be used as heating water for sludge digesters. The water is then purified for municipal water supply for continuous use. The advantages of this system are that water resources and energy are conserved while various types of wastes including waste heat are controlled. With a preliminary system analysis, it appears that the design for power plant based on the total heating value of wastes and digester capacity based on sewage sludge generation is feasible in terms of acquisition and full utilization of various types of wastes as generated in a single metropolitan area. The system as shown in this design is in balance among various factors such as the generation rate of municipal refuse, municipal sewage, waste heat in the condenser discharge, and raw sewage sludge.     

抚顺石化公司硫磺回收装置的扩建和改造

抚顺石化分公司石油三厂原有硫磺回收装置的处理能力已经不能满足生产的需要,2002年对硫磺回收装置进行了扩建和改造。该装置采用了一段高温转化、二级催化转化的克劳斯工艺,采用揝SR敾乖?吸收工艺处理尾气。扩能改造后,新增的尾气处理能力与硫磺回收能力相配套,排放的废气符合国家现行的环保标准。该装置工艺路线合理、可靠,硫回收率高。