Effect of material flows on energy intensity in process industries

Many energy-intensive process industries have complex material flows, which have a strong effect on the overall energy intensity of the final product (OEIF). This problem, however, has only been recognised qualitatively due to the lack of quantitative analysis methods. This paper presents an in-depth quantitative analysis of the effect of material flows on energy intensity in process industries. Based on the concept of a standard material flow diagram (SMFD), as used in steel manufacturing, the SMFD for a generic process industry was first developed. Then material flow scenarios were addressed in a practical material flow diagram (PMFD) using the characteristics of practical process industries. The effect of each material flow deviating from a SMFD on the OEIF was analysed. The steps involved in analysing the effect of material flows in a PMFD on its energy intensity are also discussed in detail. Finally, using 1999 statistical data from the Chinese Zhenzhou alumina refinery plant, the PMFD and SMFD for this plant were constructed as a case study. The effect of material flows on the overall energy intensity of alumina (OEIA) was thus analysed quantitatively. To decrease OEIA, the process variations which decrease the product ratios could be employed in all except in multi-supplied fraction cases. In these cases, the fractions from the stream with lower energy intensities should be increased.     

Energy conservation and circular economy in China's process industries

Since energy consumption in process industries accounts for a great proportion of China's total energy consumption, energy conservation becomes the practical choice to reduce the conflict between energy demand and energy supply in China, and therefore, promoting energy conservation is the long-term solution to China's energy and environment problems from the source. In this paper, based on the introduction of the concept of energy consumption status in China's key energy-consuming process industries, the main technical bottlenecks and resource-environment problems were analyzed with special emphasis on energy utilization efficiency, energy consumption mode, and waste emission. As for the measures to resolve these problems, at the policy level, policies and programs of Chinese government related to energy conservation were introduced in combination with China's circular economy structure. At the technical level, the key technologies and research progress to improve energy utilization efficiency, reducing energy consumption, as well as utilizing the resource of discharged wastes were reviewed. Finally, three typical cases of the development of circular economy at three levels, namely the chemical industry, metallurgical industry, and electric power industry, were studied for the enforcement of circular economy and energy conservation in China's process industries.     

Energy use,energy savings and emission analysis in the Malaysian rubber producing industries

In this paper an analysis of energy use and energy conservation in the Malaysian rubber producing industries is presented. It has been found that rubber industries consume a substantial amount of energy. Excessive use of energy is usually associated with many industrial plants worldwide, and rubber plants are no exception. This study is based on the realization that enormous potential exists for cost-effective improvements in the existing energy-using equipment. Through the method of a walkthrough energy audit, power rating, operation time of energy-consuming equipment/machineries and power factor were collected. The data were then analyzed to investigate the breakdown of end-use equipment/machineries energy use. The results of the energy audit in the Malaysian rubber and rubber producing industries showed that the electric motor accounts for a major fraction of total energy consumption followed by pumps, heaters, cooling systems and lighting. Since the electric motor takes up a substantial amount of the total energy used in rubber industries, energy-savings strategies such as the use of high efficient motors, and variable speed drive (VSD) have been used to reduce energy consumption of motors used in rubber industries. Energy-savings strategies for compressed-air systems, boilers, and chillers have also been applied to estimate energy and cost savings. It has been found that significant amount of energy and; utility bills can be saved along with the reduction of emission by applying the foretold strategies for energy using machineries in the rubber industries.     

Energy crop production costs in the EU

The objective of this study was to calculate indicative ranges of production costs and assess the main sources of cost for a number of energy crops, both annual and perennial, on a regional level in Europe. The production costs were calculated in terms of the economic compensation required by the farmer in order to grow the crop, and therefore include not only the cost of cultivation, but also the costs of land and risk, which are often omitted in production cost calculations. The cost of land was calculated as the opportunity cost based on the production of cereals. Thus, higher food prices lead to higher land costs, which in turn lead to higher energy crop production costs. The analysis was performed for three cases with different assumptions concerning yields and production cost reductions resulting from scale (total cultivation area in the region), and learning effects. The calculated energy crop production costs were found to be consistently lowest for short-rotation coppice (SRC) crops and highest for annual straw crops. The production costs of SRC crops were calculated to be about 4–5 € GJ⁻¹ under present conditions and 3–4 € GJ⁻¹ under improved future conditions. The production costs for perennial grasses were calculated to be about 6–7 € GJ⁻¹ and 5–6 € GJ⁻¹ under present and improved future conditions, respectively. The production costs for annual straw crops were estimated to be 6–8 € GJ⁻¹ under present conditions with small potential for cost reductions in the future.     

Energy efficiency in pumps

In this paper, “energy efficiency” studies, done in a big industrial facility’s pumps, are reported. For this purpose; the flow rate, pressure and temperature have been measured for each pump in different operating conditions and at maximum load. In addition, the electrical power drawn by the electric motor has been measured. The efficiencies of the existing pumps and electric motor have been calculated by using the measured data.

Potential energy saving opportunities have been studied by taking into account the results of the calculations for each pump and electric motor. As a conclusion, improvements should be made each system. The required investment costs for these improvements have been determined, and simple payback periods have been calculated.

The main energy saving opportunities result from: replacements of the existing low efficiency pumps, maintenance of the pumps whose efficiencies start to decline at certain range, replacements of high power electric motors with electric motors that have suitable power, usage of high efficiency electric motors and elimination of cavitation problems.     

Energy consumption,energy savings,and emission analysis in Malaysian office buildings

This paper is concerned with the estimation of energy use in office buildings in Malaysia and with the energy use of major equipment. Energy intensity (EI) – a measure of a building's energy performance – is estimated for Malaysia and compared with a number of selected countries. Air conditioners are shown to be the major energy users (57%) in office buildings, followed by lighting (19%), lifts and pumps (18%) and other equipment (6%). It is estimated that 77,569 MWh of energy can be saved and a huge reduction of emissions achieved through the application of advance glazing, compact fluorescent lamps (CFL), insulation, housekeeping, and by raising thermostat set point temperature of air conditioners, and reducing EI.     

Energy and emission analysis for industrial motors in Malaysia

The industrial sector is the largest user of energy in Malaysia. Industrial motors account for a major segment of total industrial energy use. Since motors are the principle energy users, different energy savings strategies have been applied to reduce their energy consumption and associated emissions released into the atmosphere. These strategies include using highly efficient motors, variable speed drive (VSD), and capacitor banks to improve the power factor. It has been estimated that there can be a total energy savings of 1765, 2703 and 3605 MWh by utilizing energy-efficient motors for 50%, 75% and 100% loads, respectively. It was also found that for different motor loads, an estimated US$115,936 US$173,019 and US$230,693 can be saved in anticipated energy costs. Similarly, it is hypothesized that a significant amount of energy can be saved using VSD and capacitor banks to reduce speed and improve the power factor, thus cutting energy costs. Moreover, a substantial reduction in the amount of emissions can be effected together with the associated energy savings for different energy savings strategies. In addition, the payback period for different energy savings strategies has been found to be reasonable in some cases.     

Energy demand and greenhouse gas emissions during the production of a passenger car in China

Rapidly-rising oil demand and associated greenhouse gas (GHG) emissions from road vehicles in China, passenger cars in particular, have attracted worldwide attention. As most studies to date were focused on the vehicle operation stage, the present study attempts to evaluate the energy demand and GHG emissions during the vehicle production process, which usually consists of two major stages—material production and vehicle assembly. Energy demand and GHG emissions in the material production stage are estimated using the following data: the mass of the vehicle, the distribution of material used by mass, and energy demand and GHG emissions associated with the production of each material. Energy demand in the vehicle assembly stage is estimated as a linear function of the vehicle mass, while the associated GHG emission is estimated according to the primary energy sources. It is concluded that the primary energy demand, petroleum demand and GHG emissions during the production of a medium-sized passenger car in China are 69,108 MJ, 14,545 MJ and 6575 kg carbon dioxide equivalent (CO₂-eq). Primary energy demand, petroleum demand and GHG emissions in China’s passenger car fleets in 2005 would be increased by 22%, 5% and 30%, respectively, if the vehicle production stage were included.     

Energy efficiency as a preferred resource: evidence from utility resource plans in the Western US and Canada

This article examines the future role of energy efficiency as a resource in the Western US and Canada, as envisioned in the most recent resource plans issued by 16 utilities, representing about 60% of the region’s load. Utility and third-party-administered energy-efficiency programs proposed by 15 utilities over a 10-year horizon would save almost 19,000 GWh annually, about 5.2% of forecast load. There are clear regional trends in the aggressiveness of proposed energy savings. California’s investor-owned utilities (IOUs) had the most aggressive savings targets, followed by IOUs in the Pacific Northwest, and the lowest savings were proposed by utilities in Inland West states and by two public utilities on the West Coast. The adoption of multiple, aggressive policies targeting energy efficiency and climate change appears to produce sizeable energy-efficiency commitments. Certain specific policies, such as mandated energy savings goals for California’s IOUs and energy-efficiency provisions in Nevada’s Renewable Portfolio Standard, had a direct impact on the level of energy savings included in the resource plans. Other policies, such as revenue decoupling and shareholder incentives and voluntary or legislatively mandated greenhouse gas emission reduction policies, may have also impacted utilities’ energy-efficiency commitments, though the effects of these policies are not easily measured. Despite progress among the utilities in our sample, more aggressive energy-efficiency strategies that include high-efficiency standards for additional appliances and equipment, tighter building codes for new construction and renovation, as well as more comprehensive ratepayer-funded energy-efficiency programs are likely to be necessary to achieve a region-wide goal of meeting 20% of electricity demand with efficiency in 2020.

Energy policy and the privatization of the UK energy industries

This article considers a number of issues arising from or associated with the UK government's policy of privatization/liberalization of the public sector industries in relation to the formulation and implementation of energy policy. The analysis presented suggests that, if the policy of privatization progresses very far, there may be a change in the weights attached to various instruments used for the implementation of energy policy.     

Energy savings and emissions reductions for rewinding and replacement of industrial motor

Electric motors consume 30-80% of total industrial energy around the world. This study estimates the economic viability of replacing rewound and standard motors with high efficiency motors (HEMs) in the industrial sector. The efficiency of a motor is degraded when it is rewound and it is better to rewind a larger motor compared with a smaller motor. It was found that a HEM can save on average 5.5% of energy compared with a standard motor. In addition, the payback period was found to be reasonable when a motor is operated at a 50% load. HEMs will also save a sizeable amount of energy and reduce emissions. It was estimated that 67,868 MWh/year energy and US$ 4,343,531 per year could be saved by introducing HEMs. By contrast, 44,582 tons of CO₂, 333 tons of SO₂ and 122 tons of NO_x emissions could be reduced through the aforementioned energy savings. This study found that rewound motors of a larger size and HEMs are economically viable.     

Assessing the sustainability challenges for electricity industries in ASEAN newly industrialising countries

Rapid social and economic progress in fast developing countries such that among the countries in the Association of Southeast Asian Nations (ASEAN) have driven substantial growth in electricity consumption in this region. Whilst this represents significant societal and economic development, it has potentially growing adverse environmental impacts. This raises a concern on sustainable development in the electricity sector in this region. This study evaluates key sustainability challenges in the electricity industries in the five largest energy consumers in ASEAN: Indonesia, Thailand, Malaysia, the Philippines and Vietnam. The 3A's energy sustainability objectives: Accessibility, Availability and Acceptability are used as the sustainability analytical framework. This study also draws together a set of associated indicators and criteria within the analytical framework to analyse the status of the electricity industries in these countries. The analysis shows that key sustainability challenges in the ASEAN-5 are attributable to satisfying rapid demand growth; enhancing security of electricity supply; and mitigating the increase in CO₂ emissions from electricity generation. Given the promising resource and technical potential in this region, renewable energy emerges as a favourable option to address these challenges; however, increasing the share of renewable energy in electricity generation requires considerable policy support. This study suggests that there is an opportunity for the ASEAN countries to strengthen regional collaborations through experience and resource sharing to enhance sustainability in the electricity industries. This study also highlights some of the key issues facing the electricity industry, and the need for new generation investment decision support tools which can address these issues.     

Energy,exergy and economic analysis of industrial boilers

In this paper, the useful concept of energy and exergy utilization is analyzed, and applied to the boiler system. Energy and exergy flows in a boiler have been shown in this paper. The energy and exergy efficiencies have been determined as well. In a boiler, the energy and exergy efficiencies are found to be 72.46% and 24.89%, respectively. A boiler energy and exergy efficiencies are compared with others work as well. It has been found that the combustion chamber is the major contributor for exergy destruction followed by heat exchanger of a boiler system. Furthermore, several energy saving measures such as use of variable speed drive in boiler's fan energy savings and heat recovery from flue gas are applied in reducing a boiler energy use. It has been found that the payback period is about 1 yr for heat recovery from a boiler flue gas. The payback period for using VSD with 19 kW motor found to be economically viable for energy savings in a boiler fan.     

Energy auditing kit for cement industries

Energy is now a costly and scarce commodity in any manufacturing industry, and hence, it is essential for each industry to develop an energy auditing kit to find the energy conservation opportunities and methods to reduce energy consumption. Such energy auditing would be unique, depending on the type and need of the specific industry. The auditing kit needs essential tools such as (i) subdivision of the production system of any commodity in several blocks or departments and (ii) a reliable metering or measurement system in each block. The reasons to have the subdivision or smaller pockets of a particular stage of production is to pinpoint the location of the higher energy consumption where greater attention is needed. The reasons to have a suitable metering system is to provide data for the energy audit, allow proper distribution of electrical energy costs to individual departments and to provide historical data on which performance evaluation can be done.     

Energy savings certificates: A market-based tool for reducing greenhouse gas emissions

Energy savings certificates (ESCs) are potentially a major tool that can be used by regulators and policy makers in reducing greenhouse gas (GHG) emissions. In this paper, we present our findings on the experience to date with ESCs, outline potential program opportunities in the US, and conclude with our perspective on how to proceed with the use of ESCs, particularly as a component of GHG reduction programs.     

Polygeneration and efficient use of natural resources

The consumption of natural resources has been increasing continuously during recent decades, due to the growing demand caused by both the economic and the demographic rise of global population. Environmental overloads that endanger the survival of our civilization and the sustainability of current life support systems are caused by the increased consumption of natural resources—particularly water and energy—which are essential for life and for the socio-economic development of societies. While not yet well utilized, process integration and polygeneration are promising tools which reach the double objective of increasing the efficiency of natural resources, and also minimizing the environmental impact. This paper discusses the concepts of polygeneration and energy integration and various examples of polygeneration systems: (i) sugar and energy production in a sugarcane factory; (ii) district heating and cooling with natural gas cogeneration engines and (iii) combined production of water and energy. It is clearly evident that polygeneration systems which include appropriate process integration significantly increase the efficient use of natural resources.     

胶合板生产能耗指标的确定及节能措施

文中介绍了胶合板生产的状况及合理确定胶合板生产综合能耗指标的重要性,详细阐述了胶合板生产能耗的计算方法和修正系数;制定胶合板生产能耗定额,不仅是检验和衡量胶合板企业技术工艺和管理水平的重要基础,也是规范和促进企业不断创新,加强管理和积极研究采纳新技术、新工艺、新设施的必要手段。对加强胶合板企业能源管理、提高企业的能源利用效率以及减少能源的浪费等具有一定的参考价值。     

Analysis of electrical motors load factors and energy savings in an Indian cement industry

Electric motors consume in between 30% and 80% of the total industrial energy use for few selected countries around the world. It was identified that many motors are operated under loaded conditions. In some cases, motors are operated even at 3-16% of their full loads. These low loads can be optimized with the application of variable speed drives (VSD) to match the load requirements. Based on the estimation, it has been found that annually about 1,865,925 MWh of energy can be saved for 60% speed reduction when VSDs are used. It was also found that about 2,122,675 tons CO₂emission could be avoided annually by using VSDs for Low Tension (LT) motors for 60% speed reduction. It was also estimated that annually about 4,600,386 MWh of energy can be saved for High Tension (HT) motors for 60% speed reduction using VSDs. The average payback period (PBP) for implementing VSDs for LT and HT motors found to be very low (i.e. about 2 days). In this particular study it is observed that installing both LT and HT capacitors to improve power factor found to be not economically viable owing to low level of energy savings.     

Energy conservation : An elasticity of substitution approach

Long-term forecasts of demand, used in energy planning, are based on assumptions alleged to be reasonable at the time of projections. The political debate can then focus on whether these assumptions are indeed reasonable. Common considers two sets of projections, and estimates the implicit price and income elasticities, thereby translating assumptions entailed in two different reports into concepts which are directly comparable. It is argued here that this approach need be taken a step further and elasticities of substitution between energy and other inputs should be calculated. Possibilities of energy conservation could then be taken into account.