Guangdong Dapeng LNG cold energy utilization-C_2++ extraction process integration

This paper makes a study of some technical and engineering aspects by using C2 ＋ hydrocarbon separation facility at Guangdong Dapeng liquefied natural gas （GDLNG） terminal. In the C2＋ hydrocarbon extraction process, the cold energy contained in LNG will be utilized. In order to ensure the optimum operating conditions of the temlinal and C2 ＋ hydrocarbon extraction facility by optimizing the current operating processes of the terminal, the C2 ＋ hydrocarbon extraction facility construction plan is proposed. We conducted numerous calculations and simulations using such specific analysis software as PRO II 〈 version 7.0 〉. Additionally available flow data are used to verify the cyclic send-out rates from the terminal, thus establishing the current and future projected load factors. This study is intended to make sure that GDLNG can continue to supply gas via the pipeline system safely without interruptions and most significantly solves the effects of flow fluctuations at the terminal gasification send-out facility on the hydrocarbons extraction, ensuring optimum pipeline operations and ensuring safe and effective means for such C2＋ hydrocarbons extraction process as well. At the same time, the terminal is also in the optimum operation condition. This is very significant to the terminal safety operation and the energy conservation and emission reduction.

Process simulation and energy integration in the mineral carbonation of blast furnace slag

Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste heat.The mineral carbonation of BF slag can not only reduce emissions of solid waste but also realize the in-situ fixation of CO_2 with low energy consumption if integrated with the waste heat utilization.In this study, based on our previous works, Aspen Plus was employed to simulate and optimize the carbonation process and integrate the process energy.The effects of gehlenite extraction, MgSO_4 carbonation,and aluminum ammonium sulfate crystallization were studied systematically.The simulation results demonstrate that 2.57 kg of BF slag can sequester 1 kg of CO_2, requiring 5.34 MJ of energy(3.3 MJ heat and 2.04 MJ electricity), and this energy includes the capture of CO_2 from industrial flue gases.Approximately 60 kg net CO_2 emission reduction could be achieved for the disposal of one ton of BF slag.In addition, the by-product,aluminum ammonium sulfate, is a high value-added product.Preliminary economic analysis indicates that the profit for the whole process is 1127 CNY per ton of BF slag processed.

Study of Total Process Energy Integration

The energy utilization consistency method in process integration extracts the key component of process energy utilization, and simplifies the procedure of process analysis and integration. The method allows the conversion of the total process energy integration into a synthesis problem of a pseudo-heat exchanger network. The advantages of using the energy utilization consistency and the pseudo-temperature methods are presented by two examples of integration of large-scale complex processes. The improved genetic algorithm is proved to be an effective tool in the retrofitting procedures.

Optimal Size for Maximal Energy Efficiency in Information Processing of Biological Systems Due to Bistability

Energy efficiency is closely related to the evolution of biological systems and is important to their information processing. In this work, we calculate the excitation probability of a simple model of a bistable biological unit in response to pulsatile inputs, and its spontaneous excitation rate due to noise perturbation. Then we analytically calculate the mutual information, energy cost, and energy efficiency of an array of these bistable units. We find that the optimal number of units could maximize this array＇s energy efficiency in encoding pulse inputs, which depends on the fixed energy cost. We conclude that demand for energy efficiency in biological systems may strongly influence the size of these systems under the pressure of natural selection.

Optimizing Power Plant Thermal System Design Using "Process Energy Integration" Method

The paper presents a renovation of thermal system design of a power and heat cogeneration device by utilizing the "Process Energy Integration Method". The new alternative obtains prominent energy saving result.

Identification of time-varying system and energy-based optimization of adaptive control in seismically excited structure

The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures.While synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive control.In this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are integrated.First,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)method.Then,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be operational.Optimization is also performed based on the probability density function of the energy under the seismic excitation at any time.Finally,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed approach.The simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.

Towards Production and Energy Coupling System Modeling and Simulation for Energy Optimization in the Process Industry

The production and energy coupling system is used to mainly present energy flow, material flow, information flow, and their coupling interaction. Through the modeling and simulation of this system, the performance of energy flow can be analyzed and optimized in the process industry. In order to study this system, the component based hybrid Petri net methodology (CpnHPN) is proposed, synthesizing a number of extended Petri net methods and using the concept of energy place, material place, and information place. Through the interface place in CpnHPN, the component based encapsulation is established, which enables the production and energy coupling system to be built, analyzed, and optimized on the multi-level framework. Considering the block and brief simulation for hybrid system, the CpnHPN model is simulated with Simulink/Stateflow. To illustrate the use of the proposed methodology, the application of CpnHPN in the energy optimization of chlorine balance system is provided.

Fish Processing and Its Energy Dynamics in Zambia

This study presents field data and results on local fish processing, its energy supply, and consumption in the Northern Province of Zambia. The study also evaluates the impact of processing conditions on fish quality and cost for the different processing systems available in the selected communities. The result shows that fuelwood is the primary source of energy for fish processing used either in a modified three-stone fire (MTSF) system or a recently developed kiln. The charcoal smoking alternative had the least fuel consumption, yet was not considered as the preferred option due to the high cost of the fuel, a smaller quantity of fish processed per batch and longer processing time. The result also revealed that irrespective of the system used, the type of fish being processed and the pre-smoking drying time had a significant impact on the total energy consumption. Overall, the smoking kiln was found to increase the quantity of fish processed by five folds, reduce fuel use by 48% and reduce the overall smoking time per kilogram fish processed by 39%. A relatively higher fish quality was obtained with the use of the smoking kiln in comparison with the MTSF and the charcoal smoking system. The use of the smoking kiln as a fish processing system is recommended because it improves the quality of the fish, can scale up fish processing due to its capacity and reduces energy use with its associated costs.

Relative importance of different physical processes on upper crustal specific heat flow in the Eifel-Maas region, Central Europe and ramifications for the production of geothermal energy

We study the recent upper crustal heat flow variations caused by long-term physical processes such as paleoclimate, erosion, sedimentation and mantle plume upwelling. As specific heat flow is a common lower boundary condition in many models of heat en fluid flow in the Earth’s crust we quantify its long-term transient variation caused by paleoclimate, erosion or sedimentation, mantle plume upwelling and deep groundwater flow. The studied area extends between the Eifel mountains and the Maas river inCentral Europe. The total variation due to these processes in our study area amounts to tectonic events manifested in the studied area 20 mW/m2, about 30% of the present day specific heat flow in the region.

Risk Assessment of Distributed Energy System Based on Fuzzy Analytic Hierarchy Process

Risk assessment of distributed energy system often has uncertainty and subjective problems. The problems will have some impact on the results. To solve the problems, a method of improved fuzzy analytic hierarchy process is proposed. By using the fuzzy analytic hierarchy process method, a hierarchical analysis model is established. And then according to the given judgment matrix of each index layer, we calculate whether it meets the consistency condition. And then if the judgment matrix does not meet the consistency condition, the problem will be solved by the improving of particle swarm optimization (PSO) with Kalman filter. The practice in the distributed energy system shows that the method can not only fully reflect the fuzziness of assessment elements and process, but also reduce the influence of individual subjective factors and better evaluation results can be achieved.

Studying the variable energy band structure for energy storage materials in charge/discharge process

So far,a clear understanding about the relationship of variable energy band structure with the corresponding charge-discharge process of energy storage materials is still lacking.Here,using optical spectroscopy(red-green-blue(RGB)value,reflectivity,transmittance,UV-vis,XPS,UPS)to studyα-Co(OH)_(2) electrode working in KOH electrolyte as the research object,we provide direct experimental evidence that:(1)The intercalation of OH-ions will reduce the valence/conduction band(VB and CB)and band gap energy(Eg)values;(2)The deintercalation of OH-ions corresponds with the reversion of VB,CB and E_(g) to the initial values;(3)The color of Co(OH)_(2) electrode also exhibit regular variations in RGB value during the charge-discharge process.

PHOENIX’S FIRST NET-ZERO ENERGY OFFICE RETROFIT: A GREEN AND LEAN CASE STUDY

Many in the construction industry view lean practices as a means for reducing cost and schedule while maintaining or improving quality. This paper argues that lean practices can also be used to promote energy savings throughout a building’s life cycle. This paper presents a case study of an existing building retrofit in Phoenix, Arizona. The project owner, a general contractor, self-performed much of the building construction and worked to ensure the project team aligned around the project’s net-zero energy goal. All building systems, excepting the walls and roof, were re-designed and re-constructed. After retrofit, the building has achieved net-zero energy consumption;that is, the building produces as much energy as it consumes on an annual basis. Deep building energy retrofits typically result in larger energy savings than operational changes alone can provide, as these retrofits take a whole-building approach to design (i.e., optimize the whole) and implement integrated project delivery methods (e.g., (AIA, 2007)). This paper discusses a net-zero energy retrofit and how lessons learned on this project could apply to other deep energy retrofits for commercial buildings (where “deep” refers to energy savings of 25% or more) that may significantly improve building value (Miller and Pogue, 2009). The inefficiency of existing building stock supports the need for retrofitting: energy consumption in the existing building stock in the United States accounts for approximately 41% of the total primary energy consumption (US DOE, 2012). In order to reduce this consumption, existing buildings must be retrofit, through replacement or upgrade of their existing building systems, to improve their energy performance. Beyond the energy motivation, a building’s operating costs account for the largest portion of the life cycle cost. Thus, deep energy retrofit projects offer an opportunity to significantly reduce both national energy consumption and expenditures. While much research exists on the topic of energy retrofits, very little explores the role of the contractor. This paper explores the contractor’s role (rather than the designer’s or engineer’s role) in delivering deep energy retrofit projects. The contractor plays a critical role in delivering a project that meets the owner’s expectations and goals and satisfies the specifications (Ahn and Pearce, 2007). Namely, the contractor executes the plans and specifications, giving physical reality to the design team’s vision. In the case of deep energy retrofits, this role is particularly important, as installation and operation must conform to the design intent to achieve the predicted energy performance. Moreover, the contractor must understand the existing condition to effectively retrofit the building. This paper explores critical building energy efficiency measures and processes for achieving deep energy savings in retrofit projects. Specifically, we present the role of the contractor in a case study project in Phoenix, Arizona where the contractor was engaged in the project early in the design stage. This paper discusses the process of developing and selecting energy efficiency measures (EEMs). It explains the reasons for choosing particular EEMs, including a discussion of selecting an appropriate baseline for energy savings calculations, and documents the impact of EEMs on total energy consumption and design intent. The paper concludes with a discussion of recommendations that, if applied in part or whole, will increase the effectiveness of future construction teams in delivering deep energy retrofit projects.

A novel method based on entransy theory for setting energy targets of heat exchanger network

A T-Q diagram based on entransy theory is applied to graphically and quantitatively describe the irreversibility of the heat transfer processes.The hot and cold composite curves can be obtained in the T-Q diagram.The entransy recovery and entransy dissipation that are affected by temperature differences can be obtained through the shaded area under the composite curves.The method for setting the energy target of the HENs in T-Q diagram based on entransy theory is proposed.A case study of the diesel oil hydrogenation unit is used to illustrate the application of the method.The results show that three different heat transfer temperature differences is 10 K,15 K and 20 K,and the entransy recovery is 5.498×10~7k W·K,5.377×10~7k W·K,5.257×10~7k W·K,respectively.And the entransy transfer efficiency is 92.29%,91.63%,90.99%.Thus,the energy-saving potential of the HENs is obtained by setting the energy target based on the entransy transfer efficiency.

Efficient Energy Optimized Faithful Adder with Parallel Carry Generation

Abstract:Approximate computing has received significant attention in the design of portable CMOS hardware for error-tolerant applications.This work proposes an approximate adder that to optimize area delay and achieve energy efficiency using Parallel Carry(PC)generation logic.For‘n’bits in input,the proposed algorithm use approximate addition for least n/2 significant bits and exact addition for most n/2 significant bits.A simple OR logic with no carry propagation is used to implement the approximate part.In the exact part,addition is performed using 4-bit adder blocks that implement PC at block level to reduce node capacitance in the critical path.Evaluations reveal that the maximum error of the proposed adder confines not more than 2n/2.As an enhancement of the proposed algorithm,we use the Error Recovery(ER)module to reduce the average error.Synthesis results of Proposed-PC(P-PC)and Proposed-PCER(P-PCER)adders with n-16 in 180nm Application Specific Integrated Circuit(ASIC)PDK technology revealed 44.2%&41.7%PDP reductions and 43.4%&40.7%ADP reductions,respectively compared to the latest best approximate design compared.The functional and driving effectiveness of proposed adders are examined through digital image processing applications.

Energy consumption hierarchical analysis based on interpretative structural model for ethylene production

Interpretative structural model(ISM) can transform a multivariate problem into several sub-variable problems to analyze a complex industrial structure in a more efficient way by building a multi-level hierarchical structure model. To build an ISM of a production system, the partial correlation coefficient method is proposed to obtain the adjacency matrix, which can be transformed to ISM. According to estimation of correlation coefficient, the result can give actual variable correlations and eliminate effects of intermediate variables. Furthermore, this paper proposes an effective approach using ISM to analyze the main factors and basic mechanisms that affect the energy consumption in an ethylene production system. The case study shows that the proposed energy consumption analysis method is valid and efficient in improvement of energy efficiency in ethylene production.

Indicator system of energy efficient technologies evaluation of residential buildings in hot summer and cold winter regions of China

The related existing energy saving index system of buildings is deficient in direction, index coverage, depth, and technological and economic considerations. Aiming at the deficient existing research and with the advancement of energy saving of buildings in China from northern heating regions to southern hot summer and cold winter regions, selecting residential buildings in hot summer and cold winter regions as the research object, and through much evaluation index reference and repeated demonstrations and the borrowing of literature research home and abroad and relevant energy saving standards, filters and eliminates energy efficient technologies evaluation indexes according to the design principle of index system, the factors influencing the energy saving of residential buildings are evaluated, index system weight is established by adopting analytic hierarchy process, and finally the evaluation index system of energy saving technologies of residential buildings in hot summer and cold winter area of China is established. Each target layer includes five standard layer indexes and sixteen index layer indexes. The standard layer of evaluation index, namely primary indexes, includes the technological, energy saving effect, economic, environmental, and social indexes. The secondary indexes are selected based on the principles of concision, comprehensiveness, representativeness and operability.

Optimization of Distributed Integrated Multi-energy System Considering Industrial Process Based on Energy Hub

As a typical scenario of distributed integrated multi-energy system(DIMS),industrial park contains complex production constraints and strong associations between industrial productions and energy demands.The industrial production process(IPP)consists of controllable subtasks and strict timing constraints.Taking IPP as a control variable of optimal scheduling,it is an available approach that models the IPP as material flow into an extension energy hub(EH)to achieve the optimization of industrial park.In this paper,considering the coupling between the production process and energy demands,a model of IPP is proposed by dividing the process into different adjustable steps,including continuous subtask,discrete subtask,and storage subtask.Then,a transport model of material flow is used to describe the IPP in an industrial park DIMS.Based on the concept of EH,a universal extension EH model is proposed considering the coupling among electricity,heat,cooling,and material.Furthermore,an optimal scheduling method for industrial park DIMS is proposed to improve the energy efficiency and operation economy.Finally,a case study of a typical battery factory is shown to illustrate the proposed method.The simulation results demonstrate that such a method reduces the operation cost and accurately reflects the operation state of the industrial factory.

Estimation of Energy Consumption in COREX Process Using a Modified Rist Operating Diagram

Fuel consumption in the COREX-3000 process run in Baosteel is currently higher than the design index. Therefore, mass and heat balance equations for the COREX process were established using the basic principles in- cluded in the Rist operating diagram for blast furnace （BF） as a reference. Thermodynamic calculations were then used to modify the Rist operating diagram so that it was suitable for the COREX process. The modified Rist operating dia- gram was then applied for the evaluation of metallization rate （MR） and fuel structure to reduce the energy consump- tion in the COREX process. The modified Rist operating diagram for the shaft furnace （SF） provided a nearly ideal value for the restriction point W when the metallization rate was increased, while the point P on the operating line for the melter gasifier （MG） moved upward due to reduction in the heat required in hearth. The feasibility of reduc- ing the energy consumption during the COREX process by changing the fuel structure was also demonstrated.

An input-output model for energy accounting and analysis of industrial production processes： a case study of an integrated steel plant

To promote sustainability, it has become increasingly vital to properly account material and energy flows in industrial production processes. Therefore, a generic process-level input-output （IO） model was developed to provide an integrated energy （material） accounting and analysis approach for industrial production processes. By extending the existing processlevel IO models, the production, usage, export and loss of by-products were explicitly considered in the proposed IO model. Moreover, the by-products allocation procedures were incorporated into the proposed IO model to reflect individual contributions of products to energy consumption. Finally, the proposed model enabled calculating embodied energy of main products and total energy consumption under hierarchical accounting scope. Plant managers, energy management consultants, governmental officials and academic researchers could use this input-output model to account material and energy flows, thus calculating energy consumption indicators of a production process with their specific system boundary requirements. The accounting results could be further used for energy labeling, identifying bottlenecks of production activities, evaluating industrial symbiosis effects, improving materials and energy utilization efficiency, etc. The model could also be used as a planning tool to determine the effect that a particular change of technology and supply chains may have on the industrial production processes. The proposed model was tested and applied in a real integrated steel mill, which also provided the reference results for related researches. At last, some concepts, computational issues and limi- tations of the proposed model were discussed.

Interlinking climate change with waterenergy-food nexus and related ecosystem processes in California case studies

Global climate change creates critical challenges with increasing temperature,reducing snowpack,and changing precipitation for water,energy,and food,as well as ecosystem processes at regional scales.Ecosystem services provide life support,goods,and natural resources from water,energy,and food,as well as the environments.There are knowledge gaps from the lack of conceptual framework and practices to interlink major climate change drivers of water resources with water-energy-food nexus and related ecosystem processes.This paper provided an overview of research background,developed a conceptual framework to bridge these knowledge gaps,summarized California case studies for practices in cross sector ecosystem services,and identified future research needs.In this conceptual framework,climate change drivers of changing temperature,snowpack,and precipitation are interlinked with life cycles in water,energy,food,and related key elements in ecosystem processes.Case studies in California indicated climate change affected variation in increasing temperature and changing hydrology at the regional scales.A large variation in average energy intensity values was also estimated from ground water and federal,state,and local water supplies both within each hydrological region and among the ten hydrological regions in California.The increased regional temperature,changes in snowpack and precipitation,and increased water stresses from drought can reduce ecosystem services and affect the water and energy nexus and agricultural food production,as well as fish and wildlife habitats in the Sacramento-San Joaquin Delta(Delta)and Central Valley watersheds.Regional decisions and practices in integrated management of water,energy,food,and related ecosystem processes are essential to adapt and mitigate global climate change impacts at the regional scales.Science and policy support for interdisciplinary research are critical to develop the database and tools for comprehensive analysis to fill knowledge gaps and address ecosystem service complexity,the related natural resource investment,and integrated planning needs.