Steam consumption prediction of a gas sweetening process with methyldiethanolamine solvent using machine learning approaches

This study proposes a comprehensive data processing and modeling framework for building high‐accuracy machine learning model to predict the steam consumption of a gas sweetening process. The data pipeline processes raw historical data of this application and identifies the minimum number of modeling variables required for this prediction in order to ease the applicability and practicality of such methods in the industrial units. On the modeling end, an empirical comparison of most of the state‐of‐the‐arts regression algorithms was run in order to find the best fit to this specific case study. The ultimate goal is to leverage this model to identify the achievable energy conservation opportunity in such plants. The historical data for this modeling was collected from a gas treating plant at South Pars Gas Complex for 3 years from 2017 to 2019. This data gets passed through a multistage data processing scheme that conducts multicollinearity analysis and model‐based feature selection. For model selection, a wide range of regression algorithms from different classes of regressor have been considered. Among all these methods, the Gradient Boosting Machines model outperformed the others and achieved the lowest cross‐validation error. The results show that this model can predict the steam consumption values with 98% R‐squared accuracy on the holdout test set. Furthermore, the offline analysis demonstrates that there is a potential of 2% energy saving, equivalent to 24 000 metric tons of annual steam consumption reduction, which can be achieved by mapping the underperforming energy consumption states of the unit to the expected performances predicted by the model.     

A cryogen‐based peak‐shaving technology: systematic approach and techno‐economic analysis

A peak‐shaving technology is recently proposed, which integrates peak‐electricity generation, cryogenic energy storage and CO₂ capture. In such a technology, off‐peak electricity is used to produce liquid nitrogen and oxygen in an air separation and liquefaction unit. At peak hours, natural gas (or alternative gases, e.g. from gasification of coal) is burned by oxygen from the air separation unit (oxy‐fuel combustion) to generate electricity. CO₂ produced is captured in the form of dry ice. Liquid nitrogen produced in the air separation plant not only serves as an energy storage medium but also supplies the low‐grade cold energy for CO₂ separation. In addition, waste heat from the tail gas can be used to superheat nitrogen in the expansion process to further increase the system efficiency. This article reports a systematic approach, with an aim to provide technical information for the system design. Three potential blending gases (helium, oxygen and CO₂) are considered not only for assessing thermodynamic performance but also for techno‐economic analysis. The peak‐shaving systems are also compared with natural gas combined cycle and an oxy–natural gas combined cycle in terms of capital cost and peak electricity production cost. Copyright © 2011 John Wiley & Sons, Ltd.     

3000kt／a柴油加氢装置节能优化分析

介绍了中国石化上海高桥分公司新建3000kt／a柴油加氢装置的工艺及生产概况．分析了目前装置节能措施现状。对其中存在不足的方面提出了改进设想。立足于装置生产实际,从优化操作参数和能量综合利用着手,分别介绍了节汽、节电、节约燃料气和节水等方面的优化方案。通过实施节能优化方案,与设计值相比,装置标定综合能耗降低了2．52kg标油／t。     

大连石化制氢装置加工天然气原料技术分析

加速天然气的生产和消费,发展天然气化工,减轻对石油的需求压力,确保国家能源安全,已成为加速我国化学工业结构调整、强化节能减排的必然趋势。大连石化拥有两套完全独立的制氢装置,单套装置的公称产氢能力为10×104m3/h(标准),每一套装置都包括造气单元和PSA提纯单元。该装置加工的原料为轻石脑油或液化石油气,成本昂贵,操作费用大。提出利用低价、节能的天然气作为装置替代原料的设想。可行性分析认为,天然气基本不含烯烃,且芳烃和环烷烃含量低,氢气产率高,可以避免催化剂积炭,延长催化剂寿命,是制氢的首选原料;加之天然气富含甲烷,其H/C较高,一般在3.8左右,单位产氢量的原料消耗较少。大连石化制氢装置改为加工天然气后,原料精制单元,包括加氢反应器和脱硫反应器、中温变换单元和PSA氢气提纯单元的操作参数均不发生改变,可以大大降低装置的原料消耗和燃料消耗,同时提高了蒸汽的产出量,减少了CO2的排放。     

Influence of blast‐furnace process thermal parameters on energy and exergy characteristics and exergy losses

The technology ‘blast furnace—converter’ dominates at present in the production of steel all over the world. Therefore, the blast‐furnace process is continuously being improved, among others, by raising the thermal parameters, such as temperature and oxygen‐enrichment of the blast, as well as the addition of auxiliary fuels. The changes in the consumption of coke go together with changes in the consumption of blast, the production of top‐gas and its consumption in Cowper stoves, as well as the production of electricity in the recovery turbogenerator utilizing the waste exergy of the top‐gas due to raised pressure. Related to a unit of pig iron production, these values are called energy (exergy) characteristics of the blast‐furnace plant. They serve as a quantity measure of the thermal improvement of the blast‐furnace process. This paper presents an algorithm of the process exergy analysis of simulative investigations of the influence of increased thermal parameters on the thermodynamic perfection of the process and the blast‐furnace plant. This algorithm bases on the theoretical empirical balance method of the ‘input–output’ type. By means of this algorithm the influence of increased thermal parameters of the process not only on the saving of coke but also of the blast can be determined, as well as of the production and composition of top‐gas, the consumption of top‐gas in the Cowper stoves and the production of electric energy in the recovery turbine. The blast‐furnace process displays a high exergy efficiency, whereas the process of compressing and preheating the blast is characterized by rather high exergy losses due to the application of the combustion process. It has been shown that the internal exergy losses in the blast furnace are comparable with the exergy losses in the processes of compressing and preheating of the blast. Calculations were carried out for a modern Polish blast furnace with a volume of 3200 m³. Copyright © 2005 John Wiley & Sons, Ltd.     

Liquefied natural gas submerged combustion vaporization facilities: process integration with power conversion units

Liquefied natural gas (LNG) vaporization facilities offer an excellent opportunity of primary energy saving by means of integration with power conversion units that is still weakly exploited in actual installations. This work focuses on the evaluation of primary energy saving achievable by the integration of an LNG vaporization facility with a gas turbine and with a cogenerative combined gas‐steam power plant. The fuel energy saving ratio is used as the main performance parameter to evaluate the primary energy saving derived by system integration, with respect to conventional submerged combustion vaporization. Twelve possible configurations are analyzed with steady‐state calculations. Results show that a primary energy saving greater than 15% with peak values up to 27%, corresponding to 2.98 TJ/year, is achievable. The paper shows that the fuel energy saving ratio can be used as a synthetic and effective parameter to estimate the energy‐saving potential of different plant configurations. Copyright © 2011 John Wiley & Sons, Ltd.     

扬子石化延迟焦化装置节能措施及实施效果

扬子石化0.8Mt/a延迟焦化装置由于建成较早,加工工艺落后,2011年综合能耗达到23.04kg标油/t。结合装置特点,实施燃料气、蒸汽及用水节能措施。燃料气降耗方面,对达到使用年限的加热炉空气预热器热管进行部分更换,加热炉效率由90%提高至92%;使用气体脱硫装置的富余0.5MPa蒸汽作为热源,对燃料气进行加热,减少燃料气实际耗量5.16%。蒸汽节能方面,利用富余0.5MPa蒸汽替代1.0MPa蒸汽,节省1.0MPa蒸汽用量5.11t/h;随着装置凝结水回收项目的竣工,计划改用凝结水替代部分大吹汽蒸汽;同时,现场消除蒸汽漏点,更换腐蚀、减薄的碳钢管线,将其材质升级为不锈钢。节水方面,使用硫回收净化污水替代工业水,节省工业水用量7000t/a;拟将装置各点排放的凝结水集中回收,补入装置除氧罐或放水罐,进一步节省工业水用量。上述措施的实施,使装置能耗由2012年的22.93kg标油/t降至2013年的21.25kg标油/t,降幅达7.3%。     

An efficient technique‐based distributed energy management for hybrid MG system: A hybrid QOCSOS‐RF technique

This paper proposes an efficient hybrid approach–based energy management strategy (EMS) for grid‐connected microgrid (MG) system. The primary objective of the proposed technique is to reduce the operational electricity cost and enhanced power flow between the source side and load side subject to power flow constraints. The proposed control scheme is a consolidated execution of both the random forest (RF) and quasi‐oppositional‐chaotic symbiotic organisms search algorithm (QOCSOS), and it is named as QOCSOS‐RF. Here, the QOCSOS can have the capacity to enhance the underlying irregular arrangements and joining to a superior point in the pursuit space. Likewise, the QOCSOS has prevalence in nonlinear frameworks due over the way that can insert and extrapolate the arbitrary information with high exactness. Here, the required load demand of the grid‐connected MG system is continuously tracked by the RF technique. The QOCSOS optimized the perfect combination of the MG with the consideration of the predicted load demand. Furthermore, in order to reduce the influence of renewable energy forecasting errors, a two‐strategy for energy management of the MG is employed. At that point, proposed model is executed in MATLAB/Simulink working platform, and the execution is assessed with the existing techniques.     

青岛炼化酸性水汽提装置流程模拟与优化

青岛炼化230t/h酸性水汽提装置是环保装置,目前正面临着兼顾环保与节能这一矛盾的难题。装置的环保功能,就是生产出合格的酸性气和净化水产品,保证使硫和氨氮对大气、水体的破坏最小;装置的节能功能,就是使作为汽提塔底热源的主要能耗——低低压蒸汽的消耗量最小。为实现这一目标,使用Aspen Plus流程模拟系统,建立青岛炼化酸性水汽提装置模型,并对模型进行验证和计算。通过模型,对装置各系统关键参数进行灵敏度分析。在此基础上,提出针对装置日常生产数据的优化方案。实施流程模拟优化后,在保证汽提塔顶含氨酸性气和塔底净化水产品质量条件下,通过有效组合、调控控制参数(中段回流量、汽提塔顶压力、中段回流温度),能使汽提塔的蒸汽能耗降低15%以上,有效解决了生产瓶颈,实现装置全年创效300万元以上。     

Designing environmentally sustainable electronic cooling systems using exergo‐thermo‐volumes

Thermo‐volumes allow the design engineer to expediently understand the thermal resistance of a given cooling solution (an indicator of performance) along with its flow resistance (an indicator of the pumping power, or energy consumption, which will be required by the fluid handler). In the present work, we expand upon thermo‐volumes by including the lifetime exergy cost (in units of Joules of availability destroyed) as a means to enable the consideration of resource consumption (and thus the environmental sustainability) of the cooling solution. To achieve these exergo‐thermo‐volumes, we reinterpret previous definitions of thermo‐volumes in terms of the entropy generated during heat transfer and fluid flow. The Guoy–Stodola theorem is used to convert this entropy generation into an ‘operational’ exergy loss. Next, based on the material choice and assembly processes used in creating the product, an embedded exergy consumption that accounts for the amount of exergy destroyed during extraction, transportation and disposal of the material is attached to the operational exergy loss. Thus, the total ‘cradle‐to‐cradle’ exergy loss of the solution is devised. In this framework, the optimal solution will be that which destroys the minimal amount of exergy. Correspondingly, instead of relying upon the coefficient of performance (which is focused on operational consumption), we propose evaluation of cooling solutions in terms of the heat removal capacity per unit lifetime exergy consumption. The paper concludes by illustrating applicability of the method to the design of an enterprise server. It should be noted that although the paper is focused on electronics cooling solutions, the methodology is designed to be sufficiently general for use in any thermal management application. Copyright © 2009 John Wiley & Sons, Ltd.     

A new modeling and solution method for optimal energy flow in electricity‐gas integrated energy system

With the increasing interdependency of electricity and gas, it is necessary to simultaneously investigate electric power system and natural gas system from the perspective of an electricity‐gas integrated energy system (EGIES). As an extension and integration of both optimal power flow (OPF) and optimal gas flow (OGF), optimal energy flow (OEF) is regarded as the cornerstone of the EGIES and lays an essential foundation for further research on the EGIES's operation and analysis considering stochastic conditions and contingency states. The objective of this paper is to develop a generalized mathematical model and a universally applicable simulation tool for the OEF problem. First, natural gas system is modeled in a way similar to electric power system according to electricity‐gas analogy analysis, where gas admittance, gas nodal admittance matrix, and the nodal equation of gas flow conservation are derived. Then, a generalized accurate OEF model is formulated by simultaneously integrating the OPF model and the OGF model as well as their coupling constraints in a unified modeling framework. Furthermore, an available hybrid optimization approach consisting of whale optimization algorithm, MATPOWER, hydraulic calculation iterative program, and nonstationary penalty function method is put forward to solve the OEF problem. The accuracy, feasibility, and applicability of the proposed modeling and solution method is finally demonstrated by analyzing Belgian 20‐node gas system combined with IEEE 30‐bus test system.     

基于六西格玛管理方法提高燃油锅炉汽油比

以浙江中烟工业有限责任公司杭州卷烟厂成功提高燃油锅炉汽油比的实践为例,介绍能源管理项目团队利用六西格玛管理方法,研究企业提高燃油锅炉汽油比的途径,通过对能耗数据进行统计分析,发现隐藏于表象之下的不合理耗能环节,优化设备运行参数,从而实现节能减排降耗.     

Energy efficiency at the paper mill—dilemma of improvement

The paper industry is heavily using energy during all the phases of the manufacturing process. This is especially the case in Nordic mills where pressure ground wood is the source of fiber. The purpose of this case study is to show how energy consumption behaves on a monthly basis in a Finnish paper mill that has several paper machine lines. The research examines different categories of energy usage, as well as the overall costs. The results show that the monthly energy usage varies significantly. The electricity consumption of the case mill is rather steady, but there is significant monthly variation in steam and natural gas consumption. Moreover, steam and electricity unit costs increased significantly when coming to the end of the research period. The longitudinal case data shows that it is difficult to enhance energy consumption per produced unit at the paper mill. One reason for this is the bleak demand outlook for the end products, which often result in downsizing and closing operations inside the integrated unit.     

Natural gas‐based transportation in the USA: economic evaluation and policy implications based on MARKAL modeling

The recent divergence in domestic energy costs between oil and natural gas drives an investigation of the potential for further demand‐side utilization of natural gas in the USA. An economic assessment of the US transportation sector was conducted with a focus on the penetration of technologies that use natural gas as a fuel. Bottom‐up modeling of the US energy system using the market allocation framework enabled estimation of the optimal technology mix in both the light‐duty and heavy‐duty vehicle segments, over a 40‐year time horizon, under various scenarios of technical learning rates and natural gas prices. A modified functional form of Moore's law was developed and anchored to municipal transit bus data, to represent technical learning with regard to natural gas vehicle costs. Modeling results suggest that the present levels of natural gas vehicle penetration are suboptimal and a number of market failures were identified, which are most likely to propagate under‐adoption into the foreseeable future. Some policy guidelines, aimed at the federal level, were outlined as potential responses to the market failures discussed herein. Copyright © 2014 John Wiley & Sons, Ltd.     

A review on biomass‐based hydrogen production and potential applications

In this paper, a detailed review is presented to discuss biomass‐based hydrogen production systems and their applications. Some optimum hydrogen production and operating conditions are studied through a comprehensive sensitivity analysis on the hydrogen yield from steam biomass gasification. In addition, a hybrid system, which combines a biomass‐based hydrogen production system and a solid oxide fuel cell unit is considered for performance assessment. A comparative thermodynamic study also is undertaken to investigate various operational aspects through energy and exergy efficiencies. The results of this study show that there are various key parameters affecting the hydrogen production process and system performance. They also indicate that it is possible to increase the hydrogen yield from 70 to 107 g H₂ per kg of sawdust wood. By studying the energy and exergy efficiencies, the performance assessment shows the potential to produce hydrogen from steam biomass gasification. The study further reveals a strong potential of this system as it utilizes steam biomass gasification for hydrogen production. To evaluate the system performance, the efficiencies are calculated at particular pressures, temperatures, current densities, and fuel utilization factors. It is found that there is a strong potential in the gasification temperature range 1023–1423 K to increase energy efficiency with a hydrogen yield from 45 to 55% and the exergy efficiency with hydrogen yield from 22 to 32%, respectively, whereas the exergy efficiency of electricity production decreases from 56 to 49.4%. Hydrogen production by steam sawdust gasification appears to be an ultimate option for hydrogen production based on the parametric studies and performance assessments that were carried out through energy and exergy efficiencies. Finally, the system integration is an attractive option for better performance. Copyright © 2012 John Wiley & Sons, Ltd.     

Modelling and testing of a hybrid solar‐biomass ORC‐based micro‐CHP system

Expanders employed recently in organic Rankine cycle (ORC)‐based systems suffer from key problems including excessive working fluid leakage, thermal losses, low isentropic efficiency and high cost. The majority of the units available in the market are for medium and large‐scale applications (>100 kW) with no commercial micro‐scale expanders available and applicable for ORC units for residential and building applications. Moreover, the majority of the studies conducted on ORC expanders employed HFC and HCFC working fluids which have high global warming potential leading to negative environmental impacts. In this study, a micro‐scale CHP system based on the ORC technology is theoretically and experimentally investigated to provide the thermal needs and part of the electrical demands for residential applications. An innovative design for a hybrid ORC‐based micro‐CHP system is proposed using a biomass boiler and a solar concentrator to run the CHP system providing more reliable and clean operation compared to conventional natural gas‐driven units. The micro‐CHP system employs a new type small‐scale scroll expander with a compact design, integrating the generator and the turbine in a single unit. A numerical model was developed using the Engineering Equation Solver (EES) software to simulate the thermodynamic behaviour of the ORC unit predicting the thermal and electrical performance of the overall CHP system. In addition, an experimental setup was built to test the whole ORC–CHP system performance under different conditions, and the effect of various operational parameters on the system performance has been presented using an environmentally friendly HFE7100 working fluid. The maximum electric power generated by the expander was in the range of 500 W at a pressure differential of about 4.5 bars. The attained expander isentropic efficiency was over 80% at its peak operating conditions with no fluid leakage observed. Being mass‐produced with low cost in the automotive industry along with the high isentropic efficiency and the leakage‐free performance, the proposed compact scroll expander represents a potential candidate to be used in the development of micro‐scale ORC–CHP units for building applications. Copyright © 2013 John Wiley & Sons, Ltd.     

荆门石化气体分馏装置流程模拟技术应用

荆门石化总厂气体分馏装置处理能力为55×104t/a,采用脱丙烷塔、脱乙烷塔、丙烯塔(两塔)三塔流程。以该气体分馏装置为研究对象,采用Aspen Plus流程模拟软件,建立与装置实际工况相符合的稳态流程模拟模型。利用此模型,对脱丙烷塔、脱乙烷塔、丙烯塔等进行灵敏度分析,研究各塔压力、热负荷、回流比等参数间的相互关系,并以模型为指导,对装置进行如下优化调整:脱丙烷塔顶控制压力由1.85MPa下调到1.40MPa,既能满足产品质量要求,又能大幅降低装置蒸汽消耗,塔顶温度和塔底温度均大幅下降,塔底温度由109℃降到95℃左右,蒸汽流量平均值下降约5t/h,使蒸汽单耗下降到约0.1kg标油/t,该装置综合能耗下降7.6kg标油/t。装置年开工时数按8400h计算,全年减少蒸汽消耗4.2×104t,蒸汽价格按150元/t计算,则全年共创节能效益630万元,装置能耗大幅降低。     

洛阳石化炼油装置节能潜力分析及优化措施

对洛阳石化炼油装置节能潜力进行了分析,并针对电、蒸汽和燃料气三项节能重点制定了优化措施。节约燃料气的措施为:优化常减压换热网络;连续重整扩能消缺改造,停运制氢装置;降低加热炉排烟温度,提高加热炉整体效率;更换高活性催化剂,降低加氢反应温度。节约电的措施为:对催化裂化装置烟机及再生器旋分器进行检修改造,提高烟机效率;负荷富裕的往复式压缩机增设无级气量调节系统;更换高能耗变压器,降低无功损耗;对部分能力过剩的机泵进行节能改造。节约蒸汽的措施为:气分装置取消蒸汽;焦化装置大吹汽改用凝结水;关闭蜡油加氢装置循环氢压缩机反飞动阀;整合乙醇胺溶剂系统;优化蒸汽管网运行,停用部分蒸汽线。措施实施后,洛阳石化每年可节约燃料13705t,节约用电21786MW·h,节约蒸汽150800t,综合能耗实现57.87kg标油/t原油的目标。     

溶剂再生装置的流程模拟与优化

天津石化1号溶剂再生装置,设计处理能力310t/h,主要处理来自两套焦化液化气脱硫塔、1号焦化干气脱硫塔、2号焦化干气脱硫塔以及气体分馏装置的富液和瓦斯脱硫塔的富液。以该装置为研究对象,应用流程模拟软件,建立稳态流程模拟模型。利用此模型,对影响装置能耗的参数进行灵敏度分析,研究塔压力、热负荷、进料位置、进料温度、回流比等参数间的相互关系,并以模型为指导,以节能和经济效益最大化为目标,对装置进行优化调整:将胺液浓度由32%提高至38%,再生塔回流比(质量比)由设计值1.91降低至1.0,塔顶压力由0.12MPa降低至0.10MPa,回流温度由44.7℃提高至50℃,既保证塔顶酸性气浓度达标,贫液硫含量也能满足脱硫系统需要。通过调整优化,使再生塔的蒸汽耗量明显降低,节约蒸汽6t/h,溶剂再生装置每月节电2.5×104kW.h,每年创造经济效益771万元。     

Energy‐saving evaluation of a thermosyphon heat recovery unit for an air‐conditioning system

The energy‐saving effect and economic benefits of a thermosyphon heat recovery unit installed in a shopping mall are investigated. To evaluate the thermal performance of the heat recovery unit in a season, a seasonal temperature effectiveness is advanced, and its calculation formula is deduced referring to the calculation method of seasonal energy efficiency ratio (SEER) for an air conditioner. The annual operating energy‐saving effect of the unit is analyzed by using the seasonal temperature effectiveness while the static economic evaluation method is applied for the economic benefits analysis of the unit. The analysis results indicate the seasonal temperature effectiveness of the unit is 66.08% in the winter and 55.43% in the summer. The energy‐saving effect of the unit is quite remarkable, and the payback time is about 2.65 years. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21049