Advances of macroalgae biomass for the third generation of bioethanol production

In recent years, utilization of renewable sources for biofuel production is gaining popularity due to growing greenhouse gas (GHG) emissions which causes global warming. There has been a great effort in exploring alternative feedstock for bioethanol production. In this context, the production of third-generation bioethanol from macroalgae has emerged as an alternative feedstock to food crop-based starch and lignocellulosic biomass. This is mainly due to the fast growth rate of macroalgae, no competition with agricultural land, high carbohydrate content and relatively simple processing steps compared to lignocellulosic biomass. This review paper provides an insight of recent innovative approaches for macroalgae bioethanol production, including conventional and advanced hydrolysis process to produce fermentable sugar, various fermentation technologies, economic analysis and life cycle assessment. With the current technology maturity, efficient utilization of macroalgae as sustainable source for bioethanol and other value-added chemicals production could be achieved in the near future.     

Comparative Analysis of Synthetic Natural Gas versus Hydrogen Production from Bagasse

A rigorous and comparative evaluation of two biomass‐to‐gases (BtG) conversion routes was performed and, according to this outcome, it is suggested which of the options evaluated is most desirable. These options, the hydrogen and synthetic natural gas (SNG) production, were designed in Aspen Plus process simulation software. Sugar cane bagasse was considered as feedstock. Mass and energy balance data were extracted from the simulations, and consequently thermodynamic (exergy analysis), economic (financial and uncertainty analysis), and environmental (CO₂ emissions) evaluations were carried out. Exergy and environmental analysis favor the SNG production while the hydrogen route provides higher profits.     

2D representation of life cycle greenhouse gas emission and life cycle cost of energy conversion for various energy resources

We suggest a 2D-plot representation combined with life cycle greenhouse gas (GHG) emissions and life cycle cost for various energy conversion technologies. In general, life cycle assessment (LCA) not only analyzes at the use phase of a specific technology, but also covers widely related processes of before and after its use. We use life cycle GHG emissions and life cycle cost (LCC) to compare the energy conversion process for eight resources such as coal, natural gas, nuclear power, hydro power, geothermal power, wind power, solar thermal power, and solar photovoltaic (PV) power based on the reported LCA and LCC data. Among the eight sources, solar PV and nuclear power exhibit the highest and the lowest LCCs, respectively. On the other hand, coal and wind power locate the highest and the lowest life cycle GHG emissions. In addition, we used the 2D plot to show the life cycle performance of GHG emissions and LCCs simultaneously and realized a correlation that life cycle GHG emission is largely inversely proportional to the corresponding LCCs. It means that an expensive energy source with high LCC tends to have low life cycle GHG emissions, or is environmental friendly. For future study, we will measure the technological maturity of the energy sources to determine the direction of the specific technology development based on the 2D plot of LCCs versus life cycle GHG emissions.     

CO2 utilization for methanol production; Optimal pathways with minimum GHG reduction cost

Mitigating CO₂ emissions from industries and other sectors of our economy is a critical component of building a sustainable economy. This paper investigates two different methanol synthesis routes based on CO₂ utilization (CO₂ capture and utilization [CCU], and tri-reforming of methane [TRM]), and compares the results with the conventional methanol production using natural gas as the feedstock (NG-MeOH). A comprehensive techno-economic analysis (TEA) model that includes the findings of the life cycle assessment (LCA) models of methanol production using various CO₂ utilization pathways is conducted. Economic analysis is conducted by developing a cost model that is connected to the simulation models for each production route. Compared to the conventional process (with a GHG emission of 0.6 kg CO₂/kg MeOH), the lifecycle GHG reduction of 1.75 and 0.41 kg CO₂/kg MeOH are achievable in the CCU and TRM pathways, respectively. Furthermore, the results indicate that, under current market conditions and hydrogen production costs, methanol production via CO₂ hydrogenation will result in a cost approximately three times higher than that of the conventional process. The integrated TEA–LCA model shows that this increased cost of production equates to a required life cycle GHG reduction credit of $279 to $422 per tonne of CO₂ utilized, depending on construction material and selected pathway. Additionally, when compared to the CO₂ hydrogenation route, the tri-reforming process (TRM-MeOH) can result in a 42% cost savings. Furthermore, a minimum financial support of $56 per tonne utilized CO₂ will be required to make the TRM-MeOH process economically viable.     

天然气分散制氢的技术经济分析(英文)

It is well established that hydrogen has the potential to make a significant contribution to the world energy production.In U.S.,majority of hydrogen production plants implement steam methane reforming(SMR) for centralized hydrogen production.However,there is a wide lack of agreement on the nascent stage of using hydrogen as fuel in vehicles industry because of the difficulty in delivery and storage.By performing technological and economic analysis,this work aims to establish the most feasible hydrogen production pathway for automotives in near future.From the evaluation,processes such as thermal cracking of ammonia and centralized hydrogen production followed by bulk delivery are eliminated while on-site steam reforming of methanol and natural gas are the most technologically feasible options.These two processes are further evaluated by comprehensive economic analysis.The results showed that the steam reforming(SR) of natural gas has a shorter payback time and a higher return on investment(ROI) and internal rate of return(IRR).Sensitivity analysis has also been constructed to evaluate the impact of variables like NG feedstock price,capital of investment and operating capacity factor on the overall production cost of hydrogen.Based on this study,natural gas is prompted to be the most economically and technologically available raw material for short-term hydrogen production before the transition to renewable energy source such as solar energy,biomass and wind power.     

Life cycle assessment of HFC-134a production by calcium carbide acetylene route in China

HFC-134a is a widely used environment-friendly refrigerant. At present, China is the largest producer of HFC-134a in the world. The production of HFC-134a in China mainly adopts the calcium carbide acetylene route. However, the production route has high resource and energy consumption and large waste emission, and few of the studies addressed on the environmental performance of its production process. This study quantified the environmental performance of HFC-134a production by calcium carbide route via carrying out a life cycle assessment (LCA) using the CML 2001 method. And uncertainty analysis by Monte-Carlo simulation was also carried out. The results showed that electricity had the most impact on the environment, followed by steam, hydrogen fluoride and chlorine, and the impact of direct CO₂ emissions in calcium carbide production stage on the global warming effect also could not be ignored. Therefore, the clean energy (e.g., wind, solar, biomass, and natural gas) was used to replace coal-based electricity and coal-fired steam in this study, showing considerable environmental benefits. At the same time, the use of advanced production technologies could also improve environmental benefits, and the environmental impact of the global warming category could be reduced by 4.1% via using CO₂ capture and purification technology. The Chinese database of HFC-134a production established in this study provides convenience for the relevant study of scholars. For the production of HFC-134a, this study helps to better identify the specific environmental hotspots and proposes useful ways to improve the environmental benefits.     

CO2 Reduction to Substitute Natural Gas: Toward a Global Low Carbon Energy System

Methane has proven to be an outstanding energy carrier and is the main component of natural gas and substitute natural gas (SNG). SNG may be synthesized from the CO₂ and hydrogen available from various sources and may be introduced into the existing infrastructure used by the natural gas sector for transport and distribution to power plants, industry, and households. Renewable SNG may be generated when H₂ is produced from renewable energy sources, such as solar, wind, and hydro. In parallel, the use of CO₂-containing feed streams from fossil origin or preferably, from biomass, permits the avoidance of CO₂ emissions. In particular, the biomass-to-SNG conversion, combined with the use of renewable H₂ obtained by electrolysis, appears a promising way to reduce CO₂ emissions considerably, while avoiding energy intensive CO₂ separation from the bio feed streams. The existing technologies for the production of SNG are described in this short review, along with the need for renewed research and development efforts to improve the energy efficiency of the renewables-to-SNG conversion chain. Innovative technologies aiming at a more efficient management of the heat delivered in the exothermic methanation process are therefore highly desirable. The production of renewable SNG through the Sabatier process is a key process to the transition towards a global sustainable energy system, and is complementary to other renewable energy carriers such as methanol, dimethyl ether, formic acid, and Fischer-Tropsch fuels.     

浅谈合成氨装置过程控制技术发展趋势

介绍国内以天然气为原料合成氨装置过程控制的现状 ;找出与国外控制水平的差距 ,分析其原因 ,并浅述合成氨装置过程控制技术发展趋势。     

加快生物质废弃物吸附增强制可再生氢气

作为全球性的优质能源载体,氢的主要生产方式包括碳氢化合物（例如天然气、煤炭和生物质）的热化学过程以及使用电力来源与可再生能源（如风能或太阳能等）的水电解过程。目前的水电解技术在大规模制氢方面经济竞争力亟待提升。本文指出：为了在2060年实现碳中和,迫切需要开发绿氢制备新技术,大力发展可再生制氢和低碳制氢。具有碳捕集、利用和封存的碳氢化合物低碳制氢（蓝色）技术将占重要地位,随后逐步转向可再生制氢（绿色）,并有望全面实现零碳制氢,进而对长期低碳化社会的发展至关重要。文章提出我国生物质资源非常丰富,但生物质废弃物制氢的技术成熟度仍然较低,迫切需要开发从生物质中高效生产可再生氢气的新技术,以显著提高氢气产量并降低成本;吸附增强反应代表了一种可用于可持续生产氢的有前景的新技术;氢气的产率和纯度可以通过过程强化得到显著提高,制氢过程的强化可以在多功能反应器中实现,其中重整和/或气化、水煤气变换和CO₂移除步骤可将重整/水煤气变换反应催化剂和CO₂捕集剂混合而集成到一个反应器中。最后指出：由于该过程潜力巨大,因此应助推耦合气化和吸附增强反应过程从生物质废弃物中生产可再生氢气的工艺过程,以加快推进碳中和进程。     

循环流化床锅炉干馏煤气生产合成氨的技术经济探讨

分析了以循环流化床锅炉副产的干馏煤气生产合成氨的技术经济可行性。在锅炉所用的烟煤或褐煤价格较低而工厂现有的原料价格较高的条件下,以循环流化床锅炉所副产的干馏煤气代替现有的高价原料生产合成氨是可行的,该原料路线在小氮肥原料路线的改造方面有一定的应用前景。     

Reduction of greenhouse gas emissions via flexible operation of cross-sector integrated energy systems under uncertainties in demand,fuel prices,and solar irradiation

This work investigates how the flexible operation of the light industrial plants integrated in a cross-sector energy cluster with community energy systems can achieve further greenhouse gas (GHG) reductions under uncertainties associated with natural gas prices, solar irradiation, as well as heating, cooling, and electricity demand. The optimal flexible operation and design of a cross-sector integrated cluster comprising a bakery plant, a brewery, a confectionery plant, a residential building, and a supermarket under uncertainties are compared to the operation and design of systems without uncertainties. When uncertainties are considered, the overall GHG emissions of the integrated system with steady industrial production rates for all uncertainty scenarios are over 4% higher than the integrated system in the deterministic scenario (a single scenario). Flexible operation of the industrial plants, whereby production rates are varied throughout the day, contributes an additional 3% reduction in GHG emissions under uncertainties, where the GHG emissions are only 1% higher than the deterministic scenario. Additionally, the system with flexible production rates purchases over 14.3% less electricity from the grid and uses over 72.2% less natural gas for operating the backup boiler, which relies less on supplementary energy resources. This shows that optimally designed integrated systems with flexible industry production schedules are resilient to uncertainties in energy demands, daily weather fluctuations, and fuel prices.     

木质纤维素类生物质制取燃料及化学品的研究进展

木质纤维素类生物质含有丰富的纤维素和半纤维素多糖,通过微生物发酵将它们转化为能源及高附加值的化学品,对于缓解全球能源危机带来的压力和解决环境污染问题具有重要意义。介绍了木质纤维素类生物质的结构特征;评述了预处理方法,包括稀酸、高温液态水蒸气爆破、CO2爆破、氨爆、碱法、有机溶剂法、生物处理法;重点介绍由生物质生产乙醇、丁醇及生物柴油的研究现状。指出开发高效环保的预处理方法、构建耐毒高产菌株和应用连续发酵或补料批式发酵方式等是加快木质纤维素类生物质发酵利用工业化进程的关键所在。     

炼厂制氢技术路线选择和成本分析

初步讨论炼厂制氢的必要性,对规模化的制氢技术进行了简要介绍。通过有代表性的天然气、渣油、水煤浆、干粉煤为制氢原料,分析讨论各原料制氢流程的最佳技术路线配置和典型物料平衡,并对4类原料选定的技术路线制氢成本进行技术经济分析,从成本角度初步探讨适宜炼厂制氢的原料和技术路线选择,结果表明,煤作为原料制氢不仅在技术上具有可行性,在经济性上也表现出越来越强的优势,以煤为原料的制氢装置在炼厂特别是重质油炼厂中将会得到广泛应用。     

Integration of wind,solar and biomass over a year for the constant production of CH4 from CO2 and water

In this paper we optimize the combination of biomass, wind and solar energy for the constant production of synthetic methane. Biomass is used for the production of power and/or hydrogen. Photovoltaic solar and wind energy are used to obtain power. Water is electrolyzed generating oxygen and hydrogen, which is used to synthesize methane with CO₂. The model is formulated as an MINLP. The optimization suggests the production of power using solar energy complemented with biomass. Biomass is processed using indirect gasification and steam reforming. The hydrogen is produced from water electrolysis. The investment and production costs are 175 M€ and 0.38 €/Nm³ respectively. A sensitivity analysis shows that biomass is preferred for prices and investment below 50 €/t and 1500 €/kW. Solar energy is used for high cost of biomass if solar incidence is above 1200 kWh/m² yr. Wind use is restricted to low solar incidence and wind velocities above 9 m/s.     

Implications of biodiesel production and utilisation on global climate – A literature review

Over the last few years, the favourable political environment has led to an increasing use of biofuels in the worldwide transportation sector. This development is mainly driven by concerns about the security of energy supplies and the intention to mitigate anthropogenic greenhouse gases (GHG). However, recently, the sustainability of a broad biofuel production and use has, in particular, been strongly questioned. Against this background, in this study a literature review on available and recently published life cycle assessment (LCA) studies for biodiesel has been carried out and the potential GHG emission savings from biodiesel production and use compared to fossil diesel have been analysed. The results of the reviewed studies underline the significant influence of the effects of land use change and the importance of avoiding the conversion of natural land into agricultural areas. If no land use change takes place, the results show moderate to good GHG savings for biodiesel (depending on the type of converted raw materials as well as on the chosen biomass conversion technology). In particular, the biodiesel feedstock production and the source of energy for the production process strongly influence the overall result of the GHG balance of biodiesel.     

天然气裂解制乙炔尾气用于生产合成氨工艺改进

青海盐湖工业集团股份有限公司2套利用天然气裂解制乙炔尾气生产合成氨的装置,同样的原料成分,设计建设时间不同。在总结一期工程经验的基础上,对二期工艺流程作了较大的调整。改进后的合成氨工艺流程从设备投资、操作管理、运行成本、节能降耗等方面效果明显。     

Substratspezifische Stoff-Führung bei anaeroben Verfahren zur Methan-Gewinnung

Principles of material flow in anaerobic methane production processes . Rising prices of fossil energy are upgrading the importance of processes for generating fuels from organic wastes and from renewable biomass. Anaerobic digestion is a suitable approach for the production of fuel gas rich in methane from wet or liquid organic feedstock. Depending upon the biochemical characteristics of the digestion process and upon the physical conditions for an optimal mass transport, specific technical solutions have been found for treating typical substrates differing in chemical composition, digestability, and fluid mechanical behaviour; such substrates are waste water, sludges, and organic solids with a high liquid content. A survey is given on the principal systems now used for conducting material to be digested through the whole process and in particular through the bioreactor.     

后石油时代的来临及化工领域的应对思考

21世纪世界能源结构将发生巨大变化。世界许多国家在充分研究全球油气资源和社会经济发展趋势的基础上,已开始研究如何应对"后石油时代"人类生存的全球性问题,并由政府牵头制定相应的对策和计划,其中包括:开发利用氢能、生物燃料、太阳能和风能等可再生能源。从化工领域的角度提出建议:加快发展煤变油技术、加快发展天然气制油技术以及煤化工技术。     

Superstructure optimization of integrated fast pyrolysis‐gasification for production of liquid fuels and propylene

Motivated by the apparent advantages of fast pyrolysis and gasification, a novel integrated biorefinery plant is systematically synthesized for coproducing premium quality liquid fuels and propylene. The required heat and fluidization promotion of the fast pyrolyzer are provided by hot syngas from the gasifier. Light gas and syngas from the fast pyrolyzer are finally converted to hydrocarbons via Fischer‐Tropsch synthesis. Multiple syngas production technologies, hydrocarbon production and downstream upgrading routes are incorporated within a superstructure optimization based process synthesis framework. This is the first article to investigate the benefits associated with the introduction of conventional catalytic cracking and dewaxing from a systems engineering perspective. Surrogate models describing the gasifiers and rigorous equations for Fischer‐Tropsch effluents validated by our experimental collaborator are introduced. Through investigation of five scenarios the primary parameters affecting overall economic performance are identified through ranking of the relevant candidates. Comparisons of the hybrid conversion route and stand‐alone routes are made. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3155–3176, 2016     

A novel hybrid feedstock to liquids and electricity process: Process modeling and exergoeconomic life cycle optimization

This article proposes a novel hybrid low‐rank coal (LRC)/biomass/natural gas process for producing liquid fuels and electricity. The hybrid process highlights coexistence of indirect and direct liquefaction technologies, cogasification of char and biomass, and corefinery of LRC syncrude and Fischer–Tropsch syncrude. A process simulation based on detailed chemical kinetics is present to illustrate its feasibility. In addition, we propose an exergoeconomic life cycle optimization framework that seeks to maximize the primary exergy saving ratio, primary total overnight cost saving ratio, life cycle waste emissions avoidance ratio, and primary levelized cost saving ratio by comparing the proposed hybrid process to its reference stand‐alone subsystems. From the results, we can determine four optimal designs which yield competitive breakeven oil prices ranging from $1.87/GGE to $2.13/GGE. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3739–3753, 2014