Well-to-Wheels analysis of hydrogen production from bio-oil reforming for use in internal combustion engines

The environmental profile of hydrogen depends greatly on the nature of the feedstock and the production process. In this Well-to-Wheels (WTW) study, the environmental impacts of hydrogen production from lignocellulosic biomass via pyrolysis and subsequent steam reforming of bio-oil were evaluated and compared to the conventional production of hydrogen from natural gas steam reforming. Hydrogen was assumed to be used as transportation fuel in an internal combustion engine vehicle. Two scenarios for the provision of lignocellulosic biomass were considered: wood waste and dedicated willow cultivation. The WTW analysis showed that the production of bio-hydrogen consumes less fossil energy in the total lifecycle, mainly due to the renewable nature of the fuel that results in zero energy consumption in the combustion step. The total (fossil and renewable) energy demand is however higher compared to fossil hydrogen, due to the higher process energy demands and methanol used to stabilize bio-oil. Improvements could occur if these are sourced from renewable energy sources. The overall benefit of using a CO₂ neutral renewable feedstock for the production of hydrogen is unquestionable. In terms of global warming, production of hydrogen from biomass through pyrolysis and reforming results in major GHG emissions, ranging from 40% to 50%, depending on the biomass source. The use of cultivated biomass aggravates the GHG emissions balance, mainly due to the N₂O emissions at the cultivation step.     

Hydrogen-rich gas production from biomass air and oxygen/steam gasification in a downdraft gasifier

Biomass gasification is an important method to obtain renewable hydrogen. However, this technology still stagnates in a laboratory scale because of its high-energy consumption. In order to get maximum hydrogen yield and decrease energy consumption, this study applies a self-heated downdraft gasifier as the reactor and uses char as the catalyst to study the characteristics of hydrogen production from biomass gasification. Air and oxygen/steam are utilized as the gasifying agents. The experimental results indicate that compared to biomass air gasification, biomass oxygen/steam gasification improves hydrogen yield depending on the volume of downdraft gasifier, and also nearly doubles the heating value of fuel gas. The maximum lower heating value of fuel gas reaches 11.11 MJ/N m³ for biomass oxygen/steam gasification. Over the ranges of operating conditions examined, the maximum hydrogen yield reaches 45.16 g H₂/kg biomass. For biomass oxygen/steam gasification, the content of H₂ and CO reaches 63.27–72.56%, while the content of H₂ and CO gets to 52.19–63.31% for biomass air gasification. The ratio of H₂/CO for biomass oxygen/steam gasification reaches 0.70–0.90, which is lower than that of biomass air gasification, 1.06–1.27. The experimental and comparison results prove that biomass oxygen/steam gasification in a downdraft gasifier is an effective, relatively low energy consumption technology for hydrogen-rich gas production.     

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.     

Energy and exergy analysis and optimization of biomass gasification process for hydrogen production (based on air,steam and air/steam gasifying agents)

Growing the consumption of fossil fuels and emerging global warming issue have driven the research interests toward renewable and environmentally friendly energy sources. Biomass gasification is identified as an efficient technology to produce sustainable hydrogen. In this work, energy and exergy analysis coupled with thermodynamic equilibrium model were implemented in biomass gasification process for production of hydrogen. In this regard, a detailed comparison of the performance of a downdraft gasifier was implemented using air, steam, and air/steam as the gasifying agents for horse manure, pinewood and sawdust as the biomass materials. The comparison results indicate that the steam gasification of pinewood generates a more desired product gas compositions with a much higher hydrogen exergy efficiency and low exergy values of unreacted carbon and irreversibility. Then the effects of the inherent operating factors were investigated and optimized applying a response surface methodology to maximize hydrogen exergy efficiency of the process. A hydrogen exergy efficiency of 44% was obtained when the product gas exergy efficiency reaches to the highest value (88.26%) and destruction and unreacted carbon efficiencies exhibit minimum values of 7.96% and 1.9%.     

Catalytic steam reforming of tar for enhancing hydrogen production from biomass gasification: a review

Presently, the global search for alternative renewable energy sources is rising due to the depletion of fossil fuel and rising greenhouse gas (GHG) emissions. Among alternatives, hydrogen (H₂) produced from biomass gasification is considered a green energy sector, due to its environmentally friendly, sustainable, and renewable characteristics. However, tar formation along with syngas is a severe impediment to biomass conversion efficiency, which results in process-related problems. Typically, tar consists of various hydrocarbons (HCs), which are also sources for syngas. Hence, catalytic steam reforming is an effective technique to address tar formation and improve H₂ production from biomass gasification. Of the various classes in existence, supported metal catalysts are considered the most promising. This paper focuses on the current researching status, prospects, and challenges of steam reforming of gasified biomass tar. Besides, it includes recent developments in tar compositional analysis, supported metal catalysts, along with the reactions and process conditions for catalytic steam reforming. Moreover, it discusses alternatives such as dry and autothermal reforming of tar.     

Methanation of syngas from biomass gasification: An overview

Traditional fossil fuel overuse could lead to global warming and environmental pollution. As a renewable energy, biomass energy is a sustainable and low pollution carbon energy, which has a wide range of sources. Syngas production from biomass thermochemical conversion is a promising technology to realize effective utilization of the renewable energy. Syngas produced from gasification could be further converted into value-added chemicals via the method of Fischer-Tropsch synthesis. Syngas and CO₂ methanation could transform renewable energy into feasible transport and high-density energy. However, tar formation and catalyst deactivation are the main problem during the biomass gasification and methanation. This review sheds light on the development of biomass gasification and syngas methanation. Firstly, we presented the common reactors and some other factors during gasification. Secondly, we provide a comprehensive introduction of the advanced active catalyst for gasification and syngas methanation. Finally, some representative large-scale and commercial plants and companies for biomass gasification were compared and discussed in details. Then the prospective developments in combination of gasification and methanation were concluded to give an outlook for biomass gasification and its downstream development.     

Comparison of co–gasification efficiencies of coal,lignocellulosic biomass and biomass hydrolysate for high yield hydrogen production

The diversity in the chemical composition of lignocellulosic feedstocks can affect the conversion technologies employed for hydrogen production. Gasification and co–gasification activities of lignocellulosic biomass, biomass hydrolysate, and coal were evaluated for hydrogen rich gas production. The hydrolysates of biomass materials showed the best performance for gasification. The results indicated that biomass hydrolysates obtained from lignocellulosic biomass were more sensitive to degradation and therefore, produced more hydrogen and gaseous products than that of lignocellulosic biomass. The effects of feed (kenaf and sorghum hydrolysate), flow rate (0.3–2.0 mL/min) and temperature (700–900 °C) on hydrogen production and gasification yields were investigated. It was observed that 0.5 mL/min the optimum feed flow rate for the maximum total gas and hydrogen production. Synergism effects were observed for co–gasification of coal/biomass and coal/biomass hydrolysate. In all co–gasification processes, the main component of the gas mixture was hydrogen (≥70%).     

Political,economic and environmental impacts of biomass-based hydrogen

The purpose of this study is to assess the political, economic and environmental impacts of producing hydrogen from biomass. Hydrogen is a promising renewable fuel for transportation and domestic applications. Hydrogen is a secondary form of energy that has to be manufactured like electricity. The promise of hydrogen as an energy carrier that can provide pollution-free, carbon-free power and fuels for buildings, industry, and transport makes it a potentially critical player in our energy future. Currently, most hydrogen is derived from non-renewable resources by steam reforming in which fossil fuels, primarily natural gas, but could in principle be generated from renewable resources such as biomass by gasification. Hydrogen production from fossil fuels is not renewable and produces at least the same amount of CO₂ as the direct combustion of the fossil fuel. The production of hydrogen from biomass has several advantages compared to that of fossil fuels. The major problem in utilization of hydrogen gas as a fuel is its unavailability in nature and the need for inexpensive production methods. Hydrogen production using steam reforming methane is the most economical method among the current commercial processes. These processes use non-renewable energy sources to produce hydrogen and are not sustainable. It is believed that in the future biomass can become an important sustainable source of hydrogen. Several studies have shown that the cost of producing hydrogen from biomass is strongly dependent on the cost of the feedstock. Biomass, in particular, could be a low-cost option for some countries. Therefore, a cost-effective energy-production process could be achieved in which agricultural wastes and various other biomasses are recycled to produce hydrogen economically. Policy interest in moving towards a hydrogen-based economy is rising, largely because converting hydrogen into useable energy can be more efficient than fossil fuels and has the virtue of only producing water as the by-product of the process. Achieving large-scale changes to develop a sustained hydrogen economy requires a large amount of planning and cooperation at national and international alike levels.     

Review on fermentative biohydrogen production from water hyacinth,wheat straw and rice straw with focus on recent perspectives

Hydrogen (H₂) is often considered as the best option to store energy coming from renewable sources. Hydrogen production from lignocellulosic biomass via fermentation offers low cost and environmental friendly method in terms of energy balance and provides a sustainable pathway for utilization of huge amount of unused biomass. In this regard, special attention on potential of different lignocellulosic biomass is required. In this paper, the fermentative hydrogen production from three carbohydrates-rich biomass: water hyacinth, wheat straw and rice straw is comprehensively reviewed. In other point of view, usage of H₂ has a 10% growth annually that will reach to 8–10% of total energy in 2025. Furthermore, research on recent trends of fermentative hydrogen production is crucial and vital. However, the majority of the published researches in the last decade confirmed that some challenges exists which are the process optimization, effecting parameters and commercialization aspects.     

Assessment of sustainable high temperature hydrogen production technologies

Apart from being a major feedstock for chemical production, hydrogen is also a very promising energy carrier for the future energy. Currently hydrogen is predominantly produced via fossil routes, but as green energy sources are gaining a larger role in the energy mix, novel and green production routes are emerging. The most abundant renewable hydrogen sources are water and biomass, which allow several possible processing routes, such as electrolysis, thermochemical cycles and gasification. By introducing heat to the process the required electricity demand can be reduced (high temperature electrolysis) or practically eliminated (thermochemical cycles). Each renewable hydrogen production route has its own strength and weaknesses; the choice of the most suitable method is always dependent on the economical potentials and the location. The aim of this paper is to evaluate the different high temperature, renewable hydrogen production technologies.     

Novel hydrogen‐rich gas production by steam gasification of biomass in a research‐scale rotary tubular helical coil gasifier

The concept of biomass steam gasification offers platform for production (i) of hydrogen, (ii) hydrocarbons and (iii) value added chemicals. Majority of these developments are either in nascent or in pilot/demonstration stage. In this context, there exists potential for hydrogen production via biomass steam gasification. Gaseous products of biomass steam gasification consist of large percentage of CO, CH₄ and other hydrocarbons, which can be converted to hydrogen through water‐gas‐shift reaction, steam reforming and cracking respectively. Although there are many previous research works showing the potential of production of hydrogen from biomass in a two stage process, challenges remain in extended biomass and char gasification so as to reduce the amount of carbon in the residual char as well as improve conversion of heavy hydrocarbon condensates to hydrogen rich gas. In the current work, the characteristics of biomass steam gasification in an in‐house designed rotary tubular helical coil reactor at temperatures less than 850 °C, in the presence of superheated steam, were presented. The objectives were to obtain high carbon conversion in the primary biomass steam gasification step (upstream) and high product gas yield and hydrogen yield in the secondary fixed bed catalytic step (downstream). The influence of temperature, steam‐to‐biomass ratio and residence time on product gas yield in the rotary tubular helical coil gasifier was studied in detail using one of the abundantly available biomass sources in India‐rice husk. Further, enhancement of product gas yield and hydrogen yield in a fixed bed catalytic converter was studied and optimized. In the integrated pathway, a maximum gas yield of 1.92 Nm³/kg moisture‐free biomass was obtained at a carbon conversion efficiency of 92%. The maximum hydrogen purity achieved under steady state conditions was 53% by volume with a hydrogen yield of 91.5 g/kg of moisture‐free biomass. This study substantiates overall feasibility of production of high value hydrogen from locally available biomass by superheated steam gasification followed by catalytic conversion. Copyright © 2016 John Wiley & Sons, Ltd.     

Techno-economic assessment of hydrogen production processes for the hydrogen economy for the short and medium term

Hydrogen is expected to play a significant role in the future energy system. A key enabler to a hydrogen-including economy will be the development and deployment of processes that can produce hydrogen whilst satisfying the criteria for sustainability, i.e. economic competitiveness, environmental protection and security of energy supply. This paper evaluates selected hydrogen production processes based on natural gas steam reforming, coal and biomass gasification and water electrolysis. These options are expected to play a significant role in the short to medium term. Industrial large-scale processes, using natural gas and coal, will constitute the most important routes. However, increasing prices for natural gas are likely to make coal gasification more competitive. Biomass gasification could become important if present technological barriers are overcome. Electrolytic hydrogen, however, will likely be practical for niche applications in the short term due to the high electricity costs, especially when electricity is generated by renewable energy sources.     

A review of hydrogen production via biomass gasification and its prospect in Bangladesh

Hydrogen has been using as one of the green fuel along with conventional fossil fuels which has enormous prospect. A new dimension of hydrogen energy technology can reduce the dependency on non-renewable energy sources due to the rapid depletion of fossil fuels. Hydrogen production via Biomass (Municipal solid waste, Agricultural waste and forest residue) gasification is one of the promising and economic technologies. The study highlights the hydrogen production potential from biomass through gasification technology and review the parameters effect of hydrogen production such as temperature, pressure, biomass and agent ratio, equivalence ratios, bed material, gasifying agents and catalysts effect. The study also covers the all associated steps of hydrogen separation and purification, WGS reaction, cleaning and drying, membrane separation and pressure swing adsorption (PSA). To meet the huge and rising energy demand, many countries made a multidimensional power development plan by adding different renewable, nuclear and fossil fuel sources. A large amount of biomass (total biomass production in Bangladesh is 47.71 million ton coal equivalent where 37.16, 3.49 and 7.04 MTCE are agricultural, MSW and forest residue based biomass respectively by 2016) is produced from daily uses by a big number of populations in a country. It also includes total feature of biomass gasification plant in Bangladesh.     

Evaluation of hydrogen production methods using the Analytic Hierarchy Process

In this paper, seven common hydrogen production processes are evaluated using the Analytic Hierarchy Process (AHP) in respect to five criteria. The processes to be evaluated are steam methane reforming (SMR), partial oxidation of hydrocarbons (POX), coal gasification (CG), biomass gasification (BG), the combination of photovoltaics and electrolysis (PV–EL), the combination of wind power and electrolysis (W–EL) and the combination of hydropower and electrolysis (H–EL). The selected criteria that were used in the evaluation, for each of the seven hydrogen production processes are CO₂ emissions, operation and maintenance costs, capital cost, feedstock cost and hydrogen production cost. According to the evaluation, the processes that combine renewable energy sources with electrolysis (PV–EL, W–EL and H–EL) rank higher in classification than conventional processes (SMR, POX, CG and BG).     

Technoeconomic analysis of a methanol plant based on gasification of biomass and electrolysis of water

Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO₂ from post-combustion capture and autothermal reforming of natural gas or biogas. Underground gas storage of hydrogen and oxygen was used in connection with the electrolysis to enable the electrolyser to follow the variations in the power produced by renewables. Six plant configurations, each with a different syngas production method, were compared. The plants achieve methanol exergy efficiencies of 59–72%, the best from a configuration incorporating autothermal reforming of biogas and electrolysis of water for syngas production. The different processes in the plants are highly heat integrated, and the low-temperature waste heat is used for district heat production. This results in high total energy efficiencies (∼90%) for the plants. The specific methanol costs for the six plants are in the range 11.8–25.3 €/GJ_exergy. The lowest cost is obtained by a plant using electrolysis of water, gasification of biomass and autothermal reforming of natural gas for syngas production.     

Multi-objective,multi-period optimization of biomass conversion technologies using evolutionary algorithms and mixed integer linear programming (MILP)

The design and operation of energy systems are key issues for matching energy supply and demand. A systematic procedure, including process design and energy integration techniques for sizing and operation optimization of poly-generation technologies is presented in this paper. The integration of biomass resources as well as a simultaneous multi-objective and multi-period optimization, are the novelty of this work. Considering all these concepts in an optimization model makes it difficult to solve. The decomposition approach is used to deal with this complexity.Several options for integrating biomass in the energy system, namely back pressure steam turbines, biomass rankine cycles (BRC), biomass integrated gasification gas engines (BIGGE), biomass integrated gasification gas turbines, production of synthetic natural gas (SNG) and biomass integrated gasification combined cycles (BIGCC), are considered in this paper. The goal is to simultaneously minimize costs and CO₂ emission using multi-objective evolutionary algorithms (EMOO) and Mixed Integer Linear Programming (MILP).Finally the proposed model is demonstrated by means of a case study. The results show that the simultaneous production of electricity and heat with biomass and natural gas are reliable upon the established assumptions. Furthermore, higher primary energy savings and CO₂ emission reduction, 40%, are obtained through the gradual increase of renewable energy sources as opposed to natural gas usage. However, higher economic profitability, 52%, is achieved with natural gas-based technologies.     

Integrated adsorption steam gasification for enhanced hydrogen production from palm waste at bench scale plant

The generation of hydrogen-enriched synthesis gas from catalytic steam gasification of biomass with in-situ CO₂ capture utilizing CaO has a high perspective as clean energy fuels. The present study focused on the process modeling of catalytic steam gasification of biomass using palm empty fruit bunch (EFB) as biomass for hydrogen generation through experimental work. Experiment work has been carried out using a fluidized bed gasifier on a bench-scale plant. The established model integrates the kinetics of EFB catalytic steam gasification reactions, in-situ capturing of CO₂, mass and energy balance calculations. Chemical reaction constants have been calculated via the parameters fitting optimization approach. The influence of operating parameters, mainly temperature, steam to biomass, and sorbent to biomass ratio, was investigated for the hydrogen purity and yield through the experimental study and developed model. The results predicted approximately 75 vol% of the hydrogen purity in the product gas composition. The maximum H₂ yield produced from the gasifier was 127 gH₂/kg of EFB via experimental setup. The increase in both steam to biomass ratio and temperature enhanced the production of hydrogen gas. Comparing the results with already published literature showed that the current system enables to produce a high amount of hydrogen from EFB.     

Steam gasification of selected energy crops in a fixed bed reactor

The increasing world's energy demand and environmental concerns related to GHG emissions as well as depleting fossil fuel resources and unstable prices of crude oil and natural gas have caused a renewed interest in renewable energy sources, and in particularly in biomass, as an alternative to fossil fuels. In the paper the results of steam gasification of Salix Viminalis, Miscanthus X Giganteus (MXG), and Andropogon Gerardi in a laboratory-scale fixed bed reactor in the temperature range of 650–900 °C are presented as well as the procedure and results of biomass chars reactivity testing in the process of steam gasification. The highest reactivity R₅₀ in the whole temperature range was observed for MXG. Hydrogen content in the synthesis gas was comparable for MXG and Andropogon Gerardi and lower for Salix Viminalis, while the volumes of the synthesis gas and hydrogen were highest for MXG at all temperatures.     

The impact of carbon sequestration on the production cost of electricity and hydrogen from coal and natural-gas technologies in Europe in the medium term

Carbon sequestration is a distinct technological option with a potential for controlling carbon emissions; it complements other measures, such as improvements in energy efficiency and utilization of renewable energy sources. The deployment of carbon sequestration technologies in electricity generation and hydrogen production will increase the production costs of these energy carriers. Our economic assessment has shown that the introduction of carbon sequestration technologies in Europe in 2020, will result in an increase in the production cost of electricity by coal and natural gas technologies of 30–55% depending on the electricity-generation technology used; gas turbines will remain the most competitive option for generating electricity; and integrated gasification combined cycle technology will become competitive. When carbon sequestration is coupled with natural-gas steam reforming or coal gasification for hydrogen production, the production cost of hydrogen will increase by 14–16%. Furthermore, natural-gas steam reforming with carbon sequestration is far more economically competitive than coal gasification.     

Hydrogen and syngas production from sewage sludge via steam gasification

High temperature steam gasification is an attractive alternative technology which can allow one to obtain high percentage of hydrogen in the syngas from low-grade fuels. Gasification is considered a clean technology for energy conversion without environmental impact using biomass and solid wastes as feedstock. Sewage sludge is considered a renewable fuel because it is sustainable and has good potential for energy recovery. In this investigation, sewage sludge samples were gasified at various temperatures to determine the evolutionary behavior of syngas characteristics and other properties of the syngas produced. The syngas characteristics were evaluated in terms of syngas yield, hydrogen production, syngas chemical analysis, and efficiency of energy conversion. In addition to gasification experiments, pyrolysis experiments were conducted for evaluating the performance of gasification over pyrolysis. The increase in reactor temperature resulted in increased generation of hydrogen. Hydrogen yield at 1000 °C was found to be 0.076 g_gas g_sample⁻¹. Steam as the gasifying agent increased the hydrogen yield three times as compared to air gasification. Sewage sludge gasification results were compared with other samples, such as, paper, food wastes and plastics. The time duration for sewage sludge gasification was longer as compared to other samples. On the other hand sewage sludge yielded more hydrogen than that from paper and food wastes.