Three-reactors chemical looping process for hydrogen production

This paper analyzes a novel process for producing hydrogen from natural gas, based on chemical looping (CL) techniques, allowing for intrinsic capture of carbon dioxide. The core of the process consists of a three-reactors CL system, where iron oxide particles are circulated to: (i) oxidize natural gas (thus providing, after cooling and water condensation, a CO₂ stream ready for sequestration), (ii) reduce steam, to produce hydrogen as the final product of the process, (iii) consume oxygen from an air stream, to sustain the thermal balance of the system.

The process is intrinsically very attractive, because it directly produces hydrogen and CO₂ from natural gas, by means of a process simpler than the conventional technologies with CO₂ capture capabilities. Hence, a significant potential for investment cost reduction can be anticipated.

However, to fully exploit the system potential, an efficient energy recovery from the gaseous streams exiting the reactors must be arranged, taking into account power and steam production needed to support internal consumptions. Therefore, after an introduction clarifying the concept and the scope of the system, as well as its basic chemistry, this paper presents a discussion of two plant configurations, including different integration levels with power production (fired gas turbine (GT) vs. unfired turbocharger) and/or heat recovery steam production methods (also considering steam compression devices). A comparison with “proven technology” plants, based on steam reforming, is also carried out. Due to the lack of reliable estimates of the investment costs for components to be developed from scratch (CL reactors), the analysis is limited to the thermodynamic and technological aspects. Results show, however, that an impressive potential exists for CL systems for hydrogen production, thus deserving substantial R&D activities in the near future.     

Long term forecasting of natural gas production

Natural gas is an important energy source for power generation, a chemical feedstock and residential usage. It is important to analyse the future production of conventional and unconventional natural gas. Analysis of the literature determined conventional URR estimates of 10,700–18,300 EJ, and the unconventional gas URR estimates were determined to be 4250–11,000 EJ. Six scenarios were assumed, with three static where demand and supply do not interact and three dynamic where it does. The projections indicate that world natural gas production will peak between 2025 and 2066 at 140–217 EJ/y (133–206 tcf/y). Natural gas resources are more abundant than some of the literature indicates.     

Forecasting the growth of China’s natural gas consumption

The use of natural gas in China is still relatively immature, as gas production only supplies a low percentage of the domestic energy system. In contrast, Chinese economy mainly relies on coal with a 67% share of the total primary energy supply. The environmental impact from this high coal dependence is significant and planners have sought for cleaner energy sources. Natural gas is both cleaner and generally more efficient than coal and gas consumption is rising quickly due to these facts.The growth tendency indicates that natural gas will become an important substitution for coal in some parts of the Chinese primary energy consumption. To quantify this tendency, this paper uses a system dynamics model to create a possible outlook. The results show that the gas consumption in China will continue to increase fast to 89.5 billion cubic meters in 2010; 198.2 billion cubic meters in 2020, before finally reach 340.7 billion cubic meters in 2030.Scenario analysis is used to assess the accuracy of the results. Finally, this paper gives policy suggestions on natural gas exploration and development, infrastructure constructions and technical innovations to promote a sustainable development of China’s natural gas industry.     

Catalytic thermochemical reactor/receiver for solar reforming of natural gas: Design and performance

The advantages of thermochemical conversion of concentrated solar energy using catalytic processes are discussed. The design of a solar volumetric thermochemical reactor/receiver (TCRR) with catalytic absorber, method for synthesis of catalytically activated ceramics, and preparation of catalytic absorber have been described. The prototype TCRR was tested in the high flux solar furnace at the DAC, Cologne by using the dioxide reforming of methane. The tests were performed to check the main concept of the TCRR design and catalytic absorber, to study the influence of solar flux distribution, the reagent flows and their ratio on the productivity or conversion, determine the reagent's conversion depending on the focal point disposition with respect to the absorber, and to study the efficiency of the thermochemical conversion. The chemical and total efficiencies of the CO₂–methane conversion were calculated using the experimentally measured concentrations of the reaction products. The highest overall efficiency achieved in these experiments was 30% with the Ni–Cr catalytic absorber.     

LNG (liquefied natural gas): A necessary part in China's future energy infrastructure

This paper presents an overview of the LNG industry in China, covering LNG plants, receiving terminals, transportation, and applications. Small and medium scale LNG plants with different liquefaction processes have already been built or are being built. China's first two LNG receiving terminals have been put into operation in Guangdong and Fujian, another one is being built in Shanghai, and more are being planned. China is now able to manufacture LNG road tanks and containers. The construction of the first two LNG carriers has been completed. LNG satellite stations have been built, and LNG vehicles have been manufactured. LNG related regulations and standards are being established. The prospects of LNG in China are also discussed in this paper. Interesting topics such as small-scale liquefiers, LNG cold energy utilization, coal bed methane liquefaction, LNG plant on board (FPSO – floating production, storage, and off-loading), and LNG price are introduced and analyzed. To meet the increasing demand for natural gas, China needs to build about 10 large LNG receiving terminals, and to import LNG at the level of more than 20 bcm (billion cubic metre) per year by 2020.     

The emerging hydrogen economy and its impact on LNG

Hydrogen is gaining prominence as a critical tool for countries to meet decarbonisation targets. The main production pathways are based on natural gas or renewable electricity. LNG represents an increasingly important component of the global natural gas market. This paper examines synergies and linkages between the hydrogen and LNG values chains and quantifies the impact of increased low-carbon hydrogen production on global LNG flows. The analysis is conducted through interviews with LNG industry stakeholders, a review of secondary literature and a scenario-based assessment of the potential development of global low-carbon hydrogen production and LNG trade until 2050 using a novel, integrated natural gas and hydrogen market model. The model-based analysis shows that low-carbon hydrogen production could become a significant user of natural gas and thus stabilise global LNG demand. Furthermore, commercial and operational synergies could assist the LNG industry in developing a value chain around natural gas-based low-carbon hydrogen.     

Ceria-coated replicated aluminium sponges as catalysts for the CO-water gas shift process

A study on the use of chemical conversion coating as a preparative technique for foam-based structured catalysts, in the water gas shift reaction, is presented. The results showed a significant correlation between the textural properties of the structure and the preparation technique, highlighting how chemical conversion coating is a suitable technique for highly porous structures. In the first part of the paper, the performance of two structured catalysts obtained by coating commercial aluminium foams, with different porosity, was compared. The activity tests suggested that diffusion phenomena occurred in the case of the uncompressed foams. These results were confirmed by evaluating the performance of a catalyst obtained by coating a compressed 5 PPI pore size commercial aluminium foam, which showed much higher activity, at the same contact time, with respect to the catalyst obtained with the corresponding non-compressed foam. Finally, the performance of a catalyst obtained by coating an aluminium sponge, synthesized by the replication technique, was compared to that of a catalyst obtained by coating a compressed 40 PPI pore size aluminium foam. The higher activity of the sponge-based catalysts confirmed the dependence of the activity on the textural properties of the structure: X-ray computed tomography images highlighted the narrow distribution of the pore sizes and the presence of “bottleneck type” connections in the sponge structure, which are beneficial for the activity of the catalyst.     

European energy security: The future of Norwegian natural gas production

The European Union (EU) is expected to meet its future growing demand for natural gas by increased imports. In 2006, Norway had a 21% share of EU gas imports. The Norwegian government has communicated that Norwegian gas production will increase by 25–40% from today's level of about 99 billion cubic meters (bcm)/year. This article shows that only a 20–25% growth of Norwegian gas production is possible due to production from currently existing recoverable reserves and contingent resources. A high and a low production forecast for Norwegian gas production is presented. Norwegian gas production exported by pipeline peaks between 2015 and 2016, with minimum peak production in 2015 at 118 bcm/year and maximum peak production at 127 bcm/year in 2016. By 2030 the pipeline export levels are 94–78 bcm. Total Norwegian gas production peaks between 2015 and 2020, with peak production at 124–135 bcm/year. By 2030 the production is 96–115 bcm/year. The results show that there is a limited potential for increased gas exports from Norway to the EU and that Norwegian gas production is declining by 2030 in all scenarios. Annual Norwegian pipeline gas exports to the EU, by 2030, may even be 20 bcm lower than today's level.     

Turkey's natural gas policy

This article deals with natural gas policy of Turkey. Natural gas became important in the 1980s. In recent years, natural gas consumption has become the fastest growing primary energy source in Turkey. Natural gas becomes an increasingly central component of energy consumption in Turkey. Current gas production in Turkey meets 3% of the domestic consumption requirements. Natural gas consumption levels in Turkey have witnessed a dramatic increase, from 4.25 Bcm (billion cubic meters) in 1991 to 21.19 Bcm in 2003. Turkish natural gas is projected to increase dramatically in coming years, with the prime consumers expected to be industry and power plants. Turkey has chosen natural gas as the preferred fuel for the massive amount of new power plant capacity to be added in coming years. Turkey has supplied main natural gas need from Russian Federation; however, Turkmen and Iranian gas represent economically sound alternatives. Turkey is in a strategically advantageous position in terms of its natural gas market. It can import gas from a number of countries and diversify its sources. Turkey's motivation for restructuring its natural gas ownership and markets stems from its desire to fulfill EU accession prerequisites in the energy sector.     

LNG汽车发展现状及相关问题分析

近两年我国LNG汽车实现了快速发展,本文介绍了我国LNG汽车产业发展现状,分析了LNG汽车的特点及发展优势,并综合我国LNG汽车产业目前发展面临的问题及未来发展的不确定因素,结合我国宏观经济形势及天然气行业发展趋势,分析了LNG汽车产业的发展趋势。     

The future of U.S. natural gas production,use, and trade

Two computable general equilibrium models, one global and the other providing U.S. regional detail, are applied to analysis of the future of U.S. natural gas. The focus is on uncertainties including the scale and cost of gas resources, the costs of competing technologies, the pattern of greenhouse gas mitigation, and the evolution of global natural gas markets. Results show that the outlook for gas over the next several decades is very favorable. In electric generation, given the unproven and relatively high cost of other low-carbon generation alternatives, gas is likely the preferred alternative to coal. A broad GHG pricing policy would increase gas use in generation but reduce use in other sectors, on balance increasing its role from present levels. The shale gas resource is a major contributor to this optimistic view of the future of gas. Gas can be an effective bridge to a lower emissions future, but investment in the development of still lower CO₂ technologies remains an important priority. International gas resources may well prove to be less costly than those in the U.S., except for the lowest-cost domestic shale resources, and the emergence of an integrated global gas market could result in significant U.S. gas imports.     

Natural gas based hydrogen production with zero carbon dioxide emissions

A novel process flowsheet is presented that co-produces hydrogen and formic acid from natural gas, without emitting any carbon dioxide. The principal technologies employed in the process network include combustion, steam methane reforming (SMR), pressure swing adsorption, and formic acid production from CO₂ and H₂. Thermodynamic analysis provides operating limits for the proposed process, and the use of reaction clusters leads to the synthesis of a feasible process flowsheet. Heat and power integration studies show this flowsheet to be energetically self-sufficient through the use of heat engine and heat pump subnetworks. Operating cost/revenue studies, using current market prices for natural gas, hydrogen and formic acid, identify the proposed design’s operating revenue to cost ratio to be 9.29.     

Conceptual design and system analysis of a poly-generation system for power and olefin production from natural gas

In this paper, a novel poly-generation system for olefin and power production from natural gas is proposed, which integrates hydrocarbon production and the combined cycle power generation. Economic and technological evaluation based on the internal rate of return (IRR) and exergy efficiency is performed. The energy integration results in the proposed poly-generation system for simultaneous production of chemical products (ethylene and propylene) and electricity being more thermodynamically efficient and economically viable than single purpose power generation and chemical products production plants. IRR and exergy efficiency of the proposed poly-generation system are higher than that of natural gas methanol to olefin (NGMTO) system, 18.9% and 49.9%, respectively. The biggest exergy destruction segments, their causes, and possible measures for improvement are investigated simulation and thermodynamic analysis. To analyze the effect of unreacted syngas recycle on the exergy efficiency and economic gains from the proposed poly-generation system, its thermoeconomic optimization model is built by combining economic with thermodynamic analysis. Optimization analysis shows that when 78% of the unreacted syngas is recycled back to the reactor in the methanol synthesization process, the thermoeconomic performance of the poly-generation system is at its optimum.     

Exploring the production of natural gas through the lenses of the ACEGES model

Due to the increasing importance of natural gas for modern economic activity, and gas's non-renewable nature, it is extremely important to try to estimate possible trajectories of future natural gas production while considering uncertainties in resource estimates, demand growth, production growth and other factors that might limit production. In this study, we develop future scenarios for natural gas supply using the ACEGES computational laboratory. Conditionally on the currently estimated ultimate recoverable resources, the ‘Collective View’ and ‘Golden Age’ Scenarios suggest that the supply of natural gas is likely to meet the increasing demand for natural gas until at least 2035. The ‘Golden Age’ Scenario suggests significant ‘jumps’ of natural gas production – important for testing the resilience of long-term strategies.     

Hydrogen and LNG production from coke oven gas with multi-stage helium expansion refrigeration

Here we propose a novel cryogenic system to simultaneously produce liquid hydrogen (LH₂) and liquefied natural gas (LNG) from coke oven gas. The coke oven gas, simplified as a mixture of methane and hydrogen, directly enters the cryogenic system. Due to the very low temperature of liquid hydrogen, helium is selected as the refrigerant, and the energy needed for the liquefaction is supplied by a multi-stage helium expansion refrigeration system. The high-purity liquid hydrogen and LNG products are obtained with the help of a cryogenic distillation column. The whole cryogenic process is simulated with the Aspen HYSYS software to determine the parameters of each process point and key component. We found that the process is able to produce LH₂ and LNG of very high purity. Using the power consumption of the product liquefaction as the major performance parameter for the analysis, optimum parameters of the multi-stage helium expansion liquefaction process could be found. The results show that the proposed system can achieve a methane recovery rate of 97.9% and a hydrogen recovery rate of 99.7% with acceptable energy consumption.     

Natural gas exergy recovery powering distributed hydrogen production

Natural gas transmission systems often involve a pressure reduction process that does not make use of the mechanical exergy available in the gas. A moderate fraction of this work potential can be extracted using turbo-machinery. This paper quantifies the energy that can be extracted from various pressure reduction facilities using an expander coupled to an electric generator. Produced electricity can either be routed back into the electric distribution grid or used to produce small amounts of hydrogen. A problem with this process is the variable nature of the gas flow rate entering the facility. For the pressure reduction station data used in this study, the gas flow rate may drop to below one quarter of the peak, reducing the efficiency and production rates of the coupled components. A model has been created to analyze these seasonal variations and to produce generalized functions that allow the hydrogen production potential of any pressure reduction facility to be approximated. If the coupled technologies operate at their assumed peak efficiencies, then electricity can be extracted from the pressure reduction with 75% exergetic efficiency and hydrogen can be produced with 45% exergetic efficiency.     

Low carbon hydrogen production in Canada via natural gas pyrolysis

Large scale, low cost, and low carbon intensity hydrogen production is needed to reduce emissions in the energy and transportation sectors. We present a techno-economic analysis and life cycle assessment of natural gas pyrolysis technologies for hydrogen production, with carbon black (CB) as a co-product. Four designs were considered based on the source of heat to the pyrolysis system, the combustion medium, and use of carbon capture (CC) technology. The oxygen-fired-CB design with CC is the most attractive from financial and environmental perspectives, superior to a conventional steam methane reformer (SMR) process with CC. The estimated pre-tax minimum hydrogen selling prices for the pyrolysis technologies range between $1.08/kg and $2.43/kg when natural gas (NG) costs $3.76/GJ. Key advantages include near-zero onsite GHG emissions of the oxygen-fired-CB design with CC and up to 41% lower GHG emissions compared to the SMR + CC process. The results indicate that natural gas pyrolysis may be a feasible pathway for hydrogen production.     

The estimation of fugitive gas emissions from hydrogen production by natural gas steam reforming

In recent years, a significant amount of interest has been directed towards using hydrogen as an alternative source of energy to fossil fuel. Even though hydrogen is emission free in its end use; the production of hydrogen itself requires energy and may cause process emissions including fugitive emissions from various sources, mainly the piping equipment and fittings. The emissions, even though not as large as stack emissions, they may still pose risks to the environment and health especially to the workers within the plant area. This paper presents the estimation of fugitive emissions from hydrogen production process via natural gas steam reforming. Firstly, the natural gas steam reforming process was simulated before the fugitive emissions of carbon monoxide (CO) and greenhouse gases (GHGs), such as methane (CH₄) and carbon dioxide (CO₂) in the process were estimated. Then, the consequent global warming potential (GWP) and the associated health risks due to the emissions were evaluated. A comparison of the GHG fugitive emissions with other sources of GHG emissions over the hydrogen production life cycle was also performed. Methane (CH₄) recorded the highest rate of fugitive emissions contributing to the greatest GWP. On the other hand, CO₂ represented the total stack emissions contributing to 100% of the total GWP. The concentrations of the gases emitted as fugitive emissions (CH₄, CO₂ and CO) in the process area are below the threshold exposure limit indicating that the plant environment is safe for workers daily exposures to the emitted gases.     

The production of crude oil and natural gas

This paper is directed at examining the impact of changing prices on the level of production of crude oil and natural gas in the United States. By using a cross-correlation test for unidirectional causality it is clearly demonstrated that, for both crude oil and natural gas, domestic production is affected by changing prices. The implications are clear. The decontrol of the price of crude oil and the deregulation of natural gas prices will lead to additional production in the near term.     

Pathways to low-cost clean hydrogen production with gas switching reforming

Gas switching reforming (GSR) is a promising technology for natural gas reforming with inherent CO₂ capture. Like conventional steam methane reforming (SMR), GSR can be integrated with water-gas shift and pressure swing adsorption units for pure hydrogen production. The resulting GSR-H2 process concept was techno-economically assessed in this study. Results showed that GSR-H2 can achieve 96% CO₂ capture at a CO₂ avoidance cost of 15 $/ton (including CO₂ transport and storage). Most components of the GSR-H2 process are proven technologies, but long-term oxygen carrier stability presents an important technical uncertainty that can adversely affect competitiveness when the material lifetime drops below one year. Relative to the SMR benchmark, GSR-H2 replaces some fuel consumption with electricity consumption, making it more suitable to regions with higher natural gas prices and lower electricity prices. Some minor alterations to the process configuration can adjust the balance between fuel and electricity consumption to match local market conditions. The most attractive commercialization pathway for the GSR-H2 technology is initial construction without CO₂ capture, followed by simple retrofitting for CO₂ capture when CO₂ taxes rise, and CO₂ transport and storage infrastructure becomes available. These features make the GSR-H2 technology robust to almost any future energy market scenario.