Hydrogen Gas Turbine Research Articles

Investigation of absorption characteristics for thermal-load fluctuation using HTTR

ABSTRACTA commercial very high-temperature gas-cooled reactor (VHTR) hydrogen cogeneration system named gas turbine high temperature reactor 300-cogeneration (GTHTR300C) is designed and developed in Japan Atomic Energy Agency (JAEA). Moreover, it has been planned that hydrogen production system and gas turbine system is connect to high-temperature engineering test reactor (HTTR). The reactor system is required to continue a stable and safety operation as well as a stable power supply in the case that thermal-load is fluctuated by the occurrence of abnormal event in the heat utilization system like as the hydrogen production facility. Then, it is necessary to confirm that the thermal-load fluctuation could be absorbed by the reactor system so as to continue the stable and safety operation. The thermal-load fluctuation absorption tests using the HTTR were planned to clarify the absorption characteristics of the HTGR system. However, it is difficult to clarify the phenomenon due to many kinds of fluctuation in nuclear thermal power in the reactor core. Moreover, the actual data regarding how the delay of the temperature response is effective for the reactor system had been gained quantitatively.The thermal-load fluctuation absorption tests without nuclear heating were planned and conducted in JAEA to clarify the absorption characteristic of thermal-load fluctuation mainly by the reactor and by the intermediate heat exchanger (IHX). The absorption characteristics of thermal-load fluctuation can be revealed with sufficient temperature fluctuation. So the tests were conducted with the primary coolant temperature 120 °C which is the start-up temperature of the HTTR. As a result it was revealed that the reactor has the larger absorption capacity of thermal-load fluctuation than the expected one and that the IHX can be contributed to the absorption of the thermal-load fluctuation generated in the heat utilization system in the reactor system. It was confirmed from their results that the reactor and the IHX has effective absorption capacity of the thermal-load fluctuation generated in the heat utilization system. Moreover, the calculation with the safety evaluation code based on RELAP5/MOD3 was performed. It was confirmed that the calculated temperature for the reactor is almost same to the measured one with the new analysis model. On the other hand, it was confirmed that the calculated temperature for the IHX decreased faster than the measured one due to smaller absorption capacity in the calculation model than that in actual one. It can be considered that the calculation for the IHX produces the conservative result. It was summarized that the safety evaluation code can represent the thermal-load fluctuation absorption behavior conservatively.

THERMO economic analysis OF PV and hydrogen gas turbine hybrid power plant of 100 MW power output

The design of a PV-hydrogen gas turbine hybrid power plant is proposed to generate 100 MW electrical load. This electrical power is supplied directly from PV solar panels, and in the case of shortage or lack of solar radiation, it is supplied by a gas turbine power plant working on hydrogen fuel which is produced through using electrolysis of water by a PV generator. The hydrogen produced is stored directly in gas tanks under appropriate pressure. In the case of inability in supplying the load from PV generator, hydrogen fuel will be used through gas turbine. This study is examined in two cases; case (a): the design of the PV power plant based on worst case scenario; which corresponds to the minimum solar radiation and minimum sunshine hours during the year), and case (b): the design of the PV power plant based on average case scenario; which corresponds to the average solar radiation and average sunshine hours during the year. In both cases, the size of the gas turbine power plant and the size of the photovoltaic arrays required for operating day load, the number of water electrolysers, the capacity of hydrogen tanks required for storage purposes; all were calculated. The economic cost in each individual case was analysed taking into account, a profit of 25% of the initial cost. It was found that the price of the electricity produced is 0.12 $/kWh for worst case scenario, and 0.16 $/kWh for the average scenario. The payback period is 13 years and 15 years for the worst and the average scenarios respectively based on 8% interest rate.

The effectiveness of power-generating complexes constructed on the basis of nuclear power plants combined with additional sources of energy determined taking risk factors into account

The effectiveness of combining nuclear power plants equipped with water-cooled water-moderated power-generating reactors (VVER) with other sources of energy within unified power-generating complexes is analyzed. The use of such power-generating complexes makes it possible to achieve the necessary load pickup capability and flexibility in performing the mandatory selective primary and emergency control of load, as well as participation in passing the night minimums of electric load curves while retaining high values of the capacity utilization factor of the entire power-generating complex at higher levels of the steam-turbine part efficiency. Versions involving combined use of nuclear power plants with hydrogen toppings and gas turbine units for generating electricity are considered. In view of the fact that hydrogen is an unsafe energy carrier, the use of which introduces additional elements of risk, a procedure for evaluating these risks under different conditions of implementing the fuel-and-hydrogen cycle at nuclear power plants is proposed. Risk accounting technique with the use of statistical data is considered, including the characteristics of hydrogen and gas pipelines, and the process pipelines equipment tightness loss occurrence rate. The expected intensities of fires and explosions at nuclear power plants fitted with hydrogen toppings and gas turbine units are calculated. In estimating the damage inflicted by events (fires and explosions) occurred in nuclear power plant turbine buildings, the US statistical data were used. Conservative scenarios of fires and explosions of hydrogen-air mixtures in nuclear power plant turbine buildings are presented. Results from calculations of the introduced annual risk to the attained net annual profit ratio in commensurable versions are given. This ratio can be used in selecting projects characterized by the most technically attainable and socially acceptable safety.

Non-gray modeling of radiative heat transfer in hydrogen combustion scenarios

SUMMARY New weighted-sum-of-gray-gases model (WSGGM) parameters for H2O vapor are derived from emissivity correlations in the open literature and presented for use in hydrogen combustion simulations. Predictions employing the new WSGGM are seen to compare favorably against the spectral-line-based WSGGM on benchmark problems as well as in media conditions representative of turbulent hydrogen diffusion flames (Sandia Flame A and a model hydrogen gas-turbine combustor). The Sandia Flame A calculations were performed in a decoupled manner employing experimental measurements of temperature and gas compositions as inputs. The measured temperature variance data were employed to model the turbulence–radiation interactions. A coupled computational fluid dynamic (CFD) calculation was performed to obtain the conditions within the gas-turbine combustor geometry. The observed accuracies of the proposed set of WSGGM parameters in conditions encompassing a wide range of H2O vapor concentrations and temperature non-homogeneities encountered in combustion media make them amenable to implementation in CFD codes. Copyright © 2011 John Wiley & Sons, Ltd.

Electricity systems with near-zero emissions of CO 2 based on wind energy and coal gasification with CCS and hydrogen storage

Emissions from electricity generation will have to be reduced to near-zero to meet targets for reducing overall greenhouse gas emissions. Variable renewable energy sources such as wind will help to achieve this goal but they will have to be used in conjunction with other flexible power plants with low-CO 2 emissions. A process which would be well suited to this role would be coal gasification hydrogen production with CCS, underground buffer storage of hydrogen and independent gas turbine power generation. The gasification hydrogen production and CO 2 capture and storage equipment could operate at full load and only the power plants would need to operate flexibly and at low load, which would result in substantial practical and economic advantages. This paper analyses the performances and costs of such plants in scenarios with various amounts of wind generation, based on data for power demand and wind energy variability in the UK. In a scenario with 35% wind generation, overall emissions of CO 2 could be reduced by 98–99%. The cost of abating CO 2 emissions from the non-wind residual generation using the technique proposed in this paper would be less than 40% of the cost of using coal-fired power plants with integrated CCS.

NO x reduction and NO 2 emission characteristics in rich-lean combustion of hydrogen

Hydrogen is a clean alternative to conventional hydrocarbon fuels, but it is very important to reduce the nitrogen oxides (NO x ) emissions generated by hydrogen combustion. The rich-lean combustion or staged combustion is known to reduce NO x emissions from continuous combustion burners such as gas turbines and boilers, and NO x reduction effects have been demonstrated for hydrocarbon fuels. The authors applied rich-lean combustion to a hydrogen gas turbine and showed its NO x reduction effect in previous research. The present study focused on experimental measurements of NO and NO 2 emissions from a coaxial rich-lean burner fueled with hydrogen. The results were compared with diffusion combustion and methane rich-lean combustion. Significant reductions in NO and NO 2 were achieved with rich-lean combustion. The NO and NO 2 reduction effects by rich-lean combustion relative to conventional diffusion combustion were higher with hydrogen than with methane.

Effect of titania (TiO2) interfacial coating on mechanical properties of carbon-carbon composites

Effect of titania (TiO2) interfacial coating on mechanical properties of carbon-carbon composites

Hydrogen gas-turbine characteristics and hydrogen energy system schemes

A small-sized hydrogen gas-turbine originated from a light-weight car turbo-charger is selected as a practical candidate in constructing an alternative hydrogen energy system element and its energetic characteristic is experimentally examined. Additionally, the potential of alternative hydrogen energy systems including hydrogen gas-turbines are investigated from the standpoint of usage, regeneration, transportation, storage and of wasted heat reutilization including environmental load reduction. Some hydrogen energy schemes are also revealed in this paper.

水素エネルギーシステムと水素の利用

At the present time most of energy is derived from fossil fuels that have a finite reserve. To conserve these fossile sources and retain the present standard of living, a sythetie fuel derived from a renewable energy source must be used. Hydrogen, a fuel that can be produced from water and is expected to emit less pollutants, appears to be the answer. In this article the prospect of hydrogen usage in future is briefly reviewed.The combustion characteristics of hydrogen are quite different from those of methane and other gaseous hydrocarbons. A novel property of hydrogen is its ability to react with oxygen in air when in contact with a catalyst. This property allows the fabrication of catalytic burners, that is, unusual flameless heating devices.Research on hydrogen fueld internal combustion engines has progressed at a high rate in the last several years. Extensive tests on emissions and performance carried out using an injected reciprocating engine have revealed that the hydrogen engine can attain a compression ratio of 10 to 14 and emits less NOx than gasoline engines. The first hydrogen gas turbine was a converted J-57 Pratt and Whitney engine. The stable operation of the J-57 confirmed that conventional gas turbines could be readily adapted to hydrogen fuel. Hydrogen-oxygen fueled rocket engines have been used successfully in recent years for the earth and moon orbits.The efficiency for a modern steam power plan is 40% at the present stage and is not expected to increase significantly as long as the present type of boiler is used. However a new type of burner operating on hydrogen and oxygen would be able to increase this efficiency to 60%. Another new technology for power generation is fuel cell. Its main advantages are high efficiency and low emission level of pollutants. Hydrogen-oxygen fuel cells have shown to function excellently in some special applications particullary in spacecraft. Efforts are being given to produce fuel cells for general use.The industrial-chemical hydrogen usage pattern will not be altered except that the input will be pipelined hydrogen rather than natural gas or naphtha. The conventional blast furnace-converter process for iron production would be changed by appearance of cheap hydrogen.