The application of nuclear process heat for hydrogasification of coal
Abstract
Hydrogasification is the conversion of coal with hydrogen to methane. Because coal and water only are primarily available for gasification purposes, the hydrogen required for methane production has to be produced by the gasification process. This requires heat at a high temperature level which can be supplied by a high temperature reactor as nuclear process heat. In this paper two process variants are described for hydrogasification of lignite with nuclear process heat. The design data of a draft for commercial-scale plants are given. Also, the pilot plant of Rheinische Braunkohlenwerke AG for hydrogasification of coal in the fluidized bed is described.
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Cited by (12)
Hydrogen production pathways for Generation-IV reactors
2023, Handbook of Generation IV Nuclear Reactors: A GuidebookHydrogen is experiencing a growing momentum worldwide as a clean versatile energy solution. Even though it is the most abundant element in the universe, hydrogen rarely exists in its primary form, and is mostly available in water and organic compounds. Nuclear hydrogen production technologies are believed to take part in securing large portion of the growing hydrogen demand for a clean and affordable energy future. Coupling hydrogen and nuclear plants serves several industries where large quantities of hydrogen are required. The utilization of nuclear thermal energy for hydrogen production provides an important pathway for combating climate change and provides an alternate, environmentally benign method away from dependency on the conventional carbon-based hydrogen production technologies. This chapter tackles some of the promising technologies of hydrogen production available for near-term deployment to provide sustainable large-scale production and discusses their feasibility to be coupled with nuclear power plants based on Generation-IV reactor designs.
Results from the operation of a semi-technical test plant for brown coal hydrogasification
1984, Nuclear Engineering and DesignThe Rheinische Braunkohlenwerke AG has built and has been operating a semi-technical pilot plant for hydrogasification of coal in fluidized bed. The objective is to develop a coal gasification process with hydrogen for producing directly substitute natural gas. Between 1976 and 1982, the semi-technical pilot plant was operated for about 27000 h under test conditions, more than 12000 h of which were under gasification conditions. During this time, approximately 1800 metric tons of dry coal were gasified. The longest coherent operational phase under gasification conditions was 748 h in which 86.4 metric tons of dry lignite were gasified. Carbon gasification rates up to 82% and methane contents in the dry raw gas (free of N2) up to 48 vol% were obtained. A detailed evaluation of the test results provided extensive information on the influence of operational parameters on the efficiency dates of the gasifier. Moreover, several components were tested for which no operational experience had previously been gained; these were newly developed devices, e.g. the inclined tube for feeding coal into the fluidized bed. Within the framework of scale-up to large-scale coal gasification plants, a pilot plant having a capacity of about 10 metric tons of dry brown coal per hour was commissioned in late 1982. On May 30, 1983, coal was for the first time fed into the plant. The present test planning provides for tests with brown coal till the end of 1985. This could be followed by the use of other coals, such as hard coal.
Nuclear process heat-application to coal gasification
1981, Nuclear Engineering and DesignThe high temperature gas cooled reactor has achieved peak coolant temperatures from 775 to 950°C, depending on the core design. These temperatures are sufficiently high to consider the HTR as a source of heat for several large industrial processes. In this article the application is to a coal gasification process which produces a mixture of carbon monoxide and hydrogen as the key product. The gasifier system itself is coupled to the HTR via a catalyzed fluidized bed coal gasifier operating at 700°C and producing methane. The feed to this gasifier is a mixture of carbon monoxide, hydrogen and steam with the stoichiometry chosen to effect an overall athermal reaction so that no heat is directly transferred into the gasifier. Its hydrogen supply is generated by steam reforming the methane produced using the direct HTR heat. This indirect system has advantages in terms of its final product, indirect heat transfer and ultimately in the savings of approximately 40% of the coal which would otherwise have been assumed in an all-coal process producing the same final product.
Possibilities and state of development of nuclear coal gasification processes
1980, Chemical Engineering ScienceBy the development work of the last years and the successful operation of a experimental reactor it is clear today that the high temperature reactor is capable to produce heat at a temperature level of 950° C. This heat can be used in different industrial processes, especially for coal gasification. The processes of hydrogasification and steam gasification have been tested in large pilot plants in the past and are thought to be feasible today in connection with use of nuclear energy. In this paper the main aspects of these processes, of the nuclear reactor and of the heat exchanger system are presented and discussed. Questions like the choice and qualification of high temperature materials, the tritium contamination of the product gas and the aspects of licensing are key points of the technical realisation of nuclear process heat applications. This paper tries to summarize some of these results of the development programm of the PNP-Project (Prototyp Nukleare Prozeβwärme) in Germany, which is a common Projekt of German Companies financed by the government.
In situ formation of protective oxide scales as measured by their inhibiting effect on the high temperature hydrogen permeability of heat exchanger materials
1977, Thin Solid FilmsThe importance of protective oxide scales as barriers against hydrogen and tritium permeation in nuclear process heat systems is demonstrated. Since it is not possible to predict the overall permeation rate under real conditions, an experimental facility was constructed to carry out these measurements. The results of the first 2000 h run demonstrate a considerable decrease in hydrogen permeation owing to the growth of protective oxide scales.
A kinetic analysis suggests a parabolic time dependence. The long term residual permeation rate must be attributed to imperfections in the oxide layers. Interference effects from a certain oxidation of the primary gas surfaces are also considered. Finally, some remarks are made on relationships between hydrogen permeation and metallurgical diagnostics.
RESULTS FROM THE OPERATION OF A SEMI-TECHNICAL TEST PLANT FOR BROWN COAL HYDROGASIFICATION.
1984, Massachusetts Institute of Technology, Fluid Mechanics Laboratory, PublicationThe Rheinische Braunkohlenwerke AG has built and has been operating a semi-technical pilot plant for hydrogasification of coal in fluidized bed. The objective is to develop a coal gasification process with hydrogen for producing directly substitute natural gas. Between 1976 and 1982, the semi-technical pilot plant was operated for about 27000 h under test conditions, more than 12000 h of which were under gasification conditions. During this time, approximately 1800 metric tons of dry coal were gasified. The longest coherent operational phase under gasification conditions was 748 h in which 86.4 metric tons of dry lignite were gasified. Carbon gasification rates up to 82% and methane contents in the dry raw gas (free of N2) up to 48 vol% were obtained. A detailed evaluation of the test results provided extensive information on the influence of operational parameters on the efficiency dates of the gasifier. Moreover, several components were tested for which no operational experience had previously been gained; these were newly developed devices, e.g. the inclined tube for feeding coal into the fluidized bed. Within the framework of scale-up to large-scale coal gasification plants, a pilot plant having a capacity of about 10 metric tons of dry brown coal per hour was commissioned in late 1982. On May 30, 1983, coal was for the first time fed into the plant. The present test planning provides for tests with brown coal till the end of 1985. This could be followed by the use of other coals, such as hard coal.