Meyer Steinberg

Fossil fuel decarbonization technology for mitigating global warming

Abstract It has been understood that production of hydrogen from fossil and carbonaceous fuels with reduced CO2 emission to the atmosphere is key to the production of hydrogen-rich fuels for mitigating the CO2 greenhouse gas climate change problem. The conventional methods of hydrogen production from fossil fuels (coal, oil, gas and biomass) include steam reforming and water gas shift mainly of natural gas (SRM). In order to suppress CO2 emission from the steam reforming process, CO2 must be concentrated and sequestered either in or under the ocean or in or underground (in aquifers, or depleted oil or gas wells). Up to about 40% of the energy is lost in this process. An alternative process is the pyrolysis or the thermal decomposition of methane, natural gas (TDM) to hydrogen and carbon. The carbon can either be sequestered or sold on the market as a materials commodity or used as a fuel at a later date under less severe CO2 restraints. The energy sequestered in the carbon amounts to about 42% of the energy in the natural gas resource which is stored and not destroyed. A comparison is made between the well developed conventional SRM and the less developed TDM process including technological status, efficiency, carbon management and cost. The TDM process appears to have advantages over the well developed SRM process. It is much easier to sequester carbon as a stable solid than CO2 as a reactive gas or low temperature liquid. It is also possible to reduce cost by marketing the carbon as a filler or construction material. The potential benefits of the TDM process justifies its further efficient development. The hydrogen can be used as a transportation fuel or converted to methanol by reaction with CO2 from fossil fuel fired power plant stack gases, thus allowing reuse of the carbon in conventional IC automobile engines or in advanced fuel cell vehicles.

Modern and prospective technologies for hydrogen production from fossil fuels

Abstract A study is presented assessing the technology and economics of hydrogen production by conventional and advanced processes. Six conventional processes are assessed: (1) steam reforming of natural gas, (2) partial oxidation of residual oil, (3) gasification of coal by the Texaco process, (4) gasification of coal by the Koppers-Totzek process, (5) steam-iron process and (6) water electrolysis. The advanced processes include (1) high temperature electrolysis of steam, (2) coal gasification and electrochemical shift, (3) integrated coal gasification and high temperature electrolysis, (4) thermal cracking of natural gas and (5) the HYDROCARB thermal conversion of coal. Thermochemical water splitting, high energy nuclear radiation, plasma and solar photovoltaic-water electrolysis and by-product hydrogen from the chemical industry are also briefly discussed. It is concluded that steam reforming of methane is the most economic near-term process among the conventional processes. Processes based on conventional partial oxidation and coal gasification are two to three times more expensive than steam reforming of natural gas. New gas separation processes, such as pressure swing adsorption, improve the economics of these conventional processes. Integration of hydrogen production with other end-use processes has an influence on the overall economics of the system. The advanced high temperature electrochemical systems suffer from high electrical energy and capital cost requirements. The thermochemical and high energy water splitting techniques are inherently lower in efficiency and more costly than the thermal conversion processes. The thermal cracking of methane is potentially the lowest cost process for hydrogen production. This is followed closely by the HYDROCARB coal cracking process. To reach full potential, the thermal cracking processes depend on taking credit for the clean carbon fuel by-product. As the cost of oil and gas inevitably increases in the next several decades, emphasis will be placed on processes making use of the worlds reserve of coal.

Production of hydrogen and methanol from natural gas with reduced CO2 emission

Abstract The thermal decomposition of natural gas forms the basis for the production of hydrogen with reduced CO 2 emission. The hydrogen can be used to reduce CO 2 from coal-fired power plants to produce methanol which can be used as an efficient automotive fuel. The kinetics of methane decomposition is studied in a one inch diameter tubular reactor at temperatures between 700 and 900 °C and at pressures between 28 and 56 atm. The Arrhenius activation energy is found to be 31.3kcal/mol of CH 4 . The rate increases with higher pressures and appears to be catalyzed by the presence of carbon particles formed. The conversion increases with temperature and is equilibrium limited. A thermodynamic study indicates that hydrogen produced by methane decomposition while sequestering the carbon produced requires the least amount of process energy with zero CO 2 emission. Application to methanol synthesis by reacting the hydrogen with CO 2 recovered from coal burning power plant stack gases can significantly reduce CO 2 from both the utility and transportation sectors. Published by Elsevier Science Ltd on behalf of the International Association for Hydrogen Energy.

Hynol—An economical process for methanol production from biomass and natural gas with reduced CO2 emission

Abstract The Hynol process is proposed to meet the demand for an economical process for methanol production with reduced CO2 emission. This new process consists of three reaction steps: (a) hydrogasification of biomass, (b) steam reforming of the produced gas with additional natural gas feedstock, and (c) methanol synthesis of the hydrogen and carbon monoxide produced during the previous two steps. The H2-rich gas remaining after methanol synthesis is recycled to gasify the biomass in an energy neutral reactor so that there is no need for an expensive oxygen plant as required by commercial steam gasifiers. Recycling gas allows the methanol synthesis reactor to perform at a relatively lower pressure than conventional while the plant still maintains high methanol yield. Energy recovery designed into the process minimizes heat loss and increases the process thermal efficiency. If the Hynol methanol is used as an alternative and more efficient automotive fuel, an overall 41% reduction in CO2 emission can be achieved compared to the use of conventional gasoline fuel. A preliminary economic estimate shows that the total capital investment for a Hynol plant is 40% lower than that for a conventional biomass gasification plant. The methanol production cost is

Control of carbon dioxide emissions from a power plant (and use in enhanced oil recovery)

0.43/gal for a 1085 million gal/yr Hynol plant which is competitive with current U.S. methanol and equivalent gasoline prices. Process flowsheet and simulation data using biomass and natural gas as cofeedstocks are presented. The Hynol process can convert any condensed carbonaceous material, especially municipal solid waste (MSW), to produce methanol.

Production of synthetic methanol from air and water using controlled thermonuclear reactor power—I. technology and energy requirement

The design of a compact, environmentally acceptable, carbon dioxide-diluted, coal-oxygen-fired power plant is described. The plant releases no combustion products to the atmosphere. The oxygen for combustion is separated in an air liquefaction plant and the effluent nitrogen is available for use in oil well production. Recycled carbon dioxide mixed with oxygen replaces the nitrogen for the combustion of coal in the burners. The carbon dioxide produced is used in enhanced oil recovery operations and injected into spent wells and excavated salt cavities for long-term storage. The recovery of CO2 from a coal-burning power plant by this method appears to have the lowest energy expenditure and the lowest by-product cost compared to alternative removal and recovery processes.

Preliminary design and analysis of recovery of lithium from brine with the use of a selective extractant

Abstract Methanol synthesis from carbon dioxide, water and nuclear fusion energy is extensively investigated. The entire system is analyzed from the point of view of process design of various processes. The main potential advantage of a fusion reactor (CTR) for this purpose is that it provides a large source of low cost, environmentally acceptable electric power based on an abundant fuel source. Carbon dioxide is obtained by extraction from the atmosphere or from sea water. Hydrogen is obtained by electrolysis of water. Methanol is synthesized by the catalytic reaction of carbon dioxide and hydrogen. The water electrolysis and methanol synthesis units are considered to be technically and commercially available. The benefit of using air or sea water as a source of carbon dioxide is to provide an essentially unlimited renewable and environmentally acceptable source of hydrocarbon fuel. Extraction of carbon dioxide from the atmosphere also allows a high degree of freedom in plant siting. The significant contribution of the present study is the evaluation of various methods of separation of carbon dioxide from air or sea water. Eight different methods of extraction of carbon dioxide from air are analyzed: (1) absorption and stripping of air by water at atmospheric pressure, (2) absorption and stripping of air by water at atmospheric pressure with a cooling tower as part of the absorption unit, (3) absorption and stripping of air by water at higher pressure, 20 atm, (4) absorption and stripping of air by methanol at 20 atm and −80°F, (5) removal of water vapor by adsorption on molecular sieves and subsequent extraction of carbon dioxide by refrigeration, (6) removal of water vapor by compression refrigeration and subsequent extraction of carbon dioxide by refrigeration, (7) absorption and stripping of air by a dilute aqueous potassium carbonate solution, and (8) removal of water vapor by adsorption on molecular sieves and adsorption/desorption of carbon dioxide from dry air by molecular sieves. A method of stripping of carbon dioxide from sea water is also presented. In order to compare these newly developed methods for CO2 separation with other conventional non-fossil sources of carbon, the calcination of limestone is also examined. For the extraction of carbon dioxide from air, the process of absorption/stripping of air by dilute potassium carbonate solution is found to require the least amount of energy. The total energy required for methanol synthesis from these sources of carbon dioxide is 3.90 kWh(e)/1b methanol of which 90% is used for generation of hydrogen. The process which consumes the greatest amount of energy is the absorption/stripping of air by water at high pressure and amounts to 13.2 kWh(e)/1b methanol. A subsequent paper will consider the important topic of economic evaluation.

Environmental Control Technology for Atmospheric Carbon Dioxide

Lithium requirements for battery and controlled thermonuclear fusion reactor uses in the next few decades may exceed the current availability of the mineral and brine reserves. It is thus prudent to search for new reserves and resources to satisfy these and other lithium applications in the future. It has been reported that the lithium content of smackover oilfield waters ranges in the order of 100–500 mg/l, and thus could represent a substantial reserve. A method is proposed to extract lithium from this source.

History of CO2 greenhouse gas mitigation technologies

The impact of fossil-fuel use in the United States on worldwide CO2 emissions and the impact of increased coal utilization on CO2 emission rates are assessed. The aspects of CO2 control are discussed, as well as the available CO2 control points (CO2 removal sites).

Synthetic carbonaceous fuels and feedstocks from oxides of carbon and nuclear power

Much effort has been expended in the last several decades on the science of radiative gases in the atmosphere and particularly CO2 as a greenhouse gas. Only in the last few years has interest grown in the technology of CO2 mitigation. A discussion is given on the early development of CO2 mitigation concepts which has led to a surge in this activity worldwide and especially in Japan. The history of CO2 greenhouse gas mitigation is short and is actually being made at this First International Conference on the subject.