Methane environmental impacts

Some petroleum geologists believe that there may be more methane trapped in hydrates than what is associated with natural gas reserves. However, as an energy source, there is considerable uncertainty whether this methane can ever be recovered safely, economically, and with minimal environmental impact. The Russians have experimented with the use of antifreeze to break down hydrates at some onshore locations in Siberia. But perhaps a more promising approach would be to pipe warm surface water to the bottom to melt the hydrates, with a collector positioned to convey the gas to the surface. Another approach might be to free methane by somehow reducing the pressure on the methane hydrates. 

Hydro-electricity is the most developed renewable resource worldwide, even if it has to face social and environmental barriers [29]. In fact societal preferences are difficult to predict, while hydro-sites are often difficult to reach, which results in high transmission and capital investment costs. These are difficult to be accepted by private power companies. The global economic hydropower potential ranges between 7000 and 9000 TWh per year. Particularly mral communities without electricity appear to be convenient for small (<10 MWe), mini- (<1 MWe), and micro- (<100 kWe) scale hydro schemes. They have low environmental impacts, and generation costs are around 6-12 c/kWh. Emissions of GHG linked with hydro-electricity operation are due to flooding of land upstream of a dam that can imply a loss of biological carbon stocks and can produce methane emissions due to vegetation decomposition. 

Halon - As employed in the fire protection industry, a gaseous fire suppression agent. Halon is an acronym for halogenated hydrocarbons, commonly bromotrifluoromethane (Halon 1301) and bromochlorodifluoro-methane (Halon 1211). Considered obsolete for fire protection purposes due to a possible environmental impact to the Earth s atmospheric ozone layer and beginning to be phased out or eliminated. 

Compare using methane from natural gas with using methane from methane hydrates in terms of environmental impact and efficiency. You will need to do some research to find out extraction methods for each source of methane. 

Williams, A. Mitchell, C. 1994. Methane emissions from coal mining. In Hester, R. E. Harrison, R. M. (eds) Mining and Its Environmental Impact. Royal Society of Chemistry, London, 97-109. 

The recovered sulfur industry exists primarily as a result of the necessity of removing sulfur values from hydrocarbon fuels before combustion so that sulfur emissions to atmosphere are reduced. In the case of sour gas, the principal source of recovered sulfur, the product that results from recovery of the sulfur is clean-burning, non-polluting methane. In the case of refineries handling high sulfur crude the product is low sulfur gasoline and oils. Thus every ton of sulfur recovered is a ton that is not added to the atmosphere. The recovery process itself however, is also the subject of optimization and recent developments in recovery efficiency have further ensured that the environmental impact in the immediate vicinity of these desulfurization facilities will be minimized. 

The production of hydrogen from methane is important because it has a low environmental impact. The production of hydrogen via steam reforming has a H2/C02 ratio of 4 (Table 1), the lowest C02 impact of any fossil fuel source. The dc plasma system produces a H2/C02 ratio of about 1000 in the effluent stream. However, CO is a major product of the system. If the water-gas shift reaction were used to convert all of the produced CO into C02 via reaction [5], the resulting H2/C02 ratio would be approximately 9 for either system. This value is still considerably better than that of other fossil fuels, including steam reforming. 

In addition to carbon sequestration, technologies that would provide economic benefits include those that enhance oil recovery, produce coalbed methane, and maintain pressures in depleted gas reservoirs to avoid surface subsidence. Currently, companies in the United States sell one billion standard cubic feet of C02 each day, or approximately the C02 output from one conventional coal-fired electric power plant with a power capacity of 2300 MW. This C02 is used economically and with little or no environmental impact for approximately 70 enhanced oil recovery projects and for other industrial applications. Pipeline specifications for C02 quality, pipeline safety issues, and custody of the C02 have a base of industrial experience that goes back to the 1970s. Today, there are operating C02 pipelines of up to 760 mm (30 inches) in diameter and 640 km (400 miles) in length (Fig. 6-6). 

The logic of attacking BST for fear of increasing antibiotic residues is flawed. The previously cited OMB study even reported on a favorable environmental impact statement with BST use. This is based on the fact that BST-induced increase in milk production per cow would decrease the total number of cows in our country. This could result in less pollution through decreased use of fertilizers, less cow manure, and less methane production. Why don t environmentalists quote these results ... 

There has been a good deal of study of the polyhalogenated methanes in hydrogen atom abstraction reactions toward hydroxyl (HO ) and chlorine radicals. These reactions are involved in both the atmospheric destruction of such compounds as well as their involvement in ozone depletion. Information is needed about these reactions to model the environmental impact of the compounds. 

Cheng, Y.-P., Wang, L. Zhang, X.-L. (2011) Environmental impact of coal mine methane emissions and responding strategies in China, bitemational Journal of Greenhouse Gas Control, 5, 157 166. 

The most important benefit gained from following tbe Methane Run is its low environmental impact. During plant startup, Methane Run emits CO2 of around 67% less than the Normal procedure. Similarly, the Methane Run shutdown emits 80% less than the Normal procedure. 

The LCA analysis first performs an inventory analysis that involves data collection and calculation procedures to quantify relevant inputs and outputs of the entire system defined within the system boundaries. This inventory is followed by an environmental impact assessment, which quantifies and categorises the inventory analysis results into environmental impacts. For demonstration purposes. Table 1 shows a list of the inventory emissions to air and the impact analysis of these emissions. The impact analysis step converts the inventory results into equivalents of a selected reference substance for each impact category such as emitting 1kg of methane is equivalent to 11kg of CO2 for global warming potential and 1kg of HF is equivalent to 1.6kg of SO2 for acidification. 

A fuel cell power generation system consists of several components besides the fuel cell such as a fuel processor and a power conditioner/inverter. The fuel processor is the first step of the conversion of fuel into an electrical current Typically, a fuel processor utilizes a combination of steam reforming (SR) and partial oxidation (POX) methods to convert hydrocarbons (methane, natural gas) into the pure hydrogen necessary as input to the fuel processor. During this process, the fuel processor also should strip the input gas of its pollutants such as carbon and carbon monoxide. The fuel processor is one of the areas in which the greatest environmental threat can occur because of this. There are a number of other considerations to be taken into account when examining the environmental impact and life cycle assessment of fuel cell power generation system such as axillary equipment and their economic and environmental impact (Kordesch and Simader 1995 van Rooijen 2006 Tromp 2002). 

Of these, oil and gas reservoirs are the most attractive. Active oil wells can utilize the carbon dioxide in tertiary recovery, and CO2 can be used as a sweep gas to promote the production of methane from certain types of coal deposits. Furthermore, because these geological formations have already demonstrated their ability to hold oil and gas, there are no obvious environmental consequences to long-term storage in such locations. The same cannot be said for deep oceans and deep saline geological formations. Those sites, although promising, hold potential uncertainties in retention and environmental impacts. 

---