WO2008092216A1 - Inflatable hood for collecting methane gas in hydroelectric power plants - Google Patents

Abstract

Patent for the invention of an 'inflatable hood for collecting methane gas in hydroelectric power plants', characterized by collecting methane from hydroelectric power plants efficiently, at low cost and can be installed without refits or modification of these plants.

Description

"INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS" .

This present deposit of a Patent for an Invention describes a system, namely an "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS"; its objective is to capture methane gas (CH4) operationally where it is dissolved in the deepest waters of rivers and reservoirs, and released into the atmosphere in hydroelectric power plants, polluting the atmosphere with the greenhouse effect, 21 times worse than in the case of carbon dioxide (CO2), and harness this gas as a major new source of additional energy for use in society.

The most important feature of the present Patent for an Invention is its adaptability and practical execution, which does not introduce any operational change to the hydroelectric power plant, even enabling installation of the device with no interruption to electricity generating operations. Countless studies were published in the 1990s proving a significant presence of methane dissolved in the deep waters of rivers, lakes and reservoirs, above all in tropical and subtropical regions. These studies indicate that the methane in solution in water results from the anaerobic decomposition of organic material by methanogenic bacteria, generating two main gases: methane (ChU) and carbon dioxide (CO2), in the presence of water.

The solubility of the two gases in water (CO2 and CH4) occurs in different forms. While an aqueous solution with CO2 tends naturally to rise and reach the surface, releasing CO2 into the atmosphere, the aqueous solution of methane tends naturally to sink to deeper regions. In the deeper regions water pressure increases and temperature falls. The solubility of methane in water thus increases considerably.

The number of scientific studies published in Brazil and abroad increased considerably after the 1990s, above when it was concluded in 1995 that the quantity of methane released by hydroelectric power plants was significant in hydroelectric power plants in the Amazon region, and it was proved in many studies that emissions of greenhouse gases equivalent to CO2 were higher in terms of the greenhouse effect, than CO2 released by gas-, coal-, or biomass- burning thermoelectrical power plants, to generate the same amount of electricity.

The quantity of methane found in the deeper waters was surprisingly large. In Amazonian power plants, built with the destruction of large flooded swathes of forest to construct dams, it made sense to find large amounts of methane in the analyses, resulting from the anaerobic decomposition of flooded forests, it seemed obvious there would be a high methane content. But when analyzing other hydroelectric power plants, studies showed a considerable methane content dissolved in the deep waters of older power plants, and regions where there had been no forest for several decades continued to be important; we realized that the methane source was much greater than initially imagined.

We found that methane production takes place in the subsoil throughout the entire hydrographical basin, not only in the rivers and reservoirs attached to the hydroelectric power plant. The anaerobic decomposition of roots and other organic matter in the soil by methanogenic bacteria occurs below soil level throughout the entire hydrographical basin whenever the soil is damp, and decomposition of methane occurs; it is absorbed in the subsoil water which sinks lower through the absorption of rainwater, and flows through the immense network of subterranean water tables to the rivers and reservoirs, carrying with it the dissolved methane. Thus, under the Kyoto Protocol, if methane is being released by the turbines, and if there is a simple, efficient method for capturing it, compared with the high cost of fuels and the shortage of gas on the market, it is important for hydroelectric power plants to analyze how much methane their turbines are dissipating and capture it so as to reduce their atmospheric emissions, receiving the financial benefits of the Protocol and also use this source of energy either for electricity generation, to drive vehicles, or for household and industrial use.

The destruction of forests to build dams, and the subsequent decomposition of biomass, producing methane during electricity generation dented the image that hydroelectric power plants are ecologically cleaner and environmentally more correct than thermo-electric power plants. Ecologists and environmentalists are beginning to question licenses to build new hydroelectric power plants. Movements are appearing in the United States to close down some older hydroelectric power plants that had destroyed beautiful forests, and the population, now aware of the effects of methane, wishes to see those forests restored. They are also aware of the need to increase CO2. absorption by forest photosynthesis to reduce atmospheric CO2 content.

An article entitled Coca Cola vs Guarana became well known during the scientific debate, alluding to the overwhelming presence of thermoelectric power plants in the United States and hydroelectric power plants in Brazil, showing which actually polluted more. Brazil has always boasted of its clean energy production through hydroelectric power plants. These studies published in Brazil and abroad, demonstrating the release of methane in turbines, proved unarguably that there is dissolved methane, and showed how the gas comes out of its aqueous solution through depressurization, and several suggested ways of capturing the depressurized gas were published in scientific articles in the public domain; some were even patented on the basis of these publications.

None of these proposals, either published or subsequently patented, could be put to practical use in the existing hydroelectric power plants, which disproves the originality of an invention: the practical applicability of an invention to benefit society is an essential factor in a patent for an invention.

Many hydroelectric power plants in Brazil and worldwide were designed before the problems of solubility of methane in water and the release of methane in the turbines, harming society and the environment through the greenhouse effect, were known. The hydroelectricity industry is now aware of these studies, and of the fact that it is polluting the atmosphere with methane, but it cannot actually capture the gas operationally. Profound design changes to power plants would be needed, or the construction of new specially designed units, or the closure of existing plants to refit them or adapt them, to produce hydroelectric power and simultaneously capture the polluting methane gas. The author has put forward and patented a solution to this problem of the release of methane; he has seen that in practice it is impossible to economically and quickly implement the proposal in an existing hydroelectric power plant without major changes, since hydroelectric power plants are units that cannot be interrupted once they have been designed, built and set in motion, but can only receive preventive maintenance, and need to produce energy in accordance with the hourly demand of consumers, industry and society at large 365 days per year, in the daytime, at night or in the early hours.

Thus, re-studying the problem in depth, and bearing in mind existing constraints in hydroelectric power plants, the author creates and deposits the present Patent for an Invention, an "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", an innovative concept that is different from the scientific publications put forward to date, and from the patents deposited on the basis of published scientific studies, and is characterized by being practically feasible, possible to install without necessitating alterations to the design or operation of hydroelectric power plants existing today in Brazil or elsewhere in the world, so that they can extract the methane released by the depressurization of the water flowing through the turbines, ceasing to pollute the atmosphere and the environment, and producing gas energy that can be used by society either as fuel or for household or industrial purposes, or in vehicular transport or to generate electricity in hydroelectric power plants. The hydroelectric power plants benefit from the advantages offered by the Kyoto Protocol upon installation of the present "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", the subject of the present Patent for an Invention.

Since it is an innovative practical solution that can easily be applied in hydroelectric power plants existing today, at low cost, and rapidly installed, depolluting the atmosphere on a large scale, and since it can benefit from the resources of the Kyoto Protocol, we have added the merits of the novelty and applicability of the idea to its practical use, and we request that this Patent for an Invention be granted in the due form of law and under the present Industrial Protection regulations.

We know that in practice hydroelectric power plants vary greatly in their construction, in countless factors, above all in the difference in level, and the volume of water available, the type of turbine (Pelton, Kaplan and Francis) in the electricity generator, the number of turbines and generators, the construction of the dam, the reservoir, all of which depend on the geography of the region, the methane content in the reservoir, the depth at which water is collected upstream from the turbine, the discharge from the turbines, and the spillways of the hydroelectric power plant, among other factors that the design of the plant, as well as the design, construction, installation and operation of the collecting hood and the optional fins, also the subject of this Patent for an Invention. To better explain the concepts of the present Patent for an Invention, we present below a practical example of the application of this Patent, without this explanation in any way limiting the application, except in regard to the type of hydroelectric power plant demonstrated, where

Figure 1 shows a perspective image of a hydroelectric power plant in operation, with a cross section of the dam at the level of a system with one turbine, generator, discharge system, and in the subsequent figure the remaining turbines in parallel. In the background image, the spillway of the same power plant, draining excess water, which flows down from the high part of the dam to the river without generating electricity. Figure 2 shows a perspective of the same plant, with the inflatable hood for collecting gas, made out of reinforced, impermeable plastic tarpaulins, mounted over the entire turbine discharge area, downstream from the dam, built in such a way that all the methane released from the aqueous solution bubbles up to the surface as a result of depressurization, when going through the turbine, under the hood, that collects the gas and pipes it through a duct to a purifying and de-humidification unit. The inflatable gas-collection hood can be mounted on buoys and suitably fixed to enable assembly as in the figure. Figure 3 shows the inflatable hood system assembled on buoys, along with the valves and the intake duct.

In figure 1 , we have a concrete dam (1) maintaining a head of water (4), that flows through the trash rack (2) through the penstock (3) to the turbine (5) coupled to the generator (6). The water that is thus collected under pressure drives the turbine (5), which converts the potential energy of the water

(4) into rotational mechanical energy, which in turn drives the generator (6), converting mechanical energy into electrical energy. The water, after transferring its potential energy to the turbine, (5) undergoes depressurization, and is discharged downstream of the dam by the duct (7), through the water flow (8), which when depressurized releases methane in the form of bubbles.

The released methane is absorbed by the atmosphere and contributes significantly to the greenhouse effect. The power plant has several sets of generators installed in parallel as per figure 1. The machine room (12) houses the set of turbines and generators. The spillway (9) discharges excess water not being used for electricity generation through the water discharge flow (10).

In figure 2, we show a perspective of the same hydroelectric power plant, with the inflatable hood assembled (13). The inflatable hood (13) covers the entire surface of the water of the hydroelectric power plant encompassing the turbine discharge (5), through the discharge ducts (7), releasing downstream from the dam (1) the flow of depressurized water (8) that is releasing the dissolved methane owing to the sudden depressurization of the water. All the methane is released inside the inflatable hood (13) and is transferred along the tube (14) to a de-humidification and purification system that is demonstrated...

In figure 3, we can observe the set of: inflatable hood for collecting the methane, the methane is controlled by the valve (17), is deposited in the tube (14) on the buoys (18); the buoys (18) have safety straps attached to them (19) and weights (20) so that they stay in the water. A survey of the presence of methane carried out with the support of the

Brazilian government showed that all hydroelectric power plants release methane into the atmosphere to a greater or lesser extent, polluting it. With the invention of the present Patent for an "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", it is now possible to capture this hydrogas or methane from deep waters simply, efficiently and cheaply, substantially reducing atmospheric pollution and benefiting from Kyoto Protocol financial resources, and with the production of a new fuel to competitively meet the demand for natural gas consumption.

Claims

1. "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", is characterized by collecting methane that is dissolved in deep waters of hydroelectric power plants, extracted by sudden depressurization in electricity-generating turbines, polluting the atmosphere and contributing to an increase in the greenhouse effect.

2. "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", is characterized by the fact that it can be installed and set in motion to collect methane without changing the design of construction of existing power plants, or forcing their temporary closure during installation and operation.

3. "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", is characterized by significantly reducing emissions of methane into the atmosphere at hydroelectric power plants, thus significantly contributing to a reduction in the greenhouse effect on this planet.

4. "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", is characterized by reducing methane emission into the atmosphere and by benefiting from the financial resources of the Kyoto Protocol.

5. "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", is characterized by enabling tthe generation of clean electricity in terms of atmospheric pollution and by enalbing a new source of production of gas energy in the hydroelectric power plant, increasing its capacity or increasing its business.

6. "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", is characterized by returning to hydroelectric power plants their image as plants that produce clean, non- polluting, long-term energy. "INFLATABLE HOOD FOR COLLECTING METHANE GAS IN HYDROELECTRIC POWER PLANTS", is characterized by quickly and cheaply offering all environmental and economic advantages and those of increase production of clean energy.