WO2013089544A1

WO2013089544A1 - Biogas production system

Info

Publication number: WO2013089544A1
Application number: PCT/MX2012/000049
Authority: WO
Inventors: Alejandro GARZA GALICIA
Original assignee: Instituto Superior Autonomo De Occidente, Ac
Priority date: 2011-12-14
Filing date: 2012-05-08
Publication date: 2013-06-20
Also published as: MX2011013482A

Abstract

The invention relates to a biogas production system for farms or any facilities that generate animal waste, comprising: a biodigester for producing biogas from the waste; a drain which receives the treated organic waste; a heat source for heating the waste, the biogas being produced in the digester; a filter for removing impurities from the biogas produced; a biogas storage tank; and an electricity generator. The system is easy to install, expand and transport and the biogas produced can be used, inter alia, in ovens, water heaters and electricity generators.

Description

BIOGAS PRODUCTION SYSTEM

TECHNICAL FIELD OF THE INVENTION This invention relates to the field of development of renewable energy production, more specifically with a biogas production system. This type of energy is produced from processes that use the resources and natural effects of our environment, among which we can mention the sun, wind and water currents, organic matter from crops or waste also called biomass. The use of biomass for energy production is a process with which a mechanism can be provided so that farms and ranches adequately handle animal waste, satisfy a proportion of the need for the gas they consume and guide them towards sustainable development.

BACKGROUND OF THE INVENTION

The energy development of most countries has been based on the exploitation of hydrocarbons, including Mexico; society, industrial and commercial sectors demand increasing amounts of energy to meet their needs, the world economy is based on the exploitation of this type of fuel, however this fossil source has a life time that scientists have already determined and unfortunately the transformation scheme for the use of other types of energy sources has not yet been established.

At present, renewable energy sources constitute a potential for development in different fields of application; Solar energy, generated by wind and water currents, is in common use in many countries using them at the level of the house, rural and industrial sectors. Another of the renewable energies available is that generated from organic waste, also known as biomass; different fuels can be generated from this matter, such as biodiesel, ethanol and biogas among the most important, however, its potential utilization to date is without giving the results so that the urban, rural and industrial sectors find a profitable business in the production of energy through this source. In different countries, biogas production systems have been developed from animal waste for the own use of the farms, basically for the kitchen as in China and several countries in Asia; In Mexico there have been different experiences in the rural sectors to produce energy from this waste; However, due to lack of knowledge, accessibility to technology, continuity in projects and lack of financing according to the conditions of small producers, this source has been little exploited.

The production of biogas from the fermentation of waste is a biological process in which organic matter naturally degrades under conditions of absence of air. The process is carried out in three phases: hydrolysis, acidification and methanization; In these processes the bacteria find a means to develop and produce a mixture of gases, whose highest concentration corresponds to methane (CH ₄ ) and carbon dioxide (CO ₂ ) and in small concentrations hydrogen sulfide (H ₂ S), water vapor and ammonia (NH ₃ ). Because it contains a greater amount of methane, this fermentation product can be used as a heating fuel, its calorific value being slightly less than that of natural gas or Pressure Liquefied (LP) due to the impurities that accompany methane, however This disadvantage can be compensated by the fact that the raw material for these plants to function is a byproduct of the operations of these sites and that in some cases their management and disposal prove to be a serious problem. The potential for the use of animal waste is very high due to the large number of farms and small livestock and poultry ranches, considering that on average a small number of head of cattle can generate up to 490 kilograms of manure per day, in the Most of the cases are wasted and this waste is not given adequate disposition, so that later they become a health problem and potential focus of diseases.

In Mexico the rural sectors and specifically the small ranches and farms are limited to make large investments to manage the waste produced by the animals and take advantage of the benefits they generate; firstly due to a lack of knowledge in this technology and a lack of diffusion in the use of renewable sources. Biogas is at a disadvantage due to its low availability for large consumers in urban areas and industrial sectors, however, in rural areas or places far from cities where the lack of fuel at affordable prices and the supply of electricity is Limited, it provides guidelines for this energy source to be an opportunity for development through a biogas production system such as the present invention.

In different sectors, small-scale biogas production systems have been developed, the first ones built from a rural civil works with basic connections and storage without safety specifications. In other countries, biogas production systems with large capacities and automated systems for the feeding of waste that make energy use in these systems and increase initial investments are presented on the market. The models presented in the literature and on different web pages show prototypes with an academic vision, the necessary process engineering development is needed to establish the efficient operation from a collection of waste, mixing and introduction thereof, gas production and waste treatment on departure. The models of small-scale biogas production systems that are presented in different sources of information are fixed facilities, they cannot be moved to other farms, without first re-building the ditch, the plastic materials of the biodigester's cover, in some cases does not resist weathering conditions, they are punctured, leaky and Degrade in a short time. In many cases the operation of the farm or ranch is not taken into account to define the arrangement of the biogas production system. The present invention has the advantage of being movable and scalable to the dimensions and capacities required by the farmer without the need to make special ditches or drains.

Many of the biogas production systems that have been built have a system such as that indicated in patent No. MX 2008014147, which installs a flexible bag system for the production of biogas in the biodigester, which when exposed, animals from the farm they can drill and let out the biogas produced; This problem is solved by the present invention with rigid tanks preventing animals from being able to drill it, that there is a considerable loss of biogas and that the system stops operating until it is repaired.

Patent document No. EC SP088861 which presents a flexible biogas containment system shows the deficiency of being pierced by farm animals, a situation that the present invention solves with the rigid tank system.

There are different models of biogas production systems with additional facilities, some such as the one reported in patent No. ES2340514 (T3) has pumping systems and couplings in modules that increase the number of equipment, the required space and the initial cost, The present invention is not equipped with equipment that consumes electrical energy or fossil external energy, thus avoiding an increase in environmental pollution due to these consumptions.

In the patent No. ES 2233667 (T3) the biodigester has a flat heating system in the tank wall, as well as a liquid drainage device, the present invention has within the biodigester a coil that is connected to a solar heater , which supplies the hot water for temperature regulation during the reaction and the drain of the residue is through a gravity tube. Currently, the level of energy production is one of the most important variables in the economy of the countries, since it largely depends on industrial development and economic certainty so that entrepreneurs risk investing in projects in different sectors, As a potential for economic development and energy transformation, biogas produced through a biogas production system such as the one proposed by this invention can produce a significant amount as an indicator in national energy balances, thus making the country energy attractive speaking, as well as the economic benefits that would derive to the small farm sectors and their productive chains.

To raise these mentioned energy production rates, clean energies are required, which do not affect the natural wealth of the planet, which lower the rates of greenhouse gas production, as well as reduce dependence on oil and its derivatives and at the same time be promoters of sustainable development of peoples. The biogas production system of the present invention treats the waste and does not allow these to cause methane emission that is almost 4 times more lethal than carbon dioxide, in the same way if the residues are left outdoors with the rains the risk that will infiltrate the lower layers of the subsoil and contaminate the groundwater, a situation that is diminished with the present invention while promoting the use of renewable energies.

Small milk producers when installing a biogas production system can find a clean energy generation option for their consumption, a means to reduce their operating costs and make their small businesses more competitive with respect to large companies, as well as direct them to a sustainable path for the benefit of their quality of life.

Another fundamental aspect that seeks to satisfy the biogas production system is the technification of the field and farms, with simple systems, basic, without sophisticated systems, that the user can operate with an elementary training and at the same time can give a general maintenance without the need of the visit of the specialized technicians. OBJECT OF THE INVENTION

The object of the invention is to provide a system capable of producing significant amounts of biogas without affecting the natural wealth of the planet, lowering the rates of greenhouse gas production, as well as reducing dependence on oil and its derivatives.

BRIEF DESCRIPTION OF THE FIGURES

The characteristic details of this novel biogas production system are clearly shown in the following description and in the accompanying and illustrative drawings that accompany it, as well as in an illustration thereof, following the same reference signs to indicate the parts and the figures shown. Figure 1 shows the general arrangement of the biogas production system.

Figure 2 is a cross-section of the biodigester (1) where the inlet tube (2) of waste and the discharge tube (3) of fermented substrate, the coil (4), together with the discharge flange (5) ) of biogas and the hot water injector (6), the discharge of warm water current (7) from the coil (4) and the temperature meter (8).

Figure 3 is a perspective view of the drain (9) of the biogas production system, it shows the drain mesh (10) and the strainer (11) that make it up.

Figure 4 is a top view of the heat source (12) of the biogas production system, here the outlet pipe of the hot water heat source (13) is shown, the inlet pipe of the heat source (14) of warm water and the stop valve (15).

Figure 5 is the side section of the filter (16) of the biogas production system, therein the filter injector (17) and the discharge of the filter (18) can be seen.

Figure 6 shows a cross section of the storage tank

(19) of biogas, the inlet pipe to the storage tank (20), the relief valve (21) and the discharge pipe of the biogas storage tank (22) can be observed.

Figure 7 is a side view of the electric power generator (23) in which the biogas injector (24) can be seen.

DETAILED DESCRIPTION OF THE INVENTION

Below is the list of parts that make up the biogas production system.

I. - Biqdigestor

2.- Inlet tube

3. - Discharge tube

4. - Coil

5. - Discharge flange

6. - Hot water stream injector

7.- Discharge of warm water current

8. - Temperature meter

9. - Drainer

10. - Drainer mesh

I I. - Porous strainer

12.- Heat source

13. - Heat source outlet pipe

14. - Heat source inlet pipe

15. - Stop valve 16. - Filter

17. - Filter injector

18. - Filter discharge

19. - Storage tank

20.- Storage tank inlet pipe

twenty-one . - Relief valve

22. - Storage tank discharge pipe

23. - Electric power generator

24. - Biogas injector

With reference to figure 1, the biogas production system consists of:

A biodigester (1), which is a tank with a screw cap on its upper or closed part, preferably made of polymer, which has at least one inlet side (2) on which one enters the organic waste of the animals; the inlet tube (2) is located in the lower lateral part of the biodigester (1) and is configured in such a way that it extends to the bottom of said biodigester (1) allowing the incoming waste to move the substrate towards at least one tube discharge (3), which is located on the opposite upper side of the inlet tube (2) at a 45 ° angle that functions as a trap to maintain the substrate level within the biodigester (1); This substrate is deposited in a drain (9) and through a drain mesh (10) placed at the top of the drain (9) and a porous strainer (1 1) located at the bottom of the drain mesh (10 ) as shown in figure 3, separate moisture from the outgoing substrate for later use as a compost or fertilizer; Inside the biodigester (1) there is a coil (4) housed from the top to the bottom of the biodigester (1) to homogenize the heat distribution, which is fed with water by a hot water current injector (6) located in the upper part of the biodigester (1), the water flows through a discharge of warm water (7) located in the lower part of the biodigester (1) as indicated in figure 2, the coil (4) allows to raise and maintain the substrate temperature to start the process of fermentation of the organic waste, this temperature is recorded by a temperature meter (8) placed in the central lateral part of the digester (1); The heat to carry out this process is supplied by a heat source (12), this heat source can be a solar heater, a boiler, a bank of electric resistances or some fuel that produces heat, the heat raises the temperature of the water that is displaced by difference in densities to an outlet pipe of the heat source (13) to feed the hot water injector (6), this current is controlled through a bypass valve (15) located in The heat source outlet pipe (13) and the water that passes through the coil (4) is discharged to a heat source inlet pipe (14) that is on the side opposite the outlet pipe of the heat source (13) as shown in figure 4, in order to recirculate the water and avoid its waste; this process makes the temperature inside the biodigester (1) homogeneous and allows the biogas generated by natural decomposition to ascend to a discharge flange (5) located at the top of the biodigester (1); through which the biogas is led to a filter (16) by means of a filter injector (17) located on the lower side of the filter (16), the filter (16) that is configured with staggered lime barriers and iron as shown in figure 5, allows to reduce the impurities that the biogas contains to exit through a discharge of the filter (18) located on the upper side of the filter (16) towards an inlet pipe to the storage tank (20 ) where it is stored in a storage tank (19) said tank is a rigid container which in its upper part is provided with a relief valve (21) as shown in figure 6, which dislodges the biogas if the maximum operating pressure For the use of biogas, the storage tank (19) has a discharge pipe of the storage tank (22) placed on top of the storage tank (19) which leads the biogas to an electric power generator (23 ) through a biogas injector (24) as shown in figure 7, for later combustion. PREFERRED EMBODIMENT OF THE INVENTION

In experimental tests at the laboratory level, the biogas production system generates volumes of biogas with low concentrations of hydrogen sulfide allowing the electric power generator to operate and produces a substrate with quality to be used as a fertilizer or as a base for composts.

The system prevents the contamination caused by the waste from being spilled into the atmosphere and the aquifers, as well as the proliferation of open-air flies, infectious foci and bad odors.

The following example is presented as an additional guide, for the person skilled in the art, in no case should it be considered as a limitation of the invention.

The biodigester is loaded by the inlet tube with a mixture of waste and water in proportions of 1: 4 in the case of cattle, in each type of waste there is a relationship for the proper operation of the digester, initially it is loaded in a proportion that increases the volume within the biodigester gradually until its capacity is completed in approximately 20 days, at which time the stable production of biogas begins, in the same way it begins to send the circulation of hot water through the hot water stream injector and its temperature is controlled until reaching approximately 35 ° C by opening the control valve as the volume increases, once continuous biogas begins to occur, it is conducted through the filter, this device reduces impurities by reacting the hydrogen sulfide acid contained in the biogas adsorbing it in its body of traps of iron and lime, the gas passes to the storage tank to arrange it in the usual applications of heating in stoves, water heaters, process equipment and for the production of electrical energy. With the waste load, a volume equal to that entered was discharged through the discharge tube, this substrate falls on the mesh and the drain strainer to remove moisture, this substrate is placed in the sun and once dry it can be used as fertilizer and as a base for composting, the water that falls from the drain can be used to prepare the waste that will enter the biodigester. In experiments at the laboratory level, it has been recorded that the concentration of hydrogen sulfide is less than 0.01% and it is physically observed that the combustion equipment has little or little erosion, in the same way the calorific value of the biogas has been obtained compared to the LP gas is 64% of the latter.

Claims

CLAIMS Having sufficiently described our invention, we consider it as a novelty and therefore claim our exclusive property, contained in the following clauses:

1.- An integrated biogas production system for processing organic wastes from farm animals, characterized in that it comprises:

• a biodigester to produce biogas from organic waste;

• a drain that receives the organic waste processed by the biodigester;

• a source of heat, which allows the temperature inside the biodigester to be raised, to ferment organic waste and biogas production, the heat source is connected to the biodigester by means of a hot water stream injector and a discharge of warm water current;

• a filter, which reduces the impurities of the biogas generated in the fermentation process of organic waste within the biodigester; · A storage tank that allows to store the biogas free of impurities that comes from a discharge of the filter; Y

• an electric power generator, which works with the biogas generated and stored in the storage tank.

2. - The biogas production system of claim 1, wherein the biodigester is a tank configured to seal in its upper part.

3. - The biogas production system of the preceding claims wherein the biodigester has at least one inlet in the lower lateral part, which allows the organic waste to enter the tank, in the upper lateral part of the biodigester has at least a discharge tube that allows to move the organic waste already processed to pass to the drain; a coil, connected to the hot water injector and to the discharge of warm water; a temperature meter; and a discharge flange located in the upper part of the tank, which allows the generated biogas to pass to the filter.

4. - The biogas production system of the preceding claims characterized in that the hermetic closure of the biodigester is by means of a screw cap.

5. - The biogas production system of the preceding claims wherein the inlet tube is configured such that it extends to the bottom of said biodigester allowing the incoming waste to move the substrate towards the discharge tube.

6. - The biogas production system of the preceding claims wherein the discharge tube has an angle of 45 ° which functions as a trap to maintain the level of organic waste inside the tank.

7. - The biogas production system of the preceding claims wherein the coil is configured to be distributed from the top of the tank to the bottom of the tank, in order to maintain the temperature inside the tank in a homogeneous manner.

8. The biogas production system of the preceding claims wherein the drain has a mesh in its upper part and a strainer located in the lower part of the drain.

9. The biogas production system of the preceding claims wherein the strainer is porous.

10. The biogas production system of the preceding claims wherein the heat source is allowed to be a solar heater, a boiler, electrical resistors or any type of fuel that produces heat.

11. - The biogas production system of the preceding claims wherein the filter is internally structured by lime and iron barriers.

12. - The biogas production system of the preceding claims wherein the filter barriers are staggered.

13. - The biogas production system of the preceding claims wherein the storage tank is a rigid container which in its upper part is provided with a relief valve, which relieves the biogas if the maximum operating pressure is exceeded, said Storage tank also has a discharge pipe placed on top of the tank, which leads the biogas to the electric power generator.

14. - The biogas production system of the preceding claims wherein the electric power generator is allowed to be by means of engine or combustion turbine.