WO2011120183A2

WO2011120183A2 - Transportable system for generating and injecting oxygen in situ for fish cages in the sea

Info

Publication number: WO2011120183A2
Application number: PCT/CL2011/000019
Authority: WO
Inventors: Rodrigo LAZARRAGA MUÑOZ
Original assignee: Oxzo S.A.
Priority date: 2010-03-30
Filing date: 2011-03-24
Publication date: 2011-10-06
Also published as: CA2793288C; CL2010000300A1; NO341634B1; GB2491085A; CA2793288A1; NO20121042A1; WO2011120183A3; GB2491085B; GB201216791D0

Abstract

The invention relates to a transportable system for generating oxygen in situ and injecting industrial levels of oxygen for fish cages in the sea, said system comprising a floating pontoon-like platform having a floatability of at least 50 tons and able to be towed in the open sea, in which said system generating 93-95% purity oxygen is contained. Said transportable system also comprises a system that generates and distributes electricity, providing electrical energy to the components of the oxygen-generating system which, in turn, essentially comprises means for generating pressurised air, means for generating pressurised oxygen, means for compressing and accumulating high-pressure oxygen, and means for controlling the oxygen-generating system.

Description

PORTABLE OXYGEN GENERATION AND INJECTION SYSTEM IN SITU FOR FISH CAGES AT SEA

FIELD OF APPLICATION OF THE INVENTION

The present invention aims to improve the productive yields in the fish cycle, more specifically to a portable oxygen generation and injection system at industrial levels for fish cages in the sea, oriented mainly to the aquaculture industry, collection centers, among others.

DESCRIPTION OF PRIOR ART

Oxygen from seawater is derived mostly from the air, so it is accompanied by the gases that normally make up this mixture. Since oxygen is more soluble in water than nitrogen, it is found in a greater proportion than in air. The volume of oxygen in seawater is approximately 25 to 30 times less than the volume of the same element in the air.

The oxygen dissolves in the water by simple absorption, which is accentuated by the swell that removes the water and puts new layers in contact with the air, which favors the diffusion process. Therefore the oxygenation of water is directly related to the agitation of the sea. Also the richness of oxygen is related to salinity, the greater the salinity corresponds to a smaller amount of oxygen.

Another factor that influences the absorption of oxygen by water is temperature. For this reason in the open seas the oxygen richness decreases from the poles to the equator

Oxygen is the fundamental element for life, required by fish and plants to carry out vital processes such as the oxidation of proteins, Carbohydrates and fats. This allows the disintegration of these substances to generate a consequent release of energy used for the vital functions of beings. If the oxygen level is not enough for the ecosystem, the plants will split the fructose and glucose into carbon dioxide and alcohol, that is, in a short time, their cells will die.

Whenever the ecosystem demands more oxygen than the surface exchange can provide, it is necessary to provide oxygen by external or artificial means.

Oxygen, food and water are three fundamental parameters in fish farming. In particular, the availability of O ₂ in water has a direct effect on crop yield. Trends towards high fish densities will result in adequate concentrations of O ₂ dissolved in the water necessary for the development of the fish. The injection of O ₂ has as main objective to increase the level of dissolved oxygen in the fish culture ponds. Its concentration will determine, in most of the times, the production yield. The greatest benefits are reflected in the increase in the rate of feed conversion, providing more efficient use of food, improving fish growth and giving them greater resistance to pathogenic organisms, reducing stress and mortality and optimizing use of facilities reaching higher densities.

All of the above, forces to have oxygen generating systems capable of injecting said gas into seawater to optimize the breeding of fish, such as salmon, for example. It is known that during the fish production cycle there is high mortality associated with low oxygen, especially during the summer due to different factors such as algae blooms, anoxic currents, cage biomass, etc. Many of these problems are undetectable because the casualties occur at night.

Currently, a drop in OD (oxygen demand) is evidenced as specific events, since constant and online OD monitoring systems are not used in the culture cages, and these specific events are solved, moving cylinders or thermos containers of oxygen, which from the logistic point of view is little operational when the centers are very far apart, in addition, the amount of 0 ₂ to be transferred is not an industrial quantity that can solve problems on a large scale.

An alternative solution can be found in patent documents such as document FR 2735463, of the owner SPIE CITRA ILE DE FRANCE, entitled "Independent or semi-independent water oxygenation system", which describes a pontoon with air compressors that feed micro diffusers ceramics that are suspended in the water by wires. However, this document is a system to produce air that is injected into the water. Here there is clearly a sustainative difference because when injecting air that has 20% oxygen and not a 93% oxygen flow, it also only has air containers and not an oxygen generation system as in the case of the present invention, where an oxygen generation and injection system is provided which is mounted on a pontoon comprising a shed, which inside contains diesel accumulation means, means to compress air, means to dry the air, filter media, generation means of electricity, oxygen generating means, accumulation means: high pressure designed to contain oxygen, and special high pressure compressor means for the air, which work in synchronized form by means of an internal control system that allows to make decisions of how much to produce, store and inject oxygen. Patent document US 4,906,359, of the COX JR BERTHOLD V holder, entitled "Solar activated water aeration station" which describes a water aeration station for injecting air at a certain depth. This station It includes a floating platform and solar panels, which are to power an engine and a pump, and it also has means to provide an appropriate inclination to maximize solar energy. However, solar panel systems have a natural limitation that prevents them from scaling the design to an industrial scale. A conservative calculation would indicate that for the requirement of solar panels for a system such as that of the present invention it would be of the order of 2,000 m ² of panels with hundreds of batteries. The batteries are not considered in both cases and only feed during daylight hours. In addition, this system, like the previous one, is only to produce air that is injected into the water.

JP 56073528, of the holder MIYAKE TAKAMURA, entitled "Oxygen supply device used in fish farm or the like", which describes an oxygen injection system through cylindrical diffusers comprising a plurality of narrow holes. However, oxygen is connected to an air compressor and an oxygen generation system mounted on a pontoon is not described.

I

The oxygenation and oxygen injection system of the present invention, differs from what exists in the market for its ability to generate OD in situ, also has the characteristic of injecting continuously without having major logistical problems in industrial quantities.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a block diagram of the system of the present invention.

Figure 2 shows a plan view of the system of the present invention with all the equipment comprising the system and a distribution mode. Figure 3 shows a diagram of the arrangement of the present invention regarding the distribution of connection of fish cages in the sea. DETAILED DESCRIPTION OF THE INVENTION

The on-site oxygen generation and injection system (100) is arranged on a floating platform, called a pontoon, with side walls and roof, to house inside the system (100) of the present invention. This pontoon has a buoyancy of at least 50 tons and is capable of being towed in the open sea.

The oxygen generation and injection system (100), which generates oxygen at 93-95% purity, comprises an electricity generating and distribution system, which provides electrical power to the components of this oxygen generating system, where The latter basically comprises pressurized air generating means, pressurized oxygen generating means, high pressure oxygen compression and accumulation means and control means of the oxygen generation system.

The electricity generator and distributor comprises means of accumulating fuel, preferably diesel, from storage tanks (302) located inside the pontoon that allows the operation of the oxygen generation and injection system (100) for extended periods of time. This storage tank (302) considers at least 15,000 liters of capacity, level meter and a pump (s) to deliver the diesel to the generator sets. The electricity distribution system considers a force board (201) and switching board (202) to distribute the energy produced by the generation system to the oxygen production line. While the electronic system contains the protections and distribution system for handling and switching on all control electronics. In addition, it includes a battery bank (203) and UPS (204) with the ability to keep the electronic control systems running for 24 hours and with an optimal and regulated level of voltage and frequency. The pressurized air generating means essentially comprise compressor means (102), which in a preferred embodiment is a reciprocal compressor that generates an air flow at a pressure of about 620.5-792.9 KPa (90-115 psi ); drying means (103), which by cooling extract the water that may come in the compressed air; filter media (104), which in a preferred embodiment, comprise 2 filters and a centrifugal trap that remove the suspended particles, the drops of oil that can be dragged from the compressor and finally the drops of water that leave the compressor as a complement to the dryer action; and air accumulator means (105) that serve to act as a buffer of the pressure fluctuations that occur, since the oxygen generation process has an air consumption that is not stable over time.

Pressure oxygen generating means essentially comprise a system called "Pressure Swing Adsorption Generator" (106) and a low pressure oxygen accumulator (107). The system "Generator by Pressure Swing Adsorption" (106), takes air under pressure and passes it to a molecular sieve bed containing a specific adsorbent for nitrogen, so that at the exit of said bed there is an enriched flow of oxygen at 93-95%. When the first bed is saturated, the air passage of the latter closes and the second bed is filled with a process identical to the first. The first bed then begins to drop the nitrogen adsorbed by the substrate into the atmosphere. This process is controlled by an internal PLC of the equipment. While, at the exit of the oxygen generation, there is a low pressure oxygen accumulator (or tanks), with the purpose of damping the pressure of the process exit and thus guaranteeing the purity of the process. These ponds operate in a range of around 344.7-413.7 KPa (50-60 psi).

The high pressure oxygen compression and accumulation means essentially comprise an oxygen piston compressor (108) and a high oxygen pressure accumulator (109). The oxygen piston compressor (108) does not use oil in its compression, which a part of the oxygen produced produces

I compress to store in the high pressure accumulator (109). The high oxygen pressure accumulator (109) stores large amounts of oxygen in a gaseous form which prevents evaporation losses. The control means of the oxygen generation system comprises a manual equipment panel (205), a PLC (206), means for receiving dissolved oxygen signals (207), a computer (208) with HMI, software (209) and control algorithms (210) and a manual valve board (211). The manual equipment panel (205) allows individual and manual operation of each of the system equipment by means of an ignition keypad. It also considers visual power indicators, emergency buttons and electric phase indicators. The PLC (206) stores the control algorithms and operates automatically constantly making decisions based on measurements of dissolved oxygen sensors and equipment status to determine whether the equipment should be turned on or off, valve etc. The reception of dissolved oxygen signals is received wirelessly, which are measured by oxygenation sensors, which in a preferred embodiment, the sensors are optical.

The computer (208) with HMI serves as an interface for the user showing in a graphic form all the relevant information on the status of the equipment, such as on or off, open or closed valves, oxygen levels in the water, oxygen flow etc. . This can modify operating parameters that influence the decision taken by the control system or rightly operate the system manually through the computer system. Having the necessary connectivity (internet), this interface can operate remotely (not needing to be on the pontoon) making it possible to operate and monitor from anywhere.

The software (209) and control algorithms (210) are stored in the PLC (206), developed exclusively for this application according to the needs and best practices established in the field. These algorithms include by way of example: PID control of dissolved oxygen levels in the cage; Smart battery charging routine; Consider equipment departure times that optimize the life of said equipment; Time frequency decision making in line with the process to be controlled and the equipment to be used; Intelligent use of the oxygen accumulation system such as using it as a buffer to optimize energy use, use it in case of mechanical emergency, use it in case of over consumption by fish biomass.

Depending on the PID controller constants assigned, the system considers the proportional error, the accumulated error and the slope of the system to determine whether or not to oxygenate a cage (3) and for how long. The system (100) then adds the amount of oxygen that needs to be delivered to the cages (3) and determines if it corresponds where to turn on one or more generation lines, that is, turn on the solenoid valve to oxygenate said particular cage (3). This decision is made for all cages (3). Subsequently, the system will determine based on how many valves will be on and for how long if: oxygenate the cages from the accumulation tanks (109), if the consumption is lower and the tanks are full; light one, two, three or all oxygen generation lines; Turn on the oxygen compressors.

The manual valve board (211) allows you to manually control the on or off of the valves that provide oxygen to the fish.

In addition, the system includes sensors such as a mass flow meter for delivered oxygen, as well as control valves for delivering oxygen to fish cages. The oxygen injection system to the cages is made by pipes that carry oxygen to fish cages and then with micro ^hoses: water being introduced at about 10 meters deep. Currently, there are oxygenation systems on the market through ceramic hoses or diffusers. The oxygenation system (100) is designed so that it can operate autonomously. Its main function is to always keep the oxygen or Set Point (SP) levels at optimal, a situation that depends on the customer who determines what is the minimum level of operation in reference to the oxygen to be supplied. In the same way, the system user is the one who monitors the system.

For the on-site generation of oxygen automatically, the process basically begins with the measurements of the oxygen sensors, which are located at strategic points within the module. These sensors can be of optical or galvanic technology that sense the level of dissolved oxygen in the water and transform it into a 4- 20 mA signal that is delivered to the system of the present invention by means of a wireless or cable signal. For example, if the SP levels were programmed at 7 PPM (parts per million), it means that any larger measurement of the oxygen sensor keeps the system off as could be a case of 7.5 PPM (in this case it is not necessary to inject oxygen), otherwise, if the measurement of the oxygen sensor is low than that specified in the SP, then the oxygenation system should be turned on, an example would be if the sensor measured 6.5 PPM.

The signals emitted by the oxygen sensors are received by the PLC (206) of the oxygenation system of the present invention and it verifies that there is a value lower than the SP to start switching on the equipment sequentially, starting with the group ignition generator (101), then the ignition of air dryers (103), then the ignition of the air compressors (102), then the ignition of the oxygen generator (106) and finally, as long as there is capacity in the ponds of accumulation (109), the ignition of the high pressure accumulator for oxygen (109), to fill or refill said accumulation tanks (109).

Once all equipment is turned on, the oxygen produced can be sent to the accumulation ponds (109) or you can directly take a feed matrix to the cages. In the feeding matrix (supplied by the accumulation ponds (109) and the production of O2 in situ), there is a totalizer, in charge of recording the oxygen consumption that is being delivered to the cages (3). Each feed matrix (4) is controlled by means of a selenoid valve, which, when switched on, allows oxygen to pass when the levels are below the SP and it operates controlled by means of the PLC (206). This equipment is able to discriminate, based on the measurements of the sensors, to which cage (3), which forms a module, feeds with oxygen independently from the cage module (2) to which it belongs.

Then the oxygen that is transported by means of the feeding matrix (4) is connected to the cage module (2) by means of a distribution box (5), which derives the oxygen to the cages (3) by means of distribution lines to finally deliver it through microperforated hoses.

Once the oxygen passes through the solenoid valve, it is directed to the cage (3) in question, by means of high-pressure hoses, which make up the feed matrix (4), upon reaching the cages (3), the oxygen It can be supplied to the water by means of different forms, among them we can find oxygenation by means of ceramic diffusers or microperforated hoses. At this point the oxygen comes out by means of very small and uniform bubbles, which guarantees a highly efficient oxygenation, this allows the levels to be raised in a case of 6.5 to 7 PPM and by measuring the sensor the measurement of the temperature is taken again. so that the PLC (206) makes the decision, in this way the process begins again. The system stays on until it reaches the SP level.

The system (100) of the present invention is designed so that it is always filling or refilling the high pressure oxygen storage tanks (109), so that when the system detects the lack of oxygen in one or more cages, First it does is use the oxygen from the accumulation ponds (109) until it reaches a certain level (it is used approximately 20% of the oxygen without turning on the equipment), or it uses the constant of the PID controller when there is some difference in the types of errors or times, on the other hand that oxygen is also used to solve any eventuality with the levels of Low oxygen, that is to say it can be used in parallel to the production of oxygen or it can be kept in reserves and used manually without the need to turn on the equipment.

Additionally, the system is designed so that it operates to power the UPS (203) and in this way the system power is maintained constantly, that is, it is designed to start only the generator in the event that the OD levels are over the SP so that sufficient energy is always maintained to energize the equipment and components. It also has the feature of operating remotely. In addition, the system is designed so that every certain amount of hours is turned on to recharge the batteries of the UPS (203), the battery charge! It does not take more than 2 hours and allows the system (100) to be energized for at least 17 hours.

Claims

1. Portable system for the generation of oxygen in situ and oxygen injection at industrial levels for fish cages in the sea, comprising a floating platform, pontoon type, with a buoyancy of at least 50 tons and is capable of being towed in Open sea, where inside it has this system that generates oxygen at 93 - 95% purity, and comprises a generator and electricity distribution system, which provides electrical energy to the components of this oxygen generating system, where the latter It basically comprises pressurized air generating means, pressurized oxygen generating means, high pressure oxygen compression and accumulation means and control means of the oxygen generation system.

2. The portable system of claim 1, wherein the electricity generating and distributing system comprises fuel accumulating means, preferably diesel, from storage ponds located inside the pontoon that allows the operation of the oxygen generation and injection system in situ for extended periods of time.

3. The portable system of claim 1, wherein the pressurized air generating means essentially comprises compressing means, which in a preferred embodiment is a reciprocating compressor that generates an air flow at a pressure of about 620.5-792 , 9 KPa (90-115 psi); drying means, which by cooling extract the water that may come in the compressed air; filter media, which in a preferred embodiment, comprise 2 filters and a centrifugal trap that remove the particles in suspension, the drops of oil that can be dragged from the compressor and finally the drops of water that leave the compressor as a complement to the action of the dryer; and air accumulating means that serve to act as a buffer of the pressure fluctuations that occur, since the oxygen generation process has an air consumption that is not stable over time. The portable system of claim 1, wherein the pressure oxygen generating means essentially comprise a system called "Pressure Swing Adsorption Generator", which takes air under pressure and passes it to a molecular sieve bed containing a specific adsorbent for the nitrogen, so that at the exit of said bed there is an enriched flow of oxygen at 93-95%, and a low pressure oxygen accumulator.

The portable system of claim 1, wherein the high pressure oxygen compression and accumulation means essentially comprise an oxygen piston compressor and a high oxygen pressure accumulator that stores large amounts of oxygen in gaseous form which prevents losses by evaporation.

The portable system of claim 1, wherein the means for controlling the oxygen generation system comprises a manual equipment panel, a PLC, means for receiving dissolved oxygen signals, a computer with HMI, a computer program with control algorithms and a manual valve board.