An automatically controllable aluminum-water reaction continuous hydrogen production and product collection system

Abstract

The application discloses an automatic controllable aluminum-water reaction continuous hydrogen production and product collection system, which mainly comprises a reaction liquid real-time preparation system, an aluminum-water reaction system, a waste liquid collection device and related equipment thereof and the like. The application proposes a continuous automatic controllable aluminum-water reaction hydrogen production system aiming at the problems of reaction activation technology, continuous feeding, reaction start-stop, reaction rate control and product collection in the process of hydrogen production by aluminum-water reaction. The application realizes real-time preparation of reaction liquid by feeding pressure and liquid level information to an integrated controller, controls the contact of reaction liquid with aluminum fuel and timely discharge of waste liquid, optimizes the hydrogen production, collection and application process. On the basis of ensuring continuous and stable hydrogen production, the application expands the types of reaction liquid and aluminum fuel, realizes clean, safe, simple, efficient, stable and controllable aluminum-water reaction hydrogen production under low temperature and low pressure, reduces the reaction cost and promotes the further application and development of green hydrogen energy.

Description

Technical Field

[0001] This invention belongs to the field of continuous and controllable hydrogen production technology of aluminum-water reaction, and specifically relates to an automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction. Background Technology

[0002] With increasingly severe environmental problems, the proportion of renewable energy consumption in global energy consumption is increasing year by year. Hydrogen energy, due to its advantages such as being clean and carbon-free and having a high calorific value, is considered one of the clean energy sources that can meet the needs of sustainable development. Currently, the main methods for hydrogen production include hydrogen production from fossil fuels, biomass, and water electrolysis. However, these methods also suffer from problems such as low efficiency, high cost, and pollution during the production process. Furthermore, the storage and transportation of hydrogen have long constrained its further development. Research has found that aluminum is a highly promising high-calorific-value hydrogen storage carrier. In-situ hydrogen production can be achieved through the aluminum-water reaction, which is environmentally friendly and allows for the recycling of products. Metallic aluminum has high chemical reactivity and can be oxidized at room temperature to form a passivation layer, solving the storage and transportation problems. However, this also means that the aluminum-water reaction needs to be activated through appropriate methods. Currently, the aluminum-water reaction is mainly activated by adding acid and alkali solutions, preparing aluminum alloys, using additives, high-temperature reactions, and preparing ultrafine aluminum powder, thereby increasing the rate and total amount of hydrogen produced. The activation process increases the difficulty of application. Issues such as reactant addition, reaction start-up and shutdown, reaction rate and heat generation control, product collection and utilization, and reaction costs still hinder the large-scale application of aluminum fuels. Different activation methods also face corresponding difficulties. Adding acid or alkali solutions, preparing aluminum alloys, and additives limit the reaction temperature, increasing the difficulty of maintaining reaction activity. High-temperature reactions and the use of ultrafine aluminum powder have limited scope, requiring special attention to application safety. In response to the common and individual difficulties faced by various activation methods, current technologies focus on different activation methods and their coupled utilization for different application scenarios. In hydrogen production applications, the focus is mainly on solving problems related to material input, product removal, and reaction rate control, developing lightweight, intensive, automated, continuous, stable, and safe aluminum-water reactors and systems to achieve clean, efficient, and green hydrogen production. Summary of the Invention

[0003] The purpose of this invention is to provide an automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction. Based on sensor monitoring of pressure and liquid level changes during the reaction process, it integrates intelligent control of the contact between aluminum and the reaction liquid in the aluminum fuel reactor, thereby controlling the reaction start-up, reaction rate, and reaction termination. By controlling the rise and fall of multiple aluminum fuel reactors and the real-time production of the reaction liquid, it achieves continuous and stable hydrogen production during the feeding process. Taking advantage of the fact that the aluminum-water reaction is an exothermic reaction, the heat of reaction is continuously generated and maintained in the initial heating system, eliminating the need for continuous heating.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] An automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction includes an integrated controller, a water tank, a catalyst tank, a reaction liquid tank, a reaction liquid flow controller, an aluminum-water reactor, a level gauge, an aluminum fuel reactor, a hydrogen storage device or fuel cell, and a hydrogen pipeline.

[0006] The aluminum-water reactor is sealed and contains a reaction liquid. A level gauge on the side wall monitors the reaction liquid level in real time and sends feedback to an integrated controller. The reaction liquid inlet connects to a water tank and a catalyst tank, while the reaction liquid outlet connects to the side wall of the aluminum-water reactor near the bottom and extends above the reaction liquid surface via an inlet pipe. A reaction liquid flow controller is installed on the inlet pipe. Several aluminum fuel reactors are connected above the aluminum-water reactor. The height of the aluminum fuel reactors is controlled by the integrated controller, allowing different aluminum fuel reactors to participate in the aluminum-water reaction at intervals. A hydrogen pipeline connects to a hydrogen storage device or fuel cell above the side wall of the aluminum-water reactor, and the hydrogen pipeline is equipped with a hydrogen switch, a hydrogen pressure detection device, a hydrogen separation and drying device, and a hydrogen flow controller. A waste liquid outlet is located at the bottom of the aluminum-water reactor.

[0007] The integrated controller connects to and controls the water tank, catalyst tank, reaction liquid tank, reaction liquid flow controller, level gauge, aluminum fuel reactor, hydrogen switch, hydrogen pressure detection device, and hydrogen flow controller via data transmission lines.

[0008] A further improvement of the present invention is that a reaction liquid switch and a reaction liquid check valve are also arranged on the liquid inlet pipeline, and the integrated controller is connected to and controls the reaction liquid switch through a data transmission line.

[0009] A further improvement of the present invention is that each aluminum fuel reactor includes an aluminum reaction vessel, an aluminum feeding pipeline, an electric actuator, an aluminum valve, and an aluminum silo; aluminum fuel is placed in the aluminum silo; the aluminum silo is connected to the aluminum reaction vessel through the aluminum feeding pipeline and the electric actuator installed on the aluminum feeding pipeline.

[0010] A further improvement of the present invention is that the aluminum fuel reactor also includes an aluminum valve disposed on the aluminum feeding pipeline.

[0011] A further improvement of the present invention is that the aluminum reaction vessel is provided with multiple water inlet holes, the diameter of which is smaller than the minimum diameter of the aluminum fuel in the aluminum silo, to prevent the aluminum fuel from leaking uncontrollably into the aluminum-water reactor.

[0012] A further improvement of this invention is that, when the n aluminum fuel reactors are working, the pressure changes generated by the system's aluminum-water reaction to produce hydrogen are fed back to the integrated controller. The height of the aluminum fuel reactor is adjusted by an electric push rod to control the contact between the fuel aluminum and the reaction liquid, thereby controlling the aluminum-water reaction and achieving continuous, stable and controllable hydrogen production.

[0013] A further improvement of the present invention is that a hydrogen check valve and a hydrogen back pressure valve are also provided on the hydrogen pipeline.

[0014] A further improvement of the present invention is that the waste liquid outlet at the bottom of the aluminum-water reactor is connected to the waste liquid tank through a waste liquid pipeline. A drain valve and a waste liquid flow controller are installed on the waste liquid pipeline. An integrated controller is connected to and controls the drain valve and the waste liquid flow controller through a data transmission line.

[0015] A further improvement of the present invention is that the reaction liquid tank is equipped with a stirring device to fully mix the water from the water tank and the catalyst from the catalyst tank. When the system is running, the reaction liquid is produced in real time in the reaction liquid tank to ensure that the reaction liquid is always in a highly active state. The catalyst is an alkaline powder or granules of sodium hydroxide, potassium hydroxide and aluminum hydroxide, and the mass concentration of the reaction liquid exceeds 10%.

[0016] A further improvement of the present invention is that, when the reaction solution is in a highly active state, the aluminum fuel is selected from aluminum alloys or micro / nano aluminum powders, or from granular aluminum blocks, aluminum ingots, aluminum sheets, and recycled waste aluminum materials.

[0017] The automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction provided by this invention has the following advantages:

[0018] 1. The level gauge and pressure detection device monitor the liquid level and hydrogen production in the aluminum-water reactor, and feed the feedback to the integrated controller to adjust the reaction liquid switch, drain valve and electric push rod and other adjustment systems. The reaction start, reaction rate and reaction termination can be controlled with one button. The adjustment process is continuous and does not affect hydrogen production.

[0019] 2. The electric actuator controls the contact between aluminum fuel and reaction liquid in the aluminum reaction vessel to achieve rapid start and stop of the reaction, and controls the reaction rate according to the contact volume between aluminum and reaction liquid.

[0020] 3. By controlling the position and height of multiple aluminum fuel reaction tanks, the addition of aluminum fuel, and the preparation of reaction liquid, continuous and stable hydrogen production is achieved. The feeding process is continuous and does not affect the total rate of hydrogen production.

[0021] 4. Taking advantage of the fact that the aluminum-water reaction is an exothermic reaction, the aluminum-water reactor is heated before the reaction starts. The subsequent reaction continuously generates heat, which increases and maintains the reaction temperature, eliminating the need for repeated heating.

[0022] 5. Use an excess of highly reactive reaction liquid, such as an alkaline solution with a mass concentration exceeding 10%, to expand the range of aluminum fuels that can be selected while ensuring efficient reaction. Aluminum alloys, micro / nano aluminum powders, aluminum blocks, aluminum ingots, aluminum sheets, and screened waste aluminum materials can be used.

[0023] 6. The aluminum fuel reactor and aluminum reaction vessel are detachable, facilitating cleaning and refueling. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an automated and controllable continuous hydrogen production and product collection system based on the aluminum-water reaction of the present invention.

[0025] Figure 2 This is a schematic diagram of an aluminum reaction vessel in an automated and controllable continuous hydrogen production and product collection system based on an aluminum-water reaction according to the present invention.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1 is the integrated controller, 2 is the data transmission line, 3 is the water tank, 4 is the catalyst tank, 5 is the reaction liquid tank, 6 is the reaction liquid switch, 7 is the reaction liquid flow controller, 8 is the reaction liquid check valve, 9 is the liquid inlet pipe, 10 is the aluminum-water reactor, 11 is the level gauge, 12 is the aluminum reaction tank, 13 is the aluminum feeding pipe, 14 is the aluminum fuel reactor, 15 is the electric actuator, 16 is the aluminum valve, 17 is the aluminum silo, 18 is the hydrogen switch, 19 is the hydrogen pressure detection device, 20 is the hydrogen check valve, 21 is the hydrogen back pressure valve, 22 is the hydrogen separation and drying device, 23 is the hydrogen flow controller, 24 is the hydrogen storage device or fuel cell, 25 is the drain valve, 26 is the waste liquid pipe, 27 is the waste liquid flow controller, 28 is the waste liquid tank, 29 is the reaction liquid, 30 is the reaction liquid level, 31 is the hydrogen pipe, 32 is the water inlet, and 33 is the aluminum fuel. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings:

[0029] See Figure 1This invention provides an automated and controllable continuous hydrogen production and product collection system for an aluminum-water reaction, comprising an integrated controller 1, a data transmission line 2, a water tank 3, a catalyst tank 4, a reaction liquid tank 5, a reaction liquid switch 6, a reaction liquid flow controller 7, a reaction liquid check valve 8, an inlet pipe 9, an aluminum-water reactor 10, a level gauge 11, an aluminum reaction tank 12, an aluminum feeding pipe 13, an aluminum fuel reactor 14, an electric actuator 15, an aluminum valve 16, an aluminum silo 17, a hydrogen switch 18, a hydrogen pressure detection device 19, a hydrogen check valve 20, a hydrogen back pressure valve 21, a hydrogen separation and drying device 22, a hydrogen flow controller 23, a hydrogen storage device or fuel cell 24, a drain valve 25, a waste liquid pipe 26, a waste liquid flow controller 27, a waste liquid tank 28, a reaction liquid 29, a reaction liquid level 30, a hydrogen pipe 31, a water inlet 32, and aluminum fuel 33.

[0030] The reaction liquid tank 5 is connected to the water tank 3 and the catalyst tank 4 via an inlet pipe 9. The reaction liquid tank 5 is connected to the side wall of the aluminum-water reactor 10, extending near the bottom to above the reaction liquid surface 30. A reaction liquid switch 6, a reaction liquid flow controller 7, and a reaction liquid check valve 8 are sequentially arranged on the inlet pipe 9. The aluminum-water reactor 10 is in a sealed state, and all connections to its components are reinforced with sealing gaskets. The aluminum-water reactor 10 can withstand a positive pressure range higher than the maximum pressure required for stable hydrogen production. A level gauge 11 is installed on the side wall of the aluminum-water reactor 10 to monitor the reaction liquid surface 30 in real time and provide feedback to the integrated controller 1. n aluminum fuel reactors 14 are connected above the aluminum-water reactor 10. The reactor 14 consists of an aluminum reaction tank 12, an aluminum feeding pipeline 13, an electric push rod 15, an aluminum valve 16, and an aluminum silo 17; aluminum fuel 33 is placed in the aluminum silo 17; the aluminum fuel reactor 14 is controlled by an integrated controller 1 to raise and lower its height; the upper side wall of the aluminum-water reactor 10 is connected to a hydrogen storage device or a fuel cell 24 via a hydrogen pipeline 31, and the hydrogen pipeline 31 is sequentially equipped with a hydrogen switch 18, a hydrogen pressure detection device 19, a hydrogen check valve 20, a hydrogen back pressure valve 21, a hydrogen separation and drying device 22, and a hydrogen flow controller 23; the bottom of the aluminum-water reactor 10 is equipped with a waste liquid pipeline 26 connected to a waste liquid tank 28, and the waste liquid pipeline 26 is equipped with a drain valve 25 and a waste liquid flow controller 27.

[0031] The integrated controller 1 is connected to and controls the water tank 3, catalyst tank 4, reaction liquid tank 5, reaction liquid switch 6, reaction liquid flow controller 7, liquid level gauge 11, aluminum fuel reactor 14, hydrogen switch 18, hydrogen pressure detection device 19, hydrogen flow controller 23, drain valve 25 and waste liquid flow controller 27 via data transmission line 2.

[0032] The specific working process of this invention is as follows:

[0033] 1) Taking an aluminum fuel reactor 14 with a quantity n of 4 as an example, close all aluminum gate valves 16 and drain valves 25. Thoroughly mix water from water tank 3 and catalyst from catalyst tank 4 in reaction liquid tank 5. Open reaction liquid switch 6 and hydrogen switch 18 to allow a certain amount of reaction liquid 29 to enter aluminum-water reactor 10, reaching reaction liquid level 30 and heating to a specified temperature. Close reaction liquid switch 6, and all aluminum fuel reactors 14 remain above reaction liquid level 30. 2) Keeping reaction liquid switch 6 and hydrogen switch 18 open, open all aluminum valves 16 to allow a certain amount of aluminum fuel 33 from aluminum silo 17 to enter aluminum reaction tank 12 through aluminum feed pipe 13. At this time, aluminum fuel reactors 14 still remain above reaction liquid level 30. Then, the integrated controller 1 controls the designated electric push rod 15 to move the aluminum fuel reactors (numbered 1 and 3)... (For example) The aluminum fuel 33 falls sequentially to a designated height below the reaction liquid surface 30, and the aluminum-water reaction 29 comes into contact with it, thus initiating the aluminum-water reaction; 3) After the reaction starts, hydrogen is gradually produced, and the pressure inside the aluminum-water reactor 10 gradually increases. When the amount of hydrogen produced reaches a certain level, the pressure reaches the set value of the hydrogen pressure detection device 19, and the hydrogen passes sequentially through the hydrogen check valve 20, the hydrogen back pressure valve 21, the hydrogen separation and drying device 22, and the hydrogen flow controller 23 before entering the hydrogen storage device or fuel cell 24. The system begins to stably produce and output hydrogen; 4) Aluminum reacts with the reaction liquid 29. Taking an alkaline solution as an example, after the reaction, it will dissolve in an excess of alkaline solution. As the aluminum-water reaction proceeds, the amount of hydrogen produced gradually decreases, and the pressure inside the aluminum-water reactor 10 gradually decreases. When the pressure decreases to the set value of the hydrogen pressure detection device 19, The integrated controller 1 controls the designated electric push rod 15 to lower the aluminum fuel reactors 14 (No. 2 and No. 4) sequentially to a designated height below the reaction liquid level 30, while simultaneously raising the aluminum fuel reactors 14 (No. 1 and No. 3) to above the reaction liquid level 30. The aluminum valves 16 of aluminum fuel reactors 14 (No. 1 and No. 3) are reopened, and a certain amount of aluminum fuel 33 in the aluminum silo 17 is reintroduced into the aluminum reaction tank 12 through the aluminum feeding pipeline 13 for subsequent reaction. In this way, the integrated controller 1 operates in a cycle according to the result of the hydrogen pressure detection device 19 via the data transmission line 2. 5) As the aluminum-water reaction proceeds, the reaction liquid level 30 and the concentration of the reaction liquid 29 gradually decrease. When the reaction liquid level 30 drops to the set value of the level gauge 11, the water from the water tank 3 and the catalyst from the catalyst tank 4 are thoroughly mixed again in the reaction liquid tank 5, the reaction liquid 29 is prepared, and the reaction liquid switch 6 is opened until the liquid level rises back to the reaction liquid level 30, after which the drain valve 25 is opened. At this time, the reaction liquid switch 6 remains open. The reaction liquid 29 is updated by using different set flow rates for the reaction liquid flow controller 7 and the waste liquid flow controller 27 without affecting the generation of hydrogen gas in the aluminum-water reaction, ensuring that the reaction liquid 29 always maintains a sufficient quantity and high concentration. The discharged waste liquid is temporarily stored in the waste liquid tank 28 through the waste liquid pipeline 26 and will be recycled later.6) When the hydrogen storage tank and fuel cell 4 no longer require hydrogen supply, feedback is sent to the integrated controller 1. First, all aluminum fuel reactors 14 are raised to above the reaction liquid level 30. Then, the reaction liquid switch 6 and hydrogen switch 18 are turned off. Finally, the drain valve 25 is opened to discharge the waste liquid after reaction and the unreacted reaction liquid 29 into the waste liquid tank 28 for recycling.

[0034] The present invention provides an automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction. The working steps are as follows: (1) the reaction start-up, reaction rate and reaction termination are controlled by a sensor and an integrated controller with one click; (2) the heat released by the aluminum-water reaction is utilized to continuously heat the reaction liquid, maintain and slightly increase the reaction temperature; (3) the integrated controller is used to adjust the switches, drain valves and electric push rods to continuously feed and prepare highly active reaction liquid, and the hydrogen production is not affected during the adjustment process.

[0035] In step (1), before the system is started, the system parameters are determined based on the experimental results and then corrected based on the experimental results. Finally, the system parameters are determined, including the hydrogen flow range, reactor pressure range, liquid level height, and electric push rod displacement.

[0036] Furthermore, the number of aluminum fuel reactors in the system can be determined based on parameters such as the required hydrogen flow rate of the system.

[0037] Furthermore, the reaction solution can be selected as an acidic solution or an acidic liquid according to the specific application scenario, and the concentration of the reaction solution can be determined according to parameters such as the required hydrogen flow rate and velocity.

[0038] Furthermore, the type of aluminum fuel can be selected according to specific application conditions, such as micron-sized aluminum powder, granular aluminum blocks, aluminum ingots, and aluminum sheets.

[0039] The above content is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any simple deductions or substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the concept of the present invention, should be regarded as falling within the scope of patent protection of the present invention as determined by the submitted claims.

Claims

1. An automated and controllable continuous hydrogen production and product collection system based on an aluminum-water reaction, characterized in that, It includes an integrated controller (1), a water tank (3), a catalyst tank (4), a reaction liquid tank (5), a reaction liquid flow controller (7), an aluminum-water reactor (10), a level gauge (11), an aluminum fuel reactor (14), a hydrogen storage device or fuel cell (24), and a hydrogen pipeline (31). The aluminum-water reactor (10) is in a sealed state. A reaction liquid (29) is placed inside the aluminum-water reactor (10). A level gauge (11) is installed on the side wall to monitor the reaction liquid level (30) in real time and provide feedback to the integrated controller (1). The inlet of the reaction liquid tank (5) is connected to the water tank (3) and the catalyst tank (4). The outlet of the reaction liquid tank (5) is connected to the side wall of the aluminum-water reactor (10) near the bottom and extends above the reaction liquid level (30) via an inlet pipe (9). A reaction liquid flow controller (7) is arranged on the inlet pipe (9). A [missing information - likely a device or device] is connected above the aluminum-water reactor (10). n Aluminum fuel reactor (14); The aluminum fuel reactor (14) is controlled by an integrated controller (1) to raise and lower its height, so that different aluminum fuel reactors (14) participate in the aluminum-water reaction at intervals; The aluminum-water reactor (10) is connected to a hydrogen storage device or fuel cell (24) through a hydrogen pipeline (31) on the upper side wall, and a hydrogen switch (18), a hydrogen pressure detection device (19), a hydrogen separation and drying device (22) and a hydrogen flow controller (23) are arranged in sequence on the hydrogen pipeline (31); A waste liquid outlet is provided at the bottom of the aluminum-water reactor (10); The integrated controller (1) is connected to and controls the water tank (3), catalyst tank (4), reaction liquid tank (5), reaction liquid flow controller (7), level gauge (11), aluminum fuel reactor (14), hydrogen switch (18), hydrogen pressure detection device (19) and hydrogen flow controller (23) respectively via data transmission line (2). Each aluminum fuel reactor (14) includes an aluminum reaction vessel (12), an aluminum feed line (13), an electric push rod (15), an aluminum valve (16), and an aluminum silo (17); aluminum fuel (33) is placed in the aluminum silo (17); the aluminum silo (17) is connected to the aluminum reaction vessel (12) through the aluminum feed line (13) and the electric push rod (15) installed on the aluminum feed line (13); The aluminum fuel reactor (14) also includes an aluminum valve (16) installed on the aluminum feed line (13). The aluminum reaction vessel (12) is evenly distributed with multiple water inlet holes (32). The diameter of the water inlet holes (32) is smaller than the minimum diameter of the aluminum fuel (33) in the aluminum silo (17) to prevent the aluminum fuel (33) from leaking uncontrollably into the aluminum-water reactor (10). n When the aluminum fuel reactor (14) is working, the pressure changes generated by the system’s aluminum-water reaction to produce hydrogen are fed back to the integrated controller (1). The height of the aluminum fuel reactor (14) is adjusted by the electric push rod (15) to control the contact between the fuel aluminum and the reaction liquid (29), thereby controlling the aluminum-water reaction and achieving continuous, stable and controllable hydrogen production.

2. The automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction according to claim 1, characterized in that, A reaction liquid switch (6) and a reaction liquid check valve (8) are also arranged on the liquid inlet line (9). The integrated controller (1) is connected to and controls the reaction liquid switch (6) through the data transmission line (2).

3. The automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction according to claim 1, characterized in that, The hydrogen pipeline (31) is also equipped with a hydrogen check valve (20) and a hydrogen back pressure valve (21).

4. The automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction according to claim 1, characterized in that, The waste liquid outlet at the bottom of the aluminum-water reactor (10) is connected to the waste liquid tank (28) through the waste liquid pipeline (26). The waste liquid pipeline (26) is equipped with a drain valve (25) and a waste liquid flow controller (27). The integrated controller (1) is connected to and controls the drain valve (25) and the waste liquid flow controller (27) through the data transmission line (2).

5. The automated and controllable continuous hydrogen production and product collection system for aluminum-water reaction according to claim 1, characterized in that, The reaction liquid tank (5) is equipped with a stirring device to fully mix the water from the water tank (3) and the catalyst from the catalyst tank (4). When the system is running, the reaction liquid (29) is produced in the reaction liquid tank (5) in real time to ensure that the reaction liquid (29) is always in a high-activity state. The catalyst is an alkaline powder or granules of sodium hydroxide, potassium hydroxide and aluminum hydroxide, and the mass concentration of the reaction liquid (29) exceeds 10%.

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