Modularized geothermal fluid treatment device and method for efficient desulfurization and dechlorination

Abstract

The invention relates to the technical field of geothermal energy development, in particular to a device and method for solving the problems of corrosive substances (hydrogen sulfide and chloride ions) and scaling in shallow geothermal fluid. According to the efficient desulfurization and dechlorination modular geothermal fluid treatment device and the efficient desulfurization and dechlorination modular geothermal fluid treatment method, efficient removal of H2S and Cl <-> and recycling of by-products are achieved through a FeOOH chemical adsorption and electrolytic oxidation technology. The device adopts intelligent control and modular design, has the advantages of corrosion resistance, high temperature resistance, low energy consumption and the like, and can remarkably improve the economical efficiency and environmental friendliness of a geothermal system.

Description

Technical Field

[0001] The present invention relates to the field of geothermal energy development technology, and specifically to an efficient treatment device and method for corrosive substances (hydrogen sulfide, chloride ions) and scaling problems in shallow geothermal fluids, which is suitable for scenarios such as geothermal power generation and comprehensive utilization of hot springs. Background Art

[0002] my country boasts abundant geothermal resources and enormous potential for development and utilization. Compared to other renewable energy sources like wind and photovoltaic power, geothermal energy is unaffected by weather and seasonal variations, exhibiting greater stability and promising prospects for development and utilization. Shallow geothermal resources are abundant and widely distributed in my country, making most regions suitable for shallow geothermal development. However, technical challenges remain in shallow geothermal development, deterring investors and hindering its vigorous development.

[0003] Shallow geothermal applications mainly include power generation and the comprehensive utilization of hot springs. Since geothermal fluids are non-drinking water resources, users often ignore their chemical properties when using them. The hydrogen sulfide (H2S) and chloride ions (Cl-) commonly found in shallow geothermal fluids can cause electrochemical corrosion of metal pipes. High concentrations of chloride ions (Cl-) can destroy the passivation film on the metal surface, leading to severe pitting and crevice corrosion, especially in areas such as welds and flange connections, to which stainless steel is particularly sensitive. Hydrogen sulfide dissolved in the fluid dissolves in water to form an acidic solution, which can cause uniform or localized corrosion of pipe metals (especially iron), promote oxygen embrittlement, and shorten equipment life. At the same time, the scaling layer formed by the precipitation of minerals (such as CaCO3 and SiO2) due to temperature and pressure changes significantly reduces heat exchange efficiency and increases operation and maintenance costs.

[0004] Desulfurization and dechlorination technologies have yet to be applied to shallow geothermal fluids. Currently, these technologies primarily target industrial wastewater, using chemical agents, physical filtration, single electrolysis, and biotechnology. These technologies primarily focus on single-step desulfurization or single-step dechlorination, with no simultaneous desulfurization and dechlorination technologies being used.

[0005] Traditional technologies have the following defects:

[0006] 1. Chemical method: Continuous addition of corrosion inhibitors is required, which can easily cause secondary pollution and is costly;

[0007] 2. Physical filtration method: The filter material needs to be replaced frequently and multiple pollutants cannot be removed simultaneously;

[0008] 3. Single electrolysis method: high energy consumption and potential safety hazards due to chlorine gas leakage;

[0009] 4. Biotechnology: slow start-up and requires high adaptability of the bacterial flora.

[0010] In response to the above problems, the present invention proposes a modular desulfurization and dechlorination device, which can simultaneously achieve desulfurization and dechlorination of geothermal fluids by coupling chemical adsorption and electrochemical technology, thereby achieving efficient and coordinated removal of pollutants and resource recovery. Summary of the Invention

[0011] In response to the above problems, the present invention proposes a high-efficiency modular desulfurization and dechlorination device, which breaks the limitations of traditional technology by coupling chemical adsorption and electrochemical technology, and realizes efficient coordinated removal of pollutants and resource recovery.

[0012] The present invention adopts the following technical solutions:

[0013] A modular geothermal fluid treatment device and method for efficient desulfurization and dechlorination comprises the following steps:

[0014] The device consists of a water inlet unit, a desulfurization module, a dechlorination module, an intelligent control unit and a water outlet unit (see Figure 1 ), the core innovations are as follows:

[0015] Desulfurization module: A honeycomb porous ceramic matrix is ​​used to load nano-iron hydroxide (FeOOH) coated filter screen, and a detachable snap-on design allows for quick replacement. H2S reacts with FeOOH as follows:

[0016] 2FeOOH+3H2S→Fe2S3+4H2O

[0017] The generated Fe2S3 is oxidized and regenerated under aeration conditions:

[0018] 2Fe2S3+3O2+6H2O→4FeOOH+6S↓

[0019] Elemental sulfur can be recycled periodically to achieve resource utilization.

[0020] Chlorine removal module: A titanium-based IrO2-Ta2O5 coated chlorine anode and a nickel alloy cathode form an electrolytic cell, equipped with a gas sealing collection system. The electrolytic reaction is as follows:

[0021]

[0022] The generated chlorine gas is absorbed by alkaline solution (NaOH) to form sodium hypochlorite (NaClO), avoiding the risk of direct discharge and can be reused as a disinfectant.

[0023] Intelligent control unit: integrated pH, conductivity sensor and PLC controller, real-time adjustment of electrolysis current intensity (50-200A / m 2 ) and aeration volume to adapt to different geothermal fluid conditions (temperature: 50-120℃, Cl- concentration ≤5000mg / L).

[0024] The beneficial effects of the present invention are:

[0025] This coupled chemical adsorption and electrochemical technology is optimized to address the electrochemical corrosion of metal pipes caused by hydrogen sulfide (H2S) and chloride ions (Cl-) commonly found in shallow geothermal fluids, as well as the scaling layer formed by the precipitation of minerals due to temperature and pressure fluctuations. Ultimately, this achieves efficient and coordinated pollutant removal and resource recovery. This breaks the limitations of traditional methods, achieving efficient collaboration, low-carbon recycling, and convenient operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0027] Figure 1 A schematic diagram of the three-dimensional structure of the device, marking the connection relationship between each module and the fluid path;

[0028] Figure 2 This is a three-dimensional diagram of the desulfurization unit;

[0029] Figure 3 This is a three-dimensional diagram of the dechlorination device. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] like Figures 1 to 3 As shown, the present invention provides a technical solution: a modular geothermal fluid treatment device and method for efficient desulfurization and dechlorination, comprising the following steps:

[0032] Take a medium-temperature geothermal field (fluid temperature 90°C, H2S 200ppm, Cl- 3000mg / L) as an example:

[0033] 1. The water inlet is directly connected to the geothermal water produced by the geothermal well.

[0034] 2. The geothermal water flows through the desulfurization device, which is equipped with a detachable FeOOH filter to convert H2S into Fe2S3. The generated Fe2S3 adheres to the FeOOH filter;

[0035] 3. Regularly replace the FeOOH filter. Fe2S3 is oxidized and regenerated into S element under aeration conditions and recycled.

[0036] 3. The geothermal fluid after desulfurization treatment passes through a one-way water valve, which can ensure that the geothermal fluid can only flow out of the desulfurization device and cannot flow back into the desulfurization device;

[0037] 4. The geothermal fluid enters the dechlorination device, which is equipped with an electrolytic cell. At a current density of 150A / m 2 The lower electrolysis removes chlorine, and the generated Cl2 enters the gas collecting device through the upper exhaust hole;

[0038] 5. After Cl2 enters the gas collecting device, it reacts with NaOH solution to generate NaClO. NaClO solution is regularly released from the tap for recycling, and NaOH solution is regularly added;

[0039] 6. The geothermal fluid treated by the electrolytic cell flows out from the outlet for user use.

[0040] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A modular geothermal fluid treatment device with high efficiency desulfurization and dechlorination, characterized by: It includes a desulfurization module, a dechlorination module and an intelligent control unit. The desulfurization module adopts a detachable FeOOH coated filter. The dechlorination module includes a titanium-based IrO2-Ta2O5 anode and a gas sealing system.

2. The device according to claim 1, characterized in that: The FeOOH coating is loaded on the porous ceramic substrate by the sol-gel method, and the specific surface area is ≥150m 2 / g.

3. The device according to claim 1, characterized in that: The electrolytic cell is equipped with an alkali solution absorption tower, and the Cl2 conversion efficiency is ≥95%.

4. A high-efficiency desulfurization and dechlorination method, characterized in that: The process includes hydrogen sulfide chemical adsorption, sulfur resource recovery, chloride ion electrolytic conversion, sodium hypochlorite recovery, and intelligent dynamic control. The process includes the following steps: The geothermal fluid enters the desulfurization device, and the H2S in the geothermal fluid is converted into Fe2S3. The Fe2S3 is oxidized and regenerated into recyclable sulfur through aeration. The geothermal fluid after desulfurization treatment enters the dechlorination device, and after electrolysis, it generates Cl2 and enters the gas collection device; After Cl2 enters the gas collecting device, it reacts with NaOH solution to generate NaClO which can be recycled; The desulfurized and dechlorinated geothermal fluid flows out from the outlet for use by users.

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