Demisting system for reducing concentration of SO4 < 2-> in flue gas and SO2 production system
By adopting a two-stage tandem device and a secondary fog network in the sulfur dioxide production system, the concentration of SO42- in flue gas has been successfully reduced, solving the problem of failure and pipeline blockage of absorption liquid, improvement of production efficiency and cost control. Essence
Patent Information
- Application Number
- CN202322836624.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-23
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2033-10-23
AI Technical Summary
During the sulfur dioxide production process of existing devices, the SO42-concentration in the flue gas is difficult to effectively reduce, resulting in failure of the absorbent liquid and blockage of the pipeline, affecting production efficiency and cost control.
Use at least two -stage series of degradation device, including dehuminum tower, fiber dehomators, acid tanks, and voltic acid pipes, combined with secondary fog nets, forming secondary foaming to further remove the acid mist and the acid mist and So42-.
A significant reduction of the concentration of SO42- in flue gas, reducing the brought in of sulfate root ions, extending the service life of sodium citrate, improving the absorption efficiency of sulfur dioxide and reducing production costs.
Smart Images
Figure CN222384498U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of sulfur dioxide production, and specifically relates to a method for reducing SO4 2 Concentration demisting system and SO2 production system. Background Art
[0002] The core technology of preparing liquid sulfur dioxide by sodium citrate method is the absorption and decomposition of sulfur dioxide. When sulfur dioxide is dissolved in water, it will form medium-strong acid H2SO3 and further dissociate into HSO3 - and H + As the dissolution continues, H + The increase in concentration will cause the pH of the solution to decrease, which in turn inhibits the continued dissolution of sulfur dioxide. When sodium citrate is added to water, it will react with H + A multi-stage buffer is formed, and the citrate ions in the solution can react with H + Binding inhibition H + The concentration continues to rise, keeping the solution pH within a stable range, thus ensuring the normal absorption of sulfur dioxide. The optimum pH of the absorption solution can be determined based on the sulfur dioxide concentration in the gas. The reaction process of sulfur dioxide absorption is as follows:
[0003]
[0004] The overall reaction equation can be expressed as:
[0005]
[0006] Where: C i t represents citric acid, C i t 3- It stands for citrate.
[0007] The solution that has absorbed sulfur dioxide is sent to the desorption tower and released by heating. This process is the desorption of sulfur dioxide. As can be seen from the above formula, desorption is the reverse process of the absorption process. The solution can be recycled after treatment.
[0008] The main process flow of preparing sulfur dioxide by sodium citrate method is: purification, absorption, desorption, cooling and drying, compression and liquefaction. Specifically, the high-temperature furnace gas (SO2, SO3, air, etc.) delivered by the sulfuric acid system is cooled and then enters the pickling tower and demister in turn to remove most of the SO3, acid mist and water impurities. The purified furnace gas is sent to the absorption tower from the bottom and contacts with the citric acid-sodium citrate buffer from the lean liquid tank in reverse, absorbing and transferring most of the sulfur dioxide gas into the solution to form a rich liquid, and the tail gas is purified and discharged. The rich liquid is collected and cooled and then sent to the desorption tower. The hot air flow heated by the heating kettle contacts in the tower to continuously increase the temperature of the solution, release sulfur dioxide from the rich liquid, escape from the top of the analysis tower, and is compressed to form liquid sulfur dioxide after cooling and drying. The solution flowing out from the bottom enters the heating kettle for further heating, so that the residual sulfur dioxide in the solution continues to be released. The released sulfur dioxide gas mixed with water vapor enters the desorption tower through the top of the heating kettle to conduct heat and mass transfer with the rich liquid, and the solution at the bottom of the heating kettle becomes the lean liquid. The lean liquid enters the lean-rich liquid heat exchanger to transfer part of the heat to the rich liquid, and then is sent to the lean liquid cooler for cooling and then pumped into the lean liquid tank. The solution in the tank is crystallized and filtered and then returned through the underground tank for use as absorption liquid.
[0009] In the process of producing sulfur dioxide by the citric acid-sodium citrate method, due to the recycling of the solution, in production, although there is a pre-purification process that can remove most impurities, the tail gas from the acid system may contain some acid mist and SO3 gas when passing through the purification system. It cannot be effectively removed and will generate SO4 after entering the absorption liquid. 2- In addition, due to the presence of oxygen, there will still be side reactions in the solution during the absorption process: 2HSO3 - +O2→2H++2SO4 2- This reaction also results in SO4 2- The generation of SO4 2- When the solution contains SO4 2- When the concentration reaches a certain level, the generation rate will be greatly increased, which will not only lead to the failure of the absorption liquid, but also cause sulfate to combine with sodium ions to produce sodium sulfate crystals. In severe cases, it will also cause pipeline blockage and accelerate various side reactions, which is extremely unfavorable to production. Therefore, in order to reduce the impact of sulfate on production, the most important thing in process control is to reduce SO4 in the process system. 2- The production performance is that the consumption of citric acid is reduced. In terms of cost control, in addition to the fixed costs such as equipment and manpower required for process and production, the largest cost comes from the consumption of production auxiliary materials. In this process, the most important auxiliary material with the highest unit cost is citric acid.
[0010] Generally speaking, the most direct way to reduce the consumption of citric acid is to strictly control the composition of the absorption liquid. When the furnace gas enters the sulfur dioxide production system, various means and measures are used to ensure that the content of each component is within the control range of the process indicators to ensure the stability of the sulfur dioxide absorption efficiency. Generally, regular monitoring and analysis are performed to observe the changes and fluctuations of key components in the solution, and the composition of the solution is adjusted in real time according to the actual situation to reduce SO4 2- concentration. Because of the large amount of SO4 2- Compounds Na2SO4 and NaHSO4 will be formed in the solution. These two substances will precipitate from the solution in the form of crystals after accumulation. This result will not only lead to blockage of pipelines and equipment, but also cause a serious decrease in the absorption efficiency of sulfur dioxide when passing through the absorption liquid and a large consumption of citric acid absorption liquid.
[0011] To prevent the loss of citric acid in the absorption liquid, the main method is to reduce SO4 2- There are usually two ways to reduce the impact of SO3 gas and acid mist in the absorption tower: one is to purify the furnace gas, and make the concentration of SO3 gas and acid mist entering the absorption tower as low as possible after acid washing and demisting; the other is to reduce the SO4 2- To separate.
[0012] The problem with the existing device in actual production is that due to the irrationality of the design, the flue gas from sulfuric acid production may still contain some acid mist after acid washing and demisting, which cannot be effectively captured and enters the absorption liquid to generate SO4 2- , the purification effect is difficult to meet production needs. Utility Model Content
[0013] In view of the problems existing in the prior art, the utility model provides a method for reducing SO4 2- The concentration demisting system and SO2 production system specifically include the following:
[0014] A method for reducing SO4 in flue gas 2- The invention discloses a demisting system for reducing concentration, comprising at least two stages of demisting devices connected in series, wherein the demisting device comprises a demisting tower, a demisting device arranged in the middle section of the demisting tower, an acid collecting tank arranged in the demisting tower, and an acid delivery pipeline; a smoke inlet and a reserved opening are arranged at the lower end of the demisting tower, and a smoke outlet is arranged at the upper end of the demisting tower; a liquid collection outlet is arranged at the bottom end of the demisting device; the acid collecting tank is arranged below the demisting device, and the acid collecting tank is provided with a liquid inlet and a liquid outlet, and the liquid inlet of the acid collecting tank is connected with the liquid collection outlet of the demisting device; one end of the acid delivery pipeline is arranged outside the demisting tower, and the other end passes through the reserved opening of the demisting tower and is connected with the liquid outlet of the acid collecting tank, and an acid discharge valve is also arranged on the acid delivery pipeline; the smoke inlet of the latter stage demisting tower is connected with the smoke outlet of the former stage demisting tower.
[0015] Preferably, the demister is a fiber demister, which includes a bottom liquid receiving tray, a top cover, and a fiber demister side wall disposed between the bottom liquid receiving tray and the top cover, and a liquid collecting outlet is disposed on the bottom liquid receiving tray. The demisting principle of the fiber demister is to allow the smoke to pass through the fiber demister side wall, and to capture the mist particles on a single fiber through inertial collision, direct interception, and the principle of Brownian motion, and gradually condense into large particles or liquid films, and under the action of the driving force of the airflow, flow along the inner surface of the fiber demister side wall under the action of gravity to the bottom liquid receiving tray, and then flow out from the liquid collecting outlet on the bottom liquid receiving tray, so as to capture the mist liquid and purify the gas.
[0016] Preferably, it also includes a secondary demisting net, which is tilted in the demisting tower and located above the demister. The secondary demisting net is tilted, so the acid liquid condensed on it can flow along the tilted demisting net to the wall of the demisting tower under the action of gravity, and then flow along the wall of the demisting tower to the bottom of the demister, and then flow into the acid collecting tank from the liquid collecting outlet of the demister. The function of the secondary demisting net is secondary demisting, which further enhances the SO4 2- removal effect.
[0017] Preferably, the secondary demisting net is provided with demisting fibers, and the demisting principle of the secondary demisting net is the same as that of the fiber demister.
[0018] Preferably, the demisting system for reducing the sulfate ion concentration in the flue gas comprises two stages of demisting devices connected in series.
[0019] A method for reducing SO4 in flue gas 2- Concentration of mist removal system in SO2 production system.
[0020] Beneficial effects of the utility model:
[0021] (1) The utility model discloses a method for reducing SO4 in flue gas 2- The concentration demisting system improves the furnace gas purification effect by modifying the existing purification and demisting device. It is equipped with at least two stages of demisting devices in series to form secondary defoaming to eliminate as much acid foam as possible from the high-temperature furnace gas of the sulfuric acid system. The acid mist entrained in the furnace gas entering the citric acid absorption liquid is greatly reduced, which reduces the introduction of sulfate ions from the source and prolongs the service life of sodium citrate.
[0022] (2) The utility model discloses a method for reducing SO4 in flue gas 2-The demisting system for the concentration also includes a secondary demisting net, which is tilted in the demisting tower and located above the demister. The secondary demisting net is tilted, so the condensed acid liquid on it can flow along the tilted demisting net to the wall of the demisting tower under the action of gravity, and then flow along the wall of the demisting tower to the bottom of the demister, and then flow into the acid collecting tank from the liquid collecting outlet of the demister. The function of the secondary demisting net is secondary demisting, which further enhances the SO4 2- removal effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 The utility model discloses a method for reducing SO4 in flue gas. 2- Schematic diagram of the structure of the demisting system of concentration;
[0024] Figure 2 The utility model discloses a method for reducing SO4 in flue gas. 2- Schematic diagram of the structure of the demisting system of concentration;
[0025] Figure 3 The utility model discloses a process flow diagram of the SO2 production system. DETAILED DESCRIPTION
[0026] The utility model is described in detail below in conjunction with the accompanying drawings and specific implementation methods. The embodiments shown below do not limit the contents of the utility model described in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary as solutions of the utility model described in the claims.
[0027] Reference Figure 1-3 The arrows in the figure indicate the gas flow direction. 2- The demisting system for reducing the concentration of SO4 in flue gas comprises at least two stages of demisting devices connected in series, the demisting device comprises a demisting tower 1, a demisting device 2 arranged in the middle section of the demisting tower 1, an acid collecting tank 3 arranged in the demisting tower 1, and an acid delivery pipeline; the lower end of the demisting tower 1 is provided with a flue gas inlet and a reserved port, and the upper end of the demisting tower 1 is provided with a flue gas outlet; the bottom end of the demisting device 2 is provided with a liquid collection outlet; the acid collecting tank 3 is arranged below the demisting device 2, the acid collecting tank 3 is provided with a liquid inlet and a liquid outlet, and the liquid inlet of the acid collecting tank 3 is connected to the liquid collection outlet of the demisting device 2; one end of the acid delivery pipeline is arranged outside the demisting tower 1, and the other end passes through the reserved port of the demisting tower 1 and is connected to the liquid outlet of the acid collecting tank 3, and an acid discharge valve is also provided on the acid delivery pipeline; the flue gas inlet of the latter stage demisting tower 1 is connected to the flue gas outlet of the former stage demisting tower 1. The utility model discloses a method for reducing SO4 in flue gas. 2-The concentration demisting system improves the furnace gas purification effect by modifying the existing purification and demisting device. It is equipped with at least two stages of demisting devices in series to form secondary defoaming to eliminate as much acid foam as possible from the high-temperature furnace gas of the sulfuric acid system. The acid mist entrained in the furnace gas entering the citric acid absorption liquid is greatly reduced, which reduces the introduction of sulfate ions from the source and prolongs the service life of sodium citrate.
[0028] In one embodiment of the present invention, the demister 2 is a fiber demister, and the fiber demister 2 includes a bottom liquid receiving tray 4, a top cover 6, and a fiber demister side wall ( Figure 1 In order to show it clearly, the fiber demister side wall is processed with perspective, and it is actually a complete cylindrical side wall. The bottom liquid collecting tray 4 is provided with a liquid collecting outlet. The demisting principle of the fiber demister 2 is to make the smoke pass through the fiber demister side wall, and capture the mist particles on a single fiber through inertial collision, direct interception, and the principle of Brownian motion, and gradually condense into large particles or liquid film. Under the driving force of the airflow, it flows to the bottom liquid collecting tray 4 along the inner surface of the fiber demister side wall under the action of gravity, and then flows out from the liquid collecting outlet on the bottom liquid collecting tray 4, so as to capture the mist liquid and purify the gas.
[0029] Reference Figure 2 , the arrow in the figure indicates the gas flow direction. In one embodiment of the utility model, it also includes a secondary demisting net 7, which is tilted in the demisting tower 1 and located above the demister 2. The secondary demisting net 7 is tilted, so the acid liquid condensed on it can flow along the tilted demisting net to the wall of the demisting tower 1 under the action of gravity, and then flow along the wall of the demisting tower 1 to the bottom of the demister 2, and then flow from the liquid collecting outlet of the demister 2 into the acid collecting tank 3. The function of the secondary demisting net 7 is secondary demisting, which further enhances the SO4 2- removal effect.
[0030] In one embodiment of the present invention, demisting fibers are arranged on the secondary demisting net 7 , and the demisting principle of the secondary demisting net 7 is the same as that of the fiber demister 2 .
[0031] In one embodiment of the utility model, the demisting system for reducing the sulfate ion concentration in the flue gas comprises two stages of demisting devices connected in series.
[0032] Reference Figure 3 , a method for reducing SO4 in flue gas 2- Concentration of mist removal system in SO2 production system.
[0033] In the description of the present application, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.
[0034] Unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0035] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for reducing SO4 in flue gas 2- concentration demisting system, characterized in that, The invention comprises a defogger device of at least two stages connected in series, the defogger device comprises a defogger tower, a defogger arranged in the middle section of the defogger tower, an acid collecting tank arranged in the defogger tower, and an acid transport pipeline; a smoke inlet and a reserved opening are arranged at the lower end of the defogger tower, a smoke outlet is arranged at the upper end of the defogger tower; a liquid collecting outlet is arranged at the bottom end of the defogger; the acid collecting tank is arranged below the defogger, the acid collecting tank is provided with a liquid inlet and a liquid outlet, and the liquid inlet of the acid collecting tank is connected with the liquid collecting outlet of the defogger; one end of the acid transport pipeline is arranged outside the defogger tower, and the other end passes through the reserved opening of the defogger tower and is connected with the liquid outlet of the acid collecting tank, and an acid discharge valve is also arranged on the acid transport pipeline; the smoke inlet of the defogger tower is connected with the smoke outlet of the previous stage defogger tower.
2. A method for reducing SO4 in flue gas according to claim 1. 2- concentration demisting system, characterized in that, The demister is a fiber demister.
3. A method for reducing SO4 in flue gas according to claim 1. 2- concentration demisting system, characterized in that, It also includes a secondary demisting net, which is obliquely arranged in the demisting tower and located above the demisting device.
4. A method for reducing SO4 in flue gas according to claim 3 2- concentration demisting system, characterized in that, The secondary demisting net is provided with demisting fibers.
5. A method for reducing SO4 in flue gas according to claim 1 2- concentration demisting system, characterized in that, The demisting system for reducing the sulfate ion concentration in the flue gas comprises two stages of demisting devices connected in series.
6. A method for reducing SO4 in flue gas according to any one of claims 1 to 5 2- Concentration of mist removal system in SO2 production system.