Heat exchanger suitable for quartz sand pickling process
By using fluorinated polypropylene capillary tubes and an open heat exchanger structure made of PPH material, the problems of high heat loss, easy leakage, and unsuitability for intermittent use in existing quartz sand pickling processes have been solved, achieving a highly efficient and durable acid heating effect.
Patent Information
- Application Number
- CN202520220004.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-12
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2035-02-12
AI Technical Summary
In existing quartz sand pickling processes, graphite, silicon carbide, and polytetrafluoroethylene heat exchangers suffer from problems such as high heat loss, easy leakage, short lifespan, and unsuitability for intermittent use. Furthermore, the traditional heat exchanger structure results in a small heat exchange area, high heat loss, and easy blockage.
Fluorinated polypropylene (PFA) tubes are used as heat exchangers, combined with PPH material heat exchanger shells, and designed as open structures. The tube bundles are supported by support grates to achieve intermittent heating of acid liquid. Saturated steam is used for heating and hot acid liquid is extracted by acid pumps to avoid continuous circulation.
It achieves high temperature resistance, leak-proof design, low heat consumption, and large heat exchange area, making it suitable for the intermittent heating requirements of quartz sand pickling process, thus reducing failure rate and heat loss.
Smart Images
Figure CN223769307U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of quartz sand production, and in particular to a heat exchanger suitable for the acid washing process of quartz sand. Background Technology
[0002] Currently, the acid washing process for quartz sand requires heating the acid solution to improve the washing effect. However, most acid heating uses graphite heat exchangers or silicon carbide heat exchangers, which have the following disadvantages:
[0003] 1) Heat exchangers are mostly made of graphite, silicon carbide, or polytetrafluoroethylene (PTFE). Graphite heat exchangers heat graphite blocks with saturated steam, and the cold acid liquid is heated as it passes through the graphite pores. Therefore, the heat exchange area is small, resulting in significant heat loss. Silicon carbide heat exchangers have a larger heat exchange area and lower heat consumption compared to graphite heat exchangers, but they are more expensive, prone to cracking, and have a shorter service life. A small number use PTFE hair tubes as heat exchangers, but because this material is molded, it is prone to pores during production. During use, acid liquid can easily leak into the heat exchange tubes and be discharged, causing acid waste and damage to related pipelines. In addition, this material is relatively hard, has a low thermal conductivity, and has high heat consumption. Furthermore, the outer shell of ordinary heat exchangers is made of metal, with only the inside of the metal shell coated or lined with acid and alkali resistant material. Therefore, the caps at both ends of the shell are easily corroded by pressurized hot acid liquid, resulting in leakage and a very high failure rate.
[0004] 2) Graphite heat exchangers or silicon carbide heat exchangers are all closed containers of shell and tube type, plate and frame type or tube and shell type. The heat exchange blocks or tubes of shell and tube type, plate and frame type, and tube and shell type heat exchangers are almost at the same height as the shell and are evenly arranged in the shell. The acid must fill the entire shell (container), which is bound to be a continuous and uninterrupted use process. It is not suitable for the intermittent use method of heating the cold acid in the container, taking it all out, refilling the cold acid, heating it again, and taking it all out again.
[0005] 3) Regardless of whether it's a shell-and-tube, plate-and-frame, or tubular heat exchanger, all heat exchangers involve uniformly fixing tubes or plates / frames that have been saturated with steam within a sealed container shell. Cold acid is then continuously injected into the container from the top (or bottom), heated, and continuously pressurized before being discharged for use. This is a cyclical operating state where cold acid is continuously injected and hot acid is continuously discharged from the shell. Therefore, it is prone to problems such as small heat exchange area, high heat loss, and easy blockage. Utility Model Content
[0006] To address the technical problems existing in the background art, this utility model provides a heat exchanger suitable for the quartz sand pickling process, which uses fluorinated polypropylene (PFA) thin tubes as the heat exchanger, and has the characteristics of being soft and leak-proof, resistant to high temperature of 260℃, and having good heat exchange effect.
[0007] The technical solution of this utility model is as follows: This utility model is a heat exchanger suitable for the quartz sand pickling process, characterized in that: the heat exchanger suitable for the quartz sand pickling process includes a heat exchanger shell, a saturated steam pipe, and a condensate discharge pipe; a support grate is horizontally arranged in the lower part of the heat exchanger shell, and a thin tube bundle is arranged on the support grate; flange holes for connecting the thin tube bundle with the saturated steam pipe and the condensate discharge pipe are provided on both sides of the heat exchanger shell; the thin tube bundle is made of fluorinated polypropylene, and both ends of the thin tube bundle pass through the flange holes provided on the heat exchanger shell wall, one end being the saturated steam inlet and the other end being the condensate outlet; the saturated steam inlet is connected to the saturated steam pipe, and the condensate outlet is connected to the condensate discharge pipe.
[0008] Furthermore, the heat exchanger shell is made of PPH material.
[0009] Furthermore, both the saturated steam pipe and the condensate discharge pipe are connected to the flange hole via an external reducing flange.
[0010] Furthermore, the thin tube bundles are arranged in three groups, in the form of coils, in a centrally symmetrical manner on the support grate, with the saturated steam pipes and condensate discharge pipes corresponding to the three groups.
[0011] Furthermore, a thin tube bundle fixing bracket is provided on the support grate plate, and the thin tube bundle is placed on the support grate plate through the fixing bracket.
[0012] Furthermore, a new acid supply pipe is provided above the heat exchanger shell, which is connected to the heat exchanger shell, and a hot acid injection pipe is provided on the heat exchanger shell below the support grate, which is connected to the heat exchanger shell and is connected to the reaction vessel.
[0013] Furthermore, an acid pump is installed on the pipeline for injecting hot acid into the reactor.
[0014] Furthermore, an acid mist recovery pipe and a reaction vessel overflow acid circulation pipe are installed above the heat exchanger shell and connected to the heat exchanger shell.
[0015] Furthermore, a slag discharge port is provided on the heat exchanger shell below the supporting grate.
[0016] This invention provides a heat exchanger suitable for quartz sand pickling processes. The heat exchanger's fine tube bundles are made of fluorinated polypropylene (PFA) tubes, which are melt-drawn into shape after being heated to 360°C. This process does not produce pores and features softness, no cracking or leakage, resistance to 260°C high temperatures, and good heat exchange performance. Furthermore, the heat exchanger shell containing the acid is also made of acid- and alkali-resistant PPH material. Since there is no pressure inside the heat exchanger shell, it will not crack or leak. The heat exchanger body of this invention consists of several 20m long fluorinated polypropylene tubes (6×4mm in diameter) inserted into perforated PPH material fixing brackets and fixed together. Three such tube bundles are symmetrically placed on a support grate at the bottom of the PPH material heat exchanger shell and continuously immersed in the acid solution at the bottom. Then, saturated steam is connected to the hose, and a certain amount of acid (based on the amount of acid needed in production) is injected. The acid is heated to about 80°C using hot steam passing through the thin tube bundle. The hot acid from the upper part of the thin tube bundle (about 1 meter from bottom to top) is then extracted for use using an acid pump. If more hot acid is needed, a certain amount of cold acid is injected back into the tank and reheated. Therefore, this invention has the following advantages:
[0017] 1) This utility model uses a thin tube of fluorinated polypropylene (PFA) as a heat exchanger, which has the advantages of being semi-transparent, having fast heat conduction, low heat consumption, and being leak-proof, resulting in good performance.
[0018] 2) This utility model uses a thin tube of fluorinated polypropylene (PFA) as a heat exchanger, which is resistant to acids and alkalis (especially hydrofluoric acid), can withstand high temperatures of 260℃, and can be directly immersed in acid solution. It has direct heat exchange, large heat exchange area, low heat consumption, and no leakage. It is also particularly suitable for the intermittent heating requirements of acid solution in the quartz sand pickling process.
[0019] 3) During the use of this utility model, since saturated steam flows through the hose, the hose will not be blocked; the heat exchange hose is placed in an open tank, making it easy to remove and maintain; it does not leak and has few malfunctions; it has a large heat exchange area, low heat consumption, and excellent effect. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structure of this utility model;
[0021] Figure 2 This is a schematic diagram of the supporting grate structure of this utility model;
[0022] Figure 3 This is a schematic diagram of a thin tube bundle in a specific embodiment of this utility model;
[0023] Figure 4 This is a schematic diagram of the saturated steam pipe and condensate discharge pipe in a specific embodiment of this utility model.
[0024] The annotations in the attached figures are explained as follows:
[0025] 1. Acid mist recovery pipeline; 2. Reactor overflow acid circulation pipeline; 3. New acid replenishment pipeline; 4. Heat exchanger shell; 5. Saturated steam pipeline; 6. Hot acid injection pipeline to reactor; 7. Thin tube bundle; 8. Condensate discharge pipeline; 9. Slag discharge port; 10. Thin tube bundle fixing bracket; 11. Support grate; 12. Acid pump; 13. Condensate outlet; 14. Saturated steam inlet. Detailed Implementation
[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0027] See Figure 1 The structure of this utility model embodiment includes a heat exchanger shell 4. A supporting grate 11 is laterally arranged in the lower part of the heat exchanger shell 4. A thin tube bundle 7 is arranged on the supporting grate 11. Flange holes are provided on both sides of the supporting grate 11 on the heat exchanger shell 4 for connecting the thin tube bundle 7 to the saturated steam pipe 5 and the condensate discharge pipe 8. The thin tube bundle 7 is made of fluorinated polypropylene. Both ends of the thin tube bundle 7 pass through the flange holes provided on the wall of the heat exchanger shell 4. One end of the thin tube bundle 7 is a saturated steam inlet 14, and the other end is a condensate outlet 13. The saturated steam inlet 14 is connected to the saturated steam pipe 5, and the condensate outlet 13 is connected to the condensate discharge pipe 8. The heat exchanger shell 4 is made of PPH material.
[0028] Both the saturated steam pipe 5 and the condensate discharge pipe 8 are connected to the flange holes via external reducing flanges (acid and alkali resistant, leak-proof). A replenishment acid pipe 3, communicating with the heat exchanger shell 4, is located above the heat exchanger shell 4. A hot acid injection pipe 6, communicating with the heat exchanger shell 4, is located on the heat exchanger shell 4 below the supporting grate 11. An acid pump 12 is installed on the hot acid injection pipe 6. An acid mist recovery pipe 1 and a reactor overflow acid circulation pipe 2, communicating with the heat exchanger shell 4, are located above the heat exchanger shell 4. A slag discharge port 9 is located on the heat exchanger shell 4 below the supporting grate 11.
[0029] See Figure 2 The support grate 11 of this utility model is circular and has multiple holes on it to allow acid to pass through.
[0030] See Figure 3 , 4In a preferred embodiment of this invention, the thin tube bundles 7 are arranged in three groups, symmetrically arranged in the form of coils on the supporting grate plate 11. A thin tube bundle fixing bracket 10 is provided on the supporting grate plate 11, and the thin tube bundles 7 are mounted on the supporting grate plate 11 through the thin tube bundle fixing bracket 10. The saturated steam pipes 5 and condensate discharge pipes 8 are arranged in three groups. The higher outer interface on one side of the heat exchanger shell 4 is the saturated steam inlet 14, connected to the saturated steam pipe 5. The lower outer interface on one side of the heat exchanger shell 4 is the condensate outlet 13, connected to the condensate discharge pipe 8.
[0031] This invention involves inserting several 20m long thin tube bundles 7 (6×4mm diameter) of fluorinated polypropylene into perforated PPH material fixing brackets 10 and fixing them as a group. Three such groups of thin tube bundles 7 are placed symmetrically on the support grate 11 at the bottom of the PPH material heat exchanger shell 4 and immersed in acid solution at the bottom for a long period of time. Then, saturated steam is connected to the thin tube bundles 7, and a certain amount of acid solution (based on the amount of acid solution required in production) is injected through the new acid solution replenishment pipe 3. The acid solution is heated to about 80°C by the hot steam passing through the thin tube bundles 7. The hot acid solution at the top of the thin tube bundles 7 (about 1 meter from bottom to top) is then pumped into the reactor pipe 6 for use using the acid pump 12. If hot acid solution is needed again, a certain amount of cold acid solution is injected into the heat exchanger shell 4 through the new acid solution replenishment pipe 3 for reheating. The acid solution overflowing from the reactor can also enter the heat exchanger shell 4 through the overflow acid solution inlet 2 for recycling. During the heat exchange process, the condensate formed by the hot steam in the thin tube bundle 7 is discharged from the condensate outlet 8. The acid mist formed inside the heat exchanger shell 4 is discharged into the acid mist tower through the acid mist recovery pipe 1. The residue is discharged from the slag discharge port 9.
[0032] The content of this utility model and the technical content not specifically described in the above embodiments are the same as the prior art.
[0033] The above are merely specific embodiments disclosed in this utility model, but the scope of protection disclosed in this utility model is not limited thereto. The scope of protection disclosed in this utility model shall be determined by the scope of protection of the claims.
Claims
1. A heat exchanger suitable for a quartz sand pickling process, characterized in that: The heat exchanger suitable for the quartz sand pickling process comprises a heat exchanger shell, a saturated steam pipeline and a condensed water discharge pipeline; a support grate is transversely arranged at the lower part of the heat exchanger shell, a fine tube bundle is arranged on the support grate, flange holes for connecting the fine tube bundle with the saturated steam pipeline and the condensed water discharge pipeline are arranged on the heat exchanger shell at both sides of the support grate; the fine tube bundle is made of fluorinated polypropylene material, the two ends of the fine tube bundle pass through the flange holes arranged on the wall of the heat exchanger shell, one end is a saturated steam inlet, and the other end is a condensed water outlet; the saturated steam inlet is connected with the saturated steam pipeline, and the condensed water outlet is connected with the condensed water discharge pipeline.
2. The heat exchanger suitable for quartz sand pickling process according to claim 1, characterized in that: The heat exchanger shell is made of PPH material.
3. The heat exchanger suitable for quartz sand pickling process according to claim 2, characterized in that: The saturated steam pipeline and the condensed water discharge pipeline are connected with the flange holes through external variable flanges.
4. The heat exchanger suitable for quartz sand pickling process according to claim 3, characterized in that: The fine tube bundle is in the form of coil and is arranged on the support grate in a central symmetrical manner, and the saturated steam pipeline and the condensed water discharge pipeline correspond to three groups.
5. The heat exchanger suitable for quartz sand pickling process according to claim 4, characterized in that: The support grate is provided with a fine tube bundle fixing support, and the fine tube bundle is arranged on the support grate through the fine tube bundle fixing support.
6. The heat exchanger suitable for quartz sand pickling process according to any one of claims 1 to 5, characterized in that: A supplementary new acid liquid pipeline in communication with the heat exchanger shell is arranged above the heat exchanger shell, and a hot acid liquid injection to a reaction kettle pipeline in communication with the heat exchanger shell is arranged on the heat exchanger shell below the support grate.
7. The heat exchanger suitable for quartz sand pickling process according to claim 6, characterized in that: An acid pump is arranged on the hot acid liquid injection to a reaction kettle pipeline.
8. The heat exchanger suitable for quartz sand pickling process according to claim 7, characterized in that: An acid mist recovery pipeline and a reaction kettle overflow acid liquid circulation pipeline in communication with the heat exchanger shell are arranged above the heat exchanger shell.
9. The heat exchanger suitable for quartz sand pickling process according to claim 8, characterized in that: A slag discharge port is arranged on the heat exchanger shell below the support grate.