A dry process for treating carbide slag

Abstract

This utility model relates to the field of calcium carbide decomposition and acetylene recovery technology in dry-process calcium carbide slag, and discloses a dry-process calcium carbide slag treatment system. The system includes: a calcium carbide decomposition reactor, a heat recovery unit, a gas-liquid separation device, and a steam generation unit. The heat recovery unit is connected to the mixed gas outlet of the calcium carbide decomposition reactor, and the steam generation unit is connected to the steam inlet of the calcium carbide decomposition reactor. Both the gas-liquid separation device and the steam generation unit are connected to the heat recovery unit. The calcium carbide decomposition reactor includes a shell, a rotary motor, several rake-type components, and several jet discs. This system can not only reduce the calcium carbide content in the calcium carbide slag to within a safe range without increasing the water content, but also continuously recover acetylene gas, promoting the reaction and greatly reducing the environmental pollution caused by the mixed gas.

Description

Technical Field

[0001] This utility model relates to the field of epoxy resin materials, and specifically to a dry process carbide slag treatment system. Background Technology

[0002] Calcium carbide is an upstream raw material for the production of polyvinyl chloride (PVC). There are two processes for reacting calcium carbide with water to produce acetylene: a wet process and a dry process. The more advanced process is the dry process, which involves spraying a small amount of water onto the calcium carbide to produce acetylene and calcium carbide slag. The calcium hydroxide deposited on the surface of the calcium carbide can be removed by agitation or a rake. While the dry process reduces wastewater, the equipment is more complex, and the resulting calcium carbide slag still contains 2-3% calcium carbide residue, along with 2-10% water. Therefore, the calcium carbide slag, once stored in a warehouse, will continue to release acetylene, causing environmental pollution. Furthermore, the explosive limit of acetylene is 2.3%. During storage, the calcium carbide slag can absorb moisture and generate large amounts of acetylene, which, under poor ventilation, can easily reach the explosive limit, posing an explosion risk.

[0003] Currently, there are two main methods for treating calcium carbide in dry-process calcium carbide slag. One method involves allowing the acetylene to fully release and reach relative stability through static settling. However, if the calcium carbide slag decomposes upon contact with water during later application, and the system is a closed system, acetylene accumulation exceeding the explosion limit may occur. The other method involves adding water for destruction. However, adding too little water results in incomplete destruction of the calcium carbide, while adding too much water produces sludge that can easily seep into the ground and pollute the environment. Furthermore, the high water content of the calcium carbide slag makes transportation inconvenient. Therefore, calcium carbide slag that has undergone water destruction still requires filtration and drying, which undoubtedly increases processing costs.

[0004] Therefore, how to efficiently recover calcium carbide from dry-process calcium carbide slag as a resource without adding water and without generating new pollution is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to overcome the problems of easy accumulation of acetylene gas and excessively high water content in the treated calcium carbide slag in existing calcium carbide slag treatment processes. This invention provides a dry calcium carbide slag treatment system that can reduce the calcium carbide content in the calcium carbide slag to within a safe range without increasing the water content. In addition, it can continuously recover acetylene gas, promote the reaction, and greatly reduce the pollution of the mixed gas to the environment.

[0006] To achieve the above objectives, the first aspect of this utility model provides a dry calcium carbide slag treatment system, which includes: a calcium carbide decomposition reactor, a heat recovery unit, a gas-liquid separation device, and a steam generation unit, wherein the heat recovery unit is connected to the mixed gas outlet of the calcium carbide decomposition reactor, the steam generation unit is connected to the steam inlet of the calcium carbide decomposition reactor, and both the gas-liquid separation device and the steam generation unit are connected to the heat recovery unit.

[0007] The calcium carbide decomposition reactor includes a shell, a rotary motor, several rake-type components, and several jet discs. The rotary motor is located at the top of the shell, and the output end of the rotary motor is provided with a rotating shaft that passes through the several jet discs in sequence. The several rake-type components are arranged on the rotating shaft, and each rake-type component is arranged above a jet disc. The several jet discs are arranged alternately from top to bottom.

[0008] Preferably, the jet disk is a hollow disc-shaped structure with a diameter of 2-5m and a height of 3-8m.

[0009] Preferably, the jet disc has a plurality of jet holes arranged along its circumferential direction on the surface near the corresponding rake component, and the jet holes are connected to the steam generating unit through an air guide pipe.

[0010] Preferably, the porosity of the jet disc surface is 15-20%.

[0011] Preferably, the rake assembly includes a rake arm fixed from top to bottom on the rotating shaft and a plurality of rake blades disposed at the lower end of the rake arm, wherein the plurality of rake blades on the rake arm are respectively disposed directly above the corresponding jet disc.

[0012] Preferably, in the rake assembly, the spacing between adjacent rake blades is 5-20 cm.

[0013] Preferably, in the rake assembly, a scraper is provided at the lower end of the rake blade, and a rubber protective pad is provided at the end of the scraper.

[0014] Preferably, along the axial direction of the rotation axis from top to bottom, the first layer of jet disks is positioned at a certain distance from the rotation axis at its center, and a first guide plate is provided at the end of the jet disk away from the rotation axis; the second layer of jet disks is positioned with a clearance fit at its center to the rotation axis, and a second guide plate is provided at the end of the jet disk close to the rotation axis; the third layer of jet disks is positioned at a certain distance from the rotation axis at its center, and a third guide plate is provided at the end of the jet disk away from the rotation axis; the fourth layer of jet disks is positioned with a clearance fit at its center to the rotation axis, and a fourth guide plate is provided at the end of the jet disk close to the rotation axis, and so on.

[0015] Preferably, the interior of the calcium carbide decomposition reactor is further provided with a first barrier net and a second barrier net, arranged from top to bottom along the axial direction of the rotation axis. The first barrier net is located above the uppermost jet disk, and the second barrier net is located below the lowermost jet disk.

[0016] Preferably, the heat recovery mechanism includes a primary heat exchanger, a secondary heat exchanger, and a condenser connected in sequence. The primary heat exchanger is connected to the calcium carbide decomposition reactor, and the condenser is connected to the gas-liquid separation device.

[0017] Preferably, the steam generating unit includes an evaporator, a centrifugal pump, and a water tank. The acetylene separation mechanism, the water tank, the centrifugal pump, the secondary heat exchanger, and the evaporator are connected in sequence, and the evaporator is connected to the calcium carbide decomposition reactor.

[0018] The dry calcium carbide slag treatment system of this invention improves the reaction efficiency between materials and steam by setting a special structure inside the calcium carbide decomposition reactor. Simultaneously, steam from the jet nozzle continuously carries out the acetylene gas produced from the reaction between the calcium carbide slag and steam, further promoting the reaction. This dry calcium carbide slag treatment system can reduce the calcium carbide content of dry calcium carbide slag to below 0.6% within 4 hours, while also recovering waste heat, further improving energy utilization efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the dry carbide slag treatment system described in this utility model.

[0020] Figure Labels

[0021] 1. Calcium carbide decomposition reactor; 2. Shell; 3. Rotary motor; 4. Rake assembly; 5. Jet disc; 6. Rotating shaft; 7. First barrier screen; 8. Second barrier screen; 9. Heat recovery unit; 10. Primary heat exchanger; 11. Secondary heat exchanger; 12. Condenser; 13. Gas-liquid separation device; 14. Steam generation unit; 15. Evaporator; 16. Centrifugal pump; 17. Water tank; 18. Mixed gas outlet; 19. Steam inlet; 20. Calcium carbide slag inlet; 21. Calcium carbide slag outlet. Detailed Implementation

[0022] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] Figure 1 A schematic diagram of an exemplary dry calcium carbide slag treatment system is shown. The system includes: a calcium carbide decomposition reactor 1, a heat recovery unit 9, a gas-liquid separation device 13, and a steam generation unit 14. The heat recovery unit 9 is connected to the mixed gas outlet 18 of the calcium carbide decomposition reactor 1, the steam generation unit 14 is connected to the steam inlet 19 of the calcium carbide decomposition reactor 1, and both the gas-liquid separation device 13 and the steam generation unit 14 are connected to the heat recovery unit 9.

[0025] The calcium carbide decomposition reactor 1 includes a shell 2, a rotary motor 3, several rake-type components 4, and several jet disks 5. The rotary motor 3 is located at the top of the shell 2. The output end of the rotary motor 3 is provided with a rotating shaft 6 that passes through the several jet disks 5 in sequence. The several rake-type components 4 are arranged on the rotating shaft 6, and each rake-type component 4 is arranged above a jet disk 5. The several jet disks 5 are arranged alternately from top to bottom.

[0026] In this exemplary embodiment, the jet disk 5 has a plurality of jet holes arranged along its circumferential direction on the surface near the corresponding rake component 4. The jet holes are connected to the steam generating unit 14 through a gas guide pipe. Steam from the steam generating unit 14 enters the calcium carbide decomposition reactor 1 through the jet holes and reacts with the dry calcium carbide slag material.

[0027] In a preferred embodiment, the jet disk 5 can be a hollow disc-shaped structure. The steam generating unit 14 is connected to the hollow part of the jet disk 5 through a gas guide pipe, and a plurality of jet holes are arranged along its circumferential direction on the surface near the corresponding rake component 4. According to this preferred embodiment, the steam continuously ejected from the jet holes can contact and react with the dry carbide slag material on the jet disk 5, while continuously carrying out the acetylene gas produced by the reaction, further promoting the reaction.

[0028] More preferably, the diameter of the jet disk 5 can be 2-5m, more preferably 2.5-3.5m; the height can be 3-8m, more preferably 4-6m; and the porosity on the surface of the jet disk 5 can be 15-20%, more preferably 17-19%. In these preferred embodiments, when the specifications of the jet disk 5 and the porosity on its surface are within the above-mentioned ranges (especially the preferred ranges), the reaction between the steam from the jet holes and the dry carbide slag material on the jet disk 5 proceeds more rapidly and thoroughly.

[0029] In this exemplary embodiment, the rake assembly 4 includes a rake arm fixed from top to bottom on the rotating shaft 6 and a plurality of rake blades disposed at the lower end of the rake arm. Each rake blade is positioned directly above a corresponding jet disk 5. According to this exemplary embodiment, the rake blades can disperse and push the dry carbide slag material on the corresponding jet disk 5 to the next jet disk 5, allowing the carbide slag to react with the steam multiple times and achieving continuous discharge of the carbide slag.

[0030] In a preferred embodiment, the spacing between adjacent rake blades in the rake assembly 4 can be 5-20 cm, more preferably 10-15 cm. In these preferred embodiments, when the spacing between adjacent rake blades is within the above-mentioned preferred range, the dry carbide slag material is more evenly agitated and dispersed on the air jet disc 5.

[0031] More preferably, in the rake assembly 4, a scraper is correspondingly provided at the lower end of the rake blade, and a rubber protective pad is provided at the end of the scraper. According to this preferred embodiment, the scraper can further increase the dispersion and pushing effect of the rake blade on the material, and the rubber protective pad can reduce the wear between the scraper and the air jet disc 5.

[0032] In this exemplary embodiment, along the axial direction of the rotation axis 6 from top to bottom, the first layer of jet disks 5 are arranged at a certain distance from the rotation axis 6 at their axial center, and a first guide plate is provided at the end of the jet disk 5 away from the rotation axis 6; the second layer of jet disks 5 are clearance-fitted to the rotation axis 6 at their axial center, and a second guide plate is provided at the end of the jet disk 5 near the rotation axis 6; the third layer of jet disks 5 are arrangement at a certain distance from the rotation axis 6 at their axial center, and a third guide plate is provided at the end of the jet disk 5 away from the rotation axis 6; the fourth layer of jet disks 5 are clearance-fitted to the rotation axis 6 at their axial center, and a fourth guide plate is provided at the end of the jet disk 5 near the rotation axis 6, and so on. In this exemplary embodiment, the material on the first layer of jet disk 5 can be dispersed and pushed onto the second layer of jet disk 5 at the end of the first layer of jet disk 5 near the rotating shaft 6, and the material on the second layer of jet disk 5 can be dispersed and pushed onto the third layer of jet disk 5 at the end of the second layer of jet disk 5 away from the rotating shaft 6, and so on, so as to achieve the effect of dispersing the material layer by layer.

[0033] In this exemplary embodiment, the interior of the calcium carbide decomposition reactor 1 is further provided with a first barrier net 7 and a second barrier net 8. Along the axial direction of the rotation axis 6 from top to bottom, the first barrier net 7 is located above the uppermost jet disk 5, and the second barrier net 8 is located below the lowermost jet disk 5. According to this exemplary embodiment, the first barrier net 7 and the second barrier net 8 can further prevent the material added to the calcium carbide decomposition reactor 1 from falling directly to the bottom of the reactor body 1 without passing through each layer of jet disks 5.

[0034] In this exemplary embodiment, the heat recovery mechanism 9 includes a primary heat exchanger 10, a secondary heat exchanger 11, and a condenser 12 connected in sequence. The primary heat exchanger 10 is connected to the calcium carbide decomposition reactor 1 via a mixed gas outlet 18 and a calcium carbide slag inlet 20 located at the upper end of the shell 2. The gaseous products from the calcium carbide decomposition reactor 1 enter the primary heat exchanger 10 through the mixed gas outlet 18 to exchange heat with the dry calcium carbide slag. The gaseous products after heat exchange enter the secondary heat exchanger 11 for secondary heat exchange. The dry calcium carbide slag after heat exchange enters the calcium carbide decomposition reactor 1 through the calcium carbide slag inlet 20 for decomposition reaction. The gaseous products in the secondary heat exchanger 11 enter the condenser 12 after heat exchange to condense the steam, and then enter the gas-liquid separation device 13 for gas-liquid separation. According to this exemplary embodiment, the primary heat exchanger 10 and the secondary heat exchanger 11 can recover waste heat from the gaseous products of the calcium carbide decomposition reactor 1, and the dry calcium carbide slag can be preheated in the primary heat exchanger 10, further reducing energy consumption.

[0035] In this exemplary embodiment, the steam generating unit 14 includes an evaporator 15, a centrifugal pump 16, and a water tank 17. The gas-liquid separation device 13, the water tank 17, the centrifugal pump 16, the secondary heat exchanger 11, and the evaporator 15 are connected in sequence. The bottom of the gas-liquid separation device 13 is connected to the water tank 17, and the top is provided with an acetylene gas outlet. When it is necessary to inject steam into the reactor body 1, the centrifugal pump 16 can extract the water recovered from the water tank 17 and send it to the secondary heat exchanger 11 for heat exchange. Finally, it is sent to the evaporator 15 for evaporation to generate steam at a certain temperature. The amount of steam generated is controlled by the heating power of the evaporator 12, and the temperature of the steam is controlled by the system pressure. The steam enters the calcium carbide decomposition reactor 1 through the steam inlet 19 provided at the bottom of the shell 2.

[0036] The method for treating dry calcium carbide slag according to this utility model includes: steam from the steam generation unit enters the calcium carbide decomposition reactor to replace the oxygen in the calcium carbide decomposition reactor; then, dry calcium carbide slag is added to the calcium carbide decomposition reactor through a primary heat exchanger; a rotary motor is started to make the dry calcium carbide slag react with the steam; the solid phase product obtained from the reaction is discharged from the calcium carbide decomposition reactor; the gas phase product obtained from the reaction is passed through a primary heat exchanger and a secondary heat exchanger for heat exchange, then enters a condenser for condensation, and finally enters a gas-liquid separation device to separate acetylene gas.

[0037] In the method described in this invention, the reaction conditions may further include: an oxygen content ≤0.5% by volume, preferably 0.01-0.3% by volume; a pressure of 0.15-0.4 MPa, preferably 0.2-0.35 MPa; and a temperature of 100-143°C, preferably 120-143°C. In the method described in this invention, when the reaction conditions are within the above ranges (especially the preferred ranges), the reaction between the dry-process carbide slag and the steam proceeds more rapidly and thoroughly.

[0038] In the method described in this invention, the thickness of the dry calcium carbide slag in the calcium carbide decomposition reactor can be 1-3 cm, preferably 1.5-2.5 cm; the residence time can be 3-7 h, preferably 4-6 h. In the method described in this invention, when the thickness and residence time of the dry calcium carbide slag are within the above-mentioned ranges (especially the preferred ranges), the reaction between the dry calcium carbide slag and the steam proceeds more rapidly and thoroughly.

[0039] In some embodiments, the dry process for treating calcium carbide slag specifically includes: turning on the centrifugal pump 16 to add water and generate steam into the evaporator 15, controlling the heating power of the evaporator 15 to be 5-10 kW and the system pressure to be 1-5 atm; the steam from the evaporator 15 is introduced into the bottom of the calcium carbide decomposition reactor 1 through the steam inlet 19 and replaces the oxygen in the calcium carbide decomposition reactor 1, and controlling the oxygen volume content to be ≤0.5% by volume. The outlet valve of the calcium carbide decomposition reactor 1 is adjusted to make the temperature inside the calcium carbide decomposition reactor 1 reach 100-143°C and the pressure reach 0.15-0.4 MPa. The heating power of the evaporator 15 is further controlled to be 5-10 kW, and the steam addition rate is set to 8-15 kg / h. Dry calcium carbide slag is added to the calcium carbide decomposition reactor 1 at a rate of 50-120 kg / h through a primary heat exchanger 10. Then, a rotary motor 3 is turned on, controlling the rotation speed of the rake assembly 4 to 10-30 rpm. The dry calcium carbide slag added to the calcium carbide decomposition reactor 1 forms a thickness of 1-3 cm on the jet plate 5. The dry calcium carbide slag remains in the calcium carbide decomposition reactor 1 for 3-7 hours before being discharged. After the reaction is complete, the dry calcium carbide slag is discharged from the calcium carbide decomposition reactor 1. The resulting mixed gas undergoes heat exchange through a primary heat exchanger 10 and a secondary heat exchanger 11 before entering a condenser 12 for condensation. It then enters a gas-liquid separator for gas-liquid separation to obtain acetylene gas. The recovered water is recycled into a water tank 17. According to this embodiment, the reaction efficiency between the steam and the dry calcium carbide slag is higher, and the purity of the resulting acetylene gas is higher.

[0040] The following embodiments further illustrate the dry carbide slag treatment system of this utility model. These embodiments are implemented based on the technical solution of this utility model, providing detailed implementation methods and specific operating procedures. However, the scope of protection of this utility model is not limited to the following embodiments.

[0041] Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods in the art.

[0042] Unless otherwise specified, all experimental materials used in the following examples are commercially available.

[0043] The following examples 1-7 are in Figure 1 The dry calcium carbide slag treatment system shown is implemented. The system includes: a calcium carbide decomposition reactor 1, a heat recovery unit 9, a gas-liquid separation device 13, and a steam generation unit 14. The heat recovery unit 9 is connected to the mixed gas outlet 18 of the calcium carbide decomposition reactor 1, the steam generation unit 14 is connected to the steam inlet 19 of the calcium carbide decomposition reactor 1, and both the gas-liquid separation device 13 and the steam generation unit 14 are connected to the heat recovery unit 9.

[0044] The calcium carbide decomposition reactor 1 includes a shell 2, a rotary motor 3, a five-layer rake assembly 4, and a five-layer jet disk 5. The rotary motor 3 is located at the top of the shell 2. The output end of the rotary motor 3 is provided with a rotating shaft 6 that passes through the five-layer jet disk 5 in sequence. The five-layer rake assembly 4 includes rake arms fixed from top to bottom on the rotating shaft 6 and 50 rake blades disposed at the lower end of the rake arms. The 50 rake blades on the rake arms are all disposed directly above the corresponding jet disk 5. In each layer of the rake assembly 4, the spacing between adjacent rake blades is 10 cm. The lower end of each rake blade is provided with a scraper, and the end of the scraper is provided with a rubber protective pad.

[0045] The jet disk 5 can be a hollow disc-shaped structure with a diameter of 3m and a height of 5m. The steam generating unit 14 is connected to the hollow part of the jet disk 5 through a gas guide pipe. Several jet holes are provided on the surface of the corresponding rake component 4 along its circumferential direction. The opening rate on the surface of the jet disk 5 is 18.2%.

[0046] Along the axial direction of the rotating shaft 6, the five layers of jet disks 5 are arranged alternately from top to bottom. The first layer of jet disks 5 is positioned 0.2m away from the rotating shaft 6 at its axis, and a first guide plate is provided at the end of the jet disk 5 away from the rotating shaft 6. The second layer of jet disks 5 is positioned with a clearance fit to the rotating shaft 6 at its axis, and a second guide plate is provided at the end of the jet disk 5 close to the rotating shaft 6. The third layer of jet disks 5 is positioned 0.2m away from the rotating shaft 6 at its axis, and a third guide plate is provided at the end of the jet disk 5 away from the rotating shaft 6. The fourth layer of jet disks 5 is positioned with a clearance fit to the rotating shaft 6 at its axis, and a fourth guide plate is provided at the end of the jet disk 5 close to the rotating shaft 6. The fifth layer of jet disks 5 is positioned 0.2m away from the rotating shaft 6 at its axis, and a fifth guide plate is provided at the end of the jet disk 5 away from the rotating shaft 6.

[0047] In the calcium carbide decomposition reactor 1, a first barrier net 7 is provided above the first layer of jet disk 5, and a second barrier net 8 is provided below the fifth layer of jet disk 5.

[0048] The heat recovery mechanism 9 includes a primary heat exchanger 10, a secondary heat exchanger 11 and a condenser 12 connected in sequence. The primary heat exchanger 10 is connected to the calcium carbide decomposition reactor 1 through a mixed gas outlet 18 and a calcium carbide slag inlet 20 located at the upper end of the shell 2.

[0049] The steam generating unit 14 includes an evaporator 15, a centrifugal pump 16, and a water tank 17. The gas-liquid separation device 13, the water tank 17, the centrifugal pump 16, the secondary heat exchanger 11, and the evaporator 15 are connected in sequence. The evaporator is connected to the calcium carbide decomposition reactor 1 through a steam inlet 19 located at the lower end of the shell 2. The bottom of the gas-liquid separation device 13 is connected to the water tank 17, and an acetylene gas outlet is provided at the top.

[0050] Example 1

[0051] (1) Start the centrifugal pump 16 to add water to the evaporator 15 and generate steam. Control the heating power of the evaporator 15 to 5kW and the system pressure to 5atm. The steam from the evaporator 15 is introduced into the bottom of the calcium carbide decomposition reactor 1 through the steam inlet 19 and replaces the oxygen in the calcium carbide decomposition reactor 1. Control the oxygen volume content to be about 0.05%. Adjust the outlet valve of the calcium carbide decomposition reactor 1 so that the temperature in the calcium carbide decomposition reactor 1 reaches 130℃ and the pressure is 0.13Mpa. Further control the heating power of the evaporator 15 to 5.75kW and set the steam addition rate to 9.2kg / h.

[0052] (2) Dry carbide slag is added to carbide decomposition reactor 1 through primary heat exchanger 10 at a rate of 70 kg / h. Then, the rotary motor 3 is turned on and the speed of the rake assembly 4 is controlled to be 10 rpm. The thickness of the dry carbide slag added to carbide decomposition reactor 1 on the jet plate 5 is 1.5 cm. The dry carbide slag is discharged from carbide decomposition reactor 1 after staying in carbide decomposition reactor 1 for 5 hours.

[0053] (3) After the reaction is completed, the dry carbide slag is discharged from the carbide decomposition reactor 1. The resulting mixed gas is condensed in the condenser 12 after heat exchange in the primary heat exchanger 10 and the secondary heat exchanger 11. Then it enters the gas-liquid separation device for gas-liquid separation to obtain acetylene gas. The recovered water enters the water tank 17 for recycling.

[0054] Sampling analysis revealed that the residual amount of calcium carbide in the dry-process calcium carbide slag of this embodiment was 0.15%.

[0055] Example 2

[0056] This embodiment is implemented according to the method described in Embodiment 1. The difference is that in step (2), the rate at which the dry carbide slag is added is 87 kg / h, and the dry carbide slag is discharged from the carbide decomposition reactor 1 after staying in the carbide decomposition reactor 1 for 4 hours.

[0057] Sampling analysis revealed that the residual amount of calcium carbide in the dry-process calcium carbide slag of this embodiment was 0.22%.

[0058] Example 3

[0059] This embodiment is implemented according to the method described in Embodiment 1, except that in step (1), the amount of steam added to the calcium carbide decomposition reactor 1 is set to 12.3 kg / h;

[0060] In step (2), the dry carbide slag is added at a rate of 117 kg / h, and the dry carbide slag is discharged from the carbide decomposition reactor 1 after staying in the carbide decomposition reactor 1 for 3 hours.

[0061] Sampling analysis revealed that the residual amount of calcium carbide in the dry-process calcium carbide slag of this embodiment was 0.36%.

[0062] Example 4

[0063] This embodiment is implemented according to the method described in Embodiment 1, except that in step (1), the temperature in the calcium carbide decomposition reactor 1 is controlled at 120°C, and the amount of steam added to the calcium carbide decomposition reactor 1 is set to 10.8 kg / h;

[0064] In step (2), the dry carbide slag is added at a rate of 117 kg / h, and the dry carbide slag is discharged from the carbide decomposition reactor 1 after staying in the carbide decomposition reactor 1 for 4 hours.

[0065] Sampling analysis revealed that the residual amount of calcium carbide in the dry-process calcium carbide slag of this embodiment was 0.31%.

[0066] Example 5

[0067] This embodiment is implemented according to the method described in Embodiment 1, except that in step (1), the temperature in the calcium carbide decomposition reactor 1 is controlled at 110°C, and the amount of steam added to the calcium carbide decomposition reactor 1 is set to 9.6 kg / h;

[0068] In step (2), the dry carbide slag is added at a rate of 87.6 kg / h, and the dry carbide slag is discharged from the carbide decomposition reactor 1 after staying in the carbide decomposition reactor 1 for 4 hours.

[0069] Sampling analysis revealed that the residual amount of calcium carbide in the dry-process calcium carbide slag of this embodiment was 0.35%.

[0070] Example 6

[0071] This embodiment is implemented according to the method described in Embodiment 1. The difference is that in step (1), the oxygen concentration in the calcium carbide decomposition reactor 1 is controlled to be 0.8% by volume and the temperature is 140°C. The amount of steam added to the calcium carbide decomposition reactor 1 is set to be 15 kg / h.

[0072] In step (2), the dry carbide slag is added at a rate of 120 kg / h, and the dry carbide slag added to the carbide decomposition reactor 1 has a thickness of 3 cm on the jet plate 5. The dry carbide slag is discharged from the carbide decomposition reactor 1 after staying in the carbide decomposition reactor 1 for 7 hours.

[0073] Sampling analysis revealed that the residual amount of calcium carbide in the dry-process calcium carbide slag of this embodiment was 0.47%.

[0074] Example 7

[0075] This embodiment is implemented according to the method described in Embodiment 1, except that in step (1), the temperature in the calcium carbide decomposition reactor 1 is controlled to be 160°C, and the amount of steam added to the calcium carbide decomposition reactor 1 is set to be 20 kg / h;

[0076] In step (2), the dry carbide slag is added at a rate of 150 kg / h, and the dry carbide slag added to the carbide decomposition reactor 1 has a thickness of 8 cm on the jet plate 5. The dry carbide slag is discharged from the carbide decomposition reactor 1 after staying in the carbide decomposition reactor 1 for 10 hours.

[0077] Sampling analysis revealed that the residual amount of calcium carbide in the dry-process calcium carbide slag of this embodiment was 1.05%.

[0078] Comparative Example 1

[0079] The traditional method of adding water to destroy calcium carbide in dry calcium carbide slag is adopted.

[0080] 100 kg of calcium carbide slag is loaded into a mixer. Then, 25 kg of water is gradually sprayed into the mixer and mixed with the calcium carbide over one hour. The mixture is then stirred for another 3 hours. During the spraying and stirring process, ventilation is provided to remove the generated acetylene gas in a timely manner.

[0081] Comparative Example 2

[0082] Add 100L of water to a 200L stirred tank, add 33kg of calcium carbide to the stirred tank under stirring conditions and continue stirring for 1 hour. Then pass the suspension into a plate and frame filter press for dehydration.

[0083] Test Example 1

[0084] This test example is used to detect the residual amount of calcium carbide in the dry calcium carbide slag after treatment in Examples 1-7.

[0085] S1. Weigh approximately 20g of the dry carbide slag sample obtained in Examples 1-7, with a mass of n1. Place the weighed sample in an evaporating dish and dry it at a temperature of 150℃ for 2 hours. After drying, remove the sample from the oven and place it on a desiccator to cool. Once the sample has returned to room temperature, weigh it and record the mass as n2.

[0086] S2. Add water to the treated dry carbide slag sample, stir until it becomes a paste, and then hydrolyze it. Then put the sample into an oven to dry at 150℃ for 3 hours. After constant weight, take out the sample, cool it, weigh it, and record the mass as n3.

[0087] To eliminate the influence of CO2 during the analysis, a blank sample test was also conducted: approximately 20g of calcium carbide slag was weighed, added with water, and stirred until a paste was formed. This sample was used as a blank sample to repeat the above steps S1 and S2, yielding masses N1, N2, and N3, respectively.

[0088] The formula for calculating the residual calcium carbide content in the treated dry-process calcium carbide slag is as follows:

[0089] Residual calcium carbide content (wt%) = [5.22] × (n3-n2) / n1-5.22 × [(N3-N2)N1]×100%.

[0090] Test Example 2

[0091] This test example is used to detect the moisture content in the dry carbide slag treated in Examples 1-7 and Comparative Examples 1-2. The specific experimental steps are as follows:

[0092] Weigh approximately 20g of the dry carbide slag samples obtained in Examples 1-7 and Comparative Examples 1-2. The mass of the dry carbide slag is n1. Place the weighed sample in an evaporating dish and dry it at a temperature of 150℃ for 2 hours. After drying, remove the sample from the oven and place it on a desiccator to cool. Once the sample has returned to room temperature, weigh it and record the mass as n2.

[0093] The formula for calculating the moisture content in the treated dry carbide slag is as follows:

[0094] Moisture content (wt%) = (n1-n2) / n1 × 100%

[0095] The results are shown in Table 1.

[0096] Test Example 3

[0097] This test example is used to detect the acetylene content in the acetylene gas obtained after treatment in Examples 1-7 and Comparative Examples 1-2. The specific experimental procedures were carried out in accordance with T / CCASC 3003—2023 "Determination of Acetylene Content in Calcium Carbide Slag by Gas Chromatography" published by the China Chlor-Alkali Industry Association.

[0098] The results are shown in Table 1.

[0099] Table 1

[0100] serial number Moisture content in carbide slag / % <![CDATA[Acetylene gas collection volume / L·h -1 > Acetylene content / % Example 1 2.37 524 95.8 Example 2 1.91 627 96.2 Example 3 1.89 675 97.1 Example 4 2.23 599 96.7 Example 5 1.97 588 96.5 Example 6 2.01 771 94.2 Example 7 5.73 681 88.6 Comparative Example 1 16.25 / / Comparative Example 2 36.71 / /

[0101] As shown in Table 1, compared with the traditional water-addition destruction method used in Comparative Examples 1 and 2, Examples 1-7, due to the use of the system of this invention, by using steam instead of the traditional water soaking, can not only reduce the calcium carbide content in the calcium carbide slag to within the safe limit without increasing the water content of calcium carbide, but also continuously recover acetylene gas, promote the reaction, and greatly reduce the pollution of the mixed gas to the environment. In the preferred Examples 1-6, due to the use of optimized reaction conditions, the water content in the calcium carbide slag obtained from the reaction is further reduced, and the purity of the obtained acetylene gas is higher.

[0102] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed by this utility model and are all within the protection scope of this utility model.

Claims

1. A dry process system for treating carbide slag, characterized in that, The system includes: a calcium carbide decomposition reactor (1), a heat recovery unit (9), a gas-liquid separation device (13), and a steam generation unit (14), wherein the heat recovery unit (9) is connected to the mixed gas outlet (18) of the calcium carbide decomposition reactor (1), the steam generation unit (14) is connected to the steam inlet (19) of the calcium carbide decomposition reactor (1), and both the gas-liquid separation device (13) and the steam generation unit (14) are connected to the heat recovery unit (9); The calcium carbide decomposition reactor (1) includes a shell (2), a rotary motor (3), several rake components (4) and several jet discs (5). The rotary motor (3) is located at the top of the shell (2). The output end of the rotary motor (3) is provided with a rotating shaft (6) that passes through the several jet discs (5) in sequence. The several rake components (4) are arranged on the rotating shaft (6), and each rake component (4) is arranged above a jet disc (5). The several jet discs (5) are arranged alternately from top to bottom.

2. The system according to claim 1, characterized in that, The jet disk (5) is a hollow disc-shaped structure with a diameter of 2-5m and a height of 3-8m.

3. The system according to claim 1 or 2, characterized in that, The jet disk (5) has several jet holes arranged along its circumferential direction on the surface near the corresponding rake assembly (4), and the jet holes are connected to the steam generating unit (14) through the air guide pipe.

4. The system according to claim 1 or 2, characterized in that, The porosity of the surface of the jet disk (5) is 15-20%.

5. The system according to claim 1 or 2, characterized in that, The rake assembly (4) includes a rake arm fixed from top to bottom on the rotating shaft (6) and several rake blades disposed at the lower end of the rake arm. The several rake blades on the rake arm are respectively disposed directly above the corresponding jet disc (5).

6. The system according to claim 5, characterized in that, In the rake assembly (4), the spacing between adjacent rake blades is 5-20cm.

7. The system according to claim 5, characterized in that, In the rake assembly (4), a scraper is provided at the lower end of the rake blade, and a rubber protective pad is provided at the end of the scraper.

8. The system according to claim 1 or 2, characterized in that, Along the axial direction of the rotating shaft (6) from top to bottom, the first layer of jet disks (5) is arranged at a certain distance from the rotating shaft (6) at its center, and a first guide plate is provided at the end of the jet disks (5) away from the rotating shaft (6); the second layer of jet disks (5) is in clearance fit with the rotating shaft (6) at its center, and a second guide plate is provided at the end of the jet disks (5) close to the rotating shaft (6); the third layer of jet disks (5) is arranged at a certain distance from the rotating shaft (6) at its center, and a third guide plate is provided at the end of the jet disks (5) away from the rotating shaft (6); the fourth layer of jet disks (5) is in clearance fit with the rotating shaft (6) at its center, and a fourth guide plate is provided at the end of the jet disks (5) close to the rotating shaft (6), and so on.

9. The system according to claim 1 or 2, characterized in that, The interior of the calcium carbide decomposition reactor (1) is also provided with a first barrier net (7) and a second barrier net (8). Along the axial direction of the rotating shaft (6) from top to bottom, the first barrier net (7) is located above the uppermost jet disk (5), and the second barrier net (8) is located below the lowermost jet disk (5).

10. The system according to claim 1 or 2, characterized in that, The heat recovery unit (9) includes a primary heat exchanger (10), a secondary heat exchanger (11) and a condenser (12) connected in sequence. The primary heat exchanger (10) is connected to the calcium carbide decomposition reactor (1), and the condenser (12) is connected to the gas-liquid separation device (13).

11. The system according to claim 10, characterized in that, The steam generating unit (14) includes an evaporator (15), a centrifugal pump (16) and a water tank (17). The gas-liquid separation device (13), the water tank (17), the centrifugal pump (16), the secondary heat exchanger (11) and the evaporator (15) are connected in sequence. The evaporator (15) is connected to the calcium carbide decomposition reactor (1).

Images