CN202511622U - Device using carbide slag to manufacture cement - Google Patents

Abstract

The utility model discloses a device for making cement by using calcium carbide slag, which includes a kiln tail smoke chamber, a rotary kiln, a preheater and a decomposition furnace; zone and zone II; the furnace body of zone I and zone II are equipped with pulverized coal nozzles; the top of the furnace body of zone I is equipped with an air outlet and a calcium carbide slag filter cake inlet, and the air outlet leads to the feed port of the preheater. There are dispersing devices and air rings in the furnace body in the area, and the air ring is located below the dispersing device; the auxiliary raw material inlet is opened on the side wall of the furnace body in the Ⅱ area, the tertiary air duct is connected to the furnace body in the Ⅱ area, and the bottom of the furnace body in the Ⅱ area is equipped with a smoke The mouth of the smoke chamber is narrowed, and the mouth of the smoke chamber leads to the kiln tail smoke chamber, and the discharge port of the kiln tail smoke chamber leads to the rotary kiln; an air lock is installed between the discharge port of the preheater and the feed port of the kiln tail smoke chamber. valve. Using the utility model can save power consumption; reduce unnecessary heat loss and save heat consumption; calcium carbide slag can be calcined directly in the rotary kiln after completing the preheating and decomposition process in the calciner, eliminating dead burning phenomenon and saving heat consumption.

Description

A device for making cement with calcium carbide slag

Technical field:

The utility model mainly relates to the technical field of cement preparation, in particular to a device for making cement with carbide slag.

Background technique:

The production of PVC in the chemical industry is divided into two types: calcium carbide method and ethylene method. The process route of calcium carbide method is calcium carbide → acetylene → polyethylene; the ethylene method relies on petroleum cracking. In order to prevent oil monopoly and resource depletion, the development of calcium carbide method is of strategic significance. Calcium carbide slag is the waste produced by hydrolysis of calcium carbide to produce acetylene gas. According to different slag removal methods, it can be divided into wet slag discharge and dry slag discharge. The main reaction formula of calcium carbide hydrolysis is: CaC ₂ (carbide)+2H ₂ O→C ₂ H ₂ ↑(acetylene gas)+Ca(OH) ₂ ↓(carbide slag). The moisture content of the wet-discharged carbide slag discharged from the acetylene generator is above 90%, and after concentration, the moisture content is still 70-80%, and the moisture content of the filter cake is about 35% after pressure filtration. Carbide slag particles are fine, and particles below 50 μm account for more than 80%, with high dispersion and strong water retention capacity. The main chemical composition of calcium carbide slag is Ca(OH) ₂ , and there are a little PH ₃ and H ₂ S gas residues, so it has a slight odor.

Carbide slag has strong alkalinity, it is easy to ash under natural storage conditions, it is easy to pollute groundwater, cause environmental pollution, and it is difficult to treat, which seriously restricts the development of calcium carbide process PVC industry. Ca(OH) ₂ in carbide slag can be decomposed by heat to obtain CaO, so it can be used as raw material for cement production. In recent years, the use of calcium carbide slag to produce cement has developed rapidly, and the "wet grinding and dry burning" process or the "dry grinding and dry burning" process are mainly used, both of which have shortcomings. In addition, there is also the "wet long kiln" process, which has been explicitly eliminated because of high energy consumption and does not conform to the national industrial policy, and will not be elaborated in this article.

There are two production methods in the "wet grinding and dry burning" process. One is to grind calcium carbide slag and auxiliary raw materials in a wet ball mill to make a slurry, then filter it into a raw filter cake, and then send it to a crushing dryer for drying. Dry. The second is to only send the calcium carbide slag filter cake into the crushing dryer, dry it into powder and then batch it, and then enter the rotary kiln to be calcined into cement clinker. The most criticized in the first method is that raw materials other than calcium carbide slag need to be added with water first and then dehydrated, resulting in high evaporation water. Strictly speaking, the latter method does not belong to "wet grinding and dry burning", but it uses a crushing dryer with the former, so it is stated together. Due to the high power of the crushing dryer, it must be placed on the ground, resulting in complicated process pipelines; and due to the harsh working conditions, the failure rate is high. Once a failure occurs, the kiln must be stopped for 10 days, resulting in a low operating rate of the production line. In addition, if the second method is used for cement production, once the crushing dryer overheats, it will directly threaten the production safety of subsequent equipment such as bag filter, so the operation and automation control level is extremely high.

The "dry grinding and dry burning" process is to send the calcium carbide slag filter cake to the rotary dryer for pre-drying to reduce its moisture to about 15%, and then mix it with auxiliary raw materials for drying and grinding with a vertical mill. Then sent to the rotary kiln for calcination. Due to the low thermal efficiency of the rotary dryer used in the "dry grinding and dry burning" process, although the amount of evaporated water is less than that of the "wet grinding and dry burning" process, the heat consumption of the two is equivalent. In addition, calcium carbide slag rolls forward in the rotary dryer and gradually becomes dense. It needs to be re-grinded to make raw meal. It is suspected of violating the process route just like "wet grinding and dry burning" by adding water and then dehydrating, and it also causes The power consumption of the "dry grinding and dry burning" process is slightly higher.

The raw material for calcium carbide production is high-quality lime, which contains trace elements such as potassium, sodium, magnesium, phosphorus, and sulfur. Under the condition that the temperature in the calcium carbide furnace is as high as 2000 ℃ and the reducing atmosphere, the MgO of the raw material is reduced to a simple substance, and escapes after being gasified together with K ₂ O and Na ₂ O; phosphorus and sulfur are combined with calcium and are hydrolyzed by calcium carbide. Generate PH ₃ and H ₂ S gas out of the system; in the process of hydrolyzing calcium carbide to obtain acetylene gas, calcium only appears as a carrier and is not consumed before and after the reaction. Due to the above reasons, Ca(OH) ₂ in carbide slag is relatively pure, and the clay raw materials with high silicon content are required in batching, and clay raw materials with high silicon content often have high crystalline silicon content, resulting in poor grindability of the material.

In the "dry grinding and dry burning" process, the vertical mill is used to dry and grind the batch materials. Because the vertical mill has a strong drying capacity, only the vertical mill can grind raw materials with a comprehensive moisture of about 12%, but the raw materials are easy to grind. When the abrasiveness is poor, it is often not recommended to use a vertical mill. The contradiction between drying capacity and grinding capacity makes the use of vertical mills in the "dry grinding and dry burning" process very embarrassing.

In the above two processes, except for the first method of "wet grinding and dry burning", which is the method of using a crushing dryer to dry the raw material filter cake, the materials in the other methods all have the process of heating, cooling, and heating again, so There is unnecessary heat loss.

Calcium carbide slag itself has fine particles and can be used in cement production without grinding. It is viscous after being pressed into a filter cake, but basically has no strength. When drying slowly, the surface is easy to form a hard shell, but it will produce a certain strength and needs to be re-grinded. However, under the condition of rapid drying, due to the generation of internal water vapor, the volume expands and produces internal stress, and the filter cake will naturally Disintegrates, has no strength.

According to the XRD measurement results of materials in the cones of preheaters at various levels in a traditional process in a factory, the calcium carbide slag in the raw meal has been decomposed at the cones of the first-stage cylinder, and the decomposition product CaO has to be preheated in multiple stages before reaching the rotary kiln. The temperature of the device continues to rise, resulting in dead burning. At this time, the decomposition of clay minerals has not yet been completed. The occurrence of this phenomenon leads to an increase in activation energy, which is not conducive to the early solid phase reaction.

Utility model content:

The purpose of the utility model is to make up for the defects of the prior art, and provide a cement-making device using calcium carbide slag, which is used for clinker calcination and can reduce the heat consumption and power consumption of clinker production.

The utility model is achieved through the following technical solutions:

A device for making cement using carbide slag, characterized in that:

Including kiln tail smoke chamber, rotary kiln, preheater and calciner;

The calciner includes a vertical furnace body, and the furnace body is divided into zone Ⅰ and zone Ⅱ from top to bottom; the furnace body in zone Ⅰ and zone Ⅱ are equipped with pulverized coal nozzles;

The top of the furnace body in zone Ⅰ is provided with an air outlet and a calcium carbide slag filter cake inlet, and the air outlet leads to the feed inlet of the preheater. The furnace body in zone Ⅰ is equipped with a dispersing device and an air ring, and the air ring is located below the dispersing device;

There are auxiliary raw material inlets on the side wall of the furnace body in Zone II. There are tertiary air pipes connected to the furnace body in Zone II. There is a smoke chamber shrink at the bottom of the furnace body in Zone II. The outlet of the chamber leads to the rotary kiln;

An air lock valve is installed between the discharge port of the preheater and the feed port of the kiln tail smoke chamber.

The device for making cement by using calcium carbide slag is characterized in that: the furnace body is covered with a support and connected to the floor through the support.

The device for making cement by using calcium carbide slag is characterized in that: the furnace body in zone I and the furnace body in zone II both include a cone part and a straight cylinder part; the furnace body in the cone part includes a conical outer shell , the inner wall of the conical outer shell is welded with nails and then masonry refractory castables; the straight cylindrical part of the furnace body includes a straight cylindrical outer shell, and the inner wall of the straight cylindrical outer shell is bonded with silicon-calcium boards and then built with refractory bricks; the cone The gap between the part and the straight cylinder part is plugged with a burnt-out gasket.

At present, when using wet-discharged carbide slag to make cement, the traditional cement process is still followed. The wet-discharged carbide slag is dehydrated, dried and made into raw meal, and then heated in the preheater and decomposed in the calciner. , and finally calcined into cement clinker in the rotary kiln. The utility model researches and develops a special calciner for the characteristics of wet discharge of calcium carbide slag. Dispersion devices and air rings are arranged in the calciner. The calcium carbide slag does not go through the process of making raw meal, and the preheating and decomposition of calcium carbide slag are in the calciner. One step is completed, after being mixed with auxiliary raw materials entering the calciner, it is collected by the preheater and put into the rotary kiln to be calcined into cement clinker. The utility model changes the traditional cement production method aiming at the physical and chemical properties of carbide slag.

Aiming at the problems existing in the traditional process of carbide slag cement production and the characteristics of wet discharge carbide slag, the utility model simplifies the cement production process and uses a calciner for clinker calcination, which can reduce the heat consumption and power consumption of clinker production The moisture content of the dry-discharged carbide slag is below 10%, and the calciner in the utility model is also applicable to the cement production of the dry-discharged carbide slag after removing the dispersing device.

The utility model has the advantages of:

The cement production method in the utility model is simpler than the traditional process, which reduces the construction investment of the carbide slag cement production line; since the carbide slag does not go through the process of making raw materials, there is no grinding power consumption, which can save power consumption; There is no process of heating, cooling, and heating again in the production, which reduces unnecessary heat loss and saves heat consumption; after the calcium carbide slag completes the preheating and decomposition process in the calciner, it is directly calcined in the rotary kiln, eliminating the phenomenon of dead burning. Can save heat consumption.

Description of drawings:

Fig. 1 is the structural representation of the utility model.

Figure 2 is a structural diagram of zone I of the calciner.

Figure 3 is a structural diagram of zone II of the calciner.

Fig. 4 is the section A-A of Fig. 2 .

Fig. 5 is a B-B section of Fig. 2 .

FIG. 6 is a C-C section of FIG. 3 .

FIG. 7 is a partial enlarged view of D in FIG. 2 .

Description of the serial numbers in the attached drawings: 1 - air outlet; 2 - carbide slag filter cake inlet; 3 - dispersion device; 4 - air ring; 5 - pulverized coal nozzle; Air pipe; 9-shrinkage of smoke chamber; 10-rotary kiln; 11-kiln tail smoke chamber; 12-air lock valve; 13-preheater; 17-calcium-silicon board; 18-refractory brick.

Detailed ways:

See attached picture.

A device for making cement by using calcium carbide slag, including a kiln tail smoke chamber 11, a rotary kiln 10, a preheater 13 and a calciner.

The calciner includes a vertical furnace body, and the furnace body is divided into zone I and zone II from top to bottom; the furnace body in zone I and the furnace body in zone II are equipped with pulverized coal nozzles 4; the top of the furnace body in zone I is equipped with an air outlet 1 And calcium carbide slag filter cake inlet 2, air outlet 1 leads to the feed inlet of preheater 13, dispersing device 3 and air ring 4 are arranged in the furnace body of zone I, and the air ring 4 is located below the dispersing device 3; the furnace body side of zone II There is an auxiliary raw material inlet 7 on the wall, a tertiary air duct 8 connected to the furnace body in zone II, a smoke chamber shrinkage 9 at the bottom of the furnace body in zone II, and the smoke chamber shrinkage 9 leads to the kiln tail smoke chamber 11, and the kiln tail smoke The discharge port of the chamber 11 leads to the rotary kiln 10; the air lock valve 12 is installed between the discharge port of the preheater 13 and the feed port of the kiln tail smoke chamber 11.

The body of the furnace is covered with a support 6 and is connected to the floor through the support 6 .

The furnace body in zone Ⅰ and zone Ⅱ both includes a cone part and a straight cylinder part; the furnace body in the cone part includes a conical outer shell, and the inner wall of the conical outer shell is welded with stainless steel nails 14 and then masonry refractory Castable 15; the straight cylinder part of the furnace body includes a straight cylinder outer shell, and the inner wall of the straight cylinder outer shell is bonded with silicon-calcium board 17 and then built with refractory bricks 18; the gap between the cone part and the straight cylinder part is used as a burnt-out gasket 10 plugs.

The dispersing device 3 and the air ring 4 are both made of heat-resistant steel with good temperature resistance and can work at a temperature of 900-950°C for a long time. Since there are no moving parts in the calciner, the failure rate of the calciner equipment is low. The connection part between the furnace body and the kiln tail smoke chamber 11 in zone II is built with a refractory castable 15 to form a smoke chamber shrinkage 9, and a "spray" effect is produced when the airflow passes through. Both the furnace body in zone I and zone II are equipped with pulverized coal nozzles 5, and the pulverized coal is burned by the fresh hot air introduced by the tertiary air duct 8. During production, the temperature in zone I is controlled at about 750°C, and the temperature in zone II is around 900°C .

During production, the calcium carbide slag filter cake with a moisture content of about 35% is fed from the inlet 2 of the carbide slag filter cake on the top of the furnace body in zone I, and the air can be locked by the three-way hydraulically driven valve. Carbide slag is a light waste residue that is easy to suspend. The calcium carbide slag filter cake falls on the dispersing device 3 and is broken up immediately. The broken up material rises with the airflow after being dried; The "effect" delays the falling speed of the material, and during this period, some materials are dried; in the end, the materials that still remain blocky fall into the II area, and when passing through the smoke chamber shrinkage 9, the "spray" produced by the smoke chamber shrinkage 9 is used. "Teng" effect, the lumpy materials collide with each other and are crushed, and then rise with the airflow.

Auxiliary raw materials composed of silicon-aluminum calibration materials, supplementary calcium raw materials, iron powder, etc. are fed from the auxiliary raw material inlet 7 on the furnace body of zone II after being heated up by preheaters at all levels, and most of them are decomposed in the decomposition furnace , together with calcium carbide slag rises with the airflow, enters the preheater 13 after passing through the airflow outlet 1, and falls into the rotary kiln 10 through the air lock valve 12 after being collected, completing the calcination process of cement clinker.

The decomposition temperature of calcium carbide slag is about 575°C, and the working temperature of the decomposition furnace is above 750°C. A large temperature difference is adopted to overlap the drying and decomposition processes of carbide slag, which can improve thermal efficiency and prevent internal water in carbide slag. Wet the part that has been dried repeatedly, and make full use of the stress caused by the phase change of moisture.

The thermal capacity of the decomposition furnace is much larger than that of the crushing dryer and rotary dryer: if the decomposition process of calcium carbide slag is to be completed, the air volume of the crushing dryer is sufficient, but the air temperature is not high; the air temperature of the rotary dryer is high but The air volume is not enough. The utility model absorbs some advantages of the crushing dryer and the vertical mill, and overcomes their shortcomings. The utility model has no moving parts, and has high reliability, and the material is dried in a suspended state, and the thermal efficiency is high. In the utility model, the preheating and decomposition of carbide slag are completed in one step in the calciner, and then collected into the rotary kiln for calcination. The new ecological CaO has better reactivity, which can reduce the heat consumption of clinker firing.

The conical outer shell and the straight cylindrical outer shell of the calciner are welded by steel plates with a thickness of 8mm; the calciner body is connected to the floor with a support 6; the cone part is welded with stainless steel on the inner wall of the conical outer shell Nails 14 with a spacing of 200mm. After the formwork is supported, refractory castables 15 are built and compacted with a vibrating rod. The thickness of the lower cone refractory castables 15 is 250mm, and the thickness of the upper cone refractory castables 15 is 200mm. Use a grinding wheel to grind away the corners and corners of the mould; the straight cylinder part is first bonded with a silicon-calcium board 17 on the inner wall of the straight cylinder-shaped outer shell, with a thickness of 100mm, and then build refractory bricks 18; reserve 10mm for the contact part between the cone and the straight cylinder, and burn Gasket 16 is plugged tightly; the dispersing device 3 and the air ring 4 are welded to the contact part of the cylinder body, and when the refractory brick 18 is built, there is less than one refractory brick 18 around the space, and then welding nails 14 are added and then filled with castable 15; the calciner After the masonry is completed, it can be put into use after being baked.

Claims (3)

1. A device utilizing carbide slag to make cement, characterized in that: Including kiln tail smoke chamber, rotary kiln, preheater and calciner; The calciner includes a vertical furnace body, and the furnace body is divided into zone Ⅰ and zone Ⅱ from top to bottom; the furnace body in zone Ⅰ and zone Ⅱ are equipped with pulverized coal nozzles; The top of the furnace body in zone Ⅰ is provided with an air outlet and a calcium carbide slag filter cake inlet, and the air outlet leads to the feed inlet of the preheater. The furnace body in zone Ⅰ is equipped with a dispersing device and an air ring, and the air ring is located below the dispersing device; There are auxiliary raw material inlets on the side wall of the furnace body in Zone II. There are tertiary air pipes connected to the furnace body in Zone II. There is a smoke chamber shrink at the bottom of the furnace body in Zone II. The outlet of the chamber leads to the rotary kiln; An air lock valve is installed between the discharge port of the preheater and the feed port of the kiln tail smoke chamber. 2. A device for making cement by utilizing calcium carbide slag according to claim 1, characterized in that: the furnace body is covered with a support and connected to the floor through the support. 3. A device for making cement using calcium carbide slag according to claim 1, characterized in that: the furnace body in zone I and the furnace body in zone II both include a cone part and a straight cylinder part; the furnace body in the cone part It includes a conical outer shell, and the inner wall of the conical outer shell is welded with nails and then masonry refractory castables; the straight cylinder part of the furnace body includes a straight cylindrical outer shell, and the inner wall of the straight cylindrical outer shell is bonded with silicon-calcium boards. Build refractory bricks; the gap between the cone part and the straight cylinder part is filled with burnt gaskets.

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