CN210752064U - Calcium circulation semi-dry desulfurization system for cement clinker production line - Google Patents
Calcium circulation semi-dry desulfurization system for cement clinker production line Download PDFInfo
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- CN210752064U CN210752064U CN201920859881.0U CN201920859881U CN210752064U CN 210752064 U CN210752064 U CN 210752064U CN 201920859881 U CN201920859881 U CN 201920859881U CN 210752064 U CN210752064 U CN 210752064U
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Abstract
The utility model discloses a cement clinker production line calcium circulation semidry desulfurization system, belonging to the technical field of flue gas desulfurization, which comprises a decomposition unit, a desulfurization unit and a dust collection unit; the desulfurizer preparation unit comprises a cooling unit connected with a discharge port of the decomposition unit and a digestion unit connected with a discharge port of the cooling unit; the discharge port of the digestion unit is connected with the feed port of the desulfurization unit, and the desulfurization unit dischargesThe opening is connected with a feed inlet of a dust collection unit, and a discharge outlet of the dust collection unit is connected with a decomposing furnace through a desulfurized slag conveying unit. The system adopts self-made active heat raw materials to prepare a desulfurizer through cooling by a cooling unit and digestion by a digestion unit, then the desulfurizer is fed into a desulfurization unit for desulfurization, and the generated desulfurization slag returns to a decomposing furnace to enter a rotary kiln for calcination. The utility model realizes self-sufficiency of the desulfurizer and solves the problem of flue gas SO2The discharge problem is solved, the cost of externally purchased desulfurizer is saved, and the problem of treatment of the semi-dry desulphurization slag is solved.
Description
Technical Field
The utility model relates to a flue gas desulfurization technical field especially relates to a cement clinker production line calcium circulation semidry process desulfurization system.
Background
The cement raw materials mainly comprise calcium raw materials, silicon-aluminum raw materials, iron raw materials and the like, wherein the calcium raw materials are mainly used and generally account for about 80 percent. In the production process of cement clinker, when the raw material contains more low-valence sulfur such as organic sulfur or sulfide, the low-valence sulfur is released to generate SO by high-temperature oxidation in the preheater2Gas, resulting in SO in the flue gas2The concentration exceeds the standard, and the environmental-friendly emission index can be reached only by carrying out desulfurization treatment.
The existing cement kiln flue gas desulfurization methods mainly comprise dry desulfurization, wet desulfurization and the like, and the desulfurizing agent is mainly purchased from the outside. The desulfurizer adopted by dry desulfurization is calcium hydroxide or sodium bicarbonate and the like, and is fed to the positions of an air duct of a preheater at the tail of a kiln and the like, and the desulfurizer reacts with sulfur dioxide in flue gas to perform desulfurization, but the desulfurization efficiency is often lower, and the method is not suitable for cement production lines with high sulfur dioxide background concentration.
The cement kiln flue gas can also adopt a wet desulphurization process, wherein the most common wet desulphurization method is a lime/gypsum method, namely limestone is adopted as a desulfurizer, the limestone is mixed with water to prepare slurry, the slurry is sprayed into a desulphurization tower, and the lime slurry absorbs sulfur dioxide in the flue gas to react to generate gypsum. Wet desulfurization has the problems of white smoke, gypsum rain, chimney corrosion and the like, and has large water consumption, the wastewater needs to be treated, and the whole treatment cost is higher.
Compared with wet desulphurization, the flue gas semi-dry desulphurization technology has the advantages of clean smoke traces, no white smoke, no gypsum rain, low water consumption, no wastewater treatment, small corrosion to chimneys and the like, and is the development direction of the flue gas desulphurization technology at home and abroad. The existing semi-dry desulfurization technology needs an external desulfurizer (quicklime or hydrated lime), the cost of the desulfurizer is high, the desulfurized slag is difficult to dispose, and the technology has no engineering application in the cement industry. The technical principle of the semi-dry desulfurization method is as follows: SO in flue gas2And the desulfurizing agent and water in the circulating fluidized bed desulfurizing tower are subjected to ionic chemical reaction to generate desulfurization products such as calcium sulfite and the like. The desulfurizer is highly enriched under the external circulation system of the dust collector to realize SO in the flue gas2The removal is efficient.
The main reaction formula is as follows:
CaO+H2O→Ca(OH)2
Ca(OH)2+SO2→CaSO3·1/2H2O+1/2H2O
the flue gas semi-dry desulfurization technology generates a large amount of desulfurization byproducts (also called desulfurization ash) which are difficult to comprehensively utilize due to complex components and a large amount of calcium sulfite. The desulfurized ash is characterized by a large amount of unoxidized CaSO3(mainly present in the form of CaSO)3·1/2H2O)。
At present, one treatment mode of semi-dry desulfurization ash is to treat CaSO in the desulfurization ash3Oxidation to CaSO4And the activity of the desulfurized ash is improved, so that the desulfurized ash can be used for cement retarders or mixing materials. The existing method for oxidizing semi-dry desulfurization ash mainly adopts high-temperature air oxidation and low-temperature wet catalytic oxidation. The oxidation temperature corresponding to the high-temperature air oxidation method is generally higher than 500 ℃, the energy consumption in the disposal process is high, and the disposal cost is high; the low temperature wet catalytic oxidation method not only increases the cost of the oxidation process, but also has SO if the regulation is not good2Potential risk of secondary escape. The other semi-dry desulfurization ash disposal mode is stacking or abandoning disposal, which wastes land resources and sulfur resources and generates secondary pollution.
In summary, the problems of the prior art are as follows:
(1) the cement kiln flue gas desulfurization adopts dry desulfurization or wet desulfurization, which has the defects that the desulfurization efficiency is low, and the wet desulfurization has the problems of gypsum rain, white smoke emission, water consumption, wastewater treatment and the like.
(2) The cement kiln flue gas desulfurization adopts a semidry desulfurization technology, and needs to purchase an external quick lime or slaked lime desulfurizer, so that carbonization can occur in the transportation and storage processes, lime is converted into calcium carbonate, and the activity of the desulfurizer is reduced.
(3) The cement kiln flue gas desulfurization adopts a semidry desulfurization technology, quicklime or hydrated lime is adopted as a desulfurizer for flue gas desulfurization and needs to be purchased, the operation cost of a desulfurization system is high, and meanwhile, the process of preparing lime by using the lime kiln also consumes energy, generates air pollution and consumes limestone mineral resources.
(4) The cement kiln flue gas desulfurization adopts a semi-dry desulfurization technology, and the main component of the generated desulfurization slag is calcium sulfite, so that the resource utilization and the disposal are difficult.
The difficulty and significance for solving the technical problems are as follows: the semi-dry desulfurization technology is a development direction of the flue gas desulfurization technology due to the high desulfurization efficiency and the absence of white smoke, gypsum rain and other problems. The cement clinker production line calcium circulation semidry desulfurization system provides the desulfurizer prepared by the production line for the semidry desulfurization system, and the desulfurization slag is cooperatively treated, so that the cement kiln flue gas desulfurization system has important significance for popularization and application of the cement kiln flue gas desulfurization technology with high efficiency, low cost and no waste slag.
Disclosure of Invention
An object of the utility model is to provide a cement clinker production line calcium circulation semidry desulfurization system, this system will be through the thermal raw material of decomposing of dore furnace, through corresponding cooling, in the half dry desulfurization unit of the back feeding flue gas of digestion, absorb the sulfur dioxide that produces in the cement kiln clinker production process, desulfurization efficiency is high, saves the cost of purchasing the desulfurizer outward, reduces lime ore resource consumption. And simultaneously, the desulfurized slag is returned to a kiln system for resource utilization, so that the problem of treatment of the desulfurized slag by a semidry method is solved.
The utility model discloses a realize like this, a cement clinker production line calcium circulation semidry process desulfurization system, include with the decomposition unit of raw material decomposition system active hot raw material, absorb SO in the flue gas2The decomposition unit comprises a multi-stage kiln tail preheater and a decomposition furnace; the desulfurizer preparation unit comprises a cooling unit connected with a discharge port of the decomposition unit and a digestion unit connected with a discharge port of the cooling unit; the discharge gate and the desulfurization unit feed inlet of digestion unit are connected, the desulfurization unit discharge gate is connected with the unit feed inlet that gathers dust, the unit discharge gate that gathers dust is through desulfurization sediment conveying unit connection dore furnace.
Preferably, the cooling unit is two-stage suspension cooling; the cooling unit comprises a first-stage cyclone cylinder and a second-stage cyclone cylinder, an outlet air pipe of the first-stage cyclone cylinder is connected with an inlet of the second-stage cyclone cylinder, a discharge pipe of the second-stage cyclone cylinder is connected with the inlet of the first-stage cyclone cylinder, cooling air is introduced into the inlet of the first-stage cyclone cylinder, and the outlet air pipe of the second-stage cyclone cylinder is connected with a waste gas treatment system through a fan.
Preferably, the cooling unit is connected with a cyclone discharge pipe of the last-stage kiln tail preheater through a material taking unit, the material taking unit comprises a material separating pipe, a high-temperature gate valve I and a high-temperature rotary discharger, the high-temperature gate valve I is arranged on the material separating pipe, one end of the material separating pipe is connected with the cyclone discharge pipe of the last-stage kiln tail preheater, and the other end of the material separating pipe is connected with an outlet air pipe of the first-stage cyclone.
The second-stage cyclone blanking pipe is also connected with a material distribution pipe positioned at the upper part of the high-temperature gate valve, and a material distribution valve is arranged at the branch of the second-stage cyclone blanking pipe.
Preferably, the cooling unit is connected with an outlet air pipe of the decomposing furnace through a material taking unit; the material taking unit comprises a material taking cyclone, a high-temperature gate valve II is arranged on an inlet pipeline of the material taking cyclone, and a high-temperature gate valve III is arranged on an outlet air pipe of the material taking cyclone; the inlet pipeline of the material taking cyclone is connected with an outlet air pipe of the decomposing furnace, the outlet air pipe of the material taking cyclone is connected with an outlet air pipe of a last-stage or penultimate kiln tail preheater, and the discharging pipe of the material taking cyclone is connected with an outlet air pipe of a first-stage cyclone.
Further preferably, the feed opening of the first-stage cyclone is connected with a material collecting bin, a discharge opening of the material collecting bin is provided with a first gate valve and a screw feeder with a meter, and an outlet of the screw feeder with the meter is connected with the digestion unit.
Preferably, the digestion mode of the digestion unit is dry digestion, and an exhaust port of the digestion unit is connected with a cement kiln flue gas and waste gas treatment system through an air pipe of the cooling unit.
The digestion unit is also provided with a quicklime feeding port.
Preferably, the desulfurization unit comprises an air inlet pipeline arranged at the lower part of the desulfurization unit, an absorption tower arranged at the upper part of the desulfurization unit, and a venturi tube which is positioned between the air inlet pipeline and the absorption tower and is connected with the air inlet pipeline and the absorption tower; a water spraying device is arranged in the absorption tower; and the discharge hole of the digestion unit is connected with an air inlet pipeline or an absorption tower of the desulfurization unit.
The desulfurization unit is also provided with a hydrated lime charging hole.
Preferably, the desulphurization slag conveying unit comprises a Roots blower, a heater and a storage bin which are sequentially connected through a conveying pipeline, a discharge hole of the storage bin is provided with a gate valve II and an air locking member, the desulphurization slag discharged by the air locking member is fed into a column section above a tertiary air pipe of the decomposing furnace, and a dust collector is arranged above the storage bin.
A desulfurized slag bin is arranged between the dust collection unit and the desulfurized slag conveying unit, a gate valve III and a rotary feeder are arranged at a discharge port of the desulfurized slag bin, and an outlet of the rotary feeder is connected with a conveying pipeline between the heater and the storage bin.
Further preferably, the conveying pipeline and the storage bin of the desulphurization slag conveying unit are both provided with an external heat-insulating layer.
Preferably, the discharge hole of the dust collection unit is connected with an air inlet pipeline of the desulfurization unit; the dust collection unit is also provided with an external discharge disposal pipeline which is connected with a raw material warehouse or a kiln tail preheater.
The utility model has the advantages of it is following and beneficial effect:
1. the utility model discloses utilize the cement kiln to have the active characteristics of high desulfurization through the hot raw material of dore decomposition, establish cement clinker production line calcium circulation semidry process desulfurization system, adopt the cement kiln from heating the raw material, cool off the high temperature material earlier, carry out the digestion increase to the material again, can make the digestibility of calcium oxide in the material reach more than 90%, in order to prepare high activity desulfurizer, realize that the desulfurizer is self-sufficient, thereby partly or whole substitute the outsourcing desulfurizer, solve the flue gas sulfur dioxide emission problem, save the cost of outsourcing desulfurizer, reduce lime ore resource consumption;
2. the utility model discloses a semidry desulfurization sediment adopts and deals with in the desulfurization sediment feeding decomposing furnace, and the high temperature aerobic environment who utilizes the decomposing furnace is greater than 800 ℃ and oxidizes calcium sulfite into calcium sulfate, utilizes the cement raw material to produce a large amount of calcium oxide absorption semidry desulfurization sediment pyrolysis production SO in the decomposing furnace after calcining simultaneously2Effectively solves the problem of SO possibly occurring in the treatment process of the semi-dry desulphurization slag2The problem of secondary escape;
3. the utility model discloses a production of normal production line is not influenced in the operation of calcium circulation semidry desulfurization system, and manufacturing cost and running cost are low, convenient operation, no waste water treatment, desulfurization efficiency height.
Drawings
Fig. 1 is a flow chart of a system according to an embodiment of the present invention;
FIG. 2 is a flow chart of the cooling and digestion provided by the first embodiment of the present invention by taking the material from the cyclone discharge pipe of the last stage kiln tail preheater;
FIG. 3 is a flow chart of the desulfurizing slag conveying unit according to the first embodiment of the present invention;
FIG. 4 is a first flow chart of the cooling and digestion by taking the material from the outlet air duct of the decomposing furnace according to the second embodiment of the present invention;
FIG. 5 is a second flow chart of the cooling and digestion by taking the material from the outlet air duct of the decomposing furnace according to the second embodiment of the present invention;
fig. 6 is a flowchart of a system according to a third embodiment of the present invention;
fig. 7 is a flowchart of a system according to a fourth embodiment of the present invention;
fig. 8 is a flowchart of a system according to a fifth embodiment of the present invention.
In the figure: 10-a decomposition unit; 101-a decomposing furnace; 1011-tertiary air duct; 102-cyclone of last stage kiln tail preheater; 103-a cyclone of a penultimate kiln tail preheater; 104-cyclone of last but one stage kiln tail preheater;
20-a cooling unit; 201-first stage cyclone cylinder; 202-second stage cyclone; 203-a fan; 204-an exhaust gas treatment system; 205-a distributing valve; 206-aggregate bin; 207-a gate valve I; 208-a screw feeder with a meter;
30-a digestion unit; 301-quicklime feed inlet;
40-a desulfurization unit; 401-an air intake duct; 402-an absorption column; 403-a venturi tube; 404-a water spraying device; 405-a slaked lime feed port;
50-a dust collecting unit;
601-material distributing pipe; 602-high temperature gate valve I; 603-high temperature rotary discharger; 604-a take off cyclone; 605-high temperature gate valve II; 606-high temperature gate valve III;
70-a rotary kiln;
80-a desulfurizing slag conveying unit; 801-Roots blower; 802-a heater; 803-a storage bin; 804-a gate valve II; 805-rotary feeder; 806-a dust collector; 810-a desulfurized slag bin; 811-gate valve iii; 812-rotary feeder.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the following embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1
Referring to fig. 1, an embodiment of the present invention provides a calcium circulation semi-dry desulfurization system for a cement clinker production line, which includes a decomposition unit 10 for decomposing raw materials into active hot raw materials, and a flue gas absorption unit for absorbing SO in flue gas2The desulfurization unit 40 and the dust collection unit 50 for collecting desulfurized slag, wherein the decomposition unit 10 comprises a multi-stage kiln tail preheater and a decomposition furnace 101, the kiln tail preheater is a three-to seven-stage kiln tail preheater, and a five-stage preheater is preferably adopted in the embodiment; the desulfurizer preparation unit is connected with the decomposition unit 10 and the desulfurization unit 40, and is used for preparing desulfurizer by cooling and digesting partial hot raw materials decomposed by the decomposition unit, and comprises a cooling unit 20 connected with a discharge port of the decomposition unit 10 and a digestion unit 30 connected with a discharge port of the cooling unit 20; the discharge hole of the digestion unit 30 is connected with the feed inlet of the desulfurization unit 40, the discharge hole of the desulfurization unit 40 is connected with the feed inlet of the dust collection unit 50, and the discharge hole of the dust collection unit 50 is connected with the decomposing furnace 101 through the desulfurized slag conveying unit 80. The working principle of the technical scheme is as follows: decomposing the raw material at high temperature by a decomposition unit 10 to obtain active raw material, cooling the collected active raw material from 800-950 ℃ to within 150 ℃ by a cooling unit 20, digesting the cooled active raw material by a digestion unit 30, reacting calcium oxide to generate calcium hydroxide, feeding the digested active raw material into a flue gas semi-dry desulfurization unit 40, and absorbing SO in flue gas in the desulfurization unit by the digested active raw material as a desulfurizing agent2The desulfurized slag in the desulfurization unit 40 enters the dust collection unit along with the flue gas50, the desulfurized slag collected by the dust collection unit 50 is fed into the decomposing furnace 101 through a desulfurized slag conveying unit, and the desulfurized slag is calcined in the decomposing furnace 101, finally enters the rotary kiln 70 and is solidified into the discharged clinker, so that the synergistic on-line treatment of the desulfurized slag is realized. In general, the desulfurizer is prepared by cooling and digesting the cement kiln self-heating raw materials and absorbing sulfur dioxide generated in the cement kiln clinker production process, so that the externally purchased desulfurizer is partially or completely replaced, the cost of the externally purchased desulfurizer is saved, and the resource consumption of lime ore is reduced. The problem of emission of sulfur dioxide in flue gas is solved by utilizing the characteristics of the kiln system, the desulfurization slag is treated by the kiln system, no wastewater is treated, and the desulfurization efficiency is high.
The cooling means of the cooling unit 20 is air cooling to lower the temperature of the high temperature active raw meal taken out from the decomposition unit.
In order to ensure that the taken high-temperature active raw material can be cooled to the required temperature, an air-cooled cooling unit is adopted for two-stage suspension cooling.
Referring to fig. 2, the cooling unit 20 includes a first stage cyclone 201 and a second stage cyclone 202, an outlet air duct of the first stage cyclone is connected to an inlet of the second stage cyclone 202, a discharge duct of the second stage cyclone 202 is connected to an inlet of the first stage cyclone 201, cooling air is introduced into the inlet of the first stage cyclone 201, and an outlet air duct of the second stage cyclone 202 is connected to an exhaust gas treatment system 204 through a fan 203. The working principle of the technical scheme is as follows: the high-temperature active raw material enters the outlet air pipe of the first-stage cyclone 201 and then enters the second-stage cyclone 202, most of the active raw material is collected under the separation action of the second-stage cyclone 202, and the second-stage cyclone 202 preferably adopts a cyclone with the separation efficiency of more than 90%. The temperature of the active raw material collected from the second-stage cyclone 202 is 300-600 ℃, the active raw material is mixed with cooling air and enters the first-stage cyclone 201, the first-stage cyclone preferably adopts a cyclone with the separation efficiency of more than 80%, and the temperature of the active raw material separated by the first-stage cyclone 201 is reduced to below 150 ℃. Under the induced air of the fan 203, the cooling air firstly passes through the first-stage cyclone 201 from bottom to top and then passes through the second-stage cyclone 202, the dust-containing air which is discharged from the second-stage cyclone 202 enters the cement kiln flue gas and waste gas treatment system 204 after passing through the fan 203, and the waste gas treatment system 204 adopts the existing waste gas treatment device, such as a bag-type dust collector. The high-temperature active raw material can be cooled to below 150 ℃ after being subjected to two-stage suspension cooling, the feasibility of a scheme for directly taking the high-temperature active raw material is realized, and the cooling efficiency is high.
The cooling unit 20 is connected with a discharge pipe of a cyclone 102 of the last-stage kiln tail preheater through a material taking unit. After the raw meal is calcined in the decomposing furnace 101, calcium carbonate in the raw meal is decomposed at high temperature into calcium oxide, and the high-temperature calcined raw meal is referred to as active raw meal. The active raw materials enter the cyclone 102 of the last-stage kiln tail preheater along with the flue gas, gas-solid separation is carried out through the cyclone 102 of the last-stage kiln tail preheater, most of the active raw materials are collected, and a small part of the active raw materials exit the cyclone 102 of the last-stage kiln tail preheater along with the flue gas and enter the last-stage kiln tail preheater. A portion of the active raw material collected by the cyclone 102 of the final kiln tail preheater enters the cooling unit 20 through the take-off unit for cooling and another portion returns to the rotary kiln 70. Active raw materials subjected to gas-solid separation by the cyclone 102 of the last-stage kiln tail preheater are easier to collect, and the material taking unit is convenient to take materials.
Referring to fig. 2, the material taking unit includes a material distributing pipe 601, a high-temperature gate valve i 602 and a high-temperature rotary discharger 603, the high-temperature gate valve i is disposed on the material distributing pipe, one end of the material distributing pipe 601 is connected to a material discharging pipe of a cyclone 102 of a last-stage kiln tail preheater, and the other end is connected to an outlet air duct of a first-stage cyclone 201 of the cooling unit 20. When the material needs to be taken, the high-temperature gate valve I602 is opened, the amount of the high-temperature active raw material taken out from the material-taking pipe of the cyclone 102 of the last-stage kiln tail preheater can be regulated and controlled by controlling the rotating speed of the high-temperature rotary discharger 603, and the taken-out high-temperature active raw material is sent to the outlet air pipe of the first-stage cyclone 201 of the cooling unit 20. The material taking amount can be freely controlled according to the requirement, and the operation is simple and convenient.
The feeding pipe of the second-stage cyclone 202 is also connected with a material distribution pipe positioned at the upper part of the high-temperature gate valve I602, and the feeding pipe of the second-stage cyclone 202 is provided with a material distribution valve 205 at a branch position. The temperature of the active raw materials collected from the second-stage cyclone 202 is 300-600 ℃, the active raw materials are divided into two parts through the material dividing valve 205, one part of the active raw materials is mixed with the high-temperature active raw materials with the temperature of 800-950 ℃ in the material taking pipe 601, the temperature of the high-temperature active raw materials is reduced, the temperature of the mixed materials entering the high-temperature rotary discharger 603 is lower than 700 ℃, and therefore the requirement on high-temperature resistant materials of the high-temperature rotary discharger 603 is lowered. Mixing a part of the active raw material from the second stage cyclone 202 with the high temperature active raw material just taken out can reduce the temperature of the mixed material to be more than 700 ℃, thereby protecting the high temperature material rotary discharger.
Referring to fig. 2, a discharge port of the first stage cyclone 201 is connected to a collecting bin 206, a discharge port of the collecting bin 206 is provided with a first gate valve 207 and a screw feeder 208 with a meter, and an outlet of the screw feeder 208 with the meter is connected to the digestion unit 30. The cooled active raw materials are firstly fed into a material collecting bin 206 before digestion and synergism, and are fed into the digestion unit 30 after being measured by a screw feeder 208 with a meter, and the storage period of the material collecting bin 206 is less than 24 hours so as to avoid raw material hardening. The feeding speed and the feeding amount are controlled by the spiral feeder with the meter, and the operation is convenient.
The digestion mode of the digestion unit 30 is dry digestion. In practice, the digestion unit 30 may be implemented as an existing dry digester. By spraying water into the digestion unit 30, the calcium oxide in the material reacts with water to generate active calcium hydroxide, and the material exiting the digestion unit 30 is an active desulfurizer. The independent dry digester is adopted, so that the digestibility of calcium oxide can reach over 90 percent, and the activity of the prepared desulfurizer is higher.
Referring to fig. 2, the exhaust port of the digestion unit 30 is connected to a cement kiln flue gas and exhaust gas treatment system 204 through an air duct of the cooling unit 20. In specific implementation, the exhaust port of the digestion unit 30 may be connected to the outlet air duct of the first stage cyclone 201 of the cooling unit 20 through an exhaust duct, or may be connected to the outlet air duct of the second stage cyclone 202 of the cooling unit 20, and further connected to the flue gas and exhaust gas treatment system 204 of the cement kiln. The dust-containing water vapor out of the digestion unit 30 enters the two-stage suspension cooling unit 20 through the exhaust pipeline and finally enters the waste gas treatment system 204, and the dust-containing water vapor is purified through the waste gas treatment system 204, so that the atmospheric pollution is avoided. And a dust-containing water vapor purification treatment device is not required to be arranged independently, so that the investment and the operation cost are saved.
Referring to fig. 1, the desulfurization unit 40 includes an air inlet pipe 401 disposed at a lower portion of the desulfurization unit, an absorption tower 402 disposed at an upper portion of the desulfurization unit, and a venturi tube 403 disposed between and connected to the air inlet pipe and the absorption tower; a water spraying device 404 is arranged in the absorption tower 402. The absorption tower 402 in this embodiment adopts an existing structure, that is, includes a cylindrical portion and a conical portion from top to bottom, and the water spraying device 404 is located in the cylindrical portion or the conical portion of the absorption tower, so as to better absorb sulfur dioxide in the flue gas. The digested active raw material is fed into a flue gas inlet pipeline 401 of the desulfurization unit and is uniformly dispersed in the flue gas entering the desulfurization unit. The active raw materials and the flue gas enter the venturi tube 403 and the absorption tower 402 together, and the air speed in the venturi tube 403 is 20-50 m/s, so that the material collapse can be prevented. The water spraying device 404 is connected with the absorption tower 402, water is sprayed into the absorption tower 402, sulfur dioxide in the flue gas undergoes a chemical reaction under the combined action of water and the digested active raw materials, the sulfur dioxide in the flue gas is reduced, and simultaneously, the desulfurized slag mainly containing calcium sulfite is generated. The desulfurized flue gas meets the emission standard of sulfur dioxide.
The material outlet of the digestion unit 30 is connected to the gas inlet pipe 401 or the absorption tower 402 of the desulfurization unit. And the desulfurizer generated after being digested by the digestion unit 30 is sent to an air inlet pipeline 401 or an absorption tower 402 in the desulfurization unit for desulfurization.
The desulfurization slag conveying unit 80 adopts a pneumatic conveying mode or a mechanical conveying mode. The pneumatic conveying is preferably selected in the embodiment, the desulfuration residue conveying unit 80 is a pneumatic conveyor, the conveying efficiency is high, the labor productivity is greatly improved, the cost is reduced, and the stable conveying of the desulfuration residues is realized.
Referring to fig. 3, the desulfurization slag conveying unit 80 adopting pneumatic conveying comprises a roots blower 801, a heater 802 and a storage bin 803 which are connected in sequence through a conveying pipeline, a discharge port of the storage bin 803 is provided with a second gate valve 804 and an air locking member, an outlet of the air locking member is connected with the decomposing furnace 101, and a dust collector 806 is arranged above the storage bin 803. The air locking component is an existing rotary feeder or a flap air locking valve, and the rotary feeder 805 is selected in the embodiment. The air is heated by the heater 802 after exiting the Roots blower 801, and the heater 802 can be heated by an electric heater or high-temperature steam, and the temperature is raised to be higher than 80 ℃. Under the power of the Roots blower 801, air is used as a pneumatic conveying medium to convey the desulfurized slag discharged from the rotary feeder 812 of the desulfurized slag bin 810 into the desulfurized slag storage bin 803, the desulfurized slag is discharged from the storage bin 803 and fed into the decomposing furnace 101, the conveyed air does not enter the decomposing furnace 101, and the flue gas in the conveying process is discharged after being subjected to dust collection by the dust collector 806 on the storage bin 803. The discharge speed is controlled through the second gate valve 804 and the rotary feeder 805, and meanwhile, the rotary feeder 805 serves as an air locking component to prevent air conveying from entering the decomposing furnace 101, so that the stability of the working condition of the decomposing furnace is influenced, and the increase of heat consumption caused by the fact that the air conveying enters the decomposing furnace is reduced.
Referring to fig. 3, a desulfurized slag bin 810 is arranged between the dust collecting unit 50 and the desulfurized slag conveying unit 80, a gate valve III 811 and a rotary feeder 812 are arranged at a discharge port of the desulfurized slag bin 810, and an outlet of the rotary feeder 812 is connected with a conveying pipeline between the heater 802 and the storage bin 803. In consideration of preventing the dust-carrying gas from being discharged outside during the collection of the desulfurization slag, a dust collector can be arranged on the desulfurization slag bin 810. And a gate valve III 811 and a rotary feeder 812 are used for controlling the discharging speed of the desulfurized slag from the bottom of the desulfurized slag bin, and the discharged desulfurized slag is conveyed into a conveying pipeline between the heater 802 and the storage bin 803.
The desulfurized slag discharged from the rotary feeder 812 is fed into the column section part above the tertiary air pipe 1011 of the decomposing furnace 101. The desulfurized slag can also enter the decomposing furnace along with tertiary air of the tertiary air pipe. The desulfurized slag enters the decomposing furnace 101 and then undergoes a high-temperature oxidation reaction to ensure that calcium sulfite is oxidized at high temperature, calcium sulfite in the desulfurized slag is oxidized into calcium sulfate, and the oxidized desulfurized slag enters the rotary kiln 70 along with raw materials in the furnace to be calcined to form cement clinker.
The conveying pipeline and the storage bin 803 of the desulphurization slag conveying unit 80 are both provided with an external heat-insulating layer. The temperature of the semi-dry desulphurization slag before entering the furnace is controlled to be higher than 80 ℃, and the crystal water is prevented from being converted into free water, so that the desulphurization slag is sticky and hardened and blocks equipment.
Referring to fig. 1, the discharge port of the dust collecting unit 50 is connected to an air inlet pipe 401 of a desulfurization unit. The desulfurizing agent which is not completely reacted in the desulfurization slag is fed into the desulfurization unit again to continue the circulating desulfurization reaction, and the utilization rate of the desulfurizing agent is improved. The dust collecting unit 50 in this embodiment may be a bag type dust collector or an electric dust collector. One part of the desulfurized slag collected by the dust collection unit 50 is returned to the air inlet pipeline 401 of the desulfurization unit for circulation, and the other part is fed into the decomposing furnace 101 through the desulfurized slag conveying unit 80.
Generally, when a semi-dry desulfurization system is used, a small amount of self-prepared desulfurizer is needed, but the running power consumption of the desulfurization system is relatively high, and when a dry desulfurization system is adopted, a large amount of self-prepared desulfurizer is needed, but the system is simple and the running power consumption is low. Therefore, a semi-dry desulfurization system or a dry desulfurization system can be selected and used according to the comparison of the actual working condition, the preparation cost of the desulfurizer and the power consumption cost of the desulfurization system. When the sulfur content in the raw material is high, e.g. flue gas SO2Background concentration higher than 1500mg/Nm3In the meantime, the desulfurization efficiency of the dry desulfurization system is not enough to meet the environmental emission standard, and a semi-dry desulfurization system is required.
To sum up, the utility model discloses a cement kiln is in coordination with the processing technique and is established cement clinker production line calcium circulation semidry desulfurization system, adopt the hot raw meal of cement kiln self-control, in the active raw meal after cooling, digestion is as desulfurizer feeding flue gas semidry desulfurization unit, absorb the sulfur dioxide that produces in the cement kiln clinker production process, high desulfurization efficiency, utilize kiln system self characteristics to solve flue gas sulfur dioxide emission problem, thereby partly or whole substitute the outsourcing desulfurizer, save the cost of outsourcing desulfurizer, reduce lime ore resource consumption. The desulfurized slag is returned to the kiln system for resource utilization, and the problem of treatment of the desulfurized slag by the semidry method is solved.
Example 2
In contrast to example 1, the active hot raw meal is taken out of the outlet ductwork of the decomposing furnace 101.
Referring to fig. 4 and 5, the cooling unit 20 is connected to an outlet duct of the decomposing furnace 101 through a material taking unit. The active raw material out of the decomposing furnace enters the cyclone 102 of the last-stage kiln tail preheater along with most of the flue gas, and the rest enters the cooling unit 20 for cooling through the material taking unit.
The material taking unit comprises a material taking cyclone cylinder 604, a high-temperature gate valve II 605 is arranged on an inlet pipeline of the material taking cyclone cylinder 604, and a high-temperature gate valve III 606 is arranged on an outlet air pipe of the material taking cyclone cylinder 604; an inlet pipeline of the material taking cyclone 604 is connected with an outlet air pipe of the decomposing furnace 101, an outlet air pipe of the material taking cyclone 604 is connected with an outlet air pipe of a last-stage or a penultimate kiln tail preheater, and a discharging pipe of the material taking cyclone 604 is connected with an outlet air pipe of a first-stage cyclone 201 of the cooling unit 20.
When material is required to be taken, the material amount entering the material taking cyclone 604 is adjusted through the opening degrees of the high-temperature gate valve II 605 and the high-temperature gate valve III 606. The material taking amount can be freely controlled according to the requirement, and the operation is simple and convenient. Under the separating action of the material taking cyclone 604, the air out of the material taking cyclone 604 enters the inlet air pipe of the penultimate kiln tail preheater cyclone 103 or the penultimate kiln tail preheater cyclone 104, the high-temperature air returns to the heat exchange pipeline of the kiln tail preheater, most of heat is recovered, the influence on the energy consumption of the system is small, the material out of the material taking cyclone 604 enters the outlet air pipe of the first-stage cyclone 201 of the cooling unit 20, and the high-temperature active raw material taken out from the discharging pipe of the material taking cyclone 604 firstly enters the outlet air pipe of the first-stage cyclone 201, so that the taken high-temperature active raw material is fully cooled. FIG. 4 shows the entry of air out of the extraction cyclone 604 into the penultimate kiln tail preheater cyclone 103, and FIG. 5 shows the entry of air out of the extraction cyclone 604 into the penultimate kiln tail preheater cyclone 104.
Example 3
Unlike the embodiment 1 and the embodiment 2, referring to fig. 6, the desulfurization unit 40 is further provided with a hydrated lime feeding port 405. When equipment maintenance or system failure or SO in flue gas is carried out2When the concentration is high or the self-made desulfurizer of the active raw material cannot meet the desulfurization requirement, a certain amount of hydrated lime can be added into the desulfurizer entering the desulfurization unit 40 besides the self-made desulfurizer of the active raw material, so as to ensure that the desulfurization work is stably carried out and realize high-efficiency desulfurization.
Example 4
Different from the embodiments 1, 2 and 3, referring to fig. 7, the slaking unit 30 is further provided with a quicklime feeding port 301. When equipment maintenance or system failure or SO in flue gas is carried out2When the concentration is high or the self-made desulfurizer made of active raw materials cannot meet the self-sufficient desulfurization requirement of the system, a certain amount of quicklime can be added into the digestion unit 30 except for the active raw materials to ensure the amount of the generated desulfurizer, ensure the stable desulfurization work and realize high-efficiency desulfurization.
Example 5
Different from the embodiments 1, 2, 3, and 4, please refer to fig. 8, in which a discharge port of the dust collecting unit 50 is further provided with an external discharge disposal pipeline, and the external discharge disposal pipeline is connected to a raw material warehouse or a kiln tail preheater. The desulfurized slag can be returned to a desulfurization unit or fed into a decomposing furnace, can also be fed into a raw material warehouse or a preheater or discharged outside through conveying equipment, and is selected according to actual requirements, and the discharged desulfurized slag can be used as a backfill material for building roads or backfilling waste pits and the like.
To sum up, the utility model discloses cement clinker production line calcium circulation semidry process desulfurization system adopts the self-made hot raw meal of cement kiln, and active raw meal after cooling, digestion is as the desulfurizer, absorbs the sulfur dioxide that produces in the cement kiln clinker production process, reduces SO in the flue gas2The emission amount of the waste lime is reduced, so that the waste lime is partially or completely substituted for the purchased desulfurizer, the cost of the purchased desulfurizer is saved, the resource consumption of the lime mine is reduced, and meanwhile, the dust removal and purification treatment are carried out, so that the waste lime meets the environmental protection concept of protecting the environment and reducing the pollution. The desulfurized slag is returned to the kiln system for resource utilization, the problem of treatment of the desulfurized slag by the semidry method is solved, the method has the positive social effect of reducing the treatment and production cost of the industrial waste slag, the desulfurization effect is good and stable, and the operation cost is low.
Claims (10)
1. A calcium circulation semi-dry desulfurization system for a cement clinker production line comprises a decomposition unit (10) for decomposing raw materials into active hot raw materials and absorbing SO in flue gas2And a collection cycloneThe device comprises a dust collection unit (50) of the sulfur slag, wherein the decomposition unit (10) comprises a multi-stage kiln tail preheater and a decomposition furnace (101); the device is characterized by also comprising a desulfurizer preparation unit which is connected with the decomposition unit (10) and the desulfurization unit (40), wherein the desulfurizer preparation unit comprises a cooling unit (20) connected with a discharge port of the decomposition unit (10) and a digestion unit (30) connected with a discharge port of the cooling unit (20); the discharge gate and the desulfurization unit (40) feed inlet of digestion unit (30) are connected, desulfurization unit (40) discharge gate and dust collection unit (50) feed inlet are connected, dust collection unit (50) discharge gate passes through desulfurization sediment conveying unit (80) and connects dore furnace (101).
2. The cement clinker production line calcium circulation semi-dry desulfurization system of claim 1, wherein the cooling unit is a two-stage suspension cooling; the cooling unit (20) comprises a first-stage cyclone cylinder (201) and a second-stage cyclone cylinder (202), an outlet air pipe of the first-stage cyclone cylinder (201) is connected with an inlet of the second-stage cyclone cylinder (202), a blanking pipe of the second-stage cyclone cylinder (202) is connected with an inlet of the first-stage cyclone cylinder (201), cooling air is introduced into an inlet of the first-stage cyclone cylinder (201), and an outlet air pipe of the second-stage cyclone cylinder (202) is connected with an exhaust gas treatment system (204) through a fan (203).
3. The calcium circulation semi-dry desulphurization system of the cement clinker production line according to claim 2, wherein the cooling unit (20) is connected with a discharge pipe of a cyclone (102) of a final-stage kiln tail preheater through a material taking unit; the material taking unit comprises a material dividing pipe (601), a high-temperature gate valve I (602) and a high-temperature rotary discharger (603), wherein the high-temperature gate valve I (602) is arranged on the material dividing pipe, one end of the material dividing pipe (601) is connected with a material discharging pipe of a cyclone (102) of a last-stage kiln tail preheater, and the other end of the material dividing pipe is connected with an outlet air pipe of a first-stage cyclone (201); the feeding pipe of the second-stage cyclone cylinder (202) is also connected with a material distribution pipe positioned at the upper part of the high-temperature gate valve I (602), and the material distribution valve (205) is arranged at the branch position of the feeding pipe of the second-stage cyclone cylinder (202).
4. The calcium circulation semi-dry desulphurization system of the cement clinker production line according to claim 2, wherein the cooling unit (20) is connected with the outlet air pipe of the decomposing furnace (101) through a material taking unit; the material taking unit comprises a material taking cyclone (604), a high-temperature gate valve II (605) is arranged on an inlet pipeline of the material taking cyclone (604), and a high-temperature gate valve III (606) is arranged on an outlet air pipe of the material taking cyclone (604); an inlet pipeline of the material taking cyclone (604) is connected with an outlet air pipe of the decomposing furnace (101), an outlet air pipe of the material taking cyclone (604) is connected with an outlet air pipe of a last-stage or penultimate kiln tail preheater, and a discharging pipe of the material taking cyclone (604) is connected with an outlet air pipe of the first-stage cyclone (201).
5. The cement clinker production line calcium circulation semi-dry desulfurization system as recited in claim 2, characterized in that the discharge opening of the first stage cyclone (201) is connected with a collection bin (206), the discharge opening of the collection bin (206) is provided with a gate valve I (207) and a screw feeder (208) with a meter, and the outlet of the screw feeder (208) with the meter is connected with the digestion unit (30).
6. The calcium circulation semi-dry desulfurization system for cement clinker production line as claimed in claim 2, wherein the digestion mode of the digestion unit (30) is dry digestion, and the exhaust port of the digestion unit (30) is connected with the exhaust gas treatment system (204) through the air pipe of the cooling unit (20); the digestion unit (30) is also provided with a quicklime feed inlet (301).
7. The calcium circulation semi-dry desulfurization system for cement clinker production line as claimed in claim 1, wherein the desulfurization unit (40) comprises an inlet duct (401) provided at a lower portion of the desulfurization unit, an absorption tower (402) provided at an upper portion of the desulfurization unit, and a venturi tube (403) provided between and connected to the inlet duct and the absorption tower; a water spraying device (404) is arranged in the absorption tower (402); the discharge hole of the digestion unit (30) is connected with an air inlet pipeline (401) or an absorption tower (402) of a desulfurization unit; the desulfurization unit (40) is also provided with a hydrated lime charging port (405).
8. The cement clinker production line calcium circulation semi-dry desulfurization system as recited in claim 1, wherein the desulfurization slag conveying unit (80) comprises a roots blower (801), a heater (802) and a storage bin (803) which are connected in sequence through a conveying pipeline, a discharge port of the storage bin (803) is provided with a second gate valve (804) and an air locking member, the desulfurization slag discharged by the air locking member is fed into a column section part above a tertiary air pipe (1011) of a decomposing furnace (101), and a dust collector (806) is arranged above the storage bin (803);
a desulfurized slag bin (810) is arranged between the dust collection unit (50) and the desulfurized slag conveying unit (80), a gate valve III (811) and a rotary feeder (812) are arranged at a discharge hole of the desulfurized slag bin (810), and an outlet of the rotary feeder (812) is connected with a conveying pipeline between the heater (802) and the storage bin (803).
9. The calcium circulation semi-dry desulphurization system of the cement clinker production line according to claim 8, wherein the conveying pipeline of the desulphurization slag conveying unit (80) and the storage bin (803) are provided with external heat-insulating layers.
10. The cement clinker production line calcium circulation semi-dry desulfurization system as recited in claim 7, wherein the discharge port of the dust collection unit (50) is connected with the air inlet pipeline (401) of the desulfurization unit; and a discharge hole of the dust collection unit (50) is also provided with an external discharge disposal pipeline, and the external discharge disposal pipeline is connected with a raw material warehouse or a kiln tail preheater.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110052151A (en) * | 2019-06-06 | 2019-07-26 | 天津水泥工业设计研究院有限公司 | One kind being based on cement clinker production line calcium circulation half dry desulphurization system system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110052151A (en) * | 2019-06-06 | 2019-07-26 | 天津水泥工业设计研究院有限公司 | One kind being based on cement clinker production line calcium circulation half dry desulphurization system system |
| CN110052151B (en) * | 2019-06-06 | 2023-12-26 | 天津水泥工业设计研究院有限公司 | Calcium-cycle semi-dry desulfurization system based on cement clinker production line |
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