CN214039600U - Kiln tail flue gas waste heat utilization system of cement rotary kiln - Google Patents

Abstract

The utility model provides a kiln tail flue gas waste heat utilization system of cement rotary kiln, including kiln tail preheater, the kiln tail waste heat boiler who installs the economizer and connect in the decomposing furnace of kiln tail smoke chamber, the delivery port of economizer passes through the steam pocket and communicates with steam turbine steam inlet chamber, kiln tail preheater includes the one-level whirlwind section of thick bamboo, second grade whirlwind section of thick bamboo, tertiary whirlwind section of thick bamboo, level four whirlwind section of thick bamboo and the five-level whirlwind section of thick bamboo that sets gradually from top to bottom; the top of the primary cyclone cylinder is provided with a flue gas discharge pipe communicated with the kiln tail waste heat boiler; the upper part of the secondary cyclone cylinder is provided with a heat exchange inner cylinder which is communicated with the steam pocket. When the rotary kiln stops operating, the heat source of the secondary cyclone cylinder and the heat source at the tail of the kiln can continuously enable the coal economizer to generate steam, and the waste heat generating capacity and the operation rate of waste heat power generation can be improved.

Description

Kiln tail flue gas waste heat utilization system of cement rotary kiln

Technical Field

The utility model relates to a cement kiln waste heat utilization system especially relates to a rotary cement kiln's kiln tail flue gas waste heat utilization system.

Background

The predecomposition kiln technology of the new dry method cement is widely applied in the cement production industry of China, and is characterized in that a decomposing furnace is additionally arranged between a preheater and the tail end of a rotary kiln, fuel is sprayed into the decomposing furnace for combustion, and raw materials preheated to about 750 ℃ by the preheater are fed into the decomposing furnace and mixed with the fuel sprayed into the decomposing furnace, so that the heat release process of the fuel combustion and the heat absorption process of decomposing carbonate in the raw materials are rapidly carried out in the decomposing furnace in a suspended state, and the decomposition rate of the raw materials before entering the kiln reaches more than 90 percent.

The general novel dry-method cement predecomposition kiln technology is usually provided with a kiln tail waste heat boiler to form a low-temperature waste heat utilization system. The common utilization mode of the existing cement rotary kiln pure low-temperature waste heat power generation system is as follows: the flue gas of 300 ~ 350 ℃ of C1 preheater (being one-level preheater) export gets into a kiln tail exhaust-heat boiler and produces low pressure steam, and steam gets into steam turbine drive generator electricity generation, and this low temperature waste heat utilization system has effectively reduced the energy consumption of cement production, has improved the utilization ratio of the energy. However, in practical use, when the rotary kiln stops operating, the low-temperature waste heat utilization system cannot continue to operate and generate electricity, so that the power generation efficiency is not high.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a rotary cement kiln's kiln tail flue gas waste heat utilization system to solve the lower problem of generating efficiency that current rotary kiln's waste heat utilization system exists.

The utility model discloses a realize like this:

a kiln tail flue gas waste heat utilization system of a cement rotary kiln comprises a kiln tail preheater, a kiln tail waste heat boiler provided with an economizer and a decomposing furnace connected to a kiln tail smoke chamber, wherein a water outlet of the economizer is communicated with a steam inlet chamber of a steam turbine through a steam pocket;

connecting pipelines are respectively communicated between the upper part of the first-stage cyclone and the top of the second-stage cyclone, between the upper part of the second-stage cyclone and the top of the third-stage cyclone, between the upper part of the third-stage cyclone and the top of the fourth-stage cyclone, between the upper part of the fourth-stage cyclone and the top of the fifth-stage cyclone, and between the upper part of the fifth-stage cyclone and the top of the decomposing furnace; the bottom of the decomposing furnace is provided with a flue gas input pipe which is used for connecting a kiln tail smoke chamber;

the bottom parts of the primary cyclone cylinder, the secondary cyclone cylinder, the tertiary cyclone cylinder, the fourth-stage cyclone cylinder and the fifth-stage cyclone cylinder are all provided with blanking pipes;

the top of the primary cyclone cylinder is provided with a flue gas discharge pipe communicated with the kiln tail waste heat boiler;

and the upper part of the secondary cyclone cylinder is provided with a heat exchange inner cylinder communicated with the steam drum.

The first-stage cyclone cylinder, the second-stage cyclone cylinder and the blanking pipe at the bottom of the third-stage cyclone cylinder are communicated with the cyclone cylinder at the next stage, and the fourth-stage cyclone cylinder and the blanking pipe at the bottom of the fifth-stage cyclone cylinder are communicated with the flue gas input pipe.

The heat exchange inner barrel comprises a plurality of first heat exchange tubes and a plurality of second heat exchange tubes, the first heat exchange tubes and the second heat exchange tubes are arranged in a staggered mode, the first heat exchange tubes and the second heat exchange tubes are of U-shaped tube structures, each first heat exchange tube and each second heat exchange tube comprise inner side straight tubes, outer side straight tubes and connecting bent tubes connected between the inner side straight tubes and the outer side straight tubes, the inner side straight tubes are arranged into a first cylindrical structure, the outer side straight tubes are arranged into a second cylindrical structure, the first cylindrical structure is coaxially arranged on the inner side of the second cylindrical structure, and connecting flat steel is arranged between every two adjacent inner side straight tubes;

a first annular pipeline communicated with the end part of the inner side straight pipe is fixedly arranged at one axial end of the first cylinder structure, and a first pipe orifice is communicated with the first annular pipeline;

and one axial end of the second cylinder structure is fixedly provided with a second annular pipeline communicated with the end part of the outer side straight pipe, and a second pipe orifice is communicated with the second annular pipeline.

The length of the inner side straight pipe of the second heat exchange pipe is greater than that of the inner side straight pipe of the first heat exchange pipe.

The heat exchange inner cylinder comprises a cylinder body and spiral heat exchange tubes wound on the outer circumferential surface of the cylinder body.

The utility model has the advantages that:

the utility model discloses the upper portion of second grade whirlwind section of thick bamboo sets up the heat transfer inner tube with the steam pocket intercommunication, makes the steam that the economizer separates through the reheating of the heat transfer inner tube of second grade whirlwind section of thick bamboo, can improve the superheated steam volume that gets into the steam turbine, and then improves the total enthalpy drop in the steam turbine, the interior efficiency that the steam turbine is relative and thermodynamic system's cyclic thermal efficiency, reduces the heat consumption to improve waste heat utilization system operation economic benefits. More importantly, when the rotary kiln stops running, the heat source of the secondary cyclone cylinder and the heat source at the tail of the kiln can continuously enable the coal economizer to generate steam, and the waste heat generating capacity and the operation rate of waste heat power generation can be improved.

Drawings

Fig. 1 is a schematic structural diagram of the present invention;

fig. 2 is a schematic structural diagram of the heat exchange inner cylinder of the present invention.

In the figure: 1. a kiln tail preheater; 2. a kiln tail waste heat boiler; 3. a decomposing furnace; 4. a steam drum; 5. a flue gas input pipe; 6. a flue gas discharge pipe; 7. an inner heat exchange cylinder; 8. a raw material input pipe; 11. a primary cyclone; 12. a secondary cyclone; 13. a tertiary cyclone; 14. a four-stage cyclone; 15. a fifth stage cyclone; 16. a discharging pipe; 17. connecting a pipeline; 21. a coal economizer; 22. an exhaust gas discharge pipe; 61. a bypass exhaust gas discharge pipe; 62. an electric butterfly valve; 71. a first heat exchange tube; 72. a second heat exchange tube; 73. an inner straight tube; 74. an outer straight tube; 75. connecting a bent pipe; 76. connecting flat steel; 751. a first annular duct; 752. A first nozzle; 753. installing a flange; 754. a first externally expanded pipe; 761. a second toroidal tube; 762. A second orifice; 763. a second outer expanding tube; 764. supporting the flange plate.

Detailed Description

The present invention is further illustrated by the following examples, which are given by way of illustration only and are not intended to limit the scope of the present invention in any way.

As shown in fig. 1, a kiln tail flue gas waste heat utilization system of a cement rotary kiln comprises a kiln tail preheater 1, a kiln tail waste heat boiler 2 provided with an economizer 21 and a decomposing furnace 3 connected to a kiln tail smoke chamber. The water outlet of the economizer 21 is communicated with a steam inlet chamber of a steam turbine through a steam pocket 4, and the kiln tail preheater 1 comprises a first-stage cyclone 11, a second-stage cyclone 12, a third-stage cyclone 13, a fourth-stage cyclone 14 and a fifth-stage cyclone 15 which are sequentially arranged from top to bottom. Connecting pipelines 17 are respectively communicated between the upper part of the first-stage cyclone 11 and the top of the second-stage cyclone 12, between the upper part of the second-stage cyclone 12 and the top of the third-stage cyclone 13, between the upper part of the third-stage cyclone 13 and the top of the fourth-stage cyclone 14, between the upper part of the fourth-stage cyclone 14 and the top of the fifth-stage cyclone 15, and between the upper part of the fifth-stage cyclone 15 and the top of the decomposing furnace 3. The bottom of the decomposing furnace 3 is provided with a flue gas input pipe 5 which is used for connecting a kiln tail smoke chamber.

The bottom of the first-stage cyclone 11, the bottom of the second-stage cyclone 12, the bottom of the third-stage cyclone 13, the bottom of the fourth-stage cyclone 14 and the bottom of the fifth-stage cyclone 15 are all provided with a feeding pipe 16. The top of the primary cyclone 11 is provided with a flue gas discharge pipe 6 communicated with the kiln tail waste heat boiler 2, the flue gas discharge pipe 6 is also communicated with a bypass waste gas discharge pipe 61, and the bypass waste gas discharge pipe 61 and the pipe section of the flue gas discharge pipe 6 communicated between the bypass waste gas discharge pipe 61 and the kiln tail waste heat boiler 2 are both provided with an electric butterfly valve 62. And the bottom of the kiln tail waste heat boiler 2 is provided with an exhaust gas discharge pipe 22. The raw material input pipe 8 is arranged on the connecting pipeline 17 between the first-stage cyclone 11 and the second-stage cyclone 12, and the discharging pipes 16 at the bottoms of the first-stage cyclone 11, the second-stage cyclone 12 and the third-stage cyclone 13 are communicated with the next-stage cyclone, namely: the bottom end of a feeding pipe 16 of the primary cyclone 11 is communicated with a connecting pipeline 17 arranged between the secondary cyclone 12 and the tertiary cyclone 13, and the joint of the feeding pipe 16 and the connecting pipeline 17 is close to the secondary cyclone 12; the bottom end of a feeding pipe 16 of the secondary cyclone 12 is communicated with a connecting pipeline 17 arranged between the tertiary cyclone 13 and the quaternary cyclone 14, and the joint of the feeding pipe 16 and the connecting pipeline 17 is close to the tertiary cyclone 13; the bottom end of a feeding pipe 16 of the third-stage cyclone 13 is communicated with a connecting pipeline 17 arranged between the fourth-stage cyclone 14 and the fifth-stage cyclone 15, and the joint of the feeding pipe 16 and the connecting pipeline 17 is close to the fourth-stage cyclone 14. The discharge pipes 16 at the bottoms of the four-stage cyclone cylinder 14 and the five-stage cyclone cylinder 15 are communicated with the flue gas input pipe 5. As shown in FIG. 1 and FIG. 2, the upper part of the secondary cyclone 12 is provided with a heat exchange inner cylinder 7 for communicating with the steam drum 4. Also set up the inner tube in one-level cyclone 11, tertiary cyclone 13, level four cyclone 14 and the five-stage cyclone 15, this inner tube set up to prior art, do not conduct the utility model discloses an innovation point, the utility model discloses an innovation point is the setting of heat transfer inner tube 7.

The utility model discloses in, 7 structures of heat transfer inner tube do: the heat exchange inner cylinder 7 comprises a cylinder body and a spiral heat exchange tube wound on the outer circumferential surface of the cylinder body, the spiral inner diameter of the spiral heat exchange tube is equal to the outer diameter of the cylinder body, the spiral heat exchange tube can be fixedly connected with the outer circumferential surface of the cylinder body in a welding mode, and one section of the spiral heat exchange tube is communicated with a steam pocket (the heat exchange inner cylinder shown in figure 1).

The structure of the heat exchange inner barrel 7 can also be as shown in the utility model figure 2: the heat exchange inner cylinder 7 comprises a plurality of first heat exchange tubes 71 and a plurality of second heat exchange tubes 72, the first heat exchange tubes 71 and the second heat exchange tubes 72 are arranged in a staggered manner, the first heat exchange tubes 71 and the second heat exchange tubes 72 are of U-shaped tube structures, each first heat exchange tube 71 and each second heat exchange tube 72 comprises an inner straight tube 73, an outer straight tube 74 and a connecting bent tube 75 connected between the inner straight tube 73 and the outer straight tube 74, the inner straight tubes 73 are arranged into a first cylindrical structure, the outer straight tubes 74 are arranged into a second cylindrical structure, the first cylindrical structure is coaxially arranged on the inner side of the second cylindrical structure, the connecting bent tube 75 is positioned at the same axial end of the first cylindrical structure or the second cylindrical structure, a connecting flat steel 76 is arranged between every two adjacent inner straight tubes 73, the top end of the connecting flat steel 76 is flush with the top end of the inner straight tube 73, and the bottom end of the connecting flat steel 76 is flush with the bottom end of the inner straight tube 73, the connecting flat steel 76 is hermetically connected with the inner straight pipe 73 on the corresponding side in a welding mode. The axial end of the first cylindrical structure is fixedly provided with a first annular pipeline 751 communicated with the end of the inner straight pipe 73, the first annular pipeline 751 is positioned at the end of the first cylindrical structure opposite to the connecting elbow 75, the first annular pipeline 751 is communicated with a first pipe opening 752, a mounting flange 753 fixedly connected with the upper part in the secondary cyclone cylinder 12 is arranged between the first annular pipeline 751 and the axial corresponding end of the inner straight pipe of the first cylindrical structure, the corresponding end of the inner straight pipe of the first cylindrical structure is provided with a first outward-extending pipe 754 communicated with the first annular pipeline 751, and the first outward-extending pipe 754 penetrates through the mounting flange 753. A second annular pipeline 761 communicated with the end part of the outer straight pipe 74 is fixedly arranged at one axial end of the second cylinder structure, the second annular pipeline 761 is positioned at one end of the second cylinder structure opposite to the connecting bent pipe 75, a second pipe orifice 762 is communicated and arranged on the second annular pipeline 761, and a second outer expanding pipe 763 communicated with the second annular pipeline 761 is arranged at the corresponding end of the outer straight pipe of the second cylinder structure. The axial middle part of the outer circumference of the first cylinder structure is coaxial and fixedly provided with a supporting flange plate 764 used for supporting the outer straight pipe, and the outer straight pipe penetrates through the supporting flange plate 764. The length of the inner straight pipe 73 of the second heat exchange pipe 72 is greater than that of the inner straight pipe 73 of the first heat exchange pipe 71, so that the kiln tail waste heat boiler 2 can continuously generate superheated steam.

As shown in fig. 1 and fig. 2, the working process of the present invention is: the kiln tail flue gas is divided into two paths after passing through a kiln tail preheater 1 from bottom to top, one part of the flue gas is conveyed to a kiln tail waste heat boiler 2 to heat water supplied by a coal economizer so as to generate steam, and the other part of the flue gas is used as a standby heat source of the kiln tail waste heat boiler 2 through a bypass waste gas discharge pipe. Raw material enters a connecting pipeline 17 between the primary cyclone 11 and the secondary cyclone 12 through a raw material input pipe 8 and is heated by rising flue gas in the connecting pipeline, and the heated raw material enters the primary cyclone 11 for gas-solid separation. The separated raw material enters a connecting pipeline 17 of the secondary cyclone 12 through a feeding pipe 16 of the primary cyclone 11 and is heated by the rising flue gas in the secondary cyclone 12, and the heated raw material enters the secondary cyclone 12 for gas-solid separation. The separated raw material enters a connecting pipeline 17 of the third-stage cyclone 13 through a feeding pipe 16 of the second-stage cyclone 12 and is heated by rising flue gas in the third-stage cyclone 13, and the heated raw material enters the third-stage cyclone 13 for gas-solid separation. The separated raw material enters a connecting pipeline 17 of the four-stage cyclone 14 through a discharging pipe 16 of the three-stage cyclone 13 and is heated by rising flue gas in the four-stage cyclone 14, and the heated raw material respectively enters the four-stage cyclone 14 and the five-stage cyclone 15 for gas-solid separation. The separated raw materials enter the decomposing furnace 3 through the feeding pipes 16 of the four-stage cyclone 14 and the five-stage cyclone 15 respectively. The utility model discloses when carrying out the predecomposition to the raw material, the first mouth of pipe 752 and the steam pocket 4 intercommunication of the heat transfer inner tube 7 of second grade whirlwind section of thick bamboo, the second mouth of pipe of heat transfer inner tube 7 and the inlet chamber intercommunication of steam turbine. The high-temperature flue gas in the secondary cyclone cylinder can heat the steam-water mixture flowing through the heat exchange inner cylinder 7, so that steam can be continuously generated in the economizer, and the waste heat generating capacity and the operation rate of waste heat power generation are improved.

The utility model discloses in, the 450-600 ℃ waste gas of the entry of second grade whirlwind section of thick bamboo sets up heat transfer inner tube 7, can make kiln tail exhaust-heat boiler independently produce steam, firstly can improve the waste heat generated energy, secondly can improve the operating rate of cogeneration. In actual operation: taking a rotary kiln of 5000t/d as an example, the system has about 35 ten thousand of investment cost, can generate about 2 tons of steam in operation, increases the generated energy by 300 KW.h per hour, and has 100 ten thousand of annual income.

The above description in this specification is merely illustrative of the present invention. Various modifications, additions and substitutions may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims (5)

1. A kiln tail flue gas waste heat utilization system of a cement rotary kiln comprises a kiln tail preheater, a kiln tail waste heat boiler provided with an economizer and a decomposing furnace connected to a kiln tail smoke chamber, wherein a water outlet of the economizer is communicated with a steam inlet chamber of a steam turbine through a steam pocket;

connecting pipelines are respectively communicated between the upper part of the first-stage cyclone and the top of the second-stage cyclone, between the upper part of the second-stage cyclone and the top of the third-stage cyclone, between the upper part of the third-stage cyclone and the top of the fourth-stage cyclone, between the upper part of the fourth-stage cyclone and the top of the fifth-stage cyclone, and between the upper part of the fifth-stage cyclone and the top of the decomposing furnace; the bottom of the decomposing furnace is provided with a flue gas input pipe which is used for connecting a kiln tail smoke chamber;

the bottom parts of the primary cyclone cylinder, the secondary cyclone cylinder, the tertiary cyclone cylinder, the fourth-stage cyclone cylinder and the fifth-stage cyclone cylinder are all provided with blanking pipes;

the top of the primary cyclone cylinder is provided with a flue gas discharge pipe communicated with the kiln tail waste heat boiler;

and the upper part of the secondary cyclone cylinder is provided with a heat exchange inner cylinder communicated with the steam drum.

2. The kiln tail flue gas waste heat utilization system of the rotary cement kiln as claimed in claim 1, wherein the primary cyclone, the secondary cyclone and the blanking pipe at the bottom of the tertiary cyclone are all communicated with the next-stage cyclone, and the four-stage cyclone and the blanking pipe at the bottom of the five-stage cyclone are communicated with the flue gas input pipe.

3. The kiln tail flue gas waste heat utilization system of the rotary cement kiln as recited in claim 1, wherein the heat exchange inner cylinder comprises a plurality of first heat exchange tubes and a plurality of second heat exchange tubes, the first heat exchange tubes and the second heat exchange tubes are arranged in a staggered manner, the first heat exchange tubes and the second heat exchange tubes are of a U-shaped tube structure, each of the first heat exchange tubes and the second heat exchange tubes comprises an inner straight tube, an outer straight tube and a connecting bent tube connected between the inner straight tube and the outer straight tube, the plurality of inner straight tubes are arranged in a first cylindrical structure, the plurality of outer straight tubes are arranged in a second cylindrical structure, the first cylindrical structure is coaxially arranged at the inner side of the second cylindrical structure, and a connecting flat steel is arranged between two adjacent inner straight tubes;

a first annular pipeline communicated with the end part of the inner side straight pipe is fixedly arranged at one axial end of the first cylinder structure, and a first pipe orifice is communicated with the first annular pipeline;

and one axial end of the second cylinder structure is fixedly provided with a second annular pipeline communicated with the end part of the outer side straight pipe, and a second pipe orifice is communicated with the second annular pipeline.

4. The kiln tail flue gas waste heat utilization system of the rotary cement kiln as recited in claim 3, wherein the length of the inner side straight tube of the second heat exchange tube is greater than the length of the inner side straight tube of the first heat exchange tube.

5. The kiln tail flue gas waste heat utilization system of the rotary cement kiln as recited in claim 1, wherein the heat exchange inner cylinder comprises a cylinder body and spiral heat exchange tubes wound around the outer circumferential surface of the cylinder body.

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