WO2011032354A1

WO2011032354A1 - External combustion and internal heating type coal retort furnace

Info

Publication number: WO2011032354A1
Application number: PCT/CN2010/001393
Authority: WO
Inventors: 刘振强; 张毅; 苗文华; 张旭辉; 石长江; 白中华
Original assignee: 北京国电富通科技发展有限责任公司
Priority date: 2009-09-15
Filing date: 2010-09-10
Publication date: 2011-03-24
Also published as: AU2010295138A1; CN101691493B; CN101691493A; AU2010295138B2; IN2012DN02436A

Abstract

An external combustion and internal heating type coal retort furnace comprises a drying section used for drying raw coal material, a retort section used for retorting the dried raw coal material, a cooling section used for cooling the retorted products from the retort section, and a cold flue gas pipeline used for ducting the cold flue gas produced in the drying section into the cooling section. The said coal retort furnace is energy saving and environmental friendly, and ensures improved retorting efficiency on the whole.

Description

External combustion internal heat type coal dry distillation furnace

The invention relates to a coal dry distillation furnace, in particular to an external combustion internal heat type coal dry distillation furnace. Background technique

Dry distillation is the reaction process in which solid or organic matter is decomposed by heating under air conditions. The result of the dry distillation is the formation of various gases, vapors, and solid residues. The mixture of gas and vapor is cooled and separated into a gas and a liquid. Dry distillation is a production process that has long been familiar and adopted by humans, such as charcoal for wood distillation, and wood (methanol), wood acetic acid, and the like. Dry distillation has always been an important method in the chemical processing of coal. After the coal is retorted, the composition and aggregation state of the raw materials will change. The solid, gaseous and liquid substances in the product are available, and semi-coke, coal tar, crude ammonia water and coke oven gas can be obtained. Most of the cognac production uses intermittent operation, but the retorting device may vary depending on the type and purpose of the raw materials, and generally can be classified into two types: external combustion type and self-ignition type. The external combustion type is that the raw material is placed in a closed carbonization furnace (kiln) made of metal or refractory material, and the external fuel is used to burn and supply heat. Modern cognac devices use this type. The self-ignition type is to dry a certain amount of air into the dry distillation furnace to make some of the dry distillation raw materials burn and release heat, so the utilization rate of raw materials is low, and it is only used in small-scale production. The external combustion type coal retort in the prior art mostly adopts the Lurgi furnace of the 1930s and its improved furnace type. The Lurgi furnace is also called the three-stage furnace. As shown in Figure 1, it is divided into three sections: drying, dry distillation and cooling. The solid raw material is sent to the coal hopper by the top belt, and is evenly distributed in the drying section 100. The combustible gas is mixed and burned in the drying section combustion chamber 500 and air, and is mixed with the circulating drying gas extracted from the intermediate archway to become a heat carrier. The raw material coal is dried by a dry circulation blower through the lower arch of the drying section 200 to the drying section 200. The exhaust gas is evacuated by the chimney after passing through the archway on the drying section 200. The dried coal enters the cognac section 300. The hot gas after combustion of the combustible gas and the air in the dry distillation section combustion chamber 600 is about ll OO'C, and the hot gas is mixed with the secondary gas to become a heat carrier of 700-800 ° C, and the coal is contacted with the coal to make the coal at 450-500 ' C dry Distillation, steaming out oil and gas. The waste gas generated in the dry section 300 is subjected to coal tar removal treatment by the aftertreatment system 700. After the coal briquettes are burnt into semi-coke, it enters the cooling section 400. After three times of gas cooling, it falls into the coke hopper and then falls into the coke zone to send out the coke field.

The improvement of the Lurgi furnace is mainly focused on uniform fabric, reduced circulation gas resistance, improved heating conditions, improved ash removal equipment, and simplified equipment. However, the existing various modified Lurgi furnaces have the following disadvantages: Most of the cold flue gas is directly emptied and is not well utilized, resulting in low dry distillation efficiency; further, the coal in the drying section The water content is large, causing the coal to enter the dry distillation section when the water content is too large (lwt% (% by weight or more)), which will greatly affect the dry distillation efficiency; in addition, the waste gas produced by the dry distillation section is first treated, and then The quenching is carried out by passing through the cooling section, and then evacuated through the chimney of the furnace body through the chimney, and no waste heat is utilized for the gas heated in the cooling section, resulting in a large waste of thermal energy. Summary of the invention

Therefore, the technical problem to be solved by the present invention is that the efficiency of the existing coal dry quenching furnace is low and the thermal energy utilization of the flue gas after the cooling section is not good, and a waste heat of the flue gas passing through the cooling layer is proposed. An external combustion internal thermal coal dry quenching furnace that preheats the untreated coal seam to improve the coal dry distillation efficiency. In order to solve the above technical problems, an external combustion internal heat type coal retort furnace of the present invention is from top to bottom:

a drying section for drying the raw coal, and obtaining a cold flue gas at the same time as the drying treatment; a dry kneading section for dry-treating the dried raw coal, the raw coal is subjected to dry distillation to form a dry distillation product;

a cooling section for cooling the dry distillation product produced in the dry distillation section by introducing the cold flue gas;

The cold flue gas generated by the drying section is conducted to a cold flue gas duct of the cooling section.

a preheating section for preheating the raw coal is further disposed above the drying section; the cold flue gas is heated to generate hot flue gas after the cooling section, and the coal coke oven is further provided with The hot flue gas is conducted to the exhaust gas conduit of the preheating section. Connected to the cold flue gas duct with a circulating power device, which can cause the cold flue gas generated in the drying section to be conducted to the cooling section via the cold flue gas duct, and then through the exhaust gas The conduit is electrically connected to the preheating section. The circulating power unit is a circulating fan. The cold flue gas duct is connected with an emptying passage for emptying the excess cold flue gas which is unnecessary for the cooling section.

At the waste gas outlet of the dry distillation section, an aftertreatment system for generating waste gas to perform coal removal tar when the raw coal is subjected to dry distillation treatment in the dry distillation section is also connected. Also connected between the flue gas outlet of the aftertreatment system and the drying section is a dry burner that combusts a portion of the gas produced in the aftertreatment system to produce a drying for use in the drying section Treated dry fumes. A drying duct is further connected between the cold flue gas duct and the flue gas outlet of the dry burner, which can mix a part of the cold flue gas generated in the drying section with the dry flue gas to adjust the The temperature of the drying process in the drying section. Also connected between the flue gas outlet of the aftertreatment system and the dry distillation section is a dry distillation burner that combusts a portion of the gas produced in the aftertreatment system to produce for use in the dry distillation section Cognac treated dry cognac. A dry distillation line is further connected between the flue gas outlet of the aftertreatment system and the flue gas outlet of the dry distillation burner, which can mix a part of the gas generated in the aftertreatment system with the dry distillation smoke The temperature of the retorting treatment in the dry distillation section is adjusted. A combustion air blower is provided at the flue gas inlet of the dry combustor and/or the dry distillation burner, respectively, to provide combustion air to the dry combustor and/or the dry distillation combustor. The above technical solution of the present invention has the following advantages compared with the prior art: First, the external combustion internal heat type coal dry distillation furnace of the present invention fully utilizes the cold flue gas generated in the process to cool the dry distillation product, thereby improving the overall The dry distillation efficiency; while cooling the dry distillation product, the large amount of sulfur in the flue gas is removed, thereby achieving energy saving and environmental protection. Further, the external combustion internal heat type coal retort furnace of the present invention is provided with preheating, drying, drying and cooling, fully utilizing the waste heat in the flue gas, and removing a large amount of strontium in the flue gas while cooling the semi-coke. Realize energy saving and environmental protection. Further, in the external combustion internal heat type dry distillation furnace of the present invention, since the raw coal is preheated, the water content in the raw coal after the drying treatment is less than 1% by weight, and the drying efficiency is high. Moreover, the prior art directly uses quenching gas treated by de-coal tar to perform quenching and cooling, and the main component of quenching flue gas is carbon monoxide. At this time, if air is mixed in the cooling section chamber, explosion is likely to occur; The external combustion internal heat type coal dry quenching furnace generates waste gas during dry distillation and is not used for quenching and cooling treatment, but uses quenching and cooling with cold flue gas whose main components are water vapor, carbon dioxide and nitrogen, and the chemical property of the flue gas is stable. Minimize the occurrence of danger. BRIEF DESCRIPTION OF THE DRAWINGS In order to make the content of the present invention easier to understand, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

1 is a schematic view showing the structure of a Lurgi furnace in the prior art;

Figure 2 is a schematic structural view of a specific embodiment of an external combustion internal heat type coal-drying furnace of the present invention;

Reference numerals are denoted by: 1 - preheating section; 2-drying section; 3-dry distillation section; 4-cooling section; 5-dry burner; 6-dry distillation burner; 7-aftertreatment system; 9-circulating fan; 10 - cold flue gas pipeline; 11 - drying pipeline; 12 - exhaust gas pipeline; 13 - emptying pipeline; 14 - dry distillation pipeline; 100 - coal hopper; 200 - drying section; 300 - dry distillation section; - cooling section; 500-dry section combustion chamber; 600- dry distillation section combustion chamber; 700-aftertreatment system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Figure 2 shows a specific embodiment of an external combustion internal heat type coal dry distillation furnace of the present invention, an external combustion internal heat type coal dry distillation furnace, which is from top to bottom: preheating section 1, drying section 2 , dry distillation section 3 and cooling section 4. The preheating section is disposed above the drying section and communicates with the drying section for preheating the raw coal; the drying section is used for drying the raw coal, and simultaneously To the cold flue gas; the dry distillation section 3 is used for the distillation treatment of the dried raw coal, the raw coal is subjected to dry distillation to form a semi-coke; the cooling section 4 is obtained by introducing the cold flue gas The semi-coke produced therein is cooled, and at the same time, hot flue gas is obtained. The coal retort furnace is further provided with a cold flue gas duct 10 that conducts the cold flue gas generated by the drying section 2 to the cooling section 4, and the hot flue gas generated by the cooling section An exhaust gas conduit 12 is connected to the preheating section. The cold flue gas duct 10 is connected with a circulation fan 9 which can cause the cold flue gas generated in the drying section 2 to be conducted to the cooling section via the cold flue gas duct 10, and then Conducted to the preheating section 1 via the exhaust gas conduit 12. The cold flue gas duct 10 is connected to an evacuation passage 13 for venting excess cold flue gas which is unnecessary for the cooling section 4. The external combustion internal heat type coal-drying furnace of the present invention is further connected at the waste gas outlet of the dry distillation section 3 with a post-treatment for generating waste gas by performing dry distillation treatment on the raw coal in the dry commission section 3 System 7. A drying burner 5 is further connected between the flue gas outlet of the aftertreatment system 7 and the drying section 2, and is also connected between the cold flue gas duct 10 and the flue gas outlet of the drying burner 5. Dry the pipe 11. The drying burner 5 combusts a portion of the gas produced in the aftertreatment system 7 to produce dry flue gas for the drying process in the drying section 2, and the drying duct 11 may dry the drying section A portion of the cold flue gas produced in 2 is mixed with the dry flue gas to adjust the temperature of the drying process in the drying section 2. In addition, a dry distillation burner 6 is connected between the flue gas outlet of the aftertreatment system 7 and the dry section 3, and the flue gas outlet of the aftertreatment system 7 and the smoke of the dry distillation burner 6 A dry distillation conduit 14 is also connected between the gas outlets. The dry distillation burner 6 may combust a portion of the gas produced in the aftertreatment system 7 to produce dry distillation flue gas for the dry distillation treatment in the dry distillation section 3, and the dry distillation conduit 14 may Post-treatment is the temperature of the treatment. The combustion burner 5 and the flue gas inlet of the dry distillation burner 6 are also connected to a combustion air blower 8 that supplies combustion air to the dry burner 5 and the dry burner 6, respectively. The external combustion internal heat type coal dry quenching furnace of the present invention has the following steps: the preheating step, that is, preheating the raw coal; a, drying the preheated raw coal, And at the same time produce cold flue gas; b, dry treatment of the dried coal to form a half C. The cold flue gas generated in the step a is introduced into the semi-coke produced by the distillation process, and the quenching and cooling process is performed on the semi-coke, and hot flue gas is generated at the same time. The new raw coal to be treated is placed in a preheat treatment in the preheating step for the new raw coal. The main component of the cold flue gas produced in the step a is (volume percentage content): water vapor 48-50%, nitrogen 20-22%, carbon dioxide 28-30%. In the step b, the waste gas generated during the dry distillation is not used for the quenching and cooling treatment. The waste gas generated in the step b in the dry distillation is used only for the dry treatment in the step a and/or the dry distillation treatment in the step b. Wherein: part of the waste gas is mixed with air to form a dry flue gas for use in the drying process in the step a. A portion of the cold flue gas produced in the step a is mixed with the dry flue gas to adjust the temperature of the drying process in the step a. Part of the waste gas is mixed with air to form a dry distillation flue gas for use in the dry distillation treatment in the step b. The temperature of the step. The temperature of the preheated coal block in the preheating step is 75 ° (the temperature of the coal block subjected to the drying process in step a is 180 ° C; the temperature of the cognac treatment in the step b is 530 ° C. The temperature of the coal block subjected to quenching and cooling treatment in step c is 130. The waste gas has a post-treatment step for removing coal tar before combustion. The external combustion internal heat type coal dry distillation furnace of the present invention is normal. During the working process, the preheating section, the drying section, the dry distillation section and the cooling section are filled with coal or semi-coke, and the coal block moves downward as a whole and produces finished semi-coke. The preheating section is raw coal. In the drying section and the dry section, the coal block is processed, and the cooling section is the semi-coke to be cooled. The waste gas generated in the dry distillation section is subjected to post-treatment system to remove coal tar to obtain gas. Part of the gas obtained by the system is burned by the dry burner to generate a relatively high temperature dry flue gas, and the dry flue gas is mixed with a part of the cold flue gas passing through the drying pipe to obtain a flue gas having a suitable temperature. Drying treatment in the drying section; combustion of another portion of the gas obtained by the aftertreatment system through the dry distillation burner produces a higher temperature dry flue gas, which is passed through the dry conduit A portion of the post-treatment results in gas mixing for a suitable temperature flue gas for dry distillation in the dry distillation section. The combustion air in the dry combustor and the dry distillation burner is provided by a combustion air blower. The external combustion internal heat dry distillation furnace is provided with a preheating, drying, dry distillation and cooling four-stage structure, and the cold flue gas generated in the drying section is conducted to the cooling section through the cold flue gas pipeline, and then guided through the exhaust gas pipeline. Passing to the preheating section, preheating the raw coal in it, making full use of the waste heat in the flue gas, and removing a large amount of flue gas to save energy and environmental protection while cooling the semi-coke. In addition, since the raw coal is pre-heat treated, the water content in the raw coal after the drying treatment is less than 1% by weight, thereby ensuring the dry distillation efficiency. In addition, the waste gas generated during dryness is not used for quenching and cooling treatment, but is quenched and cooled by cold flue gas with main components of carbon dioxide and nitrogen. The chemical properties of the flue gas are stable, and the occurrence of danger is minimized. The dry coke process of the present invention has a semi-coke yield of 50%; a semi-coke water content of 8 wt% or less; and a waste gas having a calorific value of 1400 KCa l /Nm ³ or more. In other embodiments, the temperature of the preheated coal briquettes in the preheating step is other values in the range of 50-100 °C. The temperature of the coal block subjected to the drying step in the step a is other values in the range of 150-220 °C. The temperature of the retorting treatment in the step b is other values in the range of from 500 to 570 °C. The temperature of the semi-coke subjected to quenching and cooling treatment in the step c is 110-15 (other values in the range of TC. The temperatures in the above technical solutions are the temperatures in the preheating section, the drying section, the dry distillation section, and the cooling section chamber. The temperature range of the above technical solution can meet the requirements of continuous production of semi-coke, and the temperature value in the specific implementation detailed above is the best embodiment, which can achieve the highest production efficiency and is suitable for continuous operation. In other embodiments, the dry product of step b, the specific product type is determined by the temperature process conditions. In addition, in other embodiments, the preheating step may not be provided, and at this time, most of the cold smoke is guided. The cooling section is cooled to the cooling section, which fully utilizes the cold flue gas generated in the process to cool the dry distillation product, thereby improving the overall retorting efficiency; and removing a large amount of flue gas while cooling the retorting product Sulfur, achieving energy saving and environmental protection. Obviously, the above embodiments are merely examples for clarity, but not true Limited way. For ordinary skill in the art, on the basis of the above description may also make changes or other changes in a different form. It is unnecessary and can not be all of the embodiments among the poor.

Claims

An external combustion internal heat type coal retort furnace characterized in that, from top to bottom, a drying section (2) for drying raw coal is obtained, and cold smoke is obtained while drying;

a dry distillation section (3) for dry distillation of the dried raw coal; the raw coal is subjected to dry distillation to form a dry distillation product;

a cooling section (4) for cooling the dry distillation product produced in the dry distillation section by passing the cold flue gas;

The cold flue gas generated by the drying section (2) is conducted to the cold flue gas duct (10) of the cooling section (4).

2. The coal-drying furnace according to claim 1, wherein a preheating section (1) for preheating the raw coal is further disposed above the drying section (2); the cold flue gas After the cooling section (4) is subjected to a cooling treatment, hot flue gas is generated, and the coal pyrolysis furnace is further provided with an exhaust gas duct ( ) for conducting the hot flue gas to the preheating section (1).

3. The coal retort furnace according to claim 2, characterized in that the cold flue gas duct (10) is connected with a circulating power device, which can cause the cold generated in the drying section (2) Flue gas is conducted to the cooling section (4) via the cold flue gas duct (10), and then through the exhaust duct

(12) conducting to the preheating section (1).

The coal retort furnace according to claim 3, wherein the circulating power unit is a circulation fan (9).

The coal retort furnace according to claim 2, characterized in that the cold flue gas duct (10) is connected with a row of excess cold flue gas which is unnecessary for the cooling section (4) Empty channel (13).

6. The coal retort furnace according to claim 2, wherein in the dry distillation section (3) The waste gas outlet is also connected to an aftertreatment system (7) for removing coal tar from the waste gas in the dry section (3).

The coal retort furnace according to claim 6, characterized in that a dry burner (5) is further connected between the flue gas outlet of the aftertreatment system (7) and the drying section (2), It combusts a portion of the gas produced in the aftertreatment system (7) to produce a dry flue gas for the drying process in the drying section (2).

8. The coal retort furnace according to claim 7, characterized in that a dry pipe (11) is further connected between the cold flue gas duct (10) and the flue gas outlet of the dry burner (5) It may mix a portion of the cold flue gas produced in the drying section (2) with the dry flue gas to adjust the temperature of the drying process in the drying section (2).

9. The coal retort furnace according to claim 6, characterized in that a dry distillation burner (6) is further connected between the flue gas outlet of the aftertreatment system (7) and the dry distillation section (3), It may combust a portion of the gas produced in the aftertreatment system (7) to produce dry distillation flue gas for the cognac treatment in the dry distillation section (3).

10. The coal-drying furnace according to claim 9, wherein a connection between a flue gas outlet of the aftertreatment system (7) and a flue gas outlet of the cognac burner (6) is further connected A dry distillation line (14) that can mix a portion of the gas produced in the aftertreatment system (7) with the dry distillation flue gas to adjust the temperature of the retorting treatment in the dry distillation section (3).

The coal retort furnace according to any one of claims 7 to 10, characterized in that the flue gas inlet of the drying burner (5) and/or the dry distillation burner (6) is further connected A combustion air blower (8) for providing combustion air to the dry burner (5) and/or the dry distillation burner (6), respectively.