System for coupling alternative fuel pyrolysis gasification and cement production line

Abstract

The utility model discloses an alternative fuel pyrolysis gasification and cement production line coupling system. The system comprises a decomposing furnace, a smoke chamber, an n-stage raw material preheating system, a pyrolysis gasification device and an ash cooling and conveying system, a raw material distributing device is arranged on a blanking pipe of an (n-1)-stage cyclone cylinder in the n-stage raw material preheating system; an outlet of the raw material distributing device is respectively communicated with a raw material inlet of the decomposing furnace and a hot raw material inlet of the pyrolysis gasification device; the pyrolysis gasification device comprises a suspension section positioned at the upper part, a transition section and a boiling section positioned at the middle part, and an air distribution system and a slag outlet positioned at the lower part; a tertiary air inlet is formed in the side surface of the suspension section, and a flue gas outlet communicated with the decomposing furnace is formed in the upper part; an alternative fuel inlet, a bed material inlet and a hot raw material inlet are respectively formed in the side surface of the middle part; and the slag outlet is respectively communicated with the smoke chamber and the ash cooling and conveying system. According to the utility model, the alternative fuel heat utilization efficiency and fossil fuel substitution rate of the cement kiln can be greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a system of alternative fuel utilization especially to a system of alternative fuel pyrolysis gasification and cement production line coupling. BACKGROUND

[0002] In recent years, using alternative fuel has become an important technical path of carbon emission reduction and cost reduction and efficiency increase in the cement industry, and more and more cement plants begin to use alternative fuel as cement decomposition furnace fuel, partially or completely replacing traditional fossil fuel.

[0003] Alternative fuel gasification technology is to pyrolyze alternative fuel into carbon-containing fly ash and combustible gas, and then send it into the decomposition furnace for combustion. Because the combustible gas and carbon-containing fly ash are more easily combustible, under the driving of high-speed airflow in the decomposition furnace, they can be fully combusted, this technology has little effect on the decomposition furnace, and the alternative fuel is fully combusted. For example, CKK gasification furnace of Haisi and continuous pyrolysis gasification furnace of Jin Yu. But this kind of technology also has some problems: because pyrolysis is an endothermic reaction, in order to maintain the reaction temperature in the furnace (generally ≥ 550℃), low-calorific-value alternative fuel needs a large air-fuel ratio, and needs to send in more air, resulting in problems of low calorific value of combustible gas, low heat utilization rate and large exhaust loss.

[0004] Patent CN201010532911.0 discloses a waste treatment equipment for guiding thermal decomposition gas of waste into a cement decomposition furnace, which has a gasification furnace for generating thermal decomposition gas by gasification of waste, and a gas conveying passage for conveying the generated thermal decomposition gas to the decomposition furnace while keeping the contained carbon and ash intact. The thermal decomposition gas is introduced into the decomposition furnace in a form that does not directly interfere with the main stream of waste gas flow from the sintering furnace or the clinker cooler, preventing it from being scraped off and allowing it to be fully combusted. In this way, the existing cement manufacturing equipment is effectively utilized, and sanitary treatment of waste is realized at low cost. However, the gasification furnace of the patent generates thermal decomposition gas by using air as fluidizing medium, and the pyrolysis gasification process of waste is an endothermic reaction, with a reaction temperature generally ≥ 550℃. The required heat source is obtained through oxidation combustion reaction of part of combustible material and oxygen. In order to maintain the reaction temperature in the furnace, alternative fuel needs a large air-fuel ratio, and needs to send in more air, resulting in problems of low calorific value of combustible gas, low heat utilization rate and large exhaust loss.

[0005] Therefore, how to reduce the air-fuel ratio required by alternative fuel and improve the heat utilization rate is a technical problem to be solved. UTILITY MODEL CONTENTS

[0006] Purpose of the utility model: The purpose of this utility model is to provide a system that couples alternative fuel pyrolysis gasification with a cement production line, making full use of the high-temperature heat source of the cement firing system, reducing the air-fuel ratio required for alternative fuels, and effectively improving the heat utilization efficiency of alternative fuels and the fossil fuel substitution rate of cement kilns.

[0007] Technical Solution: The system of coupling alternative fuel pyrolysis gasification with a cement production line according to this utility model includes a decomposition furnace, a flue, an n-stage raw meal preheating system, a pyrolysis gasification device, and an ash cooling and conveying system. A raw meal distribution device is provided on the feed pipe of the n-1 stage cyclone in the n-stage raw meal preheating system. The outlet of the raw meal distribution device is connected to the raw meal inlet of the decomposition furnace and the hot raw meal inlet of the pyrolysis gasification device. The pyrolysis gasification device includes an upper suspension section, a middle transition section and a boiling section, a lower air distribution system, and a slag outlet. A tertiary air inlet connected to the tertiary air outlet pipe of the decomposition furnace is provided on the side of the suspension section, and a flue gas outlet connected to the decomposition furnace is provided at the top. An alternative fuel inlet, a bed material inlet, and a hot raw meal inlet are provided on the side of the middle section of the pyrolysis gasification device. The slag outlet is connected to the flue and the ash cooling and conveying system.

[0008] The air distribution system includes an air distribution pipe or air distribution plate located at the bottom of the pyrolysis gasification device, and a blower connected to the air distribution pipe or air distribution plate.

[0009] The tertiary air inlet is connected to the suspension section in a swirl-cutting direction.

[0010] The pyrolysis gasification device is a bubbling fluidized bed structure.

[0011] The tertiary air outlet pipeline is equipped with a first air volume regulating valve; the flue gas outlet of the pyrolysis gasification device is equipped with a second air volume regulating valve on the connecting pipeline between the decomposition furnace and the gasification device.

[0012] The slag outlet is connected to the smoke chamber and the ash cooling and conveying system via an ash and slag distribution device.

[0013] The ash and slag distribution device includes an ash discharge valve and a tee connected to the ash discharge valve. The tee outlet has two channels, one leading to the smoke chamber and the other leading to the ash and slag cooling and conveying system.

[0014] Beneficial effects: Compared with the prior art, this utility model achieves the following significant effects:

[0015] (1) the utility model discloses the high temperature raw material of cement firing system as the pyrolysis gasification heat source of alternative fuel, and adopts pyrolysis gasification device to pyrolysis gasification disposal to alternative fuel, and the air-fuel ratio required for pyrolysis gasification device is small, and the combustible gas heat value generated in the pyrolysis gasification process of alternative fuel is high, the whole system produces small flue gas, and the flue gas loss is small, and then the heat utilization rate of alternative fuel is high, and the fossil fuel replacement ratio is high;(2) the upper portion of pyrolysis gasification device is introduced with the pyrolysis gasification flue gas premixed that generates, can improve its burnout rate, reduce the carbon monoxide concentration of preheater outlet of firing system, further improve the heat utilization rate of alternative fuel, can also maintain the internal temperature of pyrolysis gasification device simultaneously, reduce fluidization air volume;(3) the slag outlet of pyrolysis gasification device is connected with the material distribution device, can send ash to the decomposition furnace flue or ash cooling conveying system, and the ash is cooled and conveyed to the raw material batching system or other places, and the alternative fuel with more non-combustible impurities also has certain adaptability;(4) the preheating process of the bed material and hearth of pyrolysis gasification device can utilize high-temperature hot raw material and tertiary air, and external burner is saved, and fossil fuel is saved;(5) pyrolysis gasification device can dispose multiple categories of alternative fuel, and adapt to multiple practical conditions such as complex alternative fuel source, large component fluctuation and large physical and chemical component difference;(6) the system of the utility model can greatly improve the alternative fuel heat utilization efficiency of cement kiln and the fossil fuel replacement rate, and also has certain adaptability for low calorific value inferior alternative fuel. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the structure schematic diagram of the system of alternative fuel pyrolysis gasification and cement production line coupling of the utility model;

[0017] Figure 2 It is the structure schematic diagram of pyrolysis gasification device of the utility model. DETAILED DESCRIPTION

[0018] The utility model will be further described in detail in combination with the drawings of specification.

[0019] As Figure 1 The utility model provides a kind of system of alternative fuel pyrolysis gasification and cement production line coupling, including decomposition furnace 1, flue 2, tertiary air pipe 3, n-grade raw material preheating system, raw material material distribution device 6, pyrolysis gasification device 7, ash material distribution device, ash cooling conveying system 12.

[0020] The lower discharge port of the n-1 stage cyclone 5 in the n stage raw meal preheating system is provided with a raw meal distribution device 6, and the outlet of the raw meal distribution device 6 is respectively communicated with the raw meal inlet of the decomposing furnace 1 and the hot raw meal inlet of the pyrolysis gasification device; the pyrolysis gasification device comprises a suspension section 701 located at the upper portion, a transition section and a boiling section 708 located at the middle portion, a wind distribution system and a slag discharge port 706 located at the lower portion; the side surface of the suspension section is provided with a tertiary air inlet communicated with the tertiary air leading pipeline of the decomposing furnace 1, and the upper portion is provided with a flue gas outlet communicated with the decomposing furnace 1; the side surface of the middle portion of the pyrolysis gasification device is provided with a substitute fuel inlet, a bed material inlet and a hot raw meal inlet; and the slag discharge port is respectively communicated with the smoke chamber 2 and the ash and slag cooling and conveying system 12.

[0021] The decomposing furnace 1 is a decomposing furnace in a conventional new dry cement burning system, the smoke chamber 2 is a smoke chamber in the conventional new dry cement burning system, and the raw meal distribution device 6 is a tee distribution device installed on the discharge pipe of the n-1 stage cyclone 5, that is, the raw meal inlet pipe of the decomposing furnace 1. For the cement burning system adopting a five-stage preheating system, the raw meal distribution device 6 is installed on the discharge pipe of the C4 cyclone, and for the cement burning system adopting a six-stage preheating system, the raw meal distribution device is installed on the discharge pipe of the C5 cyclone. The embodiment is a five-stage preheating system, and the raw meal distribution device 6 is installed on the discharge pipe of the C4 cyclone. The raw meal distribution device 6 divides the preheated raw meal into two paths, one of which is fed into the decomposing furnace 1, and the other of which is fed into the hot raw meal inlet of the pyrolysis gasification device 7.

[0022] The pyrolysis gasification device 7 adopts a bubbling fluidized bed structure, the upper portion is a suspension section 701, the side surface is provided with a tertiary air inlet 710, and the upper portion is a flue gas outlet; the tertiary air inlet 710 is connected to the suspension section 701 in a rotary cutting direction, which is more conducive to mixing with the internal flue gas; the tertiary air inlet 710 is connected by the leading pipeline of the tertiary air pipe 3, and the leading pipeline is provided with a first air volume adjusting valve 4; the flue gas outlet is connected to the decomposing furnace 1, and the connected flue gas pipeline is provided with a second air volume adjusting valve 9; the middle portion 708 of the pyrolysis gasification device is a transition section and a boiling section, and the side surface is respectively provided with a substitute fuel inlet 703, a bed material inlet 702 and a hot raw meal inlet 709; the lower portion 707 of the pyrolysis gasification device is provided with a wind distribution system and a slag discharge port 706; the wind distribution system of the utility model comprises a wind distribution pipe 705 and a blower 8 communicated with the wind distribution pipe 705; and the slag discharge port 706 is connected to the ash distribution device.

[0023] The ash and slag distributing device comprises an ash valve 10, the ash valve 10 plays a sealing role, a tee joint 11 is connected behind the ash valve, two passages are divided at the outlet of the tee joint 11, one passage is connected to a smoke chamber 2, and the other passage is connected to an ash and slag cooling and conveying system 12.

[0024] The ash and slag cooling and conveying system 12 is used for cooling the ash and slag and conveying the ash and slag to a raw material batching station to participate in cement raw material batching or to other places for comprehensive utilization.

[0025] The process flow of the system is as follows:

[0026] Bed material is filled into a bed material inlet 702 of a pyrolysis gasification device 7, high-temperature hot raw material of about 800 DEG C of a C4 cyclone is introduced into a middle part 708 of the pyrolysis gasification device through a raw material distributing device 6 from a hot raw material inlet 709, under the driving of fluidized air of a wind distribution system, the high-temperature hot raw material exchanges heat with the bed material, after the temperature of the middle part of the pyrolysis gasification device is increased, substitute fuel is fed into the pyrolysis gasification device 7 from a substitute fuel inlet 703, the substitute fuel, the high-temperature hot raw material, the fluidized air and the heat-stored bed material are fully mixed, rapid heat and mass transfer reactions occur, the substitute fuel is rapidly pyrolyzed and gasified, the pyrolysis gasification reaction temperature is 300-800 DEG C, combustible gas and carbon-containing fly ash are produced, and the hot raw material is introduced into a suspension section 701; in the suspension section 701 of the upper part of the pyrolysis gasification device 7, the combustible gas and the carbon-containing fly ash meet high-temperature gas from a three-time air pipe 3, are rapidly combusted and heat-released, and the hot raw material reaches a decomposition temperature and is decomposed and heat-absorbed. Carbon dioxide produced when calcium carbonate in the hot raw material is decomposed is consumed by reducing molecules such as hydrogen and methane produced by pyrolysis and gasification of the substitute fuel, so that the decomposition of calcium carbonate is effectively promoted in a positive direction, the generation of calcium oxide is promoted, and the temperature during the decomposition of calcium carbonate can be reduced; the flue gas, ash, unreacted combustible gas, carbon-containing fly ash and hot raw material produced finally by the pyrolysis gasification device 7 are introduced into a decomposition furnace 1 from a flue gas outlet 711 of the pyrolysis gasification device 7; the combustible gas and the carbon-containing fly ash continue to combust and heat-release in the decomposition furnace 1 to meet oxygen, and further replace part of fuel coal.

[0027] The unreacted part of the alternative fuel, such as the refractory and large-sized organic matters, is further pyrolyzed and gasified under the scouring and high-temperature environment of the fluidized bed material and raw material until the reaction is complete; the impurities and heavy non-combustible materials mixed in the alternative fuel fall into the lower part of the pyrolysis gasification device 7 and are discharged from the slag outlet 706 of the pyrolysis gasification device 7; the ash and slag discharged from the slag outlet 706 enter the ash and slag distribution device, and the destination of the ash and slag is determined according to the amount, composition and influence on the stable operation of the cement clinker firing system: when the influence of the ash and slag directly entering the decomposition furnace on the stable operation of the cement clinker firing system is acceptable, the ash and slag distribution device sends the ash and slag into the decomposition furnace 1; otherwise, the ash and slag distribution device sends the ash and slag into the ash and slag cooling and conveying system 12. The ash and slag cooling and conveying system 12 is used for cooling and conveying the ash and slag to the raw material batching station to participate in the batching of the cement raw material or other places for comprehensive utilization.

[0028] Temperature control of the middle part 708 of the pyrolysis gasification device: when the temperature of the middle part 708 is too high, the feeding amount of the hot raw material is increased to control the temperature in the incinerator by heat absorption of the decomposition of the hot raw material; when the temperature of the middle part 708 is too low, the air supply amount of the air distribution system is increased; the inlet of the air blower 8 of the air distribution system is connected to a certain amount of air or oxygen-enriched gas, which is pressurized and then sent to the air distribution pipe 705 through the fluidized air inlet 704. The oxygen in the fluidized air generated by the air distribution pipe 705 reacts with the alternative fuel to generate heat to ensure the pyrolysis gasification reaction temperature of the middle part 708 of the pyrolysis gasification device, so that the temperature is always at the appropriate pyrolysis gasification temperature for various alternative fuels.

[0029] Temperature control of the upper suspension section 701 of the pyrolysis gasification device 7: when the temperature of the upper suspension section 701 is too high, the opening of the first air volume adjusting valve 4 is reduced to reduce the feeding amount of the tertiary air; when the temperature of the upper suspension section 701 is too low, the opening of the first air volume adjusting valve 4 is increased to increase the feeding amount of the tertiary air.

[0030] Pressure control of the inside of the pyrolysis gasification device 7: the flue gas access point of the pyrolysis gasification device 7 is connected to the upper part of the decomposition furnace 1 as much as possible, and the flue gas speed and pressure entering the pyrolysis gasification device 7 are controlled mainly by adjusting the opening of the second air volume adjusting valve 9; if necessary, the feeding amount of the alternative fuel and the air supply amount of the air blower 8 are adjusted to adjust the gas production amount of the pyrolysis gasification reaction, which can also play a role in adjusting the internal pressure of the pyrolysis gasification device 7.

[0031] The bed material of the pyrolysis gasification device 7 can adopt quartz sand or screened slag, and the bed material is fed through a bed material feeding port 702. The air supply fan 8 of the pyrolysis gasification device 7 can blow in air, oxygen-enriched gas and flue gas discharged from a first-stage preheater of the raw meal preheating system. For high-calorific-value alternative fuels, pyrolysis gasification can be completed only by means of high-temperature hot raw meal and tertiary air, and the fluidizing air is only used to maintain the fluidized state of the bed material. At this time, the air supply fan 8 is used to send the flue gas discharged from the first-stage preheater of the raw meal preheating system of the cement firing system into the pyrolysis gasification device 7. For low-calorific-value and low-quality alternative fuels that are difficult to burn, pyrolysis gasification cannot be completed only by means of high-temperature hot raw meal and tertiary air, and the fluidizing air is used to maintain the fluidization of the bed material and provide oxygen. At this time, the air supply fan 8 blows in air or oxygen-enriched gas.

Claims

1. A system for coupling a pyrolysis gasification of a substitute fuel to a cement production line, characterized in that, The application relates to a new type of cement production system, which comprises a decomposing furnace (1), a smoke chamber (2), an n-stage raw material preheating system, a pyrolysis gasification device (7) and an ash and slag cooling and conveying system (12); a raw material distributing device (6) is arranged on the discharging pipe of an n-1 stage cyclone (5) in the n-stage raw material preheating system, the outlet of the raw material distributing device (6) is communicated with the raw material inlet of the decomposing furnace (1) and the hot raw material inlet (709) of the pyrolysis gasification device (7) respectively; the pyrolysis gasification device (7) comprises a suspension section (701) arranged at the upper part, a transition section and a boiling section arranged at the middle part (708), a wind distribution system arranged at the lower part (707) and a slag outlet (706); the side surface of the suspension section (701) is provided with a tertiary air inlet (710) communicated with the tertiary air leading pipeline of the decomposing furnace (1), and the upper part is provided with a flue gas outlet (711) communicated with the decomposing furnace (1); the side surface of the middle part (708) of the pyrolysis gasification device is respectively provided with a substitute fuel inlet (703), a bed material inlet (702) and a hot raw material inlet (709); the slag outlet (706) is communicated with the smoke chamber (2) and the ash and slag cooling and conveying system (12) respectively.

2. The system for coupling a gasifier for pyrolysis of alternative fuels with a cement production line according to claim 1, characterized in that, The wind distribution system comprises a wind distribution pipe (705) or a wind distribution plate arranged at the lower part (707) of the pyrolysis gasification device, and a blower (8) connected with the wind distribution pipe (705) or the wind distribution plate through a fluidizing air inlet (704).

3. The system for coupling a fuel gasifier to a cement production line according to claim 1, wherein, The tertiary air inlet (710) is connected with the suspension section (701) in a rotary cutting direction.

4. The system for coupling a fuel gasifier to a cement production line according to claim 1, wherein, The pyrolysis gasification device (7) is a bubbling fluidized bed structure.

5. The system for coupling a fuel gasifier to a cement production line according to claim 1, wherein, A first air volume adjusting valve (4) is arranged on the tertiary air leading pipeline; a second air volume adjusting valve (9) is arranged on the connecting pipeline between the flue gas outlet (711) of the pyrolysis gasification device (7) and the decomposing furnace (1).

6. The system for coupling a gasification of a substitute fuel pyrolysis with a cement production line according to claim 1, characterized in that, The slag outlet (706) is communicated with the ash and slag cooling and conveying system (12) through an ash and slag distributing device.

7. The system for coupling a fuel gasifier to a cement production line according to claim 6, wherein, The ash and slag distributing device comprises an ash discharging valve (10) and a tee joint (11) connected with the ash discharging valve (10), the outlet of the tee joint (11) is provided with two channels, one of which is connected with the smoke chamber (2) and the other of which is connected with the ash and slag cooling and conveying system (12).

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