Carbon black tail gas circulating system

Abstract

The invention relates to the technical field of carbon black tail gas treatment, in particular to a carbon black tail gas circulating system. In order to solve the problem that the existing carbon black tail gas contains a large amount of water vapor, the carbon black tail gas circulating system comprises a reaction furnace, and flue gas exhausted from a flue gas outlet of the reaction furnace passes through a secondary quenching pipeline, an air preheater, a high-temperature flue gas preheater, a waste heat boiler, a low-temperature flue gas preheater, an oil preheater and a main bag filter in sequence; a tail gas outlet of the main bag filter is communicated with an inlet pipeline of a tail gas pressurizing fan, an outlet pipeline of the tail gas pressurizing fan is divided into two paths, one path is communicated with a secondary quenching pipeline, the other path is communicated with a tail gas inlet of a low-temperature tail gas preheater, and a tail gas outlet of the low-temperature tail gas preheater is communicated with a tail gas inlet of a high-temperature tail gas preheater; an outlet of the high-temperature tail gas preheater is used for discharging high-temperature tail gas. The steam amount of the tail gas discharged by the system is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon black tail gas treatment, in particular to a carbon black tail gas circulation system. BACKGROUND

[0002] In the technical field of carbon black production, coal gas and air are combusted in a reaction furnace to release heat, promote the fission reaction of carbon black oil, generate carbon black in the reaction section, and release combustible components such as hydrogen and methane, then the first quenching water is sprayed for temperature reduction in the quenching section to terminate the reaction and complete carbon black graphitization and activation in the residence section; the second quenching water is sprayed at the inlet of the high-temperature air preheater for temperature reduction, so that the flue gas temperature entering the high-temperature air preheater is reduced from 1400℃ to 950℃; then the flue gas successively passes through heat exchangers such as the high-temperature air preheater, the waste heat boiler, and the oil preheater for heat exchange, and finally passes through the Venturi tube to spray the third quenching water for temperature reduction to 250℃, reaching the upper limit of the tolerance temperature of the main bag filter; finally, the carbon black powder in the flue gas is separated from the gas by the main bag filter, and the separated gas components contain about 35% water vapor, of which 15% comes from the first quenching water, 15% from the second quenching water, and 5% from the third quenching water; this gas has combustion value for reuse and is called tail gas, which is usually used for combustion power generation.

[0003] Because the tail gas contains a large amount of water vapor, when transported to the next combustion section, the gas is cooled by heat dissipation of the pipeline, causing some water vapor to condense, which can easily corrode the conveying pipeline; at the same time, the tail gas containing a large amount of water vapor has low combustion efficiency when combusted; in addition, the tail gas containing a large amount of water vapor has low conveying efficiency in the conveying pipeline. SUMMARY

[0004] To solve the problem of a large amount of water vapor in the existing carbon black tail gas, the present application provides a tail gas treatment system that can effectively reduce the water vapor in the carbon black tail gas, i.e., a carbon black tail gas circulation system.

[0005] The present application is implemented by using the following technical solutions: The carbon black tail gas circulation system comprises a reaction furnace, the reaction furnace is provided with a fuel delivery port, an air delivery port, a first rapid cooling water delivery port, a carbon black oil delivery port and a flue gas outlet, the flue gas outlet of the reaction furnace is communicated with a flue gas inlet of an air preheater through a second rapid cooling pipeline, an air inlet of the air preheater is communicated with an air delivery pipeline, an air outlet of the air preheater is communicated with the air delivery port of the reaction furnace, flue gas discharged from a flue gas outlet of the air preheater enters a flue gas inlet of an oil preheater in sequence through a high-temperature flue gas preheater, a waste heat boiler and a low-temperature flue gas preheater, the oil preheater is provided with a carbon black oil inlet and a carbon black oil outlet, the carbon black oil outlet of the oil preheater is communicated with the carbon black oil delivery port of the reaction furnace, flue gas discharged from a flue gas outlet of the oil preheater enters a flue gas inlet of a main bag filter through third rapid cooling water, a tail gas outlet of the main bag filter is communicated with an inlet pipeline of a tail gas pressurizing fan, an outlet pipeline of the tail gas pressurizing fan is divided into two paths, one path is communicated with the second rapid cooling pipeline through a first tail gas circulation pipeline, the other path is communicated with a tail gas inlet of a low-temperature tail gas preheater through a second tail gas circulation pipeline, a third regulating valve is arranged on the second tail gas circulation pipeline, a tail gas outlet of the low-temperature tail gas preheater is communicated with a tail gas inlet of a high-temperature tail gas preheater through a third tail gas circulation pipeline, and an outlet of the high-temperature tail gas preheater is used for discharging high-temperature tail gas.

[0006] Principle description: 1) Assuming that the flue gas temperature after carbon black reaction is 1400℃, and the flue gas amount is Q 烟 , the specific heat capacity is about 1J / kg / K; the air preheater inlet flue gas temperature requirement is not higher than 1000℃, and the required amount of 250℃ low-temperature tail gas for reducing the temperature is obtained from the following formula: Q 烟 ×1400×1+Q 低尾 ×250×1=(Q 烟 +Q 低尾 )×1000×1 Q 低尾 =8 / 15×Q 烟 =0.5×Q 烟 From the above formula, 0.5 times Q 烟 of 250℃ tail gas is required to neutralize Q 烟 of 1400℃ carbon black reaction flue gas temperature, so as to achieve the requirement of reducing the carbon black flue gas to the air preheater inlet flue gas temperature, thereby illustrating the feasibility of neutralizing the high-temperature flue gas temperature by the low-temperature tail gas, in actual process engineering, the third regulating valve is controlled to control the amount of flue gas entering the second rapid cooling pipeline, so as to realize the process of neutralizing the high-temperature flue gas temperature by the low-temperature tail gas to realize the function of the second rapid cooling water; 2) Since 0.5 times Q 烟 of 250℃ tail gas is required to neutralize Q 烟The carbon black reaction flue gas temperature, so that the flue gas volume after heat exchange through the oil preheater increases to 1.5Q 烟 To effectively cool down, at least to the cooling effect of the third quenching water in the past, the third quenching water in the application is at most 1.5 times, but due to the reduction of the second quenching water, the water content in the overall tail gas is at least reduced by 12.5%; 3) After the reaction of the reaction furnace, the flue gas temperature is 1400℃, the flue gas temperature entering the high-temperature air preheater is required to be 1000℃, and the contact heat exchange between the 250℃ low-temperature tail gas and the 1400℃ high-temperature flue gas has more cost-effective than indirect heat exchange of the heat exchanger. Because the composition of the tail gas is consistent with the gas composition in the gas-solid mixture flue gas, no extra impurities are added, and no pollution is caused to the carbon black flue gas system, while using the second quenching water method to cool down is equivalent to adding more by-product water vapor to the carbon black flue gas, which increases the pollution degree of the carbon black flue gas.

[0007] Further, the tail gas inlet of the low-temperature tail gas preheater is provided with a first bypass pipeline between the tail gas outlet thereof, a fourth adjusting valve is arranged on the first bypass pipeline, a first thermometer is arranged at the flue gas inlet of the oil preheater, and the fourth adjusting valve is negatively feedback adjusted according to the first thermometer. The heat exchange amount of the low-temperature tail gas preheater is adjusted by adjusting the amount of tail gas entering the low-temperature tail gas preheater, so that the oil temperature of the oil preheater can be controlled.

[0008] Further, the tail gas inlet of the high-temperature tail gas preheater is provided with a second bypass pipeline between the tail gas outlet thereof, a fifth adjusting valve is arranged on the second bypass pipeline, a second thermometer is arranged at the flue gas inlet of the waste heat boiler, and the fifth adjusting valve is negatively feedback adjusted according to the second thermometer. The heat exchange amount of the waste heat boiler is adjusted by adjusting the amount of tail gas entering the high-temperature tail gas preheater, so that the flue gas temperature of the waste heat boiler can be adjusted.

[0009] Further, a second adjusting valve is arranged on the first tail gas circulating pipeline, a third thermometer is arranged at the flue gas inlet of the air preheater, and the second adjusting valve is feedback adjusted according to the third thermometer, that is, the flue gas inlet temperature of the air preheater is adjusted by adjusting the amount of tail gas entering the air preheater.

[0010] Further, a third bypass pipeline is arranged between the air inlet and the air outlet of the air preheater, a first adjusting valve is arranged on the third bypass pipeline, a fourth thermometer is arranged at the air outlet of the air preheater, and the first adjusting valve is negatively feedback adjusted according to the fourth thermometer. The air temperature entering the reaction furnace is adjusted by adjusting the amount of air entering the air preheater, so that the temperature of the reaction furnace can be adjusted.

[0011] The beneficial effects generated by the present application are as follows: 1) the present application utilizes the characteristics of the same medium, neutralizes and cools the high-temperature medium by the low-temperature medium, eliminates the secondary quenching water into the system, and reduces the pollution degree of water vapor to the system; 2) by increasing the high-temperature tail gas heat exchanger and the low-temperature tail gas heat exchanger, the 250 DEG C tail gas is heat exchanged with the flue gas, which not only reduces the flue gas temperature, but also preliminarily preheats the tail gas temperature, realizing a win-win situation; 3) the water vapor content of the discharged tail gas in the present application is reduced, and the tail gas combustion rate is improved during secondary combustion; 4) the water vapor content of the discharged tail gas in the present application is reduced, the steam condensation is reduced, the pipeline corrosion is reduced, and the pipeline life is prolonged; 5) the water vapor content of the discharged tail gas in the present application is reduced, and the waste heat discharge is reduced; 6) the water vapor content of the discharged tail gas in the present application is reduced, and the conveying efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] The drawings incorporated into the specification and forming a part thereof illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without any creative labor under the premise of the drawings.

[0014] Figure 1 The structure diagram of the carbon black tail gas circulating system described in the present application.

[0015] In the figure: 1-reaction furnace, 2-air preheater, 3-high temperature tail gas preheater, 4-waste heat boiler, 5-low temperature tail gas preheater, 6-oil preheater, 7-bag filter, 8-tail gas pressure fan, 9-first regulating valve, 10-second regulating valve, 11-third regulating valve, 12-fourth regulating valve, 13-fifth regulating valve. DETAILED DESCRIPTION

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without any creative labor under the premise of the drawings.

[0017] In the description, it needs to be pointed out that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. It needs to be pointed out that unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0018] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein; obviously, the examples in the description are only part of the examples of the present application, not all examples.

[0019] The specific embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

[0020] As Figure 1 shown, a carbon black tail gas circulation system, comprising a reaction furnace 1, the reaction furnace 1 is provided with a fuel delivery port, an air delivery port, a first time quenching water delivery port, a carbon black oil delivery port, a flue gas outlet, the flue gas outlet of the reaction furnace 1 is communicated with the flue gas inlet of the air preheater 2 through the second time quenching pipeline, the air inlet of the air preheater 2 is communicated with the air delivery pipeline, the air outlet of the air preheater 2 is communicated with the air delivery port of the reaction furnace 1, the flue gas discharged from the flue gas outlet of the air preheater 2 enters the flue gas inlet of the oil preheater 6 in turn after passing through the high-temperature flue gas preheater, the waste heat boiler 4 and the low-temperature flue gas preheater, the oil preheater 6 is provided with a carbon black oil inlet and a carbon black oil outlet, the carbon black oil outlet of the oil preheater 6 is communicated with the carbon black oil delivery port of the reaction furnace 1, the flue gas discharged from the flue gas outlet of the oil preheater 6 enters the flue gas inlet of the main bag filter 7 after the third time quenching water, the tail gas outlet of the main bag filter 7 is communicated with the inlet pipeline of the tail gas booster fan 8, the outlet pipeline of the tail gas booster fan 8 is divided into two ways, one way is communicated with the second time quenching pipeline, the other way is communicated with the tail gas inlet of the low-temperature tail gas preheater 5 through the second tail gas circulation pipeline, the second tail gas circulation pipeline is provided with a third regulating valve 11, the tail gas outlet of the low-temperature tail gas preheater 5 is communicated with the tail gas inlet of the high-temperature tail gas preheater 3 through the third tail gas circulation pipeline, the outlet of the high-temperature tail gas preheater 3 is used for discharging high-temperature tail gas.

[0021] Principle description: 1) Assuming that the flue gas temperature after carbon black reaction is 1400℃, the flue gas quantity is Q 烟, the specific heat capacity is about 1 J / kg / K; the air preheater 2 inlet flue gas temperature requirement is not higher than 1000℃, and the gas amount of 250℃ low temperature tail gas required for reducing the temperature is obtained from the following formula: Q 烟 ×1400×1+Q 低尾 ×250×1=(Q 烟 +Q 低尾 )×1000×1 Q 低尾 =8 / 15×Q 烟 =0.5×Q 烟 From the above formula, 0.5 times Q 烟 of 250℃ tail gas is required to neutralize Q 烟 carbon black reaction flue gas temperature, which achieves the requirement of reducing the carbon black flue gas to the air preheater 2 inlet flue gas temperature, thereby proving the feasibility of neutralizing the high temperature flue gas temperature by low temperature tail gas, and in actual process engineering, by controlling the third regulating valve 11 to control the flue gas amount entering the second quenching pipeline, the function of the second quenching water is realized by neutralizing the high temperature flue gas temperature by low temperature tail gas; 2) Since 0.5 times Q 烟 of 250℃ tail gas is required to neutralize Q 烟 carbon black reaction flue gas temperature, the flue gas amount after heat exchange of the oil preheater 6 is increased to 1.5Q 烟 , in order to effectively reduce the temperature, at least the cooling effect of the previous third quenching water is achieved, and the third quenching water in the present application is at most increased to 1.5 times, but due to the reduction of the second quenching water, the water content in the whole tail gas is at least reduced by 12.5%; 3) Since the flue gas temperature after reaction in the reaction furnace 1 is 1400℃, the flue gas temperature entering the high temperature air preheater 2 is required to be 1000℃, and the contact heat exchange between 250℃ low temperature tail gas and 1400℃ high temperature flue gas has better cost performance than indirect heat exchange in a heat exchanger. Since the composition of the tail gas is consistent with the gas composition in the gas-solid mixture flue gas, no extra impurities are added, and no pollution is caused to the carbon black flue gas system, and the use of the second quenching water method for cooling is equivalent to adding more byproduct water vapor to the carbon black flue gas, which increases the pollution degree of the carbon black flue gas.

[0022] In specific implementation, a first bypass pipeline is arranged between the tail gas inlet of the low temperature tail gas preheater 5 and the tail gas outlet thereof (the low temperature tail gas preheater 5), a fourth regulating valve 12 is arranged on the first bypass pipeline, a first thermometer is arranged at the flue gas inlet of the oil preheater 6, and the fourth regulating valve 12 is negatively fed back adjusted according to the first thermometer. The heat exchange amount of the low temperature tail gas preheater 5 is adjusted by adjusting the amount of tail gas entering the low temperature tail gas preheater 5, so that the oil temperature of the oil preheater 6 is controllable.

[0023] In a specific implementation, the second bypass pipeline is arranged between the tail gas inlet of the high-temperature tail gas preheater 3 and the tail gas outlet of the high-temperature tail gas preheater 3, the fifth regulating valve 13 is arranged on the second bypass pipeline, the flue gas inlet of the waste heat boiler 4 is provided with a second thermometer, and the fifth regulating valve 13 is negatively feedback regulated according to the second thermometer. The heat exchange amount of the waste heat boiler 4 is adjusted by adjusting the amount of tail gas entering the high-temperature tail gas preheater 3, so that the flue gas temperature of the waste heat boiler 4 is adjustable.

[0024] In a specific implementation, the second regulating valve 10 is arranged on the first tail gas circulating pipeline, the flue gas inlet of the air preheater 2 is provided with a third thermometer, and the second regulating valve 10 is feedback regulated according to the third thermometer, that is, the flue gas inlet temperature of the air preheater 2 is adjusted by adjusting the amount of tail gas entering the air preheater 2.

[0025] In a specific implementation, the third bypass pipeline is arranged between the air inlet and the air outlet of the air preheater 2, the first regulating valve 9 is arranged on the third bypass pipeline, the air outlet of the air preheater 2 is provided with a fourth thermometer, and the first regulating valve 9 is negatively feedback regulated according to the fourth thermometer. The air temperature entering the reaction furnace 1 is adjusted by adjusting the amount of air entering the air preheater 2, so that the temperature of the reaction furnace 1 is adjustable.

[0026] In a specific implementation, the first regulating valve 9, the second regulating valve 10, the third regulating valve 11, the fourth regulating valve 12, and the fifth regulating valve 13 are electrically controlled regulating valves, which are convenient for automatic control.

[0027] The above is only a specific implementation of the present application, which enables those skilled in the art to understand or implement the present application. Although the foregoing embodiments are described in detail, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should be covered in the protection scope of the claims.

Claims

1. A carbon black tail gas recycling system, characterized by, The reaction furnace is provided with a fuel delivery port, an air delivery port, a first quenching water delivery port, a carbon black oil delivery port and a flue gas outlet. The flue gas outlet of the reaction furnace is communicated with a flue gas inlet of an air preheater through a second quenching pipeline. The air inlet of the air preheater is communicated with an air delivery pipeline. The air outlet of the air preheater is communicated with the air delivery port of the reaction furnace. The flue gas discharged from the flue gas outlet of the air preheater enters an oil preheater in sequence through a high-temperature flue gas preheater, a waste heat boiler and a low-temperature flue gas preheater. The oil preheater is provided with a carbon black oil inlet and a carbon black oil outlet. The carbon black oil outlet of the oil preheater is communicated with the carbon black oil delivery port of the reaction furnace. The flue gas discharged from the flue gas outlet of the oil preheater enters a main bag filter from a flue gas inlet of the main bag filter through third quenching water. The tail gas outlet of the main bag filter is communicated with an inlet pipeline of a tail gas pressurizing fan. The outlet pipeline of the tail gas pressurizing fan is divided into two paths. One path is communicated with the second quenching pipeline through a first tail gas circulating pipeline. The other path is communicated with a tail gas inlet of a low-temperature tail gas preheater through a second tail gas circulating pipeline. A third adjusting valve is arranged on the second tail gas circulating pipeline. The tail gas outlet of the low-temperature tail gas preheater is communicated with a tail gas inlet of a high-temperature tail gas preheater through a third tail gas circulating pipeline. The outlet of the high-temperature tail gas preheater is used for discharging high-temperature tail gas.

2. The carbon black tail gas recycling system of claim 1, wherein, A first bypass pipeline is arranged between the tail gas inlet and the tail gas outlet of the low-temperature tail gas preheater. A fourth adjusting valve is arranged on the first bypass pipeline. A first thermometer is arranged at the flue gas inlet of the oil preheater.

3. The carbon black tail gas recycling system of claim 2, wherein, A second bypass pipeline is arranged between the tail gas inlet and the tail gas outlet of the high-temperature tail gas preheater. A fifth adjusting valve is arranged on the second bypass pipeline. A second thermometer is arranged at the flue gas inlet of the waste heat boiler.

4. The carbon black tail gas recycling system of claim 3, wherein, A second adjusting valve is arranged on the first tail gas circulating pipeline. A third thermometer is arranged at the flue gas inlet of the air preheater.

5. A carbon black tail gas recycling system as claimed in claim 4, wherein, A third bypass pipeline is arranged between the air inlet and the air outlet of the air preheater. A first adjusting valve is arranged on the third bypass pipeline. A fourth thermometer is arranged at the air outlet of the air preheater.

Images