Production technology for using furnace method carbon black tail gas as tank method carbon black carrier gas

Abstract

The invention relates to a production technology for using furnace method carbon black tail gas as tank method carbon black carrier gas. The invention belongs to the technical field of tank method carbon black production, relates to a production method capable of recycling clean energy, saving energy and reducing consumption, solves the defect that the cost of carrier gas (natural gas) in the existing tank method carbon black production technology is too high, and provides a method for replacing part of the natural gas used for producing the carrier gas by using furnace method carbon black by using tail gas generated by furnace method carbon black. A part of tail gas is taken from an outlet of a furnace-process carbon black tail gas pressurizing fan, is subjected to washing desulfurization, is cooled by a tubular cooler, and is finally further cooled and dewatered by a screw cooler, so that 99% of water in the tail gas is removed, and the original low-calorific-value tail gas is changed into a high-calorific-value clean energy which is applied to tank-process carbon black production and is used as a part of carrier gas (natural gas); the method solves the problem of too high cost of the tank-method carbon black natural gas, and meanwhile, the method is clean energy recycling, and reduces the energy consumption of the tank-method carbon black.

Description

Technical Field

[0001] This invention belongs to the field of channel black production technology and is a production method that utilizes clean energy and saves energy and reduces consumption. Background Technology

[0002] Channel black production uses anthracene oil as raw material and natural gas or coke oven gas as a carrier gas. The gas is vaporized in a vaporization kettle or tower, mixed with the carrier gas, and then enters a combustion chamber. Through a specially designed burner, it burns in contact with air, pyrolyzing to produce carbon black. Air entering through the bottom damper of the combustion chamber is sent to the main bag filter for collection and separation by a flue gas fan. The flue gas, mainly composed of air with small amounts of CO2, NOx, and sulfur compounds, is discharged through the vent chimney from the main bag filter. The oxygen content in the flue gas is >16%. The carbon black collected in the main bag filter enters the air conveying pipeline through an airtight valve and is then sent to the collection bag filter by a blower for further collection and separation. The collected carbon black enters a dry granulator to convert powdered carbon black into granular carbon black. The granular carbon black is then screened and magnetically separated before being conveyed by an elevator to the finished product silo, where it is packaged by a granular packaging machine. Its fuel source is primarily natural gas, with methane as the main component, hence it is also known as natural gas channel black or gas channel black. Due to the very low yield of channel black and rising natural gas prices, the cost of channel black is too high, making it uneconomical. Channel black is produced by combustion and pyrolysis in contact with air under oxygen-rich conditions. It has a large number of functional groups on its surface, low surface polarity, good dispersibility, good blackness, and good flowability—superior properties that furnace black cannot match. It is mainly used in the paint, ink, and coating industries. Summary of the Invention

[0003] This invention addresses the high cost of existing channel black production technology by utilizing the tail gas from furnace black production to replace a portion of the natural gas used in channel black production. This allows for the reuse of energy from furnace black tail gas, solving the problem of high natural gas costs in channel black production and representing a clean energy reuse process. It also reduces energy consumption in channel black production. To achieve the above objectives, this invention is implemented through the following technical solution. The tail gas produced by the furnace black production line has the following composition (volume %): CO 11.79%, CnHm 6.25%, H2 3.45%, N2 39.48%, CO2 1.44%, O2 0.31%, H2O 37.25%, SO2 0.023%. The carbon black tail gas discharged from the top of the main bag filter (1) of the furnace carbon black process is taken by the tail gas pressurizing fan (2) and a portion of the tail gas is taken into the washing and desulfurization tower (3). After passing through the NaOH aqueous solution tank (4) and being pressurized by the alkali pump (5), the alkali solution is pumped into the desulfurization washing. The alkali solution is atomized by a solid V-cone nozzle. The atomized alkali solution washes the tail gas at about 200°C to remove SO2 from the tail gas. The dust in the exhaust gas passes through the tube cooler group (6). The cooling water is pumped from the circulating water pool into the tube cooler group by the circulating cooling water pump (8). The heated water is cooled down by the cooling tower (7), thereby realizing the long-term circulation operation of the entire system. The exhaust gas is further cooled by passing through the screw cooler (9) to further cool down and remove water, so that the water content of the exhaust gas reaches <1%c. The impurities in the exhaust gas are removed by the high-precision gas filter. The exhaust gas enters the tank carbon black vaporization kettle (11) or vaporization tower through the shut-off valve, regulating valve (10), blind plate valve and flame arrester. The flow rate is adjusted by the regulating valve to control the flow rate within the process requirements.

[0004] Preferably, the exhaust gas is the exhaust gas produced during furnace carbon black production.

[0005] Preferably, the exhaust gas treatment is a tube-and-tube indirect circulating water cooling system.

[0006] Preferably, the exhaust gas dehydration is performed by using waste heat from the production line to freeze and dehydrate the exhaust gas through a screw chiller unit.

[0007] Preferably, the exhaust gas flow rate is automatically adjusted by the DCS system regulating valve.

[0008] The beneficial effects of this invention compared to the prior art are as follows: 1. This invention removes moisture from the tail gas of furnace carbon black production by washing, cooling, and deep cooling, resulting in a clean energy source that can be used directly. This energy source replaces a portion of the carrier gas required for channel carbon black production—natural gas—reducing the amount of natural gas consumed in channel carbon black production, achieving clean production, and reducing energy consumption.

[0009] 2. This invention treats the tail gas from furnace black production, significantly increasing its calorific value to meet the quality requirements of a clean energy source, thereby enhancing the added value of the tail gas and creating greater economic benefits for the company.

[0010] 3. By adjusting the ratio of exhaust gas to natural gas, the required calorific value of the mixed gas can be arbitrarily adjusted. This allows for the adjustment of the carrier gas with different calorific values ​​according to the quality requirements of channel black, ensuring the stability of carbon black production quality. This enables the production of channel black with varying quality requirements, meeting market demands for different grades of channel black. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the exhaust gas generated in a furnace black production line. In the diagram, 1 is the main bag filter for furnace black and 2 is the furnace exhaust gas pressurizing fan.

[0012] Figure 2 This is a schematic diagram of the cooling, purification, desulfurization, and water removal of tail gas from furnace carbon black production. In the diagram, 3 is the tail gas desulfurization scrubbing tower, 4 is the NaOH alkali solution pool, 5 is the alkali pump, 6 is the tube cooler group, 7 is the cooling tower, and 8 is the circulating cooling water pump.

[0013] Figure 3 This is a schematic diagram illustrating how the tail gas from furnace carbon black is precisely adjusted to serve as the fuel gas for trough carbon black; where 9 is a screw cooler, 10 is a pneumatic regulating valve for the tail gas, and 11 is a trough gasification reactor.

[0014] Figure 4 This is a schematic diagram of using the tail gas from furnace black as fuel for trough black; where 1 is the main bag filter for furnace black, 2 is the furnace tail gas pressurizing fan, 3 is the tail gas desulfurization scrubbing tower, 4 is the NaOH alkali tank, 5 is the alkali pump, 6 is the tube cooler group, 7 is the cooling tower, 8 is the circulating cooling water pump, 9 is the screw cooler, 10 is the tail gas pneumatic regulating valve, and 11 is the trough gasification kettle. Detailed Implementation

[0015] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0016] (I) Introduction to main production processes and technologies There are many processes for producing carbon black, and the preparation methods vary depending on the different performance requirements of different fields, especially due to economic factors such as production costs. Among the more mature carbon black production methods are the tank process, furnace process, and pyrolysis process.

[0017] 1. Trench method The channel black process uses natural gas as feedstock. Through specially designed burners, the gas is burned in contact with air within a combustion chamber. The flame then contacts a slowly reciprocating channel steel, causing carbon black to deposit on the steel and be collected. Because its main feedstock is natural gas, primarily composed of methane, it is also known as natural gas channel black or gas channel black. However, the yield of channel black produced using this method is very low, and rising natural gas prices have made it economically unviable. Furthermore, the air pollution problems caused by channel black production cannot be economically resolved, leading to its discontinuation both domestically and internationally.

[0018] 2. Oil furnace method The furnace process uses coal tar or petroleum oil as raw materials, with an appropriate amount of air supplied. The mixture is burned and pyrolyzed at a certain high temperature in a specially designed reactor. The resulting carbon black is suspended in the flue gas, then cooled and collected by a main bag filter. The powdered carbon black is collected through the filter bags and enters the air conveying system from the cone through an airtight valve. The carbon black tail gas is discharged from the top of the bag filter and sent to the gas boiler of the power plant as fuel by the tail gas pressurization fan to generate steam for power generation. Example

[0019] Open the valve on the pipeline from the outlet of the furnace black tail gas pressurization blower into the tail gas desulfurization scrubbing tower to introduce the tail gas into the desulfurization scrubbing tower. Prepare a 10% NaOH alkali solution in the NaOH alkali tank, start the alkali pump, and scrub the tail gas in the desulfurization scrubbing tower. The scrubbed tail gas then enters the tube cooler group, where water pumped out by the circulating cooling water pump indirectly exchanges heat with the tail gas. The tail gas is cooled, and the circulating water is heated. The heated circulating water passes through the cooling tower, where the heat of the circulating water directly exchanges heat with the air entering from the bottom of the cooling tower. The air dissipates the heat from the circulating water into the atmosphere through the exhaust fan at the top of the cooling tower, thus ensuring that the water temperature in the circulating water tank remains within a certain temperature range and ensuring the continuous and stable operation of the entire cooling system. The cooled tail gas then enters a screw cooler for further cooling, ensuring that the moisture content of the tail gas is less than 0.5%. The adjustment parameters for furnace black tail gas as carrier gas in the trough method are as follows: Product C-611, oil flow rate before adjustment: 380 kg / h, natural gas flow rate: 420 Nm³. 3 / h, tail gas flow rate of carbon black produced by gas-fired furnace: 0Nm 3 / h, test results: iodine absorption value: 100g / kg, oil absorption value: 95 ml / 100g, blackness: 37.5, flowability: 25mm, tinting strength: 118%, fineness: 20, carbon black production per hour: 185kg / h. Fuel consumption per ton of carbon black: 2270 Nm³ 3 / h. Adjusted fuel oil flow rate: 350 kg / h, carrier natural gas flow rate: 280 Nm³ / h. 3 / h, tail gas flow rate of carbon black produced by gas-fired furnace: 1000 Nm 3 / h, test results: iodine uptake: 101 g / kg, absorbance: 93 ml / 100g, blackness: 37.2, flowability: 25 mm, tinting strength: 118%, fineness: 20, carbon black production per hour: 187 kg / h. Fuel consumption per ton of carbon black: 1135 Nm³ 3 By using the tail gas from furnace carbon black as carrier gas for trough carbon black, natural gas is saved by 556 Nm3 / h per ton of carbon black. Example

[0020] Open the valve on the pipeline from the outlet of the furnace black tail gas pressurization blower into the tail gas desulfurization and scrubbing tower to introduce the tail gas into the desulfurization and scrubbing tower. Prepare a 10% NaOH alkali solution in the NaOH alkali tank, start the alkali pump, and scrub and desulfurize the tail gas in the desulfurization and scrubbing tower. The scrubbed and desulfurized tail gas enters the tube cooler group, where water pumped out by the circulating cooling water pump indirectly exchanges heat with the tail gas. The tail gas is cooled, and the circulating water is heated. The heated circulating water passes through the cooling tower, where the heat of the circulating water directly exchanges heat with the air entering from the bottom of the cooling tower. The air dissipates the heat from the circulating water into the atmosphere through the exhaust fan at the top of the cooling tower, thus ensuring that the water temperature in the circulating water tank remains within a certain temperature range and ensuring the continuous and stable operation of the entire cooling system. The cooled tail gas enters the screw cooler for further cooling, ensuring that the water content of the tail gas is less than <0.5%. The adjustment parameters for furnace black tail gas as carrier gas in the trough method are as follows: Product: C-311; Pre-adjustment oil flow rate: 300 kg / h; Carrier natural gas flow rate: 550 Nm³ / h. 3 / h, tail gas flow rate of carbon black produced by gas-fired furnace: 0Nm 3 / h, test results: iodine absorption value: 130g / kg, oil absorption value: 92ml / 100g, blackness: 32, flowability: 25.5mm, tinting strength: 125%, fineness: 20, carbon black production per hour: 150kg / b. Gas consumption per ton of carbon black: 3667Nm3 / h. Adjusted anthracene oil flow rate: 300kg / h, natural gas flow rate: 430 Nm3 / h. 3 / h, tail gas flow rate of carbon black produced by gas-fired furnace: 800 Nm 3 / h, test results: iodine absorption value: 129g / kg; oil absorption value: 91ml / 100g; blackness: 32.2; flowability: 25.0mm; tinting strength: 125%; fineness: 2); carbon black production per hour: 153kg / h; fuel gas consumption per ton of carbon black: 1960Nm3 / h. After using furnace carbon black tail gas as fuel gas for channel carbon black production, natural gas savings per ton of carbon black: 856Nm3 / h.

Claims

1. A method for using the tail gas generated by furnace black production to replace a portion of the natural gas used in the carrier of channel black production. The tail gas discharged from the top of the main bag filter (1) of furnace black production is fed into a scrubbing desulfurization tower (3) via a tail gas pressurizing blower (2). After passing through a NaOH aqueous solution tank (4), the alkaline solution is pressurized by an alkali pump (5) and injected into the desulfurization scrubbing tower. The alkaline solution is atomized through a solid V-cone nozzle and used to scrub the tail gas at around 200°C to remove SO2 from the tail gas. The dust in the exhaust gas passes through the tube cooler group (6). The cooling water is pumped from the circulating water pool into the tube cooler group by the circulating cooling water pump (8). The heated water is cooled down by the cooling tower (7), thereby realizing the long-term circulation operation of the entire system and further cooling the exhaust gas. The exhaust gas is further cooled down and dehydrated by the screw cooler (9), so that the water content of the exhaust gas reaches <1%c. The impurities in the exhaust gas are removed by the high-precision gas filter. The gas enters the trough carbon black vaporization kettle (11) or vaporization tower through the shut-off valve, regulating valve (10), blind plate valve and flame arrester. The flow rate is adjusted by the regulating valve to control the flow rate within the process requirements.

2. The production technology of using furnace black tail gas as fuel gas for trough black production according to claim 1, characterized in that... The tail gas generated during furnace black production is used as carrier gas for channel black production.

3. The production technology of using furnace black tail gas as fuel gas for trough black production according to claim 1, characterized in that... The tail gas generated from furnace carbon black production is washed and desulfurized with NaOH to remove SO2 and dust from the tail gas.

4. The production technology of using furnace black tail gas as fuel gas for trough black production according to claim 1, characterized in that... The exhaust gas generated during furnace carbon black production is cooled down by passing through a shell-and-tube heat exchanger, circulating cooling water, and a cooling tower.

5. The production technology of using furnace black tail gas as fuel gas for trough black production according to claim 1, characterized in that... The exhaust gas generated from furnace black production is subjected to deep cooling and dehydration via a screw cooler to ensure that the moisture content of the exhaust gas is less than 1%.

6. The production technology of using furnace black tail gas as fuel gas for trough black production according to claim 1, characterized in that... The exhaust gas generated during furnace carbon black production undergoes multi-stage treatment, transforming it into a clean energy source. Through automatic regulating valves and precise metering, it is mixed with the fuel gas for channel carbon black production in a certain proportion to produce different varieties of high-quality channel carbon black. This significantly reduces the amount of natural gas consumed per ton of channel carbon black, improving the product's economics and greatly saving on natural gas energy consumption.

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