A new treatment process for the closed circulating water system of acetylene black produced from natural gas

Abstract

The invention discloses a novel treatment process for a closed circulating water system of acetylene black prepared from natural gas, belonging to the technical field of acetylene preparation. A novel treatment process for a closed circulating water system of acetylene black prepared from natural gas mainly includes an in-situ circulating water system for a cracking unit, an in-situ circulating water system for a concentration enhancing unit, and a recovery system for carbon black water waste gas; the invention solves the problem that the carbon black water separation process is not affected by the loss of the solvent in the concentration enhancing unit, adopts a closed system treatment process, realizes automatic control, has safe and reliable operation, is convenient to operate, and thus achieves the overall goals that the in-situ circulating carbon black water treatment system meets the requirements of economy, emission reduction, and environmental protection compliance discharge.

Description

Technical Field

[0001] The present invention relates to the technical field of acetylene preparation, and in particular to a novel treatment process for a closed system of circulating water in the production of acetylene black from natural gas. Background Art

[0002] In the process of producing acetylene by partial oxidation of natural gas, a large amount of carbon black water is generated during the cracking reaction. In the existing operating devices, after the carbon black water is treated by the carbon black separation process, it enters the hot water pool together with the concentrated unit's local return water. Then, it is pumped into a hyperbolic cooling tower, cooled by air, and returns to the bottom water tank of the cooling tower, and then flows back to the cold water pool. The water in the cold water pool is pumped to each unit user again.

[0003] The water containing a large amount of carbon black returned from the production device enters a carbon scraping machine for carbon black and water separation. Since the true density of carbon black is 1.5 - 2 times that of water density, carbon black should sink to the bottom. However, due to its high porosity, carbon black contains a large amount of gas, and the carbon black particles have high adsorption, so each particle is surrounded by bubbles, making the actual density of carbon black lower than that of water, resulting in a floating effect, and the carbon black particles float to the surface of the water. Therefore, the carbon black particles float to the surface of the water and are removed, and the water from which carbon black has been removed continues to enter the device for reuse;

[0004] The water returned from the production device to the carbon black water separation system is divided into two parts: flushing carbon black water and system cooling water. Among them, the flushing water of the cracking and compression devices contains trace amounts of organic gases and needs to be degassed. The cooling carbon black water in the concentration unit is in direct contact with the internal process medium of the device, not only absorbing trace amounts of organic matter but also carrying trace amounts of organic solvents. When a large amount of organic solvents enter the carbon black treatment system under abnormal conditions in the concentration unit, it causes the organic solvents in the carbon black circulating water to exceed the standard. When the organic solvents in the carbon black water > 100 mg / kg, due to most of the surface of the porous carbon black being surrounded by bubbles, the water solubility of the carbon black bubbles is reduced, forming foam-type carbon black; as the amount of organic solvents in the local water increases, the carbon black in the carbon black water floats to the water surface faster to form foam-like carbon black, increasing the load of the scraper and even causing the scraper to break, resulting in the device being forced to stop; at the same time, the amount of water that needs to be sent to the sewage treatment plant in the local circulating water system is about 3000 m 3 This is not conducive to the operation requirements of the device and is not conducive to development.

[0005] Moreover, in the existing operating devices, the internal circulating local water and carbon black water in the carbon black water treatment system are prone to excessive accumulation of organic matter in the carbon black water, and the cooling system frequently fails, resulting in problems such as a short operation cycle of the production device and a large amount of maintenance work. Summary of the Invention

[0006] The object of the present invention is to solve the problems raised in the above-mentioned background technology, and a new type of treatment process for the closed circulating water system of acetylene black produced from natural gas is proposed.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A new type of treatment process for the closed circulating water system of acetylene black produced from natural gas mainly includes a local circulating water system for the cracking unit, a local circulating water system for the concentration unit, and a carbon black water waste gas recovery system;

[0009] The local circulating water system of the cracking unit mainly includes: a cracking unit, degassing, a carbon black separation tank, a carbon black pressure filtration device, a local circulating hot water tank for carbon black, a compression unit, and a local circulating cooling group for carbon black. The degassing is used to recover the cracked gas in the carbon black water and discharge the degassed carbon black water into the carbon black separation tank. The local circulating hot water tank for carbon black is used to recover the filtrate in the carbon black separation tank and the carbon black compression device. The carbon black pressure filtration device is used to recover the carbon black in the carbon black separation tank. The local circulating cooling group for carbon black is used to cool the hot water in the local circulating hot water tank for carbon black and then discharge it into the cracking unit;

[0010] The local circulating water system of the concentration unit mainly includes: a concentration unit, a local circulating hot water tank for concentrated carbon black, a local circulating water filter for concentrated carbon black, and a local circulating cooling group for concentrated carbon black. The local circulating hot water tank for concentrated carbon black is used to recover the cooled carbon black water. The local circulating water filter for concentrated carbon black is used to filter the particulate impurities in the carbon black water. The local circulating cooling group for concentrated carbon black is used to cool the filtered carbon black water and then discharge it into the concentration unit;

[0011] The carbon black water waste gas recovery system mainly includes a tail gas collection hood arranged on the carbon black separation tank.

[0012] Preferably, the quenching hot water with a temperature higher than 75 °C in the carbon black separation tank enters the cracking unit.

[0013] Preferably, the local circulating cooling group for carbon black includes a local circulating water filter for carbon black, a local circulating cooler for carbon black, and a local circulating cryogenic cooler for carbon black which are connected in sequence.

[0014] Preferably, the carbon black at 40 - 50 °C discharged from the local circulating cooler for carbon black is discharged into the local circulating hot water tank for concentrated carbon black.

[0015] Preferably, the local circulating cooling group for concentrated carbon black includes a local circulating cooler for concentrated carbon black and a local circulating cryogenic cooler for concentrated carbon black which are connected in sequence.

[0016] Preferably, it further includes a carbon black wastewater overflow tank and a carbon black wastewater integrated purifier. The carbon black wastewater overflow tank is used to recover the overflow water in the carbon black in-situ circulating hot water tank and the concentrated carbon black in-situ circulating hot water tank, and discharge the overflow water into the carbon black wastewater integrated purifier.

[0017] Preferably, the filtered carbon black slurry in the carbon black wastewater integrated purifier is discharged into a carbon black filter press device, and part of the carbon black wastewater in the carbon black wastewater integrated purifier is sent to the purified carbon black in-situ circulating hot water tank or the carbon black in-situ circulating hot water tank.

[0018] Preferably, multiple groups of carbon black separation tanks are provided, and the multiple groups of tail gas collection hoods are connected through pipelines.

[0019] Preferably, the exhaust ends of the carbon black in-situ circulating water tank, the concentrated carbon black in-situ circulating water tank, and the carbon black wastewater overflow tank are connected through pipelines.

[0020] Preferably, inert gas is introduced into the carbon black in-situ circulating water tank, the concentrated carbon black in-situ circulating water tank, and the carbon black wastewater overflow tank.

[0021] Compared with the prior art, the present invention provides a new type of treatment process for a closed system of circulating water for natural gas to acetylene carbon black, having the following beneficial effects:

[0022] For the parts not involved in this device, they are the same as or can be implemented by the prior art. The present invention solves the problem that the carbon black wastewater separation process is not affected by the solvent loss in the concentration unit. By adopting a closed system treatment process, it realizes automatic control, reliable operation, convenient operation, and thus achieves the overall goals of the in-situ circulating carbon black water treatment system being economical, emission reduction, and environmental protection up to standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a new type of treatment process for a closed system of circulating water for natural gas to acetylene carbon black proposed by the present invention Figure 1 ;

[0024] Figure 2 is a schematic enlarged structural diagram of part A in a new type of treatment process for a closed system of circulating water for natural gas to acetylene carbon black proposed by the present invention Figure 1 ;

[0025] Figure 3 is a schematic enlarged structural diagram of part B in a new type of treatment process for a closed system of circulating water for natural gas to acetylene carbon black proposed by the present invention Figure 1 ;

[0026] Figure 4 is a schematic structural diagram of a new type of treatment process for a closed system of circulating water for natural gas to acetylene carbon black proposed by the present invention Figure 2 。 Detailed implementation mode

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0028] Embodiment:

[0029] Refer to Figures 1-4 , a treatment process for a closed circulating water system of a new natural gas to acetylene carbon black, mainly including a local circulating water system for the cracking unit, a local circulating water system for the concentration unit, and a carbon black water and waste gas recovery system;

[0030] The local circulating water system of the cracking unit mainly includes: a cracking unit, degassing, a carbon black separation tank, a carbon black pressure filtration device, a local circulating hot water tank for carbon black, a compression unit, and a local circulating cooling group for carbon black. Degassing is used to recover the cracked gas in the carbon black water and discharge the degassed carbon black water into the carbon black separation tank. The local circulating hot water tank for carbon black is used to recover the filtrate in the carbon black separation tank and the carbon black compression device. The carbon black pressure filtration device is used to recover the carbon black in the carbon black separation tank. The local circulating cooling group for carbon black is used to cool the hot water in the local circulating hot water tank for carbon black and then discharge it into the cracking unit. The local circulating cooling group for carbon black includes a carbon black local circulating water filter, a carbon black local circulating cooler, and a carbon black local circulating deep cooler connected in sequence;

[0031] During the production of acetylene, the water containing a large amount of carbon black and resin during the quenching and washing of the cracked gas is collected into the local circulating return water pipe network and then enters the local circulating water system of the cracking unit through the main pipe;

[0032] After the carbon black water is degassed in the degassing tower, the carbon black water is distributed and sent into multiple carbon black separation tanks to separate the carbon black in the carbon black water. The separated carbon black with a water content of more than 95% is sent into the carbon black pressure filtration device for re-dehydration. After pressure filtration, the water content of the carbon black filter cake is less than 50%. The carbon black after pressure filtration is sent to the carbon black by-product resource utilization device through a screw conveyor for drying and processing into products for sale, while the filtrate in the carbon black pressure filtration device is recovered and returned to the local circulating hot water tank for carbon black;

[0033] Among them, the quenching hot water with a temperature higher than 75°C in the carbon black separation tank enters the cracking unit,

[0034] The carbon black water after being treated in the carbon black separation tank has a carbon black concentration not exceeding 40 g / m3. Part of the treated hot water is sent to the acetylene furnace as quenching water, and the remaining part is sent to the local circulating cooling hot water tank for carbon black;

[0035] The local circulating hot water tank for carbon black is equipped with an overflow port. When the carbon black water overflows the overflow port, it overflows into the carbon black overflow tank. To ensure that the pH of the carbon black water in this system is on the low side and causes corrosion to pipeline equipment, ammonia water with a concentration of 30% is continuously added to this tank for adjustment;

[0036] The carbon black water in the local circulating hot water tank for carbon black is pumped to the local circulating water filter for carbon black to remove larger particle impurities in the carbon black water. It is cooled to 30 - 35 °C through the local circulating cooler for carbon black and the local circulating cryogenic cooler for carbon black, and is respectively sent to each user in the cracking unit and the compression unit.

[0037] The local circulating water system for the concentration unit mainly includes: the concentration unit, the local circulating hot water tank for concentrated carbon black, the local circulating water filter for concentrated carbon black, and the local circulating cooling group for concentrated carbon black. The local circulating hot water tank for concentrated carbon black is used to recover the cooled carbon black water. The local circulating water filter for concentrated carbon black is used to filter the particle impurities in the carbon black water. The local circulating cooling group for concentrated carbon black is used to cool the filtered carbon black water and then discharge it into the concentration unit. The local circulating cooling group for concentrated carbon black includes the local circulating cooler for concentrated carbon black and the local circulating cryogenic cooler for concentrated carbon black that are connected in sequence;

[0038] The carbon black water in the local circulating water system for the concentration unit is mainly used for the gas phase cooling of the final high - grade acetylene water wash tower and the vacuum ejector. The cooled carbon black water is recycled to the local circulating hot water tank for concentrated carbon black through the return water main pipe;

[0039] An overflow port is provided in the local circulating hot water tank for concentrated carbon black cooling. When the carbon black water exceeds the overflow port, it overflows into the carbon black overflow tank. To ensure that the pH of the carbon black water in this system is on the low side and causes corrosion to pipeline equipment, ammonia water with a concentration of 30% is continuously added to this tank for adjustment;

[0040] The carbon black water in the local circulating hot water tank for concentrated carbon black is pumped to the filter to remove larger particle impurities in the carbon black water. It is cooled to 40 - 45 °C through the local circulating cooler for concentrated carbon black. To ensure the water balance in the cracking unit and the compression unit, a part of the carbon black water is sent to the local circulating tank for concentrated carbon black to improve the water quality of this system. The remaining part is sent to the local circulating cryogenic cooler for concentrated carbon black and cooled to 30 - 35 °C, and then respectively sent to each user in the concentration unit.

[0041] The carbon black water waste gas recovery system mainly includes a tail gas collection hood arranged on the carbon black separation tank. There are multiple groups of carbon black separation tanks, and the multiple groups of tail gas collection hoods are connected through pipelines; the exhaust ends of the local circulating water tank for carbon black, the local circulating water tank for concentrated carbon black, and the carbon black overflow tank are connected through pipelines; inert gas is introduced into the local circulating water tank for carbon black, the local circulating water tank for concentrated carbon black, and the carbon black overflow tank;

[0042] After the carbon black water is degassed in the degassing tower, the carbon black water is distributed and sent into multiple separation ponds. Since the carbon black separation ponds are open-air in the operating device during the carbon black separation process, tail gas collection hoods are installed on the carbon black separation ponds. The gases in several series of ponds are connected through pipelines, and a tail gas induced draft fan is set at the end of the pipeline to draw it out and discharge it to the incinerator for treatment.

[0043] There may be accumulated gases in the closed carbon black in-situ circulation water tank, concentrated carbon black in-situ circulation water tank, and carbon black water overflow tank where the carbon black water from the carbon black separation pond enters. In these closed water tanks, inert gas is continuously introduced, and the possible combustible gases are continuously displaced. Then, through pipeline connection, it is sent to the tail gas induced draft fan together with the gas collected from the separation pond and discharged to the incinerator for treatment.

[0044] Other unorganized emission gases are collected through pipelines and sent to the incinerator for treatment by the tail gas induced draft fan.

[0045] The carbon black discharged at 40 - 50 °C from the carbon black in-situ circulation cooler is discharged into the concentrated carbon black in-situ circulation hot water tank.

[0046] It also includes a carbon black water overflow tank and a carbon black water integrated purifier. The carbon black water overflow tank is used to recover the overflow water in the carbon black in-situ circulation hot water tank and the concentrated carbon black in-situ circulation hot water tank, and discharge the overflow water into the carbon black water integrated purifier.

[0047] The filtered carbon black slurry in the carbon black water integrated purifier is discharged into the carbon black pressure filtration device, and part of the carbon black water in the carbon black water integrated purifier is sent to the concentrated carbon black in-situ circulation hot water tank or the carbon black in-situ circulation hot water tank.

[0048] The present invention solves the problem that the carbon black water separation process is not affected by the solvent loss in the concentration unit. By adopting a closed system treatment process, it realizes automatic control, reliable operation, convenient operation, and thus achieves the overall goals of the in-situ circulation carbon black water treatment system being economical, emission reduction, and meeting environmental protection discharge standards.

[0049] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, should be covered within the protection scope of the present invention.

Claims

1. A treatment process for a closed circulating water system of acetylene black produced from natural gas, characterized in that, It mainly includes the in-situ circulating water system of the cracking unit, the in-situ circulating water system of the concentration unit, and the carbon black water and waste gas recovery system; The in-situ circulating water system of the cracking unit mainly includes: a cracking unit, a degassing unit, a carbon black separation tank, a carbon black pressure filtration device, an in-situ circulating hot water tank for carbon black, a compression unit, and an in-situ circulating cooling group for carbon black. The degassing unit is used to recover the cracked gas in the carbon black water and discharge the degassed carbon black water into the carbon black separation tank. The in-situ circulating hot water tank for carbon black is used to recover the filtrate in the carbon black separation tank and the carbon black pressure filtration device. The carbon black pressure filtration device is used to recover the carbon black in the carbon black separation tank. The in-situ circulating cooling group for carbon black is used to cool the hot water in the in-situ circulating hot water tank for carbon black and then discharge it into the cracking unit; The in-situ circulating water system of the concentration unit mainly includes: a concentration unit, an in-situ circulating hot water tank for concentrated carbon black, an in-situ circulating water filter for concentrated carbon black, and an in-situ circulating cooling group for concentrated carbon black. The in-situ circulating hot water tank for concentrated carbon black is used to recover the cooled carbon black water generated by the concentration unit. The in-situ circulating water filter for concentrated carbon black is used to filter the particulate impurities in the carbon black water. The in-situ circulating cooling group for concentrated carbon black is used to cool the filtered carbon black water and then discharge it into the concentration unit; The carbon black water and waste gas recovery system mainly includes an exhaust gas collection hood arranged on the carbon black separation tank; The in-situ circulating cooling group for carbon black includes a carbon black in-situ circulating water filter, a carbon black in-situ circulating cooler, and a carbon black in-situ circulating deep cooler that are connected in sequence; The carbon black at 40 - 50 °C discharged from the carbon black in-situ circulating cooler is discharged into the in-situ circulating hot water tank for concentrated carbon black; The in-situ circulating cooling group for concentrated carbon black includes a concentrated carbon black in-situ circulating cooler and a concentrated carbon black in-situ circulating deep cooler that are connected in sequence.

2. The treatment process of the closed circulating water system for acetylene carbon black produced from natural gas according to claim 1, characterized in that, The quenching hot water with a temperature higher than 75 °C in the carbon black separation tank enters the cracking unit.

3. The treatment process of the closed circulating water system for acetylene carbon black produced from natural gas according to claim 1, characterized in that, It also includes a carbon black water overflow tank and a carbon black water integrated purifier. The carbon black water overflow tank is used to recover the overflow water in the in-situ circulating hot water tank for carbon black and the in-situ circulating hot water tank for concentrated carbon black, and discharge the overflow water into the carbon black water integrated purifier.

4. The process for treating the closed circulating water system of acetylene black produced from natural gas according to claim 3, characterized in that, The filtered carbon black slurry in the carbon black water integrated purifier is discharged into the carbon black pressure filtration device, and part of the carbon black water in the carbon black water integrated purifier is sent to the in-situ circulating hot water tank for concentrated carbon black or the in-situ circulating hot water tank for carbon black.

5. The process for treating the closed circulating water system of acetylene carbon black produced from natural gas according to claim 3, characterized in that, Multiple groups of the carbon black separation tanks are provided, and the multiple exhaust gas collection hoods are connected through pipelines.

6. The treatment process of the closed circulating water system for acetylene black produced from natural gas according to claim 3, characterized in that, The exhaust ends of the in-situ circulating hot water tank for carbon black, the in-situ circulating hot water tank for concentrated carbon black, and the carbon black water overflow tank are connected through pipelines.

7. The treatment process of the closed circulating water system for acetylene carbon black produced from natural gas according to claim 6, characterized in that, Inert gas is introduced into the in-situ circulating hot water tank for carbon black, the in-situ circulating hot water tank for concentrated carbon black, and the carbon black water overflow tank.

Images