CN109675404B

CN109675404B - Operation method of VOCs waste gas adsorbent desorption pyrolysis furnace

Info

Publication number: CN109675404B
Application number: CN201910182005.3A
Authority: CN
Inventors: 杨松
Original assignee: Quanzhou Quanteng Machinery Technology Co ltd
Current assignee: Quanzhou quanteng Machinery Technology Co.,Ltd.
Priority date: 2019-03-11
Filing date: 2019-03-11
Publication date: 2021-12-24
Anticipated expiration: 2039-03-11
Also published as: CN109675404A

Abstract

The invention relates to the technical field of environmental protection, in particular to an operation method of a VOCs waste gas adsorbent desorption pyrolysis furnace. The method is characterized in that: starting feeding system to the vertical shaft feed, the adsorbent top-down moves in the vertical shaft under the effect of gravity in succession, annotate the tail gas retrieval and utilization of wind collection box with the emission of flame path and sweep the adsorbent in the vertical shaft, mix through desorption room bottom grate brick with the VOCs waste gas of desorption again and send to pyrolysis chamber oxidation pyrolysis, high temperature flue gas is sent to the pyrolysis chamber through collection flue and is mixed with the VOCs waste gas of desorption, the excessive oxygen in the high temperature flue gas here is with its oxidation pyrolysis, its tail gas flows into the collection box of discharging fume, discharge to the chimney through waste heat recovery again.

Description

Operation method of VOCs waste gas adsorbent desorption pyrolysis furnace

Technical Field

The invention relates to the technical field of environmental protection, in particular to an operation method of a VOCs waste gas adsorbent desorption pyrolysis furnace.

Background

The industrial gaseous pollutants are the main sources of atmospheric environmental pollutants, wherein Volatile Organic Compounds (VOCs) are gaseous pollutants having serious harmful effects on the environment, and are also the sources of occupational disease harmful factors affecting the health of operators in workplaces, and the Volatile Organic Compounds (VOCs) are widely from the chemical industries of paints, coatings, lubricating oils, rubbers and the like. Due to the huge destructive effect on human bodies and natural environment, the state has come out of relevant laws and regulations to strictly control the treatment and discharge of the pollutants. The organic waste gas treatment technology commonly used at present comprises a combustion method, a chemical oxidation method, a chemical absorption method, an adsorption method, a biological method and the like. Because the VOCs waste gas that discharges in the actual production process is the gaseous pollutant of low concentration, usually adopt the adsorption method to administer, but the adsorbent adsorbs behind the VOCs saturation, becomes solid discarded pollutant, and the way of usually using the heating is with its desorption regeneration. The Chinese invention patent (patent application number is 201210077796.1, the patent name is an electric heating type purification filter element for treating large-air-volume VOCs waste gas) discloses an electric heating type purification filter element for treating large-air-volume VOCs waste gas, which comprises a building enclosure and an adsorption bed layer filled in the building enclosure, and is characterized in that: the electric heating type purifying filter element is in a box-type polyhedral structure with a parallel air inlet surface and an air outlet surface, the air inlet surface and the air outlet surface are one or more layers of porous sieve plates or sieve meshes, and the enclosure structure comprises a sealing part and the air inlet surface and the air outlet surface; the adsorption bed layer is formed by compressing and superposing active carbon mesh cloth or porous active carbon fiber cloth through planes, any two opposite end faces or positions close to the two opposite end faces of the adsorption bed layer are provided with an electrode A and an electrode B, current can be introduced into the adsorption bed layer, a galvanic couple is arranged in the adsorption bed layer, and the temperature of the adsorption bed layer is tested in the process of electric heating; or, the appearance of the electric heating type purifying filter element is a cylinder, the enclosure structure consists of an inner cylinder, an end cover and an outer cylinder, the inner cylinder and the outer cylinder are respectively an air inlet surface and an air outlet surface, the inner cylinder is a hollow porous cylinder with one closed end, activated carbon mesh cloth or porous activated carbon fiber cloth is tightly wound on the inner cylinder to form an adsorption bed layer, the outer cylinder is made of one or more layers of net-shaped or porous materials, the end cover is used as an electrode or an electrode A and an electrode B are arranged on the upper end surface and the lower end surface of the adsorption bed layer or close to the upper end surface and the lower end surface of the adsorption bed layer, current can be introduced into the adsorption bed layer, a galvanic couple is arranged in the adsorption bed layer, and the temperature of the adsorption bed layer is tested in the electric heating process; the mesh shape of the activated carbon mesh cloth is circular, oval or polygonal, the inner diameters of any two longitudinally adjacent holes are larger than the hole walls of the two holes, and an adsorption bed layer is formed by adopting a longitudinal tight winding or plane compaction stacking mode; or the inner diameters of any two holes adjacent in the transverse direction are larger than the hole walls, and the adsorption bed layer is formed by adopting a transverse tight winding or plane compaction stacking mode; the porous activated carbon fiber cloth has round, oval or polygonal holes, the inner diameters of any two longitudinally adjacent holes are larger than the hole distance, and an adsorption bed layer is formed by adopting a longitudinal tight winding or plane compaction stacking mode; or the inner diameter of any two adjacent holes in the transverse direction is larger than the hole distance, and the adsorption bed layer is formed by adopting a transverse tight winding or plane compaction stacking mode; or the porous activated carbon fiber cloth has one or more of the shapes of long strips, X shapes, cross shapes, crescent shapes, arc shapes and L shapes, and circularly appears in a row along the longitudinal direction, the projections of any hole and the hole closest to the position in the adjacent row in the longitudinal and transverse directions are overlapped, and the adsorption bed layer is formed by adopting a longitudinal or transverse tightly winding or plane pressing and overlapping mode; or the projections of the holes in the transverse direction are overlapped, the projection length of the holes in the transverse direction is longer than the projection distance between two adjacent holes in the transverse direction in the longitudinal direction, or the projections of the holes in the longitudinal direction are overlapped, the projection length of the holes in the longitudinal direction is longer than the projection distance between two adjacent holes in the longitudinal direction in the transverse direction, and the adsorption bed layer is formed by adopting a mode of alternately and tightly winding the holes in the longitudinal direction and the transverse direction or pressing and overlapping the holes in a plane mode. The Chinese invention patent (patent application number 201510779318.9, patent name a composite VOCs adsorption concentration runner and its use method) discloses a composite VOCs adsorption concentration runner and its use method, which is characterized in that: the device is formed by coaxially and butt-jointing a molecular sieve rotating wheel and a honeycomb activated carbon rotating wheel with the same diameter, wherein the honeycomb activated carbon rotating wheel is positioned at the inlet side of VOCs (volatile organic compounds), each rotating wheel is provided with an adsorption area, a desorption area and a cooling area, a joint of the two rotating wheels is provided with an isolating ring, and the isolating ring is used for isolating the adsorption area, the desorption area and the cooling area of the two rotating wheels, and re-distributing air and reducing the wind resistance; the molecular sieve rotating wheel is obtained by attaching VOCs adsorbent on a honeycomb-shaped rotating wheel body in a spraying, leaching or dipping mode.

The prior art provides a technical solution of an enclosure structure and an electrothermal purification filter element with an air inlet surface and an air outlet surface which are one or more layers of porous sieve plates or adsorption bed layers filled with sieves for treating the actual problem of the large-air-volume VOCs waste gas, but does not provide a solution on how to replace the electrothermal purification filter element in normal production after the VOCs waste gas is saturated; in the second prior art, a technical solution of adsorption, desorption, concentration and combustion of the VOCs waste gas by adopting a molecular sieve rotating wheel and a honeycomb activated carbon rotating wheel is provided for solving the practical problem of VOCs waste gas treatment, and a technical solution of replacing the adsorbent after VOCs waste gas adsorption saturation is undoubtedly feasible by adopting a mechanical rotating wheel method, but the sealing problem must be solved by rotating wheel moving equipment, and particularly the problem of VOCs waste gas leakage caused by sealing failure under the continuous production condition in the rotating wheel replacing process is solved.

Disclosure of Invention

In view of the above problems, the present invention provides a method for operating a desorption pyrolysis furnace for VOCs exhaust gas adsorbent, which comprises:

filling high-alumina ball filler into a flame path in a desorption pyrolysis furnace body, wherein the particle diameter of the high-alumina ball filler is 20-25 mm, conveying an adsorbent to be desorbed to a vertical path in the desorption pyrolysis furnace body through a feeding system, cutting off a smoke collecting path to test the working condition of the desorption pyrolysis furnace body, introducing airflow through an air injection header to blow from a storage tank to the vertical path, and ensuring that the airflow does not flee from the bottom of the vertical path and smoothly flows into a smoke exhaust header through the flame path through grate bricks.

And secondly, building a flame path and a vertical path of the desorption pyrolysis furnace body in a way of being adjacent to each other, dividing the desorption pyrolysis furnace body into an upper region, a lower region, a desorption pyrolysis region and a lower region by a middle partition arch coupon, namely dividing the flame path into an upper chamber, a lower chamber, a pyrolysis chamber and a heat storage chamber, dividing the vertical path into an upper chamber, a lower chamber, a desorption chamber and a sealing chamber, allowing high-temperature flue gas to enter the heating desorption pyrolysis furnace body from a flue collecting channel, keeping the temperature of the high-temperature flue gas at 260-280 ℃, and adjusting the excess air coefficient of the high-temperature flue gas to enable the oxygen content of the high-temperature flue gas to be not lower than 14%.

And step three, starting a feeding system to feed the vertical passage, continuously moving the adsorbent in the vertical passage from top to bottom under the action of gravity, blowing the adsorbent in the vertical passage by the air injection collection box to recycle the tail gas discharged by the flame passage, mixing the adsorbent with the desorbed VOCs waste gas, sending the mixture to the pyrolysis chamber through a grate brick at the bottom of the desorption chamber for oxidative pyrolysis, sending the high-temperature flue gas to the pyrolysis chamber through the smoke collection passage to mix with the desorbed VOCs waste gas, performing oxidative pyrolysis by using excessive oxygen in the high-temperature flue gas, enabling the tail gas to flow into the smoke exhaust collection box, and then discharging the tail gas to a chimney after waste heat recovery.

The inventor finds that the adsorbent is the basis for realizing the adsorption and separation process of the VOCs waste gas, and the adsorbents commonly used in the field of the adsorption and separation of the VOCs waste gas at present mainly comprise molecular sieves, activated carbon, silica-alumina gel, carbon molecules and the like. In the actual use process, the activated carbon is preferably used because of the following characteristics: one is the only industrial adsorbent used to accomplish the separation and purification process that does not require prior moisture removal; secondly, the activated carbon has a very large inner surface, and can adsorb more nonpolar and low-polar organic molecules than other adsorbents; the adsorption heat or bond strength of the three kinds of activated carbon is generally lower than that of other adsorbents, so that the adsorbed molecules are easy to analyze, and the energy consumption of the adsorbents in regeneration is also lower. The waste gas of VOCs generated in the chemical industries of paint, coating, painting, lubricating oil, rubber and the like has high humidity, and typical pollutants such as benzene, paraxylene and carbon tetrachloride are nonpolar and weakly polar organic molecules and need to be adsorbed and purified by adopting activated carbon.

The inventor finds that the VOCs waste gas is generally desorbed and regenerated by a heating method after being adsorbed to saturation by an active carbon adsorbent, and generally can not be regenerated by a mode of directly contacting with high-temperature flue gas, because the ignition point of the active carbon adsorbing the VOCs waste gas is lower, the active carbon is very easy to be oxidized (combusted), the desorption of the active carbon is realized by an indirect heating mode, in a desorption pyrolysis furnace, the desorbed VOCs waste gas is led out to be mixed with the high-temperature flue gas, and pollutant components in the VOCs waste gas, namely organic molecules are oxidized (combusted) to generate CO harmless to the environment₂、H₂O; the activated carbon moves to the chain transmission grate bed, the tail gas discharged after being treated by the VOCs waste gas environment-friendly purification facility is recycled, and the activated carbon is swept and cooled by the tail gas, so that desorption and regeneration of the activated carbon adsorbent are realized.

The inventor finds that the Volatile Organic Compounds (VOCs) generally refer to volatile organic compounds with the melting point lower than room temperature and the boiling point between 50 ℃ and 250 ℃, that is, the desorption temperature of the adsorbent is higher than 250 ℃, the adsorbent must be cooled to reach room temperature after desorption, so that the desorption regeneration process is completed, and the tail gas discharged after being treated by the VOCs waste gas environment-friendly purification facility is recycled as the coolant, so that the tail gas is certainly utilized at a high value and is more economical.

The inventor finds that the VOCs waste gas adsorbent desorption pyrolysis furnace is designed with a flame path and a vertical path, the flame path is used for high-temperature flue gas to flow, the vertical path is used for the adsorbent to move and fall, and the flame path and the vertical path are adjacently built. The middle partition arch coupon divides the desorption pyrolysis furnace body into an upper region and a lower region, namely an upper region desorption pyrolysis region and a lower region heat accumulation region. The corresponding flame path is also divided into an upper chamber and a lower chamber, the lower chamber is a heat storage chamber and is responsible for introducing high-temperature flue gas of the flue collecting channel into the upper chamber, the upper chamber is a pyrolysis chamber and accumulates high-alumina ball particles, the high-temperature flue gas is mixed with the desorbed VOCs waste gas introduced through grate bricks at the bottom of the pyrolysis chamber, the high-temperature flue gas is oxidized and pyrolyzed by excessive oxygen in the high-temperature flue gas, tail gas flows into a smoke exhaust collection box, and the tail gas is discharged to a chimney after waste heat recovery; corresponding perpendicular way of the same reason also divide into two upper and lower rooms, and the lower chamber is the seal chamber, and the effect prevents that the VOCs waste gas of desorption from erecting the way bottom and scurrying, and the upper chamber is the desorption chamber, is connected with feed system, and top-down continuous movement in perpendicular way is said to the adsorbent under the effect of gravity, and feed system includes the storage tank, annotates wind collection box and introduces the tail gas of the emission of flame path and sweeps the adsorbent, mixes with the VOCs waste gas of desorption again and send to pyrolysis chamber oxidation pyrolysis through desorption room bottom grate brick.

The inventor finds that the ignition point of the activated carbon adsorbing the VOCs waste gas is lower, the activated carbon is very easy to be oxidized (combusted), activated carbon desorption is realized by adopting an indirect heating mode, in a desorption pyrolysis furnace, a flame path and a vertical path are adjacently built, high-temperature flue gas flows through the flame path, the activated carbon heating of the vertical path is realized, the desorbed VOCs waste gas is sent to a pyrolysis chamber through a grate brick at the bottom of the desorption chamber for oxidative pyrolysis, the purged airflow comes from the tail gas discharged from the flame path, the tail gas discharged from the flame path is inert gas with lower oxygen content, the activated carbon is ensured not to be oxidized and keep activity, and high-value utilization is realized while the recycling of the tail gas discharged from the flame path reduces pollutant discharge.

Compared with the prior art, the invention at least has the following advantages: firstly, Volatile Organic Compounds (VOCs) generally refer to volatile organic compounds with melting points lower than room temperature and boiling points between 50 and 250 ℃, that is, the desorption temperature of the adsorbent is higher than 250 ℃, the adsorbent must be cooled to reach room temperature after desorption, so that the desorption regeneration process is completed, and the discharged tail gas treated by a VOCs waste gas environment-friendly purification facility is recycled as a coolant, so that the tail gas is certainly utilized at a high value and is more economical; secondly, the activated carbon that has adsorbed VOCs waste gas is lighter, activated carbon is very easily by the oxidation (burning), need adopt indirect heating's mode to realize the activated carbon desorption, in desorption pyrolysis oven, flame path and vertical road are adjacent to build the building, the high temperature flue gas flows through the flame path, the activated carbon heating to the vertical road has been realized, VOCs waste gas after the desorption is sent to pyrolysis chamber oxidation pyrolysis through desorption chamber bottom grate brick, and the air current that sweeps comes from the tail gas of the emission of flame path, and the tail gas of the emission of flame path is the inert gas that oxygen volume is lower, thereby guaranteed that the activated carbon is not by the oxidation and keeps the activity, also realized the high value utilization when the retrieval and utilization of the tail gas of the emission of flame path reduces pollutant emission.

Drawings

Fig. 1 is a schematic structural view of a VOCs waste gas adsorbent desorption pyrolysis furnace operation method in a front view.

Fig. 2 is a schematic view of the arrangement structure of the section a-a of the operating method of the desorption pyrolysis furnace for the VOCs exhaust gas adsorbent of the present invention.

Fig. 3 is a schematic diagram of a partial enlarged structure B of the operating method of the desorption pyrolysis furnace for the VOCs exhaust gas adsorbent according to the present invention.

Fig. 4 is a schematic diagram of a partial enlarged structure C of the operating method of the desorption pyrolysis furnace for the VOCs exhaust gas adsorbent according to the present invention.

1-feeding system 2-storage tank 3-air injection header 4-smoke exhaust header

5-desorption pyrolysis furnace body 6-vertical passage 7-fire passage 8-grate brick 9-middle partition arch coupon

10-a flue collection channel 11-a pyrolysis chamber 12-a desorption chamber 13-a heat storage chamber 14-a sealing chamber.

Detailed Description

The invention is further described with reference to the following detailed description of embodiments and drawings.

As shown in fig. 1, 2, 3 and 4, a method for operating a desorption pyrolysis furnace for VOCs exhaust gas adsorbent is characterized in that: filling high-aluminum ball filler into a flame path 7 in a desorption pyrolysis furnace body 5, wherein the particle diameter of the high-aluminum ball filler is 20-25 mm, conveying an adsorbent to be desorbed to a vertical path 6 in the desorption pyrolysis furnace body 5 through a feeding system 1, cutting off a flue collecting channel 10 to test the working condition of the desorption pyrolysis furnace body 5, introducing airflow through an air injection collecting box 3, blowing from a storage tank to the vertical path 6, and ensuring that the airflow does not flee from the bottom of the vertical path 6 and smoothly flows into a smoke exhaust collecting box 4 through a grate brick 8 through the flame path 7.

And secondly, a flame path 7 and a vertical path 6 of the desorption pyrolysis furnace body 5 are adjacently built, the desorption pyrolysis furnace body 5 is divided into an upper region, a desorption pyrolysis region and a lower region by a middle partition arch coupon 9, the upper region is a desorption pyrolysis region, the lower region is a heat storage region, the flame path 7 is divided into an upper chamber, a lower chamber, a pyrolysis chamber 11 and a heat storage chamber 13, the vertical path 6 is divided into an upper chamber, a lower chamber, a desorption chamber 12 and a sealing chamber 14, high-temperature flue gas enters the heating desorption pyrolysis furnace body 5 from a flue 10, the temperature of the high-temperature flue gas is kept at 260-280 ℃, and the excess air coefficient of the high-temperature flue gas is adjusted to enable the oxygen content of the high-temperature flue gas to be not lower than 14%.

And step three, starting the feeding system 1 to feed the vertical channel 6, enabling the adsorbent to continuously move in the vertical channel 6 from top to bottom under the action of gravity, blowing the adsorbent in the vertical channel 6 by the air injection header 3 to recycle the tail gas discharged by the flame channel 7, mixing with the desorbed VOCs waste gas, sending the mixture to the pyrolysis chamber 11 through a grate brick 8 at the bottom of the desorption chamber 12 for oxidative pyrolysis, sending the high-temperature flue gas to the pyrolysis chamber 11 through a flue gas collecting channel 10 to be mixed with the desorbed VOCs waste gas, carrying out oxidative pyrolysis on the excessive oxygen in the high-temperature flue gas, enabling the tail gas to flow into a smoke exhaust header 4, and then discharging the tail gas to a chimney after waste heat recovery.

Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A VOCs waste gas adsorbent desorption pyrolysis furnace operation method is characterized by comprising the following steps: filling high-alumina ball filler with the particle diameter of 20-25 mm into a flame path in a desorption pyrolysis furnace body, conveying an adsorbent to be desorbed to a vertical path in the desorption pyrolysis furnace body through a feeding system, cutting off a smoke collecting path to test the working condition of the desorption pyrolysis furnace body, introducing airflow through an air injection header to purge the vertical path from a storage tank, and ensuring that the airflow does not flee from the bottom of the vertical path and smoothly flows into a smoke exhaust header through a grate brick through the flame path; secondly, a flame path and a vertical path of the desorption pyrolysis furnace body are adjacently built, the desorption pyrolysis furnace body is divided into an upper region, a lower region, namely a desorption pyrolysis region, and a lower region heat accumulation region by a middle partition arch coupon, the flame path is divided into an upper chamber and a lower chamber, namely a pyrolysis chamber and a heat accumulation chamber, and the vertical path is divided into an upper chamber and a lower chamber, namely a desorption chamber and a seal chamber; starting a feeding system to feed materials to the vertical passage, enabling the adsorbent to continuously move in the vertical passage from top to bottom under the action of gravity, enabling an air injection collection box to recycle and sweep the tail gas discharged by the flame passage through the adsorbent in the vertical passage, mixing with the desorbed VOCs waste gas, sending the mixture to a pyrolysis chamber through a grate brick at the bottom of the desorption chamber for oxidative pyrolysis, sending the high-temperature flue gas to the pyrolysis chamber through a flue collection channel to be mixed with the desorbed VOCs waste gas, performing oxidative pyrolysis on the high-temperature flue gas by using excessive oxygen in the high-temperature flue gas, enabling the tail gas to flow into a smoke exhaust collection box, and then recovering waste heat and then discharging the tail gas to a chimney; the Volatile Organic Compounds (VOCs) are volatile organic compounds with melting points lower than room temperature and boiling points between 50 ℃ and 250 ℃, the desorption temperature of the adsorbent is higher than 250 ℃, the adsorbent must be cooled to reach the room temperature after desorption, so that the desorption regeneration process is completed, the tail gas discharged after being treated by the VOCs waste gas environment-friendly purification facility is recycled as the coolant, and the tail gas is undoubtedly utilized in a high value and is more economical.

2. The method of claim 1 for operating a VOCs waste gas adsorbent desorption pyrolysis furnace, comprising: and (3) enabling the high-temperature flue gas to enter a heating desorption pyrolysis furnace body from a flue collecting channel, keeping the temperature of the high-temperature flue gas at 260-280 ℃, and adjusting the excess air coefficient of the high-temperature flue gas to enable the oxygen content of the high-temperature flue gas to be not less than 14%.