CN1243028A

CN1243028A - Continuous generating moving-bed waste-gas treatment tower and use thereof

Info

Publication number: CN1243028A
Application number: CN 98116973
Authority: CN
Inventors: 王卫民
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-07-29
Filing date: 1998-07-29
Publication date: 2000-02-02
Anticipated expiration: 2018-07-29
Also published as: CN1168528C

Abstract

The invented continuous regeneration moving bed tail-gas treatment tower relates to a filler tower tail-gas treatment equipment. It is characterized by that a filler reaction tower main body is passed through the gas inlet and outlet with shutter structure and fume box, and formed into multipass staged tail-gas channel, and several helical mechanisms with specific function are connected with reaction tower main body orderly to form a moving bed making filler, degassing chemical material and dust produce mixing reaction and implement separation. The metering chemicals-feeding equipment is formed into the regeneration equipment for retaining reaction activity of the filler, and the same time it is used for treating chemical hazardous, material and dust material. Its desulfurizing effect is greater than 90%, and its dust-removing effect is greater than 95%.

Description

Continuous regeneration moving bed waste gas treatment tower and application thereof

The invention relates to a waste gas treatment device of a packed tower, in particular to a waste gas treatment tower device of a continuous regeneration moving bed, which can be used for treating various waste gases.

The operating principle of a typical packed tower flue gas treatment plant is a wet packed scrubber (fig. 1): the main body of the reaction tower adoptsa filler with a certain granularity as a medium, the liquid containing the medicine flows through the filler layer by spraying from top to bottom, a liquid film is formed on the surface of the filler, the gas reacts with the liquid film when passing through the filler layer, and the reaction efficiency is controlled by the gas phase diffusion at the reaction speed and depends on: reactant concentration difference, reaction surface area, mass transfer coefficient and reaction time. Pollution control design manual (U.S. p.n. cheiramikuv. r.a. yangge. huwenlong, 86) tables 25-3 indicate: the device is used for waste gas absorption treatment, the dust removal efficiency of which reaches 95 percent and 98 percent, but is easy to block, is not suitable for gas treatment of dust-containing substances, and generates a large amount of waste water which is difficult to treat.

The purpose of the invention is: a continuous regeneration moving bed waste gas treatment tower device is provided for separating harmful chemicals and dust substances which can generate reaction in various waste gases. The high-efficiency separation effect can be obtained only by a small amount of water, and the blockage can be automatically removed and the wastewater discharge can be avoided.

The purpose of the invention is realized as follows: a container is used as a filling reaction tower main body, spherical inert particulate matter filling is arranged in the reaction tower, the container can adopt a rectangular section structure or a cylindrical jacket structure, a feeding port at the upper part of the reaction tower main body is provided with a feeding distributor which is communicated with a discharging port of a spiral stirring conveyor, the feeding port of the spiral stirring conveyor is communicated with a discharging port at the upper part of another vertical spiral elevator, a feeding portat the lower part of the vertical spiral elevator is communicated with a discharging port of another spiral screening machine, and the feeding port of the spiral screening machine is directly communicated with an outlet at the lower part of the reaction tower main body to. The spiral stirring conveyor is responsible for stirring and mixing the filler in a rotating way; a drug; recycling materials; the liquid is prepared into a degassing medium with reaction activity, and then the degassing medium is sent into a reaction tower, an inert sphere without reaction activity is arranged in the middle of the degassing medium, a medicament with reaction activity is pasted on the surface of the sphere in a pasty manner, a filler moves from top to bottom in the reaction tower by means of gravity and mechanical extrusion force, and enters a spiral sieving machine after the reaction is finished, the action of the spiral sieving machine is to separate a reaction product from the filler by means of friction and collision, simultaneously send the filler into a vertical spiral lifter, and send the filler into a spiral stirring conveyor from bottom to top in the screwing direction of the lifter, so that a new cycle is started. Each screw mechanism can change the circulating speed of the filling material through stepless speed change transmission, thereby changing the mass transfer surface area (the direction is based on figure 2). The regeneration of the reaction activity can be kept only by continuously updating the medicine on the surface of the filler by the following regeneration device, a liquid conveying pipe is arranged on the shell of the spiral stirring conveyor and is communicated with a solution tank through a metering pump; the recycling waste pipe is communicated with a recycling waste bin through a metering conveyor; the new medicine tube is connected with new medicine bin by means of metering conveyer to form a regeneration device capable of making degasified medium retain reaction activity, in the regeneration device the waste material tube is reused, and the new medicine tube is connected with feeding fan by means of air-regulating valve, and adopts wind-force conveying process to simplify structure and prevent blockage. The exhaust gas flow path is constituted by: when the main body of the reaction tower is of a rectangular section structure, the lower section forms two sides of the long side of the tower body, and a waste gas inlet and outlet (a first return stroke) with a shutter is communicated with an inlet and outlet (a second return stroke) with a shutter at the upper section through a smoke box to form a waste gas channel which is segmented up and down. The length of one stroke of waste gas passing through the packing layer (the short side length of the reaction tower body), namely the flow direction passing through the packing bed is suitable for the direction of a small size due to the restriction of fluid resistance, can be determined to adopt a single stroke or multiple strokes according to the load. The moving bed, the regenerating device and the waste gas channel jointly form the whole device of the waste gas treatment tower of the continuous regenerating moving bed. When the device is operated, the degassing medium is ensured to be in dynamic contact with the waste gas all the time, and the advantages are that reaction products which generate mass transfer resistance due to friction and collision on the surface of the degassing medium are continuously removed, high-reactivity medicaments are supplemented, and the surface of the medium always keeps high reactivity. At the upper section of the reaction tower, the surface of the degassing medium is kept in a wet colloid state to be contacted with the flue gas, and the wet reaction similar to that of a wet filler washing tower is generated while dust is intercepted and attached, so that the main stage of finishing the waste gas treatment is provided. When the degassing medium moves from the upper section to the lower section in the reaction tower, the surfacestill keeps certain reactivity, and when the degassing medium is contacted with the waste gas entering from the lower section, semi-dry and semi-wet reaction and dust interception are carried out as the primary stage of waste gas treatment. The water content in the lower section of the reaction tower is gradually evaporated, thereby creating conditions for avoiding the discharge of waste water. Whether the treatment effect is influenced by the reduction of the water consumption of the process (the water consumption of wet desulphurization and dust removal is more than 4-6 liters per cubic meter of flue gas) while keeping the high-efficiency reaction dust removal and avoiding the wastewater discharge can be demonstrated as follows. The reason why some moisture is required for the reaction is: (for example, treating sulfur-containing exhaust gas)

The reaction requires water: 2 × 16 ═ 32Kg/1 MOL.

When the sulfur content of the coal is 3%, the water consumption for the reaction is calculated as follows:

flue gas amount 10.6 cubic meter (standard)/Kg coal

0.03/10.6 ═ 0.00283KG sulfur/cubic meter (standard)

0.00283/64-0.0000442 MOL/cubic meter (standard)

0.0000442 × 32-0.001414 KG (water) per cubic meter (standard) calculation results show that:the amount of water required for the desulfurization reaction is small. The continuous regeneration moving bed adopts a liquid-gas ratio of 0.01-0.02 (KG water/cubic meter flue gas) to ensure the water required by the reaction. Further calculations demonstrate that moisture can evaporate during the reaction. CaO, SO2, 1.2: 1 SO 2: (KG/cubic meter flue gas) 0.00283, CaO [ KG/cubic meter flue gas]0.00291W (ash) [ KG/cubic meter flue gas]0.0056, by weight: the liquor equals 0.5 water H2O (moisture) [ KG/cubic meter of flue gas](0.00283+0.00291+0.0056)/0.5

0.02268 heat of drying: q0.02268 x 620 x 4.1868 (steam enthalpy) 59.03[ KJ]inlet flue gas enthalpy: 229.98[ KJ/cubic meter flue gas](150C) outlet flue gas enthalpy (sensible heat): 229.98-59.03 ═ 170.95 KJ/cubic meter flue gas outlet smoke temperature (estimated from sensible heat) 101.3C analysis shows: the liquid is supplemented with water according to the material ratio of 0.5, so that the water required by the desulfurization reaction can be met, the smoke has enough heat to dry the material water, and no redundant wastewater is discharged. Another reason that the wet process requires more moisture is that: the partial pressure of the removed matter in the liquid phase is reduced, the mass transfer power is improved, the precipitation and the scaling are prevented, and the mass transfer surface area is formed by a liquid water film. The same effect can be achieved by the method adopted by the continuous regeneration moving bed waste gas treatment tower device. The continuous regeneration moving bed waste gas treatment tower device is unit reaction equipment with strong universality, and examples that the device can be used for other waste gas treatment only by changing medicines are listed as follows

Treatment of exhaust gas with medicaments

A strong oxide; basic nitric oxide

Odor of sodium hypochlorite liquid oil

Waste gas containing CL from caustic soda refuse incineration

The expected effects of the continuous regeneration moving bed waste gas treatment tower are as follows: the flue gas desulfurization efficiency is more than 90 percent, the dust removal efficiency is more than 95 percent, the method can be used for flue gas denitrification (adopting strong oxidizer and alkaline medicine), deodorization (adopting sodium hypochlorite liquid), waste gas containing Cl (adopting caustic soda) in garbage incineration and other waste gas treatment, no waste water is discharged, no blockage occurs, and long-term reliable operation can be realized. The document "cinder bed desulfurization dust-removing equipment" (Jishui Li Qiang Ning, pollution control technology, VOl.11 No.117-21) proposes that cinder is used as raw material; lime powder; the device is similar to a continuous regeneration moving bed desulfurizing tower in static state. The experimental results of the device for treating sulfur-containing waste gas are as follows: the amount of coal slag is 100; the lime amount is 10; the water quantity is determined according to the temperature (in the experiment, the water quantity and the lime quantity are 120: 58), and the bed height is more than 100 mm; the air speed of the empty tower is 0.3 m/s; SO2 concentration of 300-450 PPM), the desulfurization efficiency is more than 90 percent, the dedusting efficiency is more than 95 percent, but the desulfurization is generated along with the prolonging of the treatment timeThe mass transfer resistance of the product attached to the surface is increased, and the efficiency is reduced from 98% to 32%. The continuous regeneration moving bed desulfurizing tower can continuously remove the inert substances (reaction products) blocking mass transfer on the surface of the filler by friction and collision because the desulfurizing medium is kept to continuously move, the regeneration device continuously replenishes fresh medicaments to the surface of the filler, the surface always keeps high-concentration reaction active substances, the reaction efficiency is inevitably greatly improved compared with a fixed wet bed filler tower, and the reaction efficiency can not be reduced along with the prolonging of the treatment time. Air pollution control design manual ([ Mei)]PN. Chelereminuv R.A. Yangge Huwenlong translation. 171) states that a SO2 scrubber using lime as an absorbent is to avoid blockage, the pH value should not be more than 8.0, the continuous regeneration moving bed can automatically break the blockage due to the dynamic state of the packing, the medicine can still work normally with the pH value more than 10.0, and the medicine concentration is increased by two timesThe magnitude necessarily increases the reaction efficacy. The calculated wet-type filler scrubbing tower has 4 liters of sprayed water per cubic meter of flue gas (standard), the thickness of the water film passing through the filler is 2 millimeters, and the mass transfer surface area is 2 square meters per cubic meter of flue gas (standard). The continuous regeneration moving bed adopts spherical filler with the diameter of 10MM and the dosage of 0.00017 cubic meters per cubic meter of flue gas (standard). The circulation multiple is 1/hour, the grain size of the medicine material is 0.2MM, and the mass transfer surface area of the colloid porous type is about 2.1 square meters per cubic meter of smoke (standard). Since the mass transfer coefficient is mainly limited by gas phase diffusion, it can be expected that: the mass transfer coefficients of the spray packed tower and the continuous regeneration moving bed degassing tower are similar, and the analysis and calculation result lists are compared as follows: (relative value)

Name of item	Continuous regeneration moving bed	Wet packed scrubbing tower
Name of item	Continuous regeneration moving bed	Wet packed scrubbing tower	Coefficient of mass transfer	1.0	1.0
Area of mass transfer	1.0	1.0	Coefficient of mass transfer	1.0	1.0
Area of mass transfer	1.0	1.0	Mass transfer power	10.0(PH＝10)	2.0-3.0(PH＝8)
Effect	10.0	2.0-3.0	Mass transfer power	10.0(PH＝10)	2.0-3.0(PH＝8)

Description of the drawings: the mass transfer power is expressed by the logarithmic value of the concentration difference, and the concentration difference of 100 times of the mass transfer power is 10 times. The treatment effect can be expressed as: mass transfer coefficient mass transfer area mass transfer power (product) comparison shows that the main reason why the treatment effect of the continuous regeneration moving bed degassing tower is better than that of the wet-type filler scrubbing tower is that: because the surface of the reaction medium can keep high drug concentration without excessive water dilution and precipitation and scaling, the porous active substances on the surface of the filler can form a large reaction surface area like liquid attached to the surface of the fillerThe continuous regeneration moving bed waste gas treatment tower is a moving bed unit reaction device with stronger universality, and can be used for treating various waste gases by only changing medicaments and operation parameters

The continuous regeneration moving bed waste gas treatment tower device provided by the invention is described as follows by combining the attached drawings and the embodiment:

(FIG. 1) is an isometric view of a wet packing scrubber.

(FIG. 1) wherein: the reaction tower comprises an air inlet (1), a flow passing pore plate (2), a filler (3) and a reaction tower main body

(4) An air outlet (5) and a spray pipe (6)

(FIG. 2) is a front view of a continuous regenerating moving bed desulfurizing tower apparatus proposed according to the present invention (wherein the section constituting the moving bed portion is cut without packing).

(FIG. 3) is a cross-sectional view of section A-A, B-B (FIG. 2) taken in cross-section and then recombined (the moving bed outer part is omitted and the packing is filled).

Pair (fig. 2); (FIG. 3) is explained as follows: a reaction tower main body (1), a waste gas lower inlet (2), a waste gas lower outlet (3), a smoke box (4), a waste gas upper inlet (5), a waste gas upper outlet (6), a reaction tower upper feed inlet (7), a spiral stirring conveyor (8), a vertical spiral elevator (9), a spiral screening machine (10), an ash discharge hole (11), a filler (12), a recycling waste bin (13), a medicine bin (14), a metering conveyor (15), a wind power medicine delivery pipe (16), a liquid box (17), a liquid conveying pipe (18), a reaction tower lower discharge port (19), a waste bin (20), a metering pump (22), a spiral stirring conveyor shell (23), an air regulating valve (24), a louver (25) and a feeding distributor (26)

The details of the structure and examples of the continuous regenerative moving bed offgas processing column according to the present invention will be described below with reference to the accompanying drawings (2) and (3):

the device comprises a reaction tower main body (1) with a rectangular cross section, wherein one side of the lower part of the main body is provided with a waste gas lower inlet (2), the opposite side of the main body is provided with a waste gas lower outlet (3) which is communicated with a waste gas upper inlet (5) through a smoke box (4), the opposite side of the main body is provided with a waste gas upper outlet (6), and a gas inlet and a gas outlet are provided with shutters (25) to form a channel of waste gas upper and lower sections. The upper part feed inlet (7) of the reaction tower main body is communicated with the discharge outlet of a spiral stirring conveyor (8), the feed inlet of the spiral stirring conveyor (8) is communicated with the upper part discharge outlet of a spiral elevator (9), the lower part feed inlet of the elevator is communicated with the discharge outlet of another spiral screening machine (10), the feed inlet of the screening machine is communicated with the lower part discharge outlet (19) of the reaction tower main body (1), the spiral mechanism adopts stepless speed change transmission, a filler (12) is placed in the reaction tower main body and each spiral mechanism to form closed circulation to form a desulfurization moving bed, on the outer shell (23) of the spiral stirring conveyor (8), one end close to the feed inlet is provided with a wind power medicine delivery pipe (16), the wind power medicine delivery pipe (16) is communicated with a new medicine bin (14) through a metering conveyor (15), the wind power medicine delivery pipe (16) is communicated with a recycled waste material bin (13) through a metering conveyor (15), the wind power medicine delivery pipe (16, a liquid transfer pipe (18) is connected to the liquid tank (17) through a metering pump (23), and a regeneration device capable of maintaining the reactivity of the desulfurization medium is formed. The lower part of the shell of the spiral sieving machine (10) is provided with an ash discharge hole (11) and a recycling waste bin (13) within 180 degrees, the waste bin (20) is communicated, and the ash discharge hole is a round hole or a conical hole (difficult to block) with large aperture outside. When the device works, according to the requirements of reducing hydraulic resistance and increasing mass transfer surface area, a sphere with the filler granularity of 5-15 mm is adopted, and the circulation multiple is 1.0-10 times per hour. The filler is sent into a spiral stirring conveyor (8), meanwhile, the medicine materials (the molar concentration ratio is 1.2: 1.0) are sent, the recycled waste materials (the quantity is 20-80 percent of the total quantity of the products, and the amount of the recycled materials is reduced when the dust content is large) are sent, and proper water (0.01-0.02L/cubic meter) is added. The liquid and the material are mixed to form a reaction medium with a colloidal active layer surface. The degassing medium moves from top to bottom in the reaction column. Waste gas tangentially flows through the lower packing layer from one side of the lower part of the reaction tower, the humidity of the lower packing layer is low, and the main functions of the waste gas primary reaction, dust interception and material drying are realized. The waste gas enters the upper section packing layer through the smoke box after leaving the lower section, and the upper section packing layer has high humidity; the concentration of the drug is high, the surface area of the agent on the surface of the filler is large, the gaseous sulfide and the desulfurization medium react at a high speed to mainly generate CaSO3 solid, the filler bed on the surface of the wet colloid is kept to adhere and intercept dust, and the gas leaves the outlet at the upper part of the reaction tower and is efficiently purified. The temperature of the flue gas entering the reaction tower is about 150 ℃, the heat value of the flue gas is about 229.98 KJ/cubic meter flue gas [ standard]to ensure that the heat required by the drying material is 59KJ, and obviously enough heat is available for drying the desulfurization filler and the products. The dry materials enter a spiral sieving machine (10), the filler and the surface products are separated by friction and collision, the fine powder falls into each material box, the filler enters a lifter for recycling, the moving speed of a desulfurization medium is adjusted by stepless speed change, the recycled waste materials, new materials and diluents are quantitatively controlled, and the device can be guaranteed to be suitable for high-efficiency and reliable operation under various working conditions.

Claims

1. A packing tower waste gas treatment device, in particular to a continuous regeneration moving bed waste gas treatment tower, which is provided with a reaction tower main body (1) internally provided with packing (12) and is characterized in that a feed inlet (7) at the upper part of a rectangular section reaction tower is communicated with a discharge outlet of a spiral stirring conveyor (8), the feed inlet of the spiral stirring conveyor (8) is communicated with a discharge outlet at the upper part of another vertical spiral elevator (9), a feed inlet at the lower part of the vertical spiral elevator is communicated with a discharge outlet of another spiral screening machine (10), the feed inlet of the spiral screening machine is directly communicated with a discharge outlet (19) at the lower part of the reaction tower main body to form a moving bed, a liquid conveying pipe (18) on a shell (23) of the spiral stirring conveyor is communicated with a solution box through a metering pump (22), a wind power medicine conveying pipe (16) is communicated with a recycling waste material bin (13) through a metering conveyor (15), the waste gas inlet (outlet) ports (2), (3), (5) and (6) and the smoke box (4) form a multi-return-stroke sectional waste gas channel. The moving bed, the regenerating device and the waste gas channel together form the whole body of the continuous regenerating moving bed desulfurizing tower

2. A continuous regenerating moving bed waste gas treating tower according to claim 1, characterized in that the helical mixing conveyor (8) is a vertical screw elevator (9), and the helical screening machine (10) is a stepless speed change transmission

3. A continuous regenerative moving bed waste gas treatment tower apparatus according to claim 1, wherein the pneumatic powder feeding pipe (16) is connected to the feeding fan (21) through a damper (24)

4. The continuous regenerative moving bed waste gas treatment tower apparatus according to claim 1, wherein the spiral screen (10) has a conical ash discharge hole (11) with a circular or large aperture within 180 degrees of thelower portion of the housing and is communicated with the recycling waste bin (13) and the waste bin (20)

5. The device according to claim 1, wherein the exhaust gas inlet (outlet) port (2), (3), (5), (6) has a louver (25)

6. A continuous regenerative moving bed off-gas treatment column apparatus as claimed in claims 1 to 5, which can be used for other off-gas treatments by changing the drug, for example: NO (strong oxide; alkaline substance) is treated, waste gas (caustic soda) containing CL in waste incineration and oil odor (sodium hypochlorite) are treated.