CN103112836B

CN103112836B - Method for recycling phosphoric acid in tail gas generated in process of producing activated carbon by phosphoric acid process and utilizing afterheat of tail gas

Info

Publication number: CN103112836B
Application number: CN201310055984.9A
Authority: CN
Inventors: 项瑞芳
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-01-30
Filing date: 2013-01-30
Publication date: 2014-12-17
Anticipated expiration: 2033-01-30
Also published as: CN103112836A

Abstract

The invention relates to a method for recycling phosphoric acid in tail gas generated in a process of producing activated carbon by a phosphoric acid process and utilizing afterheat of the tail gas and belongs to the technical field of activated carbon production. According to the method, internal thermal type rotary kiln equipment is adopted, activated carbon powder is sequentially separated out from the tail gas generated in the process of producing wood powdered activated carbon through phosphoric acid activation by a dust remover under a heat insulation condition, the tail gas passes through a gas-liquid separation demisting phosphoric acid recoverer in a rapid rotation manner from top to bottom for recovering vaporific phosphoric acid, then the tail gas exchanges heat with cold water through a tail gas water vapor condenser, water vapor is condensed, hot water is heated, temperature is reduced below 50 DEG C through heat exchange of the tail gas cooler and cold water, and finally the tail gas is exhausted. According to the method, a good phosphoric acid recycling effect is fulfilled, afterheat is fully utilized, the equipment is simple, and the operation is simple.

Description

A kind of producing active carbon by phosphoric acid method tail gas phosphoric acid reclaims the method with UTILIZATION OF VESIDUAL HEAT IN

One, affiliated technical field

The method of the recovery of producing active carbon by phosphoric acid method tail gas phosphoric acid and UTILIZATION OF VESIDUAL HEAT IN, belongs to chemical method and produces activated carbon technology field, particularly relates to the technology of producing the recovery of gac tail gas phosphoric acid and UTILIZATION OF VESIDUAL HEAT IN.

Two, background technology

With phosphoric acid activation, produce the method for wood powder shaped activated carbon, all use internal heat type rotary kiln device, high-temperature flue gas is thermal source, direct heating material, the tail gas that production process produces, temperature 150-280 ℃, contain phosphatase 11 .5-2.5%, active carbon powder 2-5%, water vapor 60%, flue gas 35%, active carbon finished products per ton, consumption coal 1.8-2.5t, consumption phosphoric acid 0.25-0.28t, serious environment pollution.The treatment process of tail gas, all uses rotating stream tray scrubber spray water cleaning of off-gas, approximately can reclaim in tail gas 25% phosphoric acid, and the phosphoric acid concentration reclaiming is very low, and the waste heat of tail gas does not add utilization.201110458801.9 producing active carbon by phosphoric acid method tail gas and heat recovery technique device,: by cellular electrode structure electric demister collection and treatment phosphoric acid tail gas, by the heat transfer tube arranging more than 2 groups, carry out phosphoric acid tail gas UTILIZATION OF VESIDUAL HEAT IN in flue, by sieve via structure and vacuum condition, carry out Phosphoric Acid Concentration.This method, equipment is complicated, involves great expense, and easily fouling is stopped up, and the Phosphoric Acid Concentration reclaiming can not be arrived to the concentration of the required phosphoric acid of producing active carbon by phosphoric acid method complex acid.

Three, summary of the invention

In order to overcome the existing internal heat type rotary kiln device of using, phosphoric acid activation is produced wood powder shaped activated carbon method, vent gas treatment technology imperfection, phosphoric acid reclaims not exclusively, and heat energy does not utilize, and causes Activated Carbon Production coal consumption high, phosphoric acid consumption is large, and the defects such as serious environment pollution, propose a kind of efficient, the method for phosphoric acid and using waste heat from tail gas utilization in easy recovery tail gas.

1, technical scheme:

Internal heat type rotary kiln device, phosphoric acid method is produced the tail gas that wood powder shaped activated carbon produces, in adiabatic condition, the first step, pass through continuously dust removal process, isolate active carbon powder, remove solid impurity, the mat woven of fine bamboo strips two steps, reclaim the phosphoric acid acid mist in tail gas, with fast rotational form, pass through from top to bottom gas-liquid cyclonic separation demist formula phosphoric acid withdrawer, phosphoric acid droplet is subject to centrifugal settling effect and is thrown toward to reclaim on wall and converges and form phosphoric acid liquid film, along wall, flow downward, until bottom enters acid accumulator storage by liquid outlet, tail gas is rotated down to flow and arrives turning center, withdrawer bottom, enter vapor pipe rising and discharge phosphoric acid withdrawer, the mat woven of fine bamboo strips three steps, tail gas water vapor condensation and cold water heat exchange, tail gas enters condenser from up to down by condenser and the reverse partition heat exchange of the bottom-up cold water passing through, tail gas is progressively cooled to below dew point, discharge cooling sensible heat, latent heat of liquefaction, pass to water coolant, be heated to more than 80 ℃, the 4th step, tail gas cooling with cold water heat exchange, tail gas enters water cooler, from up to down by water cooler and the reverse partition heat exchange of the bottom-up cold water passing through, tail gas is further cooled to below 50 ℃, water coolant is heated to more than 40 ℃, send into again tail gas steam condenser, the mat woven of fine bamboo strips five steps, exhaust emissions, tail gas is taken out tying-in gas chimney by centrifugal high pressure fan and is discharged.

Tails dedusting described in technical scheme is processed, with settling methods, keep off a kind of dry method dust in process of cleaning, cyclone dust removal method again, under adiabatic condition, with less wind speed, isolate active carbon powder, remove the solid impurity in tail gas, in order to avoid later vent gas treatment process, equipment inner wall fouling, pipe pass blocking plug, isolated active carbon powder, the phosphoric acid that contains 60-70% is reclaimed together with activation charcoal.

Gas-liquid separation demist formula phosphoric acid withdrawer described in technical scheme, for a plurality of diameters are 50-300mm, the small-sized gas-liquid cyclonic separation mist eliminator that inside has volution guide blade structures forms phosphoric acid withdrawer, tail gas is due to the guide functions of guiding flow rotation blade, speed with 6-20m/s in withdrawer is rotated down mobile, phosphoric acid acid mist in tail gas collides each other cohesion and grows up, centrifugal settling is in wall, converge and form sorrel decline, make the phosphoric acid acid mist in tail gas obtain complete Separation and Recovery, organic efficiency reaches more than 95%.

Tail gas steam condenser described in technical scheme, is vertical type, and length-to-diameter ratio is at more than 10 water-cooled shell and tube or shell and tube cooler, and cold water is walked shell side, and tail gas is walked tube side.

Exhaust gas cooler described in technical scheme, is vertical type, and length-to-diameter ratio is at more than 10 water-cooled shell and tube or shell and tube cooler, and cold water is walked shell side, and tail gas is walked tube side.

Cold water described in technical scheme is from cold water source, and the water cooler of flowing through is heated to more than 40 ℃, then the condenser of flowing through is heated to more than 80 ℃, finally flows into boiler.

2, useful benefit

Producing active carbon by phosphoric acid method tail gas phosphoric acid of the present invention reclaims the method with UTILIZATION OF VESIDUAL HEAT IN, with existing active production technology comparison, there is equipment simple, reduced investment, producing active carbon by phosphoric acid method tail gas phosphoric acid organic efficiency high (reaching 95%), UTILIZATION OF VESIDUAL HEAT IN are filled part (reaching 80%), save steam boiler, reduce coal consumption (reaching 18%), reduce phosphoric acid consumption (reaching 90%), reduce environmental pollution, the advantage such as increase economic efficiency.

Four, accompanying drawing explanation

1, producing active carbon by phosphoric acid method tail gas phosphoric acid reclaims and residual-heat utilization method schema

Note in accompanying drawing:

1, tornado dust collector; 2, gac storage tank; 3, gas-liquid cyclonic separation demist formula phosphoric acid withdrawer; 4, phosphoric acid storage tank; 5, tail gas steam condenser; 6, condensate storage tank; 7, exhaust gas cooler; 8, induced draft fan.

Five, embodiment

Below in conjunction with accompanying drawing and Reference numeral, method steps of the present invention is described in detail.

The recovery of producing active carbon by phosphoric acid method tail gas phosphoric acid and residual-heat utilization method flow process are as shown in Figure 1.Use internal heat type rotary kiln device, phosphoric acid activation is produced wood powder shaped activated carbon method, production process produces temperature 150-280 ℃, phosphoric acid 1.5-2.5%, active carbon powder 2-5%, water vapor 60%, the tail gas of flue gas 35%, under adiabatic condition, first pass through dust removal process, isolate active carbon powder, remove purification activated carbon solid impurity, in order to avoid later vent gas treatment process, equipment inner wall fouling, pipe pass blocking plug, the active carbon powder reclaiming, the phosphoric acid that contains 60-70%, reclaimed together with activation charcoal, tails dedusting treatment process, with settling methods, keep off again process of cleaning, a kind of dry method dust in cyclone dust removal method, prefered method is cyclone dust removal method, its equipment is as the tornado dust collector in Fig. 1 (1).Secondly, carrying out phosphoric acid acid mist in tail gas reclaims, tail gas is passed through to gas-liquid cyclonic separation demist formula phosphoric acid withdrawer from top to bottom with fast rotational form, phosphoric acid droplet is subject to centrifugal settling effect and is thrown toward to reclaim on wall and converges and form phosphoric acid liquid film, along wall, flow downward, until bottom enters phosphoric acid storage tank (4) by liquid outlet, reclaim to obtain acid mist shape phosphoric acid in tail gas; Tail gas is rotated down to flow and arrives turning center, withdrawer bottom, enter vapor pipe rising and discharge phosphoric acid withdrawer, phosphoric acid withdrawer is as the gas-liquid vortex-flow and defrosting formula phosphoric acid withdrawer (3) in Fig. 1, for a plurality of diameters are 50-300mm, inside is provided with the falling liquid film gas-liquid cyclonic separation demist formula phosphoric acid withdrawer of the blade of spiral helicine guiding flow rotation, and the speed of rotation that tail gas passes through is 6-20m/s.The mat woven of fine bamboo strips three steps, tail gas water vapor condensation and cold water heat exchange, tail gas enters condenser from up to down by condenser and the reverse partition heat exchange of the bottom-up cold water passing through, tail gas is progressively cooled to below dew point, tail gas cooling discharges sensible heat, water vapor condensation liquefaction, discharge latent heat of liquefaction, with the reverse partition heat exchange of cold water from water cooler, tail gas is cooled to below 90 ℃, water coolant is heated to more than 80 ℃, flow into boiler's (not drawing on figure), water vapor condensation water flows into condensate storage tank (6), tail gas condenser is as the tail gas steam condenser (5) in Fig. 1, for vertical type water-cooled shell and tube or shell and tube cooler, cold water is walked shell side, tail gas is walked tube side, the hot water reclaiming and water of condensation are for the moisturizing of Activated Carbon Production complex acid, activation charcoal phosphoric acid reclaims water and activated carbon rinsing water, the 4th step, tail gas cooling with cold water heat exchange, tail gas enters water cooler, from up to down by water cooler and the reverse partition heat exchange of the bottom-up cold water passing through, tail gas is further cooled to below 50 ℃, discharge sensible heat, water coolant is heated to more than 40 ℃, send into again tail gas steam condenser, exhaust gas cooler is as the exhaust gas cooler in Fig. 1 (7), for vertical type water-cooled shell and tube or shell and tube cooler, cold water is walked shell side, tail gas is walked tube side, cold water fork-like farm tool used in ancient China is from cold water source, the water cooler of flowing through, the condenser of flowing through again, finally flow into boiler, the mat woven of fine bamboo strips five steps, exhaust emissions, tail gas is taken out the discharge of tying-in gas chimney by centrifugal high pressure fan (8).

Claims

1. producing active carbon by phosphoric acid method tail gas phosphoric acid reclaims the method with UTILIZATION OF VESIDUAL HEAT IN, it is characterized by: tail gas, in adiabatic condition, the first step, pass through continuously dust removal process, isolate active carbon powder, remove solid impurity, the mat woven of fine bamboo strips two steps, reclaim the phosphoric acid acid mist in tail gas, tail gas passes through gas-liquid cyclonic separation demist formula phosphoric acid withdrawer from top to bottom with fast rotational form, on phosphoric acid droplet centrifugal settling wall, pool phosphoric acid liquid film, along wall, drop to bottom and enter acid accumulator storage through liquid outlet, tail gas arrives turning center, withdrawer bottom, enter vapor pipe rising and discharge phosphoric acid withdrawer, the mat woven of fine bamboo strips three steps, tail gas water vapor condensation and cold water heat exchange, tail gas enters condenser from up to down by condenser and the reverse partition heat exchange of the bottom-up cold water passing through, tail gas is progressively cooled to below dew point, discharge cooling sensible heat, latent heat of liquefaction, pass to water coolant, be heated to more than 80 ℃, the 4th step, tail gas cooling with cold water heat exchange, tail gas enters water cooler, from up to down by water cooler and the reverse partition heat exchange of the bottom-up cold water passing through, tail gas is further cooled to below 50 ℃, water coolant is heated to more than 40 ℃, send into again tail gas steam condenser, the mat woven of fine bamboo strips five steps, exhaust emissions, tail gas is taken out tying-in gas chimney by centrifugal high pressure fan and is discharged.

2. producing active carbon by phosphoric acid method tail gas phosphoric acid according to claim 1 reclaims the method with UTILIZATION OF VESIDUAL HEAT IN, it is characterized by: dust removal process method is settling methods, keeps off a kind of dry gas cleaning method in process of cleaning, cyclone dust removal method again.

3. producing active carbon by phosphoric acid method tail gas phosphoric acid according to claim 1 reclaims the method with UTILIZATION OF VESIDUAL HEAT IN, it is characterized by: the phosphoric acid acid mist in tail gas reclaims, with a plurality of diameter 50-300mm, the small-sized gas-liquid cyclonic separation mist eliminator that inside has spiral blade guide frame forms phosphoric acid withdrawer, and tail gas passes through mist eliminator with the speed of rotation of 6-20m/s.

4. producing active carbon by phosphoric acid method tail gas phosphoric acid according to claim 1 reclaims the method with UTILIZATION OF VESIDUAL HEAT IN, it is characterized by: tail gas water vapor condensation and cold water heat exchange, by vertical type, length-to-diameter ratio is at more than 10 shell and tubes or shell and tube cooler, tail gas is walked tube side, and cold water is walked shell side.

5. producing active carbon by phosphoric acid method tail gas phosphoric acid according to claim 1 reclaims the method with UTILIZATION OF VESIDUAL HEAT IN, it is characterized by: tail gas cooling with cold water heat exchange, by vertical type, length-to-diameter ratio is at more than 10 shell and tubes or shell and tube cooler, tail gas is walked tube side, and cold water is walked shell side.