CN103112836A

CN103112836A - 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: CN103112836A
Application number: CN2013100559849A
Authority: CN
Inventors: 项瑞芳
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-01-30
Filing date: 2013-01-30
Publication date: 2013-05-22
Anticipated expiration: 2033-01-30
Also published as: CN103112836B

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

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

Two, background technology

Produce the method for wood powder shaped activated carbon with phosphoric acid activation, all use the internal heat type rotary kiln device, high-temperature flue gas is thermal source, the 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 is all used rotating stream tray scrubber spray water cleaning of off-gas, approximately can reclaim in tail gas 25% phosphoric acid, and the phosphoric acid concentration that reclaims 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, carry out the phosphoric acid tail gas UTILIZATION OF VESIDUAL HEAT IN by the heat transfer tube that arranges more than 2 groups in flue, carry out Phosphoric Acid Concentration by sieve via structure and vacuum condition.This method, equipment is complicated, involves great expense, and easily fouling is stopped up, and the Phosphoric Acid Concentration that reclaims can not be arrived 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 the Activated Carbon Production coal consumption high, phosphoric acid consumption is large, and the defectives 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:

the internal heat type rotary kiln device, phosphoric acid method is produced the tail gas that the 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, two steps of the mat woven of fine bamboo strips, reclaim the phosphoric acid acid mist in tail gas, pass through from top to bottom gas-liquid cyclonic separation demist formula phosphoric acid withdrawer with the fast rotational form, the phosphoric acid droplet is subjected to the centrifugal settling effect and is thrown toward to reclaim to converge on wall and forms the phosphoric acid liquid film, flow downward along wall, until the bottom enters acid accumulator storage by liquid outlet, tail gas is rotated down to flow and arrives turning center, withdrawer bottom, enter the vapor pipe rising and discharge the phosphoric acid withdrawer, three steps of the mat woven of fine bamboo strips, 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 that passes through, tail gas progressively is cooled to below dew point, discharge the cooling sensible heat, latent heat of liquefaction, pass to water coolant, be heated to more than 80 ℃, the 4th step, cooling and the cool hydrothermal exchange of tail gas, tail gas enters water cooler, from up to down by water cooler and the reverse partition heat exchange of the bottom-up cold water that passes through, tail gas is further cooled to below 50 ℃, water coolant is heated to more than 40 ℃, send into again the tail gas steam condenser, five steps of the mat woven of fine bamboo strips, exhaust emissions, tail gas is taken out the discharging of tying-in gas chimney by centrifugal high pressure fan.

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, isolate active carbon powder with less wind speed, 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 contains the phosphoric acid of 60-70%, is reclaimed together with the 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 the volution guide blade structures forms the phosphoric acid withdrawer, tail gas is due to the guide functions of directing air flow rotating paddle, 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 water-cooled shell and tube or shell and tube cooler more than 10, 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 water-cooled shell and tube or shell and tube cooler more than 10, 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 ℃, flows at last the 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, compare with existing active production technology, has 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%), environmental contamination reduction, the advantage such as increase economic efficiency.

Four, description of drawings

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

Note in accompanying drawing:

1, tornado dust collector; 2, the gac storage tank; 3, gas-liquid cyclonic separation demist formula phosphoric acid withdrawer; 4, phosphoric acid storage tank; 5, the 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 the internal heat type rotary kiln device, phosphoric acid activation is produced wood powder shaped activated carbon method, production process produces 150-280 ℃ of temperature, phosphoric acid 1.5-2.5%, active carbon powder 2-5%, water vapor 60%, the tail gas of flue gas 35%, under adiabatic condition, at first pass through dust removal process, isolate active carbon powder, remove the purification activated carbon solid impurity, in order to avoid later vent gas treatment process, the equipment inner wall fouling, pipe pass blocking plug, the active carbon powder that reclaims, the phosphoric acid that contains 60-70%, reclaimed together with the activation charcoal, the tails dedusting treatment process, use settling methods, keep off again process of cleaning, a kind of dry method dust in the cyclone dust removal method, prefered method is the cyclone dust removal method, tornado dust collector in its equipment such as Fig. 1 (1).Secondly, carry out phosphoric acid acid mist recovery in tail gas, tail gas is passed through gas-liquid cyclonic separation demist formula phosphoric acid withdrawer from top to bottom with the fast rotational form, the phosphoric acid droplet is subjected to the centrifugal settling effect and is thrown toward to reclaim to converge on wall and forms the phosphoric acid liquid film, flow downward along wall, until the bottom enters phosphoric acid storage tank (4) by liquid outlet, reclaim to get acid mist shape phosphoric acid in tail gas; Tail gas is rotated down to flow and arrives turning center, withdrawer bottom, enter the vapor pipe rising and discharge the phosphoric acid withdrawer, gas-liquid vortex-flow and defrosting formula phosphoric acid withdrawer (3) in phosphoric acid withdrawer such as 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 directing air flow rotation, and the speed of rotation that tail gas passes through is 6-20m/s.three steps of the mat woven of fine bamboo strips, 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 that passes through, tail gas progressively is cooled to below dew point, the tail gas cooling discharges sensible heat, water vapor condensation liquefaction, discharge latent heat of liquefaction, with from the reverse partition heat exchange of the cold water of 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 steam condenser (5) in tail gas condenser such as Fig. 1, be 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 that reclaims and water of condensation are used for the moisturizing of Activated Carbon Production complex acid, activation charcoal phosphoric acid reclaims water and activated carbon rinsing water, the 4th step, cooling and the cool hydrothermal exchange of tail gas, tail gas enters water cooler, from up to down by water cooler and the reverse partition heat exchange of the bottom-up cold water that passes through, tail gas further is cooled to below 50 ℃, discharge sensible heat, water coolant is heated to more than 40 ℃, send into again the tail gas steam condenser, exhaust gas cooler in exhaust gas cooler such as Fig. 1 (7), be 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 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, flow at last the boiler, five steps of the mat woven of fine bamboo strips, exhaust emissions, tail gas is taken out the discharging 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, two steps of the mat woven of fine bamboo strips, 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 the fast rotational form, pool the phosphoric acid liquid film on phosphoric acid droplet centrifugal settling wall, drop to the bottom along wall and enter acid accumulator storage through liquid outlet, tail gas arrives turning center, withdrawer bottom, enter the vapor pipe rising and discharge the phosphoric acid withdrawer, three steps of the mat woven of fine bamboo strips, 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 that passes through, tail gas progressively is cooled to below dew point, discharge the cooling sensible heat, latent heat of liquefaction, pass to water coolant, be heated to more than 80 ℃, the 4th step, cooling and the cool hydrothermal exchange of tail gas, tail gas enters water cooler, from up to down by water cooler and the reverse partition heat exchange of the bottom-up cold water that passes through, tail gas is further cooled to below 50 ℃, water coolant is heated to more than 40 ℃, send into again the tail gas steam condenser, five steps of the mat woven of fine bamboo strips, exhaust emissions, tail gas is taken out the discharging of tying-in gas chimney by centrifugal high pressure fan.

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: the 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 70-250mm, the small-sized gas-liquid cyclonic separation mist eliminator that inside has the spiral blade guide frame forms the phosphoric acid withdrawer, and tail gas passes through mist eliminator with the speed of rotation of 8-16Km/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, with vertical type, length-to-diameter ratio is at the shell and tube more than 10 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 the cold water heat exchange, with vertical type, length-to-diameter ratio is at the shell and tube more than 10 or shell and tube cooler, tail gas is walked tube side, and cold water is walked shell side.