CN101070275A - Formaldehyde absorbing method and system - Google Patents
Formaldehyde absorbing method and system Download PDFInfo
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- CN101070275A CN101070275A CN 200710064918 CN200710064918A CN101070275A CN 101070275 A CN101070275 A CN 101070275A CN 200710064918 CN200710064918 CN 200710064918 CN 200710064918 A CN200710064918 A CN 200710064918A CN 101070275 A CN101070275 A CN 101070275A
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Abstract
This invention relates to formaldehyde absorption approach and system, includes first absorption column, second absorption column and third absorption column that cyclic assimilate formaldehyde gas. The formaldehyde absorption approach includes: first absorption column assimilate external formaldehyde gas to form first absorption concentration formaldehyde liquid; second absorption column assimilate formaldehyde gas that unabsorbed by first absorption column to form second concentration formalin solution that influx to first absorption column; third absorption column assimilate formaldehyde gas that unabsorbed by second absorption column to form third concentration formalin solution that influx to second absorption column; in the process of first, second and third concentration formalin solution forming, transit corresponding circulating pump respectively proceed gas-liquid exchanging in the first absorption column, second absorption column and third absorption column internal recycle corresponding packing layer, till form the state first, second and third concentration formalin solution.
Description
The present invention relates to a kind of absorption process and device that is used for producing formaldehyde, particularly comprise the methanal absorbing system and the formaldehyde absorbing method on a plurality of absorption towers.
Background technology
Formaldehyde is made in the production technique and is absorbed formaldehyde gas with water as solvent, and its concentration is improved constantly, reach finite concentration after, just obtain the industrial formol product.The quality of methanal absorbing system performance directly has influence on the height of the size and the methyl alcohol unit consumption of plant capacity.The factor that influence absorbs has temperature, specific liquid rate and absorption tower structure.The absorption process of formaldehyde is an exothermic process, and the temperature of absorption liquid is raise, and the temperature of absorption liquid is high more, and the solubleness of formaldehyde gas is just more little, and is unfavorable to absorbing.In the process that absorbs, the condensation of water vapour can be emitted a large amount of heat of condensation again, takes away unnecessary heat in the absorption tower so industrial employing adds big cycle volume.Reduce the temperature of absorption liquid by water cooler with water coolant, to reach the purpose that reduces absorption temperature.What specific liquid rate was represented is the long-pending absorption flow that per hour flows through of every square metre of tower section, and size is relevant with internal circulating load.Internal circulating load is little, has then reduced assimilated efficiency owing to spray the uneven ditch leakage phenomenon that is caused; Internal circulating load is big, then can increase systemic resistance, reduces the empty tower gas velocity that allows, and increases energy consumption.Temperature and specific liquid rate are mainly controlled by regulating processing parameter the influence that absorbs.
The absorption tower structure comprises filler material, filler dress method and the influence of liquid distribution device to absorbing to the influence that absorbs.
Traditional absorption system is unreasonable owing to the absorption tower filler is equipped with, the watercooler heat interchanging area is less than normal, the heat exchange weak effect, thereby the assimilated efficiency of formaldehyde is reduced.
Summary of the invention
The purpose of this invention is to provide a kind of formaldehyde absorbing method,, realize that the circulation of PARA FORMALDEHYDE PRILLS(91,95) gas absorbs, thereby improve assimilated efficiency by in three absorption towers, forming the formaldehyde liquid of three kinds of concentration respectively.
Another object of the present invention provides a kind of methanal absorbing system, by three absorption towers of the formaldehyde liquid that can form three kinds of concentration respectively are set, realize that the circulation of PARA FORMALDEHYDE PRILLS(91,95) gas absorbs, thereby improves assimilated efficiency.
According to a first aspect of the invention, provide a kind of formaldehyde absorbing method that absorbs formaldehyde in methanal absorbing system, described system comprises first absorption tower, second absorption tower and the 3rd absorption tower that absorbs formaldehyde gas successively, said method comprising the steps of:
First absorption tower forms the first absorption strength formaldehyde liquid by absorbing the formaldehyde gas from the outside;
Second absorption tower is formed for flowing into the second concentration formaldehyde liquid on first absorption tower by absorbing the unabsorbed formaldehyde gas in first absorption tower;
The 3rd absorption tower is formed for flowing into the 3rd concentration formaldehyde liquid on second absorption tower by absorbing the unabsorbed formaldehyde gas in second absorption tower;
Wherein, in described first, second and the 3rd concentration formalin body formation process, by corresponding circulating pump respectively on described first absorption tower, second absorption tower and the 3rd absorption tower internal recycle formaldehyde solution of in corresponding packing layer, carrying out the gas-liquid mass transfer exchange with formaldehyde gas, until forming described first, second and the 3rd concentration formaldehyde liquid.
The present invention absorbs formaldehyde gas mode by iteration, forms the formaldehyde finished product that flows in the formaldehyde finished product storage tank, i.e. the first concentration formaldehyde liquid.In described iteration absorbs, recycle pump circulates in the formaldehyde solution of carrying out the gas-liquid mass transfer exchange in the packing layer in first absorption tower with formaldehyde gas, recycle pump circulates in the formaldehyde solution of not carrying out the gas-liquid mass transfer exchange in the packing layer in described second absorption tower with the formaldehyde gas that is absorbed by first absorption tower, recycle pump circulates in the formaldehyde solution of not carrying out the gas-liquid mass transfer exchange in the packing layer in described the 3rd absorption tower with the formaldehyde gas that is absorbed by second absorption tower, the 3rd concentration formaldehyde liquid on while the 3rd absorption tower flows into second absorption tower and carries out the exchange of gas-liquid matter as solution and formaldehyde gas, the second concentration formaldehyde liquid on second absorption tower flows into first absorption tower and carries out the gas-liquid exchange as solution and formaldehyde gas, in first absorption tower, form the first concentration formaldehyde liquid thus, thereby fully absorb formaldehyde gas, improved the output efficiency of formaldehyde finished product.
Formaldehyde absorbing method of the present invention also comprises: by the unabsorbed formaldehyde gas in gas-liquid separator separates the 3rd absorption tower, obtain flowing into the recovery liquid that recirculation absorbs that is used in the 3rd absorption tower.This method can further be utilized the unabsorbed formaldehyde gas in the 3rd absorption tower, thereby can improve specific absorption.
Wherein, the formaldehyde solution that described first absorption tower, second absorption tower and the 3rd absorption tower are used to absorb formaldehyde gas is derived from from the soft water of top, the 3rd absorption tower supply and steam condensate (water that the methanol oxidation reaction generates and the steam that must add for control reaction temperature and concentration, the at high temperature steam of Xing Chenging).And, utilize to be derived from the 3rd absorption tower soft formaldehyde solution, in two packing layers of the segmentation setting on described first absorption tower, carry out the gas-liquid mass transfer exchange respectively with formaldehyde gas.
As mentioned above, described the 3rd concentration formaldehyde liquid is the part of the formaldehyde solution on second absorption tower, and the described second concentration formaldehyde liquid is the part of the formaldehyde solution on first absorption tower.
Wherein, the described first concentration formaldehyde liquid is the formaldehyde liquid of concentration 45～50%; The described second concentration formaldehyde liquid is the formaldehyde liquid of concentration 15～20%; Described the 3rd concentration formaldehyde liquid is the formaldehyde liquid of concentration 2～5%.
According to a second aspect of the invention, provide a kind of methanal absorbing system of realizing aforesaid method, being used to circulate absorbs the formaldehyde gas of importing from the outside, comprising:
Via first absorption tower of inlet mouth reception, be used for forming the first absorption strength formaldehyde liquid by absorbing described formaldehyde gas from the outside from the formaldehyde gas of outside;
Via second absorption tower on described first absorption tower of pipe connection, be used for being formed for flowing into the second concentration formaldehyde liquid on first absorption tower by absorbing the unabsorbed formaldehyde gas in first absorption tower;
Be superimposed upon the 3rd absorption tower on described second absorption tower, be used for being formed for flowing into the 3rd concentration formaldehyde liquid on second absorption tower by absorbing the unabsorbed formaldehyde gas in second absorption tower;
Wherein, in described first, second and the 3rd concentration formalin body formation process, by corresponding circulating pump respectively on described first absorption tower, second absorption tower and the 3rd absorption tower internal recycle formaldehyde solution of in corresponding packing layer, carrying out the gas-liquid mass transfer exchange with formaldehyde gas, until forming described first, second and the 3rd concentration formaldehyde liquid.
Methanal absorbing system of the present invention also comprises gas-liquid separator, is used to separate the unabsorbed formaldehyde gas in described the 3rd absorption tower to obtain reclaiming liquid, and this recovery liquid flows into via pipeline and is used for the recirculation absorption in the 3rd absorption tower.
Wherein, the solution of described first absorption tower, second absorption tower and the 3rd absorption tower absorption formaldehyde gas comes from from the soft water and the steam condensate of the supply of top, the 3rd absorption tower.
Wherein, the described first concentration formaldehyde liquid is the formaldehyde liquid of concentration 45～50%; The described second concentration formaldehyde liquid is the formaldehyde liquid of concentration 15～20%; And described the 3rd concentration formaldehyde liquid is the formaldehyde liquid of concentration 2～5%.
Wherein, be provided with the pipe distributor that PARA FORMALDEHYDE PRILLS(91,95) solution distributes, and be provided with the groove type distributor that PARA FORMALDEHYDE PRILLS(91,95) solution distributes again at middle part, described first absorption tower at top, described first absorption tower.The setting of this dual sparger has improved the distribution of liquid effect to collecting, and has increased the gas-to-liquid contact area, thereby has improved assimilated efficiency.
Wherein, described pipe distributor comprises some horizontal distribution pipes, and a plurality of through holes wherein distribute on every horizontal distribution pipe.
Wherein, described pipe distributor also comprises: standpipe; The feed-pipe that connects described standpipe inlet; And the rectangular tank that connects the standpipe mouth; Wherein, described some horizontal distribution pipes are communicated with described rectangular tank respectively.
Wherein, described groove type distributor comprises a plurality of trough type riseies that are arranged on the sparger end plate.
Wherein, by strut member baffle plate is installed at the place, air outlet of described trough type riser.
Wherein, described trough type riser comprises: form four side plates up and down of elongated slot, a plurality of overflow weirs distribute on two long side plates of symmetry at least therein; The a plurality of bar shaped overflow plates that extend from the top down at the inner side-wall of each described long side plate.
Wherein, first absorption tower comprises: be fixed on the first tower inlet pipe that Ta Bishang is used to import formaldehyde gas; Be arranged on packing layer under first tower on the described first tower inlet pipe; Be arranged on the groove type distributor of the liquid that is used on the packing layer under first tower distributing again; Be arranged on packing layer on first tower on the groove type distributor; Be arranged on the distribute pipe distributor of liquid of being used on the packing layer on first tower; Be arranged on the first tower tail gas outlet of cat head; Be arranged on the first tower circulation fluid outlet of tower bottom; Be fixed on the locational first tower circulation fluid inlet of the tower wall that is higher than groove type distributor; And be fixed on the Ta Bi position that is higher than pipe distributor and the first tower self-circulation liquid inlet of communicating pipe sparger.
Wherein, packing layer is filled in Ta Nei and by the grid support that is fixed on the tower wall under described first tower.
Wherein, packing layer is filled in Ta Nei and by the grid support that is fixed on the tower wall on described first tower.
Wherein, groove type distributor is fixed on Ta Bishang by its sparger end plate.
Wherein, the outlet of the first tower circulation fluid on first absorption tower is connected first tower self-circulation liquid inlet and formaldehyde finished product storage tank respectively via the first tower recycle pump, the first tower interchanger and respective line.
Wherein, the outlet of the second tower circulation fluid on second absorption tower is communicated with the first tower circulation fluid inlet on first absorption tower and the second tower self-circulation inlet on second absorption tower respectively via the second tower recycle pump, the second tower interchanger and respective line.
Wherein, the outlet of the first tower tail gas on first absorption tower is communicated with the second tower inlet mouth on second absorption tower via respective line.
Wherein, the outlet of the 3rd tower circulation fluid on the 3rd absorption tower is communicated with the 3rd tower self-circulation liquid inlet via the 3rd tower recycle pump, the 3rd tower interchanger and respective line.
Wherein, the outlet of the 3rd tower tail gas on the 3rd absorption tower connects the inlet of gas-liquid separator via pipeline.
Wherein, the air outlet of gas-liquid separator connects the tail gas sealing groove by pipeline, and the liquid outlet of gas-liquid separator reclaims the liquid inlet via the gas-liquid that pipeline connects the 3rd absorption tower.
Wherein, the 3rd absorption tower is positioned on second absorption tower, and is tightly connected together by vessel flange.
Wherein, fill the second tower packing layer in second absorption tower by the second tower grid support.
Wherein, on the second tower packing layer, be provided with the second tower sparger.
Wherein, fill the 3rd tower packing layer in the 3rd absorption tower by the 3rd tower grid support.
Wherein, on the 3rd tower packing layer, be provided with the 3rd tower sparger.
Wherein, between described the 3rd tower screen and the second tower sparger, be provided with the sealing coat of riser and upflow tube.
Wherein, under described first tower on packing layer, first tower packing layer, the second tower packing layer and the 3rd tower packing layer be the structured packing of stainless steel ripple.
The present invention has following technique effect:
1, adopts the iteration absorption pattern on three absorption towers, can effectively absorb formaldehyde gas, improve formaldehyde finished product output capacity;
2, adopt the regular netted ripple packing segmentation of stainless steel to install, be equipped with tank type liquid distributor again, can obtain bigger specific surface area and voidage, avoid ditch to leak phenomenon effectively, absorption liquid is evenly distributed, increases the gas-to-liquid contact area, thereby improve assimilated efficiency.
The present invention is described in detail below in conjunction with accompanying drawing.
Description of drawings
Fig. 1 is the composition synoptic diagram of absorption system of the present invention;
Fig. 2 is the structure iron on first absorption tower of absorption system of the present invention;
Fig. 3 is the enlarged view of flange connection on first absorption tower of absorption system of the present invention;
Fig. 4 a-4c is the structure iron of the groove type distributor on absorption system of the present invention first absorption tower, and wherein Fig. 4 a is the front view of groove type distributor, and Fig. 4 b is the upward view of groove type distributor shown in Fig. 4 a, and Fig. 4 c is the A-A sectional view of groove type distributor shown in Fig. 4 a;
Fig. 5 a and 5b are the structure iron of the pipe distributor on first absorption tower of absorption system of the present invention, and wherein Fig. 5 a is the front view of pipe distributor, and Fig. 5 b is the vertical view of pipe distributor shown in Fig. 5 a;
Fig. 6 is second absorption tower of absorption system of the present invention and the structure iron on the 3rd absorption tower.
Description of reference numerals: 1, first absorption tower; 2, formaldehyde finished product storage tank; 3, the first tower interchanger; 4, the second tower interchanger; 5, the first tower recycle pump; 6, the second tower recycle pump; 7, the 3rd tower interchanger; 8, the 3rd tower recycle pump; 9, second absorption tower; 10, the 3rd absorption tower; 11, gas-liquid separator; 12, tail gas sealing groove; 13, the first tower inlet pipe; 14, packing layer under first tower; 15, groove type distributor; 16, packing layer on first tower; 17, the first tower pipe distributor; 18, end socket; 19, first tower tail gas outlet; 20, vessel flange; 21, the first tower top grating (filler support); 22, first tower circulation fluid inlet; 23, vessel flange; 24, the first tower lower grid plate (filler support); 25, first tower circulation fluid outlet; 25 ', first tower self-circulation liquid inlet; 26, sparger end plate; 27, riser; 28, baffle plate supports; 29, baffle plate; 30, overflow plate; 31, overflow weir; 32, second tower circulation fluid outlet; 33, the second tower inlet pipe; 34, second packing layer; 35, the second tower sparger; 36, upflow tube; 37, rise inflator; 38, the 3rd tower packing layer; 39, the 3rd tower sparger; 40, column plate; 41, downtake; 42, end socket; 43, the 3rd tower tail gas outlet; 44, vessel flange; 45, soft water inlet; 46, vessel flange; 47, the 3rd tower screen; 48, gas-liquid reclaims the liquid inlet; 49, the 3rd tower circulation fluid outlet; 50, vessel flange; 51, the second tower screen; 53, the 3rd tower self-circulation liquid inlet; 54, second tower self-circulation liquid inlet; 55, central feed-pipe; 56, standpipe; 57, rectangular tank; 58, horizontal distribution pipe.
Embodiment
Below with reference to the Fig. 1 that shows absorption system structure of the present invention formaldehyde absorbing method and methanal absorbing system are described according to the present invention.
Formaldehyde absorbing method of the present invention is realized in the methanal absorbing system that comprises first absorption tower 1, second absorption tower 9 and the 3rd absorption tower 10 that absorb formaldehyde gas successively, be said method comprising the steps of:
First absorption tower 1 forms the first absorption strength formaldehyde liquid by absorbing the formaldehyde gas from the outside;
Second absorption tower 9 is formed for flowing into the second concentration formaldehyde liquid on first absorption tower 1 by absorbing first absorption tower, 1 unabsorbed formaldehyde gas;
The 3rd absorption tower 10 is formed for flowing into the 3rd concentration formaldehyde liquid on second absorption tower 9 by absorbing second absorption tower, 9 unabsorbed formaldehyde gas;
Wherein, in described first, second and the 3rd concentration formalin body formation process, by corresponding circulating pump (promptly, the first tower recycle pump 5, the second tower recycle pump 6, the 3rd tower recycle pump 8) respectively at corresponding packing layer (promptly at described first absorption tower 1, second absorption tower 9 and the 3rd absorption tower 10 internal recycle, packing layer 16, the second tower packing layer 34, the 3rd tower packing layer 38 on packing layer 14, first tower under first tower) in carry out the gas-liquid mass transfer exchange with formaldehyde gas formaldehyde solution, until forming described first, second and the 3rd concentration formaldehyde liquid.
In fact, the present invention absorbs formaldehyde gas mode by iteration to form the formaldehyde finished product (i.e. the first concentration formaldehyde liquid) that flows in the formaldehyde finished product storage tank 2.In described iteration absorbs, recycle pump 5 circulates in the packing layer 14 in first absorption tower 1, carry out the formaldehyde solution of gas-liquid mass transfer exchange in 16 with formaldehyde gas, recycle pump 6 circulates in the formaldehyde solution of not carrying out the gas-liquid mass transfer exchange with the formaldehyde gas that is absorbed by first absorption tower 1 in the packing layer 34 in described second absorption tower 9, recycle pump 7 circulates in the formaldehyde solution of not carrying out the gas-liquid mass transfer exchange with the formaldehyde gas that is absorbed by second absorption tower 9 in the packing layer 38 in described the 3rd absorption tower 10, the 3rd concentration formaldehyde liquid on the 3rd absorption tower 10 flows into second absorption tower 9 simultaneously, carry out the exchange of gas-liquid matter as solution and formaldehyde gas, the second concentration formaldehyde liquid on second absorption tower 9 flows into first absorption tower 1, carry out the gas-liquid exchange as solution and formaldehyde gas, in first absorption tower 1, form the first concentration formaldehyde liquid thus, thereby fully absorb formaldehyde gas, improve the output efficiency of formaldehyde finished product.
In order further to utilize the unabsorbed formaldehyde gas in the 3rd absorption tower, formaldehyde absorbing method of the present invention also comprises: separate the 3rd absorption tower 10 unabsorbed formaldehyde gas by gas-liquid separator 11, obtain flowing into the recovery liquid that recirculation absorbs that is used in the 3rd absorption tower 10, improve the formaldehyde specific absorption thus.
As can be seen from the figure, described first absorption tower 1, second absorption tower 9 and the 3rd absorption tower 10 formaldehyde solution that is used to absorb formaldehyde gas is derived from from the soft water and the steam condensate of the supply of 10 tops, the 3rd absorption tower.And, utilize to be derived from the 3rd absorption tower soft formaldehyde solution, in first absorption tower 1, carry out the gas-liquid mass transfer exchange with formaldehyde gas respectively in the packing layer 16 on packing layer 14 and first tower under first tower of segmentation setting.
As mentioned above, described the 3rd concentration formaldehyde liquid is the part of the formaldehyde solution on second absorption tower 9, and the described second concentration formaldehyde liquid is the part of the formaldehyde solution on first absorption tower 1.
Wherein, the described first concentration formaldehyde liquid is the formaldehyde liquid of concentration 45～50%, and its temperature is about 55 ± 5 degree; The described second concentration formaldehyde liquid is the formaldehyde liquid of concentration 15～20%, and its temperature is about 35 ± 5 degree; Described the 3rd concentration formaldehyde liquid is the formaldehyde liquid of concentration 2～5%, and its temperature is about 30 ± 5 degree.
Referring to Fig. 1, the methanal absorbing system of realization aforesaid method of the present invention comprises:
First absorption tower 1 via inlet mouth 13 receives from the formaldehyde gas of outside is used for forming the first absorption strength formaldehyde liquid by absorbing described formaldehyde gas from the outside;
Via second absorption tower 9 on described first absorption tower 1 of pipe connection, be used for being formed for flowing into the second concentration formaldehyde liquid on first absorption tower 1 by absorbing first absorption tower, 1 unabsorbed formaldehyde gas;
Be superimposed upon the 3rd absorption tower 10 on described second absorption tower 9, be used for being formed for flowing into the 3rd concentration formaldehyde liquid on second absorption tower 9 by absorbing second absorption tower, 9 unabsorbed formaldehyde gas;
Wherein, in described first, second and the 3rd concentration formalin body formation process, by corresponding circulating pump (promptly, the first tower recycle pump 5, the second tower recycle pump 6, the 3rd tower recycle pump 8) respectively at corresponding packing layer (promptly at described first absorption tower 1, second absorption tower 9 and the 3rd absorption tower 10 internal recycle, packing layer 16, the second tower packing layer 34, the 3rd tower packing layer 38 on packing layer 14, first tower under first tower) in carry out the gas-liquid mass transfer exchange with formaldehyde gas formaldehyde solution, until forming described first, second and the 3rd concentration formaldehyde liquid.
Methanal absorbing system of the present invention also comprises gas-liquid separator 11, is used to separate described the 3rd absorption tower 10 unabsorbed formaldehyde gas to obtain reclaiming liquid, and this recovery liquid flows into via pipeline and is used for the recirculation absorption in the 3rd absorption tower 10.
Wherein, be provided with the pipe distributor 17 that PARA FORMALDEHYDE PRILLS(91,95) solution distributes, and be provided with the groove type distributor 15 that PARA FORMALDEHYDE PRILLS(91,95) solution distributes again at 1 middle part, described first absorption tower at 1 top, described first absorption tower.The setting of this dual sparger has improved the distribution of liquid effect to collecting, and has increased the gas-to-liquid contact area, thereby has improved assimilated efficiency.
Referring to Fig. 5 a to Fig. 5 b, pipe distributor 17 of the present invention comprises some horizontal distribution pipes 58, and a plurality of through hole (not shown) wherein distribute on every horizontal distribution pipe 58.
Described pipe distributor 17 also comprises: standpipe 56; The feed-pipe 55 that connects described standpipe 56 inlets; And the rectangular tank 57 that connects standpipe 56 outlets; Wherein, described some horizontal distribution pipes 58 are communicated with described rectangular tank 57 respectively.
Referring to Fig. 4 a to Fig. 4 c, described groove type distributor 15 comprises a plurality of trough type riseies 27 that are arranged on the sparger end plate (or tower tray) 26.Baffle plate 29 is installed by strut member 28 by place, air outlet at described trough type riser 27.
The working process of groove type distributor 15 is: the bottom-up riser 27 that passes of formaldehyde gas that comes from packing layer 14 under first tower, under the effect of baffle plate 29, gas is disperseed, the formaldehyde solution that comes from packing layer 16 on first tower drops on the base plate 26, when reach a certain amount of after, overflow weir 31 from riser sprays into riser 27, falls into overflow plate 31, enters packing layer at last.
Fig. 2 has shown the structure on first absorption tower of the present invention, and first absorption tower 1 of the present invention mainly comprises: be fixed on the first tower inlet pipe 13 that Ta Bishang is used to import formaldehyde gas; Be arranged on packing layer 14 under first tower on the described first tower inlet pipe 13; Be arranged on the groove type distributor 15 of the liquid that is used on the packing layer 14 under first tower distributing again; Be arranged on packing layer 16 on first tower on the groove type distributor 15; Be arranged on the distribute pipe distributor 17 of liquid of being used on the packing layer 16 on first tower; Be arranged on the first tower tail gas outlet 19 of cat head; Be arranged on the first tower circulation fluid outlet 25 of tower bottom; Be fixed on the locational first tower circulation fluid inlet 22 of the tower wall that is higher than groove type distributor 15; And be fixed on the Ta Bi position that is higher than pipe distributor 17 and the first tower self-circulation liquid inlet 25 ' of communicating pipe sparger 17.
Wherein, packing layer 14 is filled in Ta Nei and is supported by the screen 24 that is fixed on the tower wall under described first tower.
Wherein, packing layer 16 is filled in Ta Nei and is supported by the screen 21 that is fixed on the tower wall on described first tower.
Because packing layer 16 on the packing layer 14 and first tower is installed under first tower in segmentation in first absorption tower, therefore can obtain bigger specific surface area and voidage, can avoid ditch to leak phenomenon like this, absorption liquid is evenly distributed, increase the gas-to-liquid contact area, thereby improve assimilated efficiency.
In first absorption tower, groove type distributor 15 is fixed on Ta Bishang by its sparger end plate 26.The first tower circulation fluid outlet 25 on first absorption tower 1 is connected first tower self-circulation liquid inlet 25 ' and formaldehyde finished product storage tank 2 respectively via the first tower recycle pump 5, the first tower interchanger 3 and respective line.
The formaldehyde aspiration that first absorption tower is described below in conjunction with Fig. 2 is received process: formaldehyde gas enters in the tower from the first tower inlet pipe 13, under first tower packing layer 14 with carry out the gas-liquid mass transfer exchange from the formaldehyde solution on tower top, mesh ripple packing in the packing layer 14 supports by the first tower screen 24 and is filled in the tower, unabsorbed formaldehyde gas makes progress along tower, riser 25 through groove type distributor 15 rises to packing layer 16 on first tower, on first tower under packing layer 16 and first tower tower body of packing layer 14 be connected by vessel flange 23, mesh ripple in the packing layer 16 supports by screen 21 and is filled in the tower, the bottom is provided with 15 pairs of liquid of groove type distributor and distributes, at last, formaldehyde gas enters second tower from the first tower tail gas outlet 19 that is located at cat head, the tower body of packing layer 16 and end socket 18 are by vessel flange 20 sealing and fixing together, the formaldehyde solution that comes from the bottom of the tower enters in the tower from pipe distributor 17, be downward through packing layer 16 and carry out the gas-liquid mass transfer exchange with the formaldehyde gas that rises, flow through packing layer 14 after process groove type distributor 15 distributes again and carry out the gas-liquid mass transfer exchange with the formaldehyde gas that rises, fall at the bottom of the tower at last, so continuous circulation, extraction (that is to say as product to increase liquid, liquid level at the bottom of first tower is behind certain altitude, pass through liquid level sensor, automatically open the valve of extraction pipe, still liquid enters finished product storage tank 2 as finished product).
Continuation is referring to Fig. 1, and the outlet 32 of the second tower circulation fluid on second absorption tower 9 is communicated with the second tower self-circulation inlet 54 on first tower circulation fluid inlet, 22 and second absorption tower 9 on first absorption tower 1 respectively via the second tower recycle pump 6, the second tower interchanger 4 and respective line.
The first tower tail gas outlet 19 on first absorption tower 1 is communicated with the second tower inlet mouth 33 on second absorption tower 9 via respective line.
The 3rd tower circulation fluid outlet 49 on the 3rd absorption tower 10 is communicated with the 3rd tower self-circulation liquid inlet 53 via the 3rd tower recycle pump 8, the 3rd tower interchanger 7 and respective line.
The 3rd tower tail gas outlet 43 on the 3rd absorption tower 10 connects the inlet of gas-liquid separator 11 via pipeline.
Wherein, the air outlet of gas-liquid separator 11 connects tail gas sealing groove 12 by pipeline, and the liquid outlet of gas-liquid separator 11 reclaims liquid inlet 48 via the gas-liquid that pipeline connects the 3rd absorption tower 10.
Referring to Fig. 6, in order to reduce floor space and facility investment expense, the 3rd absorption tower 10 is superimposed on second absorption tower 9, and is tightly connected together by vessel flange 50.
As shown in Figure 6, fill the second tower packing layer 34 that supports by the second tower screen 51 in second absorption tower 9, on the second tower packing layer 34, be provided with the second tower sparger 35.
As shown in Figure 6, fill the 3rd tower packing layer 38 that supports by the 3rd tower screen 47 in the 3rd absorption tower 9, on the 3rd tower packing layer 38, be provided with the 3rd tower sparger 39.
Wherein, between described the 3rd tower screen 47 and the second tower sparger 35, be provided with the sealing coat of riser 37 and upflow tube 36.Riser 37 is used for providing its unabsorbed formaldehyde gas to the 3rd absorption tower 10, and upflow tube 36 is used for the 3rd concentration formaldehyde liquid on the 3rd absorption tower 10 is supplied to second absorption tower 9.
In the present invention, under described first tower on packing layer 14, first tower packing layer 16, the second tower packing layer 34 and the 3rd tower packing layer 38 be preferably the structured packing of stainless steel ripple.
The working process of methanal absorbing system of the present invention is described below with reference to Fig. 1, Fig. 2 Fig. 6.
The formaldehyde gas that comes from oxidizer enters first absorption tower 1 by the first tower inlet mouth 13, in first absorption tower 1, formaldehyde gas is upwards by packing layer 14,16 are absorbed the formaldehyde liquid that forms finite concentration (45～50%), the height of packing layer is selected according to different concentration, set up groove type distributor 15 at the tower middle part, collect circulating absorption solution to play again the effect of cloth, thereby reach the purpose of efficient absorption, all formaldehyde liquid exports 25 extraction by the first tower recycle pump 5 from the first tower circulation fluid, and after 3 heat exchange of the first tower interchanger reach certain temperature (about 55 degree), enter the absorption that circulates in the tower from first pipe distributor 17, increase the liquid part (promptly as the product extraction, the first concentration formaldehyde liquid (still liquid) that is positioned at 9 bottoms, first absorption tower flows into formaldehyde finished product storage tank 2 as finished product), unabsorbed formaldehyde gas causes second tower by first tower tail gas outlet 19, unabsorbed formaldehyde gas enters in second tower by the second tower inlet pipe 33 in first absorption tower, in second absorption tower, formaldehyde gas upwards is absorbed the formaldehyde liquid that forms finite concentration (about 20%) by the second tower packing layer 34, the formaldehyde liquid that forms exports 32 extraction from the second tower circulation fluid, by the second tower recycle pump 6 and after 4 heat exchange of the second tower interchanger reach certain temperature (about 35 degree), a part enters 1 tower by first circulation fluid inlet 22, a part enters the circulation of second tower by the second tower pipe distributor 35 and absorbs, unabsorbed formaldehyde gas continues upwards to enter the 3rd tower by riser 37, in the 3rd tower, be absorbed into the formaldehyde liquid of finite concentration (about 5%) by the 3rd tower packing layer 38, a formaldehyde solution part that forms exports 49 extraction from the 3rd tower circulation fluid, by the 3rd tower recycle pump 8 and after 7 heat exchange of the 3rd tower interchanger reach certain temperature (about 30 degree), entering the 3rd tower internal recycle from the 3rd absorption tower pipe distributor 39 absorbs, another part enters second tower by upflow tube 36, the 3rd Tata body and the second Tata body are tightly connected by vessel flange 50, remaining unabsorbed formaldehyde gas continues upwards, by column plate 40, by from soft water (room temperature, concentration is 0) the 42 soft water absorption formation formaldehyde solutions that enter in the tower enter the mouth, the formaldehyde solution that forms enters the 3rd tower packing layer 38 downwards, the nonabsorbable shape gas that do not coagulate in level Four absorption tower enters gas-liquid separator 11 by the 3rd tower tail gas outlet 43, the liquid that obtains after gas-liquid separator separates enters in the tower by liquid inlet 48, and gas separated unnecessary tail gas sealing groove 12 that passes through except that the part circulation enters exhaust treatment system.
A specific examples is described below, if generate the formaldehyde of 45～50% concentration, can adopt following technological process: methyl alcohol is squeezed into vaporizer by pump, and the methyl alcohol add-on is by 535 kilograms of methyl alcohol/ton formaldehyde, methanol gas behind heating evaporation also enters mixing tank, and air is (with 600M
3/ hr.t. formaldehyde) send into superheater by roots blower and reach more than 100 ℃, enter mixing tank through temperature after the preheating; Suitably add steam, the amount of adding can make the ingredients concentration of methyl alcohol reach 65～75%, enters mixing tank; After producing normally, terms and conditions all is in the steady state, exhaust system with air displacement, by exhaust fan cyclic part tail gas (account for air admission amount 70%), enters mixing tank after making it to reach more than 100 ℃ by temperature after the preheater preheating with rare gas element then.Mixed gas purifying treatment after filtration enters the reactor of the electrolytic silver fixed bed of mating formation.Set the ratio of every gas and come the controlled oxidation temperature, generally be controlled between 620～630 ℃, generate formaldehyde gas through oxidative dehydrogenation according to the catalyst activity oxidizing temperature.After first, second, third absorption tower absorbs the first tower concentration 45～50%, temperature 55 degree; The second tower concentration 15～20%, temperature 35 degree; The 3rd tower concentration 2～5%, temperature 30 degree add water by the 3rd absorption tower cat head and control finished product concentration, product is by the first absorption tower extraction product, by statistics, unit consumption is lower than 535 kilograms of methanol/formaldehyde/, less than 550 kilograms of methanol/formaldehyde/of unit consumption (45% concentration) of prior art.
Claims (10)
1, a kind of formaldehyde absorbing method that absorbs formaldehyde in methanal absorbing system is included in the formaldehyde gas that the circulation absorption is supplied from the outside in the methanal absorbing system that is made of a plurality of absorption towers.
2, a kind of formaldehyde absorbing method that absorbs formaldehyde in methanal absorbing system, described methanal absorbing system comprise that circulation absorbs first absorption tower (1), second absorption tower (9) and the 3rd absorption tower (10) of formaldehyde gas, said method comprising the steps of:
First absorption tower (1) forms the first absorption strength formaldehyde liquid by absorbing the formaldehyde gas from the outside;
Second absorption tower (9) is formed for flowing into the second concentration formaldehyde liquid on first absorption tower (1) by absorbing the unabsorbed formaldehyde gas in first absorption tower (1);
The 3rd absorption tower (10) is formed for flowing into the 3rd concentration formaldehyde liquid on second absorption tower (9) by absorbing the unabsorbed formaldehyde gas in second absorption tower (9);
Wherein, in described first, second and the 3rd concentration formalin body formation process, by corresponding circulating pump (5,6,8) respectively on described first absorption tower (1), second absorption tower (9) and the 3rd absorption tower (10) internal recycle be at corresponding packing layer (14,16,34,38) carry out the formaldehyde solution of gas-liquid mass transfer exchange in formaldehyde gas, until forming described first, second and the 3rd concentration formaldehyde liquid.
3, formaldehyde absorbing method according to claim 2, further comprising the steps of: as to separate the unabsorbed formaldehyde gas in the 3rd absorption tower (10) by gas-liquid separator (11), obtain flowing into the recovery liquid that recirculation absorbs that is used in the 3rd absorption tower (10).
4, according to claim 2 or 3 described formaldehyde absorbing methods, wherein, utilization is derived from the 3rd absorption tower (10) soft formaldehyde solution and carries out the gas-liquid mass transfer exchange respectively with formaldehyde gas in two packing layer of the segmentation setting on described first absorption tower (1).
5, according to each described formaldehyde absorbing method of claim 2 to 4, wherein, described the 3rd concentration formaldehyde liquid is the part of the formaldehyde solution on second absorption tower (9), and the described second concentration formaldehyde liquid is the part of the formaldehyde solution on first absorption tower (1).
6, according to each described formaldehyde absorbing method of claim 2 to 5, wherein,
The described first concentration formaldehyde liquid is the formaldehyde liquid of concentration 45～50%;
The described second concentration formaldehyde liquid is the formaldehyde liquid of concentration 15～20%;
Described the 3rd concentration formaldehyde liquid is the formaldehyde liquid of concentration 2～5%.
7, a kind of methanal absorbing system, being used to circulate absorbs the formaldehyde gas of importing from the outside, comprising:
Via first absorption tower (1) of inlet mouth (13) reception, be used for forming the first absorption strength formaldehyde liquid by absorbing described formaldehyde gas from the outside from the formaldehyde gas of outside;
Via second absorption tower (9) on described first absorption tower of pipe connection (1), be used for being formed for flowing into the second concentration formaldehyde liquid on first absorption tower (1) by absorbing the unabsorbed formaldehyde gas in first absorption tower (1);
Be superimposed upon the 3rd absorption tower (10) on described second absorption tower (9), be used for being formed for flowing into the 3rd concentration formaldehyde liquid on second absorption tower (9) by absorbing the unabsorbed formaldehyde gas in second absorption tower (9);
Wherein, in described first, second and the 3rd concentration formalin body formation process, by corresponding circulating pump (5,6,8) respectively on described first absorption tower (1), second absorption tower (9) and the 3rd absorption tower (10) internal recycle be at corresponding packing layer (14,16,34,38) carry out the formaldehyde solution of gas-liquid mass transfer exchange in formaldehyde gas, until forming described first, second and the 3rd concentration formaldehyde liquid.
8, methanal absorbing system according to claim 7, also comprise gas-liquid separator (11), be used to separate the unabsorbed formaldehyde gas in described the 3rd absorption tower (10) to obtain reclaiming liquid, this recovery liquid flows into via pipeline and carries out the recirculation absorption in the 3rd absorption tower (10).
9, according to Claim 8 or 9 described methanal absorbing systems, wherein,
The described first concentration formaldehyde liquid is the formaldehyde liquid of concentration 45～50%;
The described second concentration formaldehyde liquid is the formaldehyde liquid of concentration 15～20%; And
Described the 3rd concentration formaldehyde liquid is the formaldehyde liquid of concentration 2～5%.
10, according to each described methanal absorbing system of claim 7 to 9, wherein, be provided with the pipe distributor (17) that PARA FORMALDEHYDE PRILLS(91,95) solution distributes at top, described first absorption tower (1), and be provided with the groove type distributor (15) that PARA FORMALDEHYDE PRILLS(91,95) solution distributes again at middle part, described first absorption tower (1).
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2007100649182A CN100569725C (en) | 2007-03-29 | 2007-03-29 | Formaldehyde absorbing method and system |
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| CN100569725C CN100569725C (en) | 2009-12-16 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101486633B (en) * | 2009-02-11 | 2012-04-18 | 王承信 | Formaldehyde absorbing tower |
| CN105056706A (en) * | 2015-08-19 | 2015-11-18 | 常州大学 | Methanol waste gas recycling system based on secondary absorption |
| KR20230032275A (en) * | 2021-08-30 | 2023-03-07 | 정철 | F0rmaldehyde absorbing apparatus of formalin manufacturing equipment |
| EP4112155A4 (en) * | 2020-04-02 | 2023-06-07 | Mitsubishi Heavy Industries Engineering, Ltd. | Co2 recovery device and co2 recovery method |
-
2007
- 2007-03-29 CN CNB2007100649182A patent/CN100569725C/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101486633B (en) * | 2009-02-11 | 2012-04-18 | 王承信 | Formaldehyde absorbing tower |
| CN105056706A (en) * | 2015-08-19 | 2015-11-18 | 常州大学 | Methanol waste gas recycling system based on secondary absorption |
| EP4112155A4 (en) * | 2020-04-02 | 2023-06-07 | Mitsubishi Heavy Industries Engineering, Ltd. | Co2 recovery device and co2 recovery method |
| KR20230032275A (en) * | 2021-08-30 | 2023-03-07 | 정철 | F0rmaldehyde absorbing apparatus of formalin manufacturing equipment |
| KR102613321B1 (en) * | 2021-08-30 | 2023-12-12 | 정철 | F0rmaldehyde absorbing apparatus of formalin manufacturing equipment |
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| CN100569725C (en) | 2009-12-16 |
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