CN103695063A - Method for concentrating low-concentration methane gas - Google Patents
Method for concentrating low-concentration methane gas Download PDFInfo
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- CN103695063A CN103695063A CN201310723718.9A CN201310723718A CN103695063A CN 103695063 A CN103695063 A CN 103695063A CN 201310723718 A CN201310723718 A CN 201310723718A CN 103695063 A CN103695063 A CN 103695063A
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Abstract
The invention discloses a method for concentrating low-concentration methane gas. According to the method, the low-concentration methane gas with the CH4 concentration not more than 30%.V and the pressure not more than 0.05 MPa.G is concentrated through a pressure swing adsorption process. The method comprises the following steps: adsorbing by N (N is not less than 3) adsorption towers, wherein each adsorption tower is filled with an adsorbent; cyclically performing N adsorption stages in an adsorption cycle, wherein N-1 serial adsorption is performed by the adsorption tower; after the N adsorption towers are serially connected and subjected to pressure equalization in each adsorption stage, washing and replacing the adsorption tower after the N-1 adsorption, vacuuming and desorbing; in addition, serially connecting the N-1 adsorption towers, reversely increasing the pressure to be the adsorption pressure, and adsorbing; repeating in the way to finish the adsorption cycle. Compared with the prior art, the method has the benefits that the CH4 yield is greatly increased, the CH4 concentration increment value is high, and the investment and running costs are low.
Description
Technical field
The present invention relates to a kind of method of extracting low-concentration coal mine gas.
Background technology
China Shi Yi big coal country, coal mine gas resource is very abundant, and in China 2000m, coal seam tolerance reaches 35 tcms, suitable with land conventional gas amount.Most of CH in current China's coal-mine coal mine gas
4concentration is all lower, national < < safety regulations in coal mine > > regulation CH
4concentration bans use of lower than 30% coal mine gas, can only emptying process, and has caused the significant wastage of resource.If can fully recycle this part resource, to alleviating the discharge of China's energy shortage, minimizing greenhouse gases, all play significant role, of far-reaching significance.
In order to reclaim as much as possible coal mine gas resource, a lot of schools, R&D institution have carried out development research, have proposed multiple coal mine gas concentrate CH
4method, mainly contain indirect Deep Cooling Method, catalytic oxidation, solution absorption method, pressure-variable adsorption partition method.
Indirect Deep Cooling Method: be to utilize cold medium to CH
4cryogenic liquefying, and non-condensable gas N
2, O
2emptying, a large amount of non-condensable gas degree of depth is cooling, causes energy consumption high, has limited it in the dense use of low concentration gas air lift.Equipment manufacturing cost is high in addition, start-stop car is slow;
Catalytic oxidation: utilize CH
4and O
2under the effect of catalyzer, react, by the O in coal mine gas
2consume, make coal mine gas energy safe operation in subsequent disposal, due to CH in catalyzed reaction
4also to be consumed CH
4concentration is lower, i.e. O
2content is higher, consumes CH
4higher, CH
4yield is lower, therefore more should not adopt in low concentration gas gas is concentrated.In catalyzed reaction, also can produce CO in addition
2etc. new impurity, increased the treatment step of removing impurities;
Solution absorption method: adopt absorption liquid, absorbing and removing O
2after be applied again, this technology is at present also immature, cannot be applied in industrial production;
Pressure-variable adsorption partition method: technology is the most ripe, and simple with its flow process, level of automation is high, less investment, working cost are low becomes unique technological method that drops into industry operation, at CH
4-N
2in fractionation by adsorption, because the separation factor of sorbent material is lower, CH in adsorption process
4the concentration gradient forming in tower is smaller, CH in keeping tower top absorption tail gas
4when concentration is lower, the agent of tower internal adsorption reaches saturated just the lacking of absorption, CH in stripping gas
4content is also just lower, and at CH
4-N
2in fractionation by adsorption, we wish CH in absorption tail gas
4more low better, to improve CH
4yield, wishes again CH in stripping gas
4concentration is more high better, but in an adsorption tower, the two is difficult to get both, therefore there are many people to propose the pressure swing adsorption technique of multiple tandem type, as CN1140418A, CN1334135A, CN1334136A, CN1248482, CN1347747A, the patents such as CN1248482A are reported, these processing methodes are all to adopt two cover PSA device series connection absorption, be that the tail gas of first set absorption is as the unstripped gas of the second cover absorption, in order to make easy adsorbent component Enrichment in stripping gas, just make easy adsorbent component concentration in absorption tail gas suitably raise, and be less than unstripped gas, this strand of gas is because easily adsorbent component content is low after the second cover absorption, in absorption tail gas, easily adsorbent component will be lower than only using a set of PSA, aforesaid two desired values have so just been improved, owing to being that two cover PSA devices move simultaneously, its investment cost must be high, working cost is corresponding improve also.
Also there is people to propose one-step series-connected pressure swing adsorption technique for above-mentioned shortcoming, as CN1394665A, this technique is at least comprised of 3 adsorption towers, as A, B, C tri-towers, if A tower adsorbs just for the second time, unstripped gas enters at the bottom of by A tower, control A column overhead give vent to anger in easy adsorbent component to high density slightly, this gas enters the B tower adsorbing in for the first time at the bottom of tower, from B tower top easy adsorbent component concentration step-down out, reach requirement, meanwhile C tower all falls, find time, all rise, the processes such as final rise, make C pressure tower reach adsorptive pressure, treat A, after B series connection has been adsorbed, can start next round B, C tower series connection absorption, A tower all falls, find time, all rise, final rise waited.In this process, as general pressure-swing adsorption process, clean tower after all falling, finding time, be adsorbed again relative saturation for the second time absorption after tower in all calm the anger pollute, easily adsorbent component concentration surpasses in adsorption tower for the first time, and in tower, also fails to set up and the corresponding concentration gradient of absorption.When entering next round series connection absorption, easily adsorbent component tower high and that do not set up again respective concentration gradient but enters the back segment of series connection absorption, obviously will have influence on the reduction of the easy adsorbent component of series connection absorption tail gas.
Summary of the invention
The present invention proposes a kind of method of extracting low-concentration coal mine gas, solved deficiency of the prior art, use the method to carry out concentrate coal mine gas gained CH
4yield significantly improves, and CH
4the increment of concentration is high, and less investment, working cost are low.
Technical scheme of the present invention is achieved in that
A method for extracting low-concentration coal mine gas, it adopts pressure swing adsorption technique to carry out CH the coal mine mash gas of low pressure, lower concentration
4concentrate, the method employing N(N>=3) individual adsorption tower adsorbs, in described each adsorption tower, sorbent material is all housed, in an adsorption cycle, loop altogether N absorption phase, in each absorption phase after N adsorption tower series average-voltage, the adsorption tower that has carried out N-1 absorption is rinsed, replaced, and then N-1 the reverse adsorptive pressure that boosts to of adsorption tower series connection adsorb in addition; So then circulation completes an adsorption cycle.
It specifically comprises the steps:
(1) raw material coal mine gas enters successively in N-1 the adsorption tower adsorbing of connecting and carries out fractionation by adsorption, the adsorption tower that now raw material coal mine gas enters is at first to carry out the N-1 time absorption, the adsorption tower finally entering is to adsorb for the first time, the tower that has carried out on last stage adsorbing and completing flushing for N-1 time, replace is vacuumized to desorb simultaneously;
(2) after the fractionation by adsorption in completing steps (1), N-1 adsorption tower of this series connection absorption vacuumizes the adsorption tower that carries out desorb and connects with completing, carry out N tower series average-voltage, the interior gas of adsorption tower that now completes absorption for the first time has forward flowed into the adsorption tower that vacuumizes desorb, complete the interior gas of adsorption tower of absorption for the second time, forward flowed in the adsorption tower of absorption for the first time, the rest may be inferred, the interior gas of adsorption tower that completes the N-1 time absorption, has forward flowed in the adsorption tower of the N-2 time absorption;
(3) after all pressures in completing steps (2), the adsorption tower that completes the N-1 time absorption disconnects with the adsorption tower that completes the N-2 time absorption, and rinse, replace completing the tower of the N-1 time absorption with stripping gas, simultaneously, the tower that completes for the first time absorption with complete the adsorption tower that vacuumizes desorb and connect, and with absorption tail gas to series connection the reverse adsorptive pressure that boosts to of N-1 tower, now complete first absorption phase;
(4) in completing steps (3) displacement and boost after, absorption enters second absorption phase, and the adsorption tower that completes flushings, replace is vacuumized to desorb, simultaneously to completing the absorption of connecting of N-1 tower of reverse series boosting; Now the tower of absorption for the first time of first absorption phase enters absorption for the second time, vacuumize the adsorption tower that carries out desorb and enter absorption for the first time, the tower of the N-2 time absorption of N-1 absorption phase enters the N-1 time absorption, the tower of the N-1 time absorption enters and vacuumizes desorb, process through identical with first absorption phase, completes second absorption phase, so circulation, then complete N absorption phase, complete an adsorption cycle.
Further, when adsorbing, adsorptive pressure is 30-50KPa.
Further, described activated carbon of sorbent class sorbent material, silica type sorbent material and molecular sieve sorbent material.
Further, described adsorption tower is 3～4.
In the present invention, the sorbent material adopting is three kinds: gac class sorbent material, silica type sorbent material and molecular sieve sorbent material, but depending on concrete unstripped gas situation, also can only adopt two kinds of sorbent materials, three tower process processes of the present invention are to adopt cascade towers absorption, in an adsorption cycle each adsorption tower will with the absorption of respectively once connecting of former and later two adsorption towers, after each absorption, two towers of this series connection again with complete the tower that vacuumizes regeneration and connect, carry out three tower cascade connected all pressures, the interior gas of tower that now completes absorption for the first time forward flows into vacuum column, complete the interior gas of tower of absorption for the second time, forward flowed in the tower of absorption for the first time, after completing all and pressing, the tower that completes absorption for the second time disconnects with the tower that completes absorption for the first time, and rinse completing the tower of absorption for the second time with stripping gas, displacement, the tower that simultaneously completes absorption is for the first time connected with the regenerator column of finding time, and with the reverse adsorptive pressure that boosts to of absorption tail gas.After completing displacement and boosting, to completing the tower of displacement, vacuumize desorb, simultaneously to completing the absorption of connecting of two towers of reverse series boosting, now the tower of absorption for the first time of first stage enters for the second time and adsorbs, vacuumizes that regenerator column enters for the first time absorption, the tower of absorption enters and vacuumizes regeneration for the second time, absorption enters subordinate phase, and the process through identical with the first stage, completes subordinate phase, then complete the phase III, complete an adsorption cycle.So circulation, forms a continuous adsorption separation process.
When carrying out cascade towers absorption, allow more CH
4through last tower, make the more sorbent material of last tower reach adsorption equilibrium, make CH in tower
4content increases.And through the gas of last tower because not penetrating completely, CH
4content is much smaller than material concentration, through after the fractionation by adsorption of a tower, just can obtain CH
4the absorption tail gas that relative concentration is lower, makes CH
4yield improves.
Three tower cascade connected all pressures after absorption, are that three towers join end to end, pressure equalizing CH
4in full accord when formed concentration gradient and absorption, be conducive to fractionation by adsorption subsequently, and enter the gas at the bottom of the regenerator column tower of finding time, be CH in front two towers
4relative concentration is minimum, is conducive to control tail gas CH
4concentration.In the reverse series boosting of tail gas subsequently, use CH
4rear two towers that the absorption tail gas that content is minimum is all pressed three towers carry out reverse boosting, by the part CH in the regenerator column tower of finding time after all pressing
4at the bottom of pressing to tower, then press to the tower being attached thereto, make CH in the regenerator column of finding time after all pressing
4become lower,, and CH
4concentration gradient in tower is consistent with adsorption process, is equilateral triangle, the CH of the regenerator column tower top of finding time
4concentration is minimum, and this is conducive in adsorption process CH in absorption tail gas
4the reduction of concentration, thus CH further improved
4yield.
CH wish absorption tail gas in low concentration gas gas separating and concentrating in
4concentration is more low better, to improve to greatest extent CH
4yield, the CH in stripping gas that wishes again to find time simultaneously
4concentration is high as far as possible, to improve CH
4enrichment multiple, be conducive to follow-up further concentrate and use.But in sepn process, this two is conflict values, i.e. CH in tail gas
4concentration reduces, CH in stripping gas
4concentration also will decrease, and adopts preceding method of the present invention, can be at tail gas CH
4concentration slows down CH in the stripping gas of finding time while reducing
4the reduction of concentration, for further improving CH in the stripping gas of finding time
4concentration, the tower that arranges again useful stripping gas to complete second adsorption in technological process purges, and makes in tower in dead space containing O
2, N
2many gas mixtures are displaced, simultaneously also can be by the O adsorbing in sorbent material
2, N
2cemented out partially, thereby made CH in stripping gas
4concentration is further improved.In processing arrangement, the exhaust gas after purging is turned back to raw material storage tank, this is no doubt to reduce CH on the one hand
4loss, keeps yield, can improve on the other hand into CH in tower material mixed gas
4concentration, unstripped gas CH
4concentration improves, and when other conditions are identical, can further improve CH in stripping gas
4concentration.If the tolerance of returning can be mentioned mixture strength more than 18%, gas will depart from explosive range, favourable to safety.
When raw gas pressure can overcome resistance when three tower cascade connected, can select four tower adsorption process, adopt three tower cascade connected absorption, a tower to rinse and vacuumize desorb, four tower series average-voltages, the reverse technological process of boosting of three tower cascade connected absorption tail gas.In this process, each adsorption tower in each adsorption cycle will complete with adjacent adsorption tower three absorption of connecting, and after having adsorbed, three towers of this series connection are connected with completing the tower that vacuumizes desorb again, carry out four tower series average-voltages at every turn.After completing all and pressing, the tower that completes absorption for the third time disconnects with the tower that completes absorption for the second time, and rinse completing the tower of absorption for the third time with stripping gas, displacement, the tower that simultaneously completes for the first time absorption with vacuumize regenerator column and connect, and with the reverse adsorptive pressure that boosts to of absorption tail gas, after completing displacement and boosting, to completing the tower of displacement, vacuumize desorb, three towers that simultaneously complete reverse series boosting absorption of connecting, this process enters subordinate phase, through the process identical with the first stage, complete subordinate phase, then complete the phase III, fourth stage, complete an adsorption cycle, so circulation, form a continuous adsorption separation process.The operation of this technological process, more favourable control absorption tail gas CH
4cH in the reduction of concentration and raising stripping gas
4enrichment multiple.
Compared with prior art, the invention has the beneficial effects as follows:
(1) use the method to carry out the coal mine gas of extracting low-concentration, pressure can be less than to CH in the mash gas extraction gas of 50KPa
4from 5%-30% concentrate to 30%-60%, yield is greater than 90%;
(2) use the method to carry out the coal mine gas of extracting low-concentration, less investment, working cost are low.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, below the accompanying drawing of required use during embodiment is described is briefly described, apparently, accompanying drawing in the following describes is only one of them embodiment of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is the process flow sheet of the embodiment of the present invention one;
Fig. 2 is the process flow sheet of the embodiment of the present invention two.
Embodiment
Below the technical scheme in the present invention is clearly and completely described, obviously, described embodiment is only several embodiment wherein of the present invention, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.
As depicted in figs. 1 and 2:
Embodiment 1:
In the present embodiment, adopt three adsorption towers.Adsorptive pressure is 30KPa, unstripped gas CH
4concentration is 7.7%.
The device of the 1.1 extracting low-concentration coal mine gas that adopt:
It comprises that three adsorption towers (are respectively the first adsorption tower 171, the second adsorption tower 172, the 3rd adsorption tower 173), in described each adsorption tower, sorbent material is all housed, the sorbent material adopting is in the present embodiment gac class sorbent material, silica type sorbent material and molecular sieve sorbent material, described three adsorption towers are joined end to end and are connect by pipeline, the adsorption tower of head end and tail end also joins end to end by pipeline, and on connected pipeline, be provided with respectively sequencing valve between tower and (be respectively sequencing valve 41 between the first tower, sequencing valve 43 between sequencing valve 42, the three towers between the second tower); This device also comprises vacuum pump 8, air inlet surge tank 9, stripping gas surge tank 10 and absorption tail gas surge tank 111,
Described air inlet surge tank 9 is connected in the bottom of each adsorption tower and is provided with respectively air inlet sequencing valve (being respectively the first air inlet sequencing valve 11, the second air inlet sequencing valve 12, the three air inlet sequencing valves 13) on the pipeline that connects each adsorption tower by pipeline;
Described stripping gas surge tank 10 is connected in the bottom of each adsorption tower and is provided with respectively stripping gas sequencing valve on the pipeline that connects each adsorption tower by pipeline and (is respectively the first stripping gas sequencing valve 21, the second stripping gas sequencing valve 22, the three stripping gas sequencing valves 23); And described stripping gas surge tank 10 is connected in the bottom of each adsorption tower by pipeline, and on the pipeline that connects each adsorption tower, be provided with respectively displacement gas sequencing valve and (be respectively the first displacement gas sequencing valve 31, the second displacement gas sequencing valve 32, the 3rd displacement gas sequencing valve 33), from tower displacement gas out, through sequencing valve, (be respectively the first displacement gas outlet sequencing valve 61 respectively, the second displacement gas outlet sequencing valve 62, the 3rd displacement gas outlet sequencing valve 63), enter into air inlet surge tank 9, mix with unstripped gas;
Described absorption tail gas surge tank 111 is connected in the top of each adsorption tower and is provided with respectively absorption tail gas sequencing valve on the pipeline that connects each adsorption tower by twin flue and (is respectively the first tail gas sequencing valve 71, the second tail gas sequencing valve 72, the 3rd tail gas sequencing valve 73) and the tail gas sequencing valve that boosts (be respectively the first tail gas sequencing valve 51 that boosts, the second tail gas sequencing valve 52, the three tail gas sequencing valve 53 that boosts that boosts);
One end of described vacuum pump 8 is connected in stripping gas surge tank 10 by pipeline, its the other end is connected to each adsorption tower by pipeline, and on the pipeline of each adsorption tower, be provided with respectively stripping gas sequencing valve and (be respectively the first stripping gas sequencing valve 21 being connected in, the second stripping gas sequencing valve 22, the three stripping gas sequencing valves 23).
On described air inlet surge tank 9, be connected with intake ducting 121.
On described stripping gas surge tank 10, be connected with stripping gas escape pipe 131, and be connected with stripping gas variable valve 141 on stripping gas escape pipe 131.
On described absorption tail gas surge tank 111, be connected with absorption tail gas escape pipe 151, and be connected with absorption tail gas variable valve 161 on absorption tail gas escape pipe 151.
The method that the device of the above-mentioned extracting low-concentration coal mine gas of 1.2 application carries out extracting low-concentration coal mine gas is as follows:
It adopts three adsorption towers to adsorb, in an adsorption cycle, loop altogether three absorption phase, in each absorption phase after three adsorption tower series average-voltages, the adsorption tower that has carried out twice absorption is rinsed, replaced, then vacuumize desorb, then the reverse adsorptive pressure that boosts to of two other adsorption tower series connection adsorbs; After three absorption phase have circulated, complete an adsorption cycle, it specifically comprises the steps:
I, first absorption phase: the first adsorption tower 171 and the second adsorption tower 172 series connection absorption; The 3rd adsorption tower 173 vacuumizes desorb;
(1) cascade towers absorption and a tower vacuumize desorb: raw material coal mine gas enters air inlet surge tank 9, returning to gas with the displacement entering mixes, through the first air inlet sequencing valve 11, enter the first adsorption tower 171, after fractionation by adsorption, through between the first tower, sequencing valve 41 enters the second adsorption tower 172 again, then through the second tail gas sequencing valve 72, enters absorption tail gas surge tank 111.In this stage, the first adsorption tower 171 is to have carried out absorption for the second time, and the second adsorption tower 172 has carried out absorption for the first time.The 3rd stripping gas sequencing valve 23 is opened simultaneously, by 8 pairs of the 3rd adsorption towers 173 of vacuum pump, is vacuumized and is carried out desorb, and stripping gas enters stripping gas surge tank 10, then is controlled and sent by stripping gas variable valve 141;
(2) three tower cascade connected all pressures: when the first adsorption tower 171, after the second adsorption tower 172 series connection have been adsorbed, enter the first adsorption tower 171, the second adsorption tower 172, the 3rd adsorption tower 173, three tower cascade connected pressure equalizing, now between the second tower, sequencing valve 42 is opened, the gas of the second adsorption tower 172 sequencing valve 42 through between the second tower flows to the 3rd adsorption tower 173, gas sequencing valve 41 through between the first tower of the first adsorption tower 171 flows to the second adsorption tower 172 and completes all pressures simultaneously, after three pressure tower balances, all presses and finishes;
(3) one towers rinse and reverse the boosting of two towers series connection: when the first adsorption tower 171, the second adsorption tower 172, the 3rd adsorption tower 173 is three tower cascade connected all pressed after, between the first tower, sequencing valve 41 cuts out, the first adsorption tower 171 and the second adsorption tower 172, the 3rd adsorption tower 173 are cut off, enter the first adsorption tower 171 flushings, displacement, the second adsorption tower 172, the reverse process of boosting of the 3rd adsorption tower 173 series connection, now stripping gas is by stripping gas surge tank 10, through the first stripping gas sequencing valve 31, enter the first adsorption tower 171, to adsorbent bed, rinse, replace.This gas flows out the first adsorption towers 171 and returns to air inlet surge tank 9 through give vent to anger sequencing valve 61 of the first displacement gas, after mixing with unstripped gas as the air inlet of adsorbing.Absorption tail gas enters the 3rd adsorption tower 173 by absorption tail gas surge tank 111 through the 3rd absorption tail gas sequencing valve 53 simultaneously, then by sequencing valve 42 between the second tower, enter the second adsorption tower 172, complete the second adsorption tower 172, the 3rd adsorption tower 173 series connection tail gas boost, first absorption phase finishes, then circulation successively;
II, second absorption phase: the second adsorption tower 172 and the 3rd adsorption tower 173 series connection absorption; The first adsorption tower 171 vacuumizes desorb;
III, the 3rd absorption phase: the 3rd adsorption tower 173 and the first adsorption tower 171 series connection absorption; The second adsorption tower 172 vacuumizes desorb;
Complete after above-mentioned three absorption phase, complete an adsorption cycle, complete whole adsorption process.
Embodiment 2:
In the present embodiment, adopt four adsorption towers to adsorb.Adsorptive pressure is 50KPa, unstripped gas CH
4concentration is 6.5%.
The device of the 2.1 extracting low-concentration coal mine gas that adopt:
It comprises that four adsorption towers (are respectively the first adsorption tower 171, the second adsorption tower 172, the 3rd adsorption tower 173, the 4th adsorption tower 174), in described each adsorption tower, sorbent material is all housed, the sorbent material adopting is in the present embodiment gac class sorbent material, silica type sorbent material and molecular sieve sorbent material, described four adsorption towers are joined end to end and are connect by pipeline, the adsorption tower of head end and tail end also joins end to end by pipeline, and on connected pipeline, be provided with respectively sequencing valve between tower and (be respectively sequencing valve 41 between the first tower, between the second tower, sequencing valve 42, sequencing valve 43 between the 3rd tower, sequencing valve 44 between the 4th tower), this device also comprises vacuum pump 8, air inlet surge tank 9, stripping gas surge tank 10 and absorption tail gas surge tank 111,
Described air inlet surge tank 9 is connected in the bottom of each adsorption tower and is provided with respectively air inlet sequencing valve on the pipeline that connects each adsorption tower by pipeline and (is respectively the first air inlet sequencing valve 11, the second air inlet sequencing valve 12, the 3rd air inlet sequencing valve 13, the four air inlet sequencing valves 14), described stripping gas surge tank 10 is connected in the bottom of each adsorption tower and is provided with respectively stripping gas sequencing valve on the pipeline that connects each adsorption tower by pipeline and (is respectively the first stripping gas sequencing valve 21, the second stripping gas sequencing valve 22, the 3rd stripping gas sequencing valve 23, the 4th stripping gas sequencing valve 24), and described stripping gas surge tank 10 is connected in the bottom of each adsorption tower and is provided with respectively displacement gas sequencing valve on the pipeline that connects each adsorption tower by pipeline and (is respectively the first displacement gas sequencing valve 31, the second displacement gas sequencing valve 32, the 3rd displacement gas sequencing valve 33, the 4th displacement gas sequencing valve 34), from tower displacement gas out, through sequencing valve, (be respectively the first displacement gas outlet sequencing valve 61 respectively, the second displacement gas outlet sequencing valve 62, the 3rd displacement gas outlet sequencing valve 63, the first displacement gas outlet sequencing valve 64), enter into air inlet surge tank 9, mix with unstripped gas,
Described absorption tail gas surge tank 111 is connected in the top of each adsorption tower and is provided with respectively absorption tail gas sequencing valve on the pipeline that connects each adsorption tower by twin flue and (is respectively the first tail gas sequencing valve 71, the second tail gas sequencing valve 72, the 3rd tail gas sequencing valve 73, the 4th tail gas sequencing valve 74) and the tail gas sequencing valve that boosts (be respectively the first tail gas sequencing valve 51 that boosts, the second tail gas sequencing valve 52 that boosts, the 3rd tail gas sequencing valve 53, the four tail gas sequencing valve 54 that boosts that boosts);
One end of described vacuum pump 8 is connected in stripping gas surge tank 10 by pipeline, its the other end is connected to each adsorption tower by pipeline, and on the pipeline of each adsorption tower, be provided with respectively stripping gas sequencing valve and (be respectively the first stripping gas sequencing valve 21 being connected in, the second stripping gas sequencing valve 22, the 3rd stripping gas sequencing valve 23, the four stripping gas sequencing valves 24).
On described air inlet surge tank 9, be connected with intake ducting 121.
On described stripping gas surge tank 10, be connected with stripping gas escape pipe 131, and be connected with stripping gas variable valve 141 on stripping gas escape pipe 131.
On described absorption tail gas surge tank 111, be connected with absorption tail gas escape pipe 151, and be connected with absorption tail gas variable valve 161 on absorption tail gas escape pipe 151.
The method that the device of the above-mentioned extracting low-concentration coal mine gas of 2.2 application carries out extracting low-concentration coal mine gas is as follows:
It adopts four adsorption towers to adsorb, in an adsorption cycle, loop altogether four absorption phase, in each absorption phase after four adsorption tower series average-voltages, the adsorption tower that has carried out three absorption is rinsed, replaced, then vacuumize desorb, then the reverse adsorptive pressure that boosts to of other three adsorption towers series connection adsorbs; After four absorption phase have circulated, complete an adsorption cycle, it specifically comprises the steps:
I, first absorption phase: the first adsorption tower 171, the second adsorption tower 172 and the 3rd adsorption tower 173 series connection absorption; The 4th adsorption tower 174 vacuumizes desorb:
(1) three tower cascade connected absorption and a tower vacuumize desorb: raw material coal mine gas enters air inlet surge tank 9, returning to gas with the displacement entering mixes, through the first air inlet sequencing valve 11, enter the first adsorption tower 171, after fractionation by adsorption, through between the first tower, sequencing valve 41 enters the second adsorption tower 172 again, after fractionation by adsorption, through between the second tower, sequencing valve 42 enters the 3rd adsorption tower 173 again, then through the 3rd tail gas sequencing valve 72, enters absorption tail gas surge tank 111.In this stage, the first adsorption tower 171 is to have carried out absorption for the third time, and the second adsorption tower 172 has carried out absorption for the second time, and the 3rd adsorption tower 173 has carried out absorption for the first time.The 4th stripping gas sequencing valve 24 is opened simultaneously, by 8 pairs of the 4th adsorption towers 174 of vacuum pump, is vacuumized and is carried out desorb, and stripping gas enters stripping gas surge tank 10, then is controlled and sent by stripping gas variable valve 141;
(2) four tower series average-voltages: when the first adsorption tower 171, after the second adsorption tower 172 and Dang tri-adsorption tower 173 series connection have been adsorbed, enter the first adsorption tower 171, the second adsorption tower 172, the 3rd adsorption tower 173 3 towers, with the 4th adsorption tower 174 series average-voltage processes, now between the 3rd tower, sequencing valve 43 is opened, the gas of the 3rd adsorption tower 173 sequencing valve 43 through between the 3rd tower flows to the 4th adsorption tower 174, the gas of the second adsorption tower 172 sequencing valve 42 through between the second tower flows to the 3rd adsorption tower 173, gas sequencing valve 41 through between the first tower of the first adsorption tower 171 flows to the second adsorption tower 172 and completes all pressures simultaneously, after three pressure tower balances, all press and finish,
(3) one towers rinse and three tower cascade connected reverse boosting: when the first adsorption tower 171, the second adsorption tower 172, the 3rd adsorption tower 173, after the 4th adsorption tower 174 4 tower series average-voltages complete, between the first tower, sequencing valve 41 cuts out, make the first adsorption tower 171 and the second adsorption tower 172, the 3rd adsorption tower 173, the 4th adsorption tower 174 cuts off, entering the first adsorption tower 171 rinses, displacement, the second adsorption tower 172, the 3rd adsorption tower 173, the reverse process of boosting of the 4th adsorption tower 174 series connection, now stripping gas is by stripping gas surge tank 10, through the first stripping gas sequencing valve 31, enter the first adsorption tower 171, to adsorbent bed, rinse, displacement.This gas flows out the first adsorption towers 171 and returns to air inlet surge tank 9 through give vent to anger sequencing valve 61 of the first displacement gas, after mixing with unstripped gas as the air inlet of adsorbing.Absorption tail gas enters the 4th adsorption tower 174 by absorption tail gas surge tank 111 through adsorbing the 4th tail gas sequencing valve 54 simultaneously, then by sequencing valve 43 between the 3rd tower, enter the 3rd adsorption tower 173, through between the second tower, sequencing valve 42 enters the second adsorption tower 172 again, completing the second adsorption tower 172, the 3rd adsorption tower 173, the 4th adsorption tower 174 series connection tail gas boosts, first absorption phase finishes, then circulation successively;
II, second absorption phase: the second adsorption tower 172, the 3rd adsorption tower 173 and the 4th adsorption tower 174 series connection absorption; The first adsorption tower 171 vacuumizes desorb;
III, the 3rd absorption phase: the 3rd adsorption tower 173, the 4th adsorption tower 174 and the first adsorption tower 171 series connection absorption; The second adsorption tower 172 vacuumizes desorb;
IV, the 4th absorption phase: the 4th adsorption tower 174, the first adsorption tower 171 and the second adsorption tower 172 series connection absorption; The 3rd adsorption tower 173 vacuumizes desorb.
Complete after above-mentioned four absorption phase, complete an adsorption cycle, complete whole adsorption process.
Embodiment 3:
In the present embodiment, adopt three adsorption towers to adsorb.Adsorptive pressure is 40KPa, unstripped gas CH
4concentration is 12.0%, and concrete adsorption process is with embodiment 1.
Embodiment 4:
In the present embodiment, adopt three adsorption towers to adsorb.Adsorptive pressure is 45KPa, unstripped gas CH
4concentration is 22.0%, and concrete adsorption process is with embodiment 1.
Embodiment 5:
In the present embodiment, adopt three adsorption towers to adsorb.Adsorptive pressure is 35KPa, unstripped gas CH
4concentration is 28.0%, and concrete adsorption process is with embodiment 1.
In embodiment 1-5, adsorption conditions and result are as following table:
Wherein, CH
4increment
*(%)=stripping gas CH
4(%)-unstripped gas CH
4(%)
As can be seen from the above table, in embodiment 1-5, CH
4the equal > 90% of yield, CH
4the increment of concentration
*equal > 25%.
The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (5)
1. a method for extracting low-concentration coal mine gas, is characterized in that: it adopts pressure swing adsorption technique to carry out CH the coal mine mash gas of low pressure, lower concentration
4concentrate, the method employing N(N>=3) individual adsorption tower adsorbs, in described each adsorption tower, sorbent material is all housed, in an adsorption cycle, loop altogether N absorption phase, in each absorption phase, there is the absorption of connecting of N-1 adsorption tower, another tower vacuumizes desorb, thereafter carry out the series average-voltage of N adsorption tower, after all having pressed, the adsorption tower that has carried out N-1 absorption is rinsed, displacement, then N-1 the reverse adsorptive pressure that boosts to of adsorption tower series connection adsorb in addition, to completing flushing, the adsorption tower of displacement vacuumizes desorb, enter second absorption phase, so circulation is N time, complete an adsorption cycle.
2. the method for a kind of extracting low-concentration coal mine gas according to claim 1, is characterized in that: it specifically comprises the steps:
(1) raw material coal mine gas enters successively in N-1 the adsorption tower adsorbing of connecting and carries out fractionation by adsorption, the adsorption tower that now raw material coal mine gas enters is at first to carry out the N-1 time absorption, the adsorption tower finally entering is to adsorb for the first time, the tower that has carried out before adsorbing and completing flushing for N-1 time, replace is vacuumized to desorb simultaneously;
(2) after the fractionation by adsorption in completing steps (1), N-1 adsorption tower of this series connection absorption vacuumizes the adsorption tower that carries out desorb and connects with completing, carry out N tower series average-voltage, the interior gas of adsorption tower that now completes absorption for the first time has forward flowed into the adsorption tower that vacuumizes desorb, complete the interior gas of adsorption tower of absorption for the second time, forward flowed in the adsorption tower of primary sorption, the rest may be inferred, the interior gas of adsorption tower that completes N-1 absorption, has forward flowed in the adsorption tower of N-2 absorption;
(3) after all pressures in completing steps (2), the adsorption tower that completes N-1 absorption disconnects with the adsorption tower that completes N-2 absorption, and rinse, replace completing the tower of N-1 absorption with stripping gas, simultaneously, the tower that completes for the first time absorption vacuumizes the adsorption tower that carries out desorb and connects with completing, and with absorption tail gas to series connection the reverse adsorptive pressure that boosts to of N-1 tower, now complete first absorption phase;
(4) in completing steps (3) displacement and boost after, absorption enters second absorption phase, and the adsorption tower that completes flushings, replace is vacuumized to desorb, simultaneously to completing the absorption of connecting of N-1 tower of reverse series boosting; Now the tower of absorption for the first time of first absorption phase enters absorption for the second time, vacuumize the adsorption tower that carries out desorb and enter absorption for the first time, the tower of the N-2 time absorption enters the N-1 time absorption, the tower that before carries out the N-1 time absorption enters and vacuumizes desorb, through the process identical with first absorption phase, complete second absorption phase, so circulation, then completes N absorption phase and completes an adsorption cycle.
3. the method for a kind of extracting low-concentration coal mine gas according to claim 1 and 2, is characterized in that: when adsorbing, adsorptive pressure is 30-50KPa.
4. the method for a kind of extracting low-concentration coal mine gas according to claim 1 and 2, is characterized in that: described sorbent material is gac class sorbent material, silica type sorbent material and molecular sieve sorbent material.
5. the method for a kind of extracting low-concentration coal mine gas according to claim 1 and 2, is characterized in that: described adsorption tower is 3～4.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105233623A (en) * | 2015-11-19 | 2016-01-13 | 四川省达科特能源科技股份有限公司 | Novel technology of concentrating coal-mine low-concentration gas |
| CN105727687A (en) * | 2015-06-01 | 2016-07-06 | 代元军 | Desorption gas recycling apparatus and desorption gas recycling method for pressure swing adsorption apparatus |
| CN111603886A (en) * | 2020-05-29 | 2020-09-01 | 北京科技大学 | NOx recovery method and device in three-tower switching mode |
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| EP0055669A1 (en) * | 1980-12-29 | 1982-07-07 | Calgon Corporation | Repressurization for pressure swing adsorption system |
| EP0146082A2 (en) * | 1983-12-15 | 1985-06-26 | Linde Aktiengesellschaft | Process for the separation of water vapour and carbon dioxide from a gas stream by adsorption |
| CN101732946A (en) * | 2009-12-31 | 2010-06-16 | 四川省达科特能源科技有限公司 | Production method for pressure-swing adsorption concentration of methane in gas |
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| EP0055669A1 (en) * | 1980-12-29 | 1982-07-07 | Calgon Corporation | Repressurization for pressure swing adsorption system |
| EP0146082A2 (en) * | 1983-12-15 | 1985-06-26 | Linde Aktiengesellschaft | Process for the separation of water vapour and carbon dioxide from a gas stream by adsorption |
| CN101732946A (en) * | 2009-12-31 | 2010-06-16 | 四川省达科特能源科技有限公司 | Production method for pressure-swing adsorption concentration of methane in gas |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105727687A (en) * | 2015-06-01 | 2016-07-06 | 代元军 | Desorption gas recycling apparatus and desorption gas recycling method for pressure swing adsorption apparatus |
| CN105233623A (en) * | 2015-11-19 | 2016-01-13 | 四川省达科特能源科技股份有限公司 | Novel technology of concentrating coal-mine low-concentration gas |
| CN111603886A (en) * | 2020-05-29 | 2020-09-01 | 北京科技大学 | NOx recovery method and device in three-tower switching mode |
| CN111603886B (en) * | 2020-05-29 | 2021-10-22 | 北京科技大学 | NOx recovery method and device in three-tower switching mode |
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| CN103695063B (en) | 2015-04-22 |
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