CN1039584C - Direct method for prodn. of formaldehyde using natural gas as raw material - Google Patents
Direct method for prodn. of formaldehyde using natural gas as raw material Download PDFInfo
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- CN1039584C CN1039584C CN94111961A CN94111961A CN1039584C CN 1039584 C CN1039584 C CN 1039584C CN 94111961 A CN94111961 A CN 94111961A CN 94111961 A CN94111961 A CN 94111961A CN 1039584 C CN1039584 C CN 1039584C
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Abstract
The present invention relates to a direct method for producing formaldehyde by using natural gas, which is a novel production process designed according to the principle of a membrane reactor on the basis of NO as a homogeneous phase and boron as a heterogeneous catalyst. The method is characterized in that (1) steam is mixed into a reactor before reaction mixed gas enters; (2) the middle and the lower part of a reaction zone are connected with running water by a coil pipe to quench. The steam forms a water membrane on the surface of the quenching pipe and formaldehyde as an unstable intermediate product is absorbed by the water membrane to separate from the reaction zone so that a chemical equilibrium in a gas phase is destructed and a reaction continuously moves toward the direction of formaldehyde generation, and therefore, the present invention obtains 3 to 4 times of formaldehyde single-process yield higher than that of an old method (increasing to 10 to 12% from about 3%.
Description
The invention belongs to the preparation method who directly makes formaldehyde by Sweet natural gas.
The main component of Sweet natural gas is a methane, is that the research of formaldehyde is long-standing with conversion of natural gas.Present method is to be synthetic gas with methane conversion earlier, produces methyl alcohol by synthetic gas again, at last by methanol production formaldehyde.The production method that is prepared formaldehyde by the methane oxidation step had been arranged again afterwards, and the key of this method is a catalyzer, and reported in literature is used for this catalyst for reaction and has reached kind more than 100.N as K.J.Zhen research
2O and V
2O
5-SiO
2, the N of Spencer report
2O and MoO
3-SiO
2Deng, these activity of such catalysts are all very low, and the formaldehyde productive rate of some thousandths of is only arranged.Catalyzer is used to such an extent that be preferably the homogeneous phase heterogeneous catalyst and develop simultaneously, and for example Romania and USSR (Union of Soviet Socialist Republics) are homogeneous catalyst with nitrogen protoxide all, the porcelain ring that boric acid is handled or quartzy for heterogeneous catalyst acquisition about 3% the formaldehyde productive rate and build up the production of large-scale factory.Carry out years of researches through a large amount of investigators, methane oxidation mechanism has been carried out deep discussion, the conclusion that draws is that maximum output has only about 3% according to the kinetic balance estimation.China adopts the method for the Soviet Union, has set up 9～10 middle-size and small-size factories that produce 500 tons of formaldehyde per year 60～seventies, the result of operation, and the one-pass yield of formaldehyde has only about 2%, closes down in succession or stopping production because cost is too high.
The objective of the invention is to improve existing method of producing formaldehyde,, lower the production cost of formaldehyde to improve the per pass conversion that methane conversion is a formaldehyde significantly by the Sweet natural gas oxidation step.
The objective of the invention is to realize by following proposal.
On the method basis of original formaldehyde productive rate 3%, adding water vapour and unstripped gas enter reaction zone simultaneously in unstripped gas (air and methane), and the add-on of water vapour is 0.5～3ml (liquid)/min.Simultaneously in reaction zone, the bottom adds quench tube, the type of cooling is the logical indirect quenching of tap water of serpentine tube.Other reaction conditionss of present method are: air: methane=(1～4): 1, feed gas flow rates is 50～300ml/min, temperature of reaction is that 600～750 ℃ of homogeneous catalysts are nitrogen protoxide, the nitrogen protoxide consumption is 1～9%, heterogeneous catalyst is used the surface of Sodium Tetraborate treatment reactor, with air and methane is unstripped gas, and through one step of oxidation system formaldehyde, its reaction formula is:
The present invention adds water vapour in reaction mixture gas effect is: the 1. adding of a large amount of water vapour; the reactant gases volume is expanded rapidly; linear gas velocity surge in the reaction zone; instantaneous shortening of the residence time; to reach the purpose that protection formaldehyde is not further decomposed as intermediate; freeze reaction and make it deeply not carry out, thereby tire out so that formaldehyde obtains collection.2. the formaldehyde of Sheng Chenging can directly be absorbed and shift out reaction zone by water, thereby destroys the chemical kinetics balance in the gas phase, makes reaction continue to carry out to the direction that generates formaldehyde, reaches the purpose of further raising formaldehyde productive rate.3. according to reported in literature, water vapour has protection formaldehyde to make it the effect that is difficult for being decomposed in this reaction.
To in the reaction zone, the rear portion effect of carrying out quenching is: 1. in time the quenching reaction mixture gas is blocked subsequent reactions and reversed reaction, the formaldehyde that protection generates.2. steam forms moisture film at the quench tube outside surface, can directly absorb formaldehyde, avoids formaldehyde further to be decomposed.3. form in the moisture film process at the quench tube outside surface at the anterior water vapour that adds of reaction zone, the cohesion of vapour molecule has been strengthened the absorption of formaldehyde in moisture film.The result who absorbs has destroyed chemical kinetics balance in the gas phase, helps the generation that formaldehyde keeps.4. in the gas phase a large amount of steam cohesions the gas mixture volume is diminished suddenly and manage in the strong temperature difference, make gas phase formation eddy current, further strengthened formaldehyde and absorbed by water.
Embodiment 1: the influence of temperature of reaction PARA FORMALDEHYDE PRILLS(91,95) productive rate
Reaction conditions: air/CH
4=4: 1, feed gas flow rates: 150ml/min,
Amount of water: 1ml (liquid)/min, NO%=7
| Scheme | Temperature of reaction ℃ | Transformation efficiency % | Formaldehyde selectivity % | Formaldehyde productive rate % |
| 1 2 3 4 | 600 650 700 750 | 20.6 35.5 48.6 51.3 | 23.4 21.3 17.5 15.5 | 4.65 7.57 8.51 7.98 |
Embodiment 2: the influence of amount of water PARA FORMALDEHYDE PRILLS(91,95) productive rate
Reaction conditions: temperature of reaction: 700 ℃, air/CH
4=4: 1, NO%=7
Feed gas flow rates: 150ml/min
| Scheme | Amount of water ml (liquid)/min | Transformation efficiency % | Formaldehyde selectivity % | Formaldehyde productive rate % |
| 1 2 3 4 5 6 | 0.5 1.0 1.5 2.0 2.5 3.0 | 50.0 48.6 43.5 42.5 39.5 38.5 | 14.0 17.5 26.8 27.0 30.1 30.2 | 7.05 8.51 11.5 11.5 12.0 11.7 |
Embodiment 3: the influence of unstripped gas concentration PARA FORMALDEHYDE PRILLS(91,95) productive rate
Reaction conditions: temperature: 700 ℃, feed gas flow rates: 150ml/min
Amount of water: 2ml (liquid)/min, NO%=7
| Scheme | Air: methane | Transformation efficiency % | Selectivity % | Formaldehyde productive rate % |
| 1 2 3 4 | 4∶1 3∶1 2∶1 1∶1 | 42.5 37.4 29.1 13.9 | 27.3 27.3 34.8 46.7 | 11.5 10.1 10.1 6.47 |
The present invention has following features:
1. methane conversion to the conversion per pass of formaldehyde reaches 9～11%, reaches as high as 12～13%, head and shoulders above present domestic and international about 3% level.
2. the flow process designed according to inventive concept has the function of membrane reactor, and it can make the product that originally was difficult in the low equilibrium conversion of industrial realization, obtains to be higher than the productive rate of equilibrium concentration, thereby makes it to realize in industrial production. It is not only applicable to one step of the contained natural gas of the present invention formaldehyde processed, can be effective to the reaction of other low equilibrium conversion yet.
3. this method formaldehyde flow process of producing is short, cost is low.
Claims (3)
1. Sweet natural gas is directly made the method for formaldehyde, be to be that homogeneous catalyst, borax are heterogeneous catalyst with the nitrogen protoxide, it is characterized in that: 1. add water vapour before unstripped gas enters reactor, 2. in reaction zone, the bottom uses spiral coil cooling tube with the indirect quenching of tap water.
2. according to the prepared formaldehyde method of claim 1, it is characterized in that reaction conditions is: air: methane=(1～4): 1, feed gas flow rates is 50～300ml/min, temperature of reaction is 600～750 ℃, content of nitric oxide is 1～9% in the unstripped gas, water vapour and unstripped gas (air, methane, nitrogen protoxide) add reaction zone simultaneously, and the add-on of water vapour is counted 0.5～3ml/min by liquid water.
3. according to claim 1,2 prepared formaldehyde method, it is characterized in that the quenching mode of said reaction zone middle and lower part, its method be inner with tap water refrigerative serpentine tube directly insert people's reaction zone in, the bottom.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94111961A CN1039584C (en) | 1994-11-05 | 1994-11-05 | Direct method for prodn. of formaldehyde using natural gas as raw material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94111961A CN1039584C (en) | 1994-11-05 | 1994-11-05 | Direct method for prodn. of formaldehyde using natural gas as raw material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1122796A CN1122796A (en) | 1996-05-22 |
| CN1039584C true CN1039584C (en) | 1998-08-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN94111961A Expired - Fee Related CN1039584C (en) | 1994-11-05 | 1994-11-05 | Direct method for prodn. of formaldehyde using natural gas as raw material |
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| CN (1) | CN1039584C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104447249A (en) * | 2013-09-17 | 2015-03-25 | 乐山师范学院 | New technology for preparing formaldehyde by directly oxidizing methane |
| EP3517204A1 (en) * | 2018-01-26 | 2019-07-31 | Nederlandse Organisatie voor toegepast- natuurwetenschappelijk onderzoek TNO | Reactor and process for the hydrogenation of carbon dioxide |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1011627A1 (en) * | 1981-07-14 | 1983-04-15 | Институт Теоретических Проблем Химической Технологии Ан Азсср | Process for producing formaldehyde |
| SU1014825A1 (en) * | 1981-07-03 | 1983-04-30 | Институт Теоретических Проблем Химической Технологии Ан Азсср | Process for preparing formaldehyde |
-
1994
- 1994-11-05 CN CN94111961A patent/CN1039584C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1014825A1 (en) * | 1981-07-03 | 1983-04-30 | Институт Теоретических Проблем Химической Технологии Ан Азсср | Process for preparing formaldehyde |
| SU1011627A1 (en) * | 1981-07-14 | 1983-04-15 | Институт Теоретических Проблем Химической Технологии Ан Азсср | Process for producing formaldehyde |
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|---|---|
| CN1122796A (en) | 1996-05-22 |
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