CN102757324A - Method for producing formaldehyde from methanol under oxygen-rich condition and utilizing formaldehyde exhaust gas - Google Patents

Method for producing formaldehyde from methanol under oxygen-rich condition and utilizing formaldehyde exhaust gas Download PDF

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CN102757324A
CN102757324A CN2012101597504A CN201210159750A CN102757324A CN 102757324 A CN102757324 A CN 102757324A CN 2012101597504 A CN2012101597504 A CN 2012101597504A CN 201210159750 A CN201210159750 A CN 201210159750A CN 102757324 A CN102757324 A CN 102757324A
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formaldehyde
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methanol
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CN102757324B (en
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王琳
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Shanxi Yangmei Fengxi Fertilizer Industry (Group) Co Ltd
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Shanxi Yangmei Fengxi Fertilizer Industry (Group) Co Ltd
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Abstract

The invention discloses a method for producing formaldehyde from methanol under oxygen-rich conditions and utilizing a formaldehyde exhaust gas, belongs to the technical field of chemical production and relates to a formaldehyde production method. The method comprises the following steps: feeding gasified methanol into a mixer; mixing air and oxygen (volume concentration of 35%) and then preheating to obtain oxygen-rich air which is fed into the mixer, wherein the oxygen (volume concentration of 35%) is obtained by producing oxygen through air separation and mixing with the air or obtained by mixing the air with the gas resulting from nitrogen removal through pressure-variable adsorption; feeding steam into the mixer, wherein the volume ratio of methanol gas to oxygen-rich air to steam is 3:4.4:1; and allowing the reaction to take place among the gases, cooling the gases and feeding into an absorption tower where a formaldehyde finished product and a formaldehyde exhaust gas are produced, feeding a part of the formaldehyde exhaust gas into the mixer for recycling use, feeding another part of the formaldehyde exhaust gas into a synthetic ammonia gas making furnace where the formaldehyde exhaust gas is mixed with water gas and the mixture serves as a raw gas of synthetic ammonia. The method is simple, reduces the quantity of the produced exhaust gases, reduces the energy consumption of the whole process, and has significant economic benefits.

Description

A kind of methyl alcohol oxygen enrichment is produced formaldehyde and formaldehyde waste gas utilization method
Technical field
The invention belongs to chemical production technical field, relate to the Formaldehyde Production method, be specifically related to a kind of methyl alcohol oxygen enrichment and produce formaldehyde and formaldehyde waste gas utilization method.
Background technology
Produce formaldehyde in the industry and mainly adopt the methyl alcohol air oxidation process, be divided into silver-colored Catalytic processes and iron-molybdenum oxide Catalytic processes, abbreviate Yin Fa and iron molybdenum method as by its used catalyzer difference.
1, silver catalyst method
The silver method is the main method of producing formaldehyde in early days; This method is to make catalyzer with silver; Methyl alcohol and AIR MIXTURES are raw material, are being higher than the limits of explosion upper limit (> 37%) situation under, in fixed-bed reactor, carry out catalytic oxidation and generate formaldehyde; Temperature of reaction is between 550~650 ℃, and reaction gas makes 37% formaldehyde solution after absorbing processing.
Its main chemical reactions has:
Oxidizing reaction:
CH 3OH?+?0.5?O 2?→?CH 2O?+?H2O △H=-157.2kJ/mol
Dehydrogenation reaction:
CH 3OH?→?CH 2O?+?H 2 △H=85kJ/mol
Except that above-mentioned methanol oxidation and dehydrogenation reaction take place, also have a small amount of side reactions generations such as methane, carbon monoxide, carbonic acid gas, formic acid that generate.
Because the catalyzer method of manufacture that adopts is different with form, can be divided into silver gauze again, float stone is silver-colored, crystallization is silver-colored and method such as electrolytic silver, wherein best with the performance of catalyst for electrolytic silver, the yield of formaldehyde can reach 87%.
2, iron-molybdic catalyst method
Iron molybdenum method is a kind of novel method of producing formaldehyde that grows up nearly decades; This method is to make catalyzer with MOXs such as molybdenum-irons; Methanol concentration is lower than under the condition of lower explosive limit; Methyl alcohol and excess air are under 280~340 ℃, and through the calandria type fixed bed oxidation generation formaldehyde that carries out of catalyzer is housed, reaction mixture gas can make the concentrated formaldehyde solution more than 50% after absorbing.
Its main chemical reactions formula is following:
CH3OH?+?0.5?O 2?→?CH 2O?+?H2O △H=-157.2KJ/mol
CH 3OH?+?O 2?→?CO?+?2?H 2O △H=-383.8KJ/mol
Adopt iron molybdenum method can obtain 97% transformation efficiency and higher selectivity, produce the high-concentration formaldehyde that contains low alcohol.
For method 1, adopt the tail gas circulation can produce high-concentration formaldehyde, can produce the formaldehyde of low pure content through the methanol loop method, owing to adopt air to originate as oxygen, it is too high and can't effectively utilize to cause the tail gas internal circulating load to reach in the tail gas nitrogen content greatly.For method 2, compare the investment of silver-colored method be twice above, long flow path, power consumption is high, hydrogen not in the tail gas can't fully utilize.
Summary of the invention
The present invention is in order to solve the problem that above-mentioned prior art exists, and provides a kind of methyl alcohol oxygen enrichment to produce formaldehyde and formaldehyde waste gas utilization method.
The present invention realizes through following technical scheme:
A kind of methyl alcohol oxygen enrichment is produced formaldehyde and formaldehyde waste gas utilization method, may further comprise the steps:
(1) methanol gasifying: methyl alcohol is sent into mixing tank after the reboiler gasification, the methanol solution pump around circuit of reboiler bottom is to the reboiler bottom;
(2) preheating oxygen-rich air: air after will filtering and volumetric concentration are to be preheating to 110 ℃ of temperature after the oxygen mix of 35% concentration; Obtain oxygen-rich air; Send into mixing tank then; The volume ratio of the oxygen of its air and 35% concentration is 3:1, and wherein 35% concentration oxygen is joined air by making oxygen by air separation and produced, or carries gas behind the nitrogen by transformation absorption and allocate in the air and produce;
(3) gas mixes: steam is regulated flow by variable valve get into mixing tank after vapour distributor filters, and the gas that obtains mixing, wherein the volume ratio of methanol gas, oxygen-rich air, steam is 3:4.4:1 in the mixing tank;
(4) filter oxidation: behind strainer elimination impurity, send in the oxidizer that catalyzer is housed through spark arrester again the gas that mixes; Gas is from top to bottom through the catalyst layer in the oxidizer; Oxidization of methanol and dehydrogenation reaction take place under the effect of high temperature and catalyzer; Generate formaldehyde gas and other hot gass, wherein temperature is 580 ~ 650 ℃, and catalyzer is a silver catalyst;
(5) absorb: the gas that generates in the oxidizer is carried out quenching through the quench zone that is close to oxidizer rapidly; Be cooled to below 90 ℃; Send in the absorption tower then and absorb; Generate formaldehyde finished product and formaldehyde tail gas, a formaldehyde tail gas part is sent into mixing tank and is recycled, and a part is sent into the ammonia stove and mixed as syngas for synthetic ammonia with water-gas.
Adopt transformations absorption to carry gas behind the nitrogen with 60,000 tons of/year formaldehyde plants and allocate air into to do raw material be example, implement this inventive method, wherein:
1, reduce air flow quantity through improving the concentration of advancing oxygen, it is 5000 Nm that traditional technology needs air flow quantity 3/ h, the present invention is owing to adopted oxygen-rich air to do raw material, and total gas flow is 4000 Nm 3/ h compares traditional technology and has reduced by 1000 Nm 3/ h through measuring and calculating, reduces the blower fan power consumption more than 10%;
2, the air flow quantity minimizing causes producing the minimizing of tail gas amount, and loop tail tolerance also reduces, and reduces the energy consumption of whole technology; Adopt after this method tail gas amount and composition and conventional silver method to produce the formaldehyde contrast, see table 1;
The traditional Formaldehyde Production method of table 1 and this technology Formaldehyde Production method tail gas synopsis
Figure DEST_PATH_IMAGE001
3, the content of nitrogen reduces in the formaldehyde tail gas, total available gas CO+H 2Content increases to 19.95%, than the CO+H of traditional technology 2Content is high by 3.75%, and the combustion heat value of unit volume increases;
4, adopt fixed bed intermittent gasification explained hereafter syngas for synthetic ammonia, the virgin gas of this technology is called semi-water gas again, and the mixing of water-gas and air gas (the recovery gas during blowing) is semi-water gas, and the composition of water-gas is seen table 2,
The composition of table 2 water-gas
Title CO 2 CO H 2 N 2 O 2, CH4 etc.
Content % 6 36 52 6 On a small quantity
Air gas composition, see Table 3,
The composition of table 3 air gas
Title CO 2 CO H 2 N 2 O 2, CH4 etc.
Content % 15 7 4 74 On a small quantity
According to table 3 data, reclaim the total effective constituent CO+H of gas in the gas 2Be 11%, total available gas CO+H in the formaldehyde tail gas 2Content 19.95%, the ultra available gas content 8.95% that reclaims in the gas of this content, the calorific value of formaldehyde tail gas is higher than the calorific value that gas is reclaimed in blowing, CO 2Be the invalid gas of synthetic ammonia, CO in the formaldehyde tail gas 2Content has only 30% of recovery gas, therefore, replaces air gas (recovery gas) to mix with water-gas with formaldehyde tail gas and produces syngas for synthetic ammonia, with the quality that obviously improves virgin gas.
Compared with prior art, technology of the present invention is simple, reduces air flow quantity through improving the concentration of advancing oxygen; The air flow quantity minimizing causes producing the tail gas amount and reduces, and loop tail tolerance also reduces, and reduces the energy consumption of whole technology; Have remarkable economic efficiency, be fit to promote the use of.
Description of drawings
Fig. 1 is a process flow diagram of the present invention.
Embodiment
Embodiment 1
A kind of methyl alcohol oxygen enrichment is produced formaldehyde and formaldehyde waste gas utilization method, may further comprise the steps:
(1) methanol gasifying: methyl alcohol is sent into mixing tank after the reboiler gasification, the methanol solution pump around circuit of reboiler bottom is to the reboiler bottom;
(2) preheating oxygen-rich air: air after will filtering and volumetric concentration are to be preheating to 110 ℃ of temperature after the oxygen mix of 35% concentration; Obtain oxygen-rich air; Send into mixing tank then; The volume ratio of the oxygen of its air and 35% concentration is 3:1, and wherein 35% concentration oxygen is joined air by making oxygen by air separation and produced, or carries gas behind the nitrogen by transformation absorption and allocate in the air and produce;
(3) gas mixes: steam is regulated flow by variable valve get into mixing tank after vapour distributor filters, and the gas that obtains mixing, wherein the volume ratio of methanol gas, oxygen-rich air, steam is 3:4.4:1 in the mixing tank;
(4) filter oxidation: behind strainer elimination impurity, send in the oxidizer that catalyzer is housed through spark arrester again the gas that mixes; Gas is from top to bottom through the catalyst layer in the oxidizer; Oxidization of methanol and dehydrogenation reaction take place under the effect of high temperature and catalyzer; Generate formaldehyde gas and other hot gass, wherein temperature is 580 ~ 600 ℃, and catalyzer is a silver catalyst;
(5) absorb: the gas that generates in the oxidizer is carried out quenching through the quench zone that is close to oxidizer rapidly; Be cooled to 90 ℃; Send in the absorption tower then and absorb; Generate formaldehyde finished product and formaldehyde tail gas, a formaldehyde tail gas part is sent into mixing tank and is recycled, and a part is sent into the ammonia stove and mixed as syngas for synthetic ammonia with water-gas.
Process flow sheet is as shown in Figure 1.
Embodiment 2
A kind of methyl alcohol oxygen enrichment is produced formaldehyde and formaldehyde waste gas utilization method, may further comprise the steps:
(1) methanol gasifying: methyl alcohol is sent into mixing tank after the reboiler gasification, the methanol solution pump around circuit of reboiler bottom is to the reboiler bottom;
(2) preheating oxygen-rich air: air after will filtering and volumetric concentration are to be preheating to 110 ℃ of temperature after the oxygen mix of 35% concentration; Obtain oxygen-rich air; Send into mixing tank then; The volume ratio of the oxygen of its air and 35% concentration is 3:1, and wherein 35% concentration oxygen is joined air by making oxygen by air separation and produced, or carries gas behind the nitrogen by transformation absorption and allocate in the air and produce;
(3) gas mixes: steam is regulated flow by variable valve get into mixing tank after vapour distributor filters, and the gas that obtains mixing, wherein the volume ratio of methanol gas, oxygen-rich air, steam is 3:4.4:1 in the mixing tank;
(4) filter oxidation: behind strainer elimination impurity, send in the oxidizer that catalyzer is housed through spark arrester again the gas that mixes; Gas is from top to bottom through the catalyst layer in the oxidizer; Oxidization of methanol and dehydrogenation reaction take place under the effect of high temperature and catalyzer; Generate formaldehyde gas and other hot gass, wherein temperature is 600 ~ 630 ℃, and catalyzer is a silver catalyst;
(5) absorb: the gas that generates in the oxidizer is carried out quenching through the quench zone that is close to oxidizer rapidly; Be cooled to 85 ℃; Send in the absorption tower then and absorb; Generate formaldehyde finished product and formaldehyde tail gas, a formaldehyde tail gas part is sent into mixing tank and is recycled, and a part is sent into the ammonia stove and mixed as syngas for synthetic ammonia with water-gas.
Embodiment 3
A kind of methyl alcohol oxygen enrichment is produced formaldehyde and formaldehyde waste gas utilization method, may further comprise the steps:
(1) methanol gasifying: methyl alcohol is sent into mixing tank after the reboiler gasification, the methanol solution pump around circuit of reboiler bottom is to the reboiler bottom;
(2) preheating oxygen-rich air: air after will filtering and volumetric concentration are to be preheating to 110 ℃ of temperature after the oxygen mix of 35% concentration; Obtain oxygen-rich air; Send into mixing tank then; The volume ratio of the oxygen of its air and 35% concentration is 3:1, and wherein 35% concentration oxygen is joined air by making oxygen by air separation and produced, or carries gas behind the nitrogen by transformation absorption and allocate in the air and produce;
(3) gas mixes: steam is regulated flow by variable valve get into mixing tank after vapour distributor filters, and the gas that obtains mixing, wherein the volume ratio of methanol gas, oxygen-rich air, steam is 3:4.4:1 in the mixing tank;
(4) filter oxidation: behind strainer elimination impurity, send in the oxidizer that catalyzer is housed through spark arrester again the gas that mixes; Gas is from top to bottom through the catalyst layer in the oxidizer; Oxidization of methanol and dehydrogenation reaction take place under the effect of high temperature and catalyzer; Generate formaldehyde gas and other hot gass, wherein temperature is 590 ~ 610 ℃, and catalyzer is a silver catalyst;
(5) absorb: the gas that generates in the oxidizer is carried out quenching through the quench zone that is close to oxidizer rapidly; Be cooled to 70 ℃; Send in the absorption tower then and absorb; Generate formaldehyde finished product and formaldehyde tail gas, a formaldehyde tail gas part is sent into mixing tank and is recycled, and a part is sent into the ammonia stove and mixed as syngas for synthetic ammonia with water-gas.

Claims (1)

1. a methyl alcohol oxygen enrichment is produced formaldehyde and formaldehyde waste gas utilization method, it is characterized in that may further comprise the steps:
(1) methanol gasifying: methyl alcohol is sent into mixing tank after the reboiler gasification, the methanol solution pump around circuit of reboiler bottom is to the reboiler bottom;
(2) preheating oxygen-rich air: air after will filtering and volumetric concentration are to be preheating to 110 ℃ of temperature after the oxygen mix of 35% concentration; Obtain oxygen-rich air; Send into mixing tank then; The volume ratio of the oxygen of its air and 35% concentration is 3:1, and wherein 35% concentration oxygen is joined air by making oxygen by air separation and produced, or carries gas behind the nitrogen by transformation absorption and allocate in the air and produce;
(3) gas mixes: steam is regulated flow by variable valve get into mixing tank after vapour distributor filters, and the gas that obtains mixing, wherein the volume ratio of methanol gas, oxygen-rich air, steam is 3:4.4:1 in the mixing tank;
(4) filter oxidation: behind strainer elimination impurity, send in the oxidizer that catalyzer is housed through spark arrester again the gas that mixes; Gas is from top to bottom through the catalyst layer in the oxidizer; Oxidization of methanol and dehydrogenation reaction take place under the effect of high temperature and catalyzer; Generate formaldehyde gas and other hot gass, wherein temperature is 580 ~ 650 ℃, and catalyzer is a silver catalyst;
(5) absorb: the gas that generates in the oxidizer is carried out quenching through the quench zone that is close to oxidizer rapidly; Be cooled to below 90 ℃; Send in the absorption tower then and absorb; Generate formaldehyde finished product and formaldehyde tail gas, a formaldehyde tail gas part is sent into mixing tank and is recycled, and a part is sent into the ammonia stove and mixed as syngas for synthetic ammonia with water-gas.
CN201210159750.4A 2012-05-22 2012-05-22 Method for producing formaldehyde from methanol under oxygen-rich condition and utilizing formaldehyde exhaust gas Expired - Fee Related CN102757324B (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104016318A (en) * 2014-06-19 2014-09-03 昆明冶金研究院 Combined carbon reducing agent for yellow phosphorus production and preparation method of combined carbon reducing agent
CN111253229A (en) * 2020-03-31 2020-06-09 山东明化新材料有限公司 Formaldehyde pyridine hydrogen peroxide coproduction method
CN113200827A (en) * 2021-05-19 2021-08-03 宁夏华业精细化学科技有限公司 Paraformaldehyde production process

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104016318A (en) * 2014-06-19 2014-09-03 昆明冶金研究院 Combined carbon reducing agent for yellow phosphorus production and preparation method of combined carbon reducing agent
CN104016318B (en) * 2014-06-19 2016-02-10 昆明冶金研究院 A kind of phosphorus production combination charcoal element reductive agent and preparation method thereof
CN111253229A (en) * 2020-03-31 2020-06-09 山东明化新材料有限公司 Formaldehyde pyridine hydrogen peroxide coproduction method
CN111253229B (en) * 2020-03-31 2022-08-30 山东明化新材料有限公司 Formaldehyde pyridine hydrogen peroxide coproduction method
CN113200827A (en) * 2021-05-19 2021-08-03 宁夏华业精细化学科技有限公司 Paraformaldehyde production process

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