CN105218334A - A kind of prepn. of formaldehyde - Google Patents
A kind of prepn. of formaldehyde Download PDFInfo
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- CN105218334A CN105218334A CN201510796733.5A CN201510796733A CN105218334A CN 105218334 A CN105218334 A CN 105218334A CN 201510796733 A CN201510796733 A CN 201510796733A CN 105218334 A CN105218334 A CN 105218334A
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- formaldehyde
- gas
- absorption tower
- steam
- methyl alcohol
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
- C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
- C07C45/37—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups
- C07C45/38—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups being a primary hydroxyl group
Abstract
The invention provides a kind of prepn. of formaldehyde, comprise following operation: evaporation, gas operation processed, the obtained quaternary mixed gas meeting procedure technology requirement; Oxidation operation: carry out the oxidation of methyl alcohol, dehydrogenation reaction under the effect of catalyst for electrolytic silver, is formaldehyde by methanol conversion and produces a small amount of by product; Absorb operation: in packed absorber with water and formaldehyde solution for absorption agent, absorb through continuous countercurrent and make industrial formaldehyde solution.The present invention can make full use of circulation of tail gas and make formaldehyde, and raw material availability is high, and seldom produces refuse.
Description
Technical field
The invention belongs to chemical production technical field, relate generally to a kind of prepn. of formaldehyde making full use of production tail gas.
Background technology
Domestic current Formaldehyde Production enterprise has exceeded 5000, and aggregated capacity is about 3,200 ten thousand tons.Because formaldehyde Technology is updated, formaldehyde is developed into " aerogenesis type " by former " consumption vapour type ", and namely formaldehyde plant all can realize byproduct steam.Wherein formaldehyde plant steams o'clock primarily of two, and one is utilize the thermogenetic 0.4MPa steam of the reaction of oxidizer, and two is the steam of the pressure controllable that the heat of the exhaust combustion utilizing formaldehyde plant produces, and normally produces 0.8MPa.Simultaneously in formaldehyde production, in oxidation reactor, also need supplementary steam as reaction feed, in this step, require that the steam entered in reactor is 0.15MPa.The steam pressure-reducing of the 0.4MPa steam produced in formaldehyde reaction device or 0.8MPa is normally sent into reactor and is carried out batching steam by current Formaldehyde Production enterprise to 0.15MPa, causes high pressure steam energy directly to waste; And the Formaldehyde Production producer byproduct steam part of domestic formaldehyde industry, because vapor pressure is lower, use value is lower, so byproduct steam removes outside domestic water heating substantially, it is all direct emptying process, not only noise is large, and energy wastage is very serious, does not meet the expectation that national energy-saving reduces discharging.
Summary of the invention
For solving the problems of the technologies described above, the invention provides a kind of prepn. of formaldehyde, it comprises the following steps:
Methyl alcohol is passed into methyl alcohol reboiler, then the methanol gasifying made wherein is heated to described methyl alcohol reboiler, and then by passing into quaternary gas mixer after mist eliminator precipitation of liquid droplets, simultaneously pass into hot steam to described quaternary gas mixer, add warm air and heating after tail gas;
Mixed quaternary gas is equipped with in the oxidizer of catalyzer by passing into after filtration, heat described oxidizer, then the mixed gas after oxidation is cooled by cooling soft water, passed into successively in the first absorption tower, second absorption tower by cooled mixed gas and absorb, described second absorption tower receives liquid by pump for described first absorption tower provides rare formaldehyde; Be not divided into two-way by the tail gas that described second absorption tower absorbs, pass into described quaternary gas mixer after a road heating, separately lead up to combustion heating water generates steam;
Described first absorption tower is connected with formaldehyde tundish, and the formaldehyde solution meeting concentration of formaldehyde pumps in described formaldehyde tundish and stores by described first absorption tower.
Preferably, described heating steam, add warm air and heating after tail gas heated by steam, described steam is generated by drum, described drum Raw water is the hot water that the mixed gas after cooling oxidation produces, and the steam that described second absorption tower combustion heating water produces passes into described drum.
Preferably, the steam that described drum generates is dispensed to airheater, vapor filter, heater exhaust gas and methyl alcohol reboiler by vapour distributor.
Preferably, then described quaternary mixed gas first enters oxidizer through spark arrester after purification, contacts at the temperature of about 650 DEG C with silver catalyst.
The present invention has following beneficial effect:
With reference to the description to beneficial effect in specific embodiment.
Certainly, implement arbitrary product of the present invention might not need to reach above-described all advantages simultaneously.
Accompanying drawing explanation
In order to be illustrated more clearly in the technical scheme of the embodiment of the present invention, be briefly described describing the required accompanying drawing used to embodiment below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
The prepn. of formaldehyde schematic flow sheet that Fig. 1 provides for the embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making other embodiments all obtained under creative work prerequisite, belong to the scope of protection of the invention.
As shown in Figure 1, embodiments provide a kind of prepn. of formaldehyde, it comprises the following steps:
Methyl alcohol is passed into methyl alcohol reboiler, then the methanol gasifying made wherein is heated to described methyl alcohol reboiler, and then by passing into quaternary gas mixer after mist eliminator precipitation of liquid droplets, simultaneously pass into hot steam to described quaternary gas mixer, add warm air and heating after tail gas;
Mixed quaternary gas is equipped with in the oxidizer of catalyzer by passing into after filtration, heat described oxidizer, then the mixed gas after oxidation is cooled by cooling soft water, passed into successively in the first absorption tower, second absorption tower by cooled mixed gas and absorb, described second absorption tower receives liquid by pump for described first absorption tower provides rare formaldehyde; Be not divided into two-way by the tail gas that described second absorption tower absorbs, pass into described quaternary gas mixer after a road heating, separately lead up to combustion heating water generates steam;
Described first absorption tower is connected with formaldehyde tundish, and the formaldehyde solution meeting concentration of formaldehyde pumps in described formaldehyde tundish and stores by described first absorption tower.
The idiographic flow of the formaldehyde production technology that the present embodiment provides is:
Methyl alcohol squeezes into reboiler from methyl alcohol tundish by methanol pump; Enter bottom reboiler from methyl alcohol tundish methyl alcohol out by after governor valve control flow; Reboiler shell side heats by from drum and through the heating steam of governor valve control the methanol gasifying made in reboiler simultaneously, methyl alcohol gas in methanol evaporator from vaporizer top after mesh mist eliminator precipitation of liquid droplets, enter quaternary gas mixer through the pipeline with steam jacket pipe, the methanol solution pump around circuit in vaporizer is bottom reboiler.The air come from air filter sends into airheater by Root's blower, after preheating, enter mixing tank, and batching steam enters mixing tank by variable valve adjust flux from vapour distributor after vapor filter filters.
After normal driving, after exhaust gas circulation system is first qualified with tail gas displacement, opens tail gas gas blower and the partial tail gas after well heater preheating is sent into mixing tank.Quaternary gas Homogeneous phase mixing in mixing tank, then through strainer further cross elimination may with a small amount of impurity after again by spark arrester send into be equipped with in the oxidizer of catalyzer.Reactant gases passes through catalyst layer, and oxidation and the dehydrogenation reaction of methyl alcohol occur under the effect of high temperature and catalyzer, generates formaldehyde gas.For preventing the thermolysis of reaction product, the hot gas of generation carries out quenching by the quench zone be close to oxidizer rapidly, then sends in absorption tower and absorbs.Formaldehyde finished product, by first grade absorption tower extraction, is added by two-level absorption tower top for the supplementary process water absorbing formaldehyde gas; After rare aldehyde liquid pump at the bottom of two-level absorption tower is got, component loops returns in tower the formaldehyde absorbing the first absorption tower and do not absorbed, and another part sends into the supplementary absorption liquid that first order absorption top of tower does the first absorption tower; The unabsorbed tail gas in two-level absorption tower top is separated after moisture through High-efficiency trap, and a road is sent in exhaust gas treating device and burnt, and liberated heat is used for indirectly producing water vapor; Another road tail gas carries out circulation of tail gas via entering production system again through heater exhaust gas preheating after the pressurization of tail gas gas blower.
The technique entering system due to tail gas belongs to quite ripe Technology, embodiment of the present invention circulation of tail gas silver method explained hereafter 50% formaldehyde mainly adopts methyl alcohol excessive, the limits of explosion of methyl alcohol is between 6%-36.5%, exhaust gas circulation process controls methyl alcohol in oxygen than at about 40%-42%, higher than limits of explosion.Wherein the limits of explosion of hydrogen is 4.1%-74.1%, in tail gas after two towers do not absorb completely, the concentration of hydrogen is between 1%-1.5%, through exhaust fan, the tail gas of about 30% is re-used by system, at quaternary gas mixer and air, water vapour, methanol gas mixes, make the concentration of hydrogen well below 1%, in this mixed gas, the concentration of hydrogen is also well below its limits of explosion 4.1%-74.1%, and therefore the suitable ripe safety of system process is entered in the circulation of tail gas, does not need supporting hydrogen gas recovering device.
As shown in Figure 1, the embodiment of the present invention can be analyzed to multiple operation, wherein each specification and main technique controling parameters as follows:
(1) methanol gasifying and quaternary gas and vapor permeation operation
The task of this operation is exactly that oxidizing operation provides the quaternary mixed gas meeting procedure technology and require, comprise methyl alcohol, air, tail gas, the conveying of water vapour and the preparation of gas mixture and gas overheated, filter, the operating process such as back-fire relief.
The conveying of methyl alcohol: the object of the conveying of methyl alcohol is in order to continuous, stable supply methanol evaporator methyl alcohol; The conveying of methyl alcohol realizes by impeller pump.
The conveying of air: the object of air conveying is to provide required oxygen to methanol oxidation continuously, stably, utilizes the components such as the nitrogen in air simultaneously, removes unnecessary reaction heat; Air is obtained from air by gas blower.
Tail gas is carried: the object of tail gas conveying has three.The first, replace water vapour to play thermal barrier; The second, add partial tail gas and reduce the aerial explosive range of methyl alcohol, be conducive to safety in production; 3rd due to the composition of tail gas unique, can concentrated formaldehyde be produced, suppress dehydrogenation reaction, reduce oxygen temperature, reduce negative reaction thus reduction unit consumption.
The conveying of water vapour: the object of moisture vapor transport mainly contains three, one has been the effect of thermal barrier, and two is reduce the explosive range of methyl alcohol in gas mixture, be conducive to safety in production, three is the generations that can prevent from tying carbon reaction, clean silver-colored catalytic bed, extending catalyst work-ing life; Ingredient water steam is supplied by the water vapour of system waste heat by-product.
The preparation of material mixed gas: be ratio of components in order to ensure methyl alcohol, air and water vapour by the object that processing requirement is made into a certain proportion of unstripped gas by methanol-air-water vapour, to meet the requirement of reaction process and safety in production.
Overheated operation: the task of overheated operation controls the temperature of quaternary gas mixture before entering oxidizer, prevents drop, with the activity of guard catalyst.The control of temperature of superheat realizes by the mode of steam indirect heating quaternary gas.
The purification of quaternary gas mixture: the purification object of quaternary gas mixture is the objectionable impurities that will remove in raw material, prevents poisoning of catalyst and loses activity.The purification means of quaternary gas mixture are by quaternary gas by strainer, entrained solid impurity in removing gas.In addition, the clean level of clean conditions on unstripped gas of device (comprising e-quipment and pipe) has important impact.
Concrete methanol gasifying and quaternary gas and vapor permeation flow process are:
Methyl alcohol is carried from methyl alcohol tundish methanol pump, after governor valve control flow, enter reboiler; The reboiler be connected with vaporizer is by making methanol gasifying after steam-heated cal(l)andria, and methanol gas is left vaporizer and entered mixing tank; Air enters mixing tank after sending into heater heats by gas blower, and the unstripped gas leaving mixing tank delivers to oxidizer after fire-retardant filter.
(2) methanol oxidation dehydration processes
The task of this operation is:
Material mixed gas is after purification, control certain flow velocity and enter oxidizer, oxidation, the dehydrogenation reaction of methyl alcohol is carried out under the effect of catalyst for electrolytic silver, be formaldehyde by methanol conversion and produce a small amount of by product, in this process operations, the height that oxidizing temperature controls, the proportion of composing of quaternary gas and the height of catalyst activity, all directly affect transformation efficiency and the specific absorption of methyl alcohol.
This process flow be:
Then quaternary mixed gas first enters oxidizer through spark arrester after purification, contacts at the temperature of about 650 DEG C with silver catalyst; Overwhelming majority methyl alcohol is converted into formaldehyde, and releases a large amount of reaction heat; The high-temperature gas generated is rapidly by the quench zone of oxidizer, its heat carried carries out heat exchange with the soft water from oxidizer gas bag by tubulation wall, the saturated steam of indirect generation enters vapor distributor for production and application, generates product feeding first grade absorption tower and carry out absorption operation after cooling.
(3) formaldehyde mixed gas cooling and absorbing with store operation
This operation task is:
The task of this operation is the formaldehyde gas generated after transforming at oxidation section, in packed absorber with water and formaldehyde solution for absorption agent, absorb through continuous countercurrent and make industrial formaldehyde solution; In this operating unit, the efficiency on absorption tower and the performance quality of cooling system, will directly affect Yield and quality and the raw material consumption of formaldehyde products.
The idiographic flow of this operation is:
From the formaldehyde gas mixture of oxidizer, enter the bottom of first grade absorption tower; Formaldehyde gas is absorbed by circulation fluid top-down in tower, and remaining formaldehyde gas is discharged by tower top, enters second absorption tower and continues to be absorbed; After fully absorbing, the remaining tower top tail gas part containing the gas such as trace formaldehyde, methyl alcohol, CO, CO2, CH4 and N2, H2 is sent in exhaust gas treating device and is burnt, gas high-altitude after burning enters air, liberated heat is for generation of high-pressure steam, and partial tail gas is through the laggard mixing tank recycle of heater heats; The technique soft water of air water needed for being separated in drum, absorbing is sent into by outer tube and is added by two-level absorption tower tower top after spinner-type flowmeter measures, and by regulating amount of water to control finished product concentration; The absorption liquid of first grade absorption tower and two-level absorption tower is all got with recycle pump, continuous circulation spray-absorption in tower is carried out after plate-type heat exchanger cooling, wherein the rare formaldehyde solution of two-level absorption tower redundance enters first grade absorption tower through branch road after regulating, as the supplementary absorption liquid of first grade absorption tower, first grade absorption tower product section then sends into formaldehyde medial launder through branch road.
The disclosed preferred embodiment of the present invention just sets forth the present invention for helping above.Preferred embodiment does not have all details of detailed descriptionthe, does not limit the embodiment that this invention is only described yet.Obviously, according to the content of this specification sheets, can make many modifications and variations.This specification sheets is chosen and is specifically described these embodiments, is to explain principle of the present invention and practical application better, thus makes art technician understand well and to utilize the present invention.The present invention is only subject to the restriction of claims and four corner and equivalent.
Claims (5)
1. a prepn. of formaldehyde, is characterized in that, comprises the following steps:
Methyl alcohol is passed into methyl alcohol reboiler, then the methanol gasifying made wherein is heated to described methyl alcohol reboiler, and then by passing into quaternary gas mixer after mist eliminator precipitation of liquid droplets, simultaneously pass into hot steam to described quaternary gas mixer, add warm air and heating after tail gas;
Mixed quaternary gas is equipped with in the oxidizer of catalyzer by passing into after filtration, heat described oxidizer, then the mixed gas after oxidation is cooled by cooling soft water, passed into successively in the first absorption tower, second absorption tower by cooled mixed gas and absorb, described second absorption tower receives liquid by pump for described first absorption tower provides rare formaldehyde; Be not divided into two-way by the tail gas that described second absorption tower absorbs, pass into described quaternary gas mixer after a road heating, separately lead up to combustion heating water generates steam;
Described first absorption tower is connected with formaldehyde tundish, and the formaldehyde solution meeting concentration of formaldehyde pumps in described formaldehyde tundish and stores by described first absorption tower.
2. prepn. of formaldehyde as claimed in claim 1, it is characterized in that, described heating steam, add warm air and heating after tail gas heated by steam, described steam is generated by drum, described drum Raw water is the hot water that the mixed gas after cooling oxidation produces, and the steam that described second absorption tower combustion heating water produces passes into described drum.
3. prepn. of formaldehyde as claimed in claim 2, is characterized in that, the steam that described drum generates is dispensed to airheater, vapor filter, heater exhaust gas and methyl alcohol reboiler by vapour distributor.
4. prepn. of formaldehyde as claimed in claim 1, is characterized in that, then described quaternary mixed gas first enters oxidizer through spark arrester after purification, contacts at the temperature of about 650 DEG C with silver catalyst.
5. prepn. of formaldehyde as claimed in claim 1, it is characterized in that, described oxidizer has a quench zone, and the heat-eliminating medium for described quench zone is softened in described cooling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510796733.5A CN105218334A (en) | 2015-11-17 | 2015-11-17 | A kind of prepn. of formaldehyde |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510796733.5A CN105218334A (en) | 2015-11-17 | 2015-11-17 | A kind of prepn. of formaldehyde |
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| CN105218334A true CN105218334A (en) | 2016-01-06 |
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| CN201510796733.5A Pending CN105218334A (en) | 2015-11-17 | 2015-11-17 | A kind of prepn. of formaldehyde |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105732342A (en) * | 2016-03-25 | 2016-07-06 | 湖北三江化工有限责任公司 | Formaldehyde production method based on exhaust gas circulating process |
| CN113200838A (en) * | 2021-05-19 | 2021-08-03 | 宁夏华业精细化学科技有限公司 | Formaldehyde production process |
| 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 |
| CN113219919A (en) * | 2021-04-28 | 2021-08-06 | 徐州市广联科技有限公司 | Training system based on oxidation process |
-
2015
- 2015-11-17 CN CN201510796733.5A patent/CN105218334A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105732342A (en) * | 2016-03-25 | 2016-07-06 | 湖北三江化工有限责任公司 | Formaldehyde production method based on exhaust gas circulating process |
| CN113219919A (en) * | 2021-04-28 | 2021-08-06 | 徐州市广联科技有限公司 | Training system based on oxidation process |
| CN113219919B (en) * | 2021-04-28 | 2022-02-08 | 徐州市广联科技有限公司 | Training system based on oxidation process |
| CN113200838A (en) * | 2021-05-19 | 2021-08-03 | 宁夏华业精细化学科技有限公司 | Formaldehyde production process |
| 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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Application publication date: 20160106 |
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