CN204999870U

CN204999870U - Methyl alcohol synthetic LNG device of methanation of speeding to exit

Info

Publication number: CN204999870U
Application number: CN201520713154.5U
Authority: CN
Inventors: 纪志愿; 孙健; 孙新升; 徐占杰; 余浩; 程云飞
Original assignee: Shanghai Huaxi Chemical Science & Technology Co Ltd
Current assignee: Anhui East China Chemical and Medical Engineering Co., Ltd.
Priority date: 2015-09-15
Filing date: 2015-09-15
Publication date: 2016-01-27
Anticipated expiration: 2025-09-15

Abstract

The utility model discloses a methyl alcohol synthetic LNG device of methanation of speeding to exit, including helical -lobe compressor, split -compressor and methanator, helical -lobe compressor connects split -compressor, has connected gradually heat exchanger and deoxidation reactor between split -compressor and the methanator, and methanator's export has connected gradually heat exchanger, desalinized water pre -heater, cooler and knockout drum, is connected with multi -stage compressor on the knockout drum. The utility model discloses the device flow is short, and this manufacturing equipment is few, and the investment practices thrift 70%, and the reactor is small in quantity, need not the recycle compressor, also need not waste boiler, needs the parameter of control few, the operation of being convenient for, and also easily the engineering is implemented, and the pressure of system's device is low, and the single unit system energy consumption reduces 15 -20%.

Description

A kind of methanol purge gas methanation synthesis LNG device

Technical field

The utility model relates to the recovery and utilization technology field of methyl alcohol, specifically a kind of methanol purge gas methanation synthesis LNG device.

Background technology

China is the country that world methanol output is maximum, accounts for 40% of global methanol output, and often produces one ton of methyl alcohol and will to have an appointment 100Nm ³byproduct methanol purge gas produce, output is huge, becomes a kind of large-tonnage energy and chemical resource gradually.

Its composition of methanol purge gas is slightly difference because methanol synthesizing process process condition is different, generally contain the hydrogen of about 64%, the methane of about 10%, the carbon monoxide of about 9%, also contain the carbonic acid gas of about 5% in addition, trace unsaturated hydrocarbons, the carbonic acid gas of about 13%, other gas of about 1%.Traditional treatment process is mainly as the combustion heating of self, and for the consideration of keeping the safety in production, methanol purge gas more than needed is then directly discharged in air after burning, not only pollutes environment but also cause great waste, brings great threat also to the living environment of the mankind.Therefore, how efficiently, reasonably utilize methanol purge gas to be the key subjects of relation environmental protection, comprehensive utilization of resources, energy-saving and emission-reduction, between nearest decades, obtained everybody showing great attention to.

Methanation technology is one of gordian technique of methanol purge gas LNG, and the methanation reaction usually in industry generation has two kinds: one is for the synthesis of in ammonia and device for producing hydrogen, by oxycarbide (CO+CO a small amount of in synthetic gas under catalyst action ₂<0.7%) methane of water and inertia is generated with H-H reaction, to eliminate the impact of oxycarbide on subsequent handling catalyzer.Another kind is the methanation in synthetic natural gas process, the oxycarbide (CO+CO in its unstripped gas ₂) concentration is higher.

Following several process unit is mainly taked in the production of methanation both at home and abroad at present.

1, adiabatic multi-stage fixed-bed circulation technology device

This process unit be by one section or two sections of methanations after process gas be circulated to one section of methanation entrance, enter the CO+CO of one section of methanation with " dilution " ₂content, schematic diagram as shown in Figure 1.But the recycle ratio in this circulation technology device is comparatively large, and energy consumption is higher, and required recycle compressor adds the gross investment of methanation process.

2, adiabatic multi-stage fixed-bed " once passing through " process unit

As shown in Figure 2, this process unit is comparatively simple, and energy consumption is lower, can by-product high-quality steam; Without the need to recycle compressor, can greatly reduce investment outlay.But this process unit requires higher to catalyzer and reactor, needs to add relatively large steam (>=15%vol), adds operation difficulty.

3, one section, West China, Shanghai isothermal methanation device

West China, Shanghai develops one section of special isothermal shell and tube methanator specially.Methanation catalyst is contained in tube side, and water is at shell side.When reacting, by the boiling heat extraction of high pressure water, control the temperature rise of methanation reaction.Because isothermal shell-and-tube reactor can make methanation run at a lower temperature, ensure that CO, CO ₂higher conversion.In addition, this reactor also solves the too high problem of catalyzer hot(test)-spot temperature.

Current domestic adiabatic multistage methanation process and device are also in the development phase, also immature.As CO+CO in methanol purge gas ₂when>=12%, adiabatic multi-stage fixed-bed technique is for CO ₂low conversion rate, carbon distribution cause that methanation catalyst is frequently changed etc. problem occur at different device.

Utility model content

The purpose of this utility model is to provide a kind of methanol purge gas methanation to synthesize LNG device, to solve the problem proposed in above-mentioned background technology.

For achieving the above object, the utility model provides following technical scheme:

A kind of methanol purge gas methanation synthesis LNG device, comprise spiral-lobe compressor, two stage compressor and methanator, described spiral-lobe compressor connects two stage compressor, interchanger and deoxidation reactor is connected with in turn between described two stage compressor and methanator, the outlet of described methanator is connected with interchanger, de-salted water preheater, water cooler and separating tank in turn, and described separating tank is connected with multi-stage compressor.

As further program of the utility model: described methanator is adiabatic methanation reactor.

Compared with prior art, the beneficial effects of the utility model are:

1, this device flow process is short, and this processing unit is few, investment saving 70%, and only have a methanator and a drum, reactor quantity is few, and without the need to recycle compressor, also without the need to useless pot, need the parameter of control few, convenient operation, is also easy to engineering construction.

2, the pressure of system and device is lower than 1.5MPa, and single unit system energy consumption reduces 15-20%;

3, by this device, CO transformation efficiency>=99.95% is made, CO ₂transformation efficiency>=99.9%, reactor outlet CO+CO ₂<50ppm, without the need to increasing MDEA decarbonization process after methanation.

Accompanying drawing explanation

Fig. 1 is that adiabatic multistage is with fixed bed circulation technology flow path device figure.

Fig. 2 is adiabatic multi-stage fixed-bed " once passing through " technological process device figure.

Fig. 3 is technological process device figure of the present utility model.

In figure: 1-spiral-lobe compressor; 2-two stage compressor; 3-methanator; 4-interchanger; 5-deoxidation reactor; 6-de-salted water preheater; 7-water cooler; 8-separating tank; 9-multi-stage compressor.

Embodiment

Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.

Refer to Fig. 3, in the utility model embodiment, a kind of methanol purge gas methanation synthesis LNG device, comprise spiral-lobe compressor 1, two stage compressor 2 and methanator 3, spiral-lobe compressor 1 connects two stage compressor 2, be connected with interchanger and 4 deoxidation reactors 5 between two stage compressor 2 and methanator 3 in turn, the outlet of methanator 3 is connected with interchanger 4, de-salted water preheater 6, water cooler 7 and separating tank 8 in turn, separating tank 8 is connected with multi-stage compressor 9.

The workflow of this methanol purge gas methanation synthesis LNG device

(1) be first forced into 0.2 ~ 0.3MPa through spiral-lobe compressor from the methanol purge gas outside battery limit (BL), and then be compressed to 1.2 ~ 1.5MPa through two stage compressor, after heat exchange, enter deoxidation reactor carry out deoxygenation, enter follow-up methanation operation;

(2) enter methanator through the methanol purge gas of overdraft to react, carbon monoxide and carbonic acid gas and hydrogen obtain methane and water under the catalyzed reaction of catalyzer, and temperature of reaction controls at 250 ~ 600 DEG C; The temperature out of methanator controls at 330 DEG C, methanator exit gas heats up to the methanol purge gas after purification by interchanger, heat is reclaimed again by de-salted water preheater, normal temperature is dropped to again through water-cooled, then separate the water of methanation reaction generation through separating tank, finally enter follow-up cryogenic liquefying operation;

(3) by gas deep cooling extremely less than-162 DEG C, and compress 625 times, obtain liquid LNG

As shown in Figure 3, the methanol purge gas after purification, mainly containing H ₂, CH ₄, CO, CO ₂, N ₂deng, after being heated up by heat exchange, then enter methanator with 250 ~ 300 DEG C, wherein H in gas after methanation ₂during content >5%, CO transformation efficiency>=99.95%, CO ₂transformation efficiency>=99.9%, reactor outlet CO, CO ₂<50ppm, presses steam in by-product simultaneously.

The treatment process of methanation process device to methanation for different flow process compares, as following table

As can be seen from the above table, one section is waited hotbed methanation device compared with multistage insulation methanation device, has the advantages that technical process is short, technique simple, reactor quantity is few, reduced investment, energy consumption are low, and the utility model plant investment reduces about more than 70%.

The utility model can shift out reaction heat in time, produces middle pressure steam, does not therefore worry the CO+CO in methanol purge gas ₂the problem that content is higher.Even in the company having cheap carbon resource, more CO+CO can also be supplemented ₂, after methanation reaction, produce more CH ₄.

For the methanol device of a set of 400,000 tons/year, the methanol purge gas of its by-product is about 20000m ³n/h, the utility model one section of adiabatic methanation technology produces LNG, and its construction investment is about saved 2,000 ten thousand yuan of power savings and is about 200kwh, and reducing expenses every year is 1,500,000 yuan.

To those skilled in the art, obvious the utility model is not limited to the details of above-mentioned one exemplary embodiment, and when not deviating from spirit of the present utility model or essential characteristic, can realize the utility model in other specific forms.Therefore, no matter from which point, all should embodiment be regarded as exemplary, and be nonrestrictive, scope of the present utility model is limited by claims instead of above-mentioned explanation, and all changes be therefore intended in the implication of the equivalency by dropping on claim and scope are included in the utility model.Any Reference numeral in claim should be considered as the claim involved by limiting.

Claims

1. a methanol purge gas methanation synthesis LNG device, comprise spiral-lobe compressor, two stage compressor and methanator, it is characterized in that, described spiral-lobe compressor connects two stage compressor, interchanger and deoxidation reactor is connected with in turn between described two stage compressor and methanator, the outlet of described methanator is connected with interchanger, de-salted water preheater, water cooler and separating tank in turn, and described separating tank is connected with multi-stage compressor.

2. methanol purge gas methanation synthesis LNG device according to claim 1, it is characterized in that, described methanator is adiabatic methanation reactor.