CN2128630Y

CN2128630Y - Apparatus for preparing high-purity hydrogen and nitrogen gases by ammonia digestion

Info

Publication number: CN2128630Y
Application number: CN 92215501
Authority: CN
Inventors: 奚永龙
Original assignee: SHANGHAI CHEMICAL INST MINISTRY OF CHEMICAL INDUSTRY
Current assignee: SHANGHAI CHEMICAL INST MINISTRY OF CHEMICAL INDUSTRY; Shanghai Research Institute of Chemical Industry SRICI
Priority date: 1992-05-04
Filing date: 1992-05-04
Publication date: 1993-03-24
Anticipated expiration: 2002-05-04

Abstract

The utility model relates to an apparatus for preparing high-purity hydrogen and nitrogen gases by ammonia digestion. The impurity contents are that the ammonia is 0.1-20 PPm, oxygen is 0.1-20 PPm and the dew point of water is below-50 DEG in the hydrogen and nitrogen mixture generated by that the liquid ammonia passes an ammonia decomposing furnace, a high temp. Heat exchanger and an adsorption cleaning part. The utility model can be used as the shielding gases of tin bathes in the production lines of float glasses, and can continuously produce the float glasses in economic and qualified. The utility model has the advantages of low energy consumption, low investment, small occupation of land, low running cost and high reliability. The utility model can save 40% energy consumption and the power of 2*10+[6] degrees one year after mounting on the production lines of float glasses, which needs 90Nm+[3] nitrogen gases each hour.

Description

Apparatus for preparing high-purity hydrogen and nitrogen gases by ammonia digestion

The utility model relates to prepare the high pure hydrogen nitrogen mixed gas device a kind of the decomposition with ammonia.

In prior art, the protection gas of WU groove is that nitrogen with water electrolysis hydrogen producing and air mixes mutually in the float glass industrial production, again through purifying.Though can satisfy the needs of float glass.But water electrolysis energy consumption height, every Nm ³The real power consumption of hydrogen is about 6 degree.Apparatus for electrolyzing also exist take up an area of big, investment is high, device start slow, operator are many, the maintenance trouble, easily produce deficiency such as fault, make continuous hydrogen supply be difficult for assurance, thereby influence the continuous production of float glass.Water electrolysis hydrogen producing also will be equipped with huge gas holder and pressure exerting device, has caused unsafe factor.

The preparing hydrogen by ammonia decomposition nitrogen mixed gas is used in metallurgical industry already, but there is deficiency all the time in the issues of temperature compensation of high-temperature heat-exchanging, is not that complex structure is exactly that equipment is huge.The purity of the product gas of cleaner outlet and the reliability of device can not satisfy the requirement of the protection gas of WU groove in the float glass industrial production.

The objective of the invention is to replace water electrolysis hydrogen producing to add the empty nitrogen that divides with the preparing hydrogen by ammonia decomposition nitrogen mixed gas; investment, reduction running expense, the raising float glass industry WU groove reliability of protecting gas in order to reduce hydrogen manufacturing energy consumption, reduction hydrogen generator station make its not only economy but also continuous qualified production float glass.

The present invention utilizes industrial liquefied ammonia to be raw material; steps such as economic ammonia evaporation, heat exchange, ammonia catalytic decomposition, adsorption cleaning; can make high pure hydrogen nitrogen mixed gas continuously; and the protection gas of float glass industry WU groove needs high pure hydrogen nitrogen mixed gas exactly; to prevent that fused WU is oxidized in the WU groove, improve the quality of float flat glass.

Ammonia decomposes used catalyzer two classes, one class is a ferrum-based catalyst, working temperature is low to be no more than 600 ℃, the rate of decomposition of ammonia is not high, activity of such catalysts is poor, lost efficacy easily, another kind of is nickel-base catalyst, working temperature can reach about 950 ℃, so the rate of decomposition of ammonia had raising, and the used catalyzer of the present invention is the high temperature modification nickel-base catalyst, temperature of reaction is 700～900 ℃, temperature of reaction is bigger to the influence of ammon residue amount, and whether residual ammonia at high temperature corrodes WU groove material in the hydrogen, is the key that can preparing hydrogen by ammonia decomposition be used for float glass.

In the decomposed ammonia except residual ammonia, major impurity is a moisture, this is by bringing in the raw materials ammonia, its water content of different liquefied ammonia is very big, thereby the gas mixture dew point after decomposing also has very big difference, also has the oxygen of trace sometimes, and this is by due to the dissolved oxygen in the liquefied ammonia, when equipment or pipeline have slight seepage, also can bring oxygen into because of air infiltrates.

For float glass, above-mentioned impurity must be removed, especially ammonia, moisture and oxygen, and floatation glass production line has extremely strict restriction to impurity, and the present invention is the requirement of satisfying the used protection gas of floatation glass production line by adsorption cleaning.

Liquefied ammonia is through the high pure hydrogen nitrogen mixed gas of apparatus of the present invention gained; wherein foreign matter content ammonia is that 01～20PPm, oxygen are dew point≤-50 ℃ of 01～20PPm, water; replace the hydrogen of water electrolysis to mix with the nitrogen that sky divides with this, the WU groove of sending at last in the float glass is made protection gas with making system stable operation again.

The present invention decomposes system high pure hydrogen nitrogen mixed gas device with liquefied ammonia, by ammonia destruction furnace, the shell and tube high-temperature heat-exchanging, cleaner three parts are formed, three parts are by pipe connection, the shell of shell and tube high-temperature heat-exchanging adopts the corrugated tube with temperature compensation, solved generally with floating head type or the compensation complex structure of Ω tubulation, equipment is huge, the problem of heat exchange weak effect, in cleaner, the used sorbent material of the present invention is made up of molecular sieve and the double-deck absorption of silica gel, the reverse adsorption layer that passes through of nitrogen that resurgent gases is divided with sky, the type of heating of cleaner internal heating element is to adopt convection current to give heat and direct heat conduction and radiation to combine, and can avoid molecular sieve to damage because of overheated like this, non-uniform temperature, resurgent gases consumption is big, the shortcoming that regeneration is difficult for.

Use apparatus of the present invention, can make device under the regeneration situation that gas consumption is few, power consumption is little, guarantee absorption property, guarantee that the foreign matter content in the hydrogen nitrogen mixed gas can satisfy the needs of float glass.

Below in conjunction with description and the description of the drawings thereof to implementing an embodiment of the present utility model.

Fig. 1 is the diagrammatic cross-section that ammonia decomposes system high pure hydrogen nitrogen mixed gas device.

Fig. 2 is the diagrammatic cross-section of shell and tube high-temperature heat-exchanging parts.

Fig. 3 is that ammonia decomposes diagrammatic cross-section.

Fig. 4 is the diagrammatic cross-section of cleaner parts.

As shown in Figure 1, the ammonia shown in the present embodiment enters this device from ammonia inlet pipe (1), and high pure hydrogen nitrogen mixed gas leaves this device from product pipe (13).

As Fig. 2, shown in Figure 3, the The Nomenclature Composition and Structure of Complexes of ammonia destruction furnace shown in the present embodiment and shell and tube high-temperature heat-exchanging parts is as follows.

Ammonia inlet pipe 1, hydrogen nitrogen mixed gas outlet pipe 2, high-temperature heat-exchanging shell 3, tubulation 4, end socket 5, ammonia outlet pipe 6, hydrogen nitrogen mixed gas inlet pipe 7, ammonia destruction furnace 14, the outer insulation 15 of shell and tube high-temperature heat-exchanging, ammonia destruction furnace is incubated 16 outward.

From the next ammonia of liquefied ammonia vapo(u)rization system, enter the tubulation 4 of shell and tube high-temperature heat-exchanging through ammonia inlet pipe 1, leave high-temperature heat-exchanging through giving heat from ammonia outlet pipe 6, enter ammonia destruction furnace 14 through the ammonia that gives heat, liquefied ammonia is after 700～900 ℃ of catalytic decomposition, the hydrogen nitrogen mixed gas that generates is got back to the hydrogen nitrogen mixed gas inlet pipe 7 of shell and tube high-temperature heat-exchanging, pass through high-temperature heat-exchanging between pipe, carry out heat exchange with the interior ammonia of pipe like this, hydrogen nitrogen mixed gas leaves high-temperature heat-exchanging from outlet pipe 2 afterwards, enters the adsorption cleaning device then.

As shown in Figure 4; hydrogen nitrogen mixed gas through heat exchange; enter cleaner by adsorption cleaning device inlet 8, the absorption through sorbent material 10 becomes qualified product gas; leave cleaner from product gas outlet pipe 13; the hydrogen nitrogen mixed gas that obtains, wherein foreign matter content ammonia is that 01～20PPm, oxygen are dew point≤-50 ℃ of 01～20PPm, water, replaces the hydrogen of water electrolysis with this; after the nitrogen that divides with sky mixed again, the WU groove that enters the float glass industrial production line was made protection gas and is used.

A card 11 is arranged with the cleaner separated into two parts in the cleaner, put sorbent material 10 at an upper portion thereof, described heating unit 9 is extended to through adsorption layer by the cleaner top always and gives hot cell 12 under the card 11.

During regeneration, the nitrogen that resurgent gases is divided with sky, enter cleaner from product gas outlet pipe 13, through giving hot cell 12, give heat by heating unit 9 by convection current, make its desorb by card 11 is reverse subsequently through sorbent material 10, resurgent gases enters the mouth from the adsorption cleaning device and 8 leaves cleaner, cuts down a leakage and switching polluted product gas in the time of so can be because of regeneration.

The present invention is the energy consumption that has reduced hydrogen manufacturing, and liquefied ammonia hydrogen manufacturing energy consumption only is 60% of a water electrolysis hydrogen producing, and is energy-conservation 40%, as compare the every Nm of water electrolysis hydrogen producing with electric weight ³Hydrogen power consumption 635 degree, the every Nm of preparing hydrogen by ammonia decomposition ³Power consumption 361 degree are to per hour needing 90Nm ³The float glass factory of hydrogen, can economize on electricity 2 * 10 the whole year ⁶Degree.

The present invention has reduced the investment of hydrogen generator station, to per hour needing 90Nm ³The float glass factory of hydrogen, the gross investment of water electrolysis hydrogen producing station equipment is 2,090,000, changes preparing hydrogen by ammonia decomposition into and only needs 820,000 yuan, joint props up 1,270,000 yuan.

Operating maintenance personnel of the present invention reduce, and the operator of preparing hydrogen by ammonia decomposition have only half of water electrolysis hydrogen producing.

Apparatus of the present invention, purity of product gas is constant, and the resurgent gases energy consumption is little, and resurgent gases is few, the long service life of sorbent material heating unit.

Apparatus of the present invention technology is simple, and is easy to operate, and equipment is reliable to be started soon, therefore can guarantee at a cold repair phase (in 3～4 years) hydrogen supply steady in a long-term.By the hydrogen nitrogen mixed gas that apparatus of the present invention produced; the gas purity height; wherein foreign matter content ammonia is that 01～20PPm, oxygen are dew point≤-50 ℃ of 01～20PPm, water; improved the reliability of float glass industry WU groove, made its not only economy but also continuous qualified production float glass with protection gas.

Claims

1, a kind of ammonia decomposes system high pure hydrogen nitrogen mixed gas device, form by ammonia destruction furnace, shell and tube high-temperature heat-exchanging, cleaner three parts, it is characterized in that: described shell and tube high-temperature heat-exchanging shell (3) adopts the corrugated tube with temperature compensation, sorbent material in the cleaner (10) is made up of molecular sieve and the double-deck absorption of silica gel, adsorbed gas and resurgent gases can have heating unit (9) in the reverse cleaner by adsorption layer, and ammonia destruction furnace, shell and tube high-temperature heat-exchanging, cleaner three parts are by pipe connection.

2, decompose system high pure hydrogen nitrogen mixed gas device according to the described ammonia of claim 1, it is characterized in that: a card (11) is arranged in the cleaner the cleaner separated into two parts, put sorbent material (10) at an upper portion thereof, described heating unit (9) is extended to through adsorption layer by the cleaner top always and gives hot cell (12) under the card (11).