阅读说明：本技术 一种用于常压法生产硝酸的氨氧化炉及其工艺方法 (Ammonia oxidation furnace for producing nitric acid by normal pressure method and process method thereof ) 是由 谢强 陈红飚 桂州 于 2020-08-04 设计创作，主要内容包括：本发明涉及一种用于常压法生产硝酸的氨氧化炉及其工艺方法,燃烧反应部,在常压环境下将反应系统中的铂金层加热至氨气和氧气所需的反应温度；铂金层作为媒介,氨气和氧气能够在反应温度下生成氮氧化物,产生热流；热量回收部,用于回收燃烧反应部产生的热量；热量回收部包括至少两个位于第二空间内的不同高度的沿第二空间的轴向安装的盘管组,至少两个盘管组彼此并联于第一进口汇管和第一出口汇管,第一进口汇管相对固定连接有至少两个节流孔径不同的节流孔接头,至少两个节流孔接头能够按照使得至少两个盘管组内的水量不同的方式分别连接至各自对应的盘管组,以使得盘管组能够根据第二空间内的热量差异来吸收热量。(The invention relates to an ammonia oxidation furnace for producing nitric acid by a normal pressure method and a process method thereof.A combustion reaction part heats a platinum layer in a reaction system to a reaction temperature required by ammonia and oxygen in a normal pressure environment; the platinum layer is used as a medium, and ammonia gas and oxygen can generate nitrogen oxide at the reaction temperature to generate heat flow; a heat recovery part for recovering heat generated from the combustion reaction part; the heat recovery part comprises at least two coil groups which are positioned in the second space and are installed along the axial direction of the second space at different heights, the at least two coil groups are connected in parallel with the first inlet manifold and the first outlet manifold, the first inlet manifold is fixedly connected with at least two orifice joints with different orifice diameters, the at least two orifice joints can be respectively connected to the corresponding coil groups in a mode of enabling the water amount in the at least two coil groups to be different, and therefore the coil groups can absorb heat according to the heat difference in the second space.)

1. An ammonia oxidation furnace for producing nitric acid by a normal pressure method, wherein a first space required by a combustion reaction part and a second space required by a heat recovery part are defined in a hearth of the furnace, and heat flow generated by the combustion reaction part can be transferred from the first space to the second space; wherein the content of the first and second substances,

the combustion reaction part heats the platinum layer (19) in the reaction system to the reaction temperature required by ammonia gas and oxygen in the normal pressure environment; the platinum layer (19) is used as a medium, and ammonia gas and oxygen can generate nitrogen oxide at the reaction temperature to generate heat flow;

the heat recovery part is used for recovering the heat generated by the combustion reaction part;

it is characterized in that the preparation method is characterized in that,

the heat recovery section comprising at least two coil groups (9) mounted in the second space at different heights in the axial direction of the second space, the at least two coil groups (9) being connected in parallel to each other between a first inlet header (34) and a first outlet header (6),

at least two orifice joints with different orifice diameters are fixedly connected with the first inlet collecting pipe (34) relatively, and the at least two orifice joints can be respectively connected to the corresponding coil groups (9) in a mode that the water amount in the at least two coil groups (9) is different, so that the coil groups (9) can absorb heat according to the heat difference in the second space.

2. The ammoxidation furnace according to claim 1 wherein the orifice joint has a sealing plate (3404a) at the end extending into the first inlet header (34), said sealing plate (3404a) having small filtration holes (3404b) therein for allowing water to flow radially along the first inlet header (34) to the restricted flow holes (3404c), said small filtration holes (3404b) being open in a manner to restrict the entry of solid matter capable of blocking the restricted flow holes (3404c) into the orifice joint.

3. Ammoxidation furnace according to claim 1 or 2, characterized in that each layer of coil groups (9) is a horizontal spiral coil wound in an equidistant spiral, the pitch between adjacent coil groups (9) being different.

4. Ammonia oxidation furnace according to claim 3, characterized in that said coil groups (9) are confined in said second space by an outer protective cylinder (10), said outer protective cylinder (10) being able to direct said heat flow to a heat exchange area where said coil groups (9) are located.

5. Ammonia oxidation furnace according to claim 1 or 4, characterized in that at least two water wall tube banks (11) are circumferentially held in the second space to the furnace wall by means of an inner protective shell (12), the water wall tube banks (11) being capable of absorbing heat generated by thermal radiation of the heat flow, so that the furnace wall is cooled down in the event that water vapour is by-produced by the water wall tube banks (11).

6. Ammonia oxidation furnace according to claim 5, characterized in that the high temperature gases after reaction through the platinum layer (19) are distributed substantially uniformly to the coil assembly (9) by means of a honeycomb ceramic ring support plate (13) arranged axially along the furnace and able to distribute the platinum layer (19) in a radial direction substantially coinciding with the radial direction of the furnace.

7. The ammoxidation furnace according to claim 1, wherein said combustion reaction portion comprises a motor assembly (30), an ignition tube (23), an ignition gun (21), a hydrogen gas inlet tube (27) and a platinum layer (19);

wherein the motor component (30) is used for driving the ignition tube (23) to rotate so that the flame of the ignition tube can approximately uniformly heat the platinum layer (19) to reach the temperature of the chemical reaction required by ammonia and oxygen;

the ignition gun (21) ignites hydrogen in a hydrogen inlet pipe (27), so that a jet combustion port on a horizontal transverse pipe of the ignition pipe (23) can jet out the flame.

8. The ammoxidation furnace according to claim 7, wherein in the case where the temperature of said chemical reaction is stable, the hydrogen inlet pipe (27) is turned off and the power supply to the speed reducer motor assembly (30) is turned off, and the squib (23) is stopped.

9. A process method for producing nitric acid by a normal pressure method, which is characterized in that,

s1: the motor assembly (30) drives the ignition tube (23) to rotate in the first space, and the ignition gun (21) ignites hydrogen in the hydrogen inlet tube (27), so that a jet combustion port on a horizontal tube of the ignition tube (23) can spray flame, and a platinum layer (19) is heated to a chemical reaction temperature required by ammonia and oxygen;

s2: when the heating temperature of the platinum layer (19) reaches the reaction temperature of the mixed gas of ammonia and air, the mixed gas of ammonia and air is fed from a gas inlet pipe (31), and the mixed gas is subjected to chemical reaction on the platinum layer (19) to generate nitrogen oxide;

s3: the reacted heat flow passes through the honeycomb ceramic ring supporting plate (13) downwards, so that the heat flow is uniformly distributed again and passes through the second spaces of the at least two coil groups (9) downwards in sequence, and the heat flow is used for exchanging heat with media in the coil groups (9); wherein the at least two coil groups (9) are connected in parallel with each other to a first inlet header (34) and a first outlet header (6), the first inlet header (34) is relatively fixedly connected with at least two orifice joints with different orifice diameters, and the at least two orifice joints can be respectively connected to the respective corresponding coil groups (9) in a manner that the water amount in the at least two coil groups (9) is different, so that the coil groups (9) can absorb heat according to the heat difference in the second space.

10. The process according to claim 9, characterized in that in the case of a stable temperature of the chemical reaction, the hydrogen inlet pipe (27) is shut off and the reducer motor assembly (30) is powered off, the squib (23) being deactivated.

Technical Field

The invention relates to the technical field of nitric acid production equipment, in particular to an ammonia oxidation furnace for producing nitric acid by a normal pressure method and a process method thereof.

Background

The ammonia oxidation furnace is a device for generating nitride by the catalytic reaction of ammonia gas and oxygen. According to different production pressures, the production of nitric acid by an ammonia oxidation furnace can be divided into a normal pressure method, a medium pressure method and a high pressure method. The platinum net is a medium for the ammonia gas and the oxygen gas of the ammonia oxidation furnace to fully react. The consumption of platinum increases with the increase in the use pressure and temperature, and the ammoxidation conversion rate decreases. Thus, the production of nitric acid by the atmospheric process is gradually replacing the medium and high pressure processes. At present, the maximum production capacity of the ammonia oxidation furnace for producing nitric acid by the normal pressure method in China is 5 ten thousand tons per set per year, the structure is that an upper frame type reactor and a lower tube type heat exchanger are added, a refractory material is lined in the upper frame type reactor, and the ammonia oxidation furnace with the structure has the defects of high ammonia consumption, high platinum catalyst consumption, high energy consumption, low heat recovery rate, short service life, small device productivity and the like.

For example, the ammonia oxidation furnace disclosed in chinese patent publication No. CN204897407U is characterized by comprising an air inlet, an oxidation furnace main body, and an air outlet, wherein the air inlet is located above the oxidation furnace main body, the air outlet is located below the oxidation furnace main body, the oxidation furnace main body comprises a water wall tube, a heat exchange tube, a baffle, a packing wire mesh, and a sealing cylinder, the baffle is located at the lower edge of the bottommost heat exchange tube, a gap between the heat exchange tube and the water wall surrounds a circle, and the gap between the baffle and the heat exchange tube is not more than 10 mm; the filling wire mesh is a Cr20Ni80 alloy wire mesh, and the filling wire mesh is used for filling gaps between the water wall tube and the heat exchange tube and gaps between the heat exchange tube and the sealing cylinder. The silk screen is filled between the expansion joints, so that the problem that the process gas escapes through the expansion joints is effectively solved, the heat recovery efficiency of the ammonia oxidation furnace is improved, the temperature of the process gas at the outlet of the oxidation furnace is reduced, and the process conditions of the subsequent working procedures are stabilized.

Furthermore, on the one hand, due to the differences in understanding to the person skilled in the art; on the other hand, since the inventor has studied a lot of documents and patents when making the present invention, but the space is not limited to the details and contents listed in the above, however, the present invention is by no means free of the features of the prior art, but the present invention has been provided with all the features of the prior art, and the applicant reserves the right to increase the related prior art in the background.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides an ammonia oxidation furnace for producing nitric acid by a normal pressure method, which is characterized in that a first space required by a combustion reaction part and a second space required by a heat recovery part are defined in a hearth, and heat flow generated by the combustion reaction part can be transferred from the first space to the second space; the combustion reaction part heats the platinum layer in the reaction system to a reaction temperature required by ammonia gas and oxygen in a normal pressure environment; the platinum layer is used as a medium, and ammonia gas and oxygen can generate nitrogen oxide at the reaction temperature to generate heat flow; the heat recovery part is used for recovering the heat generated by the combustion reaction part; the heat recovery part comprises at least two coil groups which are positioned in the second space and are arranged at different heights along the axial direction of the second space, the at least two coil groups are connected in parallel with a first inlet header and a first outlet header, the first inlet header is relatively and fixedly connected with at least two orifice joints with different orifice diameters, and the at least two orifice joints can be respectively connected to the corresponding coil groups in a mode of enabling the water amount in the at least two coil groups to be different, so that the coil groups can absorb heat according to the heat difference in the second space. According to different installation positions of the coils in the ammonia oxidation furnace, the high temperature of the coils is different, the coils in each layer are grouped, the installation heights are different, the grouping numbers of the coils are different, and the absorbed heat is different.

In accordance with a preferred embodiment, the orifice fitting has a sealing plate at an end thereof extending into the first inlet header, the sealing plate having filter apertures therein to enable flow of water radially along the first inlet header to the metering orifice, the filter apertures being open to restrict ingress of solid matter into the orifice fitting which could block the metering orifice.

According to a preferred embodiment, each layer of coil groups is a horizontal spiral coil wound in an equidistant spiral, the pitch of the adjacent coil groups being different.

According to a preferred embodiment, the coil group is delimited in the second space by an outer protective cylinder able to direct the heat flow to the heat exchange area where the coil group is located.

According to a preferred embodiment, at least two water wall tube banks are circumferentially held in the second space to the furnace wall by means of an inner protective shell, said water wall tube banks being capable of absorbing heat from the thermal radiation of the heat flow, so that the furnace wall is cooled down while the water wall tube banks are capable of producing steam as a by-product.

According to a preferred embodiment, the high-temperature gas reacted by the platinum layer is distributed substantially uniformly to the coil groups by a honeycomb ceramic ring support plate arranged axially along the ammoxidation furnace and capable of substantially conforming the radial direction of the platinum layer to the radial direction of the ammoxidation furnace.

According to a preferred embodiment, the combustion reaction part comprises a motor assembly, an ignition tube, an ignition gun, a hydrogen inlet tube and a platinum layer; the motor assembly is used for driving the ignition tube to rotate so that the flame of the ignition tube can approximately uniformly heat the platinum layer to reach the temperature of the chemical reaction required by ammonia and oxygen; the igniter ignites hydrogen in the hydrogen inlet pipe, so that the flame can be sprayed out from the spraying combustion port on the horizontal transverse pipe of the igniter.

According to a preferred embodiment, in the case of stable temperature of the chemical reaction, the hydrogen inlet pipe is closed and the reducer motor assembly power supply is turned off, and the igniter stops working.

According to a preferred embodiment, the present invention provides a process for producing nitric acid under atmospheric pressure, wherein S1: the motor component drives the ignition tube to rotate in the first space, and the ignition gun ignites hydrogen in the hydrogen inlet tube, so that a jet combustion port on a horizontal transverse tube of the ignition tube can spray flame, and a platinum layer is heated to a chemical reaction temperature required by ammonia and oxygen;

s2: under the condition that the heating temperature of the platinum layer reaches the reaction temperature of the mixed gas of ammonia and air, the mixed gas of ammonia and air is fed from a gas inlet pipe, and the mixed gas is subjected to chemical reaction on the platinum layer to generate nitrogen oxide;

s3: the reacted heat flow passes through the honeycomb ceramic ring supporting plate downwards, so that the heat flow is uniformly distributed again and passes through the second spaces of the at least two coil groups downwards in sequence, and the heat flow is used for exchanging heat with media in the coil groups; the at least two coil sets are connected in parallel with each other to a first inlet header and a first outlet header, the first inlet header is relatively and fixedly connected with at least two orifice joints with different orifice diameters, and the at least two orifice joints can be respectively connected to the corresponding coil sets in a mode that the water amount in the at least two coil sets is different, so that the coil sets can absorb heat according to the heat difference in the second space.

According to a preferred embodiment, in the method, in the case that the temperature of the chemical reaction is stable, the hydrogen inlet pipe is closed and the power supply of the reducer motor assembly is turned off, and the igniter pipe stops working.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a front view of the tripod of the present invention;

FIG. 3 is a top plan view of the tripod of FIG. 2 in accordance with the present invention;

FIG. 4 is a schematic structural view of a 17-layer coil assembly according to the present invention;

FIG. 5 is a top plan view of the first tier of the 17-tier coil assembly of the present invention;

FIG. 6 is a schematic diagram of the construction of the outlet header of the coil assembly of the present invention;

FIG. 7 is a schematic view of the coil outlet and service coupling of the outlet header of the coil assembly of FIG. 6 in accordance with the present invention;

FIG. 8 is a schematic view of the coil outlet lead-out and service coupling of the outlet header of the coil assembly of FIG. 6 in accordance with the present invention;

FIG. 9 is a schematic illustration of the construction of the drain fitting of the outlet header of the coil assembly of FIG. 6 in accordance with the present invention;

FIG. 10 is a schematic view of the inlet header of the coil assembly of the present invention;

FIG. 11 is a schematic view of the connection of the coil inlet outlet orifice fitting of the inlet header of the coil assembly of FIG. 10 in accordance with the present invention;

FIG. 12 is a schematic view of the connection of the coil inlet outlet orifice fitting of the inlet header of the coil assembly of FIG. 10 in accordance with the present invention;

FIG. 13 is a schematic view of the drain fitting of the inlet header of the coil assembly of FIG. 10 in accordance with the present invention;

FIG. 14 is a schematic view of the coil assembly inlet outlet orifice fitting of FIG. 10 in accordance with the present invention;

FIG. 15 is a schematic diagram of the construction of a waterwall tube bank of the present invention;

FIG. 16 is a schematic illustration of an expanded arrangement of the waterwall tubes of FIG. 15 in accordance with the present invention;

FIG. 17 is a schematic view of the configuration of the waterwall tube inlet headers of the present invention;

FIG. 18 is a schematic illustration of the connection of the inlet outlet orifice fitting of the waterwall tube inlet header of FIG. 17 in accordance with the present invention;

FIG. 19 is a schematic illustration of the drain fitting of the waterwall tube inlet header of FIG. 17 in accordance with the present invention;

FIG. 20 is a schematic illustration of the configuration of the waterwall tube outlet headers of the present invention;

FIG. 21 is a schematic structural view of a honeycomb ceramic ring support plate according to the present invention;

FIG. 22 is a schematic view of a catalyst support frame according to the present invention;

FIG. 23 is a schematic structural view of an upper stage gas distributor according to the present invention;

fig. 24 is a schematic view of the structure of the squib of the system of the present invention;

fig. 25 is a schematic view showing the distribution structure of the injection burner ports of the squib of the system of fig. 24 according to the present invention.

List of reference numerals

1: gas outlet pipe 6004: service pipe joint

2: skirt support structure 6005: outlet guide pipe

3: lower section casing 6006: service pipe joint

6: first outlet header 6007: condensate draining connecting pipe

8: tripod 3403: second arc tube

9: coil tube section 3404: first orifice fitting

10: outer protective canister 3405: second orifice fitting

11: water wall tube bank 3406: water inlet connecting pipe

12: inner protective canister 3407: liquid-discharging connecting pipe

13: honeycomb porcelain ring support plate 25: supporting tube

15: lower shell large flange 27: hydrogen inlet pipe

16: temperature measuring device 29: speed reduction rack

18: catalyst support frame 30: speed reducer motor assembly

19: platinum layer 31: gas inlet pipe

20: platinum wire mesh pressing ring 32: second outlet header

21: ignition gun 33 of ammoxidation furnace: second inlet manifold

22: upper-stage housing 34: first inlet manifold

23: the ignition tube 6001: elliptical seal head

24: three layers of gas distribution plates 6002: first arc tube

6003: outlet lead 3404 a: sealing plate

3403 b: small filter hole 3404c orifice

Detailed Description

This is described in detail below with reference to fig. 1-25.