CN85103285A

CN85103285A - Use the series connection vapor superheater to carry out the steam reforming of hydrocarbon

Info

Publication number: CN85103285A
Application number: CN198585103285A
Authority: CN
Inventors: 罗伯特·姆·欧斯门
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1985-04-30
Filing date: 1985-04-30
Publication date: 1986-10-29

Abstract

With reference to Fig. 1, (a) hydrocarbon gas charging (6) transforms with part at high temperature with direct flame heating and hot burning gas indirect heating that the one-stage converter (10) of convection zone (4) recovery waste heat is housed; (b) part converted feed (58) becomes two sections to transform vent gas (62) in two sections convertors (60) lining with oxygenous with steam reforming; It is improved one's methods and uses in the first steam superheating district (80) to above-mentioned two sections conversion vent gas (76) the indirect heating high-pressure saturated steams of small part (82) formation first step superheated vapour (84) for (i); (ii) in second overheated zone (25), use to the above-mentioned one section above-mentioned first step superheated vapour formation of the conversion hot gas indirect heating second stage superheated vapour (36) of small part.

Description

Use the series connection vapor superheater to carry out the steam reforming of hydrocarbon

The invention relates to improving one's methods of steam reforming hydro carbons gas feed, more specifically say so about utilizing the series connection vapor superheater to improve the steam conversion process of heat accumulation.

In general, the preparation of ammonia comprises from nitrogenous source (being generally air) and hydrogen source (generally can be coal, petroleum fractions or Sweet natural gas) preparation ammonia synthesis gas.For example, from the lightweight hydrocarbon feed, when promptly from the Sweet natural gas to the petroleum naphtha, preparing ammonia synthesis gas, at first remove gas pollutant hydrocarbon feed gases is purified, for example become hydrogen sulfide on the zinc oxide adsorption medium, to be adsorbed and from raw material, remove desulfuration (sulphur in the unstripped gas can make downstream catalyst poison) by the sulphur compound shortening.The steam reforming of pollution-free gas subsequently will provide from hydrocarbon gas and prepare the needed most of hydrogen of synthetic ammonia.Conversion is finished by two-stage process, wherein the mixture of the unstripped gas of steam and purification is at first transformed on the catalyzer in one section convertor, then the gas that the treating part transforms in two sections convertors introduces in two sections convertors air to provide ammonia synthesis required nitrogen amount.Generated reforming gas in two sections convertors, it has bigger hydrogen and more a spot of hydrocarbon.The unstripped gas converting reaction process resolves into methane, carbonic acid gas and carbon monoxide from hydrocarbon:

And finish i.e. conversion of methane by desired heat absorption with the conversion of these products:

And thermopositive reaction by following:

In one or more shift converters, change the carbon monoxide in the reforming gas into carbonic acid gas and other hydrogen, remove carbonic acid gas with washing method.Crude synthesis gas is further handled to remove carbonic acid gas and the carbon monoxide in the hydrogen-rich gas by methanation, generate ammonia synthesis gas then, approximately contain three parts of hydrogen and a nitrogen in the synthetic gas, be that the stoichiometric ratio of hydrogen and nitrogen is 3: 1 in the ammonia, also has a spot of stable gas in addition, as methane, argon and helium.Gas is by metallic iron (being generally magnetite) supported catalyst surface and then make ammonia synthesis gas transform ammonification, and can use other metal oxide to make promotor.Ammonia is synthetic by following thermopositive reaction:

Common conversion ammonia plant design receives the available used heat of portion back and forth by producing high-pressure saturated steam, this used heat is to reduce to the temperature (typically using inlet temperature is 316～399 ℃) that is suitable for the high temperature shift furnace operating from two sections convertor vent gas (typical temperature is 1600～1900, promptly is about 871～1004 ℃) to be produced.Because the saturated-steam temperature in the pressure range of sophisticated steam turbine technology is not more than 343 ℃,, it seems that from the viewpoint of the second law of thermodynamics this is undesirable so this temperature that has formed two sections convertor vent gas heats is fallen.The more important thing is, this means to the adaptive strict restriction of balance of steam, because used heat only is used to produce saturation steam.

In the United States Patent (USP) 3,441,393 of Pullman, use placed in-line two-stage saturated steam generator to reclaim the heat of two sections convertor vent gas.

In the disclosed various patents of Imperial Chemical Industries (ICI), two sections convertor vent gas at first are used for producing saturation steam at first step vapour generator, and then be used for producing superheated vapour from the steam that vapor superheater comes, vapor superheater also reclaims heat from the ammonia synthesis reactor vent gas.At last, other saturation steams are that two sections convertor vent gas sending in the vapour generator of the second stage before the conversion produce.

United States Patent (USP) 4213954 and 4264567 has illustrated these systems.The United States Patent (USP) 4367206 described explained hereafter methyl alcohol and the ammonia of Imperial Chemical Industries (ICI), wherein heat is to use the way of superheated vapour to reclaim from the vent gas of an ammonia synthesis reactor catalytic section, and superheated vapour is discharged the further overheated of gases by indirect heat exchange with two sections convertors again.But, this technology is difficult to use with more novel ammonia synthesis reactor, because needing a large amount of custom catalystses to improve energy efficiency and be preferably under the lower temperature, operate these more novel ammonia synthesis reactors, also be not easy in addition to use, operate because these catalyzer also are preferably under the lower temperature with novel ammonia synthesis catalyst.In addition, this technology also needs to use expensive High Pressure Shell, because, if adopt the energy-saving type high pressure steam generator, two kinds of fluidic pressure that carry out heat exchange so all will be above 1000 pounds/inch, and promptly (steam side is 1000～2200 pounds/inch to 68.95 crust (gauge pressure), promptly 68.95～151.69 cling to, reactor vent gas side is 6900～41,370 kPas, i.e. 69～413.7 crust).

The United States Patent (USP) 3442613 of Braun has also illustrated the system that produces saturation steam when two sections convertor vent gas reclaim heat.Another of this respect piece patent is the United States Patent (USP) 3947551 of Benfield.

The steam reforming technology of hydrocarbon gas charging comprises: (a) the appropriate hydrocarbon gas charging transforms by carrying out part with the mode of the hot burning gas indirect heat exchange of the general converter of direct flame heating under the intensification condition, general converter is equipped with convection zone to reclaim the waste heat in the said burning gas, feeding gas that part transforms is further transformed in the oxygen-containing gas of two sections convertors and steam generate two sections convertor vent gas; It is improved one's methods and comprises by following steps are said and transform the combustion prod and reclaim used heat from two sections convertor vent gas and said one section, (ⅰ) pass through indirect heat exchange heating high-pressure saturation steam to form first step flow of superheated steam with the said two sections convertor vent gas of at least a portion, (ⅱ) further heat said first step superheated vapour to form second stage flow of superheated steam with the said one section convertor hot combustion gas of at least a portion by indirect heat exchange in second stage steam superheating district in first step steam superheating district.

Owing to more and more pay attention to the ammonia plant design of research less energy-consumption, so more and more Duo technology used heat is recovered by the method that produces steam, other conservation measures then focuses on the minimizing steam consumption.These net effects trend towards making the new and effective clean vapour generator that is designed to.But, if the application of the steam that is gone out is restricted, so at first can not reach purpose of energy saving, perhaps must deliver to power plant to excessive steam and carry out inefficient steam turbine power generation.Steam turbine power generation needs very high investment, if with coal, nuclear energy or water generating have not just more had magnetism at a low price.The present invention will make production of steam reduce to minimum when keeping high energy efficiency.

Fig. 1 is the synoptic diagram of an embodiment of method of the present invention.

Fig. 2 is as the high pressure steam of embodiment 1 described complete hydrocarbon steam conversion process and the synoptic diagram of heat recovery system.

Fig. 3 is the synoptic diagram of part flow process in the method shown in Figure 1, shows the method that controlledly produces superheated vapour with two sections convertor vent gas used heat.

Fig. 4 is the synoptic diagram of part flow process in the method shown in Figure 1, and this is the another kind of method that controlledly produces superheated vapour with two sections convertor vent gas used heat.

Fig. 5 is the synoptic diagram of part flow process in the method shown in Figure 1, and this is another method that controlledly produces superheated vapour with two sections convertor vent gas used heat.

With reference to Fig. 1, generally has convection zone 4 and not shown as can be seen by one section conversion radiation section 18(well heater of burner heating with numeral 10 one-stage converters that mark, for example can be contained in the bottom of radiation section), as diagram supplied burner fuel gas 14 and oxidizing gas (as combustion air) 16.The hot flue gases of discharging by the radiation section convection zone 4 of flowing through, process steam over-heat-exchanger 21 is produced with air (can contain steam and air) heat exchanger 26, power steam over-heat-exchanger 25, feeding gas heat exchanger 24, feedwater preheater 22, is discharged by chimney 2 then.So one section convertor 10 is to come direct-fired with wherein the fuel gas 14 and the burning of oxic gas 16.As can be seen, the flow direction that hot burning gas passes through in general convertor 10 is not strict, and one section convertor 10 can adopt conventional design, narrates as United States Patent (USP) 4213954, wherein burning gas is passed through downwards from the top of the radiation section of convertor, and convection zone is a lateral arrangement.

Two sections method for transformation need to add four kinds of factory supplies, feeding gas (being used as hydrogen source), steam, oxygen-containing gas and fuel gas to one section convertor respectively.In addition, in order to produce ammonia synthesis gas, generally in two sections conversion processes, add source nitrogen (normally air) with method for transformation.

Charging is to add in the reaction process by pipeline 6, and the feeding gas heat exchanger 24 of flowing through and being positioned at the one-stage converter convection zone, makes feeding gas be preheating to about 750 °F, promptly about 399 ℃.The accessible gas raw material 6 of method of the present invention can have very wide variation range.Described as United States Patent (USP) 3649558, except the coal Pintsch gas, suitable feeding gas comprises coke(oven)gas and refinery gas, and raw materials such as gas (IBG) stream, other feeding gas that suits of those medium heats (intermediate BTU) that produce by conventional gasification process from coal or brown coal also have Sweet natural gas, petroleum naphtha, liquefied petroleum gas (LPG) (LPG), natural gas liquids (LNG) or the like.

Hot feed gas flows out through pipeline 38 from heat exchanger 24, mix with the gas that contains H, under the intensification condition with Hydrobon catalyst commonly used, for example Co-Ni on the available support or Ni-Mo Hydrobon catalyst contact, make that sulphur compound changes into sulphur in the unstripped gas, remove sulphur at desulfurization zone 44 then.

If contain COS in the raw material, available another kind of scheme, promptly except hydrodesulfurizationzone zone 40 and, feeding gas 38 can with the vapor mixing of capacity to supply with the required water of COS hydrolysis reaction.The quantity of steam that adds can have wide variation range, is benchmark with the total feed gas scale of construction of discharging from heat exchanger 24 in pipeline 38, generally contains 2～4%(volume).The COS reaction can be carried out by usual way, uses hydrolyst commonly used, as active alumina.In this reactor,, promptly be transformed into H with containing COS in the feeding gas under the general hydrolysising condition of 20.69～41.37 crust greatly about 149～177 ℃, 2069～4137 kPas ₂S gas.

The gaseous mixture of handling (or from COS hydrolysis) generation from hydrogenating desulfurization can contain H ₂S enters desulfurization zone 44 through pipeline 42, and gas temperature is about 316～399 ℃ usually, and wherein hydrogen sulfide impurities can remove from air-flow with general method, for example available zinc oxide adsorption bed.Be substantially free of the gas [for example contain weight) sulphur compound (in elementary sulfur)] of sulphur impurity less than 0.2ppm(, discharge also and vapor mixing through pipeline 54, this can be by finishing steam through pipeline 12 flow in pipes 54, this steam contains the waste gas that some steam turbine 50 is discharged at least.Usually, both can also can mix with the latter earlier earlier with mixing with desulfurization material gas again after 12 heating of turbine steam waste gas, and then the heating gas mixture, send to then and carry out one section conversion.The quantity of steam scope that adds at this place is generally the carbon in 2.5～5.0 mol steam/molar processed gas charging.Provide subsequently the required water of conversion reaction in the effect of the steam of this adding.Steam/processed gas mixture is added in the pipeline 56 of one section convertor 10,, make unstripped gas carry out part at least and transform, be filled with conversion catalyst in the pipeline 56 by under conversion condition, reacting with unstripped gas.Any a section of conversion catalyst commonly used as nickel, nickel oxide, chromic oxide, molybdenum and composition thereof or the like, all can use, and with the nickel on the calcium aluminate carrier or the nickel on the alumina supporter for the most desirable.Temperature in the pipeline 56 is generally 427～816 ℃, and pressure is generally 2069～6900 kPas ₂Promptly 20.69～69 cling to, total gas hourly space velocities are 5000～15,000 hour in the pipeline 56 ^-1(V/V/hr.), be preferably 6,000～10,000 hour ^-1(V/V/hr.).

Because the result of conversion reaction in the pipeline 56 of general convertor 10, hydrocarbon components (except that methane) all in the feeding gas all transform into CH basically ₄, CO, CO ₂And H ₂; Part original methane component changes into CO, CO similarly ₂And H ₂, temperature of gas mixture generally rises to about 677～802 ℃, generally containing remaining methane content in the gas that part transforms is 5～20%(volume) CH ₄(butt).

Hot combustion gas is sent the width of cloth section of penetrating 18 from the outside of pipeline 56, sends into convection zone 4 again, contacts with 22 at this hot gas and heat exchanger 21,26,25,24, carries out heat exchange to reclaim heat with various air-flows.The technology of available routine selects the accurate number of convection zone heat exchanger and order so that to invest minimum and (perhaps) recovered energy maximum.(for example, one or more above-mentioned heat exchangers can be divided into several independent unit to reach more favourable temperature distribution in convection zone 4).Oiler feed is delivered to dry drum 100 through pipeline 30 again by heat exchanger 22, and steam makes it overheated by

heat exchanger

80 and 25 more then, and (below will be described in more detail), vapor temperature can reach about 482 ℃.(, also can deliver in the dry drum 100 if desired) with another part oiler feed of other mode preheatings.This steam is delivered to turbine 50 actings again, discharges through pipeline 28 from the vapor portion of turbine gas exhaust duct 52, and rest part feeds heat exchanger 21 and reheats to about 649 ℃ so that convection zone 4 inner rooms connect the steam of discharging after the heat exchange, delivers to pipeline 12 then.This reheated steam is mixed with feeding gas after the desulfurization, sends into then in the pipeline 56 of the convertor that is filled with catalyzer in the radiation section 18.

To deliver to one section convertor by pipeline 32 with air from the production that any source easily obtains and carry out preheating in the counter-flow heat exchanger 26, therein, make it heating by indirect heat exchange with one section hot convertor convection gas.(generally being heated to 482～704 ℃ temperature range).Before the heat-processed or in the middle of heat-processed, produce with air and can mix with part turbine exhaust vapour 13.The gaseous mixture one that transforms through pipeline 34 and the part of sending into through pipeline 58 with air (no matter whether with vapor mixing) of Jia Re production two sections convertors 60 that raise track like this.

Regulate with general setting device (not shown) through the air capacity that pipeline 34 is sent into, the air that provides should be the H that is enough in the ammonia synthesis gas with the ratio of feeding gas ₂With N ₂Ratio be about 3: 1, the H that promptly provides ₂With N ₂Ratio be about 2.6: 1～3.2: 1, preferably be about 2.7: 1～3.2: 1.

Two sections convertors 60 can be the adiabatic convertors of conventional design, utilize oxygen wherein to make it further conversion with the heat that part transforms the thermopositive reaction release of raw material under steady state operation condition.Catalyst consumption in the convertor 60 and type also are general, are typically the Ni catalyzer on the alumina supporter.Two sections general temperature outs of using of convertor are about 871～1038 ℃, and pressure is about 2069～6900 kPas of i.e. 20.69～69 crust, and the hourly space velocity of total gas is about 6000 to 10,000 hours ^-1(V/V/hr.).

The remaining CH of butt of convertor expellant gas (general temperature is about 871～1038 ℃, and has about 0.2～2.0%(volume) ₄) extract out by pipeline 62 from two sections convertors 60, deliver to vapour generator 70 then, make the preheating of delivering to producer 70 through pipeline 72 to the water generates saturated high pressure steam at this, and extract out through pipeline 74.The high pressure steam 74 of Chan Shenging is sent to dry drum 100 like this, this also is the heat source (generally being preheating to about 232～343 ℃) of preheating feedwater, (gas flow temperature generally is about 454～816 ℃ and extracts and deliver to vapor superheater 80 out by pipeline 76 and go overheatedly to deliver to steam there from dry drum 100 by pipeline 82 (general temperature is 232～343 ℃ of pressure about 2760～15 the two sections convertor vent gas of part refrigerative that generate, 170 kPas, promptly 27.60～151.70 cling to), to produce superheated vapour.The general temperature of superheated vapour 84(is 260～510 ℃, pressure about 2760～15,170 kPas, promptly 27.60～151.70 cling to) be sent in the over-heat-exchanger 25 of general convertor convection zone 4, produce higher leveled superheated vapour there, the humidity of the superheated vapour of Xing Chenging is general about 316～566 ℃ like this.Refrigerative convertor discharging gas is delivered to high temperature shift (HTS) stove 90 from superheater 80 through pipeline 86, and the CO in this convertor discharging gas becomes CO with usual method with device transform on catalyst bed commonly used ₂With other hydrogen.

Usually, the temperature that shift converter 90 adopts is about 316～482 ℃, and pressure is about 2069～6900 kPas and promptly is about 20.69～69 crust, and the chromium that catalyzer is generally on the carrier helps catalytic iron catalyst.Then, the high-temperature shift converter exit gas is through pipeline 92 extractions and deliver to second stage vapour generator 94, makes feedwater 96 produce saturation steams 98 there, and is back in the drum 100, obtains feedwater 96 from drum.Part refrigerative high-temperature shift converter vent gas also can be after further reclaiming heat, as in another oiler feed preheat exchanger from producer 94() be sent to low temperature shift (LTS) stove 105, or preferably deliver to guard bed 190 earlier.

Guard bed 190 can choose wantonly, preferably be used for handling in low temperature shift converter 105 gas stream upstream 99, so that remove fontanel element and sulphur impurity, thus any catalyzer of and sulfur sensitive plain in the protection low temperature shift converter 105 to fontanel.Guard bed 190 the operational condition and the type of catalyst system therefor are (for example, help catalytic zinc oxide with cupric oxide) all be general, this step is operated under the temperature and pressure condition of low temperature shift converter as described below 105 usually, as removes the guard bed 190 used solids that contain fontanel and sulfur-containing impurities and can contain same catalyzer with 105 li of low temperature shift converters.

In shift converter 105, low temperature shift reaction is to use method and apparatus commonly used to carry out on common catalyzer, to generate more substantial H ₂And CO ₂Usually, the temperature that shift converter is 105 li is about 204～260 ℃, and pressure is 2069～6900 kPas, promptly 20.69～69 clings to, and catalyzer generally is the mixture of zinc oxide and cupric oxide.The discharging gas of low temperature shift converter 105 is cooled in heat recovery area 114 (heat recovery area can comprise one or more heat exchangers), and the low temperature shift converter that is cooled discharging gas 103 is sent to CO after having consumed its calorific value ₂Remove district 110, adopt general method (as CO at this ₂The solvent adsorption of gas) removes CO through pipeline 111 ₂With the essentially no CO that generates ₂Gas add in the common methane conversion district 120 (often comprising one or more heat exchangers) through pipeline 112 and remove unnecessary CO ₂And CO, discharge through (pipeline 124) then.Compression back is delivered to ammonia synthesis and recovery zone 140 as direct charging through pipeline 126 in compressor 130, at this, utilizes common process (promptly on the Fe catalyst bed, temperature is under 316～538 ℃ the condition) to make H ₂/ N ₂Synthetic gas 126 generates ammonia NH ₃Waste gas is discharged with methane in the clear (area) 140 and argon gas impurity through pipeline 142, reclaim product ammonia through pipeline 144.Heat unnecessary in the ammonia synthesis section is removed with heat extraction equipment 152, and heat extraction equipment can comprise heat exchanger, boiler or the like.

CO ₂The operation that removes district 110, methane conversion district 120, compressor 130 and ammonia synthesis district 140 all is conventional, need not to do to illustrate more completely in order to understand method of the present invention fully.And accurate operating parameters of each such processing step and equipment are easy to be understood by the those of ordinary skill of the same industry, and each step can comprise that prior art thinks useful internal recycle logistics and operation steps commonly used.Therefore, CO ₂Remove district 110 and can comprise common CO ₂Absorption and desorption procedure make rich CO in operating process ₂Air-flow 103 with contain CO ₂Solvent or be easy to and CO ₂The soluble compound of reaction is (as K ₂CO ₃) liquid contact, discharge CO ₂With no CO ₂Gas, (general CO among the latter ₂Content is lower than the 0.3%(volume)).Through solvent treatment with desorb CO ₂Gas 111 loops back adsorber then.District's 110 also available common pressure swing adsorption processs remove CO ₂At Kir

In the encyclopedia of chemical technology of-Othmer (the 3rd edition, the 2nd volume, 492-494 page or leaf, 1978) suitable CO commonly used has been discussed ₂Remove the test of system.Equally, the general temperature that methanator 120 uses is about 260～482 ℃, and pressure is about 2069～6900 kPas of i.e. 20.69～69 crust, and the Ni catalyzer on the carrier (as the nickel on alumina supporter) makes any CO and CO remaining in the air-flow 112 ₂Change into methane, consequent discharging gas 124 contains and is less than the i.e. 1,000,000/volume of about 10vppm() CO and CO ₂Total amount, and H ₂And N ₂Mole ratio be about 2.6: 1～3.2: 1.As required, the compression in the zone 130 can be divided into several sections to be carried out, so that methanator discharges the pressure that reaches synthesis reactor after air pressure contracts, this pressure is about 10340～34470 kPas usually, promptly about 103.4～344.7 crust.(if desired, compressor 130 can be installed in 110 upstream, district, and 110 li make gas compression before handling in the district).At last, as required, ammonia synthesis district 140 can comprise general drying plant removing the minor amount of water in the synthetic gas, and can comprise that removing commonly used reclaims the unit and handle the part or all of gas of discharging from ammonia synthesis reactor to reclaim and circulation H ₂To reactor, therefrom remove the stable gas of formation simultaneously, as CH ₄And argon.(if desired, this drying plant commonly used can be contained in before the gas compression district 130 or its intermediate point)

The synthetic gas 126 of improving one's methods and producing of the present invention has H ₂: N ₂Mole ratio be about 3: 1 and promptly be about 2.6: 1-3.2: 1, wherein remaining methane concentration (butt) is less than about 3%(volume), more typical for being less than the 2%(volume), therefore, this synthetic gas is suitable for the direct charging as ammonia synthesis reactor district 140 especially, that is to say that before ammonia synthesis reaction, synthetic gas 126 need not to carry out low temperature purification to remove unnecessary nitrogen and (perhaps) methane after methanator 120.If desired, synthetic gas also can carry out low temperature purification before entering ammonia synthesis reaction zone, for example use United States Patent (USP) 3,442, and 613 disclosed low temperature purification methods, wherein said method are only for referencial use when implementing method of the present invention.

Expressed a kind of method of preferred generation superheated vapour among Fig. 3, promptly reclaim its used heat from two sections convertor vent gas 62, produced superheated vapour, Fig. 1 has expressed its production method.Two sections convertor vent gas 62 are delivered to earlier and are made preheating current 72 produce saturated high pressure steam 74 in the saturated steam generator 74 in the embodiments of figure 3.Two sections convertor vent gas 76 of part refrigerative are discharged from boiler 70 and are delivered in the first step series connection vapor superheater 89 and produce superheated vapour 84, as mentioned above, this steam are delivered in the superheater 25 of convection zone again.In this embodiment, delivering to the high pressure steam that over-heat-exchanger 89 goes is steam 77, it is produced by high-pressure saturated steam 82 in second stage heat exchanger 85, to form further warmed-up steam 81, merge after pipeline 77 is delivered to first step interchanger 89 then with through the reject steam of valve 75 flow ipes 87.The thermal medium of second stage heat exchanger 85 comprises further two sections convertor vent gas 79 that cooled off of discharging from first step over-heat-exchanger 89.So just form needed two sections convertors and discharged air-flow 86, delivered to shift converter or boiler then as mentioned above.In the embodiments of figure 3, the open site may command of the valve 75 of 87 li of bypass ducts is to obtain the needed temperature " T that leaves the superheated vapour 36 of superheater 25 ₁", as mentioned above, superheater 25 is arranged in convection zone 4.Near vapour generator 70 second bypass duct 62b is furnished with variable valve 62a, regulates its open site to obtain needed two sections temperature " T that discharge air-flow 86 that leave the cooling of steam superheating interchanger 85 ^' ₁".These feedback regulation valves 75 and 62a make the metal temperature in the interchanger 89 lower, thus available cheap metal and (or) prolong work-ing life of interchanger.So in Fig. 3, first step steam superheating district comprises placed in-line two superheaters 89 and 85.

Distribute steam and the thermal equilibrium that depends on full factory at the over-heat-exchanger 80 of two sections convertor vent gas and the preferred overheated load between the convection zone superheater 25.

Preferably, the steam superheating amount of in the over-heat-exchanger 80 of two sections convertor vent gas, finishing should be enough to save in the convertor burner hearth convection zone aid burning (promptly, so arrange so that can reach whole overheated loads without aid burning), and don't be fully to reclaim useful convection zone used heat to establishing the convection zone boiler greatly.

With reference to Fig. 4, expressed the embodiment of Fig. 3 at this, wherein, the open site of valve 75 that can regulate 87 li of bypass ducts is to obtain the temperature " T of required air-flow 86 ₃" air-flow is included in the inlet air flow in high temperature shift district 90.Detected temperature " the T that leaves the superheated vapour 36 of convection zone superheater 25 ₂" being used to control the open site of the valve 62a on the by-pass line 62b, this bypass is to be contained in the other inlet amount of controlling two sections convertor vent gas 62 delivering to producer 70 of vapour generator 70.

Refer again to Fig. 5, two sections convertor vent gas 62 are sent to saturated steam generator 70 so that preheating current 72 produce saturated high pressure steam 74.As mentioned above, two sections convertor vent gas 76 of part refrigerative are discharged from boiler 70 and are delivered to vapor superheater 80 and remove to produce superheated vapour 84, then superheated vapour are delivered to convection zone superheater 25.In order to regulate the vapour amount of the saturated high pressure steam 82 of delivering to superheater 80, a bypass 87 to be installed in that heat exchanger 80 is other, and valve 75 is housed, the opening degree of regulated valve reaches the required temperature " T of desired superheated vapour 36 ₄".(superheater 80 can be divided into placed in-line two heat exchangers more arbitrarily certainly, the layout of its steam by-pass and setting device, as shown in Figure 3).This just forms two sections convertors of part refrigerative and discharges air-flow 180, then it is delivered to second stage saturated steam generator 170, to produce the saturated high pressure steam 174 of replenishing from preheating current 172, and the further chilled two sections convertors of formation are discharged air-flow 86, as mentioned above, this air-flow can be sent to shift zone 90.The bypass 176 that valve 175 is housed preferably is contained in second stage boiler 170 sides, delivers to the amount of two sections convertor vent gas of boiler 170 with adjusting.Best, variable valve 175 reaches the desired humidity " T that measures in 86 li in air-flow ₅".

Of the present invention improving one's methods is further described with reference to following embodiment.

Embodiment 1

For the improvement that method more of the present invention reached, following method is studied, and with reference to the simple and easy ammonia factory's high pressure steam shown in Fig. 2 and the graphic extension of heating system, the definition of used term is listed in the table 1 among Fig. 2.

The definition of term among table 1 Fig. 2

Title is explained

One section convertor convection zone of QAUX aid burning stove rate of combustion

The heat of one section convertor convection zone of QBOILF boiler is carried

The heat of two sections convertor dischargings of QBOIL2 gas waste heat boiler 70 is carried

The heat of the whole converter convection zone of QCONV is carried

QECO one-stage converter convection zone economizer (Economizer) (BFW ⁽¹⁾In advance

Hot device 22) heat is carried

The rate of combustion of QMAIN one-stage converter radiation section burner (14+16 burning)

QMISC is used to produce steam and BFW ⁽¹⁾Other used heat of preheating is (from height

Temperature stove (HTS), the discharging gas of low temperature oven (LTS) and ammonia synthesis reactor)

QPRO one-stage converter convection zone production preheating load ⁽²⁾

QRAD is by the radiant heat of one section convertor of catalysing tube 56 absorptions

The inlet 86 of two sections convertor discharge outlets 62 of QSEC and high-temperature shift converter 80 it

Between available whole used heat

The heat of QSHTF one-stage converter convection zone superheater 25 is carried

The heat of two sections convertor dischargings of QSHT gas superheater 80 is carried

Whole 10340 kPas of S1500, the i.e. production (pipeline 36) of/482 ℃ of superheated vapours of 103.4 crust

Annotate: (1) oiler feed

(2) the feeding gas heat exchanger 24, and process steam heat exchanger 21 and production are carried total amount with the heat of air heat exchanger 26.

(among Fig. 2, this term of " blowdown " blowdown is meant for fear of the accumulation of the excess of the micro-non-volatile impurity of bringing boiler along with feedwater into, and the less water of from boiler, removing with conventional way.Aid burning refers to the general auxiliary burner that uses in the one-stage converter convection zone)

In method A, method of the present invention illustrates by the embodiment of Fig. 1, and uses above-mentioned series

connection vapor superheater

80 and 25 to prepare ammonia synthesis gas.In method B, improved the embodiment of Fig. 1, all steam superheatings are to carry out in the convection zone of one-stage converter, the used heat of discharging gas only is used for producing saturation steam (that is to say and do not use vapor superheater 80), in method C, the improvement of Fig. 1 is with two sections all steam of convertor discharging gas waste heat superheater, but does not use convection zone superheater 25, in method D, in one section convertor of method C, be provided with common convection zone boiler.

With reference to table 2, the layout of series connection superheater can be compared with the most frequently used practice among the method B in method A, in method B whole overheated being placed in the converter convection zone is carried out, and only discharges the gas used heat with two sections convertors and produce saturation steam.Heat among the method A between two superheaters of placed in-line superheater adjusting is carried to distribute and is carried [QCONV=185.84 gigajoule/time (GJ/hr.)] so that produce the heat of whole converter convection zone, this heat is carried and have been used from the waste gas that leaves the converter radiation section available all heats (to these embodiment, drop to 160 ℃ of chimney outlet temperatures always), but at convection zone without any need for aid burning.Among the common method B, the handiness of (with having burning of same radiation section convertor and heat among the method A and carrying) the superheater method of not connecting, and in secondary reformer discharging gas waste heat boiler, produce a large amount of excess steams [105.2 gigajoules of QBOIL2 from method A/time (GJ/hr) be raised to 190.5 gigajoules among the method B/time (GJ/hr)].This need more oiler feed, this water improved the pre-heat load of convection zone oiler feed (in contrast to 70.6 gigajoules/time, QECO was 112.3 gigabit ear/times).The steam growing amount that is increased also improved widely whole overheated load (in contrast to 97.1 gigajoules among the method A/time, QSHTF add QSHT2 be 129.4 gigajoules/time).Comprehensive these effects, can see steam production in method B (S1500) increase to 52808 kilograms/time, the convection heat that expends carry the sudden change reach 159.4 gigajoules/time, the efficient of supposing one-stage converter is 90%, so with regard to need 177.1 gigajoules [low heat value (LHV)]/time auxiliary fuel burn (QAUX), this also be equivalent to 4.2 gigajoules (low heat value) (LHV)/metric ton NH ₃(MeTNH ₃).If the steam that increases can not get efficient application, that will cause huge power loss.

Method C and D are opposite with method B situation, and all are overheated all uses two sections convertors discharging gas used heat to carry out (not having the convection zone superheater).In the one-stage converter convection zone, do not produce steam among the method C.Among the method D,, on the basis of method C, added a common boiler in order in convection zone, to produce steam.

In method C, do not have the convection zone boiler, whole steam of generation drop to 153.074 kilograms/time.Because it is overheated that more two sections convertors discharging gas used heat must be used for, the heat that correspondingly can be used for producing steam has just reduced.In method C, the load of economizer has also descended, and this is because less oiler feed needs preheating.Generally speaking, the load of whole convection zone drop to 170 gigajoules/time (not having overheated and less economizer load).Owing to there is not aid burning, in convection zone stack gas, available " nature " heat obtainable heat of final stack temperature of cooling stack gas to 160 ℃ (promptly from) be 1859 gigajoules/time, 15.9 gigajoules/time heat in chimney, lost in the uphill process.If this must be compensated in the other boiler of 90% efficient, needed additional combustion will be 17.7 gigajoules/time, be equivalent to 0.4 gigajoule (low heat value) (LHV)/metric ton NH ₃

If the method D of elephant has installed the convection zone boiler, the discharged steam loss of carrying out whole two sections convertors that taken place when overheated with two sections convertors discharging gas can be compensated in the converter convection zone.Can be at last in method A, make the global energy balance that is equal in the series connection superheater.As can be seen from Table 2, all the load (QCONV) of convection zone is the same with whole steam productions (S1500).In this case, the advantage of the overheated principle of connecting does not lie in the handiness that energy has results or increased steam production, but has simplified the operation scheme of technical process.The compulsory boiler water circulation of common needs system for the convection zone boiler, this need increase the investment of boiler water circulating pump, process cost and reliability.On the contrary, as represented in series connection superheater principle, do not have the convection zone boiler, just only need to use fairly simple natural boiler water circulation system usually like this, this does not just need boiler or recycle pump.

Generally speaking, use

series connection superheater

80 and 25 by method of the present invention, with the operation scheme of general ammonia synthesis factory technics flow process by comparison, substantial advantage is provided, particularly the steam that has limited for use is discharged the design that the lower power intake design and use low depth of potentiality transforms, just have more advantage, wherein, have in two sections convertors discharging gas be higher than the 0.8%(volume) methane (butt).

The energy effect of each overheated scheme of table 2 ⁽¹⁾

Annotate: (1) convertor radiation heating (QMAIN) is identical to all methods with the heat (QRAD) of absorption.Benchmark is the balance of steam value that is used for 1000 tonnes/workaday ammonia factory.

(2) suppose that not needing to shield boiler prevents that convection zone is subjected to photothermal influence the (otherwise QBOILF is not zero, improves and QAUX and S1500 even meeting are further) of auxiliary burner.The load of also supposing economizer must be risen (keeping identical oiler feed preheating temperature) to avoid convection zone thermal conduction concentrated.

(3) if the recovery of the convection zone used heat that has lost must compensate by 90% efficient boiler, just will additionally need 17.7 gigajoules (low heat value)/time fuel, be equivalent to 0.42 gigajoule (low heat value)/metric ton NH ₃(gigajoule=joule * 10 ⁹, the LHV=low heat value)

(4) suppose that 90% convection zone recovery of heat is from aid burning (1 ^*Convertor)

(5) be equivalent to 4.3 kilomegabit ears (low heat value)/metric ton NH ₃

Embodiment 2

For improving one's methods of further confirming that the present invention reached, other following methods are studied, referring again to the definition of term in simple and easy ammonia factory's high pressure steam shown in Figure 2 and heating system schema and the above-mentioned table 1.

Described as example 1, method A represents technology of the present invention.Among the method A, do not carry out steam superheating in the heat recovery area 152 of ammonia synthesis shift zone 140, in method E by improved the method for Fig. 1 at the synthetic district of umformer 140 superheated vapours.Promptly steam superheating interchanger 152 usefulness amminos grow up to be a useful person the discharging gas carry out indirect heat exchange, then, as shown in Figure 1, further overheated in the second stage superheater 25 in the convection zone of one section convertor (QSHTC in the table 3 refers in order to retrieve the heat from ammonia synthesis reactor discharging gas, and device carries in the heat of the superheater in ammonia synthesis umformer district 140).Therefore, in method E, superheated vapour is not to produce with the heat of retrieving from two sections convertor discharging gas.Improvement to the method among Fig. 1 in method F is, at the convection zone of one section convertor over-heat-exchanger is set neither and boiler is not set yet produces steam, all steam superheatings are by means of placing the superheater 152 in the ammonia synthesis reactor discharging gas and placing two sections second stage superheaters 80 in the convertor vent gas to finish.Method G has represented the improvement to method F, wherein, at one section convertor convection zone boiler is housed also.In method H, added superheater 25 at one section convertor convection zone and come method F has been done improvement at last.

With reference to table 3, the series connection superheater of arranging among the method A can with used superheater in ammonia synthesis shift zone 140 and one section convertor convection zone, but do not use the method E of two sections convertors discharging gas superheaters to compare.For method E, in order to provide steam and the energy balance value identical, the load QSHTC of ammonia synthesis shift zone superheater, the load QSHT2 of two sections convertor discharging gas superheaters among the replacement method A fully with method A.But the temperature of ammonia synthesis reactor discharging gas is more much lower than two sections convertor discharging gas, even two sections convertor discharging gas, after part had been cooled off in boiler in method A, temperature was still much lower.Therefore, just can not discharge and reach sufficiently high superheat steam temperature in the gas superheater and carry so that required heat to be provided at ammonia reactor.In the described embodiment of method E, ammonia synthesis umformer discharging temperature degree is 444 ℃, carries out thermal conduction for 10 ℃ the temperature difference is provided, and uses accessible maximum steam superheating temperature in the heat exchanger of convertor discharging gas as thermal source, is assumed to be 417 ℃.Because steam exit temperature is limited in 417 ℃, with value 85.3 gigajoules of the QSHT2 of method A/time by comparison, ammonia reactor discharging gas superheater load (QSHTC) be limited to 71.5 gigajoules/time, this makes method E lack the steam superheating ability, and that steam produces ability is superfluous.In order to make method E turn back to equilibrium state, therefore need aid burning be set, so that the extra heat load of crossing is provided at the converter convection zone.Net effect in method E is, aid burning (QAUX) cost be 28.9 gigajoules/time (efficient of supposing one-stage converter is 90%) situation under, all steam generation (S1500) is from 158307 kilograms of 166923 kilograms of rising to the method E of method A, and this is equivalent to 0.7 gigajoule (low heat value)/metric ton NH ₃Unless can find high efficiency purposes for increasing steam production, otherwise will produce the lot of energy loss, moreover the ammonia synthesis reactor that uses in method E discharging gas superheater must use the physical construction of expensive high pressure resistant shell, because two kinds of logistics all are under the high pressure, so pass through regardless of the shell-side of any logistics, all will bear high pressure on the shell from heat exchanger.

Method F～H has illustrated and has used two sections convertor discharging gas superheaters to add the effect of ammonia synthesis convertor discharging gas superheater.But method F does not comprise one section convertor convection zone boiler or superheater.The equal amount and the method C of its whole energy and steam are equal to, owing to not only do not have superheater but also do not have boiler at the convertor convection zone, the heat of available whole convection zone (when dropping to 160 ℃ stack temperature) just can not be utilized.If the recovery of heat of the convection zone that loses must compensate with the outer boiler of the device of 90% efficient, extra burning need will for 17.7 gigajoules/time, be equivalent to 0.4 gigajoule (low heat value)/metric ton NH ₃Moreover as method E sample, used ammonia synthesis reactor discharging gas superheater must be used the physical construction of expensive high pressure wall shell, therefore no matter this is because two kinds of logistics all are under the high pressure, and any logistics is passed through from the shell-side of heat exchanger, and shell wall all is under the high pressure.It should be noted that to reach with method F in same overall thermal and the balance of steam, the value of QMISC, QBOIL2, QSHT2 and QSHTC can change in quite wide scope.Transformable allowed band has been determined in note (9) (10) (11) and (14), and for example, if QSHTC is decided to be O, method F can drop to method C; If in another extreme case, QSHTC surely to it maximum value 65.6 gigajoules/time (temperature difference in the umformer discharging gas superheater is 10 ℃), in the note (9) QMISC will be 139.7 gigajoules/time, in the note (11) QSHT2 will be 28.1 gigajoules/time, in the note (10) QBOIL2 will be 162.4 gigajoules/time.Clearly, with the QMISC that calculates, the intermediate value of OSHT2 and the corresponding any QSHTC of QBOIL2 all can be used.Because all the balance of steam and energy does not change, and can select the optimum value of QSHTC, so that investment cost reduces to minimum optimum point, available general method is determined this optimum value.

Method G uses ammonia synthesis reactor discharging gas superheater, two sections convertor discharging gas superheaters and one section convertor convection zone boiler.It can produce with method A in connect preheater same whole heat and balance of steam, in fact it extremely is similar to method D.Therefore, the advantage that method A compares with method G is not the handiness according to the benefit of energy or increase quantity of steam, but has been to simplify the operation scheme of technical process.Method A and G have used two pressure vapor superheaters, but method G has also used one one section convertor convection zone boiler in addition.Except the additional components of the represented heat exchanging apparatus that goes out, the convection zone boiler need be forced the boiler water circulation system usually, and this has increased investment, process cost and the integrity problem that is equipped with boiler water circulating pump.On the contrary, as do not have the convection zone boiler, usually just can use simple natural boiler water circulation system.As method E and F, another shortcoming of method G is, the ammonia synthesis reactor discharging gas superheater that uses must use the physical construction of expensive High Pressure Shell, because two kinds of logistics all are under the high pressure, no matter so any logistics by the shell-side of heat exchanger, housing all will bear high pressure.When using as the QMISC of the note (9) of table 3 description, (10), (12) and (15), QBOIL2 when the heat of QSHT2 and QSHTC is carried scope, just can reach the whole energy described in the method G and the balance of steam.Method G just reduces to method D if QSHTC is decided to be zero (that is to say and remove ammonia synthesis reactor discharging gas superheater), under another extreme case, if QSHTC be maximum value 67.8 gigajoules/time (temperature difference in transmodulator discharging gas superheater is 10 ℃), QMISC in the note (9) be 137.5 gigajoules/time, QSHT2 in the note (12) be 29.2 gigajoules/time, the QBOIL2 in the note (10) be 161.3 gigajoules/time.What value what no matter the QSHTC load was selected is, QBOILF be 11.7 gigajoules/time, QECO be 70.6 gigajoules/time, the same with value among the method D.As method F, the available general minimum investment of the specific QSHTC value that need select optimum seeking method is tried to achieve.

Method H uses ammonia synthesis reactor discharging gas superheater, two sections convertor discharging gas superheaters and one section convertor convection zone superheater, and do not have the convection zone boiler.This also can produce the same whole energy of the superheater of connecting settled with method A and the balance of steam.Therefore, the advantage that the series connection superheater surpasses method H does not lie in the handiness that energy is benefited or increased steam production, but has simplified technical process.The few superheater of method A ratio method H, moreover, the ammonia synthesis reactor discharging gas superheater of use in method H must use the physical construction of expensive High Pressure Shell, because two kinds of logistics all are under the high pressure, so no matter the heat exchanger shell-side is passed through in any logistics, housing all will bear high pressure.As note (9) (10) (13) and (15) describing and by mutual relationship limited, method H has provided at QMISC, the heat of QBOIL2, QSHT2 and QSHTC is carried whole energy and the balance of steam that is equal in the scope, if QSHTC is decided to be zero, method H drops to the arrangement (that is, not having ammonia synthesis reactor discharging gas superheater) of the series connection superheater of method A.Under another extreme case, if QSHTC give maximum value 67.8 gigajoules fix on it/time (for the minimum 10 ℃ thermal conduction temperature difference is provided), QMISC in the note (9) will be 137.55 gigajoules/time, QSHT2 in the note (13) will be 17.5 gigajoules/time, the QBOIL2 in the note (10) will be 173.0 gigajoules/time.Any intermediate value of QSHTC all is an available, and in order to reach minimum investment, available general method is determined its optimum value.

Annotate: (3) if the convection zone waste heat recovery that loses must compensate by the boiler of 90% efficient, need 177.0 gigajoules (low heat value)/time additional fuel, be equivalent to 0.42 gigajoule/metric ton NH ₃, (gigajoule=joule * 10 ⁹, the LHV=low heat value).

(6) method E～H uses the steam superheating interchanger so that retrieve to discharge from ammonia reactor the heat of gas.Method F～H also uses two sections convertor discharging gas superheaters.

(7) suitable 0.7 gigajoule (LHV)/metric ton NH ₃

(8) in interchanger discharging gas superheater, provide 10 ℃ the thermal conduction that warm end temperature difference limited.(444 ℃ of exchanger outlet temperature and 417 ℃ of superheater temperature outs).

（9）QMISC+QSHTC＝205.3

（10）QBOIL2+QSHT2＝190.5

（11）QSHT2+QSHTC＝93.8

（12）QSHT2+QSHTC＝97.1

（13）QSHT2+QSHTC＝85.3

(14) if need minimum 10 ℃ the temperature difference in convertor discharging gas superheater, QSHTC can not surpass 65.6.

(15) if need minimum 10 ℃ the temperature difference in convertor discharging gas superheater, QSHTC can not surpass 67.8.

As mentioned above, at the relevant ammonia synthesis gas that has illustrated that method of the present invention is related, promptly contain and be suitable for as after the charging of ammonia synthesis reactor the situation with the synthetic gas of the mixture of the hydrogen of producing ammonia and nitrogen, be appreciated that, method of the present invention is equally applicable to form hydrogen-rich gas, and the explanation of front can pass through, and replaces producing and comes correct with air 32 with removing oxygen-containing gas denitrification or that do not have nitrogen.Like this, oxygen rich gas can lead to heat exchanger 26 preheatings through pipeline 32, send into two sections convertors 60 by pipeline 34 again, so that two sections oxygen that conversion reaction is required to be provided, and produce two sections convertors discharging gas 62, this discharging gas is oxygen enrichment, handle to produce superheated vapour as above-mentioned then, and through common high pressure conversion and low temperature shift, oxycarbide removes, dry or other cleansing phase commonly used, as transformation absorption, to form required hydrogen rich gas, usually contain 60～100%(volume of having an appointment, butt in the gas) hydrogen.Any transformable feed stream 6 that discussed the front all can be used as charging, and above-mentioned processing condition also are suitable for.

Therefore, illustrated the preferred embodiment of my invention when me, and with complete, analyse clearly, subtract clean and accurate language the present invention and preparation have been described, use it mode and technology so that any in the art those skilled in the art can prepare and when using it, each technician can determine essential characteristic of the present invention at an easy rate, and under situation without departing from the spirit and scope of the present invention, for adapt to various uses and condition can to the present invention make various changes and (or) improve.Therefore, this change and (or) to improve should be to belong within the equivalent scope of whole following claim.

All used pressure units of the present invention are kPa (gauge pressure), and unit of heat is a gigajoule (1 * 10 ⁹).

Claims

1, the steam conversion process of appropriate hydrocarbon gas charging comprise the charging of (a) appropriate hydrocarbon gas by with the one-stage converter of direct flame heating in the mode of hot combustion gas indirect heat exchange under the condition that heats up, carry out part and transform, one-stage converter is equipped with convection zone to reclaim the waste heat of said burning gas, (b) feeding gas that transforms of part in two sections convertors oxygen-containing gas and steam in further change into two sections convertor vent gas, it is improved one's methods and comprises, from above-mentioned two sections convertor vent gas and above-mentioned one section conversion combustion prod, reclaim used heat by following steps, (i) pass through indirect heat exchange heating high-pressure saturation steam to form first step flow of superheated steam in first step steam superheating district with the above-mentioned two sections convertor vent gas of at least a portion, (ii) in second stage steam superheating district, further heat above-mentioned first step superheated vapour to form second stage flow of superheated steam by indirect heat exchange with the above-mentioned one section convertor combustion gases of at least a portion.

According to claim 1 described improving one's methods, it is characterized in that 2, the temperature of the first step flow of superheated steam of discharging from above-mentioned first step overheated zone is about 260～510 ℃.

According to claim 1 described improving one's methods, it is characterized in that 3, the temperature of the superheated vapour that forms in the overheated zone, the above-mentioned second stage is about 316～566 ℃.

4, according to claim 1 described improving one's methods, wherein, above-mentioned two sections convertor vent gas at first are sent to steam boiler to produce high-pressure saturated steam, form two sections convertor vent gas of part refrigerative thus, and then two sections convertor vent gas of above-mentioned part refrigerative are delivered to above-mentioned first step overheated zone to produce above-mentioned first step flow of superheated steam.

5, according to claim 4 described improving one's methods, wherein, two sections convertor vent gas of above-mentioned part refrigerative temperature is about 454～816 ℃.

6, according to claim 4 described improving one's methods, it is characterized in that the high-pressure saturated steam that passes at least a portion of above-mentioned first step overheated zone is to use two sections convertor vent gas of discharging from above-mentioned first step overheated zone to produce by indirect heat exchange in the steam boiler of the second stage.

7, according to claim 1 described improving one's methods, wherein, above-mentioned two sections convertor vent gas reclaim their used heat by following processing, (ⅰ) above-mentioned two sections convertor vent gas are delivered to steam boiler and produced high-pressure saturated steam, to form two sections convertor vent gas of part refrigerative, (ⅱ) two sections convertor vent gas of above-mentioned part refrigerative are delivered in the first step steam superheating interchanger and to be produced above-mentioned first step flow of superheated steam and discharge air-flow to form two sections convertors of further refrigerative, (ⅲ) two sections convertor vent gas of above-mentioned further refrigerative are delivered in the steam superheating interchanger of the second stage so that further cool off above-mentioned convertor vent gas again, above-mentioned second stage steam superheating interchanger receives high-pressure saturated steam and forms superheated vapour therein so that above-mentioned superheated vapour is delivered to first step vapor superheater interchanger, and above-mentioned second stage steam superheating interchanger is equipped with bypass regulating device to regulate the amount by the above-mentioned high-pressure saturated steam of above-mentioned second stage over-heat-exchanger.

8, according to claim 7 described improving one's methods, wherein, above-mentioned bypass regulating device is to regulate according to the temperature of above-mentioned second stage flow of superheated steam.

9, according to claim 7 described improving one's methods, wherein, above-mentioned bypass regulating device is to regulate according to the above-mentioned temperature of further two sections convertor vent gas of refrigerative once more of discharging from above-mentioned second stage steam superheating interchanger.

10, according to claim 1 described improving one's methods, wherein, above-mentioned second flow of superheated steam is sent to steam turbine therefrom reclaiming merit, and the above-mentioned turbine of the near small part steam of discharging is delivered in the step (a) in the technical process that above-mentioned hydrocarbon feed induction part transforms.

11, according to claim 10 described improving one's methods, wherein, the steam of discharging to the steam turbine of small part delivering to above-mentioned steps (a) before earlier in convection zone further heating transform with the part that is used for the hydrocarbon feed air inlet.

12, steam reforming by the hydrocarbon feed air inlet generates in the technology of ammonia synthesis gas, (a) the hydrocarbon feed air inlet is used and is carried out part with the mode of the hot burning gas indirect heat exchange of the one-stage converter of direct flame heating under the condition that heats up and transform, one-stage converter is equipped with the unnecessary heat that convection zone reclaims above-mentioned burning gas, (b) the raw material air inlet of part conversion further transforms to form two sections convertor vent gas under the condition of air and steam existence in two sections convertors then, (c) make above-mentioned two sections convertor vent gas through conversion, hydrocarbon remove with methanation to generate ammonia synthesis gas, it is improved one's methods and comprises, from above-mentioned two sections convertor vent gas and above-mentioned one section conversion combustion prod, reclaim used heat by following steps, (ⅰ) pass through indirect heat exchange heating high-pressure saturation steam to form first step flow of superheated steam with the above-mentioned two sections convertor vent gas of at least a portion, (ⅱ) in second stage steam superheating district, further heat above-mentioned first step superheated vapour to form second stage flow of superheated steam by indirect heat exchange with the above-mentioned one section convertor hot combustion gas of at least a portion in first step steam superheating district.

13, according to claim 12 described improving one's methods, wherein, above-mentioned two sections convertors are discharged gas and at first are sent to steam boiler generation high-pressure saturated steam, form two sections convertor vent gas of part refrigerative thus, and then two sections convertor vent gas of the part refrigerative that will form are delivered to the above-mentioned first step flow of superheated steam of above-mentioned first step overheated zone generation.

14, according to claim 12 described improving one's methods, wherein, the high-pressure saturated steam that passes at least a portion of above-mentioned first step overheated zone is to use two sections convertor vent gas of discharging from above-mentioned first step overheated zone to produce by indirect heat exchange in the steam boiler of the second stage.