CN1033267C - Synthesis gas production - Google Patents

Abstract

Synthesis gas production comprising primary catalytic steam reforming a first stream of desulphurised hydrocarbon feedstock, optionally followed by secondary reforming using an oxygen-containing gas, and then cooling; adiabatically low temperature steam reforming a second stream of the feedstock, preferably adding a hydrogen-containing gas, and then subjecting the product to partial oxidation with an oxygen-containing gas, and then cooling; and mixing the cooled products. For methanol production, the partial oxidation step pressure may be greater than the primary reforming pressure, and the hydrogen-containing gas is taken from the methanol synthesis loop: if the partial oxidation step is non-catalytic and in the absence of steam, the pre-reforming stage can be omitted. Methanol can be synthesised from the reformed first and/or second streams in an auxiliary synthesis stage at an intermediate pressure before the relevant stream is added to the synthesis loop.

Description

The production method of synthetic gas

The present invention relates to be used for synthetic hydrogenous compound for example ammonia or the pure for example production method of the synthetic gas of methyl alcohol, and relate to method by the synthetic such hydrogen-containing compound of synthetic gas.

Such hydrogen-containing compound is synthetic in synthesis loop usually, wherein, under the temperature and pressure that improves, the mixture of fresh synthetic gas (being called additional gas) with circulation gas is joined in the synthesis reactor that contains the catalyzer that is suitable for building-up reactions.Then, required hydrogen-containing compound is isolated from the effusive reactant gases of synthesis reactor, for example, the synthetic gas that reacts by cooling is a liquid phase with condensation synthetic hydrogen-containing compound, and liquid phase can be separated at an easy rate.Then, will separate that remaining gas is recycled to synthesis reactor as circulation gas after the desired hydrogen-containing compound.Because it is inert component and/or excessive a certain reactant that make-up gas usually contains in building-up reactions, so portion gas will be discharged the loop as discharging gas, with avoid in gas in the synthesis loop is travelled to and fro between in circulation, increasing rare gas element or reactant excessive.Usually, part or all of vent gas is purified, to reclaim required reactant, this reactant directly is recycled to synthesis reactor as the part of circulation gas, perhaps is recycled to produce the suitable place that replenishes gas.When being used to produce the method for replenishing gas and comprising the separating step of effectively removing for example excessive a certain reactant of unwanted component or indifferent gas, vent gas can be recycled to the place that the production of separating step upstream replenishes gas.

Usually, by series of steps production make-up gas, these steps comprise hydrocarbon feed, and particularly the water vapor of Sweet natural gas or petroleum naphtha transforms.In this water vapor conversion zone, normally desulfurization of raw material is afterwards under the temperature and pressure that improves, at steam conversion catalyst, usually upload in the presence of the catalyzer of nickel and steam at for example aluminum oxide or the such coctostable substance of calcium aluminate, sometimes also with carbon dioxide reaction, obtain the gas stream of hydrogeneous, carbonoxide and methane.Conversion catalyst is placed on part or all of vent gas above-mentioned in the pipe that heats in the stove that heats with suitable fuel ignition usually and can be used as to the small part furnace fuel.

Usually, when particularly this method is used to produce ammonia synthesis gas, elementary reforming gas enters the partial oxidation step, it is called second stage conversion usually, wherein the reforming gas of the elementary conversion gas that contains free oxygen, for example oxygen itself, or air (or oxygen enrichment or oxygen-denuded air) carries out partial oxidation, at this, need be incorporated into nitrogen and replenish in the gas, for example for ammonia synthesis gas.In this second stage step of converting, partial oxidation, promptly partially combusted gas further transforms by steam conversion catalyst usually, to reduce methane content.The partial oxidation step of following by steam reforming catalysts like this is commonly referred to from thermal transition.Therefore, the required heat of endothermic conversion reaction is provided by the heat that partial combustion produces.According to specified purposes, the product gas of generation is elementary reforming gas, maybe will will further handle with the second stage reforming gas of such partial oxidation step, to obtain replenishing gas.This further processing will be depended on specified purposes.

For ammonia synthesis, additional gas need contain hydrogen and nitrogen.To contain hydrogen, nitrogen, carbonoxide, methane and argon gas with air (or oxygen enrichment or oxygen-denuded air) as the second stage reforming gas that oxygen-containing gas obtains.Therefore, for ammonia synthesis gas, this second stage reforming gas will carry out a step or the multistep shift reaction with steam usually, becomes carbonic acid gas to transform carbon monoxide, produces more hydrogen simultaneously, removes carbonic acid gas and water vapor then.Because carbonoxide, will be removed remaining carbonoxide usually as the poisonous substance of ammonia synthesis catalyst, for example remove carbonoxide by methanation.In addition, the gas of transfer can carry out catalytic selective oxidation, so that residual carbon monoxide is changed into carbonic acid gas, then, removes carbonic acid gas and water vapor.Because hydrogen and nitrogen are with 3 moles hydrogen the ratio reaction of 1 mole of nitrogen to be generated ammonia, to need hydrogen/nitrogen mol ratio be about 3 so replenish gas.Though this can be by selecting elementary and secondary conversion condition reaches so that the amount of used air is the requirement of the nitrogen introduced, but, in order to reduce the amount of the conversion that must in primary conversion reactor, carry out, the amount of used air is normally such in the step of converting of the second stage, and promptly the self-heating reforming gas contains the excess nitrogen above the needed amount of ammonia synthesis.Therefore, under these circumstances, a step of removing denitrification before make-up gas joins synthesis loop from this make-up gas is arranged usually, perhaps from the logistics that discharge in the loop, remove the step of denitrification, under latter event, excessive nitrogen is left hydrogen-rich stream from by separating in the logistics of discharging the loop.Then, this hydrogen-rich stream is got back to the loop.The nitrogen of excessive separation also can be removed some or all residual methane and argon gas (its in the ammonia synthesis process as rare gas element) usually.The gas exhaust gas stream that is generated contains excessive nitrogen and remaining methane, so it has certain fuel value, so it is normal partly or entirely as fuel of heating primary conversion reactor.

For the organic compound of synthesizing oxygen-containing, as methyl alcohol, replenish that gas is hydrogeneous, carbon monoxide and carbonic acid gas.The parameter " R " that provides by following equation

R=([H ₂]-[CO ₂])/([CO]+[CO ₂]) ([H wherein ₂], [CO] and [CO ₂] represent the mole number of hydrogen, carbon monoxide and carbonic acid gas respectively) relevant with the composition of additional gas usually.Synthetic for methyl alcohol, have " R " value and equal 2 additional gas and have stoichiometric composition.

Though second stage step of converting is not used in the preparation methyl methanol syngas usually,, its use can make synthetic gas have and be more suitable for forming in the methyl alcohol synthetic.Therefore, under the situation that lacks second stage step of converting, the raw material of consumption is a Sweet natural gas, and it is the more hydrogen of the needed hydrogen of methyl alcohol that synthetic gas will contain than transforming existing carbonoxide, and promptly " R " will be much higher than 2.Use second stage step of converting can make the value of " R " be reduced to proper level, for example a 1.8-2.2.Therefore, having been proposed in pressure in GB-A-2099846 is under the 35-55 crust (absolute pressure), use is than operation of primary conversion zone under the low temperature out of traditional temperature out, obtain a kind of gas stream that contains than higher methane content, make the gas of this elementary conversion and oxygen carry out second stage conversion then.

For, being used to prepare the organic compound of oxidation such as the synthetic gas of methyl alcohol, the second stage transforms (if using this step) reformed gas afterwards can not need further processing except cooling off and removing the water vapor.

The above-mentioned elementary step of converting that contains the catalyzer pipe that use is heated in flame heating furnace can not effectivelyly heat, and needs the equipment of big costliness.In order to reduce the load of elementary conversion system, various suggestions have been proposed, for example by the bypass of part, so that part material directly enters second stage conversion system by elementary conversion system.Therefore, in order to increase the throughput of existing apparatus, a kind of part bypass of elementary conversion system has been proposed to provide, in GB-A-2160516 for example so that part material directly is added to second stage conversion system.In GB-A-1569014, introduced a kind of similar method.The bypass of walking elementary conversion system means that also total steam ratio can reduce, to such an extent as to the volume of the gas that must be cooled that the carbonoxide of each volume produces is very little.

But, there is some difficulty in these methods, because it must mix the colder raw material of the bypass of walking elementary conversion system with the elementary reformed gas of heat, and/or to design and have second conversion system of separating device that separation joins raw material wherein in addition.There is the blended problem in such equipment of additional separation raw material, and the method that the bypass raw material is added in the elementary reformed gas of heat exists special problem, and it may need to separate by-pass stream and keep elementary and second stage conversion zone in operation.

This separating power is special needs at this, as what in above-mentioned GB-A-2160516, propose, at room temperature raw material is a for example petroleum naphtha of liquid, and the raw material of bypass and the steam of walking elementary conversion system carry out the adiabatic catalytic reaction, contains as the main gas of the methane of hydrocarbon component with generation.When bypass gas when hot product from elementary conversion system mixes, for fear of the carbon laydown that the thermally splitting owing to the hydro carbons bigger than the molecular weight of methane is easy to produce, a kind of like this insulation method (being called pre-conversion method here) is needs.Unfortunately, be used in life of catalyst in this adiabatic pre-conversion process, so pre-converting catalyst just need be than elementary or second stage conversion catalyst is changed often many generally well below the life-span elementary or second stage conversion catalyst.Therefore, only change pre-converting catalyst and do not cut off elementary and second stage conversion system with regard to needs, so, in above-mentioned device, bypass gas is mixed with the elementary reformed gas of heat after the pre-inversion section, or directly being added to second stage conversion system, this just needs some valve member can be in high-temperature operation to realize such separation.

In the present invention, by using the divided portion oxidation step, and the bypass raw material joins after the pre-inversion section in these partial oxidation steps, just can avoid the problems referred to above.Cool off the product of this divided portion oxidation panel, be added to then in any second stage conversion zone refrigerative bulk process stream afterwards of the product of handling elementary conversion system.Like this, the separation of by-pass stream can be under lower temperature (being lower than about 600 ℃) be operated with valve and is carried out.

Therefore, the invention provides a kind of method of the hydrocarbon feed production hydrogen containing synthesis gas from desulfurization, this method comprises: a). elementary catalytic steam is carried out in first logistics of said desulfurization material transform, at random then elementary reforming gas is carried out the second stage and transform, cool off first logistics of the conversion that obtains then with a kind of oxygen-containing gas; B). the pre-inversion that adiabatic water at low temperature steam reforming is carried out in second logistics of said desulfurization material, follow second logistics of the pre-inversion that obtains with the oxygen-containing gas partial oxidation, form second logistics that transforms, second logistics that cooling transforms; And c). mix first and second logistics that this refrigerative transforms.

In a preferred version of the present invention, hydrogenous gas, preferably the hydrogen-containing gas that is obtained by the synthesis loop that adds synthetic gas joined before the partial oxidation step in the gas of pre-inversion.

In the applicable special scheme of the present invention, when producing methyl alcohol by synthetic gas, the partial oxidation step is carried out being higher than under the pressure that is used for elementary step of converting, in preferred another scheme of this method, the hydrogen-containing gas logistics of being taken out by methanol synthesis loop is joined in second logistics before of partial oxidation section.In the improvement project of this scheme, the partial oxidation step may be carried out under the situation that does not have steam basically under on-catalytic, in this case, can save the pre-inversion section.

A kind of being applicable in the scheme of producing methyl alcohol of the present invention, methyl alcohol is by the or second logistics that transform, or by the mixture of first and second logistics that transform, under middle pressure, before relevant logistics joins this synthesis loop, synthetic in auxiliary synthesis stage.

Suitable hydrocarbon feed is included in that boiling point is lower than about 220 ℃ hydro carbons under the normal pressure, for example Sweet natural gas or petroleum naphtha.When producing methyl methanol syngas by the present invention, preferably the average hydrogen/carbon atomic ratio of hydrocarbon feed is greater than 2, and particularly greater than about 2.4, for producing methyl methanol syngas, Sweet natural gas is preferred hydrocarbon feed.

Before using, hydrocarbon feed should desulfurization, can make hydrocarbon feed pass through a suitable adsorbent bed, zinc oxide for example, and the hydrogen sulfide that adsorbs all existence carries out desulfurization.When raw material contains carbonaceous sulfide, make this gas by before the hydrogen sulfide adsorbent, in raw material, add a small amount of hydrogen, for example part is replenished gas or loop vent gas, and make this mixture by Hydrobon catalyst such as nickel molybdate or cobalt molybdate, make these carbonaceous sulfide change into hydrogen sulfide.

First logistics can contain the 20-95% that has an appointment, at least 30% combined feed total feed particularly, and second logistics correspondingly contains its surplus, i.e. 5-80%, particularly at least 10% combined feed total feed.For producing methyl methanol syngas, first logistics is 30-95% preferably, particularly is less than 90% combined feed total feed.

Elementary and any second stage of first logistics transforms, can be under normal condition, and with conventional steam reforming catalysts, for example on uploading the catalyzer of nickel, heat-resistant carriers such as aluminum oxide or calcium aluminate carry out.The charging of elementary conversion system generally can contain 2-6, the grammeatom hydrogen carbon in preferred 2.5-3.5 mole steam/raw material.If its source can guarantee that some steam can replace with carbonic acid gas.Pressure can be 5-45 crust (absolute pressure), and the temperature out of elementary conversion is 700-870 ℃, and the temperature out that the second stage transforms (if with) is 850-1100 ℃.But elementary conversion zone can still be used than carrying out under the low temperature out of the situation of routine at higher pressure.For example, elementary conversion zone can be that 25-45 crust (definitely), particularly 30-40 cling to (definitely) at pressure, and temperature out is 750-850 ℃, particularly 800-850 ℃ of operation down.

When second step of converting that need not first logistics is produced methyl methanol syngas, owing to use the result of higher pressure, lower temperature and steam ratio that may be low than regular situation, the methane content of elementary reforming gas will be a little than regular situation height, particularly preferably at least 5%, 6-15% (with the butt volumeter) especially.Though this relatively large methane is added to (as described below) in the synthesis loop, the part of this methane can be used as raw material and re-uses.

If with a kind of gas of nitrogenous and oxygen for example air produce ammonia synthesis gas, further transform first logistics of elementary conversion at second conversion zone, and this second reforming gas carries out one or more snippets conversion thereafter, the amount of used oxygen-containing gas can be such in second section conversion of first logistics, the hydrogen Equivalent is about 2.5 to up to 3.2 in the mol ratio of nitrogen in first logistics of i.e. second section conversion, or it is higher, for example high to 4.0.[we refer to the mole total amount of hydrogen and carbon monoxide in second reforming gas term " hydrogen Equivalent ", because most of carbon monoxide is converted into carbonic acid gas in conversion zone thereafter, and the hydrogen of production respective amount, the carbon monoxide in second reforming gas can think to be equivalent to the same molar of hydrogen].

In the method for the invention, bypass is by the part material of elementary step of converting, i.e. second logistics is through the Cryo Heat Insulation step of converting, and promptly the pre-inversion step is not considered raw material properties.This just guarantees to be present in mainly is the raw material of methane such as for example a small amount of ethane of any hydro carbons bigger than methane molecule amount in the Sweet natural gas, propane etc., is all transformed before by-pass stream stands high temperature.

In the pre-inversion step, it is the Cryo Heat Insulation steam reforming process, second feed stream with vapor mixing is preheating to the temperature that is generally 400-700 ℃, and is lower than about 650 ℃, particularly be lower than under about 550 ℃ by having the water at low temperature steam reforming catalysts of water vapor activity of conversion in temperature.Can be approximately identical at the pressure of this section operation with the used pressure of the elementary conversion of first logistics.In addition, particularly after the partial oxidation step, second logistics that transforms did not experience further chemical reaction step before compression, promptly transform, for example when producing methyl methanol syngas, what may meet the requirements is the processing of carrying out second logistics under the high pressure of pressure used in the tangible processing than first logistics, for example operates under up to the pressure of about 100 crust (definitely).The situation of production methyl methanol syngas this respect of the present invention is further introduced in the back.

For the pre-inversion of second logistics, steam is preferably less than used ratio in the elementary conversion of first logistics to the ratio of hydrocarbon carbon, and for example, the amount of steam generally is 0.5-2 in second logistics, preferred 1-2 moles per gram atom hydrocarbon carbon.Therefore, add steam more in addition in first logistics before need before steam adds, distributing the raw material of desulfurization or its elementary conversion usually.In addition, when particularly the processing of second logistics is carried out, can use the raw material of independent desulfurization under the pressure that is different from first logistics.

Used catalyzer in the catalyzer that is applicable to the Low Temperature Steam conversion zone CRG process that to be those known by the people of feed naphtha production synthetic natural gas can comprise the reduzate of the nickel oxide that is obtained by the precipitator method.Before the reduction, general catalyzer contains the nickel oxide of at least 60 (weight) %.Usually with difficult reductive element for example the oxide compound of aluminium and/or magnesium stablize nickel oxide.The compound of the co-precipitation by roasting nickel and difficult reductive element can obtain such hopcalite.The example of the compound of such co-precipitation is nickel aluminium hydroxyl carbonate or nickel magnalium hydroxyl carbonate, for example Ni ₅Al ₂(OH) ₁₆CO ₃.4H ₂O and Ni ₅MgAl ₂(OH) ₁₆CO ₃.4H ₂O.Some or whole nickel can be replaced by cobalt.

Raw material and steam carry out adiabatic reaction on low temperature conversion catalyst.So, raw material and steam heating are arrived needed temperature in, and pass through catalyst bed.Higher hydrocarbon and steam reaction generate carbonoxide and hydrogen, simultaneously, and carbonoxide and hydrogen generation methanation and form methane.End-result is that higher hydrocarbon changes into methane and forms some hydrogen and carbonoxide.Also may produce the conversion of certain heat absorption of methane, still, because the balance under low like this temperature is very favourable to forming methane, therefore, the amount of this methane conversion is seldom, to such an extent as to the product of this section is a high methane gas.The required heat of the conversion in senior footpath is that the heat by the heat release methanation of carbonoxide (steam reforming of methane and higher hydrocarbon forms) generation provides, and/or provide by the sensible heat of raw material that joins catalyst bed and steam.Therefore, temperature out will and be formed and decide by the temperature of raw material/vapour mixture, and can be to be higher or lower than temperature in.Selected condition should be such, and promptly temperature out is lower than because the temperature that inactivation limited of catalyzer.Though some catalyzer of being used always in the CRG process is being higher than about 550 ℃ of inactivations, operable other catalyzer can allowable temperature up to about 700 ℃.

Though the present invention had practicality when raw material was petroleum naphtha, but the present invention also can make raw material with Sweet natural gas, the amount of hydrocarbon that contains 2 or more carbon atoms in Sweet natural gas is generally quite when young in 10 moles of %, so it is such that the amount of thermopositive reaction takes place, so that temperature out may be low, perhaps be not higher than about 10 ℃ of temperature in.

Can remain on the level of an economy for the amount that makes the required oxygen-containing gas of the second stream portions oxidation panel, for example for ammonia synthesis, in order to use air, the amount of nitrogen can not too excessive, perhaps make " R " value within the needed scope of synthetic gas for the production oxygen-containing organic compound, what meet the requirements is that be added to the second vapor portion oxidation panel former expected high temperature, and what need is more than 500 ℃, for example 620-800 ℃.

In such heat-processed before joining the second stream portions oxidation panel, for the danger of the thermally splitting of the methane in the product that makes the Cryo Heat Insulation conversion zone reduces to minimum, preferably the hydrogeneous logistics that synthesis loop is for example taken from hydrogenous logistics was added in the product logistics before its heating, this just guarantees in the mixture that is heated to the second stream portions oxidation panel temperature in enough hydrogen is arranged, to suppress the thermally splitting of methane.The existence of hydrogen guarantees that also the spontaneous ignition temperature of mixture is enough low in the raw material that is added to the second stream portions oxidation panel, so that be easy to burn.

Therefore, on low temperature conversion catalyst, after the adiabatic reaction, in the processing of second logistics, preferably add hydrogeneous logistics, and the mixture of heating generation, for example in flame heating furnace, to the second required stream portions oxidation panel temperature in.In some cases, may be before adding hydrogeneous logistics, the high methane gas that obtains by the Cryo Heat Insulation step of converting, under than the high temperature of the used temperature of initial adiabatic reaction section, carry out a step or the adiabatic conversion of multistep, and be heated to the required temperature in of the second stream portions oxidation panel.For example, as described in US3795485 or US4383982, this gas can heat in flame heating furnace, then by a steam conversion catalyst bed, wherein produces adiabatic the conversion.So adiabatic conversion zone that can heat this gas stream more than one may be arranged between each adiabatic conversion zone.Because the Cryo Heat Insulation conversion zone generally transforms with low steam/hydrocarbon carbon ratio, so, may before the self-heating conversion zone, add a certain amount of steam in addition.When before thermal conversion step, when carrying out the steam reforming of methane-rich gas with one or more so adiabatic conversion zones, steam can add before so adiabatic step of converting.The advantage of using so adiabatic conversion zone is that the amount of oxygen-containing gas used in the second logistics self-heating conversion zone can reduce.

As mentioned above, after the Cryo Heat Insulation conversion zone and after any high-temperature heat insulation conversion zone, preferably add hydrogen-containing gas, the preferred synthesis gas that takes out by synthesis loop, and mixture heating up to the needed temperature in of the second stream portions oxidation panel.For the amount that makes the used oxygen-containing gas of the second stream portions oxidation panel reduces to minimum, it is practical preferably this oxygen-containing gas being heated as far as possible.But,, when for example being the oxygen of air separation plant production, consider that the restriction oxygen-containing gas is preheating to about 250 ℃ when oxygen-containing gas is an oxygen from metallurgical angle.Yet, with air during as oxygen-containing gas, can be very easily the temperature more than the preheating of air to 650 ℃, generally at 700-850 ℃.The temperature of raw material and oxygen-containing gas preheating, the amount of ratio that it is relative and the hydrogen-containing gas that is added should be such, so that the temperature of the mixture of charging (hydrogen-containing gas that comprises any adding) and oxygen-containing gas is higher than the spontaneous ignition temperature of this mixture.The amount of added hydrogen-containing gas is preferably such, and hydrogen richness is at least 9 (body) % in the charging of the second stream portions oxidation panel so that enter.Enter the amount of the hydrogen in the charging of partial oxidation section, promptly before adding oxygen-containing gas, long-pending at least 2.5 times of added oxysome in the partial oxidation section preferably.The operational condition of the second stream portions oxidation step is preferably: the steam/hydrocarbon carbon ratio is 1-2.5, especially 1-2, temperature out is 950-1400 ℃, especially 950-1250 ℃ (if partial oxidation is catalytic) and 1100-1400 ℃ (if partial oxidation is non-catalytic).

When for example air was produced ammonia synthesis gas, the amount of this used oxygen/oxide gas was preferably such at the gas with a kind of nitrogenous and oxygen, and the hydrogen Equivalent of (be partial oxidation section after) and the mol ratio of nitrogen are 1.0-2.0 so that second logistics that transforms.

Then, the product logistics of cooling off the second stream portions oxidation panel preferably is lower than about 500 ℃ to a certain temperature, is added in first logistics of conversion being suitable for.This can carry out very easily with the cold water chilling.Then, second logistics that refrigerative transforms is added in first logistics of refrigerative conversion, and this mixture is further processed by the requirement that production enters the additional gas of synthesis loop.In addition, cooling can comprise steam raising and/or heating of overheated, boiler feed water and/or reactant preheating.As mentioned above, this further processing will be depended on desired synthetic characteristic; For ammonia synthesis, this further processing will comprise one or more snippets shift reaction usually, remove devaporation and carbonoxide, the pressure that is compressed to synthesis loop and drying; And synthetic for methyl alcohol, this further processing will comprise usually except that devaporation and compression.When this further processing comprised shift reaction, first logistics of conversion and second logistics preferably were cooled to approximately shift temperature in before mixing.

Therefore, in a preferred version of the present invention, before first logistics that cooling transforms, make first logistics and the air of elementary conversion carry out second section conversion, shift reaction is carried out in first and second logistics that refrigerative is transformed, and removes carbonoxide, and before mixing or mix after drying.Preferably, first and second logistics that refrigerative transforms gas as a supplement enter in the ammonia synthesis loop, this ammonia synthesis loop has a catalytic ammonia synthesis section and a segregation section, and unreacting gas is recycled to synthesis stage by segregation section, in said synthesis stage, by the mixture synthetic ammonia that replenishes gas and circulation gas.

In addition, second logistics that transforms does not contain the synthetic catalyst poisonous substance, for example under the situation of methyl alcohol synthetic synthetic gas, in cooling and at random except that after anhydrating, can directly be added to second logistics that transforms in the synthesis loop, so that in the loop, carry out the mixing of first and second logistics.Therefore, in preferred version of the present invention, first and second logistics that refrigerative transforms gas as a supplement are added in the methanol synthesis loop, there are catalysis methanol synthesis stage and segregation section in this loop, and unreacting gas is recycled to synthesis stage by segregation section, in said synthesis stage, by the mixture synthesizing methanol that replenishes gas and circulation gas.

Under the situation of producing ammonia, as mentioned above, after cooling, make the second reforming gas logistics carry out a step or multistep transfer conversion usually, then, before being added to synthesis loop, remove carbonic acid gas and methanation.In the method for the invention, before it being joined in first logistics or the loop, may need to handle similarly second logistics of this conversion.Therefore, second logistics of conversion can experience one or more snippets transfer, then removes carbonic acid gas, then, before or after its methanation, second logistics of poor carbonic acid gas is added in first logistics.The transfer of second logistics is preferably in single hop, for example with the catalyst bed of heat-eliminating medium heat exchange in, under temperature out 230-280 ℃ situation, carry out.In US4721611, introduced the example of such transfer method.

In this variation scheme of present method, can be by pressure conversion absorption by removing carbonic acid gas in second logistics.Someone proposes, applying pressure conversion absorption not only can be from second logistics that shifts separating carbon dioxide, also can remove excessive nitrogen.In this variation scheme of the present invention, can adopt pressure conversion absorption to remove carbonic acid gas and excessive nitrogen simultaneously, the result is that to have removed the hydrogen of second logistics of carbonic acid gas/nitrogen mol ratio be 2.7-3.0 or bigger, it may be less expensive to remove carbonic acid gas that design pressure conversion adsorption stage is handled second logistics, but only removes the excessive nitrogen of a part.Then, can remove remaining excessive nitrogen by the ejecta of oxygen recovery zone processing ammonia synthesis loop.It is particularly advantageous improving conventional device with method of the present invention.Therefore, be added with second logistics of pre-inversion and the partial oxidation step of second logistics by use, and by adding one or more transfer legs are handled second logistics of conversion and pressure conversion adsorption stage removes carbonic acid gas and some nitrogen from second logistics that shifts, the throughput of the ammonia synthesis gas of existing apparatus can increase.If conventional device reclaims the step of hydrogen from the synthesis loop vent gas, then can add such step, make remaining excessive nitrogen and the excessive nitrogen in first logistics in second logistics can be separated.In this device, preferred conversion condition is such, so that the hydrogen of first logistics of poor carbonic acid gas/nitrogen mol ratio is 2.5-2.9, especially 2.7-2.8, and the hydrogen/nitrogen mol ratio of second logistics that shifts is 1.3-1.7, and pressure conversion adsorption stage is also removed the nitrogen of capacity except having removed carbonic acid gas, the hydrogen of second logistics of poor carbonic acid gas/nitrogen mol ratio is 1.8-2.5, especially 1.9-2.2.

As mentioned above, preferably after the Cryo Heat Insulation conversion zone and before the partial oxidation section, the hydrogen logistics is added in second logistics.Obtain in the discharge logistics that this hydrogen logistics can be taken out from the loop very easily.Synthetic indifferent gas is contained in loop ejecta circulation regular meeting; for example methane and argon gas (if air is used for the second stream portions oxidation panel and first logistics, second conversion zone) and unreacted building-up reactions thing, i.e. hydrogen and nitrogen (in the ammonia synthesis situation) or carbonoxide (in the synthetic situation of organic compound).Because methane will react in the second stream portions oxidation panel, therefore, in producing needed hydrogen logistics, do not need from discharge logistics, to remove methane.But, except there being other treatment steps to remove all excessive loop reactants, for example nitrogen, or other loop indifferent gas, for example outside the argon, need make a loop discharging gas suitable separating step of experience and/or only use part loop discharging gas that logistics enters second logistics processing as hydrogen.

The second logistics treatment unit, be Cryo Heat Insulation conversion and partial oxidation device, and relevant equipment for example is used for the oxygen-containing gas compressor of partial oxidation section, any flame heating furnace and cooling apparatus, with in above-mentioned variation scheme, shift reactor and variable-pressure adsorption equipment can be by simple and the existing first logistics primary reformer (with second convertors, if with) be connected in parallel and build and be mounted to the machinery that forms a line, to increase the ability of existing apparatus.As can be seen, install, only need least equipment to be added in the conventional device.Equally, in operation, the second logistics processing sections can be cut off and not cut off the processing of first logistics.

As mentioned above, except producing ammonia synthesis gas, the present invention is specially adapted to produce methyl methanol syngas.In the process of the bypass that does not have primary conversion reactor, elementary step of converting is usually with following conditional operation: than higher steam ratio, and for example greater than 3, general 3.0-3.5; Lower pressure, for example 10-30 crust (absolute pressure); Than higher convertor temperature out,, for example 850-880 ℃,, generally be lower than 3% (volume, butt) so that make in the reforming gas methane content lower usually above 800 ℃.Make raw material with for example Sweet natural gas, the contained hydrogen of the gas that such condition obtains is more than the synthetic needed hydrogen of methyl alcohol.Therefore, use gas material, parameter " R " significantly is higher than 2, and it represents the stoichiometric composition of methyl alcohol synthetic.The discharge gas stream that is obtained by synthesis loop can make excessive hydrogen and rare gas element discharge from synthesis loop.But, usually need to be utilized than relatively large discharging gas.

Proposed to use the transfer pressure that is similar to the methyl alcohol synthesis pressure, in fact, the pressure range of the conversion of proposition is that part is consistent with carrying out methyl alcohol synthetic pressure range.But synthetic for effective methyl alcohol, the methyl alcohol synthesis pressure is higher slightly than top pressure usually, about 45 crust (absolute pressure), and steam reforming is a kind of feasible situation in the pipe that heats in flame heating furnace under this pressure.Present methyl alcohol synthesis pressure is a low pressure, and building-up process is generally 60-120 crust (absolute pressure) generally at 50-150 crust (absolute pressure).

Therefore, make-up gas usually be lower than produce under the synthetic used pressure of methyl alcohol and joining synthesis loop before be compressed.If hydrogen is excessive in a large number, the excess hydrogen that under conventional conversion condition, is produced for example by the gas water steam reforming, then, must be compressed to the methyl alcohol synthesis pressure by transfer pressure more than the make-up gas (dry back) of 4 volumes for the methyl alcohol of every volume production.Such compression must consume lot of energy.

By the present invention, it is possible designing a kind of method of wherein wanting compressed gas volume to be reduced, therefore, the second stream portions oxidation panel can be operated under the used pressure of the elementary conversion that is higher than first logistics, in one embodiment of the invention, the self-heating conversion zone can carry out under the pressure of synthesis loop substantially.

Therefore, in preferred version of the present invention, before the partial oxidation section, second feed stream is compressed, the partial oxidation of second feed stream carries out under such pressure, promptly this pressure is higher than first logistics and carries out the required pressure of elementary conversion, and with first logistics of elementary conversion with compress before second logistics that refrigerative transforms mixes.

According to the present invention, methyl alcohol is synthetic to be that the synthetic gas that is formed by make-up gas and recycle gas in synthesis loop carries out under the synthesis pressure that raises, and separates synthetic methyl alcohol and obtains unreacted gas stream, and the part unreacting gas circulates as described circulation gas.The part make-up gas is by at the transfer pressure that raises and be lower than the first hydrocarbon feed stream that water vapor under the described synthesis pressure transforms desulfurization, then cooling, removes to anhydrate and be compressed to described synthesis pressure and obtains.Gas stream is to take out from methanol synthesis loop and at synthetic methyl alcohol separating step on the flow direction and the position between the methyl alcohol synthesis step, this logistics of taking out from the loop is as hydrogeneous logistics, this logistics with the second devulcanized hydrocarbons feed stream carried out the product that Cryo Heat Insulation transforms gained and mixes being higher than under the pressure of above-mentioned transfer pressure, mixture that obtains and oxygen logistics generation partial oxidation obtain second logistics of conversion of heat, then with this logistics cooling and turn back to the synthesis loop residuum of gas as a supplement.

For for simplicity, the gas stream that is taken out by the loop is referred to herein as and leaves loop gas (ex-loop gas).Circle round and normally undertaken by a recycle pump in the circulation of the gas of synthesis loop.This recycle pump is usually located between the methyl alcohol separating step and methyl alcohol synthesis step on the flow direction, and is used for the unreacting gas that methanol separator obtains is pushed back to synthesis pressure.Make-up gas can join in the loop before or after recycle pump.In one embodiment of the invention, portion gas from circulating-pump outlet, promptly under synthesis pressure, be removed as leaving the loop gas logistics, and join in second feed stream of sending into the part oxidation panel, turn back in the synthesis loop at the inlet of recycle pump from the refrigerative product of partial oxidation section.In this case, the second stream portions oxidation step carries out under synthesis pressure substantially.In this case, be necessary second feed stream and oxygen were compressed to about synthesis pressure before joining the partial oxidation section, if but the gas volume that must so compress is far smaller than the gas volume that second feed stream at first stands conventional primary water steam reforming.In another embodiment, wherein use the stage compression of make-up gas, particularly recycle pump wherein can not be handled the gas of the additional content that is obtained by the partial oxidation section, mix with second feed stream and join leaving loop gas and can before or after recycle pump, taking out of partial oxidation section, and turn back in the loop by joining in the make-up gas between the compression section from the product of the second stream portions oxidation panel.

The working pressure of Cryo Heat Insulation conversion zone preferably is same as the employed pressure of partial oxidation step approximately, so that do not need the pre-inversion gas compression between pre-inversion and partial oxidation step.

Leaving the loop logistics joins in the additional feed stream of compression after pre-inversion and any adiabatic conversion zone.

In the second stream portions oxidation panel of this embodiment of the present invention, the Cryo Heat Insulation conversion sound thing of second hydrocarbon stream joins the partial oxidation section with leaving loop gas, wherein steam conversion catalyst is passed through in this mixture and oxygen partial combustion then.In the variation of present method, partial oxidation can be non-catalytic, promptly can save steam conversion catalyst, and partial oxidation can carry out in the presence of the water vapor not having substantially.In some cases, when particularly wherein using the non-catalytic partial oxidation step, can save the Cryo Heat Insulation step of converting, so that second feed stream and leave loop gas and directly join the partial oxidation section.The product of partial oxidation section is cooled and turns back in the loop with the make-up gas from primary reformer in another embodiment.

Therefore, the present invention also provides a kind of method for preparing methyl alcohol in synthesis loop, wherein methyl alcohol is the synthesis gas that formed by the mixture of make-up gas and recycle gas under the synthesis pressure that raises and synthetic, separate the logistics that synthetic methyl alcohol obtains unreacting gas, the part unreacting gas circulates as described recycle gas, described make-up gas is the hydrocarbon charging by steam reforming desulfurization under the transfer pressure (it is lower than described synthesis pressure) that raises, then cooling, dewater and be compressed to described synthesis pressure and obtain, it is characterized in that gas stream is to take out at synthetic methyl alcohol separating step on the flow direction and the position between the methyl alcohol synthesis step from methanol synthesis loop, this logistics of taking out from the loop mixes being higher than under the pressure of described transfer pressure with the devulcanized hydrocarbons charging of amount in addition, mixture that obtains and Oxygen Flow adiabatic reaction obtain the hot gas logistics, cool off this hot gas logistics then and are back to synthesis loop.

As indicated above, to wish before or after adding make-up gas and from the loop, to take out and above-mentionedly from the loop, take out vent gas before or after leaving loop gas, this vent gas normally position between methyl alcohol separating step and pump entry takes out.This vent gas require to avoid unreacted methane occurring and can be present in (for example wherein charging is a Sweet natural gas) in the charging and/or oxygen stream in inert substance such as nitrogen.This vent gas can be used as the fuel of the gas turbine that drives generator or air compressor and/or is used for other heating purposes, for example the feeding preheating before the partial oxidation.The air that heats primary reformer as burning can be the hot waste gas from this gas turbine.

The preferred amounts of used oxygen is such, promptly joins the gas in the loop, and promptly partial oxidation products adds that " R " value that the make-up gas from elementary conversion zone has is in 1.8 to 2.5 scopes.

As indicated above, owing to used higher pressure, lower temperature and may be than transforming the used steam of conventional method of producing the methyl methanol syngas body by water vapor than lower steam ratio, then the methane content of elementary reformed gas will be slightly more than using the resulting methane content of ordinary method, especially preferably at least 5%, in the 6-15% scope (with the butt volumeter) especially.Though these a large amount of methane are added in the synthesis loop, the methane that leaves in the loop gas that is added to the partial oxidation section has increased the additional inlet amount that is added in the partial oxidation step.

The product logistics should be cooled to a suitable temperature before the partial oxidation step turns back to the loop, preferably be lower than about 50 ℃.This can be by heat recuperation with anxious cool and then separated liquid water and realization easily before synthetic with cold water.Heat recuperation can comprise generation and/or superheated vapour, boiler feed water heating and/or reactant preheating.

In order to increase the ability of existing apparatus, wish to use an auxiliary synthesis stage, wherein first or second logistics of Zhuan Huaing, or the mixture of two kinds of reformate stream is at middle pressure, promptly is higher than the used pressure of elementary step of converting but is lower than under the pressure used in the synthesis stage of synthesis loop and auxiliary methyl alcohol synthesis stage of experience before relevant logistics joins synthesis loop.

Therefore, in a scheme of the present invention, the product of partial oxidation step is just delivered in the auxiliary methanol sythesis reactor with more synthetic methyl alcohol without further compression.These synthetic methyl alcohol can separate in the liquid collecting jar, and the unreacting gas from this liquid collecting jar turns back in the loop then.

In another embodiment, wherein elementary reformed gas was compressed in more than a section before joining the loop, and the elementary reforming gas between these compression sections can be passed into auxiliary methanol sythesis reactor to synthesize some methyl alcohol by partial oxidation products and make-up gas.After the cooling, synthetic methyl alcohol separates in the interlude condensation separator of for example compressor, will join next compression section from the unreacting gas of this separator, sends in the loop then.In addition, second logistics of conversion, promptly partial oxidation products can join between the compression section in the elementary reformed gas of part compression.

In another embodiment, partial oxidation products in auxiliary reactor, experience methyl alcohol synthetic after, between main synthesis reactor and methanol separator, turn back in the loop.The loop methanol separator is used for the methyl alcohol that produces in separating circuit synthesis stage and the auxiliary methyl alcohol synthesis stage in this case.

When using auxiliary reactor, preferably in 40-80 crust (absolute pressure) scope, the synthesis pressure in loop is higher, preferably in 50-100 crust (absolute pressure) scope for the gaseous tension that enters the ancillary synthetic reaction device.Usually in auxiliary reactor, require the main isothermal condition of using.The reactor design that is fit to is described among EP80270 and the EP81948.

The charging that is added to synthesis reactor or reactor should be carried out necessary heating to control synthetic temperature in to desirable value, usually in 150-250 ℃ of scope; Usually can use and method from the effluent heat exchange of synthesis reactor.Being used for methyl alcohol synthetic catalyzer can be any normally used those catalyzer, for example copper/zinc oxide/alumina catalyzer.

In the accompanying drawings, Fig. 1 is a schematic flow diagram that has shown two embodiments of the present invention that are used to prepare methyl alcohol.Fig. 2 is the schema of similar Fig. 1, but has shown the embodiment of a simplification.Fig. 3 is used for the schema of correlated art methods.Fig. 4 is the schema that is used to produce the method for ammonia.

In Fig. 1, dotted line is represented first embodiment, long and short dash line (dotted lines) expression second embodiment.

With reference to figure 1, in two embodiments, the desulphurised feed material flow A is sent into through pipeline 10, is to be divided into two logistics 12 and 14 under the 30-40 crust (absolute pressure) at pressure.Flow B joins in the logistics 12 through pipeline 16, mixture heats in charging/effluent heat exchanger 18, Jia Re mixture C joins and contains the steam conversion catalyst that is contained in the conversion tube then, as is loaded in the conventional primary water steam converter 20 of the nickel catalyzator on the calcium aluminate carrier.Cooling reformed gas D reclaims heat simultaneously in heat exchanger 18 and 22, join then in the liquid collecting jar 24, and wherein excess steam is isolated as water logistics 26 and is recycled in the boiler (not shown).Product make-up gas E sends into the first step 28 of make-up gas compressor then, is compressed into middle pressure in this make-up gas, for example about 50 crust (absolute pressure), the make-up gas F that obtains compressing.

In the first embodiment, this make-up gas F mixes with cold good thermal transition gas Z (following narration) that pipeline 30 provides and then by charging/effluent heat exchanger 32.In heat exchanger 32, gas is heated to suitable temperature, and for example 150 to 250 ℃, so that enter in the auxiliary methyl alcohol synthesis converter 34 of the methanol synthesis catalyst that contains copper/zinc oxide/alumina.By water is come the cooled catalyst bed by the pipe (not shown) that is embedded in the catalyst bed, convertor 34 is remained under the basic isothermal condition, and it is remained under the pressure that makes water boiling generation steam.Methyl alcohol is synthetic by the mixture of make-up gas and self-heating reformed gas, and the effluent G of auxiliary convertor 34 is used as the heating medium in the heat exchanger 32.Effluent is further cooled off by make-up gas compressor intercooler 36 then, and sends in the middle liquid collecting jar 38 of make-up gas, and the first alcohol and water is isolated as auxiliary product stream H through pipeline 40 in jar 38.Then remaining gas J is fed the final stage 42 of make-up gas compressor, wherein gas is compressed into circuit cycle machine inlet pressure.

In second embodiment, the self-heating reformed gas is not joined among the make-up gas F between the compression section.

In two embodiments, make-up gas K from second compression section 42 mixes with the circulation gas L that pipeline 44 provides then, mixture M feeds in the circulator 46, and mixture M is compressed into the loop synthesis pressure in circulator 46, for example 80 to 100 crust (absolute pressure).Then the synthesis gas N that obtains is sent under the synthesis pressure of loop in charging/effluent heat exchanger 48, at this, mixture is heated to synthetic temperature in.The synthesis gas P of heating then joins in the loop synthesis converter 50, uses copper/zinc oxide/alumina catalyzer synthesizing methanol in convertor 50.This convertor can be quench reactor or pipe cold mould reactor.When using quench reactor, can suitably provide quench gas through pipeline 52 by the synthetic gas N before the heat exchanger 48.The effluent reactant gases Q of loop convertor 50 is used as the heating medium in the heat exchanger 48, sends into then in the water cooler 54, reclaims heat at this, for example is used for distilling thick methyl alcohol.Then the refrigerative reactant gases is fed in the separator 56, R isolates through pipeline 58 in this primary product methanol logistics, and can mix with the logistics H from auxiliary synthesis stage separator 38 and obtain product S and drain into pipeline 60.Discharging gas stream T is to take out through pipeline 62 from the unreacting gas logistics 64 of leaving separator 56, and remaining unreacting gas L forms circulation gas in pipeline 44.

In the first embodiment, the part logistics of unreacting gas is taken out as leaving the loop gas logistics through pipeline 66 from the upstream of circulator 46.As shown in Figure 1, this gas stream can take out from pipeline 44, promptly takes out before second section 42 make-up gas K from the make-up gas compressor adds, in addition, it can take out from the inlet of circulator, promptly in make-up gas K and taking-up after circulation gas L from pipeline 44 mixes.In second embodiment, leave the loop gas logistics and take out through pipeline 68 from circulator product logistics N.

In each embodiment, second logistics 14 of desulphurised feed is sent in the compressor 70, this logistics is compressed in compressor 70, mixes with the water vapor that provides through pipeline 72 then.Steam/incoming mixture U is heated to about 550 ℃ in fired heater 74 then, and contains the water at low temperature steam reforming catalysts, the adiabatic pre-converter 76 of for example Ni-based CRG catalyst bed by one.The pre-inversion gas that obtains then descends and leaves loop gas logistics V for for example about 500 ℃ in temperature, i.e. logistics 66 in first embodiment or the logistics in second embodiment 68 mix.Gaseous mixture further is heated to for example 650 ℃ in fired heater 78 then.Well heater 74 and 78 can be discharged gas T by the burning loop and be heated.The gaseous mixture W of the heating of coming out from well heater 78 takes place from thermal transition with the oxygen X that is provided by pipeline 80 the autothermal reformer 82 that contains the nickel steam conversion catalyst that is loaded on the heat-resistant carriers, self-heating reformed gas Y in heat exchanger 84 by recovery of heat, for example produce steam and cool off, obtain refrigerative self-heating reformate stream Z.

In the first embodiment, refrigerative self-heating reforming gas Z is carried by pipeline 30, and mixes with make-up gas F before make-up gas F enters heat exchanger 32 and ancillary synthetic reaction device 34.

In second embodiment, refrigerative self-heating reformed gas Z is transported in the loop through pipeline 86, and this reformed gas Z can be added in the circuit cycle logistics 44, or is added to the inlet of circulator 46, perhaps as shown in the figure, be added in second section 42 the compression make-up gas from the make-up gas compressor.

As mentioned above, in the first embodiment, second feed stream 1.4 is processed the product Z that obtains and is added in the gas stream of the elementary conversion between compression section 28 and 42 in pre-inversion and self- heating conversion zone 76 and 82, perhaps directly be added to the loop in second embodiment.The pressure that second feed stream compresses in compressor 70 should be enough, so that the pressure that is had after the processing of second feed stream through the back still is fit to it is joined in the part compression make-up gas (in first embodiment) or joins (in second embodiment) in the loop.Therefore, in the first embodiment, the pressure that is compressed in compressor 70 of second feed stream 14 should enough be higher than the transfer pressure (about 50 crust (absolute pressure)) of the first step 28 of make-up gas compressor so that the inevitable pressure drop that is produced by convertor 76 and 82 to be provided.Equally, in second embodiment, the pressure that second feed stream 14 is compressed to enough is higher than the inlet pressure of circuit cycle machine so that the pressure drop in convertor 76 and 82 to be provided.

Fig. 2 has shown the another kind of form of second embodiment of Fig. 1.In this form, heat exchanger 32 and auxiliary convertor 34 have been saved, so that make-up gas F flows to the side cooler 36 according to the first step 28 of conventionally form from the make-up gas compressor.Certainly in this case, in middle liquid collecting jar 38, will not have methyl alcohol in the isolated logistics 40, and the logistics here 40 does not mix with product R in the pipeline 58 yet.In this form, can use single-stage make-up gas compressor, and save water cooler 36, liquid collecting jar 38 and high stage compressor 42.This form also is shown among Fig. 2, and the autothermal reformer 82 among Fig. 1 is replaced by non-catalytic partial oxidation device 88, and in this case, steam supply 72, well heater 74 and pre-converter 76 in Fig. 1 embodiment all are removed.We know that first embodiment of Fig. 1 can be improved equally and use non-catalytic partial oxidation to replace from thermal transition (and economize that devaporation supplies with 72, well heater 74 and pre-converter 76).

In following table 1, provided according to the method for Fig. 2 schema calculating gas composition (whole percentage ratios like having listed recently), temperature and flow velocity (kmol/h like having listed recently) in the various stages.For simplicity, suppose that desulphurised feed is 100% methane, oxygen is pure.In practice, if with desulphurised natural gas as charging, it will have a spot of higher hydrocarbon and possible nitrogen, carbonic acid gas and hydrogen, and oxygen stream will have a spot of nitrogen usually.Suppose during calculating that elementary conversion carries out under (absolute pressure) at 30 crust, the loop is under 80 crust (absolute pressure), and partial oxidation is to carry out under 80 crust (absolute pressure).Suppose that charging and oxygen are existing at 30 crust (absolute pressure), the power requirement of calculating also is shown in Table 1.

Table 1

Logistics	Temperature (℃)	(%V/V) formed in logistics							Total flux kmol/h
										CH 4	H 2O	O 2	CO	CO 2	H 2	CH 3OH
		A B C D K U V W X Y P Q R T L	20 278 500 830 66 39 41 640 250 1150 240 270 40 40 40	100 0 25 6 9 100 35 58 0 12 35 38 2 39 39	0 100 75 37 0 0 0 0 0 7 0 0 9 0 0	0 0 0 0 0 0 0 0 100 0 0 0 0 0 0	0 0 0 7 12 0 9 5 0 24 9 6 0 6 6	0 0 0 6 9 0 3 2 0 1 3 3 1 3 3									0 0 0 44 70 0 53 34 0 55 53 49 1 51 51	0 0 0 0 0 0 1 0 0 0 1 5 87 1 1	100 100 133 180 113 67 117 184 46 322 2367 2188 103 15 2071
Make-up gas compression cycle machine CH 4+O 2Compression									Power requirement (KW)
				137 200 101

In order to contrast, with the charging of same amount (100kmol/h), produce the methyl alcohol of about same amount (89kmol/h) with the method for the prior art schema of Fig. 3, the similar results that obtains is listed in the table below in 2.In this device, catalysis autothermal reformer 82 and further heat exchanger 90 are installed between primary reformer 20 and the heat exchanger 18.Before the feed/steam mixture that is used in the reheat heat exchanger 18, in heat exchanger 90, be cooled recovery of heat simultaneously from the self-heating reformed gas Y of autothermal reformer 82.Second logistics 14 of desulphurised feed is heated the second logistics U that obtains heating in well heater 78, this logistics U mixed with elementary reformed gas D before entering autothermal reformer.In this case, suppose elementary and be to carry out under (absolute pressure), and the loop is in the operation down of 80 crust (absolute pressure) at 30 crust from thermal transition.

Table 2

Logistics	Temperature (℃)	(%V/V) formed in logistics							Total flux kmol/h
										CH 4	H 2O	O 2	CO	CO 2	H 2	CH 3OH
		A B C D U X Y K	20 278 500 710 500 200 980 66	100 0 25 13 100 0 1 1	0 100 75 49 0 0 32 0	0 0 0 0 0 100 0 0	0 0 0 2 0 0 14 21	0 0 0 6 0 0 6 9									0 0 0 30 0 0 47 69	0 0 0 0 0 0 0 0	100 180 240 287 40 48 472 320

Table 2 (continuing)

Logistics	Temperature (℃)	(%V/V) formed in logistics							Total flux kmol/h
										CH 4	H 2O	O 2	CO	CO 2	H 2	CH 3OH
		P Q R T L	240 270 40 40 40	11 13 0 14 14	0 2 20 0 0	0 0 0 0 0	9 5 0 5 5	8 7 3 8 8									71 66 1 72 72	0 8 76 1 1	1442 1264 117 25 1121
Make-up gas compression cycle machine CH 4+O 2Compression									Power requirement (kW)
				411 116 -

Calculating shows, with the reformed gas logistics D of table 1 and self-heating reformed gas Y respectively from 830 ° of its temperature outs and 115.0 ℃ of cooling requirements that are cooled to 100 ℃ much at one in the cooling requirement that the self-heating reformed gas Y of table 2 is cooled to 100 ℃ from 980 ℃ of its temperature outs.

For the benefit of using auxiliary synthesis stage is described, following example calculation is used the reduced form of schema shown in Figure 1.In this reduced form, save by-pass stream 14 and relevant treatment step thereof.Therefore, all chargings are all delivered in the heat exchanger 18, enter in the conventional primary reformer 20 as flow C then.Cool off elementary reformed gas D, remove and anhydrate, the make-up gas E that obtains sends in first compression section 28, pressurized gas F sends into auxiliary methyl alcohol synthesis stage 34 through heat exchanger 32 then, after the cooling, synthetic methyl alcohol H isolates in liquid collecting jar 38, and unreacted then gas J compresses in second compression section 42, and is added in the circuit cycle machine with circuit cycle logistics L.From the loop, do not take out logistics 66 or 68.

In this example calculation, the methane under 20 crust (absolute pressure) is as charging, and auxiliary and loop synthesis step carries out under about 40 and 100 crust (absolute pressure) respectively.Be listed in the table below in 3 at temperature (T), pressure (P), composition and the flow velocity of the different steps logistics of this process.

Table 3

	(P) crust absolute pressure	(T) ℃	(%V/V) formed in logistics						Overall flow rate kmol/h
										CH 4	CO	CO 2	H 2	H 2 O	MeOH
			C D E F G H J K M N P Q R T L S
	20 17 41 38 38 91 91 100 100 91 91 91	500 880 40 151 260 40 40 149 65 76 240 270 40 40 40 40		25.0 2.1 3.0 3.0 3.4 0.1 3.7 3.7 8.7 8.7 8.7 9.4 0.3 10.1 10.1 0.3	10.3 15.0 15.0 10.5 0.1 11.2 11.2 3.6 3.6 3.6 1.4 0.0 1.5 1.5 0.0	5.0 7.3 7.3 8.0 2.0 8.4 8.4 3.2 3.2 3.2 1.6 0.7 1.7 1.7 0.9	50.8 74.2 74.2 70.4 0.5 75.5 75.5 83.8 83.8 83.8 80.6 0.9 86.2 86.2 0.8	75.0 31.8 0.5 0.5 0.8 10.6 0.1 0.1 0.1 0.1 0.1 1.9 28.1 0.1 0.1 24.4	6.9 86.7 1.0 1.0 0.6 0.6 0.6 5.0 70.0 0.5 0.5 73.5	400.0 576.1 394.7 394.7 346.8 23.7 323.1 323.1 1469.9 1469.9 1469.9 1351.2 88.8 115.6 1146.9 112.5

In order to contrast, table 4 has been listed the charging of use same amount and has been obtained the relevant parameter of the ordinary method of same amount (82.75kmol/h) product methyl alcohol.In this ordinary method, save heat exchanger 32 and ancillary synthetic reaction device 34, so that the gas F of first compression section directly delivers in the water cooler 36.In this case, because there is not the pressure drop between the inlet of the outlet of heat exchanger 32 and auxiliary reactor 34, the first compression sections 28 and second compression section 42 to reduce.In this case, product is isolated logistics R from the loop simply, and do not comprise divide the gas between first and second compression sections dried up.

Table 4

	P clings to absolute pressure	T ℃	(%V/V) formed in logistics						Overall flow rate kmol/h
										CH 4	CO	CO 2	H 2	H 2 O	MeOH
			C D E F J K M N P Q R T L
	20 17 40 39 91 91 100 100 91 91 91	500 880 40 147 40 147 64 75 240 270 40 40 40		25.0 2.1 3.0 3.0 3.0 3.0 8.5 8.5 8.5 9.4 0.3 10.0 10.0	10.3 15.0 15.0 15.1 15.1 4.6 4.6 4.6 1.5 0.0 1.7 1.7	5.0 7.3 7.3 7.3 7.3 3.0 3.0 3.0 1.7 0.7 1.7 1.7	50.8 74.2 74.2 74.4 74.4 83.4 83.4 83.4 80.1 1.0 86.0 86.0	75.0 31.8 0.5 0.5 0.2 0.2 0.1 0.1 0.1 1.7 23.9 0.1 0.1	0.4 0.4 0.4 5.6 74.0 0.5 0.5	400.0 576.1 394.7 394.7 393.7 393.7 1771.8 1771.8 1771.8 1605.2 111.8 115.3 1378.1

The power requirement of first and second compression sections of two kinds of methods and the calculating of circulator is listed in the table 5, these calculating are to suppose that the pressure ratio in first and second compression sections in each case is identical, and the polytropic efficiency that first and second stage compressors and circulator have is 80%.

Table 5

Compressor	Power requirement (kW)
			Auxiliary synthetic	Do not have auxiliary synthetic
	First section second section circulator amounts to	367 302 143 --- 812			356 358 172 --- 886

Therefore, use auxiliary synthesis step to make compression power save 8% as can be seen in this example.

Therefore, use this auxiliary synthesis step as can be seen in the method for the invention, i.e. primary reformer is passed through in part charging bypass, and mixes with the gas that takes out from the loop, and mixture can obtain tangible benefit through the partial oxidation section then.

In the embodiment of Fig. 4, shown the synthetic of ammonia.In this embodiment.The desulphurised feed material flow A adds under the pressure of for example 30-40 crust (absolute pressure) through pipeline 10, and is divided into two logistics 12 and 14.Flow B joins in the logistics 12 through pipeline 16, the mixture that obtains heats in charging/effluent heat exchanger 18, be transported to as flow C then and contain the steam conversion catalyst that is contained in the conversion tube, for example be loaded in the conventional primary water steam converter 20 of the nickel catalyzator on the calcium aluminate carrier.Gas D with elementary conversion sends in second convertor 92 then, in this elementary reformed gas D and the burning of air X ' stream portions, and by the second steam conversion catalyst bed.Cool off the second reformed gas D ' that obtains by recovery of heat in heat exchanger 90,18 and 22 then, send into then in the mixing tank 94, the second logistics Z that the second reformed gas D ' and refrigerative transform in mixing tank 94 (below can narration) mixes.One or more levels conversion of mixture E ' process that produces, except that devaporation and carbonic acid gas, methanation, compression and drying.The further processing of this mixture is briefly by frame 96 expressions.The recycle gas L that recover hydrogen (below will narrate) that the compression make-up gas K that obtains provides with pipeline 98 then and pipeline 44 provide mixes and sends into circulator 46, is compressed into the loop synthesis pressure at this, for example 80 to 100 crust (absolute pressure).The synthesis gas N that obtains is admitted under the synthesis pressure of loop in charging/effluent heat exchanger 48, be heated to synthetic temperature at this mixture, synthesis gas P with heating sends into loop synthesis converter 50 then, uses the promoted iron ammonia synthesis catalyst of potassium synthetic ammonia in convertor 50.This convertor can be quench reactor or pipe cooling type reactor.The effluent reactant gases Q of loop convertor 50 is used as the heating medium in the heat exchanger 48, sends into water cooler 54 then, is recovered at this heat.To cool off the reacting synthesis gas body then and send into refrigerator/separator 100, and in this synthetic ammonia condensation and isolate product logistics R, discharge through managing 58, remaining unreacting gas forms recycle gas L in pipeline 44.

The part logistics of gas is taken out from the circulator outlet through pipeline 68, and sends into the ammonia scrubber of generally being represented by frame 102.The loop gas of leaving of washing is divided into two parts.A logistics is sent into deep cooling hydrogen recovery unit 106 through pipeline 104, isolates as discharging gas stream T through pipeline 62 in this exhaust gas stream that contains excessive nitrogen, some hydrogen and methane, and remaining hydrogen-rich stream turns back in the loop through pipeline 98.The utilization of another part logistics V that leaves loop gas of washing is described below.

The vapor mixing that second logistics 14 and the pipeline 72 of desulphurised feed provides, then steam/incoming mixture is heated in fired heater 74, obtain about 550 ℃ heated mixt U ', and by adiabatic pre-converter 76, this convertor 76 contains water at low temperature and steams conversion catalyst bed, for example Ni-based CRG catalyzer.The pre-inversion gas U that obtains " mixes with another part logistics V that leaves loop gas of washing down for for example about 500 ℃ in temperature, then gaseous mixture further is heated to for example 650 ℃ in fired heater 78. Well heater 74 and 78 can be discharged gas T by burning and be heated.The air X that the gaseous mixture W of well heater 78 effusive heating provides with pipeline 80 in autothermal reformer 82 takes place from thermal transition, and convertor 82 is equipped with a kind of nickel steam conversion catalyst that is loaded on the heat-resistant carriers.Then, will from the gas Y of thermal transition in heat exchanger 84 by recovery of heat, for example produce steam and cool off.Cold water Y ' logistics is added through pipeline 108, and the second logistics Z that the refrigerative that forms is transformed sends in the mixing tank 94 then.

This embodiment of the present invention column count embodiment explanation down.The composition of all gases logistics and flow velocity thereof are shown in the following table 6, wherein listed flow velocity recently like whole numerical value.Charging is the petroleum naphtha (for the purpose of calculating, supposing that it is the mixture of heptane) of desulfurization.The pressure of elementary converted feed flow C and air logistics X ' is such, so that the second gas stream D ' that transforms has about 31 crust (absolute pressure) of pressure.The mol ratio that will have hydrogen equivalent and nitrogen is that about 3.75 the second gas stream D ' that transforms was cooled to 370 ℃ before being added to mixing tank 94.

Second part of desulfurized naphtha feed stream accounts for about 20% of combined feed total feed." and the hydrogenous mixture that leaves loop gas V of washing was heated to 640 ℃ to pre-inversion gas U from pre-converter 76 before joining autothermal reformer 82 as logistics W.Produce the pre-inversion of logistics Y and be under such pressure, to carry out, so that about 32 crust (absolute pressure) of the pressure that logistics Y has from thermal conversion step.In heat exchanger 84, be cooled to 510 ℃ at 950 ℃ of second reformed gas logistics Y that leave autothermal reformer, further be cooled to 410 ℃ by adding entry logistics Y ' then by recovery of heat.The mixture Z that obtains is sent in the mixing tank 94 then.

Table 6

Logistics	Temperature ℃	Flow velocity (kmol/h)
			Nap CH 4 CO CO 2 H 2 N 2 O 2 Ar H 2O
		C D X′ D′ U′ U″ V X Y Y′ E′		460 800 480 970 450 496 42 480 950 236 381	270 0 0 0 0 0 0 0 6048 0 413 711 766 3577 0 0 0 3805 0 0 0 1 0 1370 369 16 0 0 16 1148 727 3990 1370 0 16 4186 70 0 0 0 0 0 0 0 784 0 364 3 123 81 0 0 0 535 0 2 0 0 34 12 0 3 0 0 0 0 0 0 870 234 10 0 0 6 324 162 766 882 0 13 604 0 0 0 0 0 0 0 0 1292 0 22 1472 889 4756 2252 0 29 6082

In following table 7 to 9, shown according to the method for the schema of Fig. 1 or its and improved one's methods at the flow velocity (kmol/h like listing recently) of the calculating of different steps, temperature and pressure.In these embodiments, suppose that charging is a Sweet natural gas, oxygen is pure.Except methane, Sweet natural gas also contains some higher hydrocarbons, and the hypothesis charging has following mole composition during calculating:

Methane 93.75% ethane 3.21%

Propane 0.40% butane 0.09%

The hypothesis partial oxidation was non-catalytic when nitrogen 2.20% carbonic acid gas 0.35% calculated, elementary conversion is carried out under 30 crust (absolute pressure), any auxiliary synthesis stage is in the operation down of 50 crust (absolute pressure), and the loop is synthetic to be to carry out under 80 crust (absolute pressure).In the embodiment of table 7 and 8, pre-inversion and partial oxidation are to carry out under 80 crust (absolute pressure), and in the embodiment of table 9, these steps are carried out under 50 crust (absolute pressure).In table, calculate the power requirement and be and exist under 30 (absolute pressures) and oxygen exists under the situation of the used pressure of partial oxidation step and obtains at the hypothesis Sweet natural gas.Logistics U ' that does not mark among Fig. 1 and U " represent the pre-inversion charging and the pre-inversion product of heating respectively.

Table 7 has provided the details according to the method for second embodiment of Fig. 1, promptly in this method, leaving loop gas takes out from the circulator outlet through pipeline 68, second logistics that transforms directly turns back in the loop through pipeline 86, rather than joins first logistics of conversion before being added to heat exchanger 32.The methyl alcohol that reclaims in logistics H and R is 90.7kmol/h.

Table 7

	Temperature ℃	The pressure crust	Flow velocity (kmol/h)
											CH 4	H 2O	O 2	N 2	CO	CO 2	H 2	MeOH
			A C D E F G H K L P Q R T U′ U″ V W X	20 500 830 40 60 260 40 60 40 240 270 40 40 550 504 41 640 200	30 30 - - 50 47 - 73 73 80 73 - - 80 - 80 - 80	94* 31* 10 10 10 10 0 10 232 237 237 1 5 63* 65 8 73 0	0 102 68 0 0 1 1 0 1 1 12 11 0 34 29 1 29 0	0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 46	2 1 1 1 1 1 0 1 108 110 110 0 2 1 1 4 5 0	0 0 14 14 14 8 0 8 84 159 85 0 2 0 0 5 5 0									0 0 10 10 10 9 0 9 67 81 71 2 1 0 3 3 5 0	0 0 80 80 80 66 0 66 700 894 715 1 14 0 7 30 37 0	0 0 0 0 0 6 6 1 8 9 93 85 0 0 0 0 0 0

Table 7 (continuing)

	Temperature ℃	The pressure crust	Flow velocity (kmol/h)
												CH 4	H 2O		O 2	N 2	CO	CO 2	H 2	MeOH
			Y Z	1250 40	- -	3 3	49 0		0 0	5 5	73 73										8 8	158 158	0 0
Make-up gas compression cycle machine charging compression amounts to												Power requirement (KW)
					109 138 59 306

* except the methane of this tittle, also contain some higher hydrocarbons.

Provided the details of the method for similar table 7 in the table 8, just saved auxiliary synthesis stage, be i.e. reactor 34 and heat exchanger 32.

Table 8

	Temperature ℃	The pressure crust	Flow velocity (kmol/h)
												CH 4	H 2O		O 2	N 2	CO	CO 2	H 2	MeoH
			A C D E K L P Q R T U′ U″ V W X Y Z	20 500 830 40 66 40 240 270 40 40 550 504 42 640 200 1250 40	30 30 - - 73 73 80 73 - - - - 80 - 80 - -	94* 31* 10 10 10 241 246 246 1 5 63* 65 8 73 0 3 3	0 102 68 0 0 1 1 12 12 0 34 29 0 29 0 49 0		0 0 0 0 0 0 0 0 0 0 0 0 0 0 46 0 0	2 1 1 1 1 109 112 112 0 2 1 1 4 5 0 5 5	0 0 14 14 8 90 171 92 0 2 0 5 6 0 73 73										0 0 10 10 9 73 89 78 3 1 0 3 3 5 0 8 8	0 0 80 80 66 745 953 760 1 14 7 30 37 0 158 158	0 0 0 0 1 9 9 99 90 0 0 0 0 0 0 0 0
Make-up gas compression cycle machine charging compression amounts to												Power requirement (KW)
					112 146 59 317

* except the methane of this tittle, also contain some higher hydrocarbons.

In this case, the quantity of methyl alcohol that reclaims among the logistics R is 90.3kmol/h, promptly is similar to the total recovery of table 7 embodiment.Yet the power requirement is bigger, and this shows to use in the embodiment of table 7 assists synthesis stage to save power significantly.

Provided the similar situation of first embodiment of Fig. 1 in the following table 9, in this embodiment promptly, left loop gas and take out through the recycle gas of pipeline 66 from circulator, second logistics of conversion is added in the charging of auxiliary synthesis stage through pipeline 30.

Table 9

	Temperature ℃	The pressure crust	Flow velocity (kmol/h)
											CH 4	H 2O	O 2	N 2	CO	CO 2	H 2	MeoH
			A C D E F G H K L P Q	20 500 830 40 60 260 40 60 40 240 270	30 30 - - 50 47 - 73 73 80 73	94* 31* 10 10 10 11 0 11 145 156 156	0 102 68 0 0 1 1 0 1 735 12	0 0 0 0 0 0 0 0 0 0 0	2 1 1 1 1 8 0 8 101 109 109	0 0 14 14 14 52 0 52 52 104 56									0 0 10 10 10 18 1 17 52 69 58	0 0 80 80 80 172 0 172 562 735 605	0 0 0 0 0 35 32 3 6 8 67

Table 9 (continuing)

	Temperature ℃	The pressure crust	Flow velocity (kmol/h)
												CH 4	H 2O		O 2	N 2	CO	CO 2	H 2	MeoH
			R T U′ U″ V W X Y Z	40 40 550 495 40 640 200 1250 40	- - 50 - 50 - 50 - -	0 3 63* 65 8 73 0 1 1	11 0 34 29 0 29 0 49 0		0 0 0 0 0 0 47 0 0	0 2 1 1 6 7 0 7 7	0 1 0 0 3 3 0 73 73										2 1 0 3 3 6 0 7 7	1 12 0 8 31 38 0 162 162	61 0 0 0 0 0 0 0 0
Make-up gas compression cycle machine charging compression amounts to												Power requirement (KW)
					199 105 30 334

* except the methane of this tittle, also have some higher hydrocarbons.

Quantity of methyl alcohol through pipeline H and R recovery is 93.5kmol/h.Therefore, compare with the embodiment shown in the table 7, increase in the power requirement under the condition of about 28kw, the output of methyl alcohol has increased by 3%.In addition on the one hand, oxygen only provides under 50 crust (absolute pressure), rather than 80 crust (absolute pressure), has therefore so just saved power.The special benefit of table 9 embodiment is to have reduced the gas circulation amount in the loop and reduced required circulation power.By adding auxiliary synthesis step, the output of existing apparatus will obviously increase.

Claims (3)

1. the hydrocarbon feed by desulfurization is produced hydrogenous synthetic gas method, this method comprises: elementary catalytic steam is carried out in first logistics of the raw material of said desulfurization transform and generate first reformate stream, second logistics of said desulfurization material is carried out partial oxidation with oxygen-containing gas generate second logistics that transforms, and, it is characterized in that second logistics and first logistics mixing that refrigerative transforms:

I) first reformate stream was cooled off before second logistics with the refrigerative conversion mixes; And

Ii) by following steps hydrogen was joined in second logistics before the partial oxidation step, said hydrogenation step is:

A) second logistics is carried out the pre-inversion step of adiabatic water at low temperature steam reforming, and/or

B) hydrogenous gas is joined in second logistics,

If the step a) of said pre-inversion is arranged, partial oxidation then is catalytic.

2. according to the method for claim 1, wherein second logistics is in the pre-inversion step, and obtain from the hydrogen-containing gas in the synthesis loop, said synthesis gas is provided with synthesizing and contains hydrogen production in this step, and said synthesis gas joins in second logistics before the partial oxidation step He after the pre-inversion step.

3. according to the method for claim 1 or 2, wherein, before the partial oxidation step, second feed stream is compressed, be higher than the partial oxidation that first logistics carries out carrying out under the situation of pressure of elementary conversion second feed stream at pressure, with first logistics of compressing elementary conversion before second logistics that refrigerative transforms mixes.

Images