CN100558631C - A method for preparing CO, synthesis gas and methanol by combined conversion of hydrocarbon steam - Google Patents

Abstract

The invention relates to a method for preparing CO, synthesis gas and methanol through combined conversion of hydrocarbon steam. The method adopts two series, wherein part of CO is separated from the second-stage reformed gas produced by one series through a CO separation device, and the remaining tail gas is mixed with the second-stage reformed gas produced by another series to obtain synthesis gas. The CO is used for carbonylation of methanol to acetic acid, and the synthesis gas can be used for methanol synthesis. The preparation method also includes using the high-temperature second-stage reforming gas at the outlet of the second-stage reformer to heat the stream in the tube of the heat-exchanging first-stage reformer, thereby greatly saving fuel gas consumption. The method of the invention can realize the joint production of methanol and acetic acid, and enables the natural gas resources to be recycled.

Description

A method for preparing CO, synthesis gas and methanol by combined conversion of hydrocarbon steam

technical field

The invention relates to a method for preparing CO, synthesis gas and methanol through combined conversion of hydrocarbon steam.

Background technique

Using gaseous hydrocarbons as raw materials to prepare raw material gas for ammonia synthesis, the earliest industrialized process is partial oxidation at atmospheric pressure. With the development of metallurgical technology, the processing and production of high-temperature resistant alloy conversion tubes (such as HK-40, HP-Nb) has been obtained. Solved, the gaseous hydrocarbon pressurized steam reforming process has replaced the atmospheric pressure partial oxidation process. So far, the conversion pressure has been increased from normal pressure to 3.0-4.3MPa, and the production scale is becoming larger and larger. The largest single-series synthetic ammonia in the world today is 1700MTPD, and the largest single-series methanol is above 2540MTPD. The traditional synthesis gas preparation process, whether it is the atmospheric pressure partial oxidation method or the pressurized continuous reforming process, is to directly introduce the high-temperature secondary reforming gas into the waste heat boiler to generate high-parameter steam, and the heat required for the steam reforming of gaseous hydrocarbons has to rely on Combustion of a part of hydrocarbons to solve.

The core of the energy-saving process is to reduce the consumption of hydrocarbons for combustion as much as possible, so as to realize the autothermal balance or semi-autothermal balance of the conversion process (the former is such as the LCA process and the heat exchange first-stage conversion string oxygen-enriched air second-stage conversion process , the latter such as hydrocarbon steam heat exchange series conversion process and this process).

In order to realize the autothermal balance or semi-autothermal balance of the conversion process, since the 1980s, foreign countries have started to develop the heat exchange conversion gas production process. The earliest to achieve industrialization is the LCA process of the British ICI company, and its production scale is 300-450MTPD. This process uses a heat exchange reformer to replace the traditional externally heated primary reformer, and shifts part of the CH ₄ steam reforming load of the primary reformer to the secondary reformer, adding excess air to the secondary reformer to maintain the system Self-heating balance, while using the high-temperature secondary reforming gas from the secondary reformer to exchange heat between the outside of the tube of the heat-exchanging primary reformer and the reactants in the tube to provide the heat required for the steam reforming reaction of hydrocarbons in the tube. In order to meet the requirement of H ₂ /N ₂ in the feed gas for the ammonia synthesis reaction, a PSA device is installed to remove the excess nitrogen brought into the system along with the excess air, and also remove CO ₂ gas. The LCA process causes a certain amount of H ₂ loss in the process of removing excess N ₂ . In order to overcome this shortcoming, the Grodno Nitrogen Complex Enterprise in Belarus adopts a heat exchange type primary reformer followed by a series of oxygen-enriched air secondary Stage reforming process, so as to achieve the purpose of self-heating balance of the system, and there is no problem of H ₂ loss, but another set of PSA air separation (or air separation) device needs to be installed.

At the end of the last century, I.C.I successfully developed the LCM process for the production of methanol synthesis gas on the basis of the LCA process, that is, the excess air is replaced by adding pure oxygen in the secondary reformer. At the same time, in China, the heat exchange-type oxygen-enriched air conversion ammonia synthesis raw material gas, the heat-exchange parallel conversion and heat-exchange series conversion to prepare ammonia synthesis gas, and the heat-exchange pure oxygen two-stage conversion have also been successfully developed in China. Synthetic raw material gas for methanol production by process and heat exchange type parallel conversion series pure oxygen two-stage conversion for methanol synthetic raw material gas.

However, in the above-mentioned processes, natural gas resources are not fully utilized, methanol production cannot be combined with methanol carbonylation acetic acid production, a large amount of fuel gas is burned, and the problem of hydrogen and carbon imbalance cannot be fundamentally solved.

Contents of the invention

The main purpose of the present invention is to make full use of natural gas resources, to combine methanol production and methanol carbonylation acetic acid production, fundamentally solve the problem of hydrogen and carbon imbalance, and realize resource recycling, reduce fuel gas consumption, save energy and reduce energy consumption. consumption, reduce investment and shorten construction period.

In order to achieve the above object, the present invention provides a method for preparing CO and synthesis gas by combined conversion of hydrocarbon steam. The feed gas containing hydrocarbons used in the method is natural gas, liquefied petroleum gas or gas gas. The process is as follows :

1) Two series A and B are adopted. In series A, the raw material gas containing hydrocarbons is mixed with steam and enters an external heat type primary reformer and a heat exchange type primary reformer respectively. The external heat type The primary reformer and the heat exchange primary reformer jointly complete the primary steam reforming reaction of hydrocarbons. The heat required for the steam reforming reaction in the heat exchange primary reformer comes from the high-temperature secondary reforming gas generated by the primary secondary reformer. Heat energy, which is obtained through the indirect heat exchange between the high-temperature secondary reforming gas and the reactants in the tube of the heat-exchanging primary reforming furnace. The steam-like reforming reaction provides heat, and the first-stage reforming gas generated by the heat exchange type primary reformer and the external heat type primary reformer is mixed and then enters the second-stage reformer to carry out _CH4 deep reforming reaction; in the B series, including The feed gas of hydrocarbons is mixed with steam, preheated by an inlet/outlet heat exchanger, and then enters a heat-exchanging primary reformer for a primary steam reforming reaction. The steam reforming reaction in the heat-exchanging primary reforming furnace requires The heat comes from the high-level thermal energy of the high-temperature second-stage reforming gas generated by the first-stage reformer, and the heat is obtained through the indirect heat exchange between the high-temperature second-stage reforming gas and the reactants in the tube of the heat-exchanging first-stage reformer. The first-stage reforming gas generated by the reaction in the heat-exchanging type first-stage reformer enters the second _- stage reformer for CH deep conversion reaction; respectively, _CO is added to the two second-stage reformers in the A and B series. To adjust the H ₂ /C ratio of the high-temperature secondary reforming gas generated, the CO ₂ is recovered from the combustion flue gas of the externally heated primary reformer in the A series, and the combustion flue gas is recovered Before CO ₂ , _CO preheating coils, hydrocarbon gas/steam preheating coils, hydrocarbon gas preheating coils, oxygen preheating coils and The combustion-supporting air preheats the coil for heat exchange, and enters the flue gas recovery _CO2 device after its own temperature is lowered;

2) After the high-temperature secondary reforming gas generated by the secondary reforming furnace described in the B series provides heat to the heat exchange type primary reforming furnace, the temperature is lowered by the heat recovery equipment and then enters the CO separation device to separate out Part of CO; the high-temperature secondary reforming gas generated by the secondary reforming furnace described in series A provides heat to the heat-exchanging primary reforming furnace, passes through heat recovery equipment, and is combined with the secondary reforming furnace described in series B The tail gas after separating part of CO from the secondary reforming gas is mixed and used as synthesis gas.

In the above method, the feed gas described in the two series A and B are independent of each other, the molar ratio of steam to the total carbon in the feed hydrocarbon is 1.8-4.5 for the A series, 1.0-4 for the B series, and enters the A series. The pressure of the mixture of raw material gas and steam in the heat exchange type primary reformer, the external heat type primary reformer and the heat exchange type primary reformer described in the B series is 0.2-4MPa, and the temperature is 400-600°C; A The temperature of the primary reforming gas at the outlet of the heat exchange primary reformer described in the series and the heat exchange primary reformer described in the B series is 500-750°C, and the dry basis volume ratio of CH ₄ in it is 12-26 %; the temperature of the first-stage reformed gas at the outlet of the externally heated first-stage reformer tube in A series is 700-800°C, and the volume ratio of CH ₄ in it is 3-12% on a dry basis; The temperature of the second-stage reforming gas at the outlet of the first-stage reformer and the second-stage reformer in series B is 800-1050°C.

In the above method, the moles of CO added to the _second -stage reformer in series A are 0 to 25% of the total carbon moles of the raw material gas of series A, and do not contain 0; The mole number of _CO2 added in the furnace is 0-45% of the total carbon mole number of the raw material gas, and does not contain 0.

The gas composition of the synthesis gas obtained by the above preparation method can meet the following conditions, and can be used in the low-pressure methanol synthesis process:

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; C</span>}{\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; CO</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; CO</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2.05</span>}<span\; class="notranslate">\; ~</span>\mathrm{<span\; class="notranslate">\; 2.15</span>}$

In the formula: f-ratio, no unit,

H ₂ - molar flow rate of hydrogen, kmol/h,

CO ₂ - molar flow rate of carbon dioxide, kmol/h,

CO-molar flow rate of carbon monoxide, kmol/h.

The CO prepared by the above preparation method can be used as raw material gas for methanol carbonylation of acetic acid, and the obtained synthesis gas can be used as raw material gas for methanol synthesis.

The present invention also provides a method for preparing methanol by combinatorial conversion of hydrocarbon steam, the process of which is as follows:

1) Two series, A and B, are used. In series A, the raw material gas containing hydrocarbons and the purge gas generated during the synthesis of methanol are separated and mixed with _H2 and then mixed with steam to enter an external chamber respectively. A heat-type primary reformer and a heat-exchange primary reformer, the external heat-type primary reformer and the heat-exchange primary reformer jointly complete the primary steam reforming reaction of hydrocarbons, and the heat-exchange primary reformer internally steam reforms The heat required for the reaction comes from the high-level thermal energy of the high-temperature second-stage reforming gas generated by the first-stage reformer. Obtained, the externally heated primary reforming furnace provides heat for the steam reforming reaction of hydrocarbons by burning fuel gas through the burner, and a part of the fuel gas comes from the purge gas produced in the methanol synthesis process after separating _H2 and _CO2 Tail gas; the first-stage reforming gas generated by the reaction in the heat exchange type primary reformer and the external heat type primary reformer is mixed and then enters the second _- stage reformer for CH deep reforming reaction; in the B series, the raw material containing hydrocarbons After the gas is mixed with steam, it is preheated by an inlet/outlet heat exchanger, and then enters a heat exchange type primary reformer for a stage of steam reforming reaction. The heat required for the steam reforming reaction in the heat exchange type primary reformer comes from the first and second stages The high-level thermal energy of the high-temperature second-stage reforming gas generated by the reformer is obtained through the indirect heat exchange between the high-temperature second-stage reforming gas and the reactants in the tube of the heat-exchanging first-stage reformer. The first-stage reforming gas generated by the reaction in the reformer enters the second-stage reformer for CH ₄ deep reforming reaction; the purge gas generated during methanol synthesis is added to the second-stage reformer in the two series of A and B respectively and separated The obtained CO ₂ gas is used to adjust the H ₂ /C ratio of the generated high-temperature secondary reforming gas, and the CO ₂ is recovered from the combustion flue gas of the externally heated primary reforming furnace mentioned in series A, so Before the above combustion flue gas is recovered _CO , the _CO preheating coil, hydrocarbon gas/steam preheating coil, and hydrocarbon gas preheating coil provided with the convection section of the externally heated primary reformer , Oxygen preheating coil and combustion air preheating coil for heat exchange, after their own temperature is lowered, enter the flue gas recovery CO ₂ device;

2) After the high-temperature secondary reforming gas generated by the secondary reforming furnace described in the B series provides heat to the heat exchange type primary reforming furnace, the temperature is lowered by the heat recovery equipment and then enters the CO separation device to separate out Part of CO; the high-temperature secondary reforming gas generated by the secondary reforming furnace described in series A provides heat to the heat-exchanging primary reforming furnace, passes through heat recovery equipment, and is combined with the secondary reforming furnace described in series B The tail gas after separating part of CO from the secondary reforming gas is mixed and used as synthesis gas. The H ₂ , CO ₂ -enriched gas and tail gas obtained by separating the purge gas produced in the process of preparing methanol from the synthesis gas are returned to the synthesis gas preparation process to realize resource recycling.

The devices (or methods) that can be used to separate CO from the cooled second-stage outlet gas in the above-mentioned preparation method include PSA separation and adsorption devices, cryogenic separation of CO, or complex absorption separation of CO. It is recommended to use PSA separation and adsorption device.

In the preparation method, the steam reforming reaction of methane and other hydrocarbons in the heat exchange type primary reformer tube and the traditional external heating type primary reformer tube is as follows:

In the secondary reformer, since pure oxygen, CO ₂ gas and methane and other hydrocarbons are added to the secondary reformer, the steam reforming reaction is:

The synthesis gas obtained by the preparation method can be used as raw material gas in the joint production process of methanol and acetic acid, and can also be used to produce methanol alone. At the same time, it can provide high-purity CO product gas with a purity of 99.8% to other users. The present invention has the following characteristics:

1. This preparation method is superior to the traditional externally heated steam reforming process. It can use the high-level thermal energy of the outlet gas of the second-stage reformer to heat the reactants in the tube of the heat-exchanging first-stage reformer to provide the necessary heat for its steam reforming reaction. It greatly reduces the fuel natural gas consumption and flue gas emission of the externally heated reformer. Of course, it also reduces the heat loss caused by flue gas emission. For the A series, it basically realizes half of the hydrocarbon steam reforming reaction process Self-heating balance; for the B series, in addition to the energy-saving effect brought by the heat-exchanging primary reformer, at the same time, the process waste heat of the secondary-stage reforming gas between the tubes of the heat-exchanging primary reformer can also be used to convert natural gas /Process steam mixture is preheated to the inlet temperature of the heat exchange type primary reformer. As a heating furnace for raw material gaseous hydrocarbons and process oxygen and _CO2 preheating, its heat load is extremely low, and its fuel gas can be either a small amount of hydrocarbons or methanol synthesis purge gas recovered by _H2 and _CO2 After the exhaust gas, or the mixture of the two, it is difficult to see the smoke emission with the naked eye at the production site. Therefore, the B series basically realizes the autothermal equilibrium of the hydrocarbon steam reforming reaction process.

2. Since the amount of raw materials and other production control parameters in each reformer of the A and B series can be adjusted independently, the amount of separated CO ₂ can also be controlled, thus fundamentally solving the problem of hydrogen and carbon imbalance.

3. High thermal efficiency

This preparation method transfers part of the _CH4 steam reforming from the primary reformer to the adiabatic secondary reforming with thermal efficiency close to 100%.

4. It can realize the joint production of methanol and acetic acid and realize the recycling of resources.

5. Small risk, stable and reliable operation. A and B series can be produced separately, or can be produced with different production control parameters.

Description of drawings

Fig. 1 is a system and process flow diagram for preparing CO, synthesis gas and methanol by the method of the present invention.

Detailed ways

Referring to Fig. 1, the feed gas enters the feed gas preheating coil in the convection section of the externally heated primary reformer 9a through the pipeline 1a (or after being mixed with the _H separated from the methanol synthesis purge gas from the pipeline 3a) for preheating to 250-430°C, and then enter the hydrodesulfurization reactor 6a through the pipeline 5a to remove sulfur harmful to the subsequent process, and the reactor is equipped with a catalyst. The desulfurized gas flows out from the pipeline 7a and is mixed with the process steam (pressure 0.3-4.5MPa) from the pipeline 23, which is the process raw material gas, and enters the natural gas/steam preheating plate in the convection section of the externally heated primary reformer 9a tube, the temperature rises to 400-600°C, the pressure is 0.2-4Mpa, and enters the reforming tubes of the externally heated primary reforming furnace 9a and the heat-exchanging primary reforming furnace 10a respectively through the pipeline 8a, and these reforming tubes are equipped with catalyst. In the heat-exchanging primary reformer 10a, with the help of the heat provided by the high-temperature secondary reforming gas from the secondary reformer 14a between the reforming tubes, the raw material hydrocarbons and water vapor undergo a chemical reaction to generate CO and H ₂ . In the thermal primary reformer 9a, the raw material hydrocarbons in the reforming tube still use the burners installed on the furnace top (or furnace wall) to burn a certain amount of combustion heat of the fuel gas from the pipeline 25a to maintain its reforming reaction with steam. required heat. When the respective conversion reactions of the two first-stage reformers 9a and 10a have been carried out to a certain extent, they flow out from the outlet pipe 11a and merge into the second-stage reformer 14a through pipelines 12a and 13a. Catalysts are housed in the second-stage reformer. The temperature of the first-stage reforming gas at the outlet of the reformer 10a is 500-750°C, and the dry basis volume ratio of _CH in the first-stage reforming gas is 12-16%; the temperature of the first-stage reforming gas at the outlet of the externally heated first-stage reformer 9a is At 700-800°C, the dry basis volume ratio of CH ₄ in the reformed gas at this stage is 3-12%. Process oxygen is mixed with a small amount of steam from pipeline 23 through pipeline 2a, and then enters the convection section of externally heated reformer 9a to be preheated to 250-350°C, enters the second-stage reformer 14a through pipeline 15a, and is combined with the first-stage reformer from pipeline 13a. After the reformed gas is violently turbulently mixed, the combustion reaction of hydrogen and oxygen occurs at the top of the furnace first, providing the necessary heat for the subsequent deep reforming reaction of methane. The CO ₂ recovered from the flue gas of the externally heated primary reformer 9a is mixed with a small amount of steam from the pipeline 23 through the pipeline 4a, and then enters the convection section of the externally heated reformer 9a. 27a is mixed with the first-stage reforming gas from pipeline 13a and then enters the second-stage reformer. Part of the desulfurized feed gas that does not pass through the primary reformer enters the furnace head of the secondary reformer through the pipeline 22a, and is turbulently mixed with the primary reforming gas and process oxygen at the same time, and undergoes partial oxidation reaction in the non-catalytic conversion reaction space . When the second-stage reforming reaction has progressed to a certain extent, that is, when the outlet temperature reaches 800-1050°C, the outlet gas of the second-stage reformer enters the tube of the heat-exchanging primary reformer 10a through the pipeline 16a, and transfers high-level process waste heat to the reaction in the tube After its own temperature drops to 500-750°C, it enters the A-end of the reforming gas waste pot 24 through the pipelines 17a and 18a, and further recovers the heat in the reforming gas in the form of by-product steam, and then passes through the BFW preheater 20a and the water cooler 21a. The temperature drops to about 40°C and is sent through pipeline 28 to be used as raw material gas for methanol synthesis.

The raw gaseous hydrocarbons pass through the pipeline 1b (or after being mixed with the _H2 separated from the methanol synthesis purge gas from the pipeline 3b), enter the heating furnace 9b to be preheated to 330-410°C, and the gaseous hydrocarbons enter the hydrodesulfurization tank 6b through the pipe 5b to To remove sulfur harmful to the subsequent process, the reactor is equipped with a catalyst. The desulfurized gas flows out through the pipeline 7b and is mixed with the process steam from the pipeline 23 (steam pressure is 0.3-4.5MPa), which is the process raw material gas, and enters the inlet/outlet heat exchanger 19 to be preheated to 400-600°C. 0.2 ~ 4Mpa, enter the reforming tube of the heat exchange type primary reformer 10b from the pipeline 8b, the reforming tube is equipped with catalyst, in the heat exchange type primary reformer tube, with the help of the high temperature secondary The heat provided by the stage reforming gas makes the raw material hydrocarbons react with water vapor to produce CO and H ₂ . When the conversion reaction of the heat-exchanging primary reformer 10b has progressed to a certain extent, it flows out through the outlet pipe 11b, and enters the adiabatic secondary reformer 14b through the pipelines 12b and 13b. The secondary reformer 14b is filled with catalyst, wherein The temperature of the primary reforming gas at the outlet of the thermal primary reforming furnace 10b is 500-750° C., and the volume ratio of CH ₄ in the primary reforming gas is 12-16% on a dry basis. Process oxygen enters the heating furnace 9b through the pipe 2b, preheats it to 250-350°C, and enters the top of the second-stage reformer 14b through the pipeline 15b, where it is turbulently mixed with the first-stage reforming gas from the pipeline 13b. The combustion reaction of hydrogen and oxygen occurs at the top, which provides the required heat for the subsequent methane deep conversion reaction, and the partly desulfurized raw material gas from the pipeline 22b enters the secondary reformer for partial oxidation in its non-catalytic reaction space Reaction, the CO ₂ gas recovered from the flue gas of the externally heated primary reformer 9a enters the heating furnace 9b through the pipeline 4b, is preheated to 100-200°C, passes through the pipeline 27b, mixes with the primary reforming gas from the pipeline 13b, and then enters the secondary The stage reformer 14b performs the steam reforming reaction of CH ₄ +CO ₂ . The pure oxygen (mixed with a small amount of steam) from the pipeline 2b is preheated in the heating furnace 9b to 250-350°C and enters the second-stage reformer through the pipe 15b. At its top, oxygen is turbulently mixed with the first-stage reforming gas and natural gas, and combustion occurs reaction. When the conversion reaction in the second-stage reformer has progressed to a certain extent, that is, when the outlet temperature reaches 800-1050°C, the outlet gas of the second-stage reformer 14b enters the tube of the heat-exchanging first-stage reformer 10b through the pipeline 16b, and transfers the waste heat of the high-level process The reactant in the supply tube, its own temperature drops to 500-750°C and enters the inlet/outlet heat exchanger through pipeline 17b to preheat the raw material gas to 400-600°C, after its own temperature is lowered again, it enters the reforming gas waste boiler 24 through pipeline 18b At the B end, the heat in the reformed gas is further recovered in the form of by-product steam, and then the reformed gas is cooled to about 40°C by water through the boiler feed water preheater 20b and the water cooler 21b, and then enters the PSA pressure swing adsorption separation device 29, and Part of the CO in the reformed gas is separated and sent to be used as raw material gas for carbonylation of methanol to acetic acid. The tail gas after CO separation contains a large amount of effective components such as H ₂ , CO ₂ and CO. The gas is mixed and sent to make methanol synthesis gas. The output of methanol is controlled by adjusting the size of the PSA auxiliary line valve. The steam by-produced by the reforming gas waste boiler 24 is sent to the main pipe by the pipeline 23 after being separated from water by the steam drum.

In the above process, the moles of CO _and hydrocarbon-containing feed gas added to the secondary reformer 14a are respectively 0-25% and 0-28% of the total carbon moles of the feed gas entering through the pipeline 1a to the CO added in the second stage reformer _14b The moles of the feed gas containing hydrocarbons are respectively 0～45% and 0～35% of the total carbon moles of the feed gas entering through the pipeline 1b; The amount of pure oxygen added to the reformer 14b should be able to maintain the thermal balance of the system and ensure that the volume ratio of CH ₄ in the secondary reforming gas is 2-0.3% on a dry basis.

The synthesis gas obtained by mixing the tail gas after separating part of CO from the PSA separation unit and the reformed gas from the pipeline 28. In the process of synthesizing methanol, the H ₂ , CO _2- rich gas and tail gas are separated from the purge gas generated. Return to pipelines 3a and 3b (H ₂ ), pipelines 4a and 4b (CO ₂ ) and 25a and 25b (tail gas as fuel gas) respectively to realize resource recycling.

Since the amount of raw materials in each reformer and other production control parameters can be adjusted independently in this process, the amount of separated _CO2 can also be controlled, so it can be guaranteed that the obtained synthesis gas can be used in the low-pressure methanol synthesis process.

Finally, it should be noted that the above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the present invention can still be modified and \or equivalent substitutions without departing from the spirit and scope of the invention.

Claims (6)

1, a kind of hydrocarbon vapours built-up type transforms the method for preparing CO and synthetic gas, it is characterized in that:

1), adopt A, two series of B, in the A series, an external-heat one-stage converter that enters respectively after the unstripped gas of hydrocarbon-containifirst material and the vapor mixing and a heat exchange type one-stage converter, described external-heat one-stage converter and heat exchange type one-stage converter are finished one section steam reforming reaction of hydrocarbons jointly, steam reforming reaction institute heat requirement is from the high level heat of two sections reforming gas of high temperature of secondary reformer generation in the described heat exchange type one-stage converter, this heat obtains by the indirect heat exchange between two sections reforming gas of described high temperature and the described heat exchange type one-stage converter inner reaction tube thing, described external-heat one-stage converter is chewed combustion fuel gas by burning, for the hydrocarbon steam conversion reaction provides heat, enter described secondary reformer after one section reforming gas that reaction generates in described heat exchange type one-stage converter and the external-heat one-stage converter mixes and carry out CH ₄Degree of depth conversion reaction; In the B series, the unstripped gas of hydrocarbon-containifirst material and vapor mixing are after after the import/export interchanger preheating, enter a heat exchange type one-stage converter and carry out one section steam reforming reaction, steam reforming reaction institute heat requirement is from the high level heat of two sections reforming gas of high temperature of secondary reformer generation in the described heat exchange type one-stage converter, this heat obtains by the indirect heat exchange between two sections reforming gas of described high temperature and the described heat exchange type one-stage converter inner reaction tube thing, and one section reforming gas that reaction generates in the described heat exchange type one-stage converter enters described secondary reformer and carries out CH ₄Degree of depth conversion reaction; Secondary reformer in described A, B two series adds CO respectively ₂Gas is in order to regulate the H of the two sections reforming gas of high temperature that generate ₂/ C ratio, described CO ₂Be to reclaim from the combustion product gases of external-heat one-stage converter described in the A series, described combustion product gases is reclaiming CO ₂Before, the CO that is provided with the convection zone of described external-heat one-stage converter ₂Preheat coil, hydro carbons gas/steam preheating coil pipe, hydro carbons gas preheat coil, oxygen preheat coil pipe and the heat exchange of combustion air preheat coil enter stack gas after self temperature reduces and reclaim CO ₂Device;

2), after two sections reforming gas of high temperature of generating of the secondary reformer described in the B series offer described heat exchange type one-stage converter with heat, after reducing temperature, heat recovery equipment enters the CO tripping device again, cutting out partial CO; After two sections reforming gas of high temperature that secondary reformer described in the A series generates offer described heat exchange type one-stage converter with heat, through heat recovery equipment, mixes with the tail gas behind two sections reforming gas separate part CO of the described secondary reformer of B series, be used as synthetic gas.

2, hydrocarbon vapours built-up type according to claim 1 transforms the method for preparing CO and synthetic gas, it is characterized in that the unstripped gas described in two series of A, B is separate, the mol ratio of total carbon is 1.8～4.5 for A series in steam and the unstripped gas, for B series is 1.0～4, the pressure that enters the gas mixture of interior unstripped gas of heat exchange type primary reformer tubes described in heat exchange type one-stage converter described in the A series and described external-heat one-stage converter and the B series and steam is 0.2～4MPa, and temperature is 400～600 ℃; The temperature of one section reforming gas in the exit of heat exchange type one-stage converter is 500～750 ℃ described in heat exchange type one-stage converter described in the A series and the B series, CH ₄Butt volume ratio therein is 12～26%; The temperature of one of the exit of external-heat primary reformer tubes section reforming gas is 700～800 ℃ described in the A series, CH ₄Butt volume ratio therein is 3～12%; The temperature of two sections reforming gas in the exit of secondary reformer is 800～1050 ℃ described in secondary reformer described in the A series and the B series.

3, hydrocarbon vapours built-up type according to claim 1 and 2 transforms the method for preparing CO and synthetic gas, it is characterized in that the CO that adds in described secondary reformer in the A series ₂Mole number be 0～25% of A series raw material gas total carbon mole number, and do not contain 0; The CO that in described secondary reformer, adds in the B series ₂Mole number be unstripped gas total carbon mole number 0～45%, and do not contain 0.

4, hydrocarbon vapours built-up type according to claim 1 and 2 transforms the method for preparing CO and synthetic gas, it is characterized in that the H in the described synthetic gas ₂, CO and CO ₂Gas composition meets the following conditions, and is used for the low pressure methanol synthesis technique:

$f=\frac{H_2-{\mathrm{CO}}_2}{\mathrm{CO}+{\mathrm{CO}}_2}=2.05～2.15$

In the formula: f-ratio, no unit,

H ₂The molar flow of-hydrogen, kmol/h,

CO ₂The molar flow of-carbonic acid gas, kmol/h,

The molar flow of CO-carbon monoxide, kmol/h.

5, the synthetic gas of the described method preparation of a kind of claim 1 is as the methyl alcohol synthetic raw gas.

6, a kind of hydrocarbon vapours built-up type transforms the method for preparing methyl alcohol, it is characterized in that:

1), adopt two series of A, B, in the A series, the off-gas that produces in the unstripped gas of hydrocarbon-containifirst material and the methyl alcohol building-up process is through separating the H that obtains ₂After the mixing again with vapor mixing after the external-heat one-stage converter and the heat exchange type one-stage converter that enter respectively, described external-heat one-stage converter and heat exchange type one-stage converter are finished one section steam reforming reaction of hydrocarbons jointly, steam reforming reaction institute heat requirement is from the high level heat of two sections reforming gas of high temperature of secondary reformer generation in the described heat exchange type one-stage converter, this heat obtains by the indirect heat exchange between two sections reforming gas of described high temperature and the described heat exchange type one-stage converter inner reaction tube thing, described external-heat one-stage converter is chewed combustion fuel gas by burning and is provided heat for hydrocarbon steam conversion reaction, the part of described fuel gas from the off-gas that produces in the methyl alcohol building-up process through separating H ₂And CO ₂After tail gas; Enter described secondary reformer after one section reforming gas that reaction generates in described heat exchange type one-stage converter and the external-heat one-stage converter mixes and carry out CH ₄Degree of depth conversion reaction; In the B series, the unstripped gas of hydrocarbon-containifirst material and vapor mixing are after after the import/export interchanger preheating, enter a heat exchange type one-stage converter and carry out one section steam reforming reaction, steam reforming reaction institute heat requirement is from the high level heat of two sections reforming gas of high temperature of secondary reformer generation in the described heat exchange type one-stage converter, this heat obtains by the indirect heat exchange between two sections reforming gas of described high temperature and the described heat exchange type one-stage converter inner reaction tube thing, and one section reforming gas that reaction generates in the described heat exchange type one-stage converter enters described secondary reformer and carries out CH ₄Degree of depth conversion reaction; Secondary reformer in described A, B two series adds the CO that the off-gas that produces in the methyl alcohol building-up process obtains through separation respectively ₂Gas is in order to regulate the H of the two sections reforming gas of high temperature that generate ₂The described CO of/C ratio ₂Be to reclaim from the combustion product gases of external-heat one-stage converter described in the A series, described combustion product gases is reclaiming CO ₂Before, the CO that is provided with the convection zone of described external-heat one-stage converter ₂Preheat coil, hydro carbons gas/steam preheating coil pipe, hydro carbons gas preheat coil, oxygen preheat coil pipe and the heat exchange of combustion air preheat coil enter stack gas after self temperature reduces and reclaim CO ₂Device;

2), after two sections reforming gas of high temperature of generating of the secondary reformer described in the B series offer described heat exchange type one-stage converter with heat, after reducing temperature, heat recovery equipment enters the CO tripping device again, cutting out partial CO; After two sections reforming gas of high temperature that secondary reformer described in the A series generates offer described heat exchange type one-stage converter with heat, through heat recovery equipment, mixes with the tail gas behind two sections reforming gas separate part CO of the described secondary reformer of B series, be used as synthetic gas; The H that the off-gas that produces in the synthesis gas preparation methanol process obtains through separation ₂, rich CO ₂Gas and tail gas turn back in the synthesis gas preparation process, realize resource circulation utilization.

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