A process and apparatus for the conversion of hydrocarbons

Abstract

The application discloses a kind of hydrocarbon conversion method and device, belong to coal bed gas technical field.The present application solves the problem that coal gas layer cannot fully play its resource value in prior art, including the following steps: step S1: raw gas is subjected to oxygen removal process in one-stage conversion, and raw gas A is obtained;Step S2: the obtained raw gas A is boosted, and raw gas B is obtained;Step S3: raw gas B is subjected to desulfurization, and desulfurized gas C is obtained;Step S4: desulfurized gas C is transported into the furnace tube of two-stage conversion furnace for hydrocarbon steam conversion reaction, and conversion gas D is obtained;Step S5: conversion gas D is transported into three-stage conversion furnace, and deep conversion reaction of methane is carried out, and conversion gas E is obtained;Step S6: after heat recovery, synthesis gas is obtained from conversion gas E.The present application provides three-stage conversion technology of hydrocarbon in view of the characteristics of high oxygen and nitrogen content in coal bed gas, solves the safe utilization problem of oxygen contained in coal bed gas and the problem of greenhouse gas emission polluting the environment.

Description

A method and apparatus for hydrocarbon conversion Technical Field

[0001] This invention belongs to the field of coalbed methane technology, specifically relating to a method and apparatus for hydrocarbon conversion. Background Technology

[0002] Coalbed methane, also known as coal seam gas, is a mixture of methane, nitrogen, oxygen, and carbon dioxide escaping from coal and surrounding rocks. A typical composition of coalbed methane is 38% methane, 50% nitrogen, 12% oxygen, and small amounts of carbon dioxide and sulfides. The explosive limits of coalbed methane are approximately 14%-40%. Because coalbed methane is close to its lower explosive limit, explosions frequently occur during coal mining. The safe utilization of coalbed methane has always been a challenge, and the greenhouse effect caused by the on-site release of low-concentration coalbed methane also has a negative impact on the climate.

[0003] Although coalbed methane is a usable energy source, its availability is limited by geographical constraints, dispersed gas sources, and poor safety, and is subject to technological limitations. For example, patent CN 1789111A discloses a process for autothermal conversion of oxygen in coalbed methane layers with moderate methane content to produce hydrogen. However, before deoxygenation, the oxygen content of the coalbed methane in the desulfurization unit is generally no more than 1%, otherwise the desulfurization unit will overheat severely and fail to operate, making it unsuitable for treating gases with oxygen concentrations of 1-15%. Patent CN 101613627B describes a catalytic deoxygenation process for oxygen-containing coalbed methane, solving the safety hazards caused by the presence of O2 during coalbed methane liquefaction, storage, and transportation. It can be applied to the catalytic deoxygenation of oxygen-containing coalbed methane and other oxygen-containing gases, but it uses a precious metal catalyst, resulting in very high costs. Therefore, currently, coalbed methane is mostly delivered to end users for combustion via pipelines or concentrated with methane through physical methods, failing to fully realize its resource value. Summary of the Invention

[0004] To address the problems in the prior art, the present invention provides a method and apparatus for hydrocarbon conversion.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for hydrocarbon conversion includes the following steps:

[0007] Step S1: First stage conversion: The raw gas undergoes a combustion reaction of oxygen and hydrogen or methane in a first stage converter to remove oxygen and obtain raw gas A;

[0008] Step S2: Pressurize the cooled raw material gas A obtained in step S1 to obtain raw material gas B;

[0009] Step S3: Desulfurize the raw material gas B obtained in step S2 to obtain desulfurized gas C;

[0010] Step S4: Second-stage conversion: The desulfurized gas C obtained in step S3 is transported to the furnace tube of the second-stage conversion furnace for hydrocarbon steam conversion reaction to obtain converted gas D;

[0011] Step S5: Three-stage conversion: The converted gas D obtained in step S4 is sent to a three-stage conversion furnace to carry out a deep conversion reaction of methane, and converted gas E is obtained.

[0012] Step S6: The converted gas E obtained in step S5 is subjected to heat recovery to obtain syngas.

[0013] Preferably, when the raw gas is transported to a primary converter for combustion reaction of oxygen with hydrogen or methane, the reaction pressure is atmospheric pressure to 1.0 MPaG and the temperature is 600-1300℃. The primary converter is a non-catalytic partial oxidation furnace without a catalyst.

[0014] Preferably, the pressure boosting device used in step S2 is a reciprocating compressor or a centrifugal compressor, and the boosted pressure is 1.0-4.0 MPaG.

[0015] After adopting this technical solution, the booster device is a reciprocating compressor or a centrifugal compressor. The purpose of boosting the pressure is to reduce the size of the equipment, reduce investment and floor space, and facilitate transportation.

[0016] Preferably, the desulfurization device used in step S2 removes the total sulfur in the gas to below 0.2 ppm.

[0017] Preferably, in step S4, the second-stage converter is a heat exchange converter and / or a chamber converter, the temperature of the converted gas D is 600-900℃, and the second-stage converter adopts fuel combustion heating and / or non-fuel combustion heating.

[0018] Preferably, in step S5, the three-stage conversion furnace is a partial oxidation furnace containing a catalyst, and the temperature of the conversion gas E is 800-1000℃.

[0019] Preferably, the raw material gas in step S1 is a gaseous hydrocarbon, including hydrocarbon-containing gases such as natural gas, coke oven gas, and coalbed methane.

[0020] A hydrocarbon conversion device includes a first-stage converter, a pressurization unit, a desulfurization unit, a second-stage converter, a third-stage converter, a heat recovery unit, and a syngas storage unit connected in sequence.

[0021] Preferably, the first-stage converter is not filled with a reaction catalyst, and is provided with a long inlet for introducing high-temperature gas, and also has multiple raw material gas inlets for introducing raw material gas; the second-stage converter is a box-type converter or a heat exchange converter, and the conversion tube of the second-stage converter is filled with a reaction catalyst; the third-stage converter is a partial oxidation furnace filled with a catalyst, the partial oxidation furnace is a self-heating reactor, and a high-temperature mixer is provided inside the third-stage converter, the high-temperature mixer being connected to an oxygen-containing gas input pipeline.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. This invention significantly improves the safety of secondary transportation and conversion of coalbed methane by adding a conversion process to treat the oxygen in the coalbed methane, thereby reducing carbon emissions, mitigating the greenhouse effect, and solving the problem of pollution from mine entrance emissions.

[0024] 2. The first-stage conversion process of the present invention adopts a non-catalytic partial oxidation process, which does not require additional oxygen, and steam can be added or not added at all, and the coalbed methane can be converted and treated on-site.

[0025] 3. The two-stage conversion process of the present invention can adopt the traditional pressurized steam conversion process, the heat exchange conversion process, or a parallel or series conversion process combining the pressurized steam conversion process and the heat exchange conversion process.

[0026] 4. The hydrocarbon conversion method described in this invention has the advantages of simple structure, easy manufacturing and maintenance, and can realize the joint production of hydrogen, methanol, ammonia, acetic acid, etc., realize resource recycling, and thus greatly reduce various consumption indicators.

[0027] 5. The three-stage conversion process of the present invention adopts a self-heating catalytic partial oxidation process, adding pure oxygen or air or oxygen-enriched / nitrogen-enriched air to deeply convert alkanes such as methane and improve the utilization rate of raw materials. Attached Figure Description

[0028] Figure 1 is a process flow diagram of the present invention;

[0029] Figure 2 is a schematic diagram of the device connection mechanism of the present invention;

[0030] Among them, 1-first stage converter, 2-pressurization device, 3-desulfurization device, 4-second stage converter, 5-third stage converter, 6-heat recovery device, 7-syngas storage device. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0032] In the description of the embodiments of this application, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] As shown in Figures 1 and 2, a hydrocarbon conversion method is disclosed. This method utilizes a hydrocarbon conversion device, which comprises, in sequence, a primary converter 1, a booster unit 2, a desulfurization unit 3, a secondary converter 4, a tertiary converter 5, a heat recovery unit 6, and a syngas storage unit 7. The outlet of the primary converter 1 is connected to the inlet of the booster unit 2; the inlet of the desulfurization unit 3 is connected to the outlet of the booster unit 2; the inlet of the secondary converter 4 is connected to the outlet of the desulfurization unit 3; the inlet of the tertiary converter 5 is connected to the outlet of the secondary converter 4; the inlet of the heat recovery unit 6 is connected to the outlet of the tertiary converter 5; and the outlet of the heat recovery unit 6 is connected to the syngas storage unit.

[0034] In this embodiment, the heat recovery device 6 is a heat exchanger or separator that can recover the waste heat of the gas and cool it down.

[0035] In this embodiment, the first-stage converter 1 is not filled with a reaction catalyst. The first-stage converter 1 is provided with a long inlet for introducing high-temperature gas, and the first-stage converter 1 is also provided with multiple raw material gas inlets for introducing raw material gas. The second-stage converter 4 is a box-type converter and / or a heat exchange converter, and the conversion tube of the second-stage converter 4 is filled with a reaction catalyst. The third-stage converter 5 is a partial oxidation furnace filled with a catalyst. The partial oxidation furnace is a self-heating reactor. The third-stage converter 5 is provided with a high-temperature mixer inside, and the high-temperature mixer is connected to an oxygen-containing gas input pipe.

[0036] In this embodiment, the booster device is a reciprocating compressor, and the boosted pressure is 3 MPaG.

[0037] In this embodiment, the desulfurization device 3 uses dry desulfurization, specifically by using a desulfurization catalyst to remove the total sulfur in the gas to below 0.2 ppm.

[0038] The hydrocarbon conversion method includes the following steps:

[0039] Step S1: First stage conversion: Coalbed methane is transported to the first stage converter 1 and high-temperature gas is introduced to carry out the combustion reaction of oxygen with hydrogen or methane. The reaction pressure is atmospheric pressure and the temperature is 800℃. No additional oxygen is needed and no steam is supplied. The oxygen is removed to obtain raw material gas A.

[0040] Step S2: The raw material gas A obtained in step S1, which is cooled to 40°C, is sent to the booster device 2 for pressurization to obtain raw material gas B;

[0041] Step S3: The raw material gas B obtained in step S2 is fed into the desulfurization unit for desulfurization to obtain desulfurized gas C;

[0042] Step S4: Second-stage conversion: The desulfurized gas C obtained in step S3 is transported to the catalyst bed of the conversion tube of the second-stage conversion furnace 4 to carry out hydrocarbon steam conversion reaction, and converted gas D is obtained at a temperature of 650℃, with a hydrocarbon conversion rate of about 30% to 80%.

[0043] Step S5: Three-stage conversion: The converted gas D obtained in step S4 is transported to the three-stage conversion furnace 5 for deep conversion of methane to obtain converted gas E. The temperature of converted gas E is 850℃, and the hydrocarbon conversion rate reaches about 98%.

[0044] Step S6: The converted gas E obtained in step S5 is sent to a heat recovery device for heat recovery to obtain syngas.

[0045] In this invention, high-temperature gas enters the first-stage reformer 1 to provide ignition conditions for the oxygen reaction in the coalbed methane within the first-stage reformer 1, thereby achieving the purpose of oxygen removal. When the second-stage reformer 4 adopts a box-type reformer, the fuel gas enters the outside of the radiant section reforming tube of the second-stage reformer 4 for combustion, and the heat released by combustion provides heat for the hydrocarbon conversion reaction within the reforming tube. When the second-stage reformer 4 adopts a heat exchange reformer, the heat required for the hydrocarbon conversion reaction within the reforming tube of the heat exchange reformer is provided by the high-temperature reforming gas E at the outlet of the third-stage reformer 5, thereby saving fuel gas consumption. Oxygen-containing gas enters the third-stage reformer 5, and the oxygen reacts with the hydrogen and methane in the raw material gas D at the inlet of the third-stage reformer 5 to release a large amount of heat, providing the heat required for the deep hydrocarbon conversion reaction, thereby reducing the methane content in the reforming gas E at the outlet of the third-stage reformer 5 to below 0.5% (volume, dry basis).

[0046] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A method for hydrocarbon conversion, characterized in that: Including the following Steps: Step S1: First-stage conversion: Coalbed methane undergoes a combustion reaction of oxygen and hydrogen or methane in a first-stage conversion furnace (1) to remove oxygen and obtain raw material gas A; The specific steps of the first-stage conversion deoxygenation process are as follows: When the raw material gas is transported to the first-stage conversion furnace (1) for a combustion reaction of oxygen and hydrogen or methane, the reaction pressure is atmospheric pressure to 1.0 MPaG and the temperature is 600-1300℃. The first-stage conversion furnace (1) is a non-catalytic partial oxidation furnace without a catalyst; Step S2: Cooling the step S1 The obtained raw material gas A is pressurized to obtain raw material gas B; Step S3: The raw material gas B obtained in step S2 is desulfurized to obtain desulfurized gas C; Step S4: Second-stage conversion: The desulfurized gas C obtained in step S3 is transported to the furnace tube of the second-stage conversion furnace (4) for hydrocarbon steam conversion reaction to obtain converted gas D; The second-stage conversion furnace (4) is a heat exchange conversion furnace or a box-type conversion furnace, and the temperature of the converted gas D is 600-900℃. The second-stage conversion furnace (4) adopts fuel combustion heating and / or non-fuel combustion heating method; Step S5: Third-stage conversion: The converted gas D obtained in step S4 is transported to the third-stage conversion furnace (5) for deep conversion reaction of methane to obtain converted gas E; The third-stage conversion furnace (5) is a partial oxidation furnace containing a catalyst, and the temperature of the converted gas E is 800-1000℃; Step S6: The converted gas E obtained in step S5 is heat recovered to obtain synthesis gas.

2. The hydrocarbon conversion method according to claim 1, characterized in that: The pressure boosting device used in step S2 is a reciprocating compressor or a centrifugal compressor, and the boosted pressure is 1.0-4.0 MPaG.

3. The hydrocarbon conversion method according to claim 1, characterized in that: In step S2, desulfurization is carried out using a dry method, specifically by using a desulfurization catalyst to remove the total sulfur in the gas to below 0.2 ppm.

4. A hydrocarbon conversion apparatus based on the hydrocarbon conversion method according to any one of claims 1-3, characterized in that: It includes a first-stage converter (1), a booster (2), a desulfurization unit (3), a second-stage converter (4), a third-stage converter (5), a heat recovery unit (6), and a syngas storage unit (7), which are connected in sequence.

5. A hydrocarbon conversion device according to claim 4, characterized in that: The first-stage converter (1) is not filled with a reaction catalyst. The first-stage converter (1) is provided with a long inlet for introducing high-temperature gas. The first-stage converter (1) is also provided with multiple raw material gas inlets for introducing raw material gas. The second-stage converter (4) is a box-type converter and / or a heat exchange converter. The conversion tube of the second-stage converter (4) is filled with a reaction catalyst. The third-stage converter (5) is a partial oxidation furnace filled with a catalyst. The partial oxidation furnace is a self-heating reactor. The third-stage converter (5) is provided with a high-temperature mixer inside. The high-temperature mixer is connected to an oxygen-containing gas input pipe.

Images