阅读说明：本技术 煤气化方法、煤气化炉、煤气化系统和煤气化合成氨系统 (Coal gasification method, coal gasification furnace, coal gasification system, and coal gasification synthetic ammonia system ) 是由 鲁思达 谢星 姜楠 陈良奇 孟庆珂 张�林 张步超 于 2021-07-30 设计创作，主要内容包括：本发明公开一种煤气化方法、煤气化炉、煤气化系统和煤气化合成氨系统。煤气化方法在煤气化炉中进行,煤气化炉包括气化腔室,气化腔室在高度方向上依次区分为上部区域、中部区域和下部区域,方法包括：将第一气化剂引入气化腔室的下部区域,与经过气化腔室的上部区域和中部区域的气化处理后的煤料进行燃烧反应；将第二气化剂引入气化腔室的中部区域参与气化反应,以产生煤气。(The invention discloses a coal gasification method, a coal gasification furnace, a coal gasification system and a coal gasification synthetic ammonia system. The coal gasification method is carried out in a coal gasification furnace, the coal gasification furnace comprises a gasification chamber, and the gasification chamber is sequentially divided into an upper region, a middle region and a lower region in the height direction, and the method comprises the following steps: introducing a first gasification agent into the lower region of the gasification chamber, and carrying out combustion reaction on the first gasification agent and the coal material subjected to gasification treatment in the upper region and the middle region of the gasification chamber; a second gasifying agent is introduced into the middle region of the gasification chamber to participate in the gasification reaction to produce coal gas.)

1. A method of coal gasification, the method being carried out in a coal gasifier comprising a gasification chamber which is subdivided in height direction into an upper zone, a middle zone and a lower zone, the method comprising:

introducing a first gasification agent into the lower region of the gasification chamber, and carrying out combustion reaction on the first gasification agent and the coal material subjected to gasification treatment in the upper region and the middle region of the gasification chamber;

introducing a second gasifying agent into the middle area of the gasification chamber to participate in gasification reaction so as to generate coal gas.

2. The method of claim 1, wherein the gasification chamber has a temperature change from a reduced temperature to an increased temperature in a section from the introduction location of the first gasification agent to the introduction location of the second gasification agent, wherein the minimum temperature of the section is 850 ℃ to 1200 ℃, or 900 ℃ to 950 ℃.

3. The method according to claim 1 or 2, characterized in that the temperature of the gasification chamber at the location of introduction of the second gasification agent is 1100 ℃ to 1300 ℃, or 1200 ℃ to 1300 ℃.

4. The method of claim 1, wherein a gas outlet of the coal gasifier is located in an upper region of the gasification chamber, wherein the temperature of the gasification chamber corresponding to the gas outlet is 850 ℃ to 950 ℃, or 870 ℃ to 920 ℃.

5. The method of claim 1, wherein a ratio of a volume flow rate of oxygen introduced into the gasification chamber by the first gasifying agent to a volume flow rate of oxygen introduced into the gasification chamber by the second gasifying agent is 9:1 to 5:5, or 7:3 to 6: 4.

6. The method of any one of claims 1 to 5, wherein the first gasifying agent comprises oxygen and water vapour, wherein the mass to volume ratio of water vapour to oxygen is 0.8kg/Nm³～1.2kg/Nm³Or 0.95kg/Nm³～1.05kg/Nm³(ii) a And/or the presence of a gas in the gas,

the second gasifying agent comprises oxygen and water vapor, wherein the mass volume ratio of the water vapor to the oxygen is 2.0kg/Nm³～5.0kg/Nm³。

7. The method according to claim 6, wherein the ash melting point of the raw material coal is 1400 ℃ or lower, and the mass-to-volume ratio of water vapor to oxygen in the second gasifying agent is 3.5kg/Nm³～5.0kg/Nm³(ii) a Alternatively, the first and second electrodes may be,

the ash melting point of the raw material coal is more than 1400 ℃, and the mass volume ratio of the water vapor to the oxygen in the second gasification agent is 2.5kg/Nm³～3.5kg/Nm³。

8. The method of claim 1, wherein the pressure of the gasification chamber is 2.0 to 6.0MPa, or 2.5 to 4.0 MPa.

9. The method of claim 1, wherein the coal gasifier is a slagging liquid fixed bed gasifier.

10. The utility model provides a coal gasifier, includes the furnace body, the furnace body is equipped with gasification chamber, is located the coal feeding mouth at top and is located the row cinder notch of bottom, the furnace body is regional, middle part region and lower part region in the direction of height distinguish in proper order the lower part region of furnace body is equipped with first gasification agent and introduces the mouth the middle part region of furnace body is equipped with second gasification agent and introduces the mouth, first gasification agent entry with second gasification agent entry respectively with gasification chamber intercommunication.

11. The coal gasifier according to claim 10, wherein a height of the furnace body is denoted by H, and a height at which the second gasifying agent introduction port is provided is denoted by H, wherein: h is more than or equal to 0.3H and less than or equal to 0.6H, or H is more than or equal to 0.45H and less than or equal to 0.5H.

12. The coal gasifier according to claim 10, wherein 4 to 6 first gasifying agent introduction ports are provided in a lower region of the furnace body at intervals in a circumferential direction of the furnace body;

and 2-6 second gasifying agent introducing openings are formed in the middle area of the furnace body at intervals along the circumferential direction of the furnace body.

13. A coal gasification system comprising:

a coal gasification furnace according to any one of claims 10 to 12 for performing a coal gasification process;

and the gasification agent supply assembly is used for supplying a first gasification agent to the gasification chamber of the coal gasification furnace through the first gasification agent introduction port so as to enable the first gasification agent to perform combustion reaction with the coal material subjected to gasification treatment in the upper region and the middle region of the furnace body, and supplying a second gasification agent to the gasification chamber of the coal gasification furnace through the second gasification agent introduction port so as to enable the second gasification agent to participate in the gasification reaction so as to generate coal gas.

14. The system of claim 13, further comprising:

the dust removal device is used for removing dust from the coal gas of the coal gasification furnace;

and the waste heat recovery device is used for recovering waste heat of the coal gas from the dust removal device.

15. The system of claim 14, wherein the dust removal device comprises a venturi scrubber, the system further comprising:

the gas-liquid separation device is used for carrying out gas-liquid separation on the coal gas from the waste heat recovery device;

and the waste liquid treatment device is used for purifying the waste liquid from the waste heat recovery device and the gas-liquid separation device and sending the purified liquid to the Venturi scrubber for cyclic utilization.

16. A coal gasification ammonia synthesis system comprising:

a gas-making unit comprising the coal gasification system of any one of claims 13-15;

a shift unit for receiving the syngas from the gas-making unit and shift-processing the syngas to shift CO to CO₂Sending out the transformation gas;

a decarbonization unit for decarbonizing the shift gas from the shift unit to obtain decarbonized gas;

a double-refining unit for double-refining the decarbonized gas from the decarbonization unit to obtain a raw material gas;

and the synthesis ammonia unit is used for receiving the feed gas from the double-methyl refining unit and synthesizing ammonia by using the feed gas.

Technical Field

The invention belongs to the technical field of coal chemical industry, and particularly relates to a coal gasification method, a coal gasification furnace, a coal gasification system and a coal gasification synthetic ammonia system.

Background

Coal, as a fossil fuel, is one of the indispensable energy sources for people to produce and live at present and even for a long time in the future. If coal is directly combusted, a large amount of resources are wasted, and SO is discharged₂、NO_xAnd harmful gases such as CO, etc., causing environmental pollution. Therefore, promoting clean utilization of coal has become a necessary choice for industry development.

Coal gasification is one of the important ways for clean utilization of coal. The existing coal gasification technology is that coal is added into a coal gasification furnace, and the coal is converted into coal gas under the condition of pressurization and existence of gasification agents. The coal gas contains effective gases (CO and H)₂) Also contains more CH₄. Due to CH in the coal gas₄The content is high, which has adverse effect on the subsequent chemical synthesis for synthesizing ammonia and the like. CH (CH)₄Inert gases, CH in coal gases, in processes using coal gases as raw materials, e.g. for ammonia synthesis₄Too high a content tends to increase the compressor power consumption in the process system and also to cause too much purge gas emissions, thus seriously affecting the economics of ammonia synthesis. Therefore, the development of a low-methane coal gasification process is of great significance.

Disclosure of Invention

The present invention in a first aspect provides a coal gasification method performed in a coal gasification furnace including a gasification chamber, the gasification chamber being divided into an upper region, a middle region, and a lower region in the height direction in this order, the method comprising: introducing a first gasification agent into the lower region of the gasification chamber, and carrying out combustion reaction on the first gasification agent and the coal material subjected to gasification treatment in the upper region and the middle region of the gasification chamber; a second gasifying agent is introduced into the middle region of the gasification chamber to participate in the gasification reaction to produce coal gas.

The invention provides a coal gasifier in a second aspect, which comprises a furnace body, wherein the furnace body is provided with a gasification chamber, a coal inlet positioned at the top and a slag discharge port positioned at the bottom, and the furnace body is sequentially divided into an upper area, a middle area and a lower area in the height direction, wherein the lower area of the furnace body is provided with a first gasifying agent inlet, the middle area of the furnace body is provided with a second gasifying agent inlet, and the first gasifying agent inlet and the second gasifying agent inlet are respectively communicated with the gasification chamber.

In a third aspect, the present invention provides a coal gasification system comprising: the coal gasification furnace is used for performing coal gasification treatment; and the gasifying agent supply assembly is used for supplying a first gasifying agent to the gasifying chamber of the coal gasifying furnace through the first gasifying agent introducing port so that the first gasifying agent and the coal material subjected to the gasifying treatment in the upper region and the middle region of the furnace body are subjected to a combustion reaction, and supplying a second gasifying agent to the gasifying chamber of the coal gasifying furnace through the second gasifying agent introducing port so that the second gasifying agent participates in the gasification reaction to generate coal gas.

In a fourth aspect, the present invention provides a coal gasification ammonia synthesis system, comprising: a gas-making unit comprising a coal gasification system according to the invention; a shift unit for receiving the synthesis gas from the gas-making unit and performing shift processing on the synthesis gas to shift CO into CO₂Sending out the transformation gas; a decarbonization unit for decarbonizing the shift gas from the shift unit to obtain decarbonized gas; a double-refining unit for double-refining the decarbonized gas from the decarbonization unit to obtain a raw material gas; and the ammonia synthesis unit is used for receiving the raw material gas from the double-methyl refining unit and synthesizing ammonia by using the raw material gas.

The invention is nowThe gasification agent is introduced into the middle area on the basis of the gasification agent introduced into the coal gasifier from the lower area, so that the generation of CH in the coal hydropyrolysis reaction can be reduced₄And also promote CH in the furnace₄So as to reduce CH of the coal gas₄And (4) content. Low CH₄The coal gasification product with the content can be used as raw material gas for synthesizing ammonia, and is beneficial to reducing the purge gas amount and energy consumption of an ammonia synthesis system. Furthermore, the scheme of the invention can also promote the cracking of tar generated in the coal gasification process, thereby reducing the tar content of coal gas and further improving the effective gas (CO and H)₂) Ratio of occupation.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a coal gasifier according to an embodiment of the present invention.

Fig. 2 is a flow chart of a coal gasification system according to an embodiment of the present invention.

FIG. 3 is a flow diagram of a coal gasification ammonia synthesis system according to an embodiment of the present invention.

FIG. 4 is a flow diagram of a coal gasification ammonia synthesis system according to another embodiment of the present invention.

Fig. 5 is a furnace temperature profile of the coal gasification furnace of example 1.

Fig. 6 is a furnace temperature profile of the coal gasification furnace of example 2.

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present invention more clear, features of various aspects and exemplary embodiments of the present invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. In the drawings and the following description, at least some well-known structures and techniques have not been shown in detail in order to avoid unnecessarily obscuring the present invention; also, the dimensions of some of the structures may be exaggerated for clarity. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In the description of the present invention, it is to be noted that, unless otherwise specified, "above" and "below" are inclusive of the present numbers; "plural" and "several" mean two or more; the terms "upper," "lower," "left," "right," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated for convenience in describing the invention and to simplify description, but do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The directional terms appearing in the following description are intended to be illustrative in all directions, and are not intended to limit the specific construction of embodiments of the present invention. In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "mounted" and "connected" are to be interpreted broadly, e.g., as either a fixed connection, a removable connection, or an integral connection; can be directly connected or indirectly connected. The specific meaning of the above terms in the present invention can be understood as appropriate to those of ordinary skill in the art.

The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The following description more particularly exemplifies illustrative embodiments. At various points throughout this application, guidance is provided through a list of embodiments that can be used in various combinations. In each instance, the list is merely a representative group and should not be construed as exhaustive.

As one of the important approaches for clean utilization of coal, raw material coal can be sequentially subjected to several stages of drying, dry distillation, gasification and combustion in a coal gasification furnace in the presence of pressurization and a gasification agent to be converted into coal gas. After entering the gasification chamber from a coal inlet at the top of the coal gasifier, the raw coal is firstly dried. In the drying zone, the raw material coal is in countercurrent contact with high-temperature coal gas from bottom to top, the temperature of the coal gas is reduced while the temperature of the coal gas is increased, and thus moisture (such as free water and/or bound water) carried by the raw material coal is removed. After the coal is dried, the coal continuously moves downwards to a carbonization area, is heated by high-temperature coal gas in the carbonization area, and carries out low-temperature carbonization and hydropyrolysis reaction of the coal to produce coke (or semicoke), coal tar and carbonization coal gas (including CO and H)₂、CO₂、CH₄And other hydrocarbons, etc.). The coke (or semi-coke) continuously moves downwards to a gasification zone for further heating, and a series of oxidation-reduction reactions occur to generate CO and H₂、CO₂、CH₄Crude gas and C-containing solids residue. The C-containing solid residue moves downwards to a combustion zone and contacts with a gasifying agent to generate a combustion reaction to generate CO and CO₂Etc., while generating a large amount of heat. The gas carries heat upwards, thereby providing the required heat for the gasification process. The residual slag is discharged out of the gasification furnace as solid slag or liquid slag. The liquid slag can be chilled and then crushed into glassy slag for resource recycling.

Because the gasification agent is introduced into the lower region of the gasification chamber in the existing coal gasifier, the temperature in the gasifier is gradually reduced from a combustion region to a drying region, wherein the interval of a dry distillation region is very long, and the interval temperature is 250-800 ℃. A large amount of CH is generated in this interval₄This causes CH of the gas discharged from the gas outlet of the gasification furnace₄The content is higher. According to the different types of raw coal, CH of coal gas₄The content is 4-9%. Generating CH₄The main reaction equation of (a) is:

coal → coke + CO + H₂+CH₄+ Tar (1)

The reaction (1) depends on the content of volatile matter in the gasified coal, and the higher the content of volatile matter is, the CH generated in the reaction (1)₄The higher the CH formed in reaction (1)₄Cannot be suppressed by the operation process. Reaction (2) is an exothermic reversible reaction and is severely affected by chemical equilibrium. The reaction temperature is a major factor affecting the equilibrium constant of the reaction (2). The component content and the balance constant lgK of the equilibrium at different temperatures are measured by experiments_pSee table below:

as can be seen from the above table, CH is present due to the temperature in the retort zone < 800 deg.C₄The amount of production is large. But when the temperature is above 800 ℃, CH₄Generation is significantly inhibited, and CH₄Can be converted to further reduce.

Based on the improvement, the original coal gasification furnace and the coal gasification process are improved, and the gasification agent is introduced into the middle area of the gasification chamber on the basis of the existing gasification agent introduced from the lower area of the gasification chamber. The gasification agent introduced from the middle region of the gasification chamber will be mixed with the gas (e.g., CO and H)₂) Etc., and a large amount of heat is released. The created high-temperature (for example, more than or equal to 800 ℃) environment can inhibit CH generated by coal hydropyrolysis reaction₄Amount of CH produced by dry distillation of coal₄Conversion occurs, thereby greatly reducing CH of the gas product₄And (4) content.

Next, a coal gasification method according to the present invention will be described. The coal gasification method is carried out in a coal gasification furnace, the coal gasification furnace comprises a gasification chamber, and the gasification chamber is sequentially divided into an upper area, a middle area and a lower area in the height direction, and the method comprises the following steps: introducing a first gasification agent into the lower region of the gasification chamber, and carrying out combustion reaction on the first gasification agent and the coal material subjected to gasification treatment in the upper region and the middle region of the gasification chamber; a second gasifying agent is introduced into the middle region of the gasification chamber to participate in the gasification reaction to produce coal gas.

The coal gasification furnace can adopt a fixed bed gasification furnace. The fixed bed gasification furnace usually adopts lump coal as raw material, and reacts with a gasification agent under pressurization to prepare synthesis gas, and has the advantage of wide raw material adaptability. For example, the raw material coal may be selected from anthracite, bituminous coal, lignite, and the like. The coal gasification furnace can be a solid slag-off fixed bed gasification furnace or a liquid slag-off fixed bed gasification furnace. Preferably, the coal gasification furnace is a slag tapping fixed bed gasification furnace.

The coal gasification furnace comprises a furnace body, wherein the furnace body is provided with a gasification chamber, a coal inlet positioned at the top, a slag discharge port positioned at the bottom and a coal gas outlet positioned on the side wall. And a first gasifying agent inlet is arranged at the lower part of the furnace body, a second gasifying agent inlet is arranged at the middle part of the furnace body, and the first gasifying agent inlet and the second gasifying agent inlet are respectively communicated with the gasifying chamber.

The raw material coal is fed into the gasification chamber through a coal inlet, and a first gasification agent is introduced into the lower region of the gasification chamber through a first gasification agent introduction port, and a second gasification agent is introduced into the middle region of the gasification chamber through a second gasification agent introduction port. The residual C-containing solid residue after the raw material coal is dried, dry distilled at low temperature, hydropyrolysis and gasification reaction of coke (or semi-coke) is contacted with a first gasification agent in the lower area to carry out combustion reaction so as to generate heat required by a series of reactions in the furnace, and simultaneously, reductive gases such as CO and the like are generated for the reaction. In the middle region of the gasification chamber, the second gasification agent is mixed with CO and H₂The heat generated by the reaction creates the inhibited CH₄Generation and promotion of CH₄High temperature environment of conversion, ultimately producing low CH₄Coal gas with high content. The high-temperature environment can also promote the cracking of tar generated in the coal gasification process, thereby reducing the tar content of coal gas and further improving the effective gas (CO and H)₂) Ratio of occupation.

In some embodiments, the introduction of the first gasification agent is to the second gasificationThe gasification chamber is subjected to a temperature change of decreasing temperature and increasing temperature in the interval of introduction positions of the agent, wherein the minimum temperature in the interval is 850-1200 ℃, preferably 850-1000 ℃, and more preferably 900-950 ℃. The lowest temperature in the interval from the introduction position of the first gasifying agent to the introduction position of the second gasifying agent is in a proper range, so that the temperature in the furnace below and above the introduction position of the second gasifying agent can be controlled to inhibit CH₄Generation and promotion of CH₄High temperature of conversion, thereby reducing CH of coal gas₄And (4) content. In addition, the temperature in the furnace can also promote the cracking conversion of tar in the coal gas, so that the tar content of the coal gas is reduced. Therefore, the obtained coal gas can obtain higher effective gas ratio.

In some embodiments, the temperature of the gasification chamber at the location of introduction of the second gasification agent is 1100 ℃ to 1300 ℃, preferably 1200 ℃ to 1300 ℃. The temperature of the gasification chamber corresponding to the introduction position of the second gasification agent is higher, which is beneficial to increasing the temperature in the furnace in the area below and above the introduction position of the second gasification agent, thereby being capable of inhibiting CH₄Generation and promotion of CH₄Conversion to obtain low CH₄Coal gas with high content. Meanwhile, the cracking and conversion of tar in the coal gas can be promoted, and the tar content of the coal gas is reduced. The temperature of the gasification chamber corresponding to the introduction position of the second gasification agent is in a proper range, so that the coal material in the region can be prevented from melting, the stable operation of the gasification process in the furnace is ensured, and the coal gas with high effective gas ratio is obtained.

In some embodiments, the gas outlet of the coal gasifier is located in an upper region of the gasification chamber, wherein the temperature of the gasification chamber corresponding to the gas outlet is 850 ℃ to 950 ℃, preferably 870 ℃ to 920 ℃. The temperature of the gasification chamber above the introduction position corresponding to the second gasification agent is higher, which is beneficial to inhibiting CH₄Generation and promotion of CH₄Conversion is facilitated, and tar cracking conversion is facilitated, so that CH of coal gas is reduced₄Content and tar content.

The reaction and the temperature in the furnace can be controlled by adjusting the introduction position of the second gasifying agent and the composition of the first gasifying agent and the second gasifying agent, so as to realize the reduction of CH of coal gas₄Content and tar contentAmount of the compound (A).

In some embodiments, the ratio of the volume flow rate of the oxygen introduced into the gasification chamber by the first gasifying agent to the volume flow rate of the oxygen introduced into the gasification chamber by the second gasifying agent is 9:1 to 5:5, preferably 7:3 to 6: 4. The ratio of the oxygen volume flow of the first gasifying agent to the oxygen volume flow of the second gasifying agent is in a proper range, which is beneficial to reducing CH of coal gas₄The content of the coal gas is high, and the coal gas has high effective gas ratio. The volume flow ratio can be controlled by adjusting one or more of the steam-oxygen ratio of the first gasifying agent, the flow rate of the first gasifying agent, the steam-oxygen ratio of the second gasifying agent, and the flow rate of the second gasifying agent.

In some embodiments, the first gasifying agent comprises oxygen and water vapor. Optionally, the first gasifying agent is a mixture of oxygen and water vapor. Further optionally, the water vapour is superheated water vapour. The mass to volume ratio of water vapor to oxygen of the first gasifying agent may optionally be 0.8kg/Nm³～1.2kg/Nm³Optionally 0.9kg/Nm³～1.1kg/Nm³Or 0.95kg/Nm³～1.05kg/Nm³. The mass-to-volume ratio of water vapor to oxygen (which may be simply referred to as the vapor-to-oxygen ratio) refers to the mass of water vapor in kg to oxygen in Nm³Volume ratio in kg/Nm³。Nm³Is a standard cubic meter and represents the amount of gas in 1 cubic meter at a pressure of one standard atmosphere (101.325kPa), a temperature of 0c, and a relative humidity of 0%.

In some embodiments, the second gasifying agent comprises oxygen and water vapor. Optionally, the second gasifying agent is a mixed gas of oxygen and water vapor. Further optionally, the water vapour is superheated water vapour. The steam-oxygen ratio of the second gasifying agent is 2.0kg/Nm³～5.0kg/Nm³. The steam-oxygen ratio of the second gasifying agent can be selected and adjusted according to the type of the raw material coal on the premise of ensuring that the coal material at the position where the second gasifying agent is introduced is not burnt and melted. The smaller the steam-oxygen ratio of the second gasifying agent is, the CH of the coal gas₄The lower the content.

Alternatively, coals with high ash fusion points can be used with smaller secondary steam to oxygen ratios. As an example, the ash melting point of the raw material coal is more than 1400 ℃, and the water vapor is generated in the second gasification agentThe mass volume ratio of gas to oxygen is 2.5kg/Nm³～3.5kg/Nm³。

Alternatively, coals with lower ash fusion points may employ larger secondary steam to oxygen ratios. As an example, the ash melting point of the raw material coal is 1400 ℃ or less, and the steam-oxygen ratio of the second gasifying agent is 3.0kg/Nm³～5.0kg/Nm³。

Coal gasification is typically carried out under pressurized conditions. In some embodiments, the pressure of the gasification chamber may be selected to be between 2.0MPa and 6.0MPa, and may be selected to be between 2.5MPa and 5MPa, between 2.5MPa and 4.5MPa, or between 2.5MPa and 4.0 MPa.

In the coal gasification furnace of the present invention, the lower region of the gasification chamber corresponds to the combustion zone. The middle region of the gasification chamber is located between the drying zone and the combustion zone. In some embodiments, the height of the furnace body is recorded as H, and the setting height of the second gasifying agent introducing port is recorded as H, wherein the following conditions can be satisfied: h is more than or equal to 0.3H and less than or equal to 0.6H. In some embodiments, 0.35H ≦ H ≦ 0.55H. In some embodiments, 0.4H ≦ H ≦ 0.5H. In some embodiments, 0.42H ≦ H ≦ 0.47H. In some embodiments, 0.45H ≦ H ≦ 0.5H.

The coal gasification method can obtain low CH₄And coal gas with tar content and high effective gas content. The main components of the coal gas are CO and H₂And contains CO₂And a small amount of CH₄And gasification products such as tar. Preferably, CO and H in the gas₂The content of (A) can reach more than 80%, more than 82%, more than 85%, even more than 88%. Preferably, CH in coal gas₄The content of (c) may be as low as 2% or less, or 1.5% or less. Preferably, the tar content in the gas can be as low as 1% or less, or 0.5% or less.

The invention also provides a coal gasifier. Fig. 1 is a schematic view of a coal gasifier as an example. Referring to fig. 1, the coal gasifier 100 according to the present invention includes a furnace body 110, the furnace body 110 includes a gasification chamber, a coal inlet located at the top, and a slag outlet located at the bottom, and the furnace body is sequentially divided into an upper region, a middle region, and a lower region in the height direction, wherein the lower region of the furnace body 110 is provided with a first gasifying agent inlet 111, the middle region of the furnace body is provided with a second gasifying agent inlet 112, and the first gasifying agent inlet 111 and the second gasifying agent inlet 112 are respectively communicated with the gasification chamber.

In some embodiments, the height of the furnace body 110 is denoted by H, and the height of the second gasifying agent introducing port 112 is denoted by H, wherein: h is more than or equal to 0.3H and less than or equal to 0.6H. In some embodiments, 0.35H ≦ H ≦ 0.55H. In some embodiments, 0.4H ≦ H ≦ 0.5H. In some embodiments, 0.42H ≦ H ≦ 0.47H. In some embodiments, 0.45H ≦ H ≦ 0.5H.

The furnace body 110 includes a cylinder 110a, and a top flange 110b and a bottom flange 110c respectively provided at both ends of the cylinder. The height H of the furnace body 110 refers to the distance from the top surface of the top flange 110b to the bottom surface of the bottom flange 110 c. The height h of the second gasifying agent introducing port 112 is a vertical distance from a horizontal line of the center of the second gasifying agent introducing port 112 to the bottom surface of the bottom flange 110 c.

In some embodiments, a plurality of second gasifying agent introducing openings 112 may be provided at intervals in the circumferential direction of the furnace body 110 in the middle region of the furnace body 110. For example, there are 2, 3, 4, 5, or 6 second gasifying agent introducing openings 112. The plurality of second gasifying agent introducing openings 112 are preferably uniformly distributed in the circumferential direction of the furnace body 110. Thus being beneficial to the uniformity of the radial temperature field and the flow field in the furnace.

A second gasifying agent nozzle 120 may be provided to the second gasifying agent introducing port 112. A second gasification agent is provided to the gasification chamber through a second gasification agent nozzle 120. Preferably, the second gasifying agent nozzles 113 are obliquely arranged from the coal inlet to the slag outlet, wherein the included angle between the second gasifying agent nozzles 120 and the radial direction of the furnace body 110 is 5-22 degrees, and can also be selected from 8-20 degrees, 5-15 degrees or 5-10 degrees. The inclination angle of the second gasifying agent nozzle 120 is in a proper range, which is beneficial to forming a good temperature field and a good flow field in the gasification chamber, and is further beneficial to reducing CH of coal gas₄The content of the coal gas is high, and the coal gas obtains a high effective gas ratio.

Preferably, the second gasifying agent nozzle 120 extends into the gasification chamber to a depth of 300mm to 350 mm. The depth of the second gasifying agent nozzle 120 extending into the gasification chamber represents the depth of the second gasifying agent nozzle 120The vertical distance from the outlet to the inner side wall of the furnace body 110. The length of the second gasifying agent nozzle 120 extending into the gasification chamber is in a proper range, which is beneficial to forming a good temperature field and a good flow field in the gasification chamber, and further beneficial to reducing CH of coal gas₄The content of the coal gas is high, and the coal gas obtains a high effective gas ratio.

In some embodiments, the first gasifying agent introducing port 111 is disposed at a height denoted by g, wherein: g is more than or equal to 0.1H and less than or equal to 0.3H. In some embodiments, 0.15H ≦ g ≦ 0.25H. In some embodiments, 0.1H ≦ g ≦ 0.2H. In some embodiments, 0.12H ≦ g ≦ 0.17H. In some embodiments, 0.13H ≦ g ≦ 0.18H. The setting height g of the first gasifying agent introducing port 111 means a vertical distance from a horizontal line at the center of the first gasifying agent introducing port 111 to the bottom surface 110c of the bottom flange.

In some embodiments, a plurality of first gasifying agent introduction ports 111 may be provided at a lower region of the furnace body 110 at intervals in the circumferential direction of the furnace body 110. For example, the first gasifying agent introduction port 111 is 4, 5 or 6. The plurality of first gasifying agent introduction ports 111 are preferably uniformly distributed in the circumferential direction of the furnace body 110.

A first gasifying agent nozzle 130 may be provided at the first gasifying agent introducing port 111. A first gasification agent is provided to the gasification chamber through a first gasification agent nozzle 130. Preferably, the first gasifying agent nozzle 130 is obliquely arranged from the coal inlet to the slag outlet, wherein an included angle between the first gasifying agent nozzle 130 and the radial direction of the furnace body 110 is 10-30 degrees, more preferably 15-25 degrees, such as 19 degrees.

Preferably, the first gasifying agent nozzle 130 extends into the gasification chamber to a depth of 300mm to 350 mm. The depth to which the first oxidant nozzle 130 extends into the gasification chamber represents the vertical distance from the outlet of the first oxidant nozzle 130 to the inside wall of the furnace body 110.

The gas outlet 113 of the coal gasification furnace 100 may be disposed at a position near the coal inlet of the furnace body 110 to make full use of sensible heat of the gas. In some embodiments, the height of the gas outlet 130 is denoted as t, wherein: h-t is more than or equal to 0.03H and less than or equal to 0.2H. In some embodiments, 0.05H ≦ H-t ≦ 0.1H. In some embodiments, 0.05H ≦ H-t ≦ 0.15H. The height h of the gas outlet 130 is defined as the vertical distance from the horizontal line of the center of the gas outlet 130 to the bottom surface of the bottom flange 110 c.

The coal gasification process according to the invention can be carried out with a coal gasifier according to the invention, producing coal with low CH₄And coal gas with tar content and high effective gas content.

The invention also provides a coal gasification system. The system can implement the coal gasification process of the invention to produce coal with low CH₄And coal gas with tar content and high effective gas content. Fig. 2 is a flow chart of a coal gasification system as an example. Referring to fig. 2, a coal gasification system according to the present invention includes a coal gasification furnace 100 and a gasification agent supply assembly 200.

The coal gasification furnace 100 employs the coal gasification furnace 100 according to the present invention.

The gasifying agent supply unit 200 is configured to supply a first gasifying agent to the gasification chamber of the coal gasifier 100 through the first gasifying agent introduction port 111 so that the first gasifying agent performs a combustion reaction with the coal material subjected to the gasification treatment in the upper and middle regions of the furnace body 110, and supply a second gasifying agent to the gasification chamber of the coal gasifier 100 through the second gasifying agent introduction port so that the second gasifying agent participates in the gasification reaction to generate coal gas. The gasifying agent supply unit 200 may employ a unit for supplying gasifying agent to the coal gasifier 100, which is known in the art. For example, the gasifying agent supply assembly 200 may include a steam pipe, an oxygen pipe, a steam-oxygen mixer 210 connected to the steam pipe and the oxygen pipe, and a steam-oxygen pipe connected between the steam-oxygen mixer 210 and the coal gasifier 100.

In some embodiments, the coal gasification system further comprises a dust removal device 300. The inlet of the dust removing device 300 is connected to the gas outlet 113 of the coal gasifier 100, and is used for removing dust from the coal gas sent from the coal gasifier 100. The dust removing device 300 may employ a device for gas dust removal known in the art, such as a venturi scrubber. The venturi scrubber may employ a scrubbing liquid known in the art, such as water.

The coal gas delivered from the coal gasification furnace 100 has a high temperature, and in some embodiments, the coal gasification system may further include a waste heat recovery device 400 for waste heat recovery. The waste heat recovery device 400 may be connected to a gas outlet of the dust removing device 300, and is used for recovering waste heat from the gas from the dust removing device 300. The waste heat recovery device 400 may employ a device known in the art that can be used for gas waste heat recovery, such as a waste heat boiler.

In some embodiments, the coal gasification system comprises a dust removal device 300 and a waste heat recovery device 400, the dust removal device 300 comprising a venturi scrubber. The coal gasification system further includes a gas-liquid separation device 500 and a waste liquid treatment device 600. The gas-liquid separation device 500 is connected to a gas outlet of the waste heat recovery device 400, and is configured to perform gas-liquid separation on the gas from the waste heat recovery device 400. The inlet of the waste liquid treatment device 600 is respectively connected with the liquid outlets of the waste heat recovery device 400 and the gas-liquid separation device 500, and the liquid outlet of the waste liquid treatment device 600 is connected with the washing liquid inlet of the venturi scrubber. The waste liquid treatment device 600 is used for purifying waste liquid from the waste heat recovery device 400 and the gas-liquid separation device 500, and sending the purified liquid to the venturi scrubber for recycling. The gas-liquid separation device 500 and the waste liquid treatment device 600 may each employ a device known in the art. For example, the gas-liquid separation device 500 may be selected from gas-liquid separators using a separation structure such as gravity settling, baffling separation, centrifugal separation, wire mesh separation, ultrafiltration separation, or packing separation. The waste liquid treatment apparatus 600 may employ, for example, a solid-liquid separation device such as a settling tank.

Although not shown in the drawings, the coal gasification system of the present invention may further optionally include a coal feeding unit, a slag discharging unit, a jacket water circulating unit (the furnace body may be provided with a cooling water jacket), and the like. The coal charging unit, the slag discharging unit, and the jacket water circulating unit may each include related devices known in the art. As an example, the coal charging unit may include a coal lock connected to the coal inlet. As an example, the slag tapping unit may include a quench chamber and a slag lock, etc., connected to the slag tap.

The coal gas produced by the coal gasification method and the system can be used as chemical raw material gas, industrial gas, fuel gas and the like. For example, coal gas may be used as the feed gas for the synthesis of ammonia. Due to CH in the coal gas₄The content is reduced, thereby being advantageousThe purge gas amount and the energy consumption of the ammonia synthesis system are reduced. In some embodiments, the temperature of the coal gas sent out by the coal gasifier can be reduced to 180-190 ℃ after dust removal, waste heat recovery and gas-liquid separation, and the coal gas can be directly sent to the subsequent working section.

The invention next provides a coal gasification ammonia synthesis system. FIG. 3 is a flow diagram of a coal gasification ammonia synthesis system as one example. Referring to fig. 3, a coal gasification ammonia synthesis system according to an embodiment of the present invention includes a gas making unit 1, a shift unit 2, a decarbonization unit 3, a double-methanol refining unit 4, and an ammonia synthesis unit 5.

The gas making unit 1 comprises the coal gasification system of the invention. The gas making unit 1 gasifies the raw material coal to produce coal gas. The coal gas of the coal gasification system can be directly sent into the conversion unit 2 for conversion treatment.

The conversion unit 2 is connected with the gas outlet of the gas making unit 1 and is used for receiving the synthesis gas from the gas making unit 1 and converting the synthesis gas to convert CO into CO₂And sending out the transformation gas. Because the temperature of the coal gas sent out from the coal gas outlet is higher, the content of the water vapor in the coal gas after washing and dust removal is increased (for example, 40-45 percent), and the amount of the water vapor supplemented by the conversion process is greatly reduced, thereby being beneficial to further reducing the energy consumption of the whole ammonia synthesis system.

The decarbonizing unit 3 is configured to decarbonize the shift gas from the shift unit 2 to obtain a decarbonized gas. Decarbonizing CO in a decarbonized gas₂The content is obviously reduced.

The double refining unit 4 is used for double refining the decarbonized gas from the decarbonization unit 3 to obtain a raw material gas. Refining with methanol or methanation to obtain CO and CO in the decarbonized gas₂And a methyl compound is produced as a byproduct. The content of carbon oxide in the raw material gas reaches the strict requirement of synthetic ammonia by the refining treatment of the dimethyl formamide.

The synthesis ammonia unit 5 is used for receiving the raw material gas from the double-methyl refining unit 4 and synthesizing ammonia by using the raw material gas.

Referring to fig. 4, in some embodiments, if the sulfur content of the syngas from the gas-generating unit 1 is greater than 0.05ppm, the system may further include a shift unit 6 and a desulfurization unit 7. The shift unit 6 and the desulfurization unit 7 are sequentially disposed between the shift unit 2 and the decarburization unit 3, and are used for desulfurizing the synthesis gas.

The shift unit 2, the decarbonization unit 3, the dimethyl refining unit 4, the ammonia synthesis unit 5, the shift unit 6 and the desulfurization unit 7 can adopt the processes and devices known in the art.

In this context, the content of the components in the gas is referred to as volume percentage.

Examples

Example 1

The coal gasification furnace is a liquid slag-discharging fixed bed gasification furnace. And 6 first gasifying agent introducing openings are uniformly distributed in the lower area of the furnace body along the circumferential direction of the furnace body. The set height g of the first gasifying agent introducing port is equal to 0.12 times the height H of the furnace body. A first gasifying agent nozzle is provided at the first gasifying agent introducing port. And 4 second gasifying agent introducing openings are uniformly distributed in the middle area of the furnace body along the circumferential direction of the furnace body. The height H of the second gasifying agent introducing port is equal to 0.45 times of the height H of the furnace body. The second gasifying agent introducing port is provided with a second gasifying agent nozzle.

The raw material coal is anthracite block coal, and the ash melting point of the anthracite block coal is 1450 ℃.

The first gasifying agent is a mixed gas of oxygen and superheated water vapor, and the steam-oxygen ratio is 0.96kg/Nm³。

The second gasifying agent is a mixed gas of oxygen and superheated steam, and the steam-oxygen ratio is 3.0kg/Nm³。

The raw material coal is added into the gasification chamber from a coal inlet at the top of the coal gasification furnace through a coal lock, the first gasification agent is added into the gasification chamber through a first gasification agent nozzle, the second gasification agent is added into the gasification chamber through a second gasification agent nozzle, and the volume flow ratio of oxygen introduced into the gasification chamber by the first gasification agent to oxygen introduced into the gasification chamber by the second gasification agent is 6: 4. Under the gasification pressure of 2.5MPa, the raw material coal is gasified to generate coal gas which is sent out from a coal gas outlet. The furnace temperature curve is shown in fig. 5, in which the abscissa indicates the height (based on the bottom surface of the bottom flange), the ordinate indicates the temperature (deg.c) in the furnace, and the vertical dotted line from left to right indicates the installation position of the first gasifying agent introduction port, the installation position of the second gasifying agent introduction port, and the installation position of the gas outlet in this order. The temperature of the gas at the gas outlet was about 900 ℃. The composition of the gas is shown in Table 1.

TABLE 1

Composition (I)	H2	CO	CO2	CH4	Tar oil
						Content (wt.)	37.2％	51.91％	9.2％	1.4％	0.29％

Example 2

Unlike example 1, the first gasifying agent introducing port was set at a height g equal to 0.15 times the furnace height H; the setting height H of the second gasifying agent introducing port is equal to 0.5 time of the height H of the furnace body; the raw material coal is bituminous coal lump coal, and the ash melting point of the bituminous coal lump coal is 1380 ℃; the steam-oxygen ratio of the second gasifying agent is 4.0kg/Nm³(ii) a The gasification pressure was 4.0 MPa. The temperature profile in the furnace is shown in FIG. 6, in which the abscissa represents the height (with bottom flange bottom)The surface is taken as a reference), the ordinate represents the temperature (DEG C) in the furnace, and the vertical dotted line from left to right represents the installation position of the first gasifying agent introduction port, the installation position of the second gasifying agent introduction port, and the installation position of the gas outlet in this order. The temperature of the gas at the gas outlet was about 900 ℃. The composition of the gas is shown in Table 2.

TABLE 2

Composition (I)	H2	CO	CO2	CH4	Tar oil
						Content (wt.)	34.31％	48.39％	14.9％	1.49％	0.91％

From the above results, it is understood that a high-quality coal gas product can be obtained by the coal gasification method and system of the present invention. Tar and CH in coal gas₄The content of (A) is low, and the content of effective gas is high. In addition, the tar content of the coal gas is reduced, so that the problem of wastewater treatment can be effectively relieved.

While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.