Method for quickly extracting coal tar processing products

Abstract

The present invention provides a method for quickly extracting coal tar processed products, and relates to the technical field of refined coal tar production methods. When the process is started, after a hydrorefining unit performs a hydrogenation reaction, unqualified hydrogenated products are recycled and added to the hydrorefining unit. Since, after passing through the hydrorefining unit, although the output is still unqualified products, the unqualified products contain saturated aromatic hydrocarbons, which can reduce unstable reaction factors in the hydrorefining unit, so that the hydrogenation reaction proceeds stably, so that the temperature of the hydrorefining unit stably rises to a first predetermined temperature, and qualified refined coal tar can be quickly extracted.

Description

Technical Field

[0001] The invention belongs to the technical field of refined coal tar production methods, and in particular relates to a method for rapidly extracting coal tar processed products. Background Art

[0002] In the process of producing refined coal tar from coal tar, the coal tar is pre-treated to remove impurities, then refined by hydrogenation, and the refined hydrogenation product is fractionated to obtain refined coal tar; however, during the start-up process, the temperature of the hydrogenation refining reactor cannot reach the predetermined reaction temperature, resulting in a large amount of unqualified hydrogenation products being produced in the early stage, and the start-up time is long. Summary of the Invention

[0003] In view of this, the present invention provides a method for rapidly producing coal tar processed products by rapidly increasing the reactor temperature to produce qualified hydrogenation products and shortening the start-up time.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A method for rapidly recovering coal tar processed products is applied to a coal tar processed product system, wherein the coal tar processed product system comprises a pretreatment unit, a hydrofining unit, and a fractionation unit connected in sequence;

[0006] During operation, after the hydrogenation reaction in the hydrorefining unit, unqualified hydrogenation products are recycled and added to the pretreatment unit, and then added to the hydrorefining unit, so that the temperature of the hydrorefining unit can be stably increased to the first predetermined temperature, so that qualified refined coal tar can be quickly produced.

[0007] Preferably, at the start of operation, the raw coal tar is pretreated in the pretreatment unit and then added to the hydrorefining unit for hydrogenation reaction.

[0008] Preferably, at the start of operation, C10 crude aromatics are added to the hydrorefining unit for hydrogenation reaction.

[0009] Preferably, the qualified hydrogenated product outputted from the hydrotreating unit is transported to a fractionation unit for fractionation.

[0010] Preferably, the temperature of the hydrotreating unit is steadily increased to a first predetermined temperature of 340°C to 390°C.

[0011] Preferably, the hydrotreating unit includes a first reactor, a second reactor, and a third reactor, which are connected in series. When started, the outlet temperature of the first reactor needs to be stabilized at a first constant temperature, and the outlet temperature of the second reactor needs to be stabilized at a second constant temperature, so that the outlet temperature of the third reactor reaches a first predetermined temperature.

[0012] Preferably, the first constant temperature is 300°C-335°C, and the second constant temperature is 330°C-375°C.

[0013] Preferably, the C10 crude aromatics are simultaneously transported to the fractionation unit so that the fractionation unit can be quickly operated to the second predetermined temperature to receive the qualified hydrogenated products produced by the hydrotreating unit.

[0014] Preferably, the fractionation unit is operated to a second predetermined temperature of 300°C-340°C.

[0015] Preferably, after the hydrotreating unit and the fractionation unit are able to produce qualified products, the following steps are performed to carry out normal production:

[0016] The first step: transport the raw coal tar to the pretreatment unit for pretreatment to remove solids and asphalt to obtain the mid-stage material;

[0017] Step 2: transporting the middle section material to the hydrotreating unit for hydrotreating to obtain a hydrogenated product containing saturated aromatics;

[0018] Step 3: The hydrogenation product containing saturated aromatics is transported to the fractionation unit for fractionation to obtain refined coal tar and C10 crude aromatics.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The method for rapidly recovering coal tar processed products provided by the present invention is applied to a coal tar processed product system, wherein the coal tar processed product system comprises a pretreatment unit, a hydrorefining unit, and a fractionation unit which are connected in sequence. When the system is started, after the hydrorefining unit performs a hydrogenation reaction, unqualified hydrogenated products are recycled and added to the hydrorefining unit. Although unqualified products are still produced after passing through the hydrorefining unit, the unqualified products contain saturated aromatic hydrocarbons, which can reduce unstable reaction factors in the hydrorefining unit, allowing the hydrogenation reaction to proceed stably, so that the temperature of the hydrorefining unit can be stably increased to a first predetermined temperature, and qualified refined coal tar can be rapidly recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a block diagram of the coal tar processing product system.

[0022] Figure 2 This is a partial flow chart of the coal tar processing product system.

[0023] In the figure: coal tar processing product system 10, pretreatment unit 100, middle material storage tank 110, hydrorefining unit 200, first reactor 210, heating furnace 211, hydrogen mixing pipeline 212, second reactor 220, third reactor 230, first heat exchanger 231, second heat exchanger 232, third heat exchanger 233, hydrogenation product storage tank 240, hydrogen pipeline 250, fractionation unit 300, stabilization tower 310, fourth heat exchanger 311, fractionation tower 320, fifth heat exchanger 321, side tower 330, sixth heat exchanger 331, refined coal tar storage tank 340, C10 crude aromatics storage tank 350, fractionation tower bottom material storage tank 360. DETAILED DESCRIPTION

[0024] The technical solutions and technical effects of the embodiments of the present invention are further elaborated below in conjunction with the accompanying drawings of the present invention.

[0025] Please see Figures 1 to 2 A method for rapidly recovering coal tar processed products is applied to a coal tar processed product system 10, wherein the coal tar processed product system 10 includes a pretreatment unit 100, a hydrofining unit 200, and a fractionation unit 300 connected in sequence;

[0026] During operation, after the hydrogenation reaction in the hydrorefining unit 200, unqualified hydrogenated products are recycled and added to the pretreatment unit 100, and then added to the hydrorefining unit 200, so that the temperature of the hydrorefining unit 200 can be stably increased to the first predetermined temperature, so that qualified refined coal tar can be quickly produced.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The method for rapidly recovering coal tar processed products provided by the present invention is applied to a coal tar processed product system 10, wherein the coal tar processed product system 10 comprises a pretreatment unit 100, a hydrofining unit 200, and a fractionation unit 300 connected in sequence; on the one hand, when the process is started, after the hydrofining unit 200 performs a hydrogenation reaction, unqualified hydrogenated products are recycled and added to the hydrofining unit 200. After passing through the hydrofining unit 200, although the output is still unqualified products, the unqualified products contain saturated and aromatics, which can reduce unstable reaction factors in the hydrotreating refining unit 200, allowing the hydrogenation reaction to proceed stably, so that the temperature of the hydrotreating refining unit 200 can be stably increased to the first predetermined temperature, and qualified hydrogenation products can be quickly extracted and then transported to the fractionation unit 300 for fractionation, so that refined coal tar can be quickly extracted; on the other hand, when the operation is started, after the hydrotreating refining unit 200 carries out the hydrogenation reaction, the unqualified hydrogenation products produced will not be directly transported to the fractionation unit 300, and will not cause pollution to the fractionation unit 300.

[0029] Furthermore, at the start of operation, the raw coal tar is pretreated in the pretreatment unit 100 and then added to the hydrorefining unit 200 for hydrogenation reaction.

[0030] Furthermore, at the start-up, C10 crude aromatics are added to the hydrorefining unit 200 for hydrogenation reaction.

[0031] Furthermore, the qualified hydrogenated product produced by the hydrotreating unit 200 is transported to the fractionation unit 300 for fractionation.

[0032] Furthermore, the temperature of the hydrotreating unit 200 is stably increased to a first predetermined temperature of 340°C to 390°C.

[0033] Furthermore, the hydrotreating unit 200 includes a first reactor 210, a second reactor 220, and a third reactor 230. The first reactor 210, the second reactor 220, and the third reactor 230 are connected in series in sequence. When starting up, the outlet temperature of the first reactor 210 needs to be stabilized at a first constant temperature, and the outlet temperature of the second reactor 220 needs to be stabilized at a second constant temperature so that the outlet temperature of the third reactor 230 reaches a first predetermined temperature.

[0034] Furthermore, the first constant temperature is 300°C-335°C, and the second constant temperature is 330°C-375°C.

[0035] Specifically, the hydrotreating unit 200 further includes a hydrogenation product storage tank 240, the hydrotreating unit 200 further includes a heating furnace 211, a first heat exchanger 231, a second heat exchanger 232, a third heat exchanger 233, a hydrogen pipeline 250, and a hydrogen mixing pipeline 212. The pretreatment unit 100 includes a middle section material storage tank 110, the outlet of the middle section material storage tank 110 is connected to the shell side inlet of the first heat exchanger 231, the shell side outlet of the first heat exchanger 231 is connected to the inlet of the first reactor 210, the hydrogen mixing pipeline 212 is connected to the shell side inlet of the second heat exchanger 232, the shell side outlet of the second heat exchanger 232 is connected to the inlet of the heating furnace 211, and the heating furnace 211 is connected to the second The material coming out of the shell side outlet of the heat exchanger 232 is heated, the fractionation unit 300 is connected to the shell side inlet of the third heat exchanger 233, the shell side outlet of the third heat exchanger 233 is connected to the fractionation unit 300, the outlet of the first reactor 210 is connected to the inlet of the second reactor 220, the outlet of the second reactor 220 is connected to the inlet of the third reactor 230, the outlet of the third reactor 230 is connected to the tube side inlet of the third heat exchanger 233, the tube side outlet of the third heat exchanger 233 is connected to the tube side inlet of the second heat exchanger 232, the tube side outlet of the second heat exchanger 232 is connected to the tube side inlet of the first heat exchanger 231, and the tube side outlet of the first heat exchanger 231 is connected to the tube side outlet of the first heat exchanger 231. The outlet of the process is connected to the inlet of the hydrogenation product storage tank 240, the outlet of the hydrogenation product storage tank 240 is connected to the inlet of the fractionation unit 300, and the outlet of the hydrogen pipeline 250 is connected to the inlets of the first reactor 210, the second reactor 220, and the third reactor 230 respectively for hydrogenation reaction; on the one hand, when the hydrogenation product is cooled by the first heat exchanger 231, the second heat exchanger 232, and the third heat exchanger 233, since the inlet temperature of the first reactor 210 needs to reach 250°C-280°C, the middle section material is heat exchanged by the hydrogenation product, which not only cools the hydrogenation product but also heats the middle section material, reduces energy waste, improves the utilization of waste heat, and is more environmentally friendly; on the other hand, The segment materials and the hydrogenation materials exchange heat with each other. If the tube bundle leaks in the first heat exchanger 231, the second heat exchanger 232, and the third heat exchanger 233, there is no need to worry about the product being contaminated and affecting the subsequent industrial chain because the material composition is the same. The materials in the hydrogenation product storage tank 240 and the fractionation unit 300 can be transported to the middle segment material storage tank 110 for reuse and re-separation to avoid pollution. On the other hand, after the first reactor 210 carries out the hydrogenation reaction, the hydrogenation reaction begins to release heat, so that the inlet temperature of the second reactor 220 gradually increases. After the second reactor 220 carries out the hydrogenation reaction, the reaction releases heat, so that the inlet temperature of the third reactor 230 gradually increases, so that the temperature of the entire hydrotreating refining unit 200 rises steadily to start normal and stable operation.

[0036] Furthermore, the C10 crude aromatics are simultaneously transported to the fractionation unit 300 so that the fractionation unit 300 can quickly operate to a second predetermined temperature to receive qualified hydrogenated products produced by the hydrotreating unit 200, so that the fractionation unit 300 can operate to a normal operating state. The qualified hydrogenated products produced by the hydrotreating unit 200 can be separated normally, saving start-up time. After the hydrotreating unit 200 produces qualified hydrogenated products, the qualified hydrogenated products produced by the hydrotreating unit 200 will not be used to replace the unqualified products of the fractionation unit 300, thereby improving the product output time.

[0037] Furthermore, the fractionation unit 300 is operated to a second predetermined temperature of 300°C-340°C, and the inlet temperature of the fractionation tower 320 is 300°C-340°C.

[0038] Furthermore, the fractionation unit 300 includes a stabilizing tower 310, a fractionating tower 320, a side tower 330, a refined coal tar storage tank 340, a C10 crude aromatics storage tank 350, and a fractionating tower bottom material storage tank 360. The stabilizing tower 310 is provided with a fourth heat exchanger 311, the fractionating tower 320 is provided with a fifth heat exchanger 321, and the side tower 330 is provided with a sixth heat exchanger 331. The outlet of the hydrogenation product storage tank 240 is connected to the pipe side inlet of the fourth heat exchanger 311. The outlet of the fourth heat exchanger 311 is connected to the pipe side inlet of the fourth heat exchanger 311. The tube-side outlet is connected to the inlet of the stabilization tower 310, the bottom outlet of the stabilization tower 310 is connected to the shell-side inlet of the fourth heat exchanger 311, the shell-side outlet of the fourth heat exchanger 311 is connected to the shell-side inlet of the third heat exchanger 233, the shell-side outlet of the third heat exchanger 233 is connected to the inlet of the fractionation tower 320, the top outlet of the fractionation tower 320 is connected to the refined coal tar storage tank 340, and the side outlet of the fractionation tower 320 is connected to the inlet of the side tower 330. The bottom outlet of the side tower 330 is connected to the inlet of the C10 crude aromatics storage tank 350, the outlet of the C10 crude aromatics storage tank 350 is connected to the tube-side inlet of the fourth heat exchanger 311, the top outlet of the side tower 330 is connected to the side inlet of the fractionating tower 320, the bottom outlet of the fractionating tower 320 is connected to the tube-side inlet of the fifth heat exchanger 321, the tube-side outlet of the fifth heat exchanger 321 is connected to the inlet of the fractionating tower 320, and the bottom outlet of the stabilizing tower 310 is connected to the inlet of the fractionating tower 320. The outlet is connected to the shell-side inlet of the fifth heat exchanger 321, the shell-side outlet of the fifth heat exchanger 321 is connected to the inlet of the stabilization tower 310, the tube-side outlet of the fifth heat exchanger 321 is also connected to the shell-side inlet of the sixth heat exchanger 331, and the shell-side outlet of the sixth heat exchanger 331 is connected to the distillation tower bottom material storage tank 360; self-heat exchange is carried out through the above-mentioned fourth heat exchanger 311, the fifth heat exchanger 321, and the sixth heat exchanger 331, with high heat utilization rate and no need to worry about pollution.

[0039] Furthermore, after the hydrotreating unit 200 and the fractionation unit 300 are able to produce qualified products, the following steps are performed to carry out normal production:

[0040] Step 1: The raw coal tar is transported to the pretreatment unit 100 for pretreatment to remove solids and asphalt to obtain the mid-stage material;

[0041] Step 2: transporting the middle section material to the hydrotreating unit 200 for hydrotreating to obtain a hydrogenated product containing saturated aromatics;

[0042] Step 3: The hydrogenation product containing saturated aromatics is transported to the fractionation unit 300 for fractionation to obtain refined coal tar and C10 crude aromatics. Example 1:

[0043] The outlet of the middle material storage tank 110 is connected to the shell-side inlet of the first heat exchanger 231, the shell-side outlet of the first heat exchanger 231 is connected to the inlet of the first reactor 210, the hydrogen mixing pipeline 212 is connected to the shell-side inlet of the second heat exchanger 232, the shell-side outlet of the second heat exchanger 232 is connected to the inlet of the heating furnace 211, and the heating furnace 211 heats the material coming out of the shell-side outlet of the second heat exchanger 232. The fractionation unit 300 is connected to the shell-side inlet of the third heat exchanger 233. The first reactor 21 The outlet of the hydrogen pipeline 250 is connected to the inlet of the second reactor 220, the outlet of the second reactor 220 is connected to the inlet of the third reactor 230, the outlet of the hydrogen pipeline 250 is connected to the inlet of the first reactor 210, the second reactor 220, and the third reactor 230 respectively for hydrogenation reaction, the outlet of the third reactor 230 is connected to the tube-side inlet of the third heat exchanger 233, the tube-side outlet of the third heat exchanger 233 is connected to the tube-side inlet of the second heat exchanger 232, and the tube-side outlet of the second heat exchanger 232 is connected to the tube-side outlet of the third heat exchanger 233. The tube-side inlet of the first heat exchanger 231 is connected, the tube-side outlet of the first heat exchanger 231 is connected to the inlet of the hydrogenated product storage tank 240, the outlet of the hydrogenated product storage tank 240 is also connected to the inlet of the middle material storage tank 110, the outlet of the hydrogenated product storage tank 240 is connected to the tube-side inlet of the fourth heat exchanger 311, the tube-side outlet of the fourth heat exchanger 311 is connected to the inlet of the stabilization tower 310, the bottom outlet of the stabilization tower 310 is connected to the shell-side inlet of the fourth heat exchanger 311, and the shell-side outlet of the fourth heat exchanger 311 is connected to the third heat exchanger. The shell side inlet of the heat exchanger 233 is connected, the shell side outlet of the third heat exchanger 233 is connected to the inlet of the fractionating tower 320, the top outlet of the fractionating tower 320 is connected to the refined coal tar storage tank 340, the side outlet of the fractionating tower 320 is connected to the inlet of the side tower 330, the bottom outlet of the side tower 330 is connected to the inlet of the C10 crude aromatics storage tank 350, the top outlet of the side tower 330 is connected to the side inlet of the fractionating tower 320, and the outlet of the C10 crude aromatics storage tank 350 is connected to the tube side inlet of the fourth heat exchanger 311;At the start of operation, the raw coal tar is pretreated in the pretreatment unit 100 and then added to the hydrofining unit 200 for hydrogenation reaction, or the C10 crude aromatics are added to the hydrofining unit 200 for hydrogenation reaction. The unqualified hydrogenated products are stored in the hydrogenated product storage tank 240, recycled from the hydrogenated product storage tank 240 to the middle material storage tank 110, and then added to the hydrofining unit 200 for hydrogenation again, so that the temperature of the hydrofining unit 200 rises steadily and the first reactor 210 The outlet temperature of the reactor 220 is stabilized at 325°C, and the outlet temperature of the second reactor 220 is stabilized at 355°C, so that the outlet temperature of the third reactor 230 reaches 370°C. At the same time, the C10 crude aromatics in the C10 crude aromatics storage tank 350 are transported to the stabilization tower 310 and the fractionation tower 320, so that the fractionation tower 320 also operates normally at 320°C and can directly receive the qualified hydrogenated product output by the hydrorefining unit 200 for normal production of refined coal tar. The operating time used is 6-8 hours.

[0044] Comparative Example 1:

[0045] The outlet of the middle material storage tank 110 is connected to the shell-side inlet of the first heat exchanger 231, the shell-side outlet of the first heat exchanger 231 is connected to the inlet of the first reactor 210, the hydrogen mixing pipeline 212 is connected to the shell-side inlet of the second heat exchanger 232, the shell-side outlet of the second heat exchanger 232 is connected to the inlet of the heating furnace 211, and the heating furnace 211 heats the material coming out of the shell-side outlet of the second heat exchanger 232. The fractionation unit 300 is connected to the shell-side inlet of the third heat exchanger 233, and the outlet of the first reactor 210 is connected to the second reactor 210. The inlet of the reactor 220 is connected, the outlet of the second reactor 220 is connected to the inlet of the third reactor 230, the outlet of the hydrogen pipeline 250 is connected to the inlets of the first reactor 210, the second reactor 220 and the third reactor 230 respectively for hydrogenation reaction, the outlet of the third reactor 230 is connected to the tube-side inlet of the third heat exchanger 233, the tube-side outlet of the third heat exchanger 233 is connected to the tube-side inlet of the second heat exchanger 232, the tube-side outlet of the second heat exchanger 232 is connected to the tube-side inlet of the first heat exchanger 231, and the first heat exchanger The tube-side outlet of 231 is connected to the inlet of the hydrogenated product storage tank 240, the outlet of the hydrogenated product storage tank 240 is connected to the tube-side inlet of the fourth heat exchanger 311, the tube-side outlet of the fourth heat exchanger 311 is connected to the inlet of the stabilization tower 310, the bottom outlet of the stabilization tower 310 is connected to the shell-side inlet of the fourth heat exchanger 311, the shell-side outlet of the fourth heat exchanger 311 is connected to the shell-side inlet of the third heat exchanger 233, the shell-side outlet of the third heat exchanger 233 is connected to the inlet of the fractionation tower 320, and the top outlet of the fractionation tower 320 is connected to the refined coal coke. The oil storage tank 340 is connected, the side outlet of the fractionating tower 320 is connected to the inlet of the side tower 330, the bottom outlet of the side tower 330 is connected to the inlet of the C10 crude aromatics storage tank 350, and the top outlet of the side tower 330 is connected to the side inlet of the fractionating tower 320; when the operation is started, the raw coal tar is pretreated by the pretreatment unit 100 and then added to the hydrorefining unit 200 for hydrogenation reaction, and then the hydrogenation product is transported to the fractionating unit 300 for fractionation. When the fractionating tower 320 operates normally to 320°C and produces refined coal tar normally, the start-up time used is 28h-32h.

[0046] It can be seen from the above embodiments and comparative examples that the scheme of the present invention can greatly shorten the start-up time and can quickly produce refined coal tar.

[0047] The above disclosure is only a preferred embodiment of the present invention, and it is certainly not intended to limit the scope of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for rapidly recovering coal tar processed products, characterized by: Applicable to a coal tar processing product system, the coal tar processing product system includes a pretreatment unit, a hydrofining unit, and a fractionation unit connected in sequence; At the start-up, after the hydrogenation reaction in the hydrorefining unit, unqualified hydrogenated products are recycled and added to the pretreatment unit, and then added to the hydrorefining unit, so that the temperature of the hydrorefining unit is stably increased to the first predetermined temperature, so that qualified refined coal tar can be quickly produced; The hydrotreating unit includes a first reactor, a second reactor, and a third reactor, which are sequentially connected in series. When the unit is started, the outlet temperature of the first reactor needs to be stabilized at a first constant temperature, and the outlet temperature of the second reactor needs to be stabilized at a second constant temperature, so that the outlet temperature of the third reactor reaches a first predetermined temperature. The first predetermined temperature is 340°C-390°C, the first constant temperature is 300°C-335°C, and the second constant temperature is 330°C-375°C.

2. The method for rapidly recovering coal tar processed products according to claim 1, wherein: At the start of operation, the raw coal tar is pretreated in the pretreatment unit and then added to the hydrorefining unit for hydrogenation reaction.

3. The method for rapidly recovering coal tar processed products according to claim 1, wherein: At the start-up, C10 crude aromatics are added to the hydrorefining unit for hydrogenation reaction.

4. The method for rapidly recovering coal tar processed products according to claim 1, wherein: The qualified hydrogenated product outputted from the hydrotreating unit is transported to the fractionation unit for fractionation.

5. The method for rapidly recovering coal tar processed products according to any one of claims 1 to 3, characterized in that: Simultaneously delivering the C10 crude aromatics to the fractionation unit enables the fractionation unit to quickly operate to a second predetermined temperature to receive qualified hydrogenated products produced by the hydrotreating unit.

6. The method for rapidly recovering coal tar processed products according to claim 5, wherein: The fractionation unit is operated to a second predetermined temperature of 300°C-340°C.

7. The method for rapidly recovering coal tar processed products according to claim 6, wherein: After the hydrotreating unit and fractionation unit can produce qualified products, the following steps are carried out to resume normal production: The first step: transport the raw coal tar to the pretreatment unit for pretreatment to remove solids and asphalt to obtain the mid-stage material; Step 2: transporting the middle section material to the hydrotreating unit for hydrotreating to obtain a hydrogenated product containing saturated aromatics; Step 3: The hydrogenation product containing saturated aromatics is transported to the fractionation unit for fractionation to obtain refined coal tar and C10 crude aromatics.

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