Energy-saving device and method for heating modified pitch in a tubular furnace

Abstract

The present application belongs to the technical field of metallurgical coking, and particularly relates to an energy-saving device for heating modified pitch in a tubular furnace and a method thereof, comprising a reaction kettle, a modified pitch circulating pump and a tubular furnace, characterized in that a heat preservation jacket is arranged on the lateral wall and the bottom outside of the reaction kettle, the heat preservation jacket is multi-sectioned and connected in series through pipelines, an expansion joint is arranged between the adjacent heat preservation jackets, the expansion joint is filled with elastic heat preservation material, a gap is arranged between the inner side of the heat preservation jacket and the lateral wall outside of the reaction kettle, the upper and lower ends of the gap are sealed by heat preservation material to form a closed cavity, the smoke inlet of the heat preservation jacket is connected with the flue gas outlet of the tubular furnace, and the flue gas outlet of the heat preservation jacket is connected with an air preheater. Compared with the prior art, the present application has the beneficial effects that the high-temperature flue gas discharged from the tubular furnace is used as a heat preservation medium to isolate the influence of the ambient temperature on the heat dissipation of the reaction kettle, the heat load of the tubular furnace is effectively utilized, and the energy-saving goal is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metallurgical coking, and particularly relates to an energy-saving device for heating modified pitch in a tubular furnace and a method thereof. BACKGROUND

[0002] About 50% to 60% of pitch is generally produced in a coal tar processing process, which is a bulk product of tar processing, and the larger the processing scale is, the more the pitch production is. Modified pitch is a main downstream product of pitch at present, and is mainly used for producing prebaked anodes, battery rods or electrode binders in the electrolytic aluminum industry.

[0003] At present, most of the production processes for producing modified pitch at home adopt a thermal polycondensation method. The thermal polycondensation method can be divided into a kettle heating method and a tubular furnace heating method according to a heating mode. Only the tubular furnace heating method is discussed below.

[0004] The modified pitch production process of the tubular furnace heating method achieves the purpose of pitch modification according to the reaction time and the reaction temperature of the reaction substance of the medium-temperature pitch in the modified pitch reaction kettle. The reaction time is provided by controlling the size of the reaction kettle volume, and the reaction temperature is provided by the tubular heating furnace. There are double-furnace double-kettle processes and single-furnace single-kettle processes. The double-furnace double-kettle process uses medium-temperature pitch as raw material, and the reaction is carried out in two steps. The medium-temperature pitch sent from the tar distillation unit has a temperature of about 370 DEG C, is sent to the 1# reaction kettle, and is subjected to primary modification. The temperature in the reaction kettle is controlled at about 380 DEG C by the 1# tubular furnace, the pitch mainly undergoes a beta-modification reaction, and the flash oil gas produced by flash cracking is discharged from the top of the reaction kettle to the subsequent condenser cooler. The pitch after the primary modification is sent to the 2# reaction kettle, and is subjected to secondary modification. The secondary modification reaction process of the pitch is basically the same as the primary modification reaction process. The temperature in the reaction kettle is controlled at about 400 DEG C by the 2# tubular furnace, the pitch simultaneously undergoes alpha- and beta-modification reactions, the flash oil gas produced by flash cracking is discharged from the top of the reaction kettle to the subsequent condenser cooler, and the pitch after the secondary modification is the modified pitch product. The single-furnace single-kettle process also uses medium-temperature pitch as raw material, heats the pitch in the tubular heating furnace, and then carries out the reaction in the reaction kettle. The reaction is completed in one step, and the product quality control is not as flexible as that of the double-furnace double-kettle process.

[0005] The production process of modified pitch by the tubular furnace heating method is that the tubular furnace is used as a heat source, and the heat supply of the tubular furnace includes two parts, the heat for heating the raw material to the reaction temperature and the heat for maintaining the reaction temperature. Taking the first modification reaction as an example, the medium temperature pitch raw material at about 370 DEG C is sent to the 1# reaction kettle, and the heat is supplied by the 1# tubular furnace. The medium temperature pitch raw material is heated from 370 DEG C to 380 DEG C for the first modification, and the 380 DEG C reaction temperature of the 1# reaction kettle is maintained. The 380 DEG C reaction temperature of the 1# reaction kettle is maintained, that is, the heat loss of the 1# reaction kettle is compensated. Since the modification reaction needs a residence time of 8-10 hours, the volume of the reaction kettle is huge. Although there is external insulation, the heat loss of the reaction kettle is still huge. Through production practice, only one third of the heat supplied by the tubular furnace is used for the modification reaction, and the other two thirds of the heat supplied by the tubular furnace is used to compensate for the heat loss of the reaction kettle. Therefore, reducing the heat loss of the reaction kettle is the main direction of energy saving. SUMMARY

[0006] The purpose of the present application is to provide a tubular furnace heating modified pitch energy saving device and method, which overcomes the shortcomings of the prior art. The outer shell of the reaction kettle is provided with a heat preservation jacket, the high temperature flue gas discharged by the tubular furnace is introduced into the heat preservation jacket of the reaction kettle, the influence of the ambient temperature on the heat loss of the reaction kettle is isolated, the heat loss of the reaction kettle is reduced, and the heat load of the tubular furnace is reduced, thereby achieving the goal of energy saving.

[0007] In order to achieve the above purpose, the present application realizes the following technical scheme:

[0008] One of the technical schemes: a tubular furnace heating modified pitch energy saving device, comprising a reaction kettle, a modified pitch circulating pump and a tubular furnace, characterized in that a heat preservation jacket is arranged on the outer side of the side wall and the bottom of the reaction kettle, the heat preservation jacket is multi-sectioned and connected in series through a pipeline, an expansion joint is arranged between the adjacent heat preservation jackets, an elastic heat preservation material is filled in the expansion joint, a gap is arranged between the inner side of the heat preservation jacket and the outer side of the side wall of the reaction kettle, the upper and lower ends of the gap are sealed by a heat preservation material to form a closed cavity, the bottom smoke inlet of the lowermost heat preservation jacket is connected with the flue gas outlet of the tubular furnace, the flue gas outlet of the uppermost heat preservation jacket is connected with the heat exchange medium inlet of the air preheater, the heat exchange medium outlet of the air preheater is connected with the subsequent desulfurization and denitrification section, the air inlet of the air preheater is connected with the air blower, and the air outlet of the air preheater is connected with the air inlet of the tubular furnace.

[0009] A temperature recording control instrument is arranged on the pipeline of the flue gas outlet of the uppermost heat preservation jacket, the flue gas outlet of the uppermost heat preservation jacket and the bottom smoke inlet of the lowermost heat preservation jacket are connected through a bypass flue gas pipe, a differential pressure regulating valve is arranged on the bypass flue gas pipe, and the differential pressure regulating valve is interlocked with the temperature recording control instrument.

[0010] The width of the expansion joint is 50-100 mm.

[0011] The width of the gap is 30-80mm.

[0012] The reactor is single reactor or double reactor arrangement.

[0013] The top of the reactor is provided with an independent insulation structure.

[0014] The insulation jacket is provided with 3-10 segments, and the height of each segment is 800-2500mm.

[0015] Technical solution two: an energy-saving method for heating modified pitch in a tubular furnace, characterized in that high-temperature flue gas discharged from the tubular furnace is introduced into the insulation jacket of the reactor, so as to insulate the influence of ambient temperature on heat dissipation of the reactor, reduce heat dissipation of the reactor, and reduce the heat load of the tubular furnace, and the specific control process is as follows:

[0016] 1) making the insulation jacket, the insulation jacket is made on the outside of the side wall and the bottom of the reactor, the insulation jacket is made in segments, expansion joints are left between each segment, and the expansion joints are filled with soft and elastic insulation materials; a gap is left between the insulation jacket and the outer wall of the reactor, and the upper and lower ends of the gap are sealed with insulation materials to form a closed cavity;

[0017] 2) top insulation of the reactor, the top of the reactor is independently insulated to meet the insulation requirements of the top of the reactor;

[0018] 3) flue gas pipeline lapping, the flue gas pipelines are connected in series between the insulation jackets, the flue gas inlet of the lowermost insulation jacket is connected in communication with the flue gas outlet of the tubular furnace, the flue gas outlet of the uppermost insulation jacket is connected to the desulfurization and denitrification section through an air preheater, and a bypass flue gas pipeline is arranged between the flue gas inlet of the lowermost insulation jacket and the flue gas outlet of the uppermost insulation jacket; during the modification of pitch, the flue gas temperature at the outlet of the insulation jacket is controlled to be 350-400 DEG C.

[0019] The power for the flue gas flow in the insulation jacket comes from the induced draft fan of the desulfurization and denitrification device, and the pressure in the insulation jacket is -1 to -2 kPa.

[0020] The flue gas temperature at the outlet of the insulation jacket is controlled by a differential pressure regulating valve on the bypass flue gas pipeline; when the temperature is higher than 400 DEG C, the differential pressure between the inlet and the outlet of the differential pressure regulating valve is reduced, the differential pressure regulating valve is opened, the bypass flue gas flow is increased, and the flue gas flow in the insulation jacket is reduced; when the temperature is lower than 350 DEG C, the differential pressure between the inlet and the outlet of the differential pressure regulating valve is increased, the opening of the differential pressure regulating valve is reduced, the bypass flue gas flow is reduced, and the flue gas flow in the insulation jacket is increased.

[0021] Compared with the prior art, the beneficial effects of the present application are:

[0022] 1) by the reaction kettle shell with thermal insulation jacket, using the high temperature flue gas discharged by the tube furnace as the heat preservation medium, to isolate the influence of ambient temperature on the heat dissipation of the reaction kettle, effectively utilize the waste heat of the flue gas discharged by the tube furnace, can effectively reduce the heat dissipation of the reaction kettle, reduce nearly one third of the heat load of the tube furnace, reduce the consumption of electric energy or steam, so as to realize the goal of energy saving;

[0023] 2) At the same time, it also improves the thermal efficiency of the tube furnace, and has a good effect on energy saving in the production process. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the process flow diagram of the embodiment of the present application.

[0025] In the figure: 1-reaction kettle, 2-modified asphalt circulating pump, 3-tube furnace, 4-thermal insulation jacket, 5-air blower, 6-air preheater, 7-differential pressure regulating valve, 8-expansion joint, 9-void, 10-bypass flue gas pipe, TRC-temperature recording control instrument, PDRC-differential pressure recording control instrument. DETAILED DESCRIPTION

[0026] The technical solutions of the present application will be described in detail below in combination with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all.

[0027] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the specific embodiments needed in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the specific embodiments described below are some embodiments of the present application. For those skilled in the art, other specific embodiments can also be obtained without creative labor on the basis of these specific embodiments.

[0028] The components of the embodiments of the present application described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the specific embodiments is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application.

[0029] See Figure 1is an embodiment process flow schematic diagram of the energy-saving device for heating modified pitch by a tubular furnace according to the present application, comprising a reaction kettle 1, a modified pitch circulating pump 2 and a tubular furnace 3, a heat preservation jacket 4 is arranged on the side wall and the bottom outside of the reaction kettle 1, the heat preservation jacket 4 is multi-section and is connected in series through pipelines, an expansion joint 8 is arranged between adjacent heat preservation jackets 4 in upper and lower directions, the expansion joint 8 is filled with elastic heat preservation materials, a gap 9 is arranged between the inner side of the heat preservation jacket 4 and the outer side of the side wall of the reaction kettle 1, the upper and lower ends of the gap 9 are sealed to form a closed cavity through heat preservation materials; the bottom smoke inlet of the lowermost heat preservation jacket 4 is connected with the flue gas outlet of the tubular furnace 3, the flue gas outlet of the uppermost heat preservation jacket 4 is connected with the heat exchange medium inlet of an air preheater 6, the heat exchange medium outlet of the air preheater 6 is connected with a subsequent desulfurization and denitrification section, the air inlet of the air preheater 6 is connected with an air blower 5, and the air outlet of the air preheater 6 is connected with the combustion air inlet of the tubular furnace 3. The heat preservation jacket 4 is provided with 3-10 sections, and each section has a height of 800-2500 mm.

[0030] A temperature recording control instrument TRC is arranged on the pipeline of the flue gas outlet of the uppermost heat preservation jacket 4, the flue gas outlet of the uppermost heat preservation jacket 4 and the bottom smoke inlet of the lowermost heat preservation jacket 4 are connected through a bypass flue gas pipe 10, a differential pressure regulating valve 7 is arranged on the bypass flue gas pipe 10, the differential pressure regulating valve 7 is interlocked with the temperature recording control instrument TRC, and a pressure differential recording control instrument PDRC is used for detecting and recording the differential pressure value.

[0031] In the embodiment, the width of the expansion joint 8 is 80 mm. The width of the gap 9 is 50 mm. An independent heat preservation structure is arranged on the top of the reaction kettle 1. The height of the reaction kettle 1 is 10 meters, and the heat preservation jacket 4 is provided with 4 sections, and each section has a height of 2300 mm.

[0032] The energy-saving method for heating modified pitch by a tubular furnace according to the present application is that high-temperature flue gas discharged from the tubular furnace is introduced into the heat preservation jacket of the reaction kettle, the influence of ambient temperature on heat dissipation of the reaction kettle is isolated, the heat dissipation of the reaction kettle is reduced, the heat load of the tubular furnace is reduced, and the specific control process is as follows by taking the single-kettle arrangement of the reaction kettle 1 as an example.

[0033] 1) The heat preservation jacket is made, the heat preservation jacket 4 is arranged on the side wall and the bottom outside of the reaction kettle 1, the heat preservation jacket is made in sections, the expansion joint 8 is left between each section, the expansion joint is filled with soft and elastic heat preservation materials; the flue gas temperature discharged from the tubular furnace 3 is 800-1000 DEG C, which is much higher than the reaction temperature 380-400 DEG C of the reaction kettle 1, in order to avoid direct contact, the gap 9 is left between the heat preservation jacket 4 and the outer wall of the reaction kettle 1, the upper and lower ends of the gap 9 are sealed to form a closed cavity through heat preservation materials, the air in the gap is heated by the heat preservation jacket, and plays a role in heat insulation and heat preservation.

[0034] 2) The top of the reactor is insulated, the top of the reactor 1 is independently insulated to meet the insulation requirements of the top of the reactor; the top of the reactor 1 is a gas phase space, which has less heat dissipation, and contains more measuring instruments and process interfaces, and the insulation is mainly to reduce the heat loss of the liquid phase.

[0035] 3) The flue gas pipeline is overlapped, each section of the insulation jacket is connected in series through the flue gas pipe, the flue gas inlet of the lowermost insulation jacket 4 is connected with the flue gas outlet of the tubular furnace 3, the flue gas outlet of the uppermost insulation jacket 4 is connected with the air preheater 6 to the desulfurization and denitrification section, and the bypass flue gas pipe is arranged between the flue gas inlet of the lowermost insulation jacket 4 and the flue gas outlet of the uppermost insulation jacket 4, and the flue gas temperature at the outlet of the insulation jacket is controlled at 400℃ during the asphalt modification process.

[0036] The flue gas flowing out of the insulation jacket 4 is sent to the desulfurization and denitrification device after being forcedly ventilated and heat-exchanged with the tubular furnace through the air preheater 6, the power for the flue gas flowing in the insulation jacket 4 comes from the induced draft fan of the desulfurization and denitrification device, and the pressure in the insulation jacket is-1 to-2 kPa.

[0037] The flue gas flow in the insulation jacket 4 is controlled by the pressure difference regulating valve 7 of the insulation jacket bypass according to the flue gas temperature at the outlet of the insulation jacket, when the flue gas temperature at the outlet of the insulation jacket is higher than 400℃, the pressure difference between the inlet and outlet of the pressure difference regulating valve is reduced, the pressure difference regulating valve is opened, the bypass flue gas flow is increased, and the insulation jacket flue gas flow is reduced; when it is lower than 350℃, the pressure difference between the inlet and outlet of the pressure difference regulating valve is increased, the opening of the pressure difference regulating valve is reduced, the bypass flue gas flow is reduced, and the insulation jacket flue gas flow is increased.

[0038] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. An energy-saving device for heating modified asphalt in a tubular furnace, comprising a reaction vessel, a modified asphalt circulation pump, and a tubular furnace, characterized in that, The reactor's sidewalls and bottom outer sides are equipped with insulation jackets. These jackets are multi-segmented and connected in series via pipelines. Expansion joints are provided between adjacent jackets, filled with elastic insulation material. Gaps exist between the inner sides of the insulation jackets and the outer sides of the reactor's sidewalls, with the upper and lower ends of these gaps sealed with insulation material to form closed cavities. The bottom inlet of the lowest insulation jacket is connected to the flue gas outlet of the tubular furnace, and the flue gas outlet of the highest insulation jacket is connected to the heat exchange medium inlet of the air preheater. The heat exchange medium outlet is connected to the subsequent desulfurization and denitrification section; the air inlet of the air preheater is connected to the air fan; and the air outlet of the air preheater is connected to the air inlet of the tubular furnace. A temperature recording and control instrument is installed on the pipeline of the flue gas outlet of the uppermost insulation jacket. The flue gas outlet of the uppermost insulation jacket and the bottom flue gas inlet of the lowermost insulation jacket are connected by a bypass flue gas pipe. A differential pressure regulating valve is installed on the bypass flue gas pipe, and the differential pressure regulating valve is interlocked with the temperature recording and control instrument. The width of the expansion joint is 50-100 mm.

2. The energy-saving device for heating modified asphalt in a tubular furnace according to claim 1, characterized in that, The width of the gap is 30-80mm.

3. The energy-saving device for heating modified asphalt in a tubular furnace according to claim 1, characterized in that, The reactor can be arranged as a single reactor or a double reactor.

4. The energy-saving device for heating modified asphalt in a tubular furnace according to claim 1, characterized in that, The top of the reactor is equipped with an independent heat preservation structure.

5. The energy-saving device for heating modified asphalt in a tubular furnace according to claim 1, characterized in that, The insulation jacket is provided with 3-10 sections, each section being 800-2500mm in height.

6. An energy-saving method for heating modified asphalt in a tubular furnace using the energy-saving device according to any one of claims 1-5, characterized in that, The high-temperature flue gas emitted from the tubular furnace is introduced into the insulation jacket of the reactor to isolate the reactor from the influence of ambient temperature on heat dissipation, thereby reducing heat loss from the reactor and lowering the heat load on the tubular furnace. The specific control process is as follows: 1) Fabricate insulation jackets. Insulation jackets are provided on the side walls and bottom outer sides of the reactor. The insulation jackets are fabricated in sections, with expansion joints left between each section. The expansion joints are filled with soft and elastic insulation material. A gap is left between the insulation jacket and the outer wall of the reactor. The upper and lower ends of the gap are sealed with insulation material to form a closed cavity. 2) The top of the reactor is independently insulated to meet the insulation requirements of the reactor top; 3) The flue gas pipeline is connected in series through flue gas pipes. The flue gas inlet of the lowest insulation jacket is connected to the flue gas outlet of the tubular furnace, and the flue gas outlet of the highest insulation jacket goes to the desulfurization and denitrification section through the air preheater. A bypass flue gas pipe is set between the flue gas inlet of the lowest insulation jacket and the flue gas outlet of the highest insulation jacket. During the asphalt modification process, the flue gas temperature at the outlet of the insulation jacket is controlled at 350-400℃.

7. The energy-saving method for heating modified asphalt in a tubular furnace according to claim 6, characterized in that, The power for the flow of flue gas inside the insulation jacket comes from the induced draft fan of the desulfurization and denitrification device, and the pressure inside the insulation jacket is -1 to -2 kPa.

8. The energy-saving method for heating modified asphalt in a tubular furnace according to claim 6, characterized in that, The outlet flue gas temperature of the insulation jacket is controlled by a differential pressure regulating valve on the bypass flue gas pipe. When the temperature is above 400°C, the differential pressure difference between the inlet and outlet of the differential pressure regulating valve is reduced, the differential pressure regulating valve is opened wider, the bypass flue gas flow rate is increased, and the flue gas flow rate of the insulation jacket is reduced. When the temperature is below 350°C, the differential pressure difference between the inlet and outlet of the differential pressure regulating valve is increased, the differential pressure regulating valve is opened less, the bypass flue gas flow rate is reduced, and the flue gas flow rate of the insulation jacket is increased.

Images