A high-temperature process gas heat recovery system and method

Abstract

This invention discloses a high-temperature process gas heat recovery system and method to solve the problem of unstable heat exchange efficiency and easy damage caused by ash accumulation in traditional waste heat boilers. The system includes a high-temperature process gas source and multiple waste heat boiler groups connected in series. Each waste heat boiler group includes one or more waste heat boilers connected in parallel. Each waste heat boiler includes: an outer cylinder; an inner cylinder disposed inside the outer cylinder, forming an evaporation chamber between the outer and inner cylinders, with an ash discharge pipe at the bottom of the inner cylinder; a process gas inlet pipe connected to the inner cylinder for introducing high-temperature process gas into the inner cylinder; a process gas outlet pipe, with its inlet end extending into the inner cylinder and its outlet end extending out of the waste heat boiler; and a flow-turbing component spirally disposed within the inner cylinder along its axis to guide the high-temperature process gas in a spiral flow within the inner cylinder. During the steam recovery process, the system automatically separates and discharges gases and some solid particles, reducing ash accumulation in the waste heat boilers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal chemical industry, and in particular to a high-temperature process gas heat recovery system and method. BACKGROUND

[0002] In the field of coal chemical industry, high-temperature ash-containing process gas of 500-750 DEG C is produced after coal gasification. A common way to recover the heat of high-temperature process gas is to pass the high-temperature process gas into a vertical fire-tube waste heat boiler or a water-tube waste heat boiler to recover the high-temperature preheating and simultaneously produce steam. However, since the high-temperature process gas after coal gasification contains a large amount of ash medium, when the waste heat boiler uses this high-temperature process gas to produce steam, the ash medium in the high-temperature process gas will deposit in the waste heat boiler, causing the fouling thermal resistance to rise and affecting the heat exchange efficiency of the waste heat boiler. The waste heat boiler needs to be frequently shut down for ash removal operation, affecting the production efficiency. Meanwhile, the ash deposition part is prone to damage, which will cause the reliability of the waste heat recovery device to decrease. SUMMARY

[0003] The present application aims to provide a high-temperature process gas heat recovery system and method to maintain the reliability of the waste heat boiler itself and the stability of the heat exchange efficiency.

[0004] To achieve the above-mentioned purpose, in a first aspect, the present application provides a high-temperature process gas heat recovery system, comprising a high-temperature process gas source and a plurality of groups of waste heat boilers connected in series with the high-temperature process gas source, each group of waste heat boilers comprising a single or multiple parallel waste heat boilers, each waste heat boiler comprising:

[0005] an outer cylinder, a cylinder wall of the outer cylinder being provided with a gas-liquid outlet and a water inlet;

[0006] an inner cylinder arranged inside the outer cylinder, an evaporation cavity being formed between the outer cylinder and the inner cylinder, the gas-liquid outlet and the water inlet both being in communication with the evaporation cavity, the bottom of the inner cylinder being provided with an ash removal pipe in communication with the inner cylinder, the ash removal pipe extending out of the outer cylinder;

[0007] a process gas inlet pipe arranged on the cylinder wall of the outer cylinder, the process gas inlet pipe being in communication with the inner cylinder, the process gas inlet pipe being used to pass high-temperature process gas provided by the high-temperature process gas source into the inner cylinder;

[0008] a process gas outlet pipe, an inlet end of the process gas outlet pipe extending into the inner cylinder, an outlet end of the process gas outlet pipe extending out of the inner cylinder and the outer cylinder;

[0009] a turbulence component arranged in the inner cylinder along the axis of the inner cylinder, used to guide the spiral flow of the high-temperature process gas in the inner cylinder.

[0010] With the above technical solution, the high-temperature process gas provided by the high-temperature process gas source is introduced into the multiple groups of waste heat boilers in series to exchange heat and produce steam and remove ash. The waste heat boiler with this structure can be made into an approximate standardized equipment. According to the flow of the high-temperature process gas of the high-temperature process gas source, the number of each group of waste heat boilers is determined. According to the temperature drop range of the high-temperature process gas, the number of groups of waste heat boilers in series is determined to recover the heat of the high-temperature process gas and generate steam. Since the high-temperature process gas enters the inner cylinder through the process gas inlet pipe of the waste heat boiler, it spirally descends along the axis of the inner cylinder under the guiding action of the flow disturbing part. In this process, part of the solid particles in the high-temperature process gas collide with the shell wall and gradually lose kinetic energy, sliding down the cylinder wall of the inner cylinder to the bottom. This process separates the gas and part of the solid particles in the high-temperature process gas. The separated part of the solid particles is discharged from the outside of the waste heat boiler through the ash discharge pipe at the bottom of the inner cylinder, and the separated gas is discharged to the outside of the waste heat boiler through the process gas outlet pipe. At the same time, the water entering the evaporation cavity between the inner cylinder and the outer cylinder through the water inlet is heated by the high-temperature process gas in the inner cylinder. The water in the evaporation cavity absorbs heat and evaporates to form a gas-liquid mixture of saturated water and saturated steam, which is discharged from the waste heat boiler through the gas-liquid outlet. The steam is finally obtained. As can be seen, in the process of using the high-temperature process gas to exchange heat and produce steam, the waste heat boiler can separate the gas and part of the solid particles in the high-temperature process gas containing a high amount of ash during the flow through the inner cylinder of the waste heat boiler. The separated solid particles are discharged from the waste heat boiler during normal operation of the waste heat boiler, reducing the ash deposition on the heat exchange surface of the waste heat boiler, thereby reducing the impact on the heat exchange efficiency of the waste heat boiler, reducing the frequency of ash removal operation of the waste heat boiler, reducing the impact on the normal production of the waste heat boiler, and improving the production efficiency of the waste heat boiler. At the same time, because the ash deposition is reduced, the reliability of the system operation is improved.

[0011] In some possible implementations, the flow disturbing part is a spiral flow disturbing plate, and an outer ring of the spiral flow disturbing plate is fixed to an inner wall of the inner cylinder.

[0012] An inner ring of the spiral flow disturbing plate is connected to an outer wall of the process gas outlet pipe.

[0013] In some possible implementations, the process gas outlet pipe is coaxially arranged with the inner cylinder.

[0014] In some possible implementations, a lower part of the inner cylinder is a tapered cylinder section with a diameter gradually decreasing from top to bottom, and the ash discharge pipe is in communication with a bottom outlet of the tapered cylinder section.

[0015] In some possible implementations, an inlet end of the process gas outlet pipe is arranged at a height position close to an upper edge of the tapered cylinder section.

[0016] In some possible implementations, the axis of the process gas inlet pipe is horizontally arranged, and the axis of the process gas inlet pipe is spaced apart from the axis of the inner cylinder in the horizontal direction.

[0017] In some possible implementations, the gas flow direction of the process gas inlet pipe is along the tangential direction of the inner wall of the inner cylinder.

[0018] In some possible implementations, the number of the waste heat boiler groups is 2-5, and the number of the waste heat boilers in each group is 1-10. In large-scale devices, a larger number of waste heat boilers can not be excluded.

[0019] In some possible implementations, the high-temperature process gas heat recovery system further comprises one or more gas-liquid separation tanks, the gas-liquid separation tank is provided with a steam outlet, the gas-liquid separation tank is used for gas-liquid separation, the steam outlet is used for leading out the steam obtained by gas-liquid separation; the gas-liquid separation tank is communicated with the gas-liquid outlet of the waste heat boiler through a gas-liquid conveying pipe.

[0020] In some possible implementations, each of the waste heat boilers is communicated with one of the gas-liquid separation tanks; or,

[0021] Each waste heat boiler in each group of waste heat boilers is communicated with one of the gas-liquid separation tanks, and the number of the waste heat boiler groups is equal to the number of the gas-liquid separation tanks.

[0022] In some possible implementations, the gas-liquid separation tank is further provided with a liquid outlet, and the liquid outlet is communicated with the water inlet through a liquid conveying pipe.

[0023] In some possible implementations, the inner wall of the inner cylinder is provided with a wear-resistant protective layer.

[0024] In some possible implementations, a steam superheater is further included, and the steam superheater is communicated with the steam outlet.

[0025] In some possible implementations, a boiler feed water preheater is further included, the boiler feed water preheater has a process gas inlet, a process gas outlet, a water inlet and a water outlet, the water outlet of the boiler feed water preheater is communicated with the gas-liquid separation tank, and the process gas outlet pipe of the group of waste heat boilers at the tail end is communicated with the process gas inlet of the boiler feed water preheater.

[0026] In some possible implementations, a Venturi scrubber and a low-pressure waste heat boiler are further included, the gas inlet of the Venturi scrubber is communicated with the process gas outlet of the boiler feed water preheater, and the gas outlet of the Venturi scrubber is communicated with the gas inlet of the low-pressure waste heat boiler.

[0027] In a second aspect, the present application further provides a high-temperature process gas heat recovery method, which uses the high-temperature process gas heat recovery system according to any one of the above aspects, and comprises the steps of:

[0028] S100, passing the high-temperature process gas of the high-temperature process gas source into the multiple groups of waste heat boiler groups connected in series to sequentially perform multiple heat exchanges and multiple ash removal treatments, to generate steam;

[0029] S200, passing the high-temperature process gas discharged from the waste heat boiler group at the tail into a boiler feed water preheater, heating the water in the boiler feed water preheater to a preset temperature, and passing the heated water into a gas-liquid separation tank through a feed water pipe, and further cooling the high-temperature process gas;

[0030] S300, passing the high-temperature process gas discharged from the boiler feed water preheater into a Venturi scrubber for washing, the temperature of the high-temperature process gas being reduced to a fifth temperature, and the steam in the high-temperature process gas being in a nearly saturated state;

[0031] S400, passing the washed high-temperature process gas into a low-pressure waste heat boiler for ash removal and cooling;

[0032] S500, discharging the high-temperature process gas after the ash removal and cooling by the low-pressure waste heat boiler.

[0033] In some possible implementation manners, the step S100 of passing the high-temperature process gas of the high-temperature process gas source into the multiple groups of waste heat boiler groups connected in series to sequentially perform multiple heat exchanges and multiple ash removal treatments to generate steam specifically comprises the steps of:

[0034] S101, passing the high-temperature process gas of the high-temperature process gas source into the first group of waste heat boiler groups to perform first heat exchange and first ash removal treatment to generate steam, and discharging the high-temperature process gas reduced to a first temperature;

[0035] S102, passing the high-temperature process gas at the first temperature into the second group of waste heat boiler groups to perform second heat exchange and second ash removal treatment to generate steam, and discharging the high-temperature process gas reduced to a second temperature;

[0036] S103, passing the high-temperature process gas at the second temperature into the third group of waste heat boiler groups to perform third heat exchange and third ash removal treatment to generate steam, and discharging the high-temperature process gas reduced to a third temperature.

[0037] In some possible implementation manners, the temperature of the high-temperature process gas discharged from the boiler feed water preheater in the step S200 is reduced to a fourth temperature. BRIEF DESCRIPTION OF DRAWINGS

[0038] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0039] Figure 1 A flow diagram of high-temperature process gas of a high-temperature process gas heat recovery system according to an embodiment of the present application;

[0040] Figure 2 A structural diagram of a waste heat boiler according to an embodiment of the present application;

[0041] Figure 3 A structural diagram of a group of waste heat boilers according to an embodiment of the present application.

[0042] Reference signs: A is a waste heat boiler, 1 is a gas-liquid separation tank, 101 is a steam outlet, 102 is a liquid outlet, 2 is a gas-liquid conveying pipe, 3 is a process gas outlet pipe, 4 is an outer cylinder, 401 is a gas-liquid outlet, 402 is a flange, 403 is a water inlet, 404 is an evaporation cavity, 5 is a process gas inlet pipe, 6 is an inner cylinder, 601 is a conical cylinder section, 602 is an ash discharge pipe, 7 is a turbulence component, 8 is a skirt, 9 is a liquid conveying pipe, 10 is a high-temperature process gas source, 11 is a boiler feed water preheater, 12 is a Venturi scrubber, and 13 is a low-pressure waste heat boiler. DETAILED DESCRIPTION

[0043] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0045] In addition, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited. The meaning of "several" is one or more, unless otherwise explicitly and specifically limited.

[0046] In the description of the present application, it is to be understood by those skilled in the art that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0047] In the description of the present application, it is to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0048] Reference is made to Figures 1-3The embodiment of the present application provides a high-temperature process gas heat recovery system, which comprises a high-temperature process gas source 10 and a plurality of groups of waste heat boilers connected in series with the high-temperature process gas source 10, each group of waste heat boilers comprising one or more waste heat boilers A connected in parallel; wherein each waste heat boiler A comprises an outer cylinder 4, an inner cylinder 6, a process gas inlet pipe 5, a process gas outlet pipe 3 and a turbulence component 7; wherein the axis of the outer cylinder 4 and the inner cylinder 6 is vertically arranged, the waste heat boiler A is a vertical waste heat boiler, and the cylinder wall of the outer cylinder 4 is provided with a gas-liquid outlet 401 and a water inlet 403. The inner cylinder 6 is arranged in the inner part of the outer cylinder 4 and is fixed, an annular evaporation cavity 404 is formed between the outer cylinder 4 and the inner cylinder 6, the gas-liquid outlet 401 and the water inlet 403 are both communicated with the evaporation cavity 404, the water inlet 403 is used for feeding water to be evaporated into the evaporation cavity 404, and the gas-liquid outlet 401 is used for discharging the saturated water and the saturated steam mixture obtained after evaporation in the evaporation cavity 404. The bottom of the inner cylinder 6 is provided with a dust discharge pipe 602 communicated with the inner cylinder 6, the dust discharge pipe 602 extends out of the bottom of the outer cylinder 4, and the dust discharge pipe 602 can be externally connected with a storage tank (not shown in the figure). The process gas inlet pipe 5 is arranged on the cylinder wall of the outer cylinder 4, one end of the process gas inlet pipe 5 penetrates through the outer cylinder 4 and is communicated with the inner cylinder 6, and the process gas inlet pipe 5 is used for feeding high-temperature process gas provided by the high-temperature process gas source 10 into the inner cylinder 6. The inlet end of the process gas outlet pipe 3 extends into the inner cylinder 6, the outlet end of the process gas outlet pipe 3 extends out of the inner cylinder 6 and the outer cylinder 4, and the process gas outlet pipe 3 is used for discharging the high-temperature process gas completing heat exchange in the inner cylinder 6 to the outside of the waste heat boiler A. Exemplarily, the lower end of the process gas outlet pipe 3 is the inlet end, and the upper end is the outlet end. The high-temperature process gas after heat exchange enters the process gas outlet pipe 3 from the lower end and is discharged from the process gas outlet pipe 3 from the upper end. The turbulence component 7 is spirally arranged in the inner cylinder 6 along the axis of the inner cylinder 6 and is used for guiding the high-temperature process gas to flow spirally in the inner cylinder 6.

[0049] The high-temperature process gas heat recovery system works, the high-temperature process gas provided by the high-temperature process gas source 10 is introduced into the multiple groups of waste heat boilers in turn for heat exchange and steam production and ash removal. The waste heat boiler A with this structure can be made into an approximate standardized equipment. According to the flow of the high-temperature process gas of the high-temperature process gas source, the number of each group of waste heat boilers is determined. According to the temperature drop range of the high-temperature process gas, the number of groups of waste heat boilers in series is determined to recover the heat of the high-temperature process gas and generate steam. The high-temperature process gas enters the inner cylinder 6 through the process gas inlet pipe 5. Under the guide of the flow disturbance part 7, the high-temperature process gas spirally descends along the axis of the inner cylinder 6. In this process, part of the solid particles in the high-temperature process gas collide with the shell wall and gradually lose kinetic energy, slide along the cylinder wall of the inner cylinder 6 to the bottom, and the process separates the gas and part of the solid particles in the high-temperature process gas. The separated part of the solid particles is discharged outside the waste heat boiler A through the ash discharge pipe 602 at the bottom of the inner cylinder 6 and can be collected in a storage tank. The separated gas is discharged to the outside of the waste heat boiler A after heat exchange through the process gas outlet pipe 3, or directly discharged, or connected to other required process flow. At the same time, the water in the evaporation cavity 404 between the inner cylinder 6 and the outer cylinder 4 enters through the water inlet 403. The water in the evaporation cavity 404 is heated and evaporated by the high-temperature process gas in the inner cylinder 6 to form a saturated water and saturated steam mixture. The steam-water mixture is discharged from the waste heat boiler A through the gas-liquid outlet 401, and finally the steam is obtained. The saturated steam produced is generally between 0.6-6 MPa, and steam with different pressures can also be produced according to actual needs.

[0050] It can be seen that in the process of using the waste heat boiler A to recover heat from the high-temperature process gas, the high-temperature process gas with a large amount of ash can separate the gas and part of the solid particles in the process of flowing through the inner cylinder 6 of the waste heat boiler A, so that part of the solid particles separated is discharged from the waste heat boiler A in the normal working process of the waste heat boiler A, reducing the ash deposition on the heat exchange surface of the waste heat boiler A, thereby reducing the influence on the heat exchange efficiency of the waste heat boiler A, ensuring the stability of the heat exchange efficiency of the waste heat boiler A, and reducing the frequency of the ash removal operation of the waste heat boiler A, reducing the influence on the normal production of the waste heat boiler A, and improving the production efficiency of the waste heat boiler A. At the same time, because the ash deposition is reduced, the reliability of the system operation is improved.

[0051] Exemplarily, the outer cylinder 4 can be a cylindrical structure, which includes an upper head, a straight cylinder segment and a lower head from top to bottom. The gas-liquid outlet 401 is arranged on the upper head of the outer cylinder 4, and the water inlet 403 is arranged on the lower head of the outer cylinder 4 or the side wall of the straight cylinder segment. In some examples, the water inlet 403 can be arranged on the lower side wall of the straight cylinder segment. Exemplarily, the process gas inlet pipe 5 is arranged on the upper side wall of the straight cylinder segment of the outer cylinder 4 and communicates with the upper position in the inner cylinder 6.

[0052] In the present embodiment, the number of waste heat boiler groups is 2-5 groups, for example, two groups, three groups, four groups, five groups, and more. The number of waste heat boilers A in each waste heat boiler group is 1-10, for example, one, two, three, four, five, six, seven, eight, nine, ten, and more. As shown in FIG. 1, Figure 1 and Figure 3 As shown in FIG. 1, the number of waste heat boiler groups is three, and the number of waste heat boilers A in each waste heat boiler group is three. Of course, the number of waste heat boiler groups in each group can be the same or different. The number of waste heat boiler groups in series and the number of waste heat boilers A in parallel in each group are selected according to the flow rate and temperature of the high-temperature process gas. In a large-scale device, a larger number of waste heat boilers A can be used.

[0053] In some embodiments, the turbulence component 7 is a spiral turbulence plate, which is spiral-shaped and has an inner circle and an outer circle with a diameter larger than that of the inner circle. The outer circle of the spiral turbulence plate is fixed to the inner wall of the inner cylinder 6, and the spiral turbulence plate and the inner wall of the inner cylinder 6 form a spiral airflow channel. After the high-temperature process gas enters the inner cylinder 6 at high speed, it spirally descends in the spiral airflow channel, causing some solid particles in the high-temperature process gas to gradually lose kinetic energy and slide along the inner wall of the inner cylinder 6 and the spiral turbulence plate to the bottom of the inner cylinder 6. For example, the outer edge of the spiral turbulence plate can be sealingly connected to the inner wall of the inner cylinder 6, and there is no gap between the outer edge of the spiral turbulence plate and the inner wall of the inner cylinder 6, so that the separated solid particles slide along the inner wall of the inner cylinder 6 and the spiral turbulence plate. Of course, there can be a gap between the outer edge of the spiral turbulence plate and the inner wall of the inner cylinder 6, which can be connected by discrete connectors, so that the separated solid particles can directly slide vertically along the inner wall of the inner cylinder 6, and the separation speed is faster.

[0054] In some embodiments, the inner circle of the spiral turbulence plate is connected to the outer wall of the process gas outlet pipe 3. The spiral turbulence plate is fixed to the process gas outlet pipe 3 through the inner circle, and the inner edge of the spiral turbulence plate is sealingly connected to the outer wall of the process gas outlet pipe 3, or there can be a gap between them, which can be connected by discrete connectors. At the same time, the outer circle of the spiral turbulence plate can be connected to the inner wall of the inner cylinder 6 or not. As long as the spiral turbulence plate can make the high-temperature process gas move spirally, it is not limited to the connection form listed in the present embodiment.

[0055] Of course, in addition to continuous spiral baffles, the baffle component 7 can also be multiple short baffles arranged intermittently along the spiral direction. The multiple short baffles arranged along the spiral direction can also guide the high-temperature process gas in the spiral direction, thereby achieving the separation of solid particles in the high-temperature process gas.

[0056] In some embodiments, the process gas outlet pipe 3 is coaxially arranged with the inner cylinder. This arrangement makes the flow cross section of the turbulence component 7 the same in the circumferential direction, and the spiral flow velocity of the high-temperature process gas is more uniform and stable at various positions in the circumferential direction. It also makes it less likely that the separated solid particles will be deposited on the inner wall of the inner cylinder 6 or the turbulence component 7 due to differences in gas flow velocity.

[0057] Furthermore, such as Figure 2 As shown, in some embodiments, the lower part of the inner cylinder 6 is a tapered section 601 that narrows from top to bottom, and the ash discharge pipe 602 is connected to the bottom outlet of the tapered section 601. That is, the inner cylinder 6 is connected by an upper cylindrical section and a lower tapered section 601. The diameter of the cylindrical section and the upper diameter of the tapered section 601 can be the same or different. By setting the lower part of the inner cylinder 6 as a tapered section 601 that is larger at the top and smaller at the bottom, after the high-temperature process gas enters the inner cylinder 6, it spirals downward from top to bottom. When the high-temperature process gas flows to the tapered section 601, it spirals upward in the opposite direction under the action of the inner wall of the tapered section 601, so that the high-temperature process gas enters the process gas outlet pipe 3 located at the center of the inner cylinder 6. This makes the flow path of the separated gas more clearly separated from the flow path of the solid particles, reduces the re-mixing of the separated solid particles and gas, and is more conducive to the separation of solid particles.

[0058] In some examples, the taper of the conical section 601 is 5° to 30°, meaning the angle between the generatrix of the inner wall surface of the conical section 601 and the axis is 5° to 30°, specifically 5°, 8°, 10°, 15°, 19°, 23°, 27°, 30°, etc. Within this taper range, the reverse spiral ascent of the high-temperature process gas can be effectively achieved. If the taper is too small, the reverse spiral ascent effect is poor; if the taper is too large, the sliding effect of solid particles is poor, and they easily deposit on the inner wall of the conical section 601.

[0059] Furthermore, in this embodiment, the inlet end of the process gas outlet pipe 3 is positioned close to the height of the upper edge of the conical section 601. That is, the process gas outlet pipe 3 is coaxially arranged with the inner cylinder 6, and the lower end of the process gas outlet pipe 3 is the inlet end. The lower end of the process gas outlet pipe 3 is positioned slightly higher than the height of the upper edge of the conical section 601. This allows the high-temperature process gas, which is spiraling upwards in the opposite direction, to travel the shortest possible distance to enter the process gas outlet pipe 3 when it enters the conical section 601, thus reducing interference with the spiraling downward-moving high-temperature process gas.

[0060] Exemplarily, the inner cylinder 6 can also be a cylindrical segment as a whole. By reasonably setting the position and direction of the inlet end and outlet end of the process gas outlet pipe 3, such as setting the inlet end of the process gas outlet pipe 3 on the side wall of the inner cylinder 6 and making the process gas outlet pipe 3 tilt upward to extend out of the waste heat boiler A, the separated gas can enter the process gas outlet pipe 3 through the inlet end of the process gas outlet pipe 3 on the side wall of the inner cylinder 6 after the high-temperature process gas spirally descends, and is discharged by being guided upward, while the separated solid particles continue to slide down along the inner wall of the inner cylinder 6 due to their own gravity, so as to realize the separation of part of the solid particles. As long as the high-temperature process gas can reduce the ash deposition on the heat exchange surface in the inner cylinder 6 during the heat exchange in the inner cylinder 6 and reduce the influence on the heat exchange efficiency of the waste heat boiler A, it is not limited to the structure form listed in the embodiment.

[0061] In some embodiments, the axis of the process gas inlet pipe 5 is horizontally arranged, and there is a spacing in the horizontal direction between the axis of the process gas inlet pipe 5 and the axis of the inner cylinder 6. That is, the axis of the process gas inlet pipe 5 is horizontally arranged and offset from the axis of the inner cylinder 6, so that after the introduced high-temperature process gas enters the inner cylinder 6, the gas flow is not directly through the axis of the inner cylinder 6, and thus the gas flow is not perpendicular to the inner wall of the inner cylinder 6, the resistance received is reduced, the influence on the speed of the gas flow is small, and the high-temperature process gas can be more smoothly guided to descend in the spiral direction, so as to realize the separation effect of the gas and the solid particles in the high-temperature process gas.

[0062] Further, in the embodiment, the gas flow direction of the process gas inlet pipe 5 is along the tangential direction of the inner wall of the inner cylinder 6. That is, the flow direction of the high-temperature process gas entering the inner cylinder 6 is tangent to the inner wall of the inner cylinder 6, so as to further reduce the loss of the flow rate of the high-temperature process gas, make the high-temperature process gas spirally descend at high speed, and improve the separation effect of the gas and the solid particles in the high-temperature process gas.

[0063] In some possible implementations, such as Figure 2 and Figure 3As shown, the high-temperature process gas heat recovery system further comprises one or more gas-liquid separation tanks 1, which are arranged outside the waste heat boiler A, and are provided with steam outlets 101. The gas-liquid outlets 401 of the outer cylinder 4 are communicated with the gas-liquid separation tanks 1 through gas-liquid conveying pipes 2. The gas-liquid separation tanks 1 are used for gas-liquid separation, and the steam outlets 101 are used for discharging the saturated steam obtained by gas-liquid separation. Exemplarily, the gas-liquid separation tanks 1 are located above the outer cylinder 4. The steam in the steam chamber 404 is evaporated to form a saturated water and saturated steam mixture. Therefore, the saturated water and saturated steam mixture enters the gas-liquid separation tank 1 through the gas-liquid conveying pipe 2. The saturated water and saturated steam mixture is separated in the gas-liquid separation tank 1 to obtain saturated water and saturated steam. The saturated water obtained by separation is left in the gas-liquid separation tank 1, and the saturated steam obtained by separation is discharged from the steam outlet 101. The discharged saturated steam can be used in other processes or collected. It should be noted that the separation structure of the saturated water and saturated steam is a mature technology, which will not be described in detail here. Exemplarily, the gas-liquid separation tank can be a steam drum, which is provided with a gas-liquid separation structure.

[0064] Further, in the embodiment, each waste heat boiler A is communicated with one gas-liquid separation tank 1, that is, all waste heat boilers A share one gas-liquid separation tank 1; or, each waste heat boiler A in each waste heat boiler group is communicated with one gas-liquid separation tank 1, and the number of waste heat boiler groups is equal to the number of gas-liquid separation tanks 1, that is, each waste heat boiler group shares one gas-liquid separation tank 1.

[0065] Specifically, when the gas-liquid separation tank 1 is one, the gas-liquid outlets of each waste heat boiler A are communicated with the gas-liquid separation tank 1 through the gas-liquid conveying pipes 2.

[0066] When the gas-liquid separation tank 1 is multiple, and the number is equal to the number of waste heat boiler groups, the gas-liquid outlets 401 of each waste heat boiler A in each waste heat boiler group are communicated with the same gas-liquid separation tank 1 through the gas-liquid conveying pipes 2.

[0067] As long as the saturated water and saturated steam mixture generated by the waste heat boiler A can be collected and subjected to gas-liquid separation, it is not limited to the combination form of the gas-liquid separation tank 1 listed in the above embodiment.

[0068] Further, in the embodiment, the gas-liquid separation tank 1 is further provided with a liquid outlet 102, which is communicated with the water inlet 403 on the outer cylinder 4 through a liquid conveying pipe 9.

[0069] In some possible implementations, the inner wall of the inner cylinder 6 is provided with a wear-resistant protective layer. Because the high-temperature process gas containing a large amount of ash enters the inner cylinder 6 at high speed and descends in a spiral direction, solid particles will wear down the inner wall of the inner cylinder 6. Therefore, providing a wear-resistant protective layer on the inner wall can improve the wear resistance of the inner cylinder 6 and prevent it from wearing through. For example, the wear-resistant protective layer can be made of wear-resistant alloy steel. Wear-resistant alloy steel is a mature technology and will not be described in detail here.

[0070] For example, the outer cylinder 4 can be divided into upper and lower sections, which are detachably assembled via flange 402, facilitating the insertion of the inner cylinder 6 into the outer cylinder 4. A skirt 8 is provided at the waist of the outer cylinder 4 to support and fix the entire waste heat boiler A.

[0071] In this embodiment, the high-temperature process gas heat recovery system also includes a steam superheater (not shown in the figure), which is connected to the steam outlet 101 of the gas-liquid separator 1. Steam generated after passing through multiple waste heat boiler units is introduced into the steam superheater from the gas-liquid separator 1, where it is superheated to 30°C–70°C above its saturation temperature. The superheated steam is generally used in the gasification furnace, but can also be used for other purposes. The heat of the steam superheater comes from external heating equipment, or it can utilize the heat from the high-temperature process gas in this system.

[0072] like Figure 1 As shown, in this embodiment, the high-temperature process gas heat recovery system also includes a boiler feedwater preheater 11. The boiler feedwater preheater 11 has a process gas inlet, a process gas outlet, a water inlet, and a water outlet. The water outlet of the boiler feedwater preheater 11 is connected to the gas-liquid separator 1. The process gas outlet pipe 3 of a group of waste heat boilers located at the end of the series is connected to the process gas inlet of the boiler feedwater preheater 11. When external boiler water is needed to supplement the waste heat boiler A for evaporation, the supplied water is usually demineralized water with a low temperature, significantly different from the saturated water temperature (typically 104℃). This can easily lead to under-enthalpy during heat exchange at the waste heat boiler's heat exchange surface. Therefore, the temperature of the demineralized water needs to be increased to minimize the temperature difference with the saturated water. In operation, the demineralized water is introduced into the boiler feedwater preheater 11 through the inlet. Simultaneously, high-temperature process gas, after heat exchange and ash removal by multiple waste heat boiler groups, enters the boiler feedwater preheater 11 through the process gas inlet. The high-temperature process gas heats the demineralized water to a suitable temperature of 150℃–220℃. The heated boiler feedwater is then discharged from the boiler feedwater preheater 11 through the outlet and replenished into the gas-liquid separator 1 for steam recycling. The high-temperature process gas in the boiler feedwater preheater 11 is discharged from the process gas outlet, further recovering the heat from the high-temperature process gas.

[0073] In some embodiments, the high-temperature process gas heat recovery system further comprises a venturi scrubber 12 and a low-pressure waste heat boiler 13, the gas inlet of the venturi scrubber 12 is communicated with the process gas outlet of the boiler feed water preheater 11, and the gas outlet of the venturi scrubber 12 is communicated with the gas inlet of the low-pressure waste heat boiler 13. In use, the high-temperature process gas discharged from the boiler feed water preheater 11 is introduced into the venturi scrubber 12 for washing and cooling, and further dust removal, at this time, the high-temperature process gas after washing contains a large amount of water vapor, and the water vapor therein is in a nearly saturated state. The high-temperature process gas after washing enters the low-pressure waste heat boiler 13, further recovers the heat of the high-temperature process gas, and generates steam in the low-pressure waste heat boiler 13. The low-pressure waste heat boiler 13 is different from the waste heat boiler A in the system, and belongs to a conventional and mature waste heat boiler.

[0074] Based on the high-temperature process gas heat recovery system described in any of the above embodiments, the present embodiment further provides a high-temperature process gas heat recovery method, which uses the high-temperature process gas heat recovery system described in any of the above embodiments, and comprises the following steps:

[0075] Step S100: introducing the high-temperature process gas of the high-temperature process gas source 10 into the multiple groups of waste heat boiler groups connected in series to perform multiple heat exchanges and multiple dust removals in sequence, and generating steam. Most of the heat of the high-temperature process gas is recovered and utilized.

[0076] Step S200: introducing the high-temperature process gas discharged from the group of waste heat boiler groups at the tail into the boiler feed water preheater 11, heating the water in the boiler feed water preheater 11 to a preset temperature, for example, the preset temperature can be 150-220℃, and introducing the heated water into the gas-liquid separation tank 1 through the feed water pipe, and further cooling the high-temperature process gas. The high-temperature process gas after heat exchange and dust removal in the multiple groups of waste heat boiler groups is used to further heat the water for boiler evaporation, and further recover the heat of the high-temperature process gas.

[0077] Step S300: introducing the high-temperature process gas discharged from the boiler feed water preheater 11 into the venturi scrubber 12 for washing, and reducing the temperature of the high-temperature process gas to a fifth temperature, for example, the fifth temperature is 180-220℃, and the steam in the high-temperature process gas is in a nearly saturated state. This step further performs dust removal and cooling on the high-temperature process gas.

[0078] Step S400: introducing the high-temperature process gas after washing into the low-pressure waste heat boiler 13 for dust removal and cooling. In the low-pressure waste heat boiler 13, the pressure of the saturated water and the saturated steam side is less than the steam partial pressure of the process gas side of the low-pressure waste heat boiler 13 and there is a certain difference, the water vapor component in the process gas is condensed and releases heat, the saturated water in the low-pressure waste heat boiler 13 absorbs heat to generate steam from the saturated water of the saturated steam side, and further recovers the heat of the high-temperature process gas.

[0079] Step S500, the high temperature process gas after the low pressure waste heat boiler 13 ash cooling is discharged. Discharge to other process flow or save or environmental protection treatment after discharge.

[0080] In some embodiments, the high temperature process gas of the high temperature process gas source 10 in step S100 is sequentially introduced into the multiple groups of waste heat boiler groups in series to sequentially carry out multiple heat exchange and multiple ash removal treatment, and steam is generated, specifically including steps:

[0081] Step S101, the high temperature process gas of 500-750℃ of the high temperature process gas source 10, for example, the temperature of the high temperature process gas is 720℃, is introduced into the first group of waste heat boiler groups to carry out the first heat exchange and the first ash removal treatment, generate steam, and discharge the high temperature process gas reduced to the first temperature, for example, the first temperature can be 480-530℃, preferably, the temperature of the discharged high temperature process gas is about 500℃;

[0082] Step S102, the high temperature process gas of 480-530℃ is introduced into the second group of waste heat boiler groups to carry out the second heat exchange and the second ash removal treatment, generate steam, and discharge the high temperature process gas reduced to the second temperature, for example, the second temperature can be 390-430℃, preferably, the temperature of the discharged high temperature process gas is about 410℃;

[0083] Step S103, the high temperature process gas of 390-430℃ is introduced into the third group of waste heat boiler groups to carry out the third heat exchange and the third ash removal treatment, generate steam, and discharge the high temperature process gas reduced to the third temperature. For example, the third temperature can be 340-350℃, preferably, the temperature of the discharged high temperature process gas is 350℃.

[0084] Further, in the present embodiment, the temperature of the high temperature process gas discharged by the boiler feed water preheater in step S200 is reduced to the fourth temperature, for example, the fourth temperature can be 240-280℃, preferably, the temperature of the high temperature process gas is 260℃.

[0085] In some embodiments, between step S100 and step S200, there is also a step of introducing the steam produced by the multiple groups of waste heat boiler groups into a steam superheater to carry out heating, obtaining superheated steam, and the temperature of the superheated steam is superheated to 30-70℃ above the saturation temperature; the superheated steam is generally used in the gasification furnace, and can also be used for other purposes. The heat used by the superheated steam can come from external heating equipment, or from the heat of the high temperature process gas of the system.

[0086] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0087] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A high temperature process gas heat recovery system characterized by, The high-temperature process gas heat recovery system comprises a high-temperature process gas source and a plurality of groups of waste heat boilers connected in series with the high-temperature process gas source, each group of waste heat boilers comprising one or more waste heat boilers connected in parallel, each waste heat boiler comprising: An outer cylinder, a cylinder wall of the outer cylinder being provided with a gas-liquid outlet and a water inlet; An inner cylinder arranged inside the outer cylinder, an evaporation cavity being formed between the outer cylinder and the inner cylinder, the gas-liquid outlet and the water inlet being communicated with the evaporation cavity, the bottom of the inner cylinder being provided with an ash discharge pipe communicated with the inner cylinder, the ash discharge pipe extending out of the outer cylinder, the lower part of the inner cylinder being a tapered cylinder section tapering from top to bottom, the ash discharge pipe being communicated with the bottom outlet of the tapered cylinder section; A process gas inlet pipe arranged on the cylinder wall of the outer cylinder, the process gas inlet pipe being communicated with the inner cylinder, the process gas inlet pipe being used for introducing high-temperature process gas provided by the high-temperature process gas source into the inner cylinder; A process gas outlet pipe, an inlet end of the process gas outlet pipe extending into the inner cylinder, an outlet end of the process gas outlet pipe extending out of the inner cylinder and the outer cylinder, the inlet end of the process gas outlet pipe being arranged at a height position close to the upper edge of the tapered cylinder section; A turbulence component arranged in the inner cylinder along the axis of the inner cylinder, the turbulence component being used for guiding the high-temperature process gas to flow spirally in the inner cylinder, the turbulence component being a spiral turbulence plate, an outer ring of the spiral turbulence plate being fixed to the inner wall of the inner cylinder. The high-temperature process gas heat recovery system further comprises one or more gas-liquid separation tanks, the gas-liquid separation tanks being provided with steam outlets, the gas-liquid separation tanks being used for gas-liquid separation, the steam outlets being used for guiding the steam obtained by gas-liquid separation out, the gas-liquid separation tanks being communicated with the gas-liquid outlets of the waste heat boilers through gas-liquid conveying pipes.

2. The high-temperature process gas heat recovery system according to claim 1, wherein An inner ring of the spiral turbulence plate is connected with an outer wall of the process gas outlet pipe.

3. The high temperature process gas heat recovery system of claim 1, wherein, The process gas outlet pipe is arranged coaxially with the inner cylinder.

4. The high temperature process gas heat recovery system of claim 1, wherein, An axis of the process gas inlet pipe is arranged horizontally, and there is a spacing between the axis of the process gas inlet pipe and the axis of the inner cylinder in the horizontal direction.

5. The high temperature process gas heat recovery system of claim 1, wherein, The number of groups of waste heat boilers is 2-5, and the number of waste heat boilers in each group of waste heat boilers is 1-10.

6. The high temperature process gas heat recovery system of claim 1, wherein, Each of the waste heat boilers is communicated with one of the gas-liquid separation tanks; or Each of the waste heat boilers in each group of waste heat boilers is communicated with one of the gas-liquid separation tanks, and the number of groups of waste heat boilers is equal to the number of gas-liquid separation tanks.

7. The high temperature process gas heat recovery system of claim 1, wherein, The gas-liquid separation tank is further provided with a liquid outlet, and the liquid outlet is communicated with the water inlet through a liquid conveying pipe.

8. The high temperature process gas heat recovery system of claim 1, wherein, The high-temperature process gas heat recovery system further comprises a steam superheater communicated with the steam outlet.

9. The high temperature process gas heat recovery system of claim 1, wherein, The high-temperature process gas heat recovery system further comprises a boiler feed water preheater having a process gas inlet, a process gas outlet, a water inlet and a water outlet, the water outlet of the boiler feed water preheater being communicated with the gas-liquid separation tank, and the process gas outlet pipe of the group of waste heat boilers at the tail end being communicated with the process gas inlet of the boiler feed water preheater.

10. The high temperature process gas heat recovery system of claim 9, wherein, A Venturi scrubber is also included, with its inlet communicating with the process gas outlet of the boiler feed water preheater, and its outlet communicating with the inlet of the low-pressure waste heat boiler.

11. A method of heat recovery from a high temperature process gas, characterized by, The high-temperature process gas heat recovery system according to any one of claims 1-10, comprising the steps of: S100, passing the high-temperature process gas from the high-temperature process gas source into a plurality of waste heat boiler groups connected in series to sequentially perform multiple heat exchanges and multiple ash removal treatments, to generate steam; S200, passing the high-temperature process gas discharged from the waste heat boiler group at the tail into a boiler feed water preheater, heating the water in the boiler feed water preheater to a preset temperature, and passing the heated water into a gas-liquid separation tank through a feed water pipe, and further cooling the high-temperature process gas; S300, passing the high-temperature process gas discharged from the boiler feed water preheater into a Venturi scrubber for washing, the temperature of the high-temperature process gas being reduced to a fifth temperature, to generate approximately saturated steam; S400, passing the washed high-temperature process gas into a low-pressure waste heat boiler for ash removal and cooling; S500, discharging the high-temperature process gas after ash removal and cooling by the low-pressure waste heat boiler.

12. The high temperature process gas heat recovery method of claim 11, wherein, The step S100 of passing the high-temperature process gas from the high-temperature process gas source into a plurality of waste heat boiler groups connected in series to sequentially perform multiple heat exchanges and multiple ash removal treatments to generate steam specifically comprises the steps of: S101, passing the high-temperature process gas from the high-temperature process gas source into a first waste heat boiler group to perform a first heat exchange and a first ash removal treatment, to generate steam, and discharge the high-temperature process gas reduced to a first temperature; S102, passing the high-temperature process gas at the first temperature into a second waste heat boiler group to perform a second heat exchange and a second ash removal treatment, to generate steam, and discharge the high-temperature process gas reduced to a second temperature; S103, passing the high-temperature process gas at the second temperature into a third waste heat boiler group to perform a third heat exchange and a third ash removal treatment, to generate steam, and discharge the high-temperature process gas reduced to a third temperature.

13. The high temperature process gas heat recovery method of claim 11, wherein, The temperature of the high-temperature process gas discharged from the boiler feed water preheater in the step S200 is reduced to a fourth temperature.

Images