High-temperature fluid transporting pipeline with heat exchange apparatus installed therein, suitable heat exchange apparatus and heat exchange method

Abstract

The present invention discloses a high-temperature fluid transporting pipeline with a heat exchange apparatus installed therein, a suitable heat exchange apparatus and a heat exchange method, wherein heat contained in a high-temperature fluid can be recovered during the transportation thereof. The heat exchange apparatus comprises a heat exchange body inserted into the high-temperature fluid transporting pipeline, and a heat-receiving fluid coil installed therein. The method of heat exchange is that the high-temperature fluid heats an auxiliary fluid in a heat exchange cavity via a heat exchange panel of the heat exchange body in contact therewith, and the heated auxiliary fluid then conducts the heat to a heat-receiving fluid in the heat-receiving fluid coil. As an example, the high-temperature fluid is flue gas generated by combustion, the heat exchange apparatus of the present invention is inserted into a flue gas transporting pipeline, the auxiliary fluid is an inert gas such as air, and the air heated indirectly by the high-temperature flue gas conducts heat to fuel and/or oxygen-enriched gas (serving as an oxidant/combustion aid) flowing in the heat-receiving fluid coil.

Claims

1. A method for using a high-temperature fluid in a transporting pipeline to heat a heat-receiving fluid, comprising: a) providing a heat exchange apparatus, the heat exchange apparatus comprising a heat exchange body located completely within the transporting pipeline, and a heat-receiving fluid inlet pipeline, a heat-receiving fluid outlet pipeline, an auxiliary fluid inlet pipeline and an auxiliary fluid outlet pipeline, which all extend out of a casing of the transporting pipeline; the heat exchange body comprises a heat exchange cavity enclosed by a heat exchange panel, and a heat-receiving fluid coil is installed in the heat exchange cavity; wherein an installation hole is provided in the casing of the transporting pipeline, the heat exchange body of the heat exchange apparatus is inserted into the interior of the transporting pipeline through the installation hole, a gap between the heat exchange apparatus and the installation hole is sealed using a sealing refractory material, and a supporting structure is further included outside the transporting pipeline for the purpose of supporting the heat exchange apparatus, and b) providing a heat-receiving fluid and an auxiliary fluid, wherein the heat-receiving fluid flows in the heat-receiving fluid coil, the auxiliary fluid flows or is stationary in the heat exchange cavity, and the heat-receiving fluid is heated by the high-temperature fluid through heat conduction by the auxiliary fluid and heat radiation by the heat exchange panel.

2. The method according to claim 1, wherein the high-temperature fluid comprises flue gas generated by combustion and/or thermal cracking.

3. The method according to claim 1, wherein the auxiliary fluid comprises one of air, N.sub.2 and CO.sub.2 or a combination of more than one thereof, and the heat-receiving fluid comprises O.sub.2, natural gas or other fuel gases.

4. The method according to claim 2, wherein the temperature range of the flue gas is 500-1200? C., and the temperature range of the heat-receiving fluid is 300-600? C.

5. The method according to claim 1, wherein the range of flow rate of the heat-receiving fluid is 5-100 m/s and the range of flow rate of the auxiliary fluid is 0-50 m/s.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings in the present disclosure merely serve to illustrate the present invention, such that the spirit of the present invention can be understood and explained, but do not limit the present invention in any respect.

(2) FIG. 1 is a three-dimensional structural drawing of a heat exchange apparatus.

(3) FIG. 2 is a sectional drawing of the heat exchange apparatus after installation on the high-temperature fluid transporting pipeline.

LIST OF REFERENCE SYMBOLS

(4) FIGS. 1-2 are embodiments according to the present invention, wherein identical references represent corresponding parts in the two figures. Key to the drawings: 1heat exchange body, 2heat-receiving fluid inlet pipeline, 3heat-receiving fluid outlet pipeline, 4auxiliary fluid inlet pipeline, 5auxiliary fluid outlet pipeline, 6heat exchange panel, 7heat exchange cavity, 8heat-receiving fluid coil, 9temperature sensor, 10primary heat-receiving fluid inlet distributor, 11primary heat-receiving fluid outlet distributor, 12auxiliary fluid inlet distributor, 13auxiliary fluid outlet distributor, 14secondary heat-receiving fluid inlet distributor, 15secondary heat-receiving fluid outlet distributor, 16auxiliary fluid inlet branch pipe, 17auxiliary fluid outlet branch pipe, 18gas component analyser, 20installation hole, 21refractory bricks, 22transporting pipeline casing, 23sealing refractory material, 25high-temperature fluid transporting pipeline.

Notations and Nomenclature

(5) In the present invention, it should be understood that orientational or positional relationships indicated by terms such as up, down, front, rear, perpendicular, parallel, top, bottom, inner and outer are based on the orientational or positional relationships shown in the drawings, and use a horizontal plane as a reference.

(6) Unless otherwise stated, qualifiers similar to a appearing herein do not indicate a definition of quantity, but describe technical features distinguished from one another. Similarly, modifiers similar to about and approximately appearing in front of numerals herein generally include the number itself, and the specific meaning thereof should be understood in conjunction with the meaning of the context. Unless modified by a specific quantifying measure word, nouns herein should be regarded as including both singular and plural forms, i.e. the technical solution may include a single one of the technical feature concerned, but may also include a plurality of the technical feature.

(7) In the present invention, unless otherwise clearly specified and defined, terms such as installed, connected together, connected, in communication and fixed should be understood in a broad sense, e.g. may mean connected in a fixed manner, but may also mean removably connected, or forming a single piece; may mean mechanically connected; may mean directly connected together, but may also mean connected indirectly via an intermediate medium; and may mean internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

(8) The high-temperature fluid in the present invention may have various forms and compositions, including gases as well as liquids; and may be a single component or a mixture. High-temperature means that the temperature thereof is higher than the temperature of the fluid being heated, with a range of variation of 100-1500? C. When the high-temperature fluid is a gas such as flue gas, the pipeline for transporting same is generally formed of refractory bricks; when the high-temperature fluid is a liquid, the casing of the pipeline for transporting same is often formed of metal. The present invention is suitable for the modification of various high-temperature fluid transporting pipelines arranged substantially horizontally. In the process of modification, an installation hole is made in a part of the pipeline that lies above a horizontal plane through the central axis, and a heat exchange body of the heat exchange apparatus of the present invention is inserted into the interior of the transporting pipeline through the installation hole.

DESCRIPTION OF PREFERRED EMBODIMENTS

(9) As shown in FIG. 1, the heat exchange apparatus of the present invention comprises a heat exchange body 1 that extends completely into a high-temperature fluid transporting pipeline 25; an entire outer surface of the heat exchange body 1 is formed by a heat exchange panel 6 suitable for conducting heat, the heat exchange panel 6 enclosing a hermetic heat exchange cavity 7, with a heat-receiving fluid coil 8 being installed in the heat exchange cavity 7. The heat-receiving fluid coil 8 is not in direct contact with the heat exchange panel 6. The heat-receiving fluid coil 8 can be helically coiled, or folded back and forth. In FIG. 1, the heat exchange body 1 has a hollow annular structure; the high-temperature fluid not only comes into contact with the heat exchange panel 6 along a periphery of the heat exchange body 1, but can also pass through the space in the middle, transferring heat to the heat exchange panel 6. The heat-receiving fluid coil 8 is coiled helically in the heat exchange cavity 7 with the central axis of the annular structure as a middle axis, and with the rings fitted against each other as closely as possible. This design has the advantages of a large heat exchange area and high heat exchange efficiency. A secondary heat-receiving fluid inlet distributor 14, a secondary heat-receiving fluid outlet distributor 15, an auxiliary fluid inlet branch pipe 16 and an auxiliary fluid outlet branch pipe 17 are separately connected to the top of the heat exchange body 1. The greater parts of the secondary distributors and branch pipes extend out of a casing 22 of the high-temperature fluid transporting pipeline 25, and are connected to other pipelines, distributors, etc. via structures such as flanges and screws.

(10) The various parts mentioned above are manufactured by a method of integral forming or welding, and are installed in one piece. Specifically, an installation hole 20 is made at the top of the substantially horizontally arranged high-temperature fluid transporting pipeline 25; if this is a high-temperature flue gas pipeline formed of refractory bricks 21, then some of the refractory bricks 21 at the top thereof are removed. The heat exchange body 1 is inserted into the interior of the high-temperature fluid transporting pipeline 25 through the installation hole 20, and a sealing refractory material 23 such as ceramic fiber, glass fiber or refractory mortar is stuffed into a gap at the installation hole to achieve sealing. These materials also serve to provide thermal isolation and limit shifting of the heat exchange body 1. One end of the secondary heat-receiving fluid inlet distributor 14 is connected via a flange to a primary heat-receiving fluid inlet distributor 10 and a heat-receiving fluid inlet pipeline 2; one end of the secondary heat-receiving fluid outlet distributor 15 is connected via a flange to a primary heat-receiving fluid outlet distributor 11 and a heat-receiving fluid outlet pipeline 3. The auxiliary fluid inlet branch pipe 16 is connected to an auxiliary fluid inlet distributor 12 and an auxiliary fluid inlet pipeline 4; the auxiliary fluid outlet branch pipe 17 is connected to an auxiliary fluid outlet distributor 13 and an auxiliary fluid outlet pipeline 5. Those parts which extend out of the high-temperature fluid transporting pipeline are wrapped in a material such as blanket insulation, sponge insulation or rubber insulation (not shown in the figures) to reduce heat dissipation, and are kept stable by a supporting structure (not shown in the figures). The supporting structure can be fixed to the high-temperature fluid transporting pipeline 25 or the floor.

(11) A temperature sensor 9 is optionally installed on the heat-receiving fluid outlet pipeline 3 or the heat-receiving fluid outlet distributor (15 or 11). Outside the heat exchange apparatus, a heat-receiving fluid delivery system (not shown in the figures) connected to the heat-receiving fluid inlet pipeline 2 and the heat-receiving fluid outlet pipeline 3 is also included. The system comprises, inter alia, a heat-receiving fluid controller and a valve capable of adjusting the flow rate of the heat-receiving fluid. The heat-receiving fluid controller can receive a heat-receiving fluid outlet temperature from the temperature sensor 9, and on this basis can adjust the flow rate (or flow speed), temperature and pressure, etc. of the heat-receiving fluid.

(12) Outside the heat exchange apparatus, an auxiliary fluid delivery system connected to the auxiliary fluid inlet pipeline 4 and the auxiliary fluid outlet pipeline 5 is also included. The system comprises, inter alia, an auxiliary fluid controller and a valve capable of adjusting the flow rate of the auxiliary fluid (not shown in the figures). The auxiliary fluid flows within the heat exchange cavity 7, in a space outside the heat-receiving fluid coil 8. The auxiliary fluid controller can also receive a heat-receiving fluid outlet temperature from the temperature sensor 9, and on this basis can adjust the flow rate (or flow speed), temperature and pressure, etc. of the auxiliary fluid.

(13) The heat exchange apparatus of the present invention adopts a method of indirect heat exchange. High-temperature fluid in the transporting pipeline first heats the heat exchange panel 6 by conduction, radiation and convection, etc.; the heat exchange panel 6 then heats the auxiliary fluid in contact therewith by conduction and radiation, etc. The heated auxiliary fluid flows or is stationary around the heat-receiving fluid coil 8, and thus further conducts heat to the heat-receiving fluid in the coil. When the heat-receiving fluid comprises a substance that is reactive, corrosive or otherwise dangerous at high temperatures, e.g. O.sub.2, CH.sub.4, etc., the use of indirect heat exchange greatly increases the safety of the heat exchange process. This is because inert air, steam, N.sub.2 or CO.sub.2, etc. can be chosen as the auxiliary fluid, and the heat exchange panel 6 is not likely to suffer corrosion, aging or other damage when heated in an inert atmosphere, so safety incidents such as leakage will not occur. Stainless steel, aluminum or ceramic fiber and other suitable materials may be selected as the material of the heat exchange panel and heated coil.

(14) The choice of material for each part of the heat exchange apparatus of the present invention (including component composition, thickness, strength and finish, etc.) depends on the nature of the fluid in contact therewith and conditions such as temperature and pressure during operation. For example, the heat exchange panel 6 needs to have excellent thermal conduction properties, and can tolerate rapid variation of temperature within a large range. A tube wall of the heat-receiving fluid coil 8 not only needs to have good thermal conduction properties, but also must not react with the heat-receiving fluid within the range of temperatures that might be reached during use. When the heat-receiving fluid is O.sub.2 or an oxygen-enriched gas (i.e. a mixed gas with an oxygen content higher than the content of O.sub.2 in air, optionally higher than 50%, and further higher than 80%), the material in contact therewith must not burn in a hot oxygen atmosphere, and is resistant to corrosion and oxidation.

(15) The heat exchange efficiency of the heat exchange apparatus and the temperature of the heat-receiving fluid outlet can be regulated in various ways. When the temperature and flow speed of the high-temperature fluid in the pipeline remain substantially the same, if the flow rate and flow speed of the auxiliary fluid are increased, the temperature of the auxiliary fluid after being heated will fall, and correspondingly the temperature of the heat-receiving fluid will also fall; if the auxiliary fluid is a gas, increasing the pressure thereof will cause the density thereof to increase, thereby increasing the heat transfer efficiency. Similarly, as long as other conditions remain unchanged, if the flow speed or flow rate of the heat-receiving fluid is increased, the outlet temperature thereof will also fall.

(16) In order to prevent leakage due to corrosion or aging of the heat-receiving fluid coil 8 under heated conditions, a gas component analyser 18 is provided at the auxiliary fluid outlet pipeline 5; if the determined gas components are not the same as the components of the auxiliary fluid and the heat-receiving fluid content is increased, this indicates that the heat-receiving fluid coil has suffered damage or leakage. In this case, it is advisable to immediately stop using the heat exchange apparatus, and carry out maintenance.

(17) In an embodiment, flue gas generated by combustion is passed into the transporting pipeline, the main components of the flue gas being carbon dioxide, water, carbon monoxide, sulfur dioxide and nitrogen oxides, etc., with a range of temperature variation of 500-1200? C.; the heat-receiving fluid is O.sub.2, and air is chosen as the auxiliary fluid. The flow rates, flow speeds and pressures, etc. of the heat-receiving fluid and auxiliary fluid are each controlled by controllers in their respective delivery systems. The range of variation of the flow rate of the heat-receiving fluid is 5-100 m/s, preferably 20-60 m/s; the range of variation of the flow rate of the auxiliary fluid is 0-50 m/s, preferably 20-30 m/s. It is expected that the range of variation of the temperature capable of being attained by O.sub.2 through heating is 300-600? C.

(18) The present invention is not limited to the illustrated examples and embodiments described; various equivalent modifications and substitutions made by those skilled in the art on the basis of this text shall be included in the scope defined by the claims of the present application.