High Speed Liner

TECHNICAL FIELD

The present invention generally relates to an internal lining system for use in an industrial chimney, and more particularly relates to a design on the construction elements of the internal lining system for operations with wet stack conditions.

BACKGROUND

A wet stack operation happens when flue gas passes on into an exhaust pipe or chimney stack, such as in coal-fired power plants employing wet flue gas technologies. When saturated flue gases enter the chimney stack, sometimes in combination with droplet carryover from the absorber mist eliminators and condensation, the surfaces of chimney stack liner are covered with liquid which must be collected and drained from the system. If the chimney stack liner is not properly designed, liquid in the form of droplets may be entrained in the flue gas flow and ejected from the top of the chimney stack, resulting in a phenomenon called Stack Liquid Discharge (SLD).

The Revised Wet Stack Design Guide, final report 1026742, Copyright © 2012 Electric Power Research Institute, Inc., (“EPRI Guide”) provides a guide on wet stack design. From the EPRI Guide it is known that one of the important issues to consider in the design of a wet stack system is the gas velocity in the chimney. This is because when the gas passes through a chimney, liquid films are produced by droplet deposition and condensation on the liner surface and flows in the form of liquid sheets and rivulets. As the liquid accumulates, the resulting liquid film is directed downward by gravity. At the same time, gas-shear forces push the liquid in the same direction as the flow of the gas. When the gas-shear force reaches or exceeds the forces of gravity, the downward flow of liquid slows and the film thickness increases. The thicker liquid film becomes unstable and re-entrains droplets back into the gas stream and are carried out of the chimney stack. Re-entrainment is the most frequent source of SLD and should be avoided. When re-entrainment occurs, the gas velocity is referred to as the critical re-entrainment velocity.

Different materials and construction techniques for the internal liner affect the critical re-entrainment velocity. For example, surface discontinuities and protrusions, such as weld seams, fiberglass-reinforced plastic (FRP) joints, and joints of mortar or mastic in the internal liner may disrupt gas and liquid flow locally, causing re-entrainment in the form of large droplets (300-6000 microns).

Table 2-1 of the EPRI Guide provides recommendations of the maximum stack gas velocities for several lining materials. To reduce the cost of the chimney and avoid SLD, it is common to operate at the maximum recommended gas velocity to remain below the critical droplet re-entrainment velocity. The recommended values provide some margin to account for increases in the flue gas flow rate as a result of changes in fuel source, increases in plant efficiency, and/or future increases in plant output. For example, for borosilicate blocks, the recommended stack-liner velocity for wet operation is 18.3 m/s (60 ft/s), and this recommendation considers the significant increase in the effective surface area afforded by the closed-cell surface structure of the material and the resulting increased surface-tension forces holding the liquid to the material.

As such, there is a need to address the above problems in the art.

SUMMARY

The needs set forth herein as well as further and other needs and advantages are addressed by the present teachings, which illustrate solutions and advantages described below.

It is an object of the present teachings to provide an internal lining system for an industrial chimney to raise the critical re-entrainment velocity of the flue gas.

It is another object of the present teachings to provide an internal lining system for an industrial chimney to be operated at a gas velocity higher than the currently recommended value.

According to one aspect of the present teachings, an internal lining system for a chimney is provided, which comprises a first building block and a second building block, each having a front face facing gas flowing through the industrial chimney; a joint of binding material configured to connect the first and second building blocks such that the front faces of the first and second building blocks are aligned; and a slot formed on the front face of the first building block, crossing the joint of binding material, and formed on the front face of the second building block; wherein the slot has a depth smaller than depths of the first and second building blocks.

In some embodiments, the joint of binding material comprises a horizontal joint of binding material. In some embodiments, the slot comprises a straight line when viewed from a front-face side of building blocks. In some embodiments, the slot is formed at a 90-degree angle with respect to a horizontal line. In some embodiments, the slot is formed at a 45-degree angle with respect to a horizontal line. In some embodiments, the slot comprises two straight lines across each other when viewed from a front-face side of building blocks. In some embodiments, the slot is formed in a shape of X having the two straight lines meet at the joint of binding material. In some embodiments, the depth of the slot is not uniform. In some embodiments, the slot is formed by using a grinder, biscuit joiner, or similar tool. In some embodiments, the first and second building blocks are made of borosilicate glass. In some embodiments, the first and second building blocks are made of brick. In some embodiments, the internal lining system is attached to an inner surface of the industrial chimney to protect a wall of the industrial chimney.

According to another aspect of the present teachings, a chimney with an internal lining system is provided. The chimney is an industrial chimney for wet stack operation.

According to yet another aspect of the present teachings, a process of using the internal lining system for a purpose of increasing a critical re-entrainment velocity is provided.

Other teachings of the system and method are described in detail below and are also part of the present teachings.

For a better understanding of the present teachings, together with other and further aspects thereof, reference is made to the accompanying drawings and detailed description, and its scope will be pointed out in the appended claims. The summary is not intended to limit the scope of the present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view illustrating a part of the internal lining system according to the present teachings;

FIG. 2 is a front view illustrating slots formed on the flue gas side of the internal lining system according to the present teachings;

FIG. 2A is a magnified view of the marked portion of FIG. 2;

FIG. 3 is a front view illustrating slots formed on the flue gas side of the internal lining system according to the present teachings;

FIG. 3A is a magnified view of the marked portion of FIG. 3;

FIGS. 4A-4C and 5A-5C illustrate examples of slots formed on different arrangements of blocks and joints in the internal lining system according to the present teachings; and

FIG. 6 is a schematic view of an industrial chimney including the internal lining system according to the present teachings.

DETAILED DESCRIPTION

The present teachings are described more fully hereinafter with reference to the accompanying drawings. The following description is presented for illustrative purposes only and the present teachings should not be limited to these embodiments.

In compliance with the statute, the present teachings have been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the present teachings are not limited to the specific features shown and described, since the devices and methods herein disclosed comprise preferred forms of putting the present teachings into effect.

For purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding. In other instances, detailed descriptions of well-known devices and methods are omitted so as not to obscure the description with unnecessary detail.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. The use of “first”, “second,” etc. for different features/components of the present disclosure are only intended to distinguish the features/components from other similar features/components and not to impart any order or hierarchy to the features/components.

The present teachings provide an internal lining system for an industrial chimney. The internal lining system includes building blocks or construction elements, joints of binding material (e.g., mortar or mastic) connecting the building blocks or construction elements, and at least one slot formed on the front faces (i.e., flue gas sides) of the building blocks or construction elements that crosses the joints of binding material to increase the critical re-entrainment velocity of the flue gas in the chimney and/or to have the chimney operated at a gas velocity higher than the currently recommended value. Preferably, the slots are formed across the joint at least partially in the direction of flow and more preferably in the direction of flow (i.e., vertically).

In some embodiments, the slot comprises a straight line when viewed from a front-face side of building blocks or construction elements. In some embodiments, the slot comprises two straight lines across each other when viewed from a front-face side of building blocks or construction elements, such as a shape of X. The two straight lines may cross each other at the joint. In other embodiments, the slot comprises additional straight line(s) when viewed from a front-face side of building blocks or construction elements. Although the slot is described as having straight line(s), it should be understood by person with ordinary skill in the art that other shapes, such as curve(s), arc(s), or a combination thereof (including straight line), are suitable for the present teachings.

In some embodiments, the material of the building blocks or construction elements is borosilicate glass, or more specifically, closed cell foamed borosilicate glass, or brick, or more specifically, acid-resistant brick, but other materials known in the art are also applicable. In some embodiments, the building blocks or construction elements are in a shape of a rectangle, but other shapes known in the art are also applicable.

FIG. 1 is a side view illustrating a part of the internal lining system 10 according to the present teachings. The internal lining system 10 is applied to an upstanding wall 11 of an industrial chimney. The wall 11 may be steel, concrete, ceramic brick, or any other material. In some embodiments, the inner surface of the wall 11 is first treated with a primer.

The internal lining system 10 includes blocks 12 and joints 14. The blocks 12 are applied with their back face to the inner surface of the wall 11 using a binding material. The front faces of the blocks 12 come into contact with the flue gas flowing through the chimney. The blocks 12 may have a shape of square, rectangle, rhombus, parallelogram, round, or any applicable shape known in the art. In some embodiments including the illustration in FIG. 1, the blocks 12 are made of closed cell borosilicate blocks, but any materials known in the art are applicable.

The adjacent blocks 12 are connected to each other by a binding material, forming joints 14. In some embodiments including the illustration in FIG. 1, the joints 14 include horizontal joints. In some embodiments, the joints 14 include vertical joints. Although illustrated throughout the specification that the joints are in a shape of straight lines (see FIGS. 2-7C), it should be noted that the joints may be in any shape, such as curve, and may be with a larger width or with any depth, as long as the joints connects the adjacent blocks 12, and may be in any type or arrangement or orientation.

In the internal lining system 10, a slot 16 is formed on the front faces of the adjacent blocks 12 and crossing the joints 14 between the adjacent blocks 12 from one block to another. In some embodiments, the slot 16 includes a straight line when viewed from the front faces of the adjacent blocks 12. In some embodiments, the slot 16 includes two straight lines crossing at the joints 14 when viewed from the front faces of the adjacent blocks 12. The depth of the slot 16 is smaller than the depth of the blocks 12 and the depth of the joints 14. In some embodiments, the depth of the slot 16 is uniform, such as illustrated in FIG. 1. In some embodiments, the depth of the slot 16 is gradually changed, such as using a grinder cut in the face (i.e., flue gas side) of the internal lining system 10. The slot 16 creates groove(s) in the face (i.e., flue gas side) of the internal lining system 10 that comes into contact with the flue gas flowing through the chimney.

FIGS. 2, 2A, 3 and 3A are front views illustrating slots 16 formed on the front faces of the blocks 12. FIG. 2A is an enlarged view of the marked portion in FIG. 2, and FIG. 3A is an enlarged view of the marked portion in FIG. 3.

Referring to FIGS. 2 and 2A, a vertical slot 16a is formed on the adjacent blocks 12 and across a horizontal joint 14 that connects adjacent blocks 12, and an angled slot 16b is formed on the adjacent blocks 12 and across a horizontal joint 14 that connects adjacent blocks 12. The vertical slot 16a is a vertical-straight slot having a length or height (marked), e.g., 2 inches, a width, e.g., 0.25 inch, and a depth (not shown), e.g., 0.125 inch. The angled slot 16b has the same dimensions as the slot 16a and forms an angle, e.g., 45 degrees, with respect to the horizontal.

Referring to FIGS. 3 and 3A, two angled slots 16b are formed on the adjacent blocks 12 and across horizontal joints 14 that connect adjacent blocks 12, and two X-shape slots 16c are formed on the adjacent blocks 12 and across horizontal joints 14 that connect adjacent blocks 12, The angled slots 16b form an angle, e.g., 45 degrees, with respect to the horizontal. The X-shape slots 16c are slots with a shape of “X,” e.g., each arm of X forming a 45-degree angle with respect to the horizontal line.

FIGS. 4A-4C and 5A-5C illustrate examples of slots formed on different arrangements of blocks and joints in the internal lining system. It is noted that the arrangements of blocks and joints in FIGS. 4A-4C and 5A-5C are shown only for the purpose to illustrate the slots. The slots can apply to any arrangements of blocks and joints.

FIG. 4A shows a part of the internal lining system having an arrangement of rectangular blocks with aligned horizontal joints and aligned vertical joints. FIG. 4B shows a part of the internal lining system having an arrangement of rectangular blocks with aligned horizontal joints and staggered vertical joints. FIG. 4C shows a part of the internal lining system having an arrangement of rectangular blocks with staggered horizontal joints and aligned vertical joints. In each FIGS. 4A-4C, a vertical slot, a right-angled slot, a left-angled slot, and a X-shape slot are formed on the front faces of the adjacent blocks and across the joint that connects the adjacent blocks.

FIGS. 5A-5C have similar illustrations to FIGS. 4A-4C except the blocks are in a parallelogram instead of rectangle. Specifically, FIG. 5A shows a part of the internal lining system having an arrangement of parallelogrammical blocks with aligned horizontal joints and aligned vertical-inclined joints. FIG. 5B shows a part of the internal lining system having an arrangement of parallelogrammical blocks with aligned horizontal joints and staggered vertical-inclined joints. FIG. 5C shows a part of the internal lining system having an arrangement of parallelogrammical blocks with staggered horizontal joints and aligned vertical-inclined joints. In each FIGS. 5A-5C, a vertical slot, a right-angled slot, a left-angled slot, and a X-shape slot are formed on the front faces of the adjacent blocks and across the joint that connects the adjacent blocks. Herein, vertical-inclined joints refer to joints forming an angle β in a range of 0<β 45 degree with respect to the vertical.

FIG. 6 illustrates an example of a chimney 100 which operates in wet stack conditions and includes a wall 11 and an internal lining system 10 according to the present teachings. The wall 11 delimits an upstanding duct for flue gas. An inlet 81 for introducing flue gas derived from an industrial plant 82, such as a (coal-fired) power plant provided with a wet desulphurization system 83, is positioned at a lower part of the chimney. A false floor 84 is positioned in the bottom of the chimney. A rear deflection plate 85 is positioned at the inner surface of the wall 11 opposite to the inlet 81 and has a horizontal part to provide support to the lower portion of building elements of the internal lining system 10 to rest on.

The present invention may be applied in industrial chimneys for wet stack operation during installation, repair, or retrofitting. The chimney provided with an internal lining system of the present invention can be operated at a gas velocity higher than the currently recommended value discussed above.

The effectiveness of the internal lining system according to the present teachings can be carried out through experiments. Below are inventive examples, comparing in contrast with comparative examples, for an experiment using visual observations.

The experiment setup is described as below. For comparative examples, a test panel representing a conventional internal lining system was constructed using conventional borosilicate glass blocks of nominally 38 mm thick, 152 mm wide, and 229 mm long, and using mastic as joints of binding material for connecting the borosilicate blocks. The borosilicate blocks were arranged in a staggered pattern such that the short edges (i.e., width) of the blocks were installed horizontally and the long edges (i.e., length) were installed vertically. In this experiment, the horizontal seams were aligned, and the vertical seams were staggered. The binding material in the joints was scraped during installation such that the binding material recessed slightly away from the front faces of the blocks. This test panel was constructed with a radial tolerance of less than 3 mm.

For inventive examples, a test panel representing an internal lining system according to the present teachings was constructed using the novel designed borosilicate blocks having same material and same dimensions as the conventional borosilicate blocks of nominally 38 mm thick, 152 mm wide, and 229 mm long, and using mastic as joints of binding material for connecting the novel designed borosilicate blocks in a way same as that in the comparative examples. The novel designed borosilicate blocks were arranged in a way same as that used in the comparative examples. The binding material in the joints was scraped during installation such that the binding material recessed slightly away from the front faces of the blocks. The novel designed borosilicate blocks include vertical slots, angled slots, and/or X-shape slots, formed on the front faces of the blocks and crossing the joints of binding material.

The test panels as manufactured were observed to have minimal adhesive smearing and minimal radial protrusions. Each panel was oriented vertically to mimic the orientation of a chimney. Each panel was then placed in a vertical wind tunnel test facility where several gas flow conditions ranging from 60 ft/s to 80 ft/s in increments of 5 ft/s can be applied to determine the performance of the panel with respect to liquid flow, drainage, and re-entrainment from the surfaces of the panel. Each panel was pretreated with water on the front faces of the blocks to simulate wet stack operation, as the internal liner surface is always wet due to condensation of water vapor from the saturated flue gas. Specific areas of interest were observed at different gas flow velocities to evaluate liquid drainage and entrainment of liquid from the borosilicate block surfaces or from joints between blocks.

The observations showed that the gas flow velocity in the internal lining system according to the present teachings can reach higher than that in the conventional lining system, resulting in a higher critical re-entrainment velocity.

While the present teachings have been described above in terms of specific embodiments, it is to be understood that they are not limited to these disclosed embodiments. Many modifications and other embodiments will come to mind to those skilled in the art to which this pertains, and which are intended to be and are covered by both this disclosure and the appended claims. It is intended that the scope of the present teachings should be determined by proper interpretation and construction of the appended claims and their legal equivalents, as understood by those of skill in the art relying upon the disclosure in this specification and the attached drawings.

High Speed Liner

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