Heat exchange device for cooling synthetic gas and method of assembly thereof

Abstract

The invention relates to a heat exchange device comprising a channel wall defining a flow channel with an inlet for receiving a gas flow. The device further comprises one or more heat exchange surfaces positioned inside the flow channel creating different parallel flow paths for the gas flow through the flow channel, at least one of the heat exchange surfaces embedding one or more flow paths for a fluid heat exchange medium. The one or more deflection elements are positioned inside the flow channel and are attached to the channel wall to deflect the gas flow away from the channel wall.

Claims

1. A heat exchange device for cooling synthetic gas, the heat exchange device comprising: a channel wall defining a flow channel with an inlet for receiving a gas flow, wherein the channel wall is a gastight membrane wall comprising a plurality of pipe lines forming one or more flow paths for a cooling medium; one or more heat exchange surfaces positioned inside the flow channel creating different parallel flow paths for the gas flow through the flow channel, at least one of the heat exchange surfaces embedding one or more flow paths for a fluid heat exchange medium; and one or more deflection elements positioned inside the flow channel and attached to the channel wall to deflect the gas flow away from the channel wall, wherein the one or more deflection elements are positioned upstream of the heat exchange surfaces; wherein the deflection elements comprise a baffle plate and an anchor element, the baffle plate being connected to the anchor element, the baffle plate being positioned inside the channel wall to deflect the gas flow away from the channel wall and the anchor element extending outwardly from the channel wall through an opening in the channel wall and being attached to the channel wall on the outside of the channel wall.

2. A heat exchange device according to claim 1, wherein the one or more heat exchange surfaces are coaxially nested heat exchange surfaces of a closed geometry.

3. Heat exchange device according claim 1, wherein the deflection elements comprise a deflection surface which is at an angle with respect to the channel wall.

4. Heat exchange device according to claim 1, wherein the individual deflection elements extend over an angle along the inner perimeter of the channel wall, the angle being in the range 1045.

5. Heat exchange device according to claim 1, wherein a gap is present between the baffle plate and the channel wall.

6. Method of assembling a heat exchange device, the method comprising: a) providing a channel wall defining a flow channel with an inlet for receiving a gas flow, wherein the channel wall is a gastight membrane wall, comprising a plurality of pipe lines forming one or more flow paths for a cooling medium; b) providing one or more heat exchange surfaces positioned inside the flow channel creating different parallel flow paths for the gas flow through the flow channel, at least one of the heat exchange surfaces embedding one or more flow paths for a fluid heat exchange medium; and c) installing one or more deflection elements inside the flow channel by attachment to the channel wall to deflect the gas flow away from the channel wall, wherein the one or more deflection elements are positioned upstream of the heat exchange surfaces; wherein the deflection elements comprise a baffle plate and an anchor element, the baffle plate being connected to the anchor element, the baffle plate being positioned inside the channel wall to deflect the gas flow away from the channel wall and the anchor element extending outwardly from the channel wall through an opening in the channel wall and being attached to the channel wall on the outside of the channel wall.

7. Method according to claim 6, wherein c) comprises c1) providing an opening in the channel wall c2) positioning the one or more deflection elements with the baffle plate inside the channel wall and the anchor element protruding through the opening in the channel wall towards the outside of the channel wall, c3) attaching the deflection element on the outside of the channel wall.

8. Method according to claim 6, wherein the method further comprises: determining the temperature of the fluid heat exchange medium exiting the heat exchange surfaces, adjusting the number, size, position and/or configuration of the deflection elements.

Description

SHORT DESCRIPTION OF THE DRAWINGS

(1) Embodiments will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

(2) FIG. 1 shows a schematical view of a plant for the production of synthetic gas,

(3) FIG. 2 shows a side view of a heat exchange device according to an embodiment,

(4) FIG. 3a shows a cross sectional top view of part of a membrane wall,

(5) FIG. 3b shows a cross sectional view of the heat exchange device,

(6) FIG. 4a shows a cross sectional view of part of the heat exchange device

(7) FIG. 4b shows a top view of part of the heat exchange device,

(8) FIG. 5a shows a deflection element,

(9) FIG. 5b shows part of a membrane wall comprising an opening, and

(10) FIG. 5c shows a cross-sectional side view of a deflection element and a membrane wall.

DETAILED DESCRIPTION

(11) FIG. 1 schematically shows in cross section a plant for the production of synthetic gas, wherein the plant comprises at least one gasification reactor 101 in which carbonaceous feedstock is partially oxidized producing synthetic gas. The gasification reactor 101 comprises an upwardly inclined discharge section 103 for the produced syngas opening into the top section of a heat exchange unit 104 where the produced syngas is cooled. Cooling or quenching means may be present in the inclined discharge section 103 as well.

(12) The heat exchange unit 104 comprises a closed cylindrical outer wall 2 forming a pressure vessel and encasing a heat exchange device 1. The heat exchange unit 104 further comprises a cylindrical inner channel wall 3, which extends through the heat exchange device 1 and is thus also part of the heat exchange device 1. The heat exchange device 1 is described in more detail with reference to FIG. 2.

(13) It will be understood that FIG. 1 is a schematic representation. Many details are not shown for reasons of clarity, such as burners, supply and discharge lines of oxygen, fuel, slag, cooling fluids, quench device, etc.

(14) FIG. 2 shows the heat exchange device 1 in more detail. The heat exchange device 1 comprises the cylindrical inner channel wall 3, having a central body axis R. The channel wall 3 is formed by parallel vertical cooling liquid conduits interconnected to form a gastight tubular membrane confining a (gas) flow channel 7. A cooling medium, such as water flows through the pipe lines of the channel wall 3.

(15) The discharge section 103 of the gasifier unit opens into an inlet of the flow channel 7. Syngas flows in the direction of arrows A (also see FIG. 1), upwardly from discharge section 103 of the gasifier unit into the heat exchange unit 104 through the flow channel 7 to a lower outlet area.

(16) The channel wall 3 encloses a set of five schematically represented nested coaxial heat exchange surfaces 5a, 5b, 5c, 5d and 5e. In practice, two or more may be usedfor example heat exchange surfaces 5a and 5b. Like the channel wall 3, the heat exchange surfaces 5a-5e are built of parallel tubular lines. Optionally, the tubular lines of the heat exchange surfaces 5a-e can be helically wound.

(17) The heat exchange surfaces 5a-5e embed one or more flow paths for a fluid heat exchange medium. The heat exchange device 1 therefore comprises one or more coolant supply lines 11 which split via one or more manifolds or distributors 12 into separate coolant supply lines 13 which are in fluid connection with the flow paths embedded in the heat exchange surfaces 5a-5e. The heat exchange device 1 further comprises separate coolant discharge lines 14 which combine via one or more manifolds or headers 15 into one or more combined coolant discharge lines 16. The arrangement of the supply lines and discharge lines can also be reversed.

(18) A support structure 20 is provided to support the heat exchange surfaces 5a-5e. The support structure may have any suitable form, such as explained in WO2011/003889. The support structure may comprise three, four or more arms extending from a central crossing which are attached to the channel wall 3.

(19) The support structure and the present of coolant lines make the area above the heat exchange surfaces 5a-5e difficult to reach for personnel and make it difficult to perform welding operations inside the channel wall 3.

(20) The lower ends of each heat exchange surface 5b-5e extend past the lower end of the adjacent outer heat exchange surface, respectively. This way, each individual heat exchange surface can be cleaned individually by using rapper devices (not shown).

(21) The channel wall 3 defines a flow channel 7 in which different parallel flow paths are created by the heat exchange surfaces 5a-5e towards a discharge. The flow path inside the most inner heat exchange surface 5e may be closed off by a closing member 17.

(22) FIG. 2 further shows deflection elements 40 positioned inside the flow channel 7 and attached to the channel wall 3 to deflect the gas flow away from the channel wall 3.

(23) FIG. 3a schematically shows a cross sectional top view (in the direction of the central body axis R) of part of the channel wall 3, formed by parallel vertical cooling liquid conduits 31 interconnected by fins 32 to form a gastight tubular membrane. In one of the fins an opening 33 is schematically indicated, as will be explained in more detail below.

(24) FIG. 3b schematically shows a cross sectional view (in a direction perpendicular to the central body axis R) of part of the heat exchange device 1, showing in more detail the presence of the channel wall 3 comprising conduits 31, the nested heat exchange surfaces 5a-5e positioned coaxial with respect to the central body axis R and deflection elements 40 positioned upstream of the heat exchange surfaces 5a-5e, leaving a gap d between the deflection elements and the heat exchange surfaces. Gap d is shown in more detail in FIG. 4a.

(25) FIG. 4a schematically shows a cross sectional view (in a direction perpendicular to the central body axis R) of a deflection element 40 with respect to the channel wall 3. By way of example FIG. 4a shows a conduit 31. The deflection element 40 comprises a deflection surface 41 which deflects the gas flow away from the channel wall 3, as schematically indicated by arrows A. The deflection surface 41 is at an angle with respect to the channel wall 3 or longitudinal axis R.

(26) FIG. 4b schematically shows a top view of part of the heat exchange device 1 showing the channel wall 3 comprising the parallel vertical cooling liquid conduits 31 interconnected by fins 32. Also shown is a deflection element 40 with a deflection surface 41. The deflection surface 41 has an outer edge 45 which matches the shape of the channel wall 3 such that a gas tight sealing is created. The deflection surface 41 further has an inner edge 46 which forms part of circular section which runs coaxial with respect to the channel wall 3. The deflection element 40 extends over an angle with respect to the central body axis R. The angle being in the range 1045, preferably in the range 1030.

(27) FIG. 5a shows a deflection element 40 comprising a baffle plate 43 and an anchor element 42.

(28) FIG. 5b shows part of the channel wall 3, showing two conduits 31 and a fin positioned in between. The fin 32 comprises an opening 33, having dimensions that allow the anchor element 42 to be positioned in the opening 33.

(29) FIG. 5c schematically depicts a cross sectional view of the channel wall 3 at the location of a conduit 31 showing deflection element, comprising baffle plate 43 and anchor element 42 extending through the channel wall 3. Further shown are a pad 47 and sealing plate 48. Pad 47 is welded to the channel wall 3 comprising an opening to allow the anchor element 42 to go through. The pad 47 has a shape which matches the outside of the channel wall 3. Sealing plate 48 is welded to pad 47. Sealing plate 48 comprises an opening to allow the anchor element 42 to go through.

(30) FIG. 5c schematically shows a gap d2 between the channel wall 3 and outer edge 45 of the deflection element 40 or deflection surface 41. This gap d2, measured in a radial direction perpendicular to the central body axis R is present to overcome difference in thermal expansion between the deflection element 40 or deflection surface 41 and the channel wall 3 and is preferably kept as small as possible to minimize the gas flow through this gap d2. Gap d2 is preferably smaller than 2 mm.

(31) Next, a method of assembly is described in more detail. The method comprises a) providing a channel wall 3 defining a flow channel with an inlet for receiving a gas flow, b) providing one or more heat exchange surfaces 5a-d positioned inside the flow channel 3 creating different parallel flow paths for the gas flow through the flow channel, at least one of the heat exchange surfaces 5a-d embedding one or more flow paths for a fluid heat exchange medium; and c) installing one or more deflection elements inside the flow channel by attachment to the channel wall to deflect the gas flow away from the channel wall 3.

(32) Action c) comprises inserting the deflection elements 40 from the top of the heat exchange device 1 and slide the anchor element 42 through the opening 33 created in the channel wall. Before or after this, pad 47 is welded to the channel wall 3, such that after inserting the deflection element the anchor element also extends through an opening in the pad 47. Next, sealing plate 48 is welded pad 47 and anchor element 42 is welded against the sealing plate 48 to create a gastight seal.

(33) The deflection elements may be fitted all along the circumference of the channel wall 3 or only along part of the circumference.

(34) As shown in FIGS. 5a-5c, the opening 33 is such that there is a tightfit between the opening 31 and the anchor element 42. This is to make positioning of the deflection element 40 relatively easy as only the radial position can be varied. However, this allows for limited positioning freedom when positioning a deflection element.

(35) According to an alternative embodiment, the opening 33 is wider and taller than the anchor element 42. The fin 32 may be even cut away completely between adjacent tubes 31 over a predetermined height to create clearance between anchor element 42 and the edges of the opening 33 in the circumferential and vertical/axial direction. Also the dimensions of the opening in the pad 47 are chosen the same as the dimensions of opening 33 or at least larger than the dimensions of the anchor element 42. The dimensions of the opening in the sealing plate 48 are chosen such that a tight fit is created between this opening and the anchor element 42. For instance, the dimensions of the opening in the sealing plate 48 are chosen in the range of 1-2 mm larger than the dimensions of the anchor element 42. This embodiment has the advantage that the deflection element 40 can be aligned in all directions (radial direction, circumferential direction and height direction (parallel to longitudinal axis R)) with respect to the channel wall before it is connected.

(36) Alternatively, instead of pad 47 and sealing plate 48, only one sealing plate is provided, which has an opening chosen such that a tight fit is created between this opening and the anchor element 42.

(37) Descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.