GB2513633A

GB2513633A - Nozzle connection for carbon steel tank in special service

Info

Publication number: GB2513633A
Application number: GB201307952A
Authority: GB
Inventors: Philippe Heisch; Philippe Fauvel
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2013-05-02
Filing date: 2013-05-02
Publication date: 2014-11-05
Also published as: GB201307952D0

Abstract

A connection for use in a tank to join a first pipe 48 having a first passageway 70 with a second pipe 40 having a second passageway 68 comprises: a block member 56 having a conduit extending therethrough and being disposed between the first and second passageways such that the conduit is in communication therewith; and a seal assembly for sealing the block member in a fluid-tight connection with the first and second pipes. The first and second pipes may be formed from stainless steel, or carbon steel or austenitic steel clad internally with stainless steel. The seal assembly may comprise a tightening ring 60 and ring gasket 66 arranged exterior to the block member, along with first 64 and second 54 welds joining the first and second pipes to the block member respectively.

Description

NOZZLE CONNECTION FOR CARBON STEEL TANK

IN SPECIAL SERVICE

BACKGROUND

(0001] The present embodiments r&ate to nozzle connections for pipes used with and inside tanks or vessels.

[0002] Containment tanks or vessels are known and inchide nozzles or sockets extenthng into the vessels for introduction or release of fluids. For example, U.S. 5,404,382 to Russ et al. discloses a method of exchanging a nozzle passing through a cover of a nuclear reactor pressure vessel, wherein an inside of a sleeve for the nozzle with its stresses caused by the weld seam is no longer contacted by a medium located in the reactor pressure vessel. U,S.

6206228 to Roth discloses a doubl&wall tank for storing fluids, such as heating oil and the like, wherein a jacket space between an inside container consisting of plastic, and an outside container produced from sheet steel is encapsulated with liquid and is substantially ga&tight. Reliable protection against corrosion is assured, because of the penetration4ree connection technique inside and outside the containers, The doublewall tank of Roth is especially designed for storing petroleum oil products.

[0003] However, in for example carbon steel tanks, containers or vessels for use in special services, such as for example ammonia (NH3) service, mixed welds (carbon steel plus stainless steel) should or must be avoided. A welded connection is preferred to a flanged connection especially at an inside of the tank. The use of special alloys for the weld is very expensive and in certain instances, more labor intensive, especially for those alloy materials that are difficult to obtain on the market. The liquid product being discharged from the tank wifl and must conUnue to have high deanflness and purity. Therefore, aU piping. including connections, downstream of the vessel should be made of stainless steel to ensure product quaty and to decrease situations where contamination can occur (with for example carbon steel particles). Preferably, the complete ouflet piping induding any internal piping should be stainless steeL Due to special services as mentioned above, the stainless steel piping should not be welded to a carbon steel wall of the lank, especially not directly to pressure or bad bearing components. In addition, a flanged connection is not suitable in this case. Therefore, a special nozzle connection is needed which can be applied to either single wall or double wall tanks.

[0004] Containment vessels or tanks constructed from carbon steel for special service, such as for example NH3 service, with outlet piping extending throuah both sidewalls or shells of the tank should be made from a material similar to that oF the tank. The similarities of the materials of the tank walls and the piping do not result in any problems occurring where the piping extends through the tank sidewaUs, How:ver, it is not possible or cost effective to in all instances have piping and tank sidewalls constructed of similar or compatible materials.

[0005] The guaranteed lifetime of special service tanks or vessels, such as an NH3 vessel, is usually 2O3O years. But in such special service vessels, such will not be possible to connect or join carbon steel with austenitic steel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For a more complete understanding of the present embodiments, reference may be had to the following description taken in conjunction with the drawing Figures, of which: (0007] FIG. 1 shows a partial cross-section of a side view of a special service tank or vessel having a nozzle connection embodiment of the present invention; and [00081 FIGS. 2-5 show partial cross-sections of nozzle connection embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(00091 in general, the present embodiments of FIGS. 1-5 provide for apparatus and methods to promote the economic life of a special service tank or vessel by providing nozzle connection components which are compatible with each other and the vessel sidewalls and the fluid contained in the vessel.

(0010] In particular and referring to FIG. 1, there is disclosed a tank 10 or vessel to be used for example for special service such as with NH3. The tank 10 includes an outer shell 12 or sidewall extending to and joined with a roof 14 or crown. Another end of the sidewall 12 extends to and Is connected with a bottom 16 for the tank. The tank 10 also includes an inner shell or sidewall 18 for providing an interior chamber 19, in which a fluId 20 is contained therein. The fluid 20 may be for example ammonia (NH3). A space 21 or void is provided between the outershell 12 and the inner shell 18. Of note Is that the present embodiments can be used in single or double walled tanks.

(0011] The tank lois provided with an upper suspended deck for platfomi for supporting an insulation material 24 such as for example mineral wool. The kiner shell 18 is also provided with insulation 26 at an exterior of the inner shell.

A region of the outer shell 12 Is also provided with a thermal shock barrIer 28 of Insulation such as for example polystyrene. The thermal shock barrIer 28 is disposed at an interior surface of the outer shefi 12. The insulation material 24 is exposed to a headspace of the interior chamber 19 above a surface of the fluid 20. The insulaflon 2$ and the thermal shock baffler 28 are each exposed to the void 21.

[0012] Insulation 30 is provided beneath the bottom iS and rests upon a foundaflon 32 or base platform of the tank 10. The foundation 32 may be manufactured of cement and can be provided with heating pipes 34 or conduits extending therethrough to prevent freezing of the tank 10 and the fluid 20 therein, and at least to facilitate a uniform temperature of the fluid.

[0013] A pipe 36 or conduit is constructed to extend through the outer sheU 12 to uRimately be in communication with the fluid 20 within the tank 10. A nozzle connection 38 interconnects the pipe 36 with an internal pipe 40 or conduit which extends from the chamber 19 to he connected with the pipe 36. The internal pipe includes a valve 42. The pipe 36 includes an expansion bellows 44.

[0014] Referring to FIGS. 2 and 3, a first embodiment of a nozzle connection is shown generaHy at 46, wherein pipe 36 is constructed of carbon steel and is internaUy clad with a stainless steel lining or has a stainess steel pipe therein, and is connected by a leakproof weld 50 to a carbon steel pipe porilon 48 which is also internafly clad with a stainless steel lining or has a stainless steel pipe therein. Welds 52 are also provided to secure the pipe 48 as it passes through the inner sheU 18. The pipes 36,48 of carbon steel are welded to carbon steel of the inner sheU 18, so that there is no dissimUar weld. The stainless steel cladding or internal pipes may be used with all of the present embodiments.

[0015] The internal pipe 40 is connected by a weld 54 to a weld connection member 56 being externally threaded at 58. A tightening ring 60 is internally threaded at 62 for threaded engagement with the external threading 58 of the weld connection member 56, as shown more particularly in FiG. 3. Another weld 64 is disposed to join the weld connection member 56 to an interior surface of the inner shell 18. A ring gasket 66 is disposed between the inner surface of the inner shell 18 and a surface of the weld connection member 56 facing the inner shell.

(0016] As shown in FiG. 3, the internal pipe 40 is welded to the weld connection member 56, whIch In turn Is welded to the inner shell 18, such that an interior bore 68 or passageway of the internal pipe 40 wIll be in registration with an internal bore 70 or passageway of the austenitic steel pipe portion 48.

Refening also to FIG. 2, the internal bore 7Ois therefore in communication with an internal bore 72 or passageway of the pipe 36.

(0017) The ring gasket 66 provides an effective seal upon rotation of the tightening ring 60 toward the Inner surface of the inner shell 18. WIth such a construction as shown In FIGS. 2 and 3, there will be no contact with and incompatibility between the pipe 36, the austenitic steel pipe portion 48 and the internal pipe 40. There is therefore no carbon steel -austenitlo steel contact or connection which could corrode and compromise the integrity of the inner shell 18, the outer shell 12 or the tank 10.

[0018] Referring to P10.4, there is shown another embodiment of the nozzle connection generally at 55. The weld connection member 561s not threaded, but rather, is seated against an stress relief protection plate 74 which includes a buttering portion/alloy buttering 76 constructed as a ring as well. Leak-proof welds 78 are provided where the weld connection member 56 contacts the stress relief protection plate 74 as shown. Such construction as shown in FiG. 4 permits the connection of carbon steel with an austenitic steel.

S

[00191 FIG. 5 shows still another embodiment of the present Invention generally at 79. A weld connectIon member 80 is welded to and seated against the stress relief protection plate 74 as called in the embodiment of FIG. 4.

However, the weld connection member 80 of FIG. 5 includes an internally threaded portion shown generally at 82 for threadably engaging a threaded portion of an Internal pipe 84 or conduit from the interior chamber 19. Threads 86 at an exterior surface of the Internal pipe 84 are provided for threaded engagement of the internal pipe to the weld connection member 80.

[0020] The intemal pipe 84 is provided with its end having a seal 88 such as a ring gasket to contact an Interior wall of the weld connection member 80 as shown In FIG. 5.

[0021] The present embodiments provide for an economic of life of the service vessel to be 20-30 years and It is possible to connect carbon steel components with for example austenitic steel components. Parts for the nozzle and other components which will be disposed at the interior of the contaminant tanks can be manufactured from austenitic steels, instead of or expensive alloy materials.

The problems associated with temperature differences during start-up and operation of the vessel by using the austenltlc expansion bellows are substantially reduced If not eliminated by the present embodiments.

(0022] In addition, the service vessel and the present components provide for a relatively maintenance-free construction. It Is also possible to change components and parts of the nozzle connections 46, without welding between carbon steel and austenitic steel.

[0023] It will be understood that the embodiments described herein are merely exemplary, and that one skilled in the art may make variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope ot the Invention as described and claimed herein. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired result.

I

Claims

CLAIMSWhat is daftned is: A connecfion for joining a first pipe having a first passageway with a second pipe having a second passageway, comprising: a block member having a conduit extending therethrough and being disposed between the first and second passageways such that the conduit is in communication therewith: and a seal assembly for seang the block-member in a fluid-tight connection with the first and second pipes.
2. The connection of dairn 1, wherein the first pipe is constructed from austenitic steeL and the second pipe is constructed from carbon steel with the second passageway clad in stainless steeL
3. The connection of claim 2, wherein the first passageway is clad in stainless steeL
4. The connection of claim 1, wherein the first passageway comprises a first stainless sted pipe and the second passageway comprises a second stainless steel pipe.
5. The connection of claim 1, wherein the seal assembly comprises: a tightening ring threadably engageable to an exterior surface of the block member; a first w&d joining the first pipe to the block member for the first passageway to be in fluid communicatbn wfth the conduit; a ring gasket disposed at an exterior of the block member for coaction with the fightening ring; and a second weld joining the second pipe to the block member for the second passageway to be in fluid communicaflori with the conduit.
6. The connection of claim 1, wherein the seal assembly comprises: a plate member disposed at an exterior of the block member opposite the first pipe for coaction with the block member; a buttering aHoy disposed at a surface of the plate member for contact with at least a portion of the exterior of the block member; a first weld joining the first pipe to the block member for the first passageway to be in fluid communication with the conduit; and a second weld joining the second pipe to the block member for the second passageway to be in fluid communication with the conduit.

7, The connection of claim 6, wherein the block member further comprises a threaded surface area in the conduit threadably engaging the first pipe.8; The connection of claim 7, wherein the first pipe further comprises: a first pipe gasket at a first end of the first pipe to be seated within the conduit; and a second pipe gasket axially positioned around the first passageway.9. The connection of claim 1, wherein the block member and the seal assembly are disposed for use within a tank.10. The connection of claim 9, whereIn the tank comprises a sidewall formed from carbon steel.11. The connection of claim 10, wherein the first and second pipes are formed from carbon steel, and the first and second passageways are each clad in stainless steel.