GB2256261A

GB2256261A - Flow sampler safety interlock device

Info

Publication number: GB2256261A
Application number: GB9211517A
Authority: GB
Inventors: Peter A Hunzinger; Marcel J Krause
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1991-05-31
Filing date: 1992-06-01
Publication date: 1992-12-02
Anticipated expiration: 2012-06-01
Also published as: GB9211517D0; KR920021980A; GB2256261B; AU1701392A; CA2046103C; JPH05264419A; CA2046103A1

Abstract

A flow sampler device which can be employed in a catalytic reactor system comprises a sample receiver, and an inlet valve and an outlet valve which are each in fluid communication with the receiver. Each of the valves includes a valve stem 21 which is rotatable about a longitudinal axis thereof in a valve body so as to actuate the respective valve and has a collar element secured thereto. This collar element comprises a wall which defines a longitudinal passageway therethrough and a locking slot having a first portion 20 extending from a first end of the element and a second portion 22 which is substantially perpendicular to the first portion. In a preferred embodiment, the collar element is cylindrical and the locking slot is substantially L-shaped. The collar element effectively prevents a wrench which operates the valve from being removed from the valve stem when the valve is in an open portion. Thus, because only one valve is open at any time, the reactor is not allowed to vent through the sampling device. <IMAGE>

Description

SAMPLER SAFETY INTERLOCK DEVICE This invention relates to a flow sampler device, and in particular, a flow sampler which can be employed in a catalytic reactor system.

A variety of hydrocarbon conversion processes, for example, reforming, hydrocracking, hydrogenation, hydrodesulphurization and the like, utilise catalysts within a closed reactor vessel system, e.g. a fixed bed reactor vessel operated under super atmospheric pressure and elevated temperatures.

In such environments, catalysts are subject to poisoning by metallic contaminants, carbonaceous materials, and other components of the feed to the reactor vessel, such as sulphur and nitrogen.

Accumulation of these materials on the catalyst particles reduces the catalytic activity and, in severe cases, can cause plugging of the catalyst bed.

Accordingly, the art has sought ways of determining both the level and the nature of catalyst contamination so that th & regeneration of the catalyst can be carried out effectively and the timing of ultimate shutdown and replacement of the catalyst can also be forecast.

In particular, the art has sought means for obtaining catalyst samples in which the reactor itself is maintained on stream. Such sampling means must be effective in obtaining a sample which may be as high as, for example, 1000 F (538C) as well as several thousand pounds of pressure. Moreover, the catalyst sample needs to be obtained inexpensively without the risk of fire and/or injury to personnel.

A number of devices for withdrawing samples of catalysts are recognised in that art. One example, as described in US-A-3653265, employs the differential pressure between the reaction vessel and the solid receive to carry a catalyst sample from a bed of solids in the vessel to a tubular sampler and into the receiver where the sample is purged and cooled.

Another example, disclose in US-A-3654143, employs a suction nozzle to suck catalysts and reaction liquid from the reaction vessel.

US-A-3792612 relates to a catalyst sample in which a "safety interlock means" prevents both the inlet valve and the outlet valves of the sample from being open at the same time. In this system, a linkage, or lock bar, connects the inlet and the outlet valves thus causing both valves to turn simultaneously when either of them is turned. Accordingly, by opening one of the inlet or outlet valves the other is automatically closed.

Despite the ability of such an arrangement to prevent both of the valves from being opened at the same time, such a mechanical interlock arrangement is beset by a variety of problems. For example it is complicated to operate, it tends to stick, and is prone to wear with use. In addition, it is possible to override the interlock arrangement which clearly defeats its purpose.

The art has also employed a lock and key arrangement in which both the inlet and the outlet valves are secured by a keyed lock for which only one key is available. Accordingly, in order to open a valve, a key must be inserted into the lock. When the valve is opened, the key cannot be removed, ensuring that only one valve can be opened at any one time.

However, such an arrangement involves the use of keys which are easily (and often) lost, as well as locks which, particularly in this environment, become clogged with, e.g., dirt and thus rendered unusable.

Accordingly, the need still exists for a flow sampler which can overcome those problems associated with prior art devices. The present invention provides a flow sampler device which can effectively overcome those problems described above.

According to one aspect of the present invention, there is provide a flow sampler comprising: a sample receiver; an inlet valve and an outlet valve which are each in fluid communication with the sample receiver and which each includes a valve stem rotatable about its longitudinal axis in a valve body to actuate the respective valve; and respective collar elements, each having a first end and a second end, the second end of each collar being secured to a respective body; wherein each collar element comprises a wall means defining a longitudinal passageway through the element from the first end to the second end, said wall means including a locking slot defined therein, said locking slot including a first portion extending from the first end of the element and a second portion which is substantially perpendicular to the first portion.

According to another aspect of the present invention, there is provided a collar element for use with a valve, said collar element having a first end and a second end and comprising a wall means defining a longitudinal passageway through the element from the first end to the second end, said wall means having a locking slot defined therein; said locking slot including a first portion extending from the first end of the element and a second locking portion which is substantially perpendicular to the first portion; and means for securing the collar element to a valve body of the valve; whereby a wrench which has been inserted through the first portion of the slot can rotate the valve stem and further wherein the wrench so employed cannot be removed from the slot after the respective valve has been opened, without closing the respective valve.

In order to facilitate an understanding of this invention, reference will now be made to the appended drawings related to certain aspect of the present invention. The drawings are exemplary only, and should not be construed as limiting the invention.

Figure 1 illustrates the flow sampler arrangement according to the present invention; Figures 2 and 3 illustrate two embodiments of the collar element employed in the present invention; Figure 4 illustrates an adapter which can be employed in connection with a Rockwell ball valve; Figures 5 and 6 illustrate, in plan, an inlet or outlet valve employed in the present invention being actuated by a wrench; Figure 7 is a perspective view showing the valve in use in an open position; and Figure 8 is a side view of the valve and associated wrench shown in Figure 7.

The present invention relates to a flow sampler which can be employed, for example, to remove catalysts from a reaction vessel.

With reference to the preferred embodiment illustrated by Figure 1, a catalytic vessel 1 is in communication with a sample receiver 2 by way of an inlet valve 3. An outlet valve 4 is connected to the opposite end of the sample receiver 2.

The sampler receiver of the present invention include those, e.g., stainless steel storage vessels which are recognised in the art and thus need not be described in detail here.

Moreover, the valves which can be employed in the present invention include any of those valves which operate by way of a valve stem rotating in a valve body and which can be fully opened or closed by rotation of less than 360 , e.g., a 90" rotation thereof.

In one preferred environment involving the withdrawal of catalyst from a closed reactor vessel, plug valves such as those plug valves manufactured by Serck Audco and Rockwell are preferably employed.

A collar element is attached to the valve body of each valve in order to prevent a wrench which operates the valve from being removed from the valve step when the valve is in an open position.

This collar element comprises a wall means having a longitudinal passageway defined therethrough from a first end to a second end and further has a locking slot defined therein.

This locking slot has a shape which allows the wrench to engage the valve stem and, thus open the valve but which also prevents the wrench from being removed without closing the valve. Preferably, the locking slot comprises a first portion which extends from the first end of the collar and a second portion which is substantially perpendicular to the first portion.

In a preferred embodiment, the collar element is cylindrical with the locking slot being substantially "L-shaped". Specific examples of these preferred collar elements are illustrated in Figures 2 and 3 where the collar of Figure 2 is preferably employed with plug valves such as those produced by Serck Audco while that of Figure 3 is preferably employed with Rockwell plug valves.

The collar element can be attached to the valve body of the valve by any means recognised in the art, for example, as illustrated in Figures 2 and 3 by a plurality of set screws. In addition, when employed with certain valves, e.g., a Rockwell plug valve, an adaptor element such as that illustrated in Figure 4 can be employed in order to connect the collar element with the valve stem.

Figures 5 to 8 illustrate the operation of the valve. The wrench 8 is introduced into a first portion 20 of the locking slot of the collar to engage the valve stem 21. The wrench 8 is turned to open the valve and it moves into the second portion 22 of the slot in the collar and can no longer be removed from the valve stem (Figures 6 to 8).

The material of construction for the collar element is dependent upon the particular environment in which it is employed. For example, in the catalyst system of the preferred embodiment, the collar element can be made of stainless steel.

In operation, the catalyst sample may be obtained as follows. During normal reactor operation, both the inlet and the outlet valve remain closed. When a sample is desired, a valve in line 5 is opened to pressurise the sample receiver 2 to a pressure at least as high as the pressure in the reactor 1, and preferably about 25 to 50 pounds above the reactor outlet pressure at 7. After sampler receiver 2 is pressurised, the valve in line 5 is closed, and inlet valve 3 is then opened by wrench 8.

When the valve is to be opened, the wrench is slid into the first portion of the locking slot to engage the valve stem. When the wrench is turned to open the valve, it moves into the second portion of the slot in the collar and can no longer be removed from the valve stem.

On opening the inlet valve 3, catalyst material together with reactants enter sample receiver 2. The initial pressure in sample 2 is preferably at least the size of reactor outlet pressure, or higher to prevent catalysts from being prematurely drawn into the sampler.

The inlet valve 3 is then closed and catalyst sample is allowed to cool. A valve in line 6 is then opened to depressurise sample receiver 2 and remove reactants therefrom. The valve in line 6 is then closed and outlet valve 4 is opened by use of wrench 8.

Because only one valve can be opened at any one time, the reactor is never allowed to vent through the sampling device.

As noted, the catalyst drawn into sampler receiver 2 should be allowed to cool before opening outlet valve 4. The cooling of the catalyst sample can be expedited by, for example alternatively pressurising the sample receiver 2 by sequentially (1) opening the valve in line 5 with all the other valves in the closed position, (2) closing the valve in line 5 and (3) opening the vent relief valve in line 6.

In the present invention, a single wrench is employed so that when it is "locked" onto one of the valves, the other valve cannot be opened. Moreover, because a single wrench operates both valves, it can be attached to the system in such a way as to prevent it from becoming easily lost. For example, as illustrated in Figure 1, it can be connected to a support bracket attached to the sampler 2. The wrenches that can be employed in opening and closing the valves in the present invention are any of those known in the art and are chosen depending on the particular valve.

Although this sampler is preferably employed, e.g., a reforming reactor environment, it can be employed in any sampling operation involved in collecting solids, liquids, or gases from processing equipment where exposure to the process media to the atmosphere would be detrimental, including high temperature processes, high pressure processes, with processes involving materials which are air or water sensitive.

Moreover, various modifications or changes in arrangements shown in the preferred embodiment can be made without departing from the scope of the invention.

For example, the sampler can be employed without pressurising the vent lines, particularly when low pressures are utilised within the reactor.

Claims

1. A flow sampler comprising: a sample receiver; an inlet valve and an outlet valve which are each in fluid communication with the sample receiver and which each includes a valve stem rotatable about its longitudinal axis in a valve body to actuate the respective valve; and respective collar elements, each having a first end and a second end the second end of each collar being secured to a respective body; wherein each collar element comprises a wall means defining a longitudinal passageway through the element from the first end to the second end, said wall means including a locking slot defined therein, said locking slot including a first portion extending from the first end of the element and a second portion which is substantially perpendicular to the first portion.

2. A sampler according to claim 1, wherein the locking slot in each collar element is located relative to the end of the valve body to which it is secured such that a wrench which has been inserted through the first portion of the slot can rotate the valve stem and further wherein the wrench so employed cannot be removed from the slot after the respective valve has been opened without closing the respective valve.

3. A sampler according to claim 1 or 2, wherein the locking slot of the collar is substantially Lshaped.

4. A sampler according to claim 1, 2 or 3, wherein the wall means defines a substantially cylindrical passageway.

5. A sampler according to any preceding claim, wherein the element is secured to the valve body by way of at least one hole defined in the wall means near the second end of the element.

6. A sampler according to any preceding claim, wherein the sample receiver is a particulate solids storage vessel, the inlet valve is a particulate solids inlet valve, and the outlet valve is a particulate solids outlet valve.

7. A sampler according to claim 6, further comprising means to pressurise and depressurise the solids storage vessel.

8. A sampler according to claim 6 or 7, wherein each of the valves is a plug valve.

9. A sampler according to any preceding claim wherein both the inlet valve and the outlet valve are secured to the receiver.

10. A sampler according to any preceding claim, further comprising an adaptor which is connected between the valve stem and the collar element.

11. A sampler according to any preceding claim, further comprising means for attaching a wrench to the receiver which wrench is capable of actuating each of the valves.

12. A collar element for use with a valve, said collar element having a first end and a second end and comprising a wall means defining a longitudinal passageway through the element from the first end to the second end, said wall means having a locking slot defined therein; said locking slot including a first portion extending from the first end of the element and a second locking portion which is substantially perpendicular to the first portion; and means for securing the collar element to a valve body of the valve; whereby a wrench which has been inserted through the first portion of the slot can rotate the valve stem and further wherein the wrench so employed cannot be removed from the slot after the respective valve has been opened, without closing the respective valve.

13. A collar element according to claim 12, wherein the locking slot is substantially L-shaped.

14. A collar element according to claim 12 or 13, wherein the wall means defines a substantially cylindrical passageway.

15. A collar element according to claim 12, 13 or 14, wherein the wall means further has at least one hole defined therein near the second end of the element.

16. A flow sampler substantially as hereinbefore described, with reference to the accompanying drawings.