GB1565133A - Apparatus for burning hydrogen sulphide and organic sulphur compounds into a product suitable for recovery of free sulphur therefrom - Google Patents

Description

(54) APPARATUS FOR BURNING HYDROGEN SULFIDE AND ORGANIC SULFUR COMPOUNDS INTO A PRODUCT SUITABLE FOR RECOVERY OF FREE SULFUR THEREFROM (71) We, JOHN ZINK COMPANY. of 4401 South Peoria. Tulsa. Oklahoma. United States of America; a corporation organized and existing under the laws of the State of Delaware. United States of America do herebv declare the invention. for which we Pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an apparatus for burning hydrogen sulfide and organic sulfur compounds into a product suitable for the recovery of free sulfur therefrom.

In the prior art, sour gas streams. that is.

hydrogen sulfide streams have been processed bv the well known Claus process which initially burn approximatelv 1!3 of the hydrogen sulfide. then is further processed to obtain free sulfur.

This invention relates to reactions for the conversion of hydrogen sulfide where larger amounts of any organic sulfur compounds which may be contaminated with ammonia and/or hydrocarbons. either liquid or gaseous, are present. Conventional Claus reaction processes are limited to gaseous hydrogen sulfide and air with only trace amounts of gaseous hydrocarbons.

There are manv refineries or process areas having fixed streams of H2S and for example NH3 mixed with H2S. The NHI. if introduced into the usual Claus reaction and sulfur recovery process. would not be burned to completion. That is. if the dual streams were injected into the standard Claus reaction where burning occurs in presence of 1/3 air. the air will burn selec tivel; the HrS and leave some unburned NH3. NH3 could react and plug the catalvtic converter beds used to form free molten sulfur. To separate the NH3 and flare it separately poses environmental and energy wasting problems.

It is the primary object of this invention to provide an apparatus which can be used for the reactions of hydrogen sulfide with air and an organic sulfur compound fluid stream which may be contaminated with ammonia and/or hydrocarbons either liquid or gaseous for feeding a sulfur recovery process.

According to the present invention there is provided apparatus for burning a first fluid stream containing hydrogen sulfide and a second fluid stream containing an organic sulfur compound into a product suitable for recovery of free sulphur therefrom. comprising: (a) a reactor housing having an internallv insulated cvlindrical chamber of substantially constant diameter and defining an inlet end and an outlet end, the interior chamber being divided into a combustion zone followed by a downstream reaction zone.

(b) a first burner being positioned axially through a central opening at the inlet end and including means to pass a selected minor portion of said first fluid stream containing hydrogen sulfide therethrough: (c) a second burner being positioned in the annular space surrounding the first burner and including means to supply thereto the second fluid stream containing an organic sulfur compound: (d) air inlet and plenum means being provided to supply combustion air into the annular space remaining around the first burner and downstream of the combustion zone: (e) plural injection means being provided to the interior of said reactor, said injection means being spaced circumferen tially about the housing, and including means for injecting the remaining portion of said first fluid stream containing hydrogen sulfide through said injectiOn means.

The present invention will be further illustrated. by way of example, with refer ence to the accompanying drawings, in which: Figure 1 illustrates in cross-section one embodiment of an apparatus.

Figures 2 and 3 provide specific details of a burner arrangement at the inlet end of the reactor.

Figures 4 and 5 show two different embodiments of the gas distribution in the hydrogen sulfide burner.

Figure 6 is another embodiment of the burner of this invention.

Referring now to the drawings and in particular to Figure 1, there is shown in a cross-section one embodiment of the reactor, indicated generally by the numeral 10.

The burner assembly is shown in outline at the inlet (left) end of the reactor and is indicated generally by the numeral 12 of which Figures 2 and 3 show greater detail. A first combustion chamber of the reactor is indicated generally by the numeral 14. and the second reaction chamber is indicated generally by the numeral 16.

The reactor typically is a cylindrical metal housing 18 with the gas inlet portion at the left end, at flange 20, and the outlet indicated by the flange 22 at the right end.

The reactor combines in one self-contained apparatus the combustion space 14. into which at one end is introduced a portion (e.g., 10-35C,zc) of a hydrogen sulfide gas stream through a central burner and 100ass of any organic sulfur compound which may be contaminated with ammonia and/or hydrocarbons through a single or plurality of nozzles (see Figure 2) in the annulus between the hydrogen sulfide burner tip and the burner tile opening. A liquid stream containing any organic sulfur compound which may be contaminated with ammonia and/or hydrocarbons can be injected through a single nozzle to the center of the central burner 60 as shown in Figure 6. The ignited fluids first react in space 14 with substantially stoichiometric oxygen and an excess of oxygen.As will be described in connection with Figures 2 and 3. additional burners in the annulus are provided for the combustion of fuel gas. The burner assembly is mounted on a flange 20 at the inlet end of the reactor 18).

The burner opening is a cvlindrical tube 27 having an opening 36 formed of heat resistant tile into which the burner assembly is inserted. and supported on the flange 20.

There is an annular plenum chamber 19 surrounding the tube 27 with an air inlet pipe 28. Air is introduced into the plenum in accordance with the arrow 3(). The reactants are under pressure above atmospheric because of pressure losses in the reactor. the waste heat boiler and zither downstream equipment.

Air from the plenum 19 enters through a plurality of openings 32 in the cylinder 27 and flows into the combustion chamber through the annulus between the burner 12 and the burner tile opening 36 at the left end of the combustion space 14. The air, hydrogen sulfide and any organic sulfur compound which may be contaminated with ammonia and/or hydrocarbons mix and rapidly react to provide a hot gaseous atmosphere in the space 14 in the first chamber. These hot flue gases pass on through the interface 21 between the first chamber 14 and the second chamber 16.

Downstream of the interface 21 is a nozzle or nozzles 48 which inject the remaining portion of the hydrogen sulfide gas stream. This gas is rapidly heated and partiallv reacted by the hot products of combustion from the first chamber 14 to form a resultant stream suitable for feeding a sulfur recovery process. The retention time in the second chamber 16 is sufficient to make the resultant gases satisfactory for feeding to the usual conversion processes of sulfur recovery. These vapors and gases are then passed through a typical waste heat boiler and a Claus reaction process well known in the art. See. for example. Hydrocarbon Processing Vol 47 No 9 pages 248252 September 1968, for a description of various Claus processes.

Other practical features of reactors of this type such as sight glasses and weather protection means and appropriate types of thermal insulation. etc.. are provided, but are not described in detail, since they are well known in the art and their particular type forms no part of this invention.

Referring now to Figure 2 there is shown one embodiment of the burner assembly indicated generally by the numeral 12. This comprises a plate 61 which is adapted to be fitted to, and supported on the flange 20 of the reactor. This carries a central pipe 60 through which hydrogen sulfide is supplied as indicated by the arrow 64. At the downstream end of this pipe is a burner indicated generally by the numeral 62, which will be described in detail in conjunction with Figures 4 and 5. This burner is mounted axiallv in the opening 36 in the brick wall of the first chamber 14 of the reactor. If the reactant is liquid a central nozzle X should be installed.

At the outlet of the burner, as will be explained in conjunction with Figures 4 and 5. the hydrogen sulfide passes out of the burner 62 in the form of a series of individual streams or as a thin sheet of hydrogen sulfide at high velocity in the form of a spreading conical sheet. Air, under pressure as indicated by the arrows 46.

passes in the annulus along the stream of hydrogen sulfide 44 so that there is turbulent and rapid mixing and burning of the hydrogen sulfide.

In the annulus between the central burner 62 and the face 31 of the opening 36, there is a plurality of individual nozzles 76 and 78 (only two shown), which are connected respectively to two circular manifolds 70 and 72. One of these manifolds is connected to a supply of any organic sulfur compound contaminated with ammonia and/or organic sulfur gaseous compounds which, for example, could be introduced through a pipe 74 m accordance with arrow 75. The nozzles are supported on pipes equally spaced around the periphery. The second manifold 72 might be supplied with fuel gas through means indicated generally by the dashed line 80. Connected to this second manifold are a plurality of nozzles 78 which are positioned alternately between the nozzles 76 as shown in Figure 3.In addition there is a pilot burner 68 which is supported by a pipe means 66, for initially igniting the fuel nozzles.

Referring now to Figures 4 and 5 there are shown two embodiments of a burner tip indicated generally by the numeral 62. for the introduction of hydrogen sulfide into the first chamber 14.

The pipe 60 has an outwardly expanding conical portion 84. The end of the pipe is closed by a conical plate 89 which is a diverter, for diverting the stream of hydrogen sulfide into the annular space 88 about the periphery of the spreader 89. The hydrogen sulfide flows in accordance with the arrows 85 and 87, in the form of a conical sheet of high velocity gas. or as a plurality of individual streams lying along a conical surface. The diverter 80 is supported to the pipe 60 by means of a plurality of rods 86 which may be circular or rectangular in cross-section.

Insulating material 90 is generally provided over the front face of the diverter in order to protect it from the intense heat of the flame in the chamber 14.

When the flow of hydrogen sulfide is relatively large and a large opening is required, the annular opening 88 shown in Figure 4 is utilized. When the flow of hydrogen sulfide is small, an improved method of construction of the burner tip is as shown in Figure 5. Here the diverted is supported to the flange 84 by means of a spacer strip 96 with a plurality of openings 94 spaced circumferentially about the burner tip. The hydrogen sulfide flows in accordance with arrows 92 through these openings in the form of a plurality of jets of high velocity hydrogen sulfide in a general expanding conical wall. Where the flow is such that a very large number of openings is required to provide a minimum pressure drop across these openings. then the annular type of openings shown in Figure 4 is to be preferred.Any spacing of the annular gap 88 can be provided by positioning the rods 86 in anticipation of the desired gas flow. Other embodiments can be utilized for supporting the diverter on a central rod-like means and adjusting the longitudinal position of the diverter, to adjust the length of the gap 88. as desired. to accommodate different magnitudes of hydrogen sulfide flow.

Fuel gas is supplied to the peripheral burners in the annular space around the hydrogen sulfide burner for the purposes of preheat of the reactor at startup time or for supplemental heat in burning lean acid gas streams. Because the operation of the reactor to accomplish minimum pollutants in the atmosphere, and maximum recovery of sulfur. require critical temperature maintenance inside of the chambers. it is important that in starting up. the reactor be warmed to the proper temperature with a fuel.

A typical example of a process using a reactor of the type shown would be provided with acid gas of a total of 187 mols per hour. Of this. approximately 30% or 49 mols per hour would go into the central hydrogen sulfide burner 60 and the remaining 138 mols per hour would flow through the circumferential nozzles 48 at the interface 21. A gas containing ammonia, of which there are 23 mols per hour, would flow through one manifold 70 and set of four (for example) nozzles 76. A total of 447 mols per hour of combustion air would be required. A temperature of about 3000"F and retention time of .33 seconds would be present in the first chamber 14 and a temperature of about 2500"F. and retention time of .67 seconds would be present in the second chamber 16.

Although in the example given the total retention time was (1) second in the reactor this is by way of example only and not limiting. The retention time is typically divided: 1/3 in the first chamber and 2/3 in the second chamber. This is variable, however. depending upon the characteristics of the contaminating fluid stream which needs to be completely burned in the first chamber.

This design may be employed for burning liquid sulfur-bearing compounds. Liquid sulfur-bearing compounds will be injected through nozzle 61 located in the center of the hydrogen sulfide burner 62. The liquid will be atomized into combustion air stream 46 and will be ignited by hydrogen sulfide gas injected in burner 60 and mixed with air stream 46 as generally shown in Figure 1 by line 44.

The remaining volume of the hydrogen sulfide stream is injected at the interface into the second chamber.

Claims (7)

WHAT WE CLAIM IS:

1. Apparatus for burning a first fluid stream containing hydrogen sulfide and a second fluid stream containing an organic sulfur compound into a product suitable for recovery of free sulfur therefrom. comprising: (a) a reactor housing having an internally insulated cylindrical chamber of substantially constant diameter and defining an inlet end and an outlet end, the interior chamber being divided into a combustion zone followed by a downstream reaction zone; (b) a first burner being positioned axially through a central opening at the inlet end and including means to pass a selected minor portion of said first fluid stream containing hydrogen sulfide therethrough:: (c) a second burner being positioned in the annular space surrounding the first burner and including means to supply thereto the second fluid stream containing an organic sulfur compound; (d) air inlet and plenum means being provided to supply combustion air into the annular space remaining around the first burner and, downstream of the combustion zone; (e) plural injection means being provided to the interior of said reactor, said injection means being spaced circumferentially about the housing. and including means for injecting the remaining portion of said first fluid stream containing hydrogen sulfide through said injection means.

2. Apparatus as claimed in claim 1.

including a pluralitv of said second burner means circumferentially spaced in said annular space.

3. Apparatus as claimed in claim 1 or 2 including a plurality of separate fuel gas burners circumferentially spaced in said annular space.

4. Apparatus as claimed in claim 1. 2 or 3, including means in said annular space to ignite said fluid streams.

5. Apparatus as claimed in any preceding claim, in which said selected minor portion is aproximately 30ass of said first fluid stream containing hydrogen sulfide.

6. Apparatus as claimed in any preceding claim including a wall having an outlet orifice of smaller diameter than the interior of said chamber, said wall being positioned immediately upstream of said plural injection means

7. Apparatus for burning a first fluid stream containing hydrogen sulfide and a second fluid stream containing an organic sulfur compound into a product suitable for recovery of free sulfur therefrom, substantially as hereinbefore dEscribed with reference to and as illustrated in the accompanving drawings.