APPARATUS AND METHOD FOR QUENCHING A HOT GAS

Abstract: A vessel for quenching gases having a temperature in excess of 1100 DEG C by contact with an aqueous corrosive liquid (30) comprising: an upper vessel wall portion (22) lined with a hot face material capable of withstanding hot dry gas at temperatures in excess of 1100 DEG C; a lower vessel wall portion (35) in contact with an aqueous corrosive liquid (30); and a membrane wall portion (21) located within a vessel wall (35) proximate an anticipated liquid/gas interface level, the membrane wall having internal channels (26) for circulating a cooling fluid.

Description: APPARATUS AND METHOD FOR QUENCHING A HOT GAS The invention relates to methods and apparatus for cooling a hot gas exiting a gasification reactor vessel at temperatures in excess of 1300°C, wherein the gas comes into contact with corrosive aqueous liquid. Related inventions include a prior patent application for a Method and Apparatus for the Production of One or More Useful Products from Lesser Value Halogenated Materials, PCT international application PCT US/98/26298, published 1 July 1999, international publication number WO 99/32937. The PCT application discloses processes and apparatus for converting a feed that is substantially comprised of halogenated materials, especially byproduct and waste chlorinated hydrocarbons as they are produced from a variety of chemical manufacturing processes, to one or more "higher value products" via a partial oxidation reforming step in a gasification reactor. In the processes described in the prior application, gases exiting the gasifier section are at high temperatures, for example approximately 1400°C to 1450°C, and contain significant concentrations of hydrogen halide. Cooling of these gases is described as preferably taking place in a hydrogen halide quench, with a recirculated, cooled aqueous liquid vigorously contacting the hot gases to effect the desired cooling. Cold, concentrated aqueous hydrochloric acid is mentioned as a useful quench liquid, and a variety of quench apparatus are described, including an overflow weir quench. Briefly, a weir quench is a vessel having one or more short vertical weir cylinder(s) that penetrate a lower flat plate. The lower flat plate forms a partition between an upper and a lower chamber. Quench liquor flows into an annular volume created between side vessel walls and the central cylinder(s), and above the flat plate. The liquor preferably is managed to continually overflow the top of the cylinder(s) and to flow down the inside walls of the cylinder(s) (thus, the term "overflow weir quench"). When, simultaneously, a hot gas is directed to flow down tlirough the vessel and through the cylinder(s), into a region below, the co-flow of liquid and the gas, with liquid evaporating as it cools the gas, creates an intimate mixing and cooling of the gas stream. An inventory of liquid around the weir, in such an embodiment, can serve as a reservoir in the event of a temporary interruption of liquid flow. Liquid overflow of a weir quench, as discussed above, can operate in one of three regimes, with the middle regime being preferable. In a first regime, a low liquid flow rate could be insufficient to fully wet the inner wall of the weir cylinder(s). In a second and preferred regime, the liquid flow rate is sufficient to fully wet the weir cylinder inner wall and create a full liquid curtain, but is not so great as to completely fill a cross section of the weir. That is, a gas flow area would still be available down the weir diameter. In a third operating regime liquid flowrate might be so high that a back-up of the liquid occurs, to a point that the weir functions as a submersed orifice. One problem with using an overflow weir quench as described above and as described in the prior application lies in providing suitable materials for the quench vessel walls. Materials must be found that can withstand both the corrosive effect from a hot dry gas environment and also withstand a corrosive liquid aqueous environment. Wall portions exposed to both a corrosive aqueous liquid and a hot gaseous stream are subject to severe corrosive action. Thus, the materials selected for areas of a quench vessel wall that come • into contact with a gas/liquid interface are of critical importance. The instant invention provides several methods and apparatus for solving the above materials problems so as to minimize vessel wall corrosion. In one aspect, the invention includes an improved quench vessel (of a weir quench or other design) for receiving a gas at temperatures greater than 1100°C, and for contacting the gas with an aqueous corrosive liquid therein, such as aqueous hydrogen halide liquid. The vessel preferably includes upper wall portions lined with a hot face material. Hot face materials are well known in the art and include materials such as Al 2 O 3 , refractory brick, and refractory materials capable of withstanding hot dry temperatures such as in the range of 1450°C. The vessel preferably includes a pressure wall or shell and may further include a jacketing over the pressure wall or shell to help control exterior vessel wall temperatures, at least for the hottest upper regions of the vessel. Preferably a quench vessel upper region also includes inner lower wall portions comprised of a carbon-based material, SiC material or other non-metal materials suitable for containing a corrosive aqueous liquid. In one embodiment of the instant invention (see Fig. 9 and accompanying description below), a membrane wall is located upon an inner vessel wall proximate a liquid/gas interface level. The liquid/gas interface level in a quench may vary somewhat. However, the level should be able to be predicted to within a height range which may run a few feet for some embodiments at commercial scale. A membrane wall is comprised of tubing that provides internal channels for circulating a cooling fluid. Alternately, a carbon block or ring wall can be located upon an inner vessel wall proximate a liquidgas interface, with the block providing internal passageways for circulating a cooling fluid, like the membrane wall above (see Fig. 4 and accompanying description below). With the membrane or carbon block wall, the inner wall surface remains dry. In a further dry wall embodiment, a SiC, graphite, silica or similar material block or ring is located on the inner vessel wall proximate, above and below a liquid/gas interface (see Fig. 12 and description below). Contact of the ring below the liquid/gas interface with the liquid cools upper portions of the block or ring by heat transfer through the SiC, graphite, silica or like material such that wetted portions above the interface also remain below approximately 1000°C, a temperature at which the aforementioned materials can sufficiently withstand corrosion, notwithstanding contact with the hot gas. In another embodiment of the instant invention, a graphite ring wall can be located upon an inner vessel wall, proximate a liquid/gas interface level, with the ring in communication with and having ports for discharging a cooling fluid therethrough. Such ring and ports are structured to discharge cooling fluid substantially down the inside vessel wall below the ports and above the interface. A graphite ring can include a graphite splash baffle (ref. Fig.6) attached to the inner vessel wall and extending inwardly over the ring ports. In an alternate embodiment, the vessel can include a porous seeping ceramic wall (sometimes referred to in the art as a "weeping wall") located upon the inner vessel wall proximate a liquid/gas interface level, with the ceramic wall being in communication with a source of cooling fluid for communicating the cooling fluid therethrough (see Fig. 10 and description below). The cooling fluid seeps or passes through the wall and down the inside wall surfaces, cooling the wall and forming a liquid curtain over inside wall surfaces. Seeping discharge is limited to desired wall surface portions by finishing or coating to an impermeable state ceramic wall surfaces not desired to seep. In another aspect, the invention includes apparatus for quenching a hot corrosive gaseous stream with a temperature of at least 1300°C, comprising a quench vessel in fluid communication with a source of the gaseous stream and which receives the gaseous stream and contacts the gaseous stream with an aqueous liquid, and a means located between the source and the quench vessel for cooling the gaseous stream to below 1100°C in a dry environment. The means for cooling can include a radiant cooler, a convective cooler or a dry spray quench. The invention also includes methods for quenching a hot gaseous stream that includes receiving a gaseous stream at temperatures in excess of 1100°C into a quench vessel, cycling a corrosive aqueous liquid into the quench vessel and cooling vessel wall portions around a liquid/gas interface level with a cooling fluid, the cooling fluid either circulated interior to the wall or discharged over interior wall surfaces. In an alternate embodiment, the invention includes a dry environment method for quenching a hot corrosive gaseous stream comprising receiving a corrosive gaseous stream at temperatures greater than 1300°C, cooling the gaseous stream to below 1100°C in a dry environment and then cooling the gaseous stream further to temperatures of less than 200°C by contacting the gas with an aqueous liquid within a quench vessel. A better understanding of the present invention can be obtained when the following detailed descriptions of preferred embodiments are considered in conjunction with the following drawings, in which: Figure 1 is a block flow diagram of an embodiment of a gasification process, in general, for halogenated materials. Figure 2 illustrates an embodiment of a gasifier for use in a gasification process for halogenated materials, as per Figure 1. Figure 3 illustrates a embodiment for a quench and particle removal unit, in general, for use in a gasification process for halogenated materials, as per Figure 1. Figure 4 illustrates an embodiment of the present invention showing an internally- cooled carbon block or ring located in vessel wall portions proximate a liquid/gas interface level. Figure 5 illustrates a graphite ring embodiment for the instant invention. Figure 6 illustrates a graphite splash baffle for use with a graphite ring, as illustrated in Figure 5. Figure 7 schematically illustrates the use of a radiant cooler between a gasification reactor vessel and a quench vessel. Figure 8 schematically illustrates the use of a dry spray quench between a gasification reactor vessel and a quench vessel. Figure 9 illustrates a weir quench having a membrane cooled wall located proximate a liquid/gas interface level. Figure 10 illustrates a vessel embodiment having a porous ceramic wall located proximate a liquid/gas interface level in a vessel. Figure 11 illustrates in schematic fashion the use of a convective cooler between a reactor vessel and a quench vessel. Figure 12 illustrates a non-cooled dry wall interface material embodiment of the instant invention. An embodiment of a gasification process for halogenated materials is discussed first, for background purposes, as it offers a particularly apt application for the instant invention. The illustrative gasification process is of a type as described in the prior related PCT application, and is comprised of five major processing areas, as illustrated in the block flow diagram of Figure 1. 1) Gasifier 200 2) Quench 300 3) Particulate Removal and Recovery 350 4) Aqueous HC1 Recovery and Clean-up 400, 450 5) Syngas Finishing 700 Review of the gasification embodiment helps to place the instant invention in perspective. The embodiment presumes a chlorinated organic (RO) feed. The gasifier area 200 of a preferred embodiment, as more particularly illustrated in Figure 2 and discussed in more detail below, consists of two reaction vessels, R-200 and R- 210, and their ancillary equipment for the principal purpose of reforming the halogenated material, presumed herein to be RCl's. The liquid RC1 stream 144 is atomized into a primary reactor R-200, preferably with a pure oxygen stream 291 and steam stream 298. In a harsh gasification environment the RCl's and other organic constituents are partially oxidized and converted to carbon monoxide, hydrogen chloride and hydrogen, with lesser amounts of water vapor and carbon dioxide being produced as well as trace elements including soot (essentially being carbon). The gaseous stream from R-200 preferably flows into a secondary reactor R-210 where all reactions proceed to completion, thus yielding very high conversion efficiencies for all halogenated species and minimizing undesirable side products, such as soot. Hot gases from the secondary reactor R-210 are preferably cooled in a quench area 300 by direct contact with a circulating aqueous stream. The reactor effluent syngas and recirculating aqueous stream are most preferably intimately mixed in a weir quench vessel. The mixture then preferably flows to a vapor-liquid separator drum from which a quenched gaseous stream passes overhead and a bottoms liquid is cooled and recycled to the weir quench. Particulates in the gaseous stream passing overhead from the quench vapor-liquid separator, consisting primarily of soot, with minor amounts of metals and metal salts, are preferably scrubbed from the gaseous stream in an atomizer or scrubber. The gaseous stream from the vapor-liquid separator scrubber is subsequently preferably introduced into an HC1 absorption column 400. A gaseous stream of noncondensible syngas components passes through the absorber overheads and on to a syngas finishing area 700. HC1 in the syngas stream introduced into the absorber is absorbed to form a concentrated aqueous acid bottoms stream. This high quality aqueous acid stream is preferably filtered and passed through an adsorption bed 450 to remove final traces of impurities, yielding a high quality aqueous HC1 product suitable for sales or internal use. A caustic scrubber and syngas flare system make up at least portions of syngas finishing area 700. The caustic scrubber, or syngas finishing column, uses cell effluent in the lower section of the column to absorb final traces of HC1 from the syngas stream. At this point the gas can be piped to the final consumer. Having reviewed now an embodiment of a gasification reactor process for halogenated materials in general, offering a prime use for the instant invention, the gasifier 200 will be reviewed in slightly more detail, as illustrated in Figure 2, and the products of the gasification process will be briefly discussed. Gasifier area 200, in a particularly preferred embodiment, as discussed above, consists of two reaction vessels R-200 and R-210 and their ancillary equipment for the principal purpose of halogenated feed material reformation. Primary gasifier R-200, in the preferred embodiment illustrated, functions as a down fired, jet stirred reactor, the principal purposes of which is to atomize the liquid fuel, evaporate the liquid fuel, and thoroughly mix the fuel with oxygen, moderator, and hot reaction products. The gasifier operates at approximately 1450°C and 5 bars gauge (75 psig). These harsh conditions insure near complete conversion of all feed components. The secondary gasifier R-210 in the preferred embodiment functions to allow the reactions for the primary gasifier to proceed to equilibrium. The secondary gasifier R-210 operates at approximately 1400°C and 5 barg (75 psig). This is simply a function of the conditions established in the primary gasifier, less limited heat loss. The following represents typical operating performance of the gasifier system with respect to production of species other than the desired CO, H 2 , and HCl: Exit gas CO 2 concentration: 1.0 - 10.0 volume percent Exit gas H O concentration: 1.0 - 10.0 volume percent The following example is provided for background. Example 1 The following feed streams were fed to a gasifier in accordance with the above embodiment through an appropriate mixing nozzle: Chlorinated organic material: 9037 kg/hr Oxygen (99.5 percent purity): 4419 kg/hr Recycle vapor or moderator: 4540 kg/hr [58.8 wt percent water vapor, 41.2 wt percent hydrogen chloride] The resulting gasification reactions resulted in a synthesis gas stream rich in hydrogen chloride and chamber conditions of approximately 1450°C and 5 barg. In accordance with the above embodiment, the following vapor stream might be fed to a quench vessel: 41,516 lb/hr (38.5 wt percent CO, 37.3 wt percent HCl, 10.8wt percent CO 2 , 8.9wt percent N 2 , 1.7wt percent H 2 ). The functionality of a quench requires that a heat balance be maintained and that the liquid flowrate remains approximately within an appropriate range as described above. This range might be approximately 500 gpm to 1500 gpm for an acceptable quench performance in accordance with the above described gasification process embodiment. The quench operates at gasifier system pressure, which might be approximately again 5 barg (75 psig). Inlet temperature would be anticipated to be normally about 1400°C and exit temperature about 100°C. Quench liquid flow would be anticipated to be about 6400 liters/minute (1400 gpm) at 60°C from a cooler at base design conditions for a gasification process embodiment above described. Quench liquid supplied to a weir quench is preferably a circulating solution. The two-phase stream that exits a weir quench chamber is anticipated to flow to a vapor-liquid separator. Liquid droplets would be separated from the vapor stream - allowing a relatively liquid-free vapor to pass overhead into a particulate scrubbing system. Collected liquid can be pumped through a graphite plate and frame heat exchanger or other suitable exchanger and back to the weir quench as quench liquor. This exchanger rejects the heat duty of quenching the gas from 1400°C to approximately 100°C - which is approximately 37 MM kJ/hr (35 MMBTU/hr) at base conditions. The circulation rate and exchanger outlet temperature can be varied to achieve a desired quench outlet temperature within operational constraints of a weir device as described above, and within the boundaries further defined by the water balance and contaminant removal efficiencies. Due to vigorous gas-liquid contact in a quench, the scrub liquid is very near equilibrium with the gas phase. Make-up liquor for the system can come from a particulate scrubber, which is at a high enough HCl concentration to avoid absorbing HCl from the gas, but rather letting it pass through where it can be captured as saleable acid in the absorber. Literature as well as experimental data reveal that conventional materials used in a quench system, such as described above, show signs of corrosion at the vapor/liquid interface in the vessel. Either a material needs to be found that can hold up to these conditions or an alternative means needs to be devised in order to ensure that corrosion is not as severe and unrelenting a problem at this interface in a quench system during operation. The instant invention teaches solutions to this problem. A first preferred embodiment of the instant invention, as illustrated in Figure 4, comprises a cooled carbon or graphite block or ring 20, inserted as a liquid/gas interface material into a wall portion of vessel 18 proximate an anticipated liquid/gas interface area. Block or ring 20 is inserted into the vessel wall at approximately the level of the top of weir 36 in the weir quench embodiment, which is where the gas/liquid interface level should occur. The block might be two to three feet in height to adequately cover possible interface levels. The height of the block and situation of the block in the vessel wall should be selected to cover anticipated gas/liquid interface levels for the vessel. Upper inside wall portions of vessel 18, such as wall 22 indicated in Figure 4, include hot face materials. Hot face materials include materials capable of facing hot gases, such as hydrogen halide gases at temperatures of approximately 1450°C. Suggested hot face materials include Al 2 O 3 , or high alumina refractory brick. Nessel 18 hot face wall may also be covered with an insulating brick outside of the hot face refractory brick, as more clearly indicated in Figure 9. As indicated in Figure 9, in one embodiment a hot alumina refractory brick comprising an upper wall portion of vessel 18, might be 4 l A inches (11.43 cm) thick and of greater than 90 percent Al O 3> while an outer insulating brick might be approximately 9 inches (22.86 cm) thick. The lower cooler vessel region could be covered with an acid tile of approximately VA inches (3.81 cm) thick. Nessel 18 might also be covered with a pressure vessel or shell such as carbon steel coated with chilastic CP79 or the equivalent. The pressure vessel might also be jacketed. Lower portions of the upper region of vessel 18 are portions anticipated to be covered by the quench cooling liquid, such as an aqueous hydrogen halide liquid, so are preferably comprised of a material able to withstand corrosion from contact with the liquid acid. The lower portions 32 of vessel 18 wall might be comprised of silicon carbide or SiC 4 . Lower vessel walls 34 leading to an outlet of vessel 18 might be comprised of acid brick or ceramic lining materials. Plate 37 through which weir 36 extends might preferably be formed of a reaction bonded silicon carbide, while weir 36 might preferably be comprised of quartz or silicon carbide. Figures 9 and 4 illustrate possible vessel wall construction. Returning to the embodiment of Figure 4, block 20 has passages 26 within for circulating a small amount of cooling fluid 28, possibly recycled aqueous hydrogen halide liquid. Preferably, passages 26 in block 20 circulate cooling liquid 28 near the inside surface of the block in order to keep the block wall temperature normally less than 450°C. The graphite or carbon block 20 defines conduits or passages 26 that allow a cooling fluid or liquid to flow through the wall while the inside surface of the block itself remains dry. The liquid 28 used to cool the wall preferably discharges from passages 28 into a vessel liquid retaining area 30, below an anticipated liquid level in the vessel. A second embodiment, illustrated in Figure 9 (not drawn to scale), includes a cooled membrane wall 21. A membrane wall is known in the art of refractory design. A membrane wall typically employs one or more layers of a refractory 35 upon a tubular membrane 21 construction. The membrane can be constructed of any number of conduits or passages 26 (usually helically wound tubes, or similar) for circulating a fluid heat control substance. The conduits together make up an interior "membrane" barrier. The membrane and refractory materials are installed within the vessel, usually in panels, (typically leaving a small space between the membrane and a vessel wall). A heat transfer fluid flows through the membrane conduits to absorb heat from quench chamber 24, thereby limiting vessel wall temperatures. The conduits of a membrane are typically formed of an alloy, such as Hastelloy Alloy B-2, C-276, Tantalon or similar. The membrane is typically faced with a castable or plastic refractory as refractory layer 35. A third embodiment, illustrated in Figure 5, includes a cooled carbon or graphite distribution ring 19. Graphite ring 19 is placed upon an interior vessel 18 wall above an anticipated liquid/gas interface level. The ring preferably contains small ports 60 and one or more passageways 33 that enable cooling liquid 28 to pass through the wall and ring and to run down the inside of the ring wall, which keeps the wall wet and cooled. The cooled liquid, for example aqueous hydrogen halide liquid, initially passes through channel(s) 33 and flows inward to a quench liquid distribution area. Liquid 28 flows from the outside to the inside of the ring structure and then through ports 60 and runs down the surface of the ring wall, preventing hot process gases from contacting the graphite wall. The fluid flow in ports 60 transfers heat from, and cools, the dry wall region immediately above ports 60. The liquid then collects in the liquid collection area 30 of the vessel. Figure 6 illustrates a possible addition to the third embodiment, namely a cooled distribution ring 19 having a graphite baffle 15. In addition to a cooled ring 19, where liquid 28 overflows down a side of the wall keeping the wall cool and wet along an anticipated gas/liquid interface, a baffle 15 is placed above the area where the liquid is distributed, for preventing the liquid from splashing onto the dry wall 22 portion above. A fourth embodiment illustrated in Figure 10 is analogous to the embodiment of Figure 5. The embodiment of Figure 10 illustrates a seeping porous ceramic wall block or ring 20. Cooling liquid 28 is placed in communication with a portion of the seeping porous ceramic material. Pumping of cooling liquid 28 through conduit 33 to seeping porous ceramic wall 20 causes the cooling liquid to seep through the porous ceramic wall and emerge on inside portions of the wall where, as with the embodiment of Figure 5, the liquid flows down the inside surface of the seeping porous ceramic wall, so wetting and cooling the wall and keeping the wall out of contact with the hot dry process gas. As with the embodiment of Figure 5, the cooling liquid after seeping tlirough the porous ceramic wall and falling down the wall surface collects in a cooling liquid collection area 30 of the vessel 18. Surfaces of the block or ring that are not desired to seep are finished, as with a film 39, to render them impermeable. A fifth embodiment illustrated in Figure 12 comprises a non-cooled hot wall. A block or ring 20 of SiC of graphite or silica or the like is placed at, above and below the interface level 80. Contact with the liquid below interface level 80 cools the block above the interface level, through heat transfer within the block itself, to temperatures within the block material's capacity to withstand a wet corrosive environment. The block is sufficiently high such that the wall above the block is dry. In a distinct approach, a sixth embodiment, as schematically illustrated in Fig. 7, includes a conventional radiant cooler 48 situated between a gasifier vessel 50 and a quench vessel 18. The radiant cooler 48 is placed in an exiting section of a gasifier reactor 50 or is employed in a separate vessel. The purpose of this system is to cool the gaseous stream temperature leaving reactor 50 below 1093°C. The significance of the cooler gas temperature is that there are known materials of construction that can be used for a downstream quench vessel 18 which can withstand this environment in both the vapor and liquid phase, and so the quench vessel design modifications described above for the vapor/liquid interface may not be necessary. (In general, herein, 1093°C may be rounded to 1100°C for convenience; 1100°C is an approximate number. ) The radiant cooler 48 is basically a heat exchanger and preferably uses boiler feed water or other conventional heat transfer fluids for cooling the gas stream from gasifier 50. A convective cooler, illustrated in schematic in Figure 11, could be used in a similar manner for this cooling application, with appropriate consideration given to control tube wall temperatures in the cooler 70. A distinct, alternate approach (not shown) to providing intermediate cooling would be to add sufficient cooled, recycle synthesis gas from the synthesis gas finishing area 700 to bring down the bulk temperature of the gases proceeding to the quench vessel 18 to about 1100°C. In an eighth embodiment, similar to the sixth and seventh embodiments and illustrated schematically in Fig. 8, a dry spray quench 72 is situated between a reactor vessel 50 and a quench vessel 18. Spray nozzles inserted in an exiting section of the gasification reactor 50, or in a separate vessel, cool the gaseous stream leaving the reactor 50 to below 1093°C by evaporation of a portion of the cooling medium 28 (again preferably being recycled aqueous quench liquid). The spray nozzles are in either case preferably selected, arranged and oriented so that droplets of the liquid 28 sprayed into the gaseous stream substantially do not impinge on a dry wall of the exiting section nor any dry refractory surface. Again, the significance of the cooler gas temperature is that there are known materials of construction for a downstream quench vessel that can withstand this environment in both a vapor and a liquid phase. It is preferred in all embodiments to keep the pressure vessel wall temperature of vessel 18 above around 200°C, in order to prevent hydrogen halide vapors from condensing on the wall and in the process leading to possibly significant corrosion. From a review of the above embodiments it can be seen that while currently known materials of construction cannot easily withstand the conditions of both a hydrogen halide vapor and liquid environment at the extreme temperatures of the reactor (1450°C), the techniques of the instant invention provide solutions to the problem of corrosion from the vapor and liquid environment in a subsequent vessel, such as a quench vessel, largely allowing the use of a known materials of construction for the vessel. Embodiments that modify the vessel wall construction, at least at the liquid/gas interface level, have the advantages of eliminating a need for an upstream cooling system, such as spray nozzles or radiant cooling or convective cooling. Those embodiments create intimate gas/liquid mixing for thorough quenching with a simple yet robust construction. In a weir quench vessel capacity can be increased or decreased by varying the diameter or the number of weir tubes. Solutions embodying weir quench vessel construction wall designs further offer a strictly limited, controlled liquid/vapor interface area. The interior cooled graphite ring or block design and the cooled membrane wall design are vessel design solutions wherein internal cooling passages maintain dry gas contacting skin temperatures at acceptable levels. The exterior cooled distribution ring or seeping porous ceramic wall produce a solution of vessel design that provides for limiting hot gas contact with wet wall portions. The surface is kept cool and protected due to the heat transfer action of flowing liquid over the inside surface of the graphite wall. The radiant cooler, convective cooler and spray nozzle concepts, in contrast, offer the advantages of greatly simplifying vessel wall material of construction selection, even for the critical vapor/liquid interface area. The principal purpose of the cooler or nozzle is not heat recovery but rather temperature control for subsequent combination of the gaseous stream with a quench vessel downstream from a reactor. The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials, as well as in the details of the illustrated system may be made without departing from the spirit of the invention. The invention is claimed using terminology that depends upon a historic presumption that recitation of a single element covers one or more such elements, and recitation of two elements covers two or more of the element in question.

Claims: WHAT IS CLAIMED IS: 1. A vessel for quenching gases having a temperature in excess of 1100°C by contact with an aqueous corrosive liquid, comprising: an upper vessel wall portion lined with a hot face material capable of withstanding hot dry gas at temperatures in excess of 1100°C; a lower vessel wall portion in contact with an aqueous corrosive liquid; and a membrane wall portion located within a vessel wall proximate an anticipated liquid/gas interface level, the membrane wall having internal channels for circulating a cooling fluid. 2. A vessel for quenching gases having a temperature in excess of 1100°C by contact with an aqueous corrosive liquid, comprising: an upper vessel wall portion lined with a hot face material capable of withstanding hot dry gas at temperatures in excess of 1100°C; a lower vessel wall portion in contact with an aqueous corrosive liquid; and a carbon block wall portion located within a vessel wall proximate an anticipated liquid/gas interface level, the block having internal passageways for circulating a cooling fluid. 3. A vessel for quenching gases having a temperature in excess of 1100°C by contact with an aqueous corrosive liquid, comprising: an upper vessel wall portion lined with a hot face material capable of withstanding hot dry gas at temperatures in excess of 1100°C; a lower vessel wall portion in contact with an aqueous corrosive liquid; and a graphite ring wall portion, located within a vessel wall proximate an anticipated liquid/gas interface level, the ring being in communication with, and having ports for discharging, a cooling fluid therethrough. 4. The vessel of claim 3 wherein the ring and ports are structured to discharge cooling fluid substantially down vessel wall portions below the ring. 5. The vessel of claim 4 that includes a graphite splash baffle attached to a vessel wall and extending inwardly over the ring ports. 6. A vessel for quenching gases having a temperature in excess of 1100°C by contact with an aqueous corrosive liquid, comprising: an upper vessel wall portion lined with a hot face material capable of withstanding hot dry gas at temperatures in excess of 1100°C; a lower vessel wall portion in contact with an aqueous corrosive liquid; and a porous ceramic wall portion located within a vessel wall proximate an anticipated liquid/gas interface level, the porous ceramic wall being in communication with a source of cooling fluid for communicating fluid therethrough. 7. A vessel for quenching gases having a temperature in excess of 1100°C by contact with an aqueous corrosive liquid, comprising: an upper vessel wall portion lined with a hot face material capable of withstanding hot dry gas at temperatures in excess of 1100°C; a lower vessel wall portion in contact with an aqueous corrosive liquid; and a wall portion comprised of graphite or silica located within a vessel wall at, above and below an anticipated liquid/gas interface level. 8. The vessel of claims 1, 2, 3 or 6 wherein the cooling fluid includes an aqueous hydrogen halide liquid. 9. The vessel of claims 1, 2, 3 or 6 wherein the cooling fluid is recirculated liquid from a downstream vessel of the process. 10. The vessel of claim 8 wherein the hydrogen halide liquid includes hydrogen chloride. 11. The vessel of claims 1 , 2, 3, 6 or 7 wherein the hot face material includes Al 2 O 3 . 12. The vessel of claims 1, 2, 3, 6 or 7 wherein the hot face material includes a refractory brick. 13. The vessel of claims 1, 2, 3, 6 or 7 that includes a pressure vessel shell substantially enclosing the vessel. 14. The vessel of claim 13 that includes a jacket substantially surrounding at least upper regions of the pressure vessel shell. 15. Apparatus for quenching a hot gaseous stream having a temperature in excess of about 1300°C, comprising: intermediate cooling means located between a source of the hot gaseous stream and a quench vessel for cooling the gaseous stream to below 1100°C; and a quench vessel for receiving the gaseous stream from the intermediate cooling means and contacting the gaseous stream with a corrosive aqueous liquid. 16. The apparatus of claim 15 wherein the intermediate cooling means includes a radiant cooler. 17. The apparatus of claim 15 wherein the intermediate cooling means includes a dry spray quench. 18. The apparatus of claim 15 wherein the intermediate cooling means includes a convective cooler. 19. The apparatus of claim 17 wherein the intermediate cooling means is in fluid communication with a cooling fluid. 20. The apparatus of claim 19 wherein the cooling fluid includes liquid recycled from a downstream process. 21. The apparatus of claims 1, 2, 3, 6, 7 or 15 wherein the quench vessel includes a weir quench. 22. A method for quenching hot gas, comprising: receiving gas at temperatures in excess of 1100°C into a quench vessel; discharging a corrosive aqueous liquid into the quench vessel; and cooling vessel wall portions around an anticipated liquid/gas interface level with a cooling fluid. 23. The method of claim 22 that includes cooling by passing a cooling fluid within wall portions. 24. The method of claim 22 that includes cooling by passing a cooling fluid down inside surfaces portions of a vessel wall. 25. The method of claim 22 that includes cooling with a cooling fluid that includes an aqueous hydrogen halide liquid. 26. A method for quenching hot gas, comprising: receiving gas at temperatures in excess of 1100°C into a quench vessel; discharging a corrosive aqueous liquid into the quench vessel; and providing a vessel wall portion at, above and below an anticipated liquid/gas interface level including a graphite or silica material. 27. A method for quenching hot gas, comprising: receiving hot gas from a reactor vessel at temperatures in excess of 1300°C; cooling the hot gas to below 1100°C; and communicating the cooled gas to a quench and further cooling the gas to temperatures of below 200°C, through contacting the gas with a corrosive aqueous liquid. 28. The method of claim 27 that includes cooling the hot gas with a radiant cooler. 29. The method of claim 27 that includes cooling the hot gas with a dry spray quench. 30. The method of claim 27 that includes cooling the hot gas using hydrogen halide gas. 31. The method of claim 27 that includes contacting the gas with aqueous hydrogen halide liquid.

Inventors: ECKERT WILLIAM M, GALLOWAY CONNIE M, JEWELL DENNIS W, MALL KENNETH W, SALINAS LEOPOLDO III, TIMM EDWARD E, ECKERT, WILLIAM, M., GALLOWAY, CONNIE, M., JEWELL, DENNIS, W., MALL, KENNETH, W., SALINAS, LEOPOLDO, III, TIMM, EDWARD, E.
Applicants: DOW GLOBAL TECHNOLOGIES INC, ECKERT WILLIAM M, GALLOWAY CONNIE M, JEWELL DENNIS W, MALL KENNETH W, SALINAS LEOPOLDO III, TIMM EDWARD E, DOW GLOBAL TECHNOLOGIES INC., ECKERT, WILLIAM, M., GALLOWAY, CONNIE, M., JEWELL, DENNIS, W., MALL, KENNETH, W., SALINAS, LEOPOLDO, III, TIMM, EDWARD, E.
Application year: 2001
Main classification: F28C3
IPC codes: B01J3, B01J19, F28C3, F28F19, F28F21