Abstract: SO2 and/or NOx are removed from gaseous CO2 at elevated pressure(s) in the presence of molecular oxygen and water and, when SO2 is to be removed, NOx, to convert SO2 to sulfuric acid and/or NOx to nitric acid. The sulfuric acid and/or nitric acid is/are then removed from the gaseous carbon dioxide to produce SO2-free, NOx-lean carbon dioxide gas. The invention has particular application in the removal of SO2 and/or NOx from carbon dioxide flue gas produced in an oxyfuel combustion process, for example, in a pulverized coal fired power station.

Abstract: An improved control scheme is set forth for an adsorption process that removes water and carbon dioxide (CO2) from a feed gas using a hybrid of both temperature swing (i.e. TSA) and pressure swing (PSA) to regenerate the adsorbent. The control scheme comprises adjusting the quantity of heat to be provided by the regeneration gas as a function of temperature data taken within a strategic portion of the water selective adsorbent zone. The strategic portion corresponds to the location for the desired transition from regeneration by temperature swing, to regeneration by pressure swing. In a preferred embodiment of the present invention, said quantity of regeneration heat is also adjusted as a function of the water content of the feed gas.

Abstract: A divided wall exchange column includes a dividing wall strengthened by stiffening members and/or a double wall design to better withstand pressure differentials and minimize temperature differentials. When a double wall is used, cost of manufacture and installation is minimized by reducing the manufacturing tolerances required while providing a design robust in construction, installation, and operation. When structured packing is used, the stiffening members, combined with positioning the layers of packing at preferred angles relative to the dividing wall, result in minimal interference with the heat and/or mass transfer process while minimizing the complexity of manufacture and construction of the packing. Further, by positioning the top layer of structured packing at other preferred angles relative to the dividing wall, a simplified liquid distributor design may be used in the divided wall exchange column while the layers below may still be orientated as described above with all the associated benefits.

Abstract: Method gas liquefaction which comprises cooling a feed gas stream successively through at least two heat exchange zones, wherein cooling is provided by respective vaporizing refrigerants, and wherein the refrigerant in the coldest temperature range is only partially vaporized in the coldest heat exchange zone and then is vaporized in a further heat exchange zone at temperatures above the highest temperature of the coldest heat exchange zone to form a totally vaporized refrigerant. The totally vaporized refrigerant is compressed to yield a compressed refrigerant stream, and the entire compressed refrigerant stream is either (i) cooled by indirect heat exchange in the further heat exchange zone, thereby providing self-refrigeration for the recirculating refrigeration process, or (ii) cooled in a heat exchange zone preceding the coldest heat exchange zone by indirect heat exchange with a respective vaporizing refrigerant and then further cooled the in the further heat exchange zone.

Abstract: A process to convert heat into power is set forth wherein, to make the cycle more suitable to low grade heat, the working fluid remains substantially in the liquid state after being heat exchanged against the heat source and a dense fluid expander is used in place of a conventional vapor expander to subsequently work expand the liquid working fluid.

Abstract: An assembly in an exchange column includes a plurality of generally vertically adjacent layers of structured packing. Each layer includes a plurality of generally horizontally adjacent structured packing elements, each of which has an upper edge and a lower edge. Each layer has a top having a plurality of the upper edges and a bottom having a plurality of the lower edges. In a first layer of packing at least one of the upper edge and the lower edge is modified on at least one element. In a second layer of the packing, located vertically adjacent the first layer, the upper edges and the lower edges are unmodified on substantially all of the elements, whereby one of the unmodified upper edge and the unmodified lower edge on at least one of the elements in the second layer is adjacent one of the modified edges in the first layer.

Abstract: An assembly of trays in a divided wall column having an inner column wall, a dividing wall, and an interior space includes: a first tray having at least one radial downcomer adjacent the dividing wall and extending radially toward the inner column wall a first substantial distance, and a first liquid receiving area having a radial axis at a first angle to the dividing wall and extending radially toward the inner column wall a second substantial distance; and a second tray below the first tray, the second tray having at least one other downcomer having a radial axis at a second angle to the dividing wall and extending radially toward the inner column wall a third substantial distance, and at least one second liquid receiving area adjacent the dividing wall and extending radially toward the inner column wall a fourth substantial distance.

Abstract: A method and apparatus for designing perturbation signals to excite a number of input variables of a system, in order to test that system for the purpose of obtaining models for the synthesis of a model-based controller. The method begins with providing input parameters of the system. A plurality of binary multi-frequency (BMF) signals are generated based on these input parameters and the frequency spectra of these BMF signals are calculated. One BMF signal is selected out of the set of BMF signals so that the frequency spectrum of the selected BMF signal most closely matches a desired frequency spectrum specified by the input parameters. The selected BMF signal is used as a first perturbation signal for testing the system. The selected BMF signal is also shifted by predetermined amounts of samples to create delayed copies of the original BMF signal to be used as additional perturbation signals.

Abstract: Method for gas liquefaction comprising cooling a feed gas by a first refrigeration system in a first heat exchange zone and withdrawing a substantially liquefied stream therefrom, further cooling the substantially liquefied stream by indirect heat exchange with one or more work-expanded refrigerant streams in a second heat exchange zone, and withdrawing therefrom a further cooled, substantially liquefied stream. At least one of the one or more work-expanded refrigerant streams is provided by compressing one or more refrigerant gases to provide a compressed refrigerant stream, cooling all or a portion of the compressed refrigerant stream in a third heat exchange zone to provide a cooled, compressed refrigerant stream, and work expanding the cooled, compressed refrigerant stream to provide one of the one or more work-expanded refrigerant streams.

Abstract: Method for liquefying a gas which comprises cooling a feed gas stream successively through first and second temperature ranges to provide a liquefied product, wherein refrigeration for cooling the feed gas stream in the first temperature range is provided by a first vaporizing refrigerant and refrigeration for cooling the stream in the second temperature range is provided by a second vaporizing refrigerant, and further wherein an auxiliary refrigerant derived from the second vaporizing refrigerant provides additional refrigeration by vaporization at temperatures above a lowest temperature in the first temperature range.

Abstract: Gas compression system comprising a driver; a refrigerant compressor driven by the driver and having an inlet and an outlet; a relief pressure safety valve having an inlet in flow communication with the outlet of the compressor, an outlet, and a set point; and a recycle pressure safety valve having an inlet in flow communication with the outlet of the compressor, an outlet in flow communication with the inlet of the compressor, and a set point that is lower than the set point of the relief pressure safety valve.

Abstract: An adsorber vessel for use in the adsorption of a component from a gas and subsequent regeneration by thermally induced desorption of the component comprises an inlet for regeneration gas having an inlet nozzle containing at least one heater element, and an outlet for regeneration gas, the inlet and outlet for regeneration being separated by a flow path including a flow chamber containing a body of adsorbent, and wherein the body of adsorbent has a first end which is adjacent the inlet for regeneration gas and a second end which is remote from the inlet for regeneration gas, and the or each heater element is located so as not to penetrate through the first end of the body of adsorbent.

Abstract: A structured packing element has at least one edge adapted to intermesh with an edge of at least one other structured packing element. The structured packing elements may be used in a packed section in an exchange column which includes: a first layer of structured packing including a first structured packing element having an upper edge adapted to intermesh with a generally vertically adjacent lower edge of a second structured packing element; and a second layer of structured packing located above the first layer of structured packing, the second layer including the second structured packing element having the lower edge adapted to intermesh with the generally vertically adjacent upper edge of the first structured packing element. The upper edge of the first structured packing element intermeshes with the lower edge of the second structured packing element.

Abstract: A process and an apparatus related to the reduction of the level of a component in a feed gas such as air involving passing the gas to at least three parallel thermal swing adsorption zones charged with an adsorbent and operating according to an adsorption cycle, wherein the cycle of each zone is phased with respect to that of the other zones so that at any point during the cycle, the number of zones in the adsorption step is greater than the number of zones not in the adsorption step.

Abstract: An apparatus for collecting and redistributing a flow of a liquid descending in an exchange column containing a layer of structured packing and having a longitudinal axis, a cross-sectional area, and an inner wall having an inner perimeter, includes: a wall-flow collector located above the layer of structured packing, the wall-flow collector having an outer perimeter adjacent the inner perimeter of the inner wall and being adapted to collect at least a portion of the liquid descending on or near the inner wall of the exchange column; a transmission means for transmitting at least a portion of the collected liquid collected by the wall-flow collector toward the longitudinal axis a substantial distance across the cross-sectional area of the exchange column; and a dispensing means for dispensing at least a portion of the portion of the collected liquid from the transmission means to the layer of structured packing.

Abstract: A structured packing element has at least one edge adapted to intermesh with an edge of at least one other structured packing element. The structured packing elements may be used in a packed section in an exchange column which includes: a first layer of structured packing including a first structured packing element having an upper edge adapted to intermesh with a generally vertically adjacent lower edge of a second structured packing element; and a second layer of structured packing located above the first layer of structured packing, the second layer including the second structured packing element having the lower edge adapted to intermesh with the generally vertically adjacent upper edge of the first structured packing element. The upper edge of the first structured packing element intermeshes with the lower edge of the second structured packing element.

Abstract: Method for the rejection of nitrogen from condensed natural gas which comprises (a) introducing the condensed natural gas into a distillation column at a first location therein, withdrawing a nitrogen-enriched overhead vapor stream from the distillation column, and withdrawing a purified liquefied natural gas stream from the bottom of the column; (b) introducing a cold reflux stream into the distillation column at a second location above the first location, wherein the refrigeration to provide the cold reflux stream is obtained by compressing and work expanding a refrigerant stream comprising nitrogen; and (c) either (1) cooling the purified liquefied natural gas stream or cooling the condensed natural gas stream or (2) cooling both the purified liquefied natural gas stream and the condensed natural gas stream, wherein refrigeration for (1) or (2) is obtained by compressing and work expanding the refrigerant stream comprising nitrogen.

Abstract: Compressor system comprising (a) a first compressor having a first stage and a second stage wherein the first stage of the first compressor is adapted to compress a first gas and the second stage of the first compressor is adapted to compress a combination of a fourth gas and an intermediate compressed gas from the first stage of the first compressor; and (b) a second compressor having a first stage and a second stage wherein the first stage of the second compressor is adapted to compress a second gas and the second stage of the second compressor is adapted to compress a combination of a third gas and an intermediate compressed gas from the first stage of the second compressor. The first gas is at a first pressure, the second gas is at a second pressure higher than the first pressure, the third gas is at a third pressure higher than the second pressure, and the fourth gas is at a fourth pressure higher than the third pressure.

Abstract: Liquid is distributed substantially uniformly in a liquid-vapour separation column 22 located on an off-shore floating platform using a liquid distributor 24 characterised in that (i) the distance between the two apertures that are furthest apart in the or each secondary distributor is such that the liquid distributor provides, at each angle of tilt, a standard deviation of liquid flow rates through the apertures of the or each secondary distributor that is less than a first predetermined maximum for all angles of tilt; and (ii) the difference in flow rate between the aperture having maximum liquid flow and the aperture having minimum liquid flow in the or each secondary distributor at each angle of tilt is less than a second predetermined maximum for all angles of tilt.

Abstract: Refrigeration process for gas liquefaction which utilizes one or more vaporizing refrigerant cycles to provide refrigeration below about ?40° C. and a gas expander cycle to provide refrigeration below about ?100° C. Each of these two types of refrigerant systems is utilized in an optimum temperature range which maximizes the efficiency of the particular system. A significant fraction of the total refrigeration power required to liquefy the feed gas (typically more than 5% and often more than 10% of the total) can be consumed by the vaporizing refrigerant cycles. The invention can be implemented in the design of a new liquefaction plant or can be utilized as a retrofit or expansion of an existing plant by adding gas expander refrigeration circuit to the existing plant refrigeration system.