Abstract: Apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler comprises plural vertical, impact type particle separators made of cooling tubes located within the CFB in a plurality of staggered rows. One embodiment employs a plurality of stacked, slip fit elements having apertures which accept the cooling tubes. The slip fit elements cooperate with one another to form a collecting channel, typically U-shaped, which separates particles from flue gases conveyed across the particle separators. Shiplap joints in between the individual slip fit elements prevent gas and solids from leaking therebetween and allow for thermal expansion. Alternatively, the impact type particle separators comprise cooling tubes connected to one another to form a unitary structure. Pin studs welded to the cooling tubes and covered with a coating of refractory; ceramic tiles; metal or ceramic spray coatings; metal or ceramic castings; weld overlay; and/or shields provide erosion resistance.

Abstract: Processes for producing aromatic monomers useful for forming polyesters are disclosed. Cost effective steps employed in the processes permit small amounts of process-related materials typically removed from monomer to remain in an aromatic monomer product. In many cases, the presence of the process-related materials left in the monomer product by the cost effective process steps can enhance the performance of the monomer in certain applications.

Abstract: A combined, integral steam generator coal gasifier includes a vertically elongated, all welded, gas tight enclosure with a burner zone having a double pitch sloping furnace floor and a slag tap extending therethrough. Successive zones located above the burner zone are provided with appropriate tube materials for conveying synthesis gas produced by the coal gasification process. A multi-pass convection pass zone having upflow and downflow passes is located at an upper portion of the enclosure and contains a plurality of superheater (primary and secondary) as well as economizer heating surfaces which extract heat from the synthesis gas to produce steam. An ash remover is connected to the outlet of the convection pass zone to remove ash from the synthesis gas exiting from the convection pass zone. The slag tap located at the bottom of the burner zone communicates with a slag tank or a drag chain deasher for receiving and removing slag from the burner zone.

Abstract: Processes for producing aromatic monomers useful for forming polyesters are disclosed. Cost effective steps employed in the processes permit small amounts of process-related materials typically removed from monomer to remain in an aromatic monomer product. In many cases, the presence of the process-related materials left in the monomer product by the cost effective process steps can enhance the performance of the monomer in certain applications. Aromatic monomer products and polymers produced therefrom having these advantages also are disclosed, as well as products such as pasteurizable bottles made from these polymers.

Abstract: A system that is usable with a stack of fuel cells that have cell terminals includes a circuit and scanning units. The circuit provides a selection signal that indicates selection of at least one of the fuel cells for a voltage measurement. The scanning units are coupled to the stack to establish different groups of the fuel cells. Each group is associated with a different one of the scanning units, and each scanning unit has a ground that is referenced to a different one of the cell terminals. Each scanning unit is adapted to, in response to the selection signal, measure and indicate a voltage of each selected fuel cell within the group of fuel cells associated with the scanning unit.

Abstract: A system that is usable with a stack of fuel cells that have cell terminals includes scanning units and a circuit. The scanning units are coupled to the stack and establish different groups of the fuel cells. Each scanning unit has a ground that is referenced to a different one of the cell terminals, and each scanning unit is adapted to measure the voltages of the fuel cells in an associated one of the groups and indicate the measured voltages. The circuit is adapted to communicate with the scanning units to receive the indicated voltages.

Abstract: A weldless connection system for U-beam particle separators is provided in which one end of each U-beam is provided with sides and a back that are separated from each other forming tabs. The tabs may be bent, or folded, about 90.degree. inward toward the channel formed by the U-beam. The back tab may be twice as long as the side tabs, and the extra half length of the tab can be folded about 180.degree. back at the back of the U-beam in a double thickness. Each tab has a hole therethrough. The double-length back tab has two holes; one hole is provided through each half. When the tabs are bent inward, the holes align. A bolt and washer placed through the aligned holes may be used to secure the tabs, and thus the U-beam, to a furnace roof structure. An alternate embodiment of the invention is provided in which only the sides of the U-beam form tabs which extend past the bottom of the U-beam.

Abstract: A circulating fluidized bed (CFB) reactor or combustor having an internal impact type primary particle separator which provides for internal return of all primary collected solids to a bottom portion of the reactor or combustor for subsequent recirculation without external and internal recycle conduits. The CFB reactor enclosure or furnace is provided with plural furnace outlets. This construction permits increased furnace depths and reduced furnace widths, resulting in a compact design.

Abstract: An improved CFB reactor or combustor arrangement has at least a first and a second group of impact type particle separators or U-beams with cooling surfaces located adjacent and immediately upstream of the second group of U-beams which serve to cool flue gas/solids flowing through the CFB before it reaches the second group of U-beams. By reducing the gas temperature in the vicinity of and entering the second group of U-beams, the U-beams can be made of less expensive materials and are thus less expensive to produce and maintain. The heat absorbed by the local cooling surfaces can be applied to heat a working fluid supplied to a turbine or other process.

Abstract: Bed temperature in a circulating fluidized bed (CFB) reactor is controlled by varying a recirculation rate of particles collected by a secondary particle separator back to the CFB reactor. Particle storage means, sized to contain sufficient inventory required for bed inventory/temperature control due to fuel/sorbent variations and/or load changes, stores particles collected by the secondary particle separator. The storage means can be either directly below the secondary particle separator or at a remote location. Particles collected by the secondary particle separator rather than by the primary particle separator are preferred due to their smaller size and lower temperature. A bed temperature control system controls the recirculation rate of these particles back to the reactor. Level sensing devices are provided on the storage means. A solids storage level control system that interacts with the bed temperature control system controls the solids inventory in the storage means via a purge system.

Abstract: A CFB reactor or combustor having an internal impact type primary particle separator provides cavity means and particle return means in an upper portion of the reactor enclosure to obtain direct and internal return of all primary collected solids to a bottom portion of the reactor or combustor for subsequent recirculation without external and internal recycle conduits.

Abstract: There are provided methods for monitoring the oligomeric content of prepolymers and polymers, which methods employ high-performance liquid chromatographic techniques. Typically, the methods of the present invention may be used to determine the oligomeric content of polyethylene terephthalate polymers and prepolymers.

Abstract: A process is disclosed for preparing polyethylene terephthalate having a predetermined intrinsic viscosity which involves the direct esterification of terephthalic acid with ethylene glycol followed by the polycondensation of the esterification product using a polycondensation catalyst system containing cobalt, manganese-, and antimony-containing components.

Abstract: An internal particle separator having impingement members positioned within the furnace enclosure across and just upstream of the furnace exit opening. These impingement members are organized into at least two staggered rows that are positioned to fully cover the exit opening thereby allowing entrained particles to strike the impingement members and free-fall directly back into the fluidized bed to increase its density. A baffle plate is attached to the lower end region of the impingement members thereby obstructing the vertical gas passage between these members.

Abstract: Aqueous solutions of crude terephthalic acid are purified by hydrogenation in the presence of plural noble metal catalysts in separate layers. Initially, the solution to be purified is passed through a layer of ruthenium-on-carbon catalyst, rhodium-on-carbon catalyst, or platinum-on-carbon catalyst, and thereafter through a layer of palladium-on-carbon catalyst. Optionally, the purified aqueous terephthalic acid solution can be treated further to decrease the 4-carboxybenzaldehyde content thereof by passing it through a layer of rhodium-on-carbon catalyst downstream from the palladium-on-carbon catalyst layer.

Abstract: A process is disclosed for producing cyclized aromatic compounds by the liquid-phase air oxidation of 2-methyl-substituted biphenyls and diphenylmethanes in an acetic acid medium in the presence of a cobalt-manganese-bromine catalyst or a zirconium-cobalt-manganese-bromine catalyst wherein the mole ratio of cobalt-to-manganese is about 1.0:0.1 to about 1.0:10.0 and the ratio of zirconium-to-cobalt is about 0.005:1.0 to about 0.20:1.0, and mole ratio of bromine to total metals of said cobalt-manganese-bromine catalyst or zirconium-cobalt-manganese-bromine catalyst is from about 0.2:1.0 to about 20.0:1.0, which process comprises conducting the reaction in a batch process at a temperature of from 75.degree. C. to about 250.degree. C. at a pressure of from 1 to 100 atmospheres, or continuously in two stages comprising a first-stage reaction at a temperature of about 75.degree. C. to about 200.degree. C. and a second-stage reaction at a temperature of about 150.degree. C. to about 250.degree. C.

Abstract: A process is disclosed for producing cyclized aromatic compounds by the liquid-phase air oxidation of 2-methyl-substituted biphenyls and diphenylmethanes in an acetic acid medium in the presence of a cobalt-manganese-bromine catalyst or a zirconium-cobalt-manganese-bromine catalyst wherein the mole ratio of cobalt-to-manganese is about 1.0:0.1 to about 1.0:10.0 and the ratio of zirconium-to-cobalt is about 0.005:1.0 to about 0.20:1.0, and mole ratio of bromine to total metals of said cobalt-manganese-bromine catalyst or zirconium-cobalt-manganese-bromine catalyst is from about 0.2:1.0 to about 20.0:1.0, which process comprises conducting the reaction in a batch process at a temperature of from 75.degree. C. to about 250.degree. C. at a pressure of from 1 to 100 atmospheres, or continuously in two stages comprising a first-stage reaction at a temperature of about 75.degree. C. to about 200.degree. C. and a second-stage reaction at a temperature of about 150.degree. C. to about 250.degree. C.

Abstract: A process for producing fiber grade terephthalic acid is disclosed. In this process impurities having high molecular weight are eliminated by hydrogenation comprising the following steps: (a) treating an aqueous solution containing at least about 1 percent of said impure terephthalic acid with hydrogen at a temperature in the range of about 300.degree. F. to about 450.degree. F. and at a pressure sufficient to maintain the solution in the liquid phase in the presence of a supported or unsupported metallic Group VIII noble metal catalyst wherein both the metal and support components are insoluble in the solution at the temperature and at a hydrogen partial pressure of from about 30 to about 300 pounds per square inch; (b) separating the treated solution from the catalyst; (c) crystallizing terephthalic acid from the separated solution while retaining impurities and the reduced aromatic compounds dissolved in the resulting mother liquor at a temperature in the range of about 100.degree. F. to about 450.degree.

Abstract: An article suitable for use in the adhesive joining of two optical fibers with low light loss comprises a tubular container an inner surface of which is coated with a release agent and/or is composed of an inherently releasing material, which is larger in cross-section at the ends than at a central region, the smaller central region being where the ends of the fibers are joined.

Abstract: A method is disclosed for separating and measuring the fluorescence of 4-carboxy-p-terphenyl in crude terephthalic acid formed by the liquid-phase oxidation of p-xylene in a solvent.