Abstract: To provide a pulverized coal burner capable of reducing the NOx concentration at the time of a low load, a pulverized coal burner includes a secondary air nozzle and a tertiary air nozzle concentrically positioned about the outer periphery of a fuel nozzle carrying a pulverized coal with a primary air, and two swirling flow generators are included at least one of these nozzles with a positional relation parallel to a flow of air. One of the swirling flow of the two swirling flow generators can be set strongly. And, under a condition of low air flow rate, air can be supplied from one swirling flow generator alone. Since the swirling strength of the combustion air can be increased, the concentration of NOx produced by the combustion of the pulverized coal can be reduced. Also, because the swirling strength at the time of low load can be increased, the NOx concentration can be reduced by keeping the pulverized coal flame stable.

Abstract: A catalyst unit is constructed by alternately stacking rectangular catalyst elements (1) formed by cutting catalyst support plates coated with a catalytic material and having ribs (2) inclined at 45.degree. to one specified side edge (1a) of each thereof, and those turned upside down in a case, and the catalyst unit is disposed in a gas passage with the ribs (2) of the catalyst elements (1) inclined at an angle greater than 0.degree. and smaller than 90.degree. to the direction of the gas flow (6). When the catalyst unit comprising the catalyst elements (1) coated with a denitrating catalyst is placed in the gas passage, the ribs (2) of the catalyst elements (1) blocks the gas flow (6) and generate turbulent currents on the downstream side thereof to promote the contact of ammonia and NOx contained in the exhaust gas with the catalyst.

Abstract: Exhaust gas from combustion equipment such as a boiler is brought into contact with an absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid. Limestone particles having larger diameters are selectively retained in a zone wherein the absorbing liquid that has absorbed the sulfur oxide from the exhaust gas is neutralized. The absorbing liquid containing water and the gypsum thereby formed, as main constituents, are selectively drained from the neutralizing zone and recycled for renewed contact with the exhaust gas. Because of the possibility of a large decrease of desulfurizing performance due to a variation in the load on the boiler, etc., at least one of the following is monitored: pressure drop across the neutralizing zone, torque of a stirring device, solids concentration in the absorbing liquid, specific gravity of the absorbing liquid and viscosity of the absorbing liquid. Responsive to the monitored parameters outlet SO.sub.

Abstract: A coal gasification furnace includes a gasification chamber for producing therein a burnable gas from coal, a burner arranged on a side wall of the gasification chamber so as to inject coal and an oxidizing agent along a peripheral direction of the gasification chamber, a slag cooling chamber provided below the gasification chamber, and a slag tap partitioning the gasification chamber and the slag cooling chamber. The slag tap has a hole formed in a shape whereby the central portion of the hole is generally circular and oppositely directed slits extend outwardly from the central portion of the hole.

Abstract: This invention provides a ferritic heat-resistant steel having excellent HAZ softening resistance characteristics and exhibiting a high creep strength up to a high temperature of not lower than 500.degree. C., and a method of producing such a steel, the steel comprising in terms of mass %, 0.01 to 0.30% of C, 0.02 to 0.80% of Si, 0.20 to 1.50% of Mn, 0.50 to 5.00% of Cr, 0.01 to 1.50% of Mo, 0.01 to 3.50% of W, 0.02 to 1.00% of V, 0.01 to 0.50% of Nb, 0.001 to 0.06% of N, one or both of 0.001 to 0.8% of Ti and 0.001 to 0.8% of Zr, wherein a value (Ti+Zr) in (Cr, Fe, Ti, Zr) of a M.sub.23 C.sub.6 type carbide in the steel is 5 to 65%, and the present invention provides a method of producing the same.

Abstract: A coal gasifier has an inner wall surface made by metal of an inlet part of a heat recovery vessel, the inlet part having a inner cooling mechanism, and gas for peeling deposits on the inner wall surface is injected from plural gas injection holes, the injected gas forming a slewing flow and further being intermittently increased. And at least one cooling medium injection nozzle is provided at a side wall in the upper part of a gasification chamber.

Abstract: An apparatus preventive maintenance having a driving mechanism capable of driving a jet nozzle 24 to cause it to travel upward-and-downward, to rotate and to swing is settled on the top of a housing in the bottom portion of a reactor pressure vessel and on a hole for a fuel support piece, water pumped by a high pressure pump is spouted from a jet nozzle, and cavitation bubbles generated during the spouting are supplied to the positions to be treated for preventive maintenance, such as housings in the bottom portion of the reactor pressure vessel. Therewith, the residual tensile stress in the position to be treated is improved in a releasing direction by the energy generated by the collapsing of the cavitation bubbles.

Abstract: According to the apparatus and method, combustible gas having a stable composition can be formed even if the load is charged. Burners are provided in the upper and the lower regions of an entrained bed coal gasification reactor. The temperature of the product gas is kept low in the upper region and high in the lower region. The volumes of the upper and lower regions are changed to meet the load so that the rate of heat loss becomes constant even if the load changes. Since the rate of heat loss can be kept constant and consequently variation of the composition of the product gas can be suppressed small, the efficiency of the coal gasification electric power generating system can be kept constant.

Abstract: A wet-type flue gas desulfurization method and plant making use of a solid desulfurizing agent in which exhaust gas exhausted from a combustion apparatus such as a boiler is brought into contact with absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid followed by neutralization of the absorbing liquid containing the sulfur oxide thus absorbed. The solid desulfurizing agent is selectively retained in an absorbing liquid neutralizing zone and the absorbing liquid, containing water as a main constituent and solid products formed from the absorbed sulfur oxide, is selectively removed from the neutralizing zone. In the neutralizing zone the upward flow of the absorbing liquid, optionally augmented by an upward flow of air or water, forms a fluidized bed of limestone particles, thereby preventing coating of the limestone by gypsum and thereby retaining reactivity of limestone.

Abstract: A pulverized coal combustion burner includes a pulverized coal nozzle, and secondary and tertiary air nozzles provided in concentric relation to the pulverized coal nozzle. A flame stabilizing ring is provided at an outlet end of the pulverized coal nozzle. A separation wall is provided within the pulverized coal nozzle to divide a passage in this nozzle into two passages. A pulverized coal/air mixture flows straight through the two passages, so that recirculation flows of the pulverized coal/air mixture are formed in proximity to the outlet end of the pulverized coal nozzle. As a result, the ignitability of the pulverized coal, as well as a combustion rate, is enhanced, thereby reducing the amount of discharge of NOx.

Abstract: An ultrasonic flaw detecting apparatus for efficiently detecting a flaw existing in a deep portion of a multi-layer structure includes a first sensor arranged so as to transmit an ultrasonic wave into a different property layer surrounded by a medium having a different acoustic impedance in the multi-layer structure, a function generator for generating a pulse-shaped sine wave, a power amplifier for amplifying and supplying the pulse-shaped sine wave to the first sensor, a second sensor arranged so as to receive a boundary echo from the different property layer, a first amplifier for amplifying the boundary echo received by the second sensor, an intensity detector for judging the intensity of an amplified signal of the boundary echo, a third sensor arranged so as to receive an echo from a flaw inside a layer in a deep portion of the different property layer, a second amplifier for amplifying the flaw echo received by the third sensor, a recorder for recording the amplified flaw echo signal, and a control unit

Abstract: In fuel gasification, particles of, for example, coal and an oxidant are supplied to a reactor, where the coal particles are gasified. The gas thus produced may contain molten slag entrained therein and such slag could subsequently solidify and affect other components of the coal gasification apparatus. Therefore a molten slag cooling heat exchanger is positioned directly above the reactor and this cools the gas so as to cause any molten slag therein to solidify. Hence, such molten slag does not reach an evaporator above the molten slag cooling heat exchanger, so that the efficiency of the evaporator will be maintained. However, solidified molten slag may build up on heat exchange tubes of the molten slag cooling heat exchanger. Therefore, the rate of coolant supplied to the molten slag cooling heat exchanger is varied, to cause expansion and contraction which causes solidified slag to be dislodged. Hence the efficiency of the molten slag cooling heat exchanger does not deteriorate.

Abstract: A method of and apparatus for detecting an abnormality of a fluidized bed boiler is characterized in that an abnormality of the fluidized bed boiler is detected on the basis of a physical quantity related to a condition change of a gas existing in a space defined by a pressure vessel and the fluidized bed boiler accommodated within the pressure vessel.

Abstract: An elongated absorber housing, including an inlet duct and an outlet duct, is integrally provided on an upper portion of a circulation tank. The absorber is a self-supporting structure supported by only the circulation tank. At least the furthest upstream spraying stage in a spraying zone in the inlet duct includes spray pipes provided with spray nozzles for spraying an absorbing liquid in a direction cocurrent with gas flow, and at least the furthest downstream spraying stage includes spray nozzles for spraying the absorbing liquid in a direction countercurrent to the gas flow. The absorber is an integral structure in which the upper portion of the circulation tank forms a part of the duct, whereby the absorber is self-supportable and, moreover, is of a simple structure, giving it high strength and eliminating of the need for provision of fitments for supporting the absorber.

Abstract: A system of preventive maintenance for plant component parts correlates parameters for determining the transition probability distribution of degradation phenomena, selects an arbitrary influencing factor with respect to each of various influencing factors of the degradation phenomena, selects one of the parameters for the transition probability distribution as a first function, and sets the transition probability distribution when the variables of various influencing factors are reference degree values of a reference system. The system computes a ratio between the first function and the parameter value in the reference system to give a function of the subdivided index of degradation of the influencing factor, multiplies the subdivided index of degradation of various influencing factors by a unit conversion and a coefficient for reliability.

Abstract: An excellent welding tip in the feed stability of a wire, in the release capacity of foreign matter, and in the stability of current control, and a process for manufacturing such a tip economically, is achieved in accordance with a sectional shape of a guide hole opened and provided to a welding tip. The sectional shape is derived by forming a wire in a passable non-circular shape. The sectional shape of the guide hole may be a polygonal or elliptic shape, or approximately so. In the case of making the sectional shape of the guide hole polygonal, it is more preferable to make it a polygon circumscribing on a circle, for example, such a polygon circumscribing on a larger circle than the outer diameter of the wire to be inserted into the guide hole by 0.02-0.20 mm in diameter. Specifically, it is preferable to arrange the sectional shape as a triangle.

Abstract: A finned tube comprises a tube; and a fin strip having fins formed by forming slits of a predetermined length in a fin portion of a strip and at predetermined intervals, and a base portion in which no slit is formed, and wound around the tube so that the fins thereof extend substantially radially of the tube. The fins are twisted at a twist angle in the range of 2.degree. to 40.degree. to a contact line along which the base portion of the fin strip is in contact with the tube, and inclined at an inclination angle in the range of 2.degree. to 20.degree. to a straight line perpendicular to the axis of the tube. A heat exchanger is provided with a plurality of such finned tubes, and a heat recovery apparatus comprises such a heat exchanger disposed in a combustion gas passage.

Abstract: Low temperature water in a low temperature water tank 12 installed outside a reactor pressure vessel 9 is pumped by a high pressure pump 15 and supplied through a conductor 17 under pressure. The supplied water is ejected, as a stream of cold water jet 8, from a nozzle 14 connected to the conductor 17 and introduced into the reactor pressure vessel 9 by a driving mechanism. The stream of cold water jet 8 ejected from the nozzle 14 is directed to impinge against a predetermined position of a core shroud 13 in reactor water 11 filled in the reactor pressure vessel 9 and being at temperature higher than the low temperature water. Then, while continuing to eject the cold water jet 8 from the nozzle 14, the nozzle 14 is moved away from the predetermined position, or the ejection of the cold water jet 8 from the nozzle 14 is stopped, allowing the predetermined position to be heated again with the temperature of the reactor water 11.

Abstract: A target practice apparatus which allows a trainee to shoot at a target on a moving image with live bullets. The target practice apparatus includes a screen on which a training image is projected, three or more acoustic sensors for detecting an impact sound, impact coordinate measuring section for computing the coordinates of an impact position on the screen based on detection signals from the acoustic sensors, a projector, a playback unit for supplying the projector with an image signal, a recording medium which stores a hit image and a miss image as well as the training image, a memory unit in which a hit range and a miss range are previously stored for each frame of the training image, and a data processing and controlling section which compares the detected coordinates of the impact position with data of the hit range and the miss range stored in the memory unit to perform a hit/miss judgment, selects the hit image or the miss image based on the results of the judgment, and reproduces the selected image.

Abstract: In a pressurized fluidized bed boiler, furnace means is divided into at least two separate furnaces: a furnace with an evaporator and a superheater disposed therethrough, and a furnace with the superheater and a reheater disposed therethrough. The furnaces are accommodated in separate pressure vessels, respectively. Air is supplied into the pressure vessels through air pipes connected to the pressure vessels, where it is used for pressurizing the pressure vessels, and then supplied into the furnaces through their lower portions, where it is used as a combustion air. An oxygen concentration meter is mounted in an exhaust gas pipe in an outlet of the furnace, and an air flow rate adjusting valve 3 is mounted outside each of the pressure vessels.