Abstract: An object is to provide a gate valve capable of preventing operational deficiencies caused by particulate materials accumulating in a valve box, thus providing superior sealing properties and high durability, having a simple structure, and allowing inspection and maintenance to be performed easily.

Abstract: The present invention provides a mercury removal system and method for effectively removing a mercury component, which is present in a gas stream in an extremely small amount in wet gas cleaning used for coal or heavy oil gasification, petroleum refining and the like. The mercury removal system in wet gas cleaning comprises a water washing tower for introducing therein a target gas containing a mercury component and transferring the mercury component into an absorbing solution, a flush drum (10) for flushing the absorbing solution discharged from the water washing tower to separate the absorbing solution into a gas component and waste water, an oxidation treatment means (1) for adding an oxidizing agent to the absorbing solution at the preceding stage of the flush drum, and a waste water treatment means for subjecting to coagulation sedimentation treatment the separated waste water containing the mercury component at the following stage of the flush drum to dispose of the mercury component as sludge.

Abstract: An object is to provide a gate valve capable of preventing operational deficiencies caused by particulate materials accumulating in a valve box, thus providing superior sealing properties and high durability, having a simple structure, and allowing inspection and maintenance to be performed easily.

Abstract: A secondary heat exchanger B for recovering latent heat from combustion gas includes water tubes 5 each of which is so inclined that a first end 50a is positioned lower than a second end 50b. Therefore, in draining water from each of the water tubes 5, water can be caused to flow smoothly into a water-inflow and hot-water-outflow header 6A connected to the first ends 50a. The secondary heat exchanger B includes a casing 7 which includes an upper wall 70a and a bottom wall 70b which are so inclined that the inner surfaces thereof extend generally in parallel with the water tubes 5, and the upper and the lower gaps 79a and 79b have constant widths s2 and s3. Therefore, the amount of heat recovery from the combustion gas passing through the gaps 79a and 79b can be increased.

Abstract: A secondary heat exchanger B for recovering latent heat from combustion gas includes water tubes 5 each of which is so inclined that a first end 50a is positioned lower than a second end 50b. Therefore, in draining water from each of the water tubes 5, water can be caused to flow smoothly into a water-inflow and hot-water-outflow header 6A connected to the first ends 50a. The secondary heat exchanger B includes a casing 7 which includes an upper wall 70a and a bottom wall 70b which are so inclined that the inner surfaces thereof extend generally in parallel with the water tubes 5, and the upper and the lower gaps 79a and 79b have constant widths s2 and s3. Therefore, the amount of heat recovery from the combustion gas passing through the gaps 79a and 79b can be increased.

Abstract: A combustion apparatus (1) is generally composed of a principal part (5), a supplementary part (6) and a burner port assembly (3). Four metal plates (7,8,10,11) constituting the principal and supplementary parts (5,6) are pressed to have in them several protuberances and recesses. These metal plates are laid one on another to form in them some hollow spaces and sealed regions. These hollow spaces communicate with each other to form a thin gas passage (22) together with a thick gas passage (73) in this combustion apparatus (1) in such a manner that its condition of thick and thin fuel combustion is rendered more stable.

Abstract: A combustion apparatus (1) with a burner port assembly (3) comprises an elongated first array of main burner ports (53) for jetting and burning a fuel gas mixture of a concentration to make main flames. The combustion apparatus (1) comprises at least one second arrays of auxiliary burner ports (63) for jetting and burning a further fuel gas mixture of a different concentration to make auxiliary flames, wherein the second arrays of said auxiliary burner ports (63) extend along the first array of said main burner ports (53). The burner port assembly (3) is constructed using inner and outer wall segments (52) together with outermost wall segments (52a,52f) or bands (58). One of the bands (58) faces the corresponding one of said outermost segments (52a,52f) so as to define between them collateral burner ports (61a,61b).

Abstract: A combustion apparatus (1) is generally composed of principal part (5), a supplementary part (6) and a burner port assembly (3). Four metal plates (7,8,10,11) constituting the principal and supplementary parts (5,6) are pressed to have in them several protuberances and recesses. These metal plates are laid one on another to form in them some hollow spaces and sealed regions. These hollow spaces communicate with each other to form a thin gas passage (22) together with a thick gas passage (73) in this combustion apparatus (1) in such a manner that its condition of thick and thin fuel combustion is rendered more stable.

Abstract: A combustion apparatus (1) with a burner port assembly (3) comprises an elongated first array of main burner ports (53) for jetting and burning a fuel gas mixture of a concentration to make main flames. The combustion apparatus (1) comprises at least one second arrays of auxiliary burner ports (63) for jetting and burning a further fuel gas mixture of a different concentration to make auxiliary flames, wherein the second arrays of said auxiliary burner ports (63) extend along the first array of said main burner ports (53). The burner port assembly (3) is constructed using inner and outer wall segments (52) together with outermost wall segments (52a,52f) or bands (58). One of the bands (58) faces the corresponding one of said outermost segments (52a,52f) so as to define between them collateral burner ports (61a,61b).