Flares types

Mechanical joints for copper tube up to inch outside diameter can be of the flare type, in which the tube end is coned out to form its own gasket. This must be carried out with the proper flare tools, and it may be necessary to anneal the tube to ensure that the resulting cone gasket is soft. 

Mark 5 Flares, Types 1 and 2 consisted of a cylindrical buoyancy chamber which contd two candles. To these were attached a fuze, a static cord and a pull igniter. The static cord functioned either the arming device of the fuze or the pull igniter. When the device was released (from a container) over the water it went under the surface and then came up. It floated with the head of the flare just clear of the water. When the 1st candle was about % burned out, a piece of safety fuse running to the 2nd candle was ignited and, after a short delay, die 2nd candle started to bum. Each candle burned for about 2% min... 

The theory of initiation has mainly been expounded in the field of solid-propellant ignition. A recent effort for pyrotechnics has been published by Johnson.The calculations are difficult since they involve calories transferred to the surface of the initiated column at certain temperatures and over a time interval heat absorption and flow in the main item, heat developed in the main item from the incipient final reaction, and, of course, heat losses. Johnson advocates on the basis of theoretical considerations a small area on which lire transfer is concentrated low thermal conductivity, density, and specific heat of the first fire and use of high-energy, flare-type first fire mixtures in such a way that radiant heat transfer is optimal. 

Double rotor chainmill-type crushers or double row cage mills are preferred. The discharge assembly of the mill should not be restricted and should be constructed of flexible rubber (conveyor belting) panels that can be flexed from the outside by an operator using a hammer. A flared-type discharge assembly for the crushers.is recommended to help avoid the accumulation of solids. The crushed oversize should be recycled to the oversize screen on a closed-loop basis to ensure that only the fine-material fraction (undersize) from the screens is returned... 

The distinguishing features on which this classification is based are the spatial properties of the artifacts. Flares that are well localized within the image and manifest themselves in characteristic shapes are called ghosts or ghosting. Needless to say, effects like these can cause far more critical misinterpretations of the scene than a spurious illuminance that is more or less evenly distributed over the image. The different flare types wiU now be discussed in detail. 

In all of the process operations except venting and flaring, exposure is related to worker activity, and to some extent is dependent on worker behavior and the work practices appHed. The distinction between those exposures that are impacted by worker behavior and those that, barring the use of respirators, are not is important. The types of control methods to be appHed and the methods of exposure measurement to be used are influenced by this difference. 

Once an undesirable material is created, the most widely used approach to exhaust emission control is the appHcation of add-on control devices (6). Eor organic vapors, these devices can be one of two types, combustion or capture. AppHcable combustion devices include thermal iaciaerators (qv), ie, rotary kilns, Hquid injection combusters, fixed hearths, and uidi2ed-bed combustors catalytic oxidi2ation devices flares or boilers/process heaters. Primary appHcable capture devices include condensers, adsorbers, and absorbers, although such techniques as precipitation and membrane filtration ate finding increased appHcation. A comparison of the primary control alternatives is shown in Table 1 (see also Absorption Adsorption Membrane technology). 

Flow Nozzles A simple form of flow nozzle is shown in Fig. 10-17. It consists essentially of a short cylinder with a flared approach section. The approach cross section is preferably elliptical in shape but may be conical. Recommended contours for long-radius flow nozzles are given in ASME PTC, op. cit., p. 13. In general, the length of the straight portion of the throat is about one-h f throat diameter, the upstream pressure tap is located about one pipe diameter from the nozzle inlet face, and the downstream pressure tap about one-half pipe diameter from the inlet face. For subsonic flow, the pressures at points 2 and 3 will be practically identical. If a conical inlet is preferred, the inlet and throat geometry specified for a Herschel-type venturi meter can be used, omitting the expansion section. 

Combustion-Control Equipment Combustion-control equipment can be divided into three types (1) flares, (2) thermal incinerators, (3) catalytic incinerators. 

For the tandem arrangement gas seal, a primary seal vent must be pro vided to vent the leakage across the process side seal. This vent ma> lie to flare or other suitable gas disposal point. The back pressure under nor mal conditions should be kept to a low value. A small amount of back pressure is recommended to keep a positive differential across the see ondaiy seal. Leakage measurement may be provided in the vent line to provide health monitoring of the primary seal. Unfortunately, the rotameter, which would be the obvious choice, should not be used because of its lack o reliability. If an orifice or needle valve is used to set the back pressure to the seal vent, pressure upstream of the restriction can be measured for a relative flow measurement. This type of reading does provide trend data that may be used to judge the seal s performance. 

When running SCREEN for a point source, or for flare releases and area sources discussed below, you are first asked to provide a one line title (up to 79 characters) that will appear on the output file. You will then be asked to identify the source type, and should enter P or p for a point source (the model will identify either upper or lowercase letters and will repeat the prompt until a valid response is given). For a point source, you will be asked to provide the following inputs ... 

By answering F or f to the question on source type the user selects the flare release option. This option is similar to the point source described above except for the inputs needed to calculate plume rise. The inputs for flare releases are described below. 

SIMPLE TERRAIN INPUTS SOURCE TYPE EMISSION RATE (G/S) FLARE STACK HEIGHT (H) TOT HEAT RLS (CAL/S) RECEPTOR HEIGHT (M) UR6AN/RURAL OPTION EFF RELEASE HEIGHT (H) BUILDING HEIGHT (M)... 

Flares ideally bum waste gas completely and smokelessly. Two types of flares are normally employed. The first is called the open flare, whereas the second is called the enclosed flare. The major components of a flare consist of the burner, stack. 

Elevated Flares See Flares for a general definition. The elevated flare, by the use of steam injection and effective tip design, operates as a smokeless combustion device. Flaring generally is of low luminosity up to about 20 % of maximum flaring load. Steam injection tends to introduce a source of noise to the operation, and a compromise between smoke elimination and noise is usually necessary. When adequately elevated (by means of a stack) this type of flare displays the best dispersion characteristics for malodorous and toxic combustion products. Visual and noise pollution often creates nuisance problems. Capital and operating costs tend to be high, and an appreciable plant area can be rendered unavailable for plant operations and equipment because of excessive radiant heat. 

Conventional Flare System - The majority of pressure relief valve discharges which must be routed to a closed system are manifolded into a conventional blowdown drum and flare system. The blowdown drum serves to separate liquid and vapor so that the vapor portion can be safely flared, and the separated liquid is pumped to appropriate disposal facilities. The blowdown drum may be of the condensible or noncondensible type, according to the characteristics of the streams entering the system. Selection criteria, as well as the design basis for each type of blowdown drum, are detailed later in this volume. The design of flares, including seal drums and other means of flashback protection, is described later. 

Thermal Expansion in Flare Header - Sliding-type expansion joints may be used in flare headers as an alternative to piping expansion loops, if required to achieve a reduction in pressure drop or where expansion bends may result in liquid surging, subject to the following conditions ... 

Potential vibration problems of this type should be considered early in the design stage of the flare header system. The following screening criteria have been developed to assist the designer in recognizing services with potential vibration problems requiring further detail evaluation ... 

Lx)cate the blowdown drum (when the non-condensible type is used) at a minimum permissible spacing from the flare, to minimize condensation in the flare header. 

Three types of flare systems are commonly used the elevated flare, the ground flare, and the burning-pit flare. Although the three basic designs differ considerably in required capital and operating costs, selection is based primarily on pollution/public relations considerations such as smoke, luminosity, air pollution, noise and spacing factors. Table 1 summarizes the advantages and... 

Three types of stack for elevated flares are used ... 

Self-Supporting Stack - This type of unit is designed so that the flare riser pipe has no lateral strucmral support. For short flares, this type is the least expensive to erect and maintain. 

Various designs of ground flare are available. The type which has been used... 

Other designs of ground flares suitable for refinery application are available. In some of these cases, noise is appreciable, in comparison with the multijet type, but their compact size, low space requirement, simplicity, and hence low cost, may give an overall advantage. 

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