Supplementary heat supplied

For (b), Cerri assumed that the supplementary heat supplied was sufficient to give a maximum temperature equal to the assumed maximum steam entry temperature T. In general, it was shown that for the higher values of now used in CCGT plants there was little or no benefit on overall efficiency associated with supplementary heating. 

Consider a combined power plant made up of two cyclic plants (H, L) in series (Fig. 7.1). In this ideal plant, heat that is rejected from the higher (topping) plant, of thermal efficiency tjh, is used to supply the lower (bottoming) plant, of thermal efficiency tjl, with no intermediate heat loss and supplementary heating. 

For a plant with a fired heat boiler, as in Fig. 9.2b, both the work output Wcg ind the main heat supply = F are assumed to be unaltered at 1.0 and 4.0, respectively, but supplementary fuel energy is supplied to the WHB, Fj = 1.5F = 6.0. The useful heat supplied is then assumed to increase to 7.2 and the non-u.seful heat rejected to be 1.8. Thus the parameter A changes to 7.2. 

This total heat load is given as 22.6 x 10 kWh per annum. Supplementary heat is therefore necessary to provide the additional (22.6 — 13) = 9.6 x 10 kWh per annum. For security of supply, 4 MW boilers capable of giving full independent supply provided this. 

The pour point is the lowest temperature at which the bitumen will flow. The pour point for tar sand bitumen can exceed the natural temperature of tar sand deposits. It is important to consider because for efficient production a thermal extraction process to increase the reservoir temperature to beyond the pour point temperature must supply supplementary heat energy. Elements related to pour point are depth, bitumen viscosity, original reservoir temperature, and atomic hydrogen/carbon ratio. 

The system concept has only two input streams for air and propane and one common output stream. Air is used as oxygen carrier for the cathode and the burner and serves in addition as cooling medium for the stack. As propellant gas for the ejector the already pressurised propane fuel is used. To reduce heat up time during system start up an additional propane supply to the burner is integrated, enabling supplementary energy supply. Nevertheless, at steady state operation propane is supplied only to the ejector. The only output stream is the exhaust gas from the burner. Figure 1 shows the flowchart. 

The above simple analysis has to be modified for a supplementary fired CHP plant such as that shown in Fig. 9.3c, meeting a unit electrical demand and an increased heat load A. The reference. system fuel energy supplied is now... 

Electrical power output Heat output (normal load) (with supplementary firing) Gas fuel energy supply Thermal efficiency... 

Figure 5.5a depicts a combined plant in which a closed Brayton helium nuclear plant releases heat to a recovery steam generator, which supplies heat to a Rankine steam plant. The generator is provided with a gas burner for supplementary additional heat when the demand of steam power is high. The Rankine plant is a regenerative cycle. 

The heat released reaches 3000°C to 3500°C. As this temperature is well above the melting points of most metals, the torch is used for welding. For cutting steel slabs, the flame is directed to the steel slabs. A supplementary supply of oxygen is added to the flame by another jet which bums the steel slabs sending out a shower of sparks. This torch can be used under water also. 

Gas and slag (molten ash) leave the reactor at 2500°C. The gas contains CO, H2, CO2, and H20. (a) Feeding oxygen to the reactor lowers the yield of synthesis gas, but no gasifier ever operates without supplementary oxygen. Why does the oxygen lower the yield Why it is nevertheless always supplied. Hint All the necessary information is contained in the first two stoichiometric equations and associated heats of reaction shown above.)... 

The heat exchanger system is sized to maintain the outlet temperature such that the outlet water fi-om the tube at full dissipation does not exceed 70 C. Supplementary coolant courses may be connected in parallel or series with the main supply as long as the maximum outlet temperature is not exceeded. 

Where other potential metallic conductors exist near to electrical conductors in a building, they must be connected to the main earth terminal to ensure equipo-tential bonding of all conductors to earth. This applies to gas, water and central heating pipes and other devices such as lightning protection systems. Supplementary bonding is required in bathrooms and kitchens where, for example, metal sinks and other metallic equipment surfaces are present. This involves the connection of a conductor from the sink to a water supply pipe which has been earthed by equipotential bonding. There have been several fatalities due to electric shocks from live service pipes or kitchen sinks. 

Calculate the amount of supplementary fuel that must be added to attain the desired combustion chamber temperature. In most cases the oxygen content of the feed gas will be high enough (over about 16%) to provide an adequate supply of oxygen for combustion of botli fuel and impurities, and the concentration of combustible impurities will be so low that their heat of combustion can be neglected. When precise calculations are required, or when the feed gas contains a solvent concentration over 2-3% of the LEL, it is necessary to take the heat of combustion of the gas impurities into account. The amount of fuel required can be estimated using a simple heat balance around the combustion chamber. The calculated amount of fuel should be increased as required to account for 5-10% heat losses from the incinerator. If the heat balance indicates that excess heat is available from combustion of the VOCs. a lower efficiency heat recovery unit can be used or. with a... 

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