The following observations were recorded during a boiler trial of 1 hr duration. 700 kg of coal of calorific value 30,000 kJ/kg is used to produce 5,250 kg of steam at a pressure of 12 bar. Dryness fraction of steam is 94%. Temperature of steam leaving the superheater is 250°C and temperature of hot well is 45°C. Calculate: (i) Equivalent evaporation. (ii) Thermal efficiency of boiler.

The following observations were recorded during a boiler trial of 1 hr duration. 700 kg of coal of calorific value 30,000 kJ/kg is used to produce 5,250 kg of steam at a pressure of 12 bar. Dryness fraction of steam is 94%. Temperature of steam leaving the superheater is 250°C and temperature of hot well is 45°C. Calculate: (i) Equivalent evaporation. (ii) Thermal efficiency of boiler.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter9: Heat Transfer With Phase Change

Section: Chapter Questions

Problem 9.28P

See similar textbooks

Similar questions

Calculate the amount of heat required (in kJ) to raise the temperature of 23.4 g of ice at -11°C to steam at 135°C. ΔHvap = 40.67 kJ/mol, ΔHfus = 6.008 kJ/mol, Cice = 2.092 J/g°C, Cwater = 4.184 J/g°C, Csteam = 1.841 J/g°C, Melting point = 0.00°C, Boiling Point = 100.0°C
b) The high pressure units on a steam plant operate at 10bar (gauge), and the condensate is sub-cooled by 9.5K. If the mass flow rate of condensate is 10 kg/s, use the provided steam tables to determine how much saturated steam at 1.5 bar this condensate could produce. Note it is sufficiently accurate for high pressure condensate, as in this question, to assume that the specific enthalpy is the same as for the saturated liquid at the same temperature.
Complete solution; Steam is generated at 4.1 Mpa and 440 OC and condensation occurs at 0.105 Mpa. For a Rankine cycle operating between this limits, determine (a) heat supplied, KJ/kg, (b) heat rejection, KJ/kg, (c) the Work net, KJ/kg, (d) thermal efficiency, and (e) what mass flow rate is required for a net output of 30,000 KW? Kg/s
if 2460 kj/kg of heat is added to water at 0 degrees celcius to produce wet steam at 1500 kpa , calculate th dryness fraction .
Air at 40˚C and 55% RH is heated using a heat exchanger to reach 90˚C. using a psychrometric chart, specify a. The amount of heat added per 1 m3 of initial air = (Kj)b. Condensation temperature = (˚C)
What is the dryness fraction at state 6 to 3 d.p.
Water at atmospheric pressure enters a 1.2 [cm] ID, 2.4 [m] long electrically heated vertical pipe at a subcooling of 15 [℃]. the inlet velocity of water is 1.1 [m/s], and the heated power is 8 [kW]. Using the homogenous equilibrium model (HEM) of the two-phase flow, determine the following parameters. The length of the boiling section of the channel The liquid and the vapor mass flow rates at the exit of the channel The liquid and the vapor volumetric flow rates at the exit of the channel The exit quality The exit void fraction Plot the axial distributions of the flow quality and the void fraction along the channel How will your answer to parts (e) change if the two-phase flow in the boiling section experienced phasic slip with a constant slip ratio, S = 1.6?
Hot air at 40 ° C and RH 65% is heated using a heat exchanger to reach 90 ° C. Using a psychrometric chart, determine:a) the amount of heat added per 2 m³ of initial air = ... (kJ) b) condensation temperature = ... (° C)
An evaporator is concentrating F kg/hr at 311K of a 20 wt % solution of NaOH to 50%. The saturated steam used for heating is at 399.3 K. The pressure in the vapor space of the evaporator is 13.3 kPa abs. The overall coefficient is 1420 W/. K and the area is 86.4 square meters. Calculate the feed rate F of the evaporator.
From an open water surface with air temperature 22°C, relative humidity is 40% and wind speed is 3 m/s, all measured at height 2 m above the water surface. Assume a roughness height of 0.03 cm. The net radiation is 200 W/m^2. Cp = 1005 J/kg-K A. Calculate the latent heat of vaporization (J/kg) B. Calculate the evaporation using Energy Balance Method (mm/day) C. Calculate the saturation deficit of the vapor pressure (Pa) D. Calculate the evaporation using Priestley-Taylor Method (mm/day)
Steam is delivered to turbine at 5.4 MPa and 600 degree C. Before condensation at 31 degree C, steam is extracted for feed water heating at 0.6 MPa. The turbine exhaust is 60 degree C. the required values of some state point properties are tabulated below. 8. Calculate the mass fraction (m) of bled steam at extraction point.
Combustion in a diesel engine is assumed to begin at TDC and proceed at constant pressure. The air/fuel ratio is 27/1, the calorific value of fuel is 43 MJ/kg, and the specific heat of combustion products is given by: Cy = 0.71 + 20x10-5 T where Tis the combustion products temperature in K unit. The gas constant for these products is taken to be 0.287 kJ/kg K. If the compression ratio is 15/1, and the temperature at the end of compression is 870 K, find at what percentage of the stroke the combustion is completed. 2312w