Chapter 17, Problem 20P

Consider a 400-MW, 32 percent efficient coal-fired power plant that uses cooling water withdrawn from a nearby river (with an upstream flow of 10-m3/s and temperature 20 °C) to take care of waste heat. The heat content of the coal is 8,000 Btu/lb, the carbon content is 60% by mass, and the sulfur content is 2% by mass. How much electricity (in kWh/yr) would the plant produce each year? How many pounds per hour of coal would need to be burned at the plant? Estimate the annual carbon emissions from the plant (in metric tons C/year). If the cooling water is only allowed to rise in temperature by 10 °C, what flow rate (in m3/s) from the stream would be required?  What would be the river temperature if all the waste heat was transferred to the river water assuming no heat losses during transfer?  Estimate the hourly SO2 emissions (in kg/h) from the plant assuming that all the sulfur is oxidized to SO2 during combustion.

Problem 10 A homeowner is trying to decide between a high-efficiency natural gas furnace with an efficiency of 95 percent and a ground-source heat pump with a COP of 3.3. The unit costs of electricity and natural gas are $0.112/kWh and $1.44/therm (1 therm = 105, 500 kJ). Determine which system will have a lower energy cost.

A 1000 MW coal fired power plant (30% efficiency). The coal is 75% carbon and has a heat content of 10, 000 BTU/lb. What is the carbon emission (ton carbon per year)?A 1000 MW natural gas plant (45% efficiency). The gas is CH4 with a heat content 800 BTU/mol. What is the carbon emission (ton carbon per year)?Calculate carbon emission reduction if the above natural gas plant is used to replace the coal fired plant.(Here ton is metric ton, 1 ton=2,200 lb)