Solar Boiler System

Abstract

It is an object of the present invention to provide a solar boiler system that can suppress the installation cost for a solar heat collector and significantly improve gross thermal efficiency while minimizing a rise in air temperature resulting from the collected solar heat. The solar boiler system of the present invention includes a boiler for burning fossil fuel; a primary air system for pneumatically transporting pulverized fossil fuel to a burner attached to the boiler; a secondary air system for supplying preheated air for combustion to the boiler; and a secondary air superheater provided at the secondary air system, the secondary air superheater further superheating the preheated air for combustion with solar thermal energy.

1 . A solar boiler system comprising:
 a boiler for burning fossil fuel;   a primary air system for pneumatically transporting pulverized fossil fuel to a burner attached to the boiler;   a secondary air system for supplying preheated air for combustion to the boiler; and   a secondary air superheater provided at the secondary air system, the secondary air superheater further superheating the preheated air for combustion with solar thermal energy.   
     
     
         2 . A solar boiler system comprising:
 a boiler for burning fossil fuel;   a primary air draft fan for generating air for transportation which allows pulverized fossil fuel to be pneumatically transported to the boiler;   a primary air heater for preheating the air for transportation sent from the primary air draft fan;   a forced draft fan for generating air for combustion of the boiler;   a secondary air heater for preheating the air for combustion sent from the forced draft fan; and   a secondary air superheater for superheating the air for combustion at an outlet of the secondary air heater by using solar thermal energy as a heat source.   
     
     
         3 . The thermal boiler system according to  claim 2 , further comprising:
 a plurality of solar light collecting mirrors for collecting solar light;   a heat exchanger for subjecting a heat medium for heat storage to heat exchange with a heat medium, which is heated with the solar thermal energy collected by the solar light collecting mirrors;   a low-temperature tank for storing a low-temperature heat medium for heat storage used for heat exchange in the heat exchanger;   a high-temperature tank for storing a high-temperature heat medium for heat storage heated in the heat exchanger; and   a changeover valve for switching to allow the heat medium for heat storage to flow to both the low-temperature tank and the high-temperature tank.   
     
     
         4 . A method of retrofitting an existing boiler system, the existing boiler system including:
 a boiler for burning fossil fuel;   a primary air draft fan for generating air for transportation which allows pulverized fossil fuel to be pneumatically transported to the boiler;   a primary air heater for preheating the air for transportation sent from the primary air draft fan;   a forced draft fan for generating air for combustion of the boiler; and   a secondary air heater for preheating the air for combustion sent from the forced draft fan;   the method comprising the step of additionally installing:   a solar heat recovery apparatus for collecting solar thermal energy; and   a secondary air superheater for further superheating the air for combustion at an outlet of the secondary air heater by using solar thermal energy collected by the solar heat recovery apparatus as a heat source.