System for preheating glass melting furnace batch materials
A system for preheating batch materials in a glass melting furnace includes a preheater having an outlet through which fluid is exhausted and an inlet that receives fluids exhausted from the furnace and recirculated from the preheater outlet. In one embodiment, a cyclonic separator has an inlet in communication with the preheater outlet and an outlet in fluid communication with a fan. A controller controls the speed of the fan responsive to a drop in pressure between the separator inlet and outlet and a temperature at the separator outlet. In other embodiments, controllers control valves that (i) control the amount of fluids exhausted from the preheater that are delivered to a flue and recirculated to the preheater or (ii) control the amount of fluids diverted to charger for the furnace, in response to temperatures in a duct coupled to the preheater inlet.
1. A system for preheating batch materials prior to delivery to a glass melting furnace, comprising:
a preheater configured to receive unheated batch materials and to deliver heated batch materials, the preheater including a primary outlet configured to exhaust fluid from the preheater and a primary inlet configured to receive exhaust fluids from the glass melting furnace and exhaust fluids recirculated from the primary outlet of the preheater;
a first valve configured to control a first amount of exhaust fluid from the preheater delivered to a flue for combination with exhaust fluid from the glass melting furnace;
a second valve configured to control a second amount of exhaust fluid from the preheater recirculated to the inlet of the preheater;
a first temperature sensor configured to generate a first temperature signal indicative of a first temperature of fluids within a first duct coupled to the inlet of the preheater; and,
an inlet temperature controller configured to control the first valve and the second valve responsive to the first temperature.
2. The system of claim 1 , further comprising a second temperature sensor configured to generate a second temperature signal indicative of a second temperature of the fluids within the first duct coupled to the inlet of the preheater at a location in the duct upstream of where the first temperature is obtained and wherein the inlet temperature controller is configured to control the first valve and the second valve responsive to one of the first and second temperatures.
3. The system of claim 2 wherein the inlet temperature controller is configured to control the first valve and the second valve responsive to the second temperature if the second temperature meets a predetermined condition.
4. The system of claim 3 wherein the predetermined condition comprises whether the second temperature exceeds the first temperature by more than a predetermined amount.
5. The system of claim 2 wherein the inlet temperature controller controls the first and second valves responsive to the one of the first or second temperatures in accordance with a predefined split range control profile.
6. The system of claim 1 wherein the inlet temperature controller controls the first and second valves responsive to the first temperature in accordance with a predefined split range control profile.
7. The system of claim 1 wherein the inlet temperature controller is configured to maintain both of the first and second valves at least partially open at all times.
8. The system of claim 1 , further comprising a pressure sensor configured to generate a pressure signal indicative of a pressure in a second duct conveying exhaust fluid from the preheater to the flue and wherein the inlet temperature controller is further configured, in controlling the first valve and the second valve, to adjust a minimum opening of each of the first and second valves responsive to the pressure signal.
9. The system of claim 8 wherein the inlet temperature controller is further configured, in adjusting the minimum opening of each of the first and second valves, to:
compare the pressure in the second duct to a predetermined threshold pressure; and,
increase the minimum opening of each of the first and second valves if the pressure in the second duct meets a predetermined condition relative to the predetermined threshold pressure.