Method for regenerating filter and apparatus thereof

• US 20080127824A1
• Filed: 11/30/2006
• Published: 06/05/2008
• Est. Priority Date: 11/30/2006
• Status: Active Grant

• Current Assignee: Mitsubishi Power Limited (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Shinada, Osamu, Kitagawa, Yuichiro, Takahira, Ryouji, Koyama, Yoshinori, Imagama, Kazunari, Takase, Soken
• Granted Patent: US 7,896,956 B2
• Time in Patent Office: Days
• US Class Current: 95/280
• CPC Class Codes: B01D 46/0093 against fire or explosion
• CPC Class Codes: B01D 46/2407 Filter candles
• CPC Class Codes: B01D 46/80 Chemical processes for the removal of the retained particles, e.g. by burning

Abstract

A filter regeneration apparatus of a coal gasification system having a filter for capturing char (unburned matter) present in exhaust gas at an exhaust gas passage communicating with exhaust gas source including a coal gasification furnace, fills the filter container with inactive gas having oxygen concentration of less than 5 vol. % and heat the filter to a target temperature of 400 to 450° C. and feed ashing gas having oxygen concentration of 5 to 15 vol. %, thereby ashing char in the filter. This method and apparatus achieve ashing of char in a safe manner and shortens the time of regenerating the filter by controlling the oxygen concentration in the ashing gas and the filter temperature constantly to reach preset target values.

Claims

1. A method for regenerating a filter in a coal gasification system for capturing char (unburned matter) present in exhaust gas at an exhaust gas passage communicating with exhaust gas source including a coal gasification furnace, the regeneration method comprising the steps of

filling the filter with inactive gas having oxygen concentration of less than 5 vol. %;

heating the filter so that the filter temperature is maintained at 400 to 450°

C.; and

feeding into the filter the ashing gas which is adjusted to have oxygen concentration of 5 to 15 vol. %, thereby ashing (oxidizing) the char in the filter.

2. A method for regenerating a filter according to claim 1, comprising the steps of;

measuring oxygen concentration in the ashing gas at the filter outlet; and

controlling at least one of flow and oxygen concentration in the ashing gas so that the oxygen concentration measured at the filter outlet reaches a preset target concentration.

3. A method for regenerating a filter according to claim 1, comprising the steps of;

cutting off the ashing gas being supplied to the filter and finishing the regeneration of the filter when at least one of the following cases is detected;

a) differential pressure in the filter between the inlet side and outlet side reaches a target differential pressure;

b) oxygen concentration at the filter outlet reaches a target oxygen concentration;

or

c) CO2 concentration at the filter outlet reaches a target CO2 concentration.

4. A filter regeneration apparatus of a coal gasification system having a filter for capturing char (unburned matter) present in exhaust gas at an exhaust gas passage communicating with exhaust gas source including a coal gasification furnace;

the filter regeneration apparatus comprising;

filling means for filling the filter with inactive gas having oxygen concentration of less than 5 vol. %;

heating means for heating the filter so that the filter temperature is maintained at 400 to 450°

C.;

feeding means for feeding into the filter the ashing gas which is adjusted to have oxygen concentration of 5 to 15 vol. %; and

setting means for setting cutting-off timing of the ashing gas supply in synchronization with completion of char ashing (oxidizing) in the filter

8. A filter regeneration apparatus according to claim 4, wherein the filter regeneration apparatus is integrated in an coal gasification combined power-generating unit.

5. A filter regeneration apparatus of a coal gasification system having a filter for capturing char (unburned matter) present in exhaust gas at an exhaust gas passage communicating with exhaust gas source including a coal gasification furnace;

the filter regeneration apparatus comprising;

heating means for heating the filter;

an oximeter for measuring oxygen concentration at the inlet of ashing gas;

ashing gas oxygen adjusting means for adjusting oxygen concentration in ashing gas;

temperature measuring means for measuring a temperature of the filter; and

a controller for controlling thermal dose of the heating means to heat the filter to 400 to 450°

C. based on inputted filter temperature which is measured by the temperature measuring means and controlling the adjusting means so that oxygen concentration in the ashing gas reaches a target oxygen concentration of 5 to 15 vol. % based on the measured oxygen concentration.

6. A filter regeneration apparatus according to claim 5, further comprising;

another oximeter for measuring oxygen concentration at the filter outlet; and

ashing gas flow adjusting means for adjusting flow of the ashing gas,

wherein the controller controls at least one of the ashing gas flow adjusting means and the ashing gas oxygen adjusting means so that inputted oxygen concentration measured at the filter inlet reaches a target oxygen concentration.

7. A filter regeneration apparatus according to claim 5, further comprising at least one of:

differential pressure detecting means for detecting differential pressure between the filter inlet and filter outlet;

another oximeter for measuring oxygen concentration at the filter outlet; and

CO2 meter for measuring CO2 concentration at the filter outlet,

wherein the controller closes the ashing gas flow adjusting means to cut off the ashing gas being supplied to the filter when at least one of the following cases is detected;

d) the detected differential pressure inputted from the differential pressure detecting means reaches a preset target differential pressure;

e) the measured oxygen concentration inputted from the another oximeter reaches a preset target oxygen concentration;

or

f) the measured CO2 concentration inputted from CO2 meter reaches a preset target CO2 concentration.