Method and apparatus for safely controlling explosions in black liquor recovery boilers

An apparatus for preventing explosive reactions in furnaces caused by the addition of water to a molten smelt, wherein said furnace includes a black liquor inlet flow pipe and spray nozzle connected to said flow pipe, comprising:

• (a) means for sensing the apparent presence of water in said smelt, including radiation detection means for selectively detecting the presence and absence of burning proximate said nozzles in said furnace, and means for detecting the flow of black liquor in said flow pipe, and means connected to both said flow detecting means and said radiation detection means, for generating a warning signal when black liquor flow is detected and no radiation is detected from the proximity of said spray nozzle;
• (b) an elongated barrel having dispensing nozzles proximate one end, said barrel nozzles being movable from a first position outside said furnace to a second position inside said furnace;
• (c) means for dispensing an absorption agent under pressure through said barrel and said dispensing nozzles;
• (d) control means coupled to said sensing means to receive said warning signal, for generating a command signal upon detection of said warning signal from said means for sensing;
• and
• (e) means for coupling said command signal to said barrel to cause movement thereof into said furnace and means for coupling said command signal to actuate said means for dispensing an absorption agent.

An apparatus for preventing an explosive reaction in a black liquor furnace having a black liquor inlet flow pipe and spray nozzles connected to the flow pipe and from water leakage in smelt therein from steam and water pipes therein, comprising:

• (a) a radiation detection means connected to said furnace for selectively detecting the presence and absence of burning proximate said nozzles in said furnace;
• (b) means for detecting the flow of black liquor in said flow pipe;
• (c) means connected to both said flow detecting means and said radiation detection means, for generating a first signal when black liquor flow is detected and no radiation is detected from the proximity of said nozzles;
• (d) pressure sensitive means for detecting pressure drops in said steam and water pipes and generating a second signal in response thereto;
• (e) storage means positioned adjacent said furnace and having a membrane-sealed end projecting toward said smelt through an opening in said furnace, said storage means housing silica gel granules under pressure, for physical and chemical conversion of said smelt;
• (f) an explosive device attached to said membrane, said explosive device being actuable by said first or second signal;
• and
• (g) means for coupling said first and second signal to said explosive device.

An apparatus for preventing explosive reactions in furnaces cause by the addition of water to a molten smelt, wherein the furnaces include a black liquor inlet flow pipe and spray nozzles connected to said flow pipe, comprising:

• (a) means for storing an absorption agent adjacent said furnace, said means having further means for propelling said absorption agent into said smelt upon command;
• including at least one extensible nozzle movable from a first position outside said furnace to a second position inside said furnace;
• and
• (b) manual actuation control means for generating said command, and including means for coupling said command to said means for storing;
• and
• (c) a plurality of granules of silica gel in said means for storing and serving as said absorption agent;
• and
• (d) radiation detection means connected to said furnace for selectively detecting the presence and absence of burning proximate said nozzles in said furnace;
• and
• (e) means for detecting the flow of black liquor in said flow pipe;
• and
• (f) means connected to both said flow detection means and said radiation detection means, for generating said command when black liquor flow is detected and no radiation is detected from the proximity of said spray nozzles, and including means for coupling said command to said means for storing.

A method of stabilizing a mixture including water and molten smelt in a black liquor furnace and boiler, wherein black liquor flows into said furnace through an inlet flow pipe and is sprayed through nozzles connected to said flow pipe in said furnace, comprising the steps of

• (a) monitoring the flow of black liquor through said inlet flow pipe to said furnace;
• and
• (b) detecting the radiation proximate said nozzles for determining the presence and absence of combustion proximate said nozzles;
• and
• (c) generating a signal when said combustion ceases and said black liquor flow continues into said furnace;
• and
• (d) immediately propelling an absorption agent comprising silica gel for absorbing water in said molten smelt;
• and
• (e) substantially saturating said smelt with said absorption agent.