Process and apparatus for conditioning of combustion flue gases with ammonia from hydrolyzed urea
AssigneeEnvironmental Elements Corp.
InventorsRobert T. Glesmann, Joseph J. Titus, Hamilton G. Walker JR.
Life of this patent
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Abstract
An improved process and apparatus for combustion flue gas conditioning in which ammonia is produced in situ from the hydrolysis of urea and injected into a stream of combustion flue gases, wherein key components of the process and apparatus are made to function independently of other components to prevent the shut-down of the entire apparatus in the case of a single component break-down.
Claims33
A process for conditioning of combustion flue gases with ammonia from hydrolyzed urea comprising the steps of:
- a) adding solid urea to a hopper;
- b) transferring the urea from the hopper to a dissolver;
- c) dissolving the urea in water in the dissolver, forming a urea solution;
- d) transferring the urea solution to a solution storage tank;
- e) pumping the urea solution from the solution storage tank to a pre-heater;
- f) pre-heating said urea solution;
- g) transferring the pre-heated urea solution to at least one hydrolyzer;
- h) hydrolyzing the urea in the urea solution, forming a hydrolyzed solution comprising ammonia, carbon dioxide and residual water;
- i) stripping said ammonia and carbon dioxide from said hydrolyzed solution by contacting said hydrolyzed solution with steam;
- j) injecting said ammonia and carbon dioxide in a gaseous form through a gas outlet in at least one hydrolyzer into said stream of said combustion flue gas;
- k) transferring the residual water from at least one hydrolyzer through a heat exchanger to a holding tank;
- and
- l) recycling residual water from the holding tank to the dissolver.
The process according to 1, further comprising transferring excess heat from the residual water leaving at least one hydrolyzer to the pre-heater.
The process according to 1, further comprising controlling the temperature of the residual water in the holding tank.
An apparatus for conditioning of combustion flue gases with ammonia from hydrolyzed urea comprising:
- a) a hopper including an inlet, a main body with a shaped bottom section, and an outlet;
- b) a dissolver including a urea inlet, a water inlet, a residual water inlet, and an outlet;
- c) a solution storage tank including an inlet and an outlet;
- d) a line with a pump connecting the solution storage tank to a pre-heater
- e) a pre-heater;
- f) at least one hydrolyzer including a urea solution inlet, a steam inlet, at least one gas outlet, and a residual water outlet;
- and
- g) a holding tank including an inlet and an outlet.
The apparatus of claim 25, wherein the heating element can maintain the temperature of the contents of the holding tank between about 80° F. to about 200° F.
In a process for conditioning combustion flue gas by ammonia gas produced in situ where the process includes dissolving urea in water, forming a urea solution, pre-heating urea solution in a pre-heater, and then heating and pressuring the solution in a hydrolyzer, where the urea solution is hydrolyzed forming carbon dioxide and ammonia in solution, stripping the ammonia and carbon dioxide from the solution with steam introduced into the hydrolyzer to form gaseous ammonia and carbon dioxide and leaving residual water in the hydrolyzer, injecting the ammonia and carbon dioxide into a stream of combustion flue gases, and sending the residual water from the hydrolyzer to a separator and recycling the residual water, the improvement comprising:
- a) storing a surplus urea solution in a solution storage tank;
- b) connecting more than one hydrolyzers to a common output line, thereby eliminating the need for a separator;
- c) directing the residual water to a holding tank;
- and
- d) recycling the residual water from the holding tank to the dissolver.
Dependencies are inferred from the claim text.