What is smelt in a recovery boiler?
What is smelt in a recovery boiler?
The black liquor recovery boiler is designed to burn the volatile organic material in black liquor for its heating value and to allow the inorganic chemicals to collect on the floor of the boiler in a molten bed referred to as smelt. The molten smelt that collects at the bottom of the boiler is extremely high in soda.
What is the purpose of recovery boiler?
The purpose of the recovery boiler is to recover the inorganic chemicals as smelt (sodium carbonate and sodium sulfide), burn the organic chemicals so they are not discharged from the mill as pollutants, and recover the heat of combustion in the form of steam.
What is black liquor in paper industry?
In industrial chemistry, black liquor is the waste product from the kraft process when digesting pulpwood into paper pulp removing lignin, hemicelluloses and other extractives from the wood to free the cellulose fibers.
How much does a recovery boiler cost?
A professor of chemical engineering at the University of Maine who specializes in pulp and paper manufacturing processes and biorefinery, Van Heiningen said that new recovery boilers can cost as much as $100 million — a steep investment given the U.S. paper manufacturing industry’s decades-long downturn.
What is a boiler economizer?
A boiler economizer or flue gas heat recovery unit is a heat exchanger that is installed on the stack of a boiler. It is designed to recover heat that would otherwise be wasted. Economizers can be installed during a new boiler installation or retrofit on an existing system.
Where is the evaporator drum located in the Loeffler boiler?
The evaporating drum is placed at the bottom of the boiler. It has a mixing nozzle. In this, the feed water is transformed into saturated steam with the help of superheated steam in the superheater.
What is power boiler?
Power boiler means a boiler in which steam or other vapor is generated at a pressure of more than 15 psig for use external to itself or a boiler in which water is heated and intended for operation at pressures in excess of 160 psig and/or temperatures in excess of 250 degrees F by the direct application of energy from …
Is black liquor caustic?
Due to the caustic nature of the solution it is expected that there would be toxic effects (e.g. edema) to the respiratory system if mists or vapors are inhaled and toxic effects for skin and eye exposures, especially at elevated temperatures.
What is the pH of black liquor?
pH 13 to 14
The pH of black liquor is rather high (pH 13 to 14), and the phenolic groups on lignin molecules are ionized, making the lignin soluble in a water solution.
What is a power boiler?
Power boilers take the chemical energy stored in fuel, convert it to heat energy in the combustion process, and transfer that heat energy to water to produce steam. The transfer of energy from combustion gases to the water and steam is called heat transfer.
Where is the economizer located in a boiler?
They are heat exchanger coils‚ usually finned‚ that are located in the flue gas ducting at the exit of the boiler. Typically‚ a non-condensing economizer will raise the overall efficiency by 2 % to 4 % .
Where can I find a salt cake boiler?
Commonly found in pulp and paper mills around the country, these recovery boilers are vital to the pulp producing process. The salt cake handling systems is the materials handling system on the boiler and precipitator that recovers the solid inorganic materials produced from the black liquor burning process.
How are chemical recovery boilers used in pulp and paper plants?
Chemical Recovery Boilers in Pulp and Paper Plants – Part 1. In a pulp and paper plant the sodium salts used for extracting the lignin from wood during cooking have to be recovered to make the process viable. A cooking liquor recovery cycle retrieves white liquor for the cook from the black liquor spent chemicals obtained from the pulp wash.
Which is the industry leader in black liquor recovery boiler?
ProcessBarron is the industry leader in Salt Cake Handling Systems for Black Liquor Recovery Boiler and Precipitator Black Salt Cake Handling Systems. Commonly found in pulp and paper mills around the country, these recovery boilers are vital to the pulp producing process.
How are sodium salts recovered in pulp and paper plants?
In a pulp and paper plant the sodium salts used for extracting the lignin from wood during cooking have to be recovered to make the process viable. A cooking liquor recovery cycle retrieves white liquor for the cook from the black liquor spent chemicals obtained from the pulp wash.
