Recovery boiler - Revision history

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2024-12-10T00:47:38Z

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← Older revision		Revision as of 00:47, 10 December 2024
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	[[File:SantaFeRecoveryBoiler.JPG\|thumb]] ~~[[File:Svartlut 76.jpg~~\|~~thumb]] [[File:EarlyTomlinsonRB.gif~~\|~~thumb]] [[File:Black~~ liquor ~~nozzle.JPG~~\|~~thumb]] Recovery Boiler~~		{{Infobox industrial equipment
			\| name = Recovery Boiler
			\| image = [[File:SantaFeRecoveryBoiler.JPG\|thumb\|A recovery boiler in operation]]
			\| caption = A recovery boiler in operation
			\| uses = Recovery of chemicals and energy from black liquor
			\| industry = Pulp and paper industry
			}}

	A recovery boiler is a crucial component in the ~~chemical recovery process of a kraft~~ pulp ~~mill. It is designed~~ to ~~burn~~ black liquor, a byproduct of the ~~pulping process, to generate steam and recover chemicals for reuse in the pulping~~ process. ~~This article provides an~~ in~~-depth look at~~ the ~~design, operation~~, and ~~significance~~ of ~~recovery boilers in the pulp~~ and ~~paper industry~~.		A '''recovery boiler''' is a crucial component in the [[pulp and paper industry]], used primarily to recover chemicals and energy from [[black liquor]], a byproduct of the [[kraft process]]. The recovery boiler plays a vital role in the chemical recovery cycle, enabling the recycling of chemicals and the generation of steam and electricity.

	== ~~Design and Components~~ ==		==History==
			The development of the recovery boiler was a significant advancement in the kraft process, allowing for more efficient chemical recovery and energy production. The first recovery boilers were developed in the early 20th century, with significant improvements in design and efficiency occurring over the decades.

	A recovery boiler ~~consists of several key components that work together~~ to ~~achieve its dual purpose of energy generation~~ and ~~chemical recovery:~~		==Function==
			The primary function of a recovery boiler is to combust black liquor, which contains organic material and inorganic chemicals. The combustion process recovers the inorganic chemicals as a smelt, which is then processed to regenerate the cooking chemicals used in the kraft process.

	=== ~~Furnace~~ ===		===Combustion Process===
	~~The furnace~~ is the ~~primary chamber where~~ black liquor ~~is combusted~~. It is ~~lined with water-cooled tubes~~ that ~~absorb heat from the combustion process~~ to ~~generate~~ steam. ~~The furnace operates at high temperatures~~ to ~~ensure complete combustion of~~ the ~~organic material in the black liquor~~.		Black liquor is sprayed into the recovery boiler through specialized nozzles, such as the one shown in [[File:Black_liquor_nozzle.JPG\|thumb\|A black liquor nozzle]]. The liquor is burned in the furnace, releasing heat that is used to produce steam. This steam can be used to generate electricity or provide process heat for the mill.

	=== ~~Superheater~~ ===		===Chemical Recovery===
	~~The superheater~~ is ~~a set of tubes located in~~ the ~~upper part~~ of the boiler. ~~It heats the steam produced~~ in ~~the furnace~~ to ~~a higher temperature~~, ~~increasing its energy content and efficiency for use~~ in ~~turbines~~.		During combustion, the inorganic chemicals in the black liquor are reduced to a molten smelt, which is collected at the bottom of the boiler. This smelt is then dissolved in water to form green liquor, which is further processed to regenerate white liquor, the active cooking chemical in the kraft process.

	==~~= Economizer =~~==		==Energy Production==
	The ~~economizer~~ is a heat ~~exchanger that preheats the feedwater entering the boiler using the flue gases exiting the furnace~~. This process ~~improves~~ the ~~overall efficiency~~ of ~~the boiler by reducing the energy required to convert water into steam~~.		The recovery boiler is a significant source of energy for a pulp mill. The heat generated from burning black liquor is used to produce high-pressure steam, which can drive turbines to generate electricity. This process is illustrated in the [[File:NetheatingvalueBlackLiquor.jpg\|thumb\|Net heating value of black liquor]].

	==~~= Air System =~~==		==Environmental Impact==
	~~The air system supplies~~ the ~~necessary oxygen~~ for ~~combustion~~. ~~It typically includes primary, secondary, and tertiary air supplies to ensure complete combustion and control of~~ emissions.		Recovery boilers help reduce the environmental impact of the kraft process by recycling chemicals and reducing the need for fresh chemical inputs. They also reduce emissions by efficiently burning organic material in black liquor.

	~~=== Smelt Spouts and Dissolving Tank ===~~		==Challenges and Innovations==
	The smelt spouts are located at the bottom of the furnace and direct the molten smelt into a dissolving tank. The smelt contains inorganic chemicals that are recovered and recycled back into the pulping process.		Recovery boilers face challenges such as corrosion, fouling, and the need for efficient combustion. Innovations in materials, design, and control systems continue to improve the efficiency and longevity of recovery boilers.

	~~== Operation ==~~

	~~The operation of a recovery boiler involves several critical steps:~~

	~~1. '''Black Liquor Combustion:''' Black liquor is sprayed into the furnace, where it is combusted. The heat generated is used to produce steam.~~
	~~2. '''Steam Generation:''' Water in the boiler tubes absorbs heat from the combustion process, converting it into steam.~~
	3. '''Chemical Recovery:''' The inorganic chemicals in the black liquor are recovered as smelt, which is dissolved in water to form green liquor. This is further processed to regenerate white liquor for the pulping process.
	~~4. '''Emission Control:''' Modern recovery boilers are equipped with systems to control emissions of particulates, sulfur compounds, and nitrogen oxides.~~

	~~== Importance in the Pulp and Paper Industry ==~~

	Recovery boilers are vital for the economic and environmental sustainability of kraft pulp mills. They allow for the efficient recovery and reuse of chemicals, reducing the need for fresh chemical inputs. Additionally, the energy generated from burning black liquor contributes significantly to the energy needs of the mill, often making it energy self-sufficient.

	== Challenges and Innovations ==

	Recovery boilers face challenges such as corrosion, fouling, and ~~emissions control~~. Innovations in materials, design, and control systems continue to improve ~~their~~ efficiency and longevity. ~~Advanced monitoring and control technologies are being developed to optimize combustion and reduce emissions.~~

	~~== Also see ==~~

			==Also see==
	* [[Kraft process]]		* [[Kraft process]]
	* [[Black liquor]]		* [[Black liquor]]
	* [[Pulp mill]]		* [[Pulp mill]]
	* [[Chemical recovery]]		* [[Chemical recovery]]
	* [[Steam turbine]]

	{{Pulp and ~~Paper Industry~~}}		==References==
	{{~~Boiler Technology~~}}		* Smook, G. A. (1992). ''Handbook for Pulp & Paper Technologists''. Angus Wilde Publications.
			* Adams, T. N., & Frederick, W. J. (1988). ''Kraft Recovery Boiler Physical and Chemical Processes''. American Paper Institute.

			{{Pulp and paper industry}}
			{{Industrial equipment}}

	[[Category:Pulp and ~~Paper Industry~~]]		[[Category:Pulp and paper industry]]
	[[Category:~~Boilers~~]]		[[Category:Industrial equipment]]

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2024-12-09T15:44:00Z

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← Older revision		Revision as of 15:44, 9 December 2024
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	[[~~file~~:SantaFeRecoveryBoiler.JPG\|thumb~~\|SantaFeRecoveryBoiler~~]] [[~~file~~:~~Svartlut_76~~.jpg\|thumb~~\|Svartlut 76\|left~~]] [[~~file~~:EarlyTomlinsonRB.gif\|thumb~~\|EarlyTomlinsonRB~~]] [[~~file~~:~~Black_liquor_nozzle.JPG\|thumb\|~~Black liquor nozzle~~\|left]] [[file:NetheatingvalueBlackLiquor~~.~~jpg~~\|thumb~~\|NetheatingvalueBlackLiquor~~]] ~~[[file:DrySolidsvsYear.jpg\|thumb\|DrySolidsvsYear]] {{Short description\|Industrial boiler used in the pulp and paper industry}}~~		[[File:SantaFeRecoveryBoiler.JPG\|thumb]] [[File:Svartlut 76.jpg\|thumb]] [[File:EarlyTomlinsonRB.gif\|thumb]] [[File:Black liquor nozzle.JPG\|thumb]] Recovery Boiler
	~~{{Infobox boiler~~
	~~\| name =~~ Recovery ~~boiler~~
	~~\| image =~~
	~~\| caption =~~
	~~\| classification =~~ Boiler
	~~\| fuel type = Black liquor~~
	~~\| application = Pulp and paper industry~~
	~~\| inventor = G.H. Tomlinson~~
	~~\| year of invention = 1934~~
	}}

	A ~~'''~~recovery boiler~~'''~~ is a ~~type of industrial [[boiler]] used~~ in the [[pulp ~~and paper industry]]~~. ~~Its primary function~~ is to burn [[black liquor]], a byproduct of the ~~[[kraft~~ process]], to generate steam and recover ~~valuable~~ chemicals ~~used~~ in the pulping process. ~~The recovery boiler plays a crucial role~~ in the ~~[[chemical~~ recovery~~]] cycle of the kraft process, making it an essential component~~ in the ~~production of [[~~paper~~]] and [[pulp]]~~.		A recovery boiler is a crucial component in the chemical recovery process of a kraft pulp mill. It is designed to burn black liquor, a byproduct of the pulping process, to generate steam and recover chemicals for reuse in the pulping process. This article provides an in-depth look at the design, operation, and significance of recovery boilers in the pulp and paper industry.

	== ~~History~~ ==		== Design and Components ==
	~~The~~ recovery boiler ~~was invented by G~~.H. ~~Tomlinson~~ in ~~1934~~. ~~Before its invention,~~ the ~~recovery~~ of ~~chemicals from black liquor was inefficient~~ and ~~hazardous~~. The ~~introduction of~~ the ~~recovery~~ boiler ~~significantly improved~~ the efficiency ~~and safety~~ of the ~~chemical recovery process~~, ~~leading~~ to ~~widespread adoption in~~ the ~~pulp~~ and ~~paper industry~~.
			A recovery boiler consists of several key components that work together to achieve its dual purpose of energy generation and chemical recovery:

			=== Furnace ===
			The furnace is the primary chamber where black liquor is combusted. It is lined with water-cooled tubes that absorb heat from the combustion process to generate steam. The furnace operates at high temperatures to ensure complete combustion of the organic material in the black liquor.

			=== Superheater ===
			The superheater is a set of tubes located in the upper part of the boiler. It heats the steam produced in the furnace to a higher temperature, increasing its energy content and efficiency for use in turbines.

			=== Economizer ===
			The economizer is a heat exchanger that preheats the feedwater entering the boiler using the flue gases exiting the furnace. This process improves the overall efficiency of the boiler by reducing the energy required to convert water into steam.

			=== Air System ===
			The air system supplies the necessary oxygen for combustion. It typically includes primary, secondary, and tertiary air supplies to ensure complete combustion and control of emissions.

			=== Smelt Spouts and Dissolving Tank ===
			The smelt spouts are located at the bottom of the furnace and direct the molten smelt into a dissolving tank. The smelt contains inorganic chemicals that are recovered and recycled back into the pulping process.

	== Operation ==		== Operation ==
	The recovery boiler operates by burning black liquor, which contains organic materials and inorganic chemicals. The combustion process generates heat, which is used to produce steam. This steam can be used for various purposes, including powering [[turbines]] to generate [[electricity]] and providing process heat for the mill.

	The ~~inorganic chemicals in the black liquor, primarily sodium compounds, are recovered in the form~~ of a ~~molten smelt. This smelt is then dissolved in water to form [[green liquor]], which is further processed to regenerate the chemicals used in the kraft process.~~		The operation of a recovery boiler involves several critical steps:

	~~== Components ==~~		1. '''Black Liquor Combustion:''' Black liquor is sprayed into the furnace, where it is combusted. The heat generated is used to produce steam.
	~~A typical recovery boiler consists of several key components:~~		2. '''Steam Generation:''' Water in the boiler tubes absorbs heat from the combustion process, converting it into steam.
	* '''~~Furnace~~''': The ~~main combustion chamber where black liquor~~ is ~~burned~~.		3. '''Chemical Recovery:''' The inorganic chemicals in the black liquor are recovered as smelt, which is dissolved in water to form green liquor. This is further processed to regenerate white liquor for the pulping process.
	* '''~~Superheater~~'''~~: A set of heat exchangers that increase the temperature of the steam produced~~ in the boiler.		4. '''Emission Control:''' Modern recovery boilers are equipped with systems to control emissions of particulates, sulfur compounds, and nitrogen oxides.
	* '''Economizer''': A heat ~~exchanger that preheats~~ the ~~feedwater entering the boiler~~, ~~improving overall efficiency~~.
	* '''~~Air system~~'''~~: Supplies~~ the ~~necessary air~~ for ~~combustion~~.
	* '''~~Smelt spouts~~'''~~: Channels through which the molten smelt is discharged from the furnace~~.

	== ~~Advantages~~ ==		== Importance in the Pulp and Paper Industry ==
	~~The recovery boiler offers several advantages:~~
	* Efficient recovery of chemicals, reducing the need for fresh chemical inputs.
	* Generation of steam and electricity, contributing to the energy needs of the mill.
	* Reduction of environmental impact by minimizing waste and emissions.

	== Challenges ==		Recovery boilers are vital for the economic and environmental sustainability of kraft pulp mills. They allow for the efficient recovery and reuse of chemicals, reducing the need for fresh chemical inputs. Additionally, the energy generated from burning black liquor contributes significantly to the energy needs of the mill, often making it energy self-sufficient.
	~~Despite its advantages~~, ~~the recovery boiler also presents some challenges:~~
	* High capital and ~~maintenance costs~~.		== Challenges and Innovations ==
	* Potential for severe corrosion and ~~fouling due~~ to ~~the harsh conditions inside the boiler~~.
	* Safety risks associated with handling and ~~processing molten smelt~~.		Recovery boilers face challenges such as corrosion, fouling, and emissions control. Innovations in materials, design, and control systems continue to improve their efficiency and longevity. Advanced monitoring and control technologies are being developed to optimize combustion and reduce emissions.

			== Also see ==

	~~== See also ==~~
	* [[Kraft process]]		* [[Kraft process]]
	* [[Black liquor]]		* [[Black liquor]]
	* [[Pulp ~~and paper industry~~]]		* [[Pulp mill]]
	* [[Chemical recovery]]		* [[Chemical recovery]]
	* [[~~Boiler~~]]		* [[Steam turbine]]

	~~== Related pages ==~~		{{Pulp and Paper Industry}}
	* [[Kraft process]]		{{Boiler Technology}}
	* [[Black liquor]]
	* [[Pulp and ~~paper industry]]~~
	* [[Chemical recovery]]
	* [[Boiler]]

			[[Category:Pulp and Paper Industry]]
	[[Category:Boilers]]		[[Category:Boilers]]
	~~[[Category:Pulp and paper industry]]~~
	~~[[Category:Chemical processes]]~~
	~~[[Category:Industrial equipment]]~~

	~~{{Boiler-stub}}~~

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2024-05-30T05:07:43Z

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[[file:SantaFeRecoveryBoiler.JPG|thumb|SantaFeRecoveryBoiler]] [[file:Svartlut_76.jpg|thumb|Svartlut 76|left]] [[file:EarlyTomlinsonRB.gif|thumb|EarlyTomlinsonRB]] [[file:Black_liquor_nozzle.JPG|thumb|Black liquor nozzle|left]] [[file:NetheatingvalueBlackLiquor.jpg|thumb|NetheatingvalueBlackLiquor]] [[file:DrySolidsvsYear.jpg|thumb|DrySolidsvsYear]] {{Short description|Industrial boiler used in the pulp and paper industry}}
{{Infobox boiler
| name = Recovery boiler
| image =
| caption =
| classification = Boiler
| fuel type = Black liquor
| application = Pulp and paper industry
| inventor = G.H. Tomlinson
| year of invention = 1934
}}

A '''recovery boiler''' is a type of industrial [[boiler]] used in the [[pulp and paper industry]]. Its primary function is to burn [[black liquor]], a byproduct of the [[kraft process]], to generate steam and recover valuable chemicals used in the pulping process. The recovery boiler plays a crucial role in the [[chemical recovery]] cycle of the kraft process, making it an essential component in the production of [[paper]] and [[pulp]].

== History ==
The recovery boiler was invented by G.H. Tomlinson in 1934. Before its invention, the recovery of chemicals from black liquor was inefficient and hazardous. The introduction of the recovery boiler significantly improved the efficiency and safety of the chemical recovery process, leading to widespread adoption in the pulp and paper industry.

== Operation ==
The recovery boiler operates by burning black liquor, which contains organic materials and inorganic chemicals. The combustion process generates heat, which is used to produce steam. This steam can be used for various purposes, including powering [[turbines]] to generate [[electricity]] and providing process heat for the mill.

The inorganic chemicals in the black liquor, primarily sodium compounds, are recovered in the form of a molten smelt. This smelt is then dissolved in water to form [[green liquor]], which is further processed to regenerate the chemicals used in the kraft process.

== Components ==
A typical recovery boiler consists of several key components:
* '''Furnace''': The main combustion chamber where black liquor is burned.
* '''Superheater''': A set of heat exchangers that increase the temperature of the steam produced in the boiler.
* '''Economizer''': A heat exchanger that preheats the feedwater entering the boiler, improving overall efficiency.
* '''Air system''': Supplies the necessary air for combustion.
* '''Smelt spouts''': Channels through which the molten smelt is discharged from the furnace.

== Advantages ==
The recovery boiler offers several advantages:
* Efficient recovery of chemicals, reducing the need for fresh chemical inputs.
* Generation of steam and electricity, contributing to the energy needs of the mill.
* Reduction of environmental impact by minimizing waste and emissions.

== Challenges ==
Despite its advantages, the recovery boiler also presents some challenges:
* High capital and maintenance costs.
* Potential for severe corrosion and fouling due to the harsh conditions inside the boiler.
* Safety risks associated with handling and processing molten smelt.

== See also ==
* [[Kraft process]]
* [[Black liquor]]
* [[Pulp and paper industry]]
* [[Chemical recovery]]
* [[Boiler]]

== Related pages ==
* [[Kraft process]]
* [[Black liquor]]
* [[Pulp and paper industry]]
* [[Chemical recovery]]
* [[Boiler]]

[[Category:Boilers]]
[[Category:Pulp and paper industry]]
[[Category:Chemical processes]]
[[Category:Industrial equipment]]

{{Boiler-stub}}