Black Liquor Recovery Boilers

Recovery Boiler (courtesy of Wikipedia)

Article courtesy of Electron Machine Corporation

“Black liquor” is a term used for the waste products that result from the pulping process. The black liquor recovery boiler (BLRB) allows for the chemicals in the waste products to be reclaimed via combustion. These reclaimed chemicals are then utilized to both meet steam demands in the process and to generate electricity.

Modern day BLRBs are designed similarly to industrial boilers, typically as two drum designs, for operating pressure under 900 psi, or single drum designs, for operating pressure over 900 psi. The combustion gases utilized by the boilers can be sticky, so the BLRB furnaces are taller than their utility or industrial watertube counterparts. The amount of pulp producible by a particular mill directly correlates to the size of the BLRB. Small BLRBs process about 750,000 pounds of dry solids per day, and larger BLRBs process about six million pounds of dry solids per day. Precise attention and vigilant maintenance are required in order to maximize investment return for each particular boiler.

Black Liquor

In order to ensure stabilization of combustion, BLRBs are equipped with auxiliary burners which raise boiler temperature for the combustion process. The firing of the black liquor will eventually become self-sufficient. Combusting the black liquor allows for sulfur compounds used in the pulping process to be reduced to sulfide while inorganic chemicals essential to the process are melted down for reuse. The furnace vaporizes the black liquor as the liquor is sprayed into the furnace. Extra water is vaporized, and some of the combustion takes place as the black liquor falls to the furnace’s floor. The resulting molten smelt flows through spouts, which are operantly cooled via water, to a smelt dissolving tank.

A particular risk of the BLRB process stems from the relationship between molten smelt and water. The pool of molten smelt that accumulates as a result of the reclamation process needs to be kept separate from water, because water and molten material mixing at high temperatures can result in a smelt-water explosion. These explosions can occur when black liquor water content is greater than 42% of the mixture. Additionally, there are numerous ways water can enter the process – as condensation from the soot blower, a faulty steam coil heater, wash hoses – so controller vigilance is absolutely key to explosion prevention.

The Black Liquor Recovery Board Advisory Committee has recently introduced an emergency shutdown procedure, where an emergency evacuation alarm signals as soon as suspected water enters the BLRB furnace. The operator, with corresponding training, shuts down all fuel flow and minimizes combustion until all but a minimal amount of water is drained rom the BLRB. Annual inspections of BLRBs mandate the testing of all pressure parts and safety systems, because utmost care must be assured in preventing risk of system damage or operator harm when dealing with BLRB processes.

The World's Most Rugged Process Refractometer

Built for the most demanding industrial applications, Electron Machine process refractometers are designed from the ground up to handle abuse. From hot, dirty, and harsh environments in chemical plants and pulp mills, to the caustic wash downs and constant vibration in food and beverage processing, EMC process refractometers stand up to the punishment.

Electron Machine's reputation for building the world's most rugged process refractometer isn't an accident. They been providing durable, safe, reliable, and accurate process measurement and control instrumentation for more than 70 years. 

https://www.electronmachine.com

352-669-3101

Process Refractometers Maintain Product Quality in Commercial Food and Beverage Production

Process Refractometer (sensor)
(Electron Machine Corp.)

All commercial food products are selected on the basis of quality, freshness and affordability. Varying product quality is the best way to lose brand-loyal customers. Quality and consistency can be different between brands, but they cannot vary within a brand.

Manufacturers of juices, jellies, honey, wine, and carbonated beverages rely on the measurement of "Brix" to control product quality and consistency. Brix (symbol °Bx) is defined as 1 gram of sucrose in 100 grams of solution, and represents the strength of the solution as percentage by mass.

Examples of food and beverage products that need to carefully measure sucrose, fructose, and dextrose include soft drinks, fruit juices, dairy, apple sauces, jams, jellies, beer, wine, coffee, tea, vegetable oils, tomato products, and honey.  To do this, a device known as a refractometer is used to measure Brix (as well as other dissolved solids).

In smaller food and beverage applications, the refractometer is a handheld device used for batch sampling, but for high volume commercial processing, a more robust and heavy duty "process refractometers" is used. Sometimes referred to as "inline refractometers", these process instruments provide real-time, continuous measurement of Brix and dissolved solids.

Process Refractometer with
sensor mounted on sanitary
pipe shown with control box.
(Electron Machine Corp.)

This category of process refractometer is designed to provide very accurate and repeatable measurement for products flowing through a pipe or mixing in a vessel. They are designed to handle higher temperatures, resist contamination and corrosion, and they respond very quickly to any process deviation.

A process refractometer works by shining an LED light source from a range of angles, through a product sample, onto a prism surface. By measuring the difference in the reflection and refraction of the light source, a critical angle can be determined and the refractive index can be accurately calculated.  This measurement and calculation can be done accurately, repeatably, and quickly, making process refractometers the de-facto standard for the measurement of Brix in high production  food processing applications.

For more information on the use of process refractometers in food and beverage production, visit this link.

Happy New Year from Electron Machine

With 2017 coming to a close, all of us at Electron Machine wanted to reach out and send our best wishes to our customers, our vendors, and our friends! We hope that 2018 holds success and good fortune for all of you.

Literature Updates for Electron Machine

Electron Machine Corporation recently updated some of their product, application, and support literature. The new pieces are described and linked below:

Operating and Service Manual for MPR E-Scan

Service manual for the MPR E-Scan, a hybrid-digital critical angle in-line process refractometer. It is used to measure the refractive index of process fluids.

MDS (Monitor Divert System) Color Manual
Service manual for the Monitor Divert System, a BLRBAC (Black Liquor Recovery Boiler Advisory Committee) compliant Black Liquor solids monitoring system designed specifically for Black Liquor recovery boilers.

Refractometers for Food Industry

Brochure for refractometers used to detect sugar levels and properties of jams juices, beverages, dairy products and much more.

Refractometers for Chemical Industry

Brochure for the MPR E-Scan used for measuring the strength of a chemical when diluted with water or with another chemical.

MPR E-Scan Sales Brochure

The MPR E-Scan is a rugged, industrialized, in-line process refractometer. It directly measures the refractive index of process fluids and then displays the reading in any number of customer-desired units (Brix, Percent Solids, Dissolved Solids, SGU, R.I., etc.).

Quality and Process Optimization with Inline Refractometers

Process refractometer
in plant.

Process refractometer
(Electron Machine Corp.)

Refractometry is a technology used to quickly, reliably, and very accurately identify a sample and determine the concentration and purity levels. This is done be taking a sample and measuring the refractive index and temperature of the media.

Process refractometers are used for monitoring and controlling process variables in the flowing process media (liquid) . These instruments are used for continual, extremely accurate, real-time substance identification. Through identifying critical factors such as the concentration and purity, manufacturer's can gain tight control over quality can consistency of product. Applications for process refractometers are found in commercial food & beverage, chemical, pulp & paper, and pharmaceutical industries. All share similar processes lines where process refractometry provides real-time, high value information about the product at critical points. These shared processes are:

Process refractometers are used
for food and beverage production.

Concentration
The measurement of concentrations in compounds of organic chemicals, inorganic chemicals, and total dissolve solids are often required for product consistency. Process refractometers can be calibrated to detect a wide range of dilute chemicals and dissolved solids and be an excellent feedback mechanism for these process variables.


Mixing 
Using process refractometers for ingredient mixing to control product quality and production reduces errors and limits variance. Comparing the process media to known reference values, through the use of an inline refractometer, optimizes consistency and maintains quality.


Crystallization

Process refractometers are critical
for making pulp and paper.

Crystallization plays a key role in purification in many chemical processes, ranging from pharmaceutical manufacturing to food processing to liquor processing in pulp & paper production.  Keeping track of concentration levels is essential for the crystallization process and process refractometers provide real time information that allow process optimization.



Cleaning

Process refractometers
have many uses in
chemical production.

Changing product runs through existing lines is a major problem area for quality control. If a process line is used in the production of more than one product, it is important to ensure that no cross-product contamination occurs. To virtually eliminate this concern, process refractometers are used to check in for residual product presence (in real-time), providing assurance that purity levels are their highest.

For more information on industrial process refractometers, contact Electron Machine by visiting https://www.electronmachine.com or call 352-669-3101.

Inline Refractometers Used in Beet Sugar Processing

Beets are harvested late in the year and transported by truck to the beet sugar processing facility. The initial process involves washing (beets are dirty), and separation from leaves, stones and other miscellaneous debris. After cleaning, the beets are cut in to thin slices making juice extraction easier.

Juice extraction is done in an agitated hot water diffuser tank that continuously agitates the dilution until the concentration reaches the level that qualifies as juice. Other components and impurities from the beet flesh and skins are also dissolved in the juice which later have to be removed.

The raw juice is then put through a process call "Carbonatation" that introduces a calcium hydroxide suspension and carbon dioxide under controlled conditions of pH and temperature. This process coagulates impurities and decolorizes the raw juice. The impurities are separated from the clear liquor and calcium carbonate by pressure filtration. The clear liquor is then sent to a multi-stage evaporator to remove water and create syrup.

The syrup is then placed in large boiling pans which boils off remaining water and initiates sugar crystallization. The crystals are then spun to separate them from any remaining mother liquor.

Electron Machine MPR E-Scan

To achieve high quality liquid and crystal sugars, improve efficiency and keep production cost in check, refractometers are employed to deliver accurate in-line Brix and other dissolved solids measurements in the beet sugar refining, evaporation and boiling processes.

In beet sugar refineries, the Electron Machine MPR E-Scan can be used to monitor and control Brix measurement from the beginning of the evaporation stages up to the seed point of crystallization.

Visit Electron Machine at https://www.electronmachine.com or call 352-669-3101.