Showing posts with label MPR E-Scan. Show all posts
Showing posts with label MPR E-Scan. Show all posts

Process Refractometers for Black Liquor and Green Liquor Processes in Pulp and Paper

Black liquor refractometer
The only thing that a pulp and paper plant doesn't reuse is the "shade the building casts". When you consider reuse of energy and byproducts, the processes used in the production of pulp and paper are very efficient. Efficiency is costly however, because of the very hostile environments and demanding operating conditions endured by the plant's process equipment.

As an example, the "Kraft Process" (also known as the sulfate process) is the method of converting wood chips into pulp and cellulose fibers. The wood chips are mixed with sodium hydroxide and sodium sulfate, then soaked, cooked and processed.


A very fundamental explanation of the Kraft Process:

Wood chips are soaked and processed as "white liquor" in a mixture of sodium hydroxide and sodium sulphates. After impregnating the wood chips with white liquor, they are then cooked in digesters to break wood into cellulose. The solid pulp is then separated and the rest of the fluid is called the "black liquor". Black liquor is also processed for the removal of solids and chemicals to be reused during pulping. One of the final by-products is "green liquor" which contains both sodium carbonate and sodium sulfide and is then reacted into more white liquor with the addition of lime. All of these processes expose instruments, processing equipment, piping and valves to very harsh environments and chemicals. 

Electron Machine Corporation, a manufacturer of extremely robust process refractometers, has for over 40 years, been actively perfecting the use of refractometers for the measurement of green and black liquor density. 

Scaling of the sensor head: A key issue for keeping the system operational.

heated high-pressure cleaning system
 MPR E-Scan and heated high-pressure cleaning system.
The problem of scaling in black liquor and green liquor applications is a major concern. It results in an optical coating on the sensor head of the refractometer the deteriorates performance. This scaling needs to be kept in-check in order to permit an acceptable duration of online measurement. With a means of effective removal at the time the the coating happens, the refractometer accuracy can maintained with minimum maintenance and downtime.

Electron Machine's decades of effort and experience in the pulp and paper industry led to the development of their MPR E-Scan refractometer in tandem with their heated high-pressure cleaning system. The resulting combination ensures efficient optical coating removal  and maintenance minimization so as to ensure a reliable measurement source for automatic online control.

For more information about the use of process refractometers in pulp and paper production contact Electron Machine Corporation by calling 352-669-3101 or visit their website at https://electronmachine.com.

Accurate Green Liquor Density Control with Reduced Maintenance

HPC-2 High Pressure Cleaner

In pulp and paper processing, the term "green liquor" refers to a by-product of kraft pulping. It is the dissolved concentration of sodium sulfide, sodium carbonate, and other compounds in solution from the recovery boiler. The measurement and control of its concentration is important in the pulp and paper production cycle. 

Inline refractometers are used to provide continuous density measurement of green liquor in the pulp mill. A major issue in handling green liquor is scale build up and the resulting optical coating on the refractometer sensing head. If scale build-up is controlled for an acceptable amount of time during processing, the maximum accuracy of the refractometer will be achieved and the overall quality of the pulping process is supported. Understandably, it makes great sense that a system of measuring scale potential and a means to automatically clean the sensing head should be implemented.

The Electron Machine MPR EScan is used to measure the green liquor dissolved density, or TTA, at two stages in the process: after the green liquor dissolving tank and after the green liquor clarifier. The inline measurement, with the refractometer sensing head installed directly in the main process lines, allows real-time control of green liquor dilution to meet target TTA set-points. The measurement is also used to indicate (and prevent) excessive green liquor density and the resulting dangerous impending crystallization within the dissolving tank, and lower the potential for scaling.

Scaling issues, and therefore accuracy problems, are further reduced with the use of ancillary inline cleaning systems that use pressurized water, heated to the process temperature, to effectively clean the refractometer optical components. The Electron Machine HPC-2 High Pressure Cleaner is one example of a completely integrated system.

The compound result of using a refractometer to keep green liquor density within optimal levels, plus an inline cleaning system, provides an excellent payback both quality control and also with associated maintenance requirements.

Refractometers for Food and Beverage Processing

Refractometers commonly used to detect sugar levels and properties of jams juices, beverages, dairy products and much more.

Electron Machine Corporation developed the first in-line process refractometer more than 50 years ago when orange juice was first concentrated. Since that time, their refractometers have been successfully applied on many more applications including the production of sucrose, fructose, dextrose, soft drinks, fruit juices, dairy, apple sauce, jams, jellies, beer, wine, coffee, tea, vegetable oils, tomato paste, ice cream and honey.

With an extremely durable Sapphire prism as its foundation, the Electron Machine MPR E-Scan combines accurate measurements with ruggedized components in the sensing head combining for years of of dependable and accurate service in harsh food production environments.

Inline Refractometer Adapters, Cleaning Systems & Isolation Valves

There are many different mounting adapters available for the MPR E-Scan refractometer. These adapters have been designed and modified with decades of field experience to provide the most successful installation for specific applications. The video below provides a quick visual tour of the most popular.

For more information visit http://www.electronmachine.com or call 352-669-3101.

Replace the Sensing Head on MPR E-Scan and MDS-Divert Systems

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.).

The MDS Monitor Divert System is a BLRBAC compliant Black Liquor solids monitoring system designed specifically for Black Liquor recovery boilers.

The following paper illustrates the correct way to replace the sensing head on MPR E-Scan and MDS-Divert Systems from Electron Machine Corporation.

Inline Refractometers for Measuring Black Liquor Evaporation

black liquor solids concentration
Measuirng black liquor solids concentration.

Introduction:

Refractometers have long proven to be the instrument of choice for black liquor solids concentration. Electron Machine Corporation of Umatilla, Florida pioneered this technology to accurately measure black liquor dissolved solids 5 decades ago. Their MPR E-Scan inline refractometer provides digital accuracy with rugged components required for years of reliable use when installed in harsh industrial environments. This combination allows for easy integration into a mill-wide monitor / control system providing operators the information needed for efficient and easy-to-service control.

Application:

An important and overlooked area for refractometers is the pulp washing operation. By monitoring the concentration output the washers can be balanced to meet the needs of the evaporation process and a mill is able to regulate the mixing liquor. This control allows a consistent concentration supply to the evaporators and boiler. This installation is simple and greatly reduces hand sampling.

MPR E-Scan
MPR E-Scan
Evaporation:

By installing the Electron Machine Corporation MPR E-Scan with Isolation Valve Adapters before and after each evaporator effect, the concentration and temperature output can be utilized to monitor efficiency, detect problems and operate economically. This monitoring allows control operators to adjust steam usage for optimal solids evaporation. Operators can determine if a quick flush cleaning can be performed to improve efficiency, prolonging the time between invasive, labor intensive cleanings. It also allows the detection of any problems before the liquor reaches the boiler, plus provides a consistent solids percentage for firing.

Conclusion:


With the addition of the Electron Machine Corporation MPR E-Scan to a mills process control system, a company can see increased profitability through the optimized control of steam usage, reduced labor cost from the reduction of offline hand sampling and the ability to prolong the time between labor intensive offline cleanings. This greater control provides more consistent firing solids allowing boilers to operator more efficiently.

Key Benefits:
  • Consistent black liquor solids
  • Minimize steam consumption
  • Economical operation
  • Optimize man hours
  • Reduce costly evaporator cleanings