What is Refractometer Critical Angle Measurement?

Vaisala refractometers use the critical angle measurement principle. A refractometer's three essential components are a light source, a prism, and an image detector. 

DOWNLOAD THE REFRACTIVE INDEX MEASUREMENT PAPER HERE

The light source sends rays to the prism and process interface at different angles. Rays with a steep angle partly reflect at the image detector and partially refract at the process. Low-angle rays reflect entirely on the detector. The angle from which the total reflection starts is called the critical angle. 

The CCD camera detects a bright and dark field corresponding to partly reflected and totally reflected light. The position of the borderline between the bright and the dark area correlates with the critical angle, which is a function of the refractive index and correlates with the solution's concentration.

A built-in temperature sensor measures the temperature T on the interface of the process liquid. The sensor converts the refractive index nD and temperature T into concentration units. 

Vaisala K-PATENTS refractometer can indicate different scales, for example, Brix, liquid density, or concentration by weight. The diagnostics program ensures that the measurement is reliable.

Miller Energy, Inc.

800-631-5454

https://millerenergy.com

Brooks Instrument GP200 Pressure-based Mass Flow Controllers (MFC): Theory of Operation

Brooks Instrument presents the theory of operation behind their pressure-based mass flow controller (P-MFC) from their GP200 series in this video. This P-MFC has a unique design approach for enhanced process performance without the limitations of today's traditional P-MFCs. A traditional P-MFC system includes:

• An upstream pressure transducer.
• An upstream control valve.
• Two individual pressure transducers.
• Laminar flow element.

The use of an upstream valve has many disadvantages. This design requires high pressure making it sub-optimal for critical low-pressure gases and low full-scale flow rate. It also means matching the two individual pressure transducers perfectly. 

Brooks Instrument designed a patented integrated differential pressure transducer, GP200 P-MFC, to address the disadvantages. The GP200 has one actual differential transducer instead of two, eliminating the need to match the two individual pressure transducers, significantly reducing measurement uncertainty, and improving accuracy, particularly for critical low vapor pressure process gases. Its downstream valve architecture will operate at much lower inlet pressures and across a broader range of pressures. The downstream valve also minimizes the bleed-down effect and ensures that the device is insensitive to dynamic outlet conditions.

The GP200 Series P-MFC features a patented architecture that overcomes the limitations of conventional P-MFCs to provide the most precise process gas delivery even when delivering low vapor pressure process gases. It includes several unique design aspects, including an integrated differential pressure sensor coupled with a downstream valve architecture enabling the most precise process gas delivery over the industry's broadest range of operating conditions.

Since GP200 Series supports a broad range of process conditions, it can be used as a drop-in replacement and upgrade for many traditional P-MFCs and thermal MFCs. It reduces the complexity and cost of ownership of the gas delivery system because it eliminates the need for components such as pressure regulators and transducers.

GP200 FEATURES

• True differential pressure measurement
• Lower inlet pressure operation
• Downstream valve architecture
• Matched transient response
• Zero Leak-by Control Valve
• MultiFlo™ technology offers unparalleled flexibility—one device can be programmed for thousands of different gas and flow range configurations without removing the MFC from the gas line or compromising accuracy
• Local display indicates flow, temperature, pressure and network address
• DeviceNet™, EtherCAT®, RS-485 L-Protocol and analog interfaces

GP200 BENEFITS

• By removing the requirement to match and compensate two separate pressure transducers, the GP200 differential pressure technology reduces measurement uncertainty for enhanced accuracy, repeatability and drift performance.
• Safer fab operation at lower inlet pressures is now achievable with a P-MFC due to the GP200 differential pressure sensor that is specifically optimized for low differential pressure measurement.
• The downstream valve architecture ensures accuracy is independent of downstream pressure, enabling flow delivery into pressures as high as 1200 Torr. The fast closing valve addresses non-productive recipe wait times, or "tail effects," seen in upstream MFC valve designs that require additional time to bleed down their internal volume of gas.
• Ultra-fast, highly repeatable ascending and descending flow stabilization time enables tighter process control in advanced high cycle Deposition and Etch processes.
• 100X improvement in valve shut-down
• With MultiFlo™, MFC full scale flow range can be re-scaled down typically by a factor of 3:1 with no impact on accuracy, turndown or leak by specifications, for optimum process and inventory flexibility 
• Convenient user display and independent diagnostic/service port aids device installation, monitoring and troubleshooting

For more information about Brooks Instrument products, contact Miller Energy, Inc. Call 800-631-5454 or visit https://millerenergy.com.

Miller Energy Is a Premier Manufacturer's Representative and Distributor of Process Instrumentation, Valves and Process Equipment

Miller Energy is an Industrial Instrumentation and Process Control Equipment Manufacturer's Representative and Distributor. We have been committed to exceeding our customers' expectations by providing unrivaled customer service and local technical support since 1958. We currently offer the most comprehensive range of measurement, control, and communication solutions in the industry.

Miller Energy provides a wide range of instrumentation and control solutions to many markets, including refining, water treatment, chemical production, and food and beverage. Miller's products are useful in applications that require measuring, controlling, monitoring, and analyzing pressure, temperature, level, flow, pH, O2, CO2, and various other process variables.

Miller Energy comprises the most technically savvy salespeople in the industry. All Field Sales Engineers are factory trained on all of our product lines. All Inside Sales/Technical Support Engineers are responsible for a specific product line and support our entire customer base. Intelligent geographic product distribution provides the most timely delivery for greater customer satisfaction.

Miller Energy has four office locations:

• The South Plainfield, NJ, corporate headquarters serves Northern New Jersey, New York, and Fairfield County, Connecticut. 
• The Exton, PA office serves Southern New Jersey, Eastern Pennsylvania, Delaware, and Maryland. 
• The Pittsburgh, PA location serves Western Pennsylvania, Western Maryland, and West Virginia. 
• The Cleveland, OH office serves Ohio. 

Miller Energy, Inc.

https://millerenergy.com

In New York Metro and Northern NJ

Phone: 800-631-5454

In Eastern Pennsylvania and Delaware:

Phone: 610-363-6200

In Western Pennsylvania:

Phone: 412-257-0200

In Ohio:

Phone: 440-735-0100

Selecting Variable Area Flow Meters for Process Flow Measurement

Many industrial processes involve the movement of fluid product components, either liquid or gaseous, through pipes. Because processing is about control, an input to the facility's management, measurement, or data logging centers will answer the query, "How much is going through that pipe?" 

In the industrial process measurement and control industry, there are several ways for quantifying flow, each with unique characteristics that may be useful under certain operating situations. All flow measuring methods are indirect because the actual measurement is of a character influenced predictably by a change in the media flow. Flow measurement is a critical component that, when paired with other fluid properties, is used to calculate the total mass of a fluid passing through the measurement site. 

The variable area meter, commonly known as a rotameter and VA meter, is a tried and true flow measuring device that operates by creating an equilibrium between an upward force created by fluid motion and a downward force, gravity. A tapering glass or metal tube encases a specifically shaped float, also known as a shaped weight, in the device. VA meters must be positioned vertically, with the media flowing upward from the bottom, so that the gravity force required for functioning is correctly aligned with the flow direction. As fluid flows upward via the precisely tapered tube, drag is created on the float enclosed within the tube, pulling it upward. As the float rises, the open space between the float and the tube wall expands, causing the fluid velocity and drag force to decrease. The flow velocity within the tube will cause the weight to climb for any given flow volume until the drag force generated by the flow reaches equilibrium with the countervailing power of gravity on the float. The tube and float are well designed, allowing for an immediate indication of flow volume.

Variable area flowmeters have the following operating characteristics: 

• There is no need for external power or fuel for functioning. 
• Vertical installation is required, with flow arriving at the bottom. 
• Meters are calibrated to a given chemical and temperature. 
• The operation is stable and has a modest pressure drop. 
• For operation, constant gravity is required. 
• Flow rate can be read locally using a meter or a scale inscribed on the tube. 
• The visibility of the float through the medium is required for unit flow readings using glass tubes. 
• For industrial flow metering equipment, accuracy is relatively low. 
• Inexpensive upkeep, simple construction, and low comparative cost.

Brooks Instrument, a world-renowned maker of flow, pressure, and level measurement equipment, created a brief paper highlighting the parameters to consider when specifying a VA meter and how each aspect influences the unit's performance. The description is realistic and straightforward to grasp. It is suggested reading for all process stakeholders who want to improve their flow measuring skills.

For more information about variable area flow meters contact Miller Energy. Call 800-631-5454 or visit https://millerenergy.com.

Process Refractometers for Water Treatment Chemical Concentration Monitoring

INTRODUCTION

Pure water treatment removes undesirable chemicals, biological contaminants, suspended solids, and gases from raw water. Water purification aims to produce water for a specific purpose, such as human consumption and medical or industrial use.

Polyaluminium coagulants are increasing use in potable water treatment plants, particularly for soft, colored surface waters. Polyaluminium chloride (PACl) is gradually replacing Alum (aluminum sulfate), a commonly used coagulant in water treatment plants. Alum coagulates at a limited pH range (between 5.5 and 6.5) and often requires alkali to the raw water to achieve the optimum coagulation pH. Furthermore, the alum floc produced is particularly fragile, which is vital if a coagulant is required to maximize color removal in a microfiltration-based water treatment process.

APPLICATION

Water treatment by chemical precipitation is a complex process. It starts with adding flocculants, specifically, Polyaluminium Chloride (PACl) and Sodium Hydroxide (NaOH). PACl is a synthetic polymer dissolved in water. It precipitates in big volumetric flocs, which absorb suspended pollutants in the raw water. The turbidity of the raw water defines Polyaluminium Chloride quantity. PACl concentration must be higher than 10 % To keep the flocculation process smooth. Polyaluminium Chloride is stable in the storage tank; however, it tends to crystallize after some time. Vaisala K-PATENTS® refractometer monitors the concentration of PACl to inform about the need for tank or pipe cleaning, thus preventing blockage caused by the PACl crystals.

NaOH regulates pH level, increases alkalinity, and neutralizes acids in the water. In alkaline water, the coagulation and flocculation processes work more effectively. Moreover, sufficient alkalinity prevents dissolving the lead from pipes and pipe fittings and reduces the corrosive effect of the water to iron pipes.

Further, particles suspended in water start to precipitate and agglomerate to form larger particles, known as flocs. The flocs are then settled at the bottom, forming sludge, and then removed from the process. After separating most of the floc, the remaining suspended particles and unsettled floc get filtered to remove water.

In the filtration phase, the water goes through the layers of anthracite, sand, and gravel. As a result, organic compounds contributing to taste and odor get removed. Other remaining particles get trapped by adhering to the sand and gravel particles.

After harmful micro-organisms get removed through filtering, it is necessary to add disinfecting chemicals to the water to inactivate any remaining pathogens and potentially harmful micro-organisms. One of the disinfecting chemicals used is Sodium Hypochlorite (NaOCl). When dissolved in water, this chemical releases chlorine, which is an efficient and safe disinfectant if added in a sufficient amount. Apart from sodium hypochlorite, liquid chlorine and chlorine dioxide are also choices as disinfectants.

Fluoride may also be added to the water to reduce tooth decay and prevent chronic diseases. However, fluoride in the water must not exceed recommended levels. Excessive levels of fluoride can be toxic or cause undesirable cosmetic effects such as staining of teeth.

Sodium Hypochlorite is unstable and quickly decomposes. The stability of NaOCl solution is dependent on the following factors:

• Hypochlorite concentration
• The temperature of the solution
• PH value of the solution
• The concentration of the impurities during catalyzing decomposition
• Exposure to light

With the process refractometer, it is possible to monitor NaOCl concentration and control the disinfection conditions.

The water purification disinfection stage happens in the disinfectant basin. Then, corrosion control assures the high quality of the purified water. Finally, the pure water gets stored for further consumption.

INSTRUMENTATION AND INSTALLATION

Vaisala K-PATENTS® Teflon Body Refractometer PR-23-M provides in-line measurements of Polyaluminium Chloride and Sodium Hydroxide at the initial stage of purification, ensuring the efficient flocculation of undesired particles. In addition, through the measurement of Sodium Hypochlorite and Fluoride at the water disinfection stage, high-quality purified water at the outlet is assured.

Refractometer installations happen in three different points in a by-pass loop between each chemical tank pump outlet and the treatment point. The refractometer allows monitoring the chemicals concentration at the exit from the storage tank to the pipe treatment point.

Typical measurement ranges are:

• PACl is ca. 10-11 %
• NaOH is ca. 40-45 %
• NaOCl is ca. 8-12 %

Miller Energy, Inc.
https://millerenergy.com
800-631-5454

How Does a 250:1 Turndown Improve Your Bioprocess Performance?

The Brooks Instrument SLA Series Biotech Mass Flow Controller (MFC) with a 250:1 turndown delivers critical benefits to your bioprocess. This biotech-focused MFC provides the added flexibility of a higher controllable range than a traditional MFC, enabling easy scaling and reducing the total cost of ownership by requiring fewer gas lines and mass flow controllers in the system configuration. Performance of the bioprocess also improves by reducing DO noise while fewer overall components simplify system maintenance. 

For more information about Brooks Instrument products, contact Miller Energy by calling 800-631-5454, or visit https://millerenergy.com.

Understanding Safety Integrity Level (SIL)

Nothing is more important than safety to the process control industries. High temperature and pressure, flammable and toxic materials are just some of the issues faced on a daily basis. Reliability is a key component of safety; the more reliable the device, the safer the critical process.

Safety integrity level (SIL) is defined as "relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction." SIL ratings are applied in accordance of frequency and the severity of the hazard. These ratings determine the level of performance required to achieve and maintain safety, as well as the probability of failure.

There are four SIL levels; SIL 1, SIL 2, SIL 3, and SIL 4. These SIL levels relate to the risk of failure - a higher the SIL rating poses a higher risk of failure, in turn requiring stricter safety requirements.

Magnetrol, a leading manufacturer of innovative level, flow and volume controls for the process industries has put together this excellent technical note to help you better understand Safety Integrity Level.

DOWNLOAD THE MAGNETROL TECHNICAL NOTE ON UNDERSTANDING SAFETY INTEGRITY LEVEL FROM THIS MILLER ENERGY WEB PAGE

Miller Energy, Inc.
https://millerenergy.com
800-631-5454

Don’t Let Valves Come Between You and Accurate Flow Measurement

Getting valves and flow meters to work together is sometimes a challenging task within industrial water and wastewater applications. Valves tend to create the kind of irregular media flow patterns in pipelines that make it a real challenge to achieve accurate flow measurement of liquids, gas or steam. That’s why many types of popular liquid flow meters require straight pipe runs.

Unfortunately, the nature of the process or the kind of space required for long straight runs of pipe is often an impossible luxury in many of today’s plants.

How Valves Create Flow Disturbances

Depending on a pipeline’s flowing media (liquid, gas or steam), the process pressures and the process temperatures, the fluid flow dynamics within a pipeline can vary widely. The ideal pipeline configuration for the accurate measurement of flow with nearly all of the industry’s most popular flow sensors is a straight pipe with consistent media conditions Many processes by their very nature, however, tend to be unstable and create irregular flows within a pipeline all by themselves.

Plant layouts, especially expansions and retrofits, also tend to create less than optimum pipeline conditions for the measurement of flow. The addition of valves, pumps, elbows and other equipment into the pipeline create media swirling and other effects that can result in irregular flow profiles that will reduce flow meter measurement accuracy and repeatability. That’s why many flow meter manufacturers recommend anywhere from 5 to 10 or even 20 to 30 pipe diameters of straight pipe run upstream and downstream of the flow meter—depending on the flow sensing technology in use.

Flow Straightening and Conditioning

While the simple solution is to know your flow meter and its straight pipe run requirements to achieve accurate, consistent measurement, this is often easier said than done. Today’s complex and ever changing industrial processes, the need to treat and conserve water, crowded plant environments where real estate is precious, regulatory requirements and the team involved in running any plant can mean that your valve or elbow inevitably intrudes on your flow meter’s turf. Many times the first sign of the problem is when the flow meter isn’t reading the flow accurately. By then changing the pipeline layout or moving other devices such as valves is impractical and too costly.

Flow straighteners and conditioners offer an answer to this problem. There are several different types of flow straighteners and conditioners, including perforated plates, tube bundles, etc. The purpose of all flow straighteners and conditioners is to eliminate swirl and provide a stable velocity flow profile. Of course the ideal time to think about flow conditioning is before the flow meter is installed so that the flow conditioner and flow meter can be calibrated to work together. One drawback to add-on flow conditioners and straighteners is that they increase head loss.

Flow Meters With Built-In Conditioning

Another solution to consider is the installation of a flow meter with built-in flow conditioning. This type of solution offers the advantages of installation flexibility, reduced equipment, simplified installation with potentially fewer pipe penetrations and reduced maintenance requirements. Several manufacturers offer flow meters that include built-in flow conditioning. For example, McCrometer’s V-Cone Flow Meter is a differential-pressure sensing meter with integral flow conditioning that operates within liquids, gas or steam.

McCrometer’s V-Cone Flow Meter

The V-Cone’s DP flow sensor conditions fluid flow to provide a stable flow profile that increases accuracy. The flow sensor‘s design features a centrally-located cone inside a tube. The cone interacts with the fluid flow and reshapes the velocity profile to create a lower pressure region immediately downstream. The pressure difference, which is exhibited between the static line pressure and the low pressure created downstream of the cone, can be measured via two pressure sensing taps. One tap is placed slightly upstream of the cone and the other is located in the downstream face of the cone itself. The pressure difference can then be incorporated into a derivation of the Bernoulli equation to determine the fluid flow rate.

The cone’s central position in the line optimizes the velocity of the liquid flow at the point of measurement. It forms very short vortices as the flow passes the cone. These short vortices create a low amplitude, high frequency signal for excellent signal stability. The result is a highly stable flow profile for measurement accuracy to +0.5% with +0.1% repeatability over a wide flow range of 10:1. All of this is possible with a minimal straight pipe run of 0 to 3 diameters upstream and 0 to 1 diameters downstream from the flow meter depending upon placement from valves and other control devices.

Conclusions

Getting accurate flow measurement with valves, pumps, and other equipment in relatively close proximity is difficult, but achievable. The ideal way to achieve accurate and repeatable flow measurement within industrial water and wastewater applications is to recognize in advance the straight pipe run requirements of the flow sensing technology in use at your plant. When the process, the plant layout or other factors lead to swirl in your pipeline that affects meter performance, then consider either flow conditioners or a flow meter with built-in flow conditioning.

Attribution: Original white paper written by Jim Panek, Product Manager, Water & Wastewater, McCrometer, Inc.

How Do Magnetic Level Indicators Work?

Magnetic Level Indicators also known as MLIs, have revolutionized the global visual indication market by offering a safer, reliable, and high-visibility alternative to common gauge glass assemblies.  They provide high-visibility representation of the liquid level in a vessel. MLIs can be mounted to tanks in a number of different ways. The most popular configuration, however, is called a side-mount.

The Magnetic Level Indicator (MLI) working principle is widely used in many industrial level applications. The operating principle behind a magnetic level indicator is that the MLI shares the same process fluid as the vessel, and therefore shares the same level.

The three primary components to a Magnetic Level Indicator are:

• The float
• The chamber
• The visual indicator

The float (contained within the chamber) interacts with the externally mounted visual indicator. As liquid rises and falls in the vessel and MLI chamber, the float follows. The magnets in the float interact with magnets inside each indicator flag. As the float rises and falls in the chamber, the magnets slowly turn each flag 180 degrees. This allows the visible flag color to change to a high-contrasting, highly-visible representation of liquid level.







Utilizing a combination of proven buoyancy principles along with the benefits magnetism, MLIs can be customized to fit virtually any process connection arrangement on the vessel.

The chamber and magnetic float is available in a variety of materials and pressure ratings to accommodate the wide variety of complex process applications present in the world’s major industrial facilities.

Areas Where Magnetic Level Indicator Are Applied:

• Feed water heaters and boilers
• Refinery and chemical industries
• Energy and power plant technology
• Pulp and paper applications
• Oil and gas industries
• Gas plants
• Pipeline compressor applications
• Pharmaceutical applications
• Food and beverage applications

For more information about Magnetic Level Indicators (MLI's), contact Miller Energy by calling 800-631-5454 or visit their web site at https://millerenergy.com.

Process Instrumentation and Valves for the Chemical and Petrochemical Industries

Miller Energy provides process control instruments and valves designed to assist in higher quality yields, more efficient processes, and greater plant safety for chemical processing and petrochemical refining manufacturing facilities. 

The Chemical Industry

The chemical industry is key to industrial production. It transforms the raw materials of animals, vegetables and minerals into a host of products used by both the industrial and domestic customers. Lightweight and durable plastic products contribute to fuel effectiveness in transportation, energy-saving insulation material in buildings, paints and protective coatings that extend metal and wood life, soap, shampoo and detergents maintain us clean, pharmaceuticals and disinfectants protect our health. Without vital chemicals, computers and telecommunications systems could not work.

The industry has matured using local resources such as salt, coal, lime, vegetable products and animal fats. It is now a worldwide sector that mainly uses natural gas and oil fractions such as naphtha as the main raw materials. There is a strong awareness of the need to substitute fossil resources both as raw materials and for process energy with sustainable options.

The Petrochemical Manufacturing Industry

The sector produces petrochemicals which are petroleum and natural gas chemicals (organic compounds not burned as fuel). Ethylene, propylene, butylene, benzene, toluene, styrene, xylene, ethyl benzene and cumene are key products. These products are fundamental construction blocks in the manufacturing of consumer products, automotive parts and numerous sustainable and unsustainable goods. These products are fundamental construction blocks in the manufacturing of consumer products, automotive parts and numerous durable goods. This sector does not include organic compounds such as ethyl alcohol and inorganic chemicals such as carbon black.

Olefins and aromatics constitute the building blocks of a large variety of products, including solvents, detergents and adhesives. Polymers and oligomers used in plastics, resins, fibers, elastomers, lubricants and gels are built upon olefins.

Miller Energy: Chemical and Petrochemical Instrumentation and Valve Experts

Miller Energy offers a broad range of instrumentation and valves for these diverse markets. Since 1958, Miller Energy, Inc. has exceeded customers expectations in the Chemical and Petrochemical Industries by specifying and providing the highest quality instrumentation and valves. Known for unparalleled customer service and local technical support, Miller's comprehensive line of pressure, temperature, level, flow and analytical products are available now and ready to solve your most challenging chemical and petrochemical applications.

Contact the Miller Energy office in your area by visiting this web page, or call 800-631-5454 for further assistance.

Installing the ASCO 212 Series Composite Valve Using the FasN Connection System

The ASCO series 212 composite valve is intended for use in applications for water purification and water treatment, especially in the implementation of the membrane-based filtration. The composite valve series 212 is perfect for use in mid-size Reverse Osmosis Systems apps requiring lead-free and NSF-approved construction. The series 212 composite valves are available in 3/8", 1/2", 3/4", and 1" pipe sizes rated for pressures up to 150 PSIG and 180 degrees F.

The video above demonstrates how to install the series 212 using the patented ASCO FasN system for NPT threaded connections, turn and lock connections, and solvent bond connections.

For more information, contact Miller Energy Inc. by calling 800-631-5454 or visit their web site at https://millerenergy.com.

Refractometry in Oil Refining and the Petrochemical Industry: Sulfuric Acid Alkylation

SULFURIC ACID, H₂SO₄

Typical end products

• Alkylate (premium higher-octane gasoline blending stock for motor fuel and aviation gasoline).

Chemical curve: Sulfuric acid 88-100 R.I. per Conc wt.-% at Ref. Temp. of 20 ̊C

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DOWNLOAD THE PDF VERSION OF THIS APPLICATION NOTE
FROM THE MILLER ENERGY WEB SITE HERE

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Introduction

Motor fuel alkylation using sulfuric acid (H2SO4) or liquid hydrofluoric acid (HF) is one of the oldest catalytic processes used in petroleum refining. The purpose of the alkylation is to improve motor and aviation gasoline properties (higher octane) with up to 90 % lower emissions compared to conventional fuel usage.

The problem with HF is that the catalyst forms a hazardous air pollutant when released as a superheated liquid, while H2SO4 does not. Therefore nearly 90 % of all alky units built since 1990 have adopted the H2SO4 technology. 

The leading alkylation unit licensor, with a 90 % share of the market, is DuPont (Stratco®). Another licensor is EMRE (Exxon Mobile Research Engineering, formerly K.W. Kellogg).

Application

In the process, isobutane is alkylated with low molecular weight olefins (propylene, butylene and pentylene) in the presence of a strong acid catalyst to form alkylate (the premium higher-octane gasoline blending stock). The catalyst (sulfuric acid) allows the two-phase reaction to be carried out at moderate temperatures. The phases separate spontaneously, so the acid phase is vigorously mixed with the hydrocarbon phase to form higher molecular weight isoparaffinic compounds.

After the reactor, the mixture enters a separation vessel where the acid and hydrocarbon separate. The acid is then recycled back to the reactor.

Instrumentation and installation

The K-Patents Process Refractometer PR-43-GP is installed after the settlers to continuously monitor in real-time the concentration of acid in the process.

The concentration of sulfuric acid is critical to achieve the complete consumption of isobutane. A highly variable concentration of isobutane in the feedstock upsets the sulfuric acid content in the process.

It is important to determine the proper quantity of acid that will be fed into the process. This is achieved by combining routine sample titration analysis with continuous acid monitoring by the K-Patents Process Refractometer. Real-time measurements reduce the need for sampling and laboratory analyses that cause delay in the implementation of any necessary adjustments to the acid flow.

Continuous monitoring removes the uncertainty involved between titration measurements. The K-Patents refractometer will indicate any gradual fluctuations in the acid flow, allowing precise control over efficient acid consumption and resulting in cost savings. It is also useful in preventing acid runaway, an unwanted situation commonly described as wild acid.

Acid runaway may happen when the acid strength drops below 85-87 % H2SO4. As a result, the reactions between olefins and isobutane turn into reactions of olefins only, producing polymers known as acid sludge, ASO or red oil.

The K-Patents refractometer is not affected by acid soluble oil (ASO). The refractometer indicates actual acid strength regardless of the amount of hydrocarbons present, which is essential when transferring acid emulsion. It is also an extremely useful tool in real-time process acid strength measurement during agitated conditions.

The initial acid concentration is typically 85-100 % and the temperature is 15 °C (59 °F). The benefits of the K-Patents refractometer’s continuous monitoring system include substantial cost savings due to reduced acid consumption, and smooth alkylate production without acid runaways.

The K-Patents Process Refractometer System for Alkylation Acid Measurement Consists of:

1. The K-Patents Process Refractometer PR-43 for hazardous locations in Zone 2. or The K-Patents PR-43 Intrinsically Safe model for installations in hazardous locations up to Zone 0.
2. Optional parts:
   1. Different flow cell options for easy sensor installation
   2. EXd enclosure for easy isolator and transmitter mounting
   3. Parts for a start up
   4. Spare parts supplied for two years of operation
   5. Start-up and commissioning service
3. User specified tests and documentation.

Alloy C-276/ASTM C276 should be considered as wetted parts material when the acid piping flow velocity is at a maximum of 6 m/s (20 ft/s). Alloy 20 can be considered when acid piping flow velocity is at a maximum of 1.8 m/s (6 ft/s). However, it is the responsibility of the end-user to specify the appropriate material, ensuring that it is satisfactory for the intended operating requirements.

Non-sparking incentive (Ex nA) and intrinsic safety (Ex ia) approvals are available for hazardous area installations.

Always consult an applications expert with any process-critical instrumentation application. By doing so, you will ensure a successful, safe, and efficient deployment.

Miller Energy, Inc.
https://millerenergy.com
800-631-5454

Reprinted with permission from K-Patents.

Hazardous Areas: Division and Zone Classification System

Hazards areas are associated with flammable
vapors or gases, ignitable fibers, and combustible dusts.

Hazardous areas refer to locations with a possible risk of explosion or fire due to dangerous atmosphere. The hazards can be associated with flammable vapors or gases, ignitable fibers, and combustible dusts.

Different hazardous area classifications exist in the North America and Europe. Generally, the National Electric Code (NEC) classifications govern hazardous areas in the US. While in Europe, hazardous area classification has been specified by the International Electrotechnical Commission (IEC).

Below is a description of the Division and Zone classification system.

CLASS	NATURE OF HAZARDOUS MATERIAL
CLASS I	Hazardous area due the presence of flammable vapors or gases in sufficient quantities to produce ignitable mixtures and cause an explosion. Examples include natural gas and liquified petroleum.
CLASS II	Hazardous area due the presence of conductive or combustible dusts in sufficient quantities to produce ignitable mixtures and cause an explosion. Examples include aluminum and magnesium powders.
CLASS III	Hazardous area due the presence of flammable fibers or other flying debris that collect around lighting fixtures, machinery, and other areas in sufficient quantities to produce ignitable mixtures and cause an explosion. Examples include sawdust and flyings

Division groups hazardous areas based on the chances of an explosion due to the presence of flammable materials in the area.

DIVISION	LIKELIHOOD OF HAZARDOUS MATERIAL
DIVISION 1	Areas where there is a high chance of an explosion due to hazardous material that is present periodically, intermittently, or continuously under normal operation.
DIVISION 2	Areas where there is a low chance of an explosion under normal operation.

Group categorizes areas based on the type of flammable or ignitable materials in the environment. As per NEC guidelines, Groups A to D classify gasses while Groups E to G classify dust and flying debris.

GROUP	TYPE OF HAZARDOUS MATERIAL IN THE AREA
GROUP A	Acetylene.
GROUP B	Area contains flammable gas, liquid, or liquid produced vapor with any of the following characteristics: Minimum Ignition Current (MIC) value equal to or less than 0.40 Maximum Experimental Safe Gap (MESG) value equal to or less than 0.45 mm Combustible gas with more than 30 percent volume Examples include hydrogen, ethylene oxide, acrolein, propylene oxide.
GROUP C	Area contains flammable gas, liquid, or liquid produced vapor with any of the following characteristics: Minimum Ignition Current (MIC) value between 0.40 and 0.80 Maximum Experimental Safe Gap (MESG) value greater than 0.75 mm Examples include carbon monoxide, hydrogen sulphide, ether, cyclopropane, morphline, acetaldehyde, isoprene, and ethylene.
GROUP D	Area contains flammable gas, liquid, or liquid produced vapor with any of the following characteristics: Minimum Ignition Current (MIC) value greater than 0.80 Maximum Experimental Safe Gap (MESG) value greater than 0.75 mm Examples include ammonia, gasoline, butane, benzene, hexane, ethanol, methane, methanol, natural gas, propane, naphtha, and vinyl chloride.
GROUP E	Area contains metal dusts such as magnesium, aluminum, chromium, bronze, titanium, zinc, and other combustible dusts whose abrasiveness, size, and conductivity present a hazard.
GROUP F	Area contains carbonaceous dusts such as charcoal, coal black, carbon black, coke dusts and others that present an explosion hazard.
GROUP G	Area contains combustible dusts not classified in Groups E and F. Examples include starch, grain, flour, wood, plastic, sugar, and chemicals.

NOTE: This post serves only as a guide to acquaint the reader with hazardous area classifications in the USA. It is imperative to discuss your instrumentation, valve, or process equipment requirement with a qualified applications expert prior to installing any electrical device inside of any hazardous area.