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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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.

6 Benefits of Using Wireless Networking Systems in Industrial Applications

Wireless technologies offer great value over wired solutions. A reduction in cost is just one of the many benefits of switching to the wireless networking system. There are many benefits, including enhanced management of legacy systems that were previously not possible with a wired networking connection.

Here is an overview of some of the value-added benefits of adopting wireless networking in industrial plants.

1. Reduced Installation Costs - Savings in installation costs is the key benefit of a wireless networking system. The cost of installing a wireless solution is significantly lower as compared to its wired counterpart. Installing a wireless network requires less planning. Extensive surveys are not required to route the wires to control rooms. This reduced installation cost is the main reason industrial setups should consider going wireless instead of having a wired networking system. 
2. Improved Information Accuracy - Adopting wireless networking also results in improved accuracy of information. The wireless system is not prone to interferences. As a result, the system ensures consistent and timely transfer of information from one node to another. 
3. Enhanced Flexibility - Enhanced flexibility is another reason for deploying wireless networking solutions in an industrial setting. Additional points can be awarded easily in an incremental manner. The wireless system can also integrate with legacy systems without any issues. 
4. Operational Efficiencies - Migrating to wireless networking can help in improving operational efficiencies as well. Plant managers can troubleshoot and diagnose issues more easily. The system facilitates predictive maintenance by allowing the monitoring of remote assets. 
5. Human Safety - Another critical factor that should influence the decision to migrate to wireless networking is the human safety factor. Wireless technologies allow safer operations, reducing exposure to harmful environments. For instance, a wireless system can be used in taking a reading and adjusting valves without having to go to the problematic area to take measurements. With wireless networking systems, readings can be taken more frequently that can help in early detection and reduction of possible incidents. 
6. Efficient Information Transfer - Another advantage is that the time required to reach a device is reduced. This results in a more efficient transfer of information between network segments that are geographically separated. The industry wireless networking standards use IP addresses to allow remote access to data from field devices. 

For more information on wireless technologies in industrial settings, contact Miller Energy by visiting https://millerenergy.com or by calling 800-631-5454.

Interface in the Field: Achieving Reliable Interface Measurement to Optimize Process and Increase Uptime

Interface or multiphase level measurements exist throughout the Oil & Gas streams as well as Petrochemical. While level measurement technologies have come a long way in effectively measuring liquids and solids, multiphase level measurement continues to be the biggest challenge and opportunity that exists today to which there is no perfect technology.

However, experience has shown that process optimization and increased uptime can still be achieved in many separator applications through reliable, best-in-class, level technology.

The objective of this paper is to review interface challenges, the current technologies being utilized for interface, field experience in various applications to achieve process optimization and increased uptime, and the future of reliable interface measurement.

DOWNLOAD THE TECHNICAL PAPER HERE

Courtesy of Magnetrol and Miller Energy, Inc.
https://millerenergy.com
800-631-5454

ASCO Express Product Catalog

The ASCO Express program features a range of flow control products and accessories available for shipment the same day you order them. The products listed in this catalog provide the performance required for a variety of system and process applications including boiler, air handling, process control, and water and steam control. The control voltages available for each product are the primary voltages used in industrial and commercial applications today.

Download your copy of the ASCO Express Product Catalog here.

Contact Miller Energy for all your ASCO solenoid valve requirements.

https://millerenergy.com

908-755-6700

Water and Wastewater Treatment Applications for the Magnetrol R82 Pulse Burst Radar Transmitters

The Magnetrol R82 Pulse Burst Radar transmitter performs across a wide range of applications. The R82 is designed to provide radar reliable process measurement in challenging, vapor saturated environments, at the cost of what you pay for an ultrasonic device. For water treatment, the Magnetrol R82 Pulse Burst Radar transmitter provides continuous level measurement at the lift station and coagulant feed tanks, in settling tanks during clarification, in polymer, filter, and lime slurry tanks during filtration, and for open atmosphere water reservoirs where the control technology must withstand punishing weather conditions.  In wastewater facilities, the R82 radar can control level at the lift station pump, open channel flow and screening system, monitor feed tanks containing chemical coagulants oxidants and phosphorous precipitation, measure splitter box in clarifier levels, control corrosion inhibitors, manage pH adjustment, mixed liquor and secondary clarifier levels, as well as activated sludge and digester level control.

Miller Energy, Inc.
https://millerenergy.com

How Do Pilot Operated Tank Relief Valves Work?

Storage tanks become pressurized when liquid is pumped in and compresses the existing tank vapor. Tanks also become pressurized due to increasing ambient temperatures, which cause the tank vapor to expand. To mitigate damage from these expanding tank vapors, pressure relief valves are installed on tanks to prevent structural damage resulting from over-pressure.

Here is an excellent animation, courtesy of Cashco, that shows how a pilot operated relief vent protects a storage tank from over pressurizing during a pump-in situation or during thermal heating conditions.

For more information on tank relief valves, contact Miller Energy at www.millerenergy.com or by calling 908-755-6700.

Thermal Mass Flow Meter Q&A From Magnetrol

Thermatel® thermal mass flow meter
Courtesy Magnetrol®

Sometimes you discover that others do something better than you. When that happens, watch and listen.

Tom Kemme, from Magnetrol®, expertly fielded some questions about thermal mass flow meters in a recent blog post. Mr. Kemme's responses were so useful and clear that I decided, with all the credit flowing his way, to share them here for those of you that may not closely follow the Magnetrol® Blog.

Question: What is the difference between the flow units Nm3/h, Sm3/h, and actual m3/h?

Answer: Actual m3/h is a flow rate at operating temperature and pressure. Normal or standard m3/h (Nm3/h = Sm3/h) is a flow rate at standard temperature and pressure (STP). I tend to reference the natural gas industry, where it is not possible to compare flow rates at every operating condition, so it is preferable to reference all flow rates back to a set of base conditions, such as 60°F and 1 atm. STP is not universal so it may be unique based on the region or industry.

Most flow meters output a flow rate at operating conditions and need to correct this measurement. This may be accomplished with a multivariable transmitter or external to the device. A few examples that do not need to correct the measurement are thermal mass flow meters, such as the ones produced by MAGNETROL, and Coriolis flow meters.

Question: Do you have any certified failure rate data on your units to perform an SIL verification?

Answer: A Failure Modes, Effects, and Diagnostics Analysis (FMEDA) is completed during development to determine failure rates and Safe Failure Fraction (SFF). The SFF is utilized to determine Safety Integrity Level (SIL), which is often the published value.

Question: What should my meter be reading with no air flow in the pipe?

Answer: At zero flow and a dry pipe, a thermal mass flow meter should measure zero. Different thermal meters may have varying stability at no flow due to differences in operation.

There are two different types of operation: constant temperature (CT) and constant power (CP). CT devices start with a low power and this power increases with the flow rate to maintain the constant temperature difference (ΔT) between the RTDs. CP devices start with a high ΔT between RTDs at low flow and the ΔT decreases as the flow rate increases. CP may lack stability at zero flow due to possible convection currents associated with the high ΔT. CT will hold zero better, particularly devices that add less heat. For example, the maximum surface temperature of a TA2 probe is 4 C above process temperature. This is extremely low heat, eliminating convection currents due to the sensor. Convection currents could also occur through the pipe due to temperature variations.

It is also possible for a thermal meter to measure above zero during a no flow condition when there is pressure buildup in the line (typically a valve closed downstream). There may be low flow cutoff settings that can be changed to ignore nuisance measurements.

You can easily tap into Magnetrol® expertise to solve your flow measurement challenges. Reach out to a product specialist and combine your process knowledge with their flow measurement expertise to develop effective solutions.

Dynamic Compensation for Static Pressure Effects in Differential Pressure Measurement

DPharp Gauge Pressure Transmitter
Courtesy Yokogawa

Attaining the best available performance and accuracy from any measuring device utilized in an industrial process is always advantageous. The scale of most industrial processes is such that even small inaccuracies in process measurement produce financially tangible impact. Differential pressure measurement, with wide application in the industrial process sphere, can be improved with the addition of a means to compensate for the real world effects of static pressure upon instrument performance.

Yokogawa Corporation has developed a means to dynamically compensate for static pressure effects in field measurements. The brief technical presentation below will help you understand how static pressure effects can impact your field measurements, as well as how Yokogawa’s Real-time Dynamic Compensation works to offset its impact.

More detailed product and application information is available from your Yokogawa specialist.

Dynamic Compensation for Static Pressure Effects in Differential Pressure Measurement from Miller Energy, Inc.

Diaphragm Pressure Gauges for Industrial Process Measurement

Example of a diaphragm pressure gauge
Courtesy Wika

Diaphragm pressure gauges, like every device and instrument intended for use in industrial process measurement and control, have their own set of attributes making them an advantageous choice for some range of applications. Silvia Weber, product manager at Wika, a globally recognized leader in the field of pressure and temperature gauges, wrote an article for Process Worldwide (process-worldwide.com/) about diaphragm pressure gauges.

The article is included below and provides a comparison of the differences between Bourdon tube and diaphragm operating mechanisms, focusing on design and operational features of diaphragm pressure gauges and the range of application criteria for which they may be the best choice.

Pressure gauges are utilized in most operations where fluids are moved through a system. Gauges, though mechanical in operation, remain a mainstay of fluid operations because of their reliability, local display, ruggedness, and lack of reliance on electric power for operation. There are countless pressure gauge configurations to suit every application. Specifying the best gauge configuration for an application is accomplished by combining your process knowledge with the application expertise of a product specialist.

Applying Diaphragm pressure gauges in industrial settings from Miller Energy, Inc.

Protect Valuable Pressure Gauges and Transmitters With a Pressure Limiting Valve

Pressure limiting valve provides gauge
or transmitter protection from spikes
Courtesy Mid-West Instruments

Pressure gauges and transmitters, commonly found in fluid process control operations, are vulnerable to damage from transient spikes in system pressure that may range beyond the instrument's working range. These pressure spikes can impact instrument calibration, or even render the instrument or gauge inoperative. The cost of replacing gauges or transmitters is substantial enough to warrant the use of protective devices to prevent exposure to pressure spikes.

Mid-West Instruments manufactures a line of pressure limiting valves specifically intended for use with pressure gauges and transmitters. The Model 200 pressure limiting valve prevents instrument over-range and has an adjustable needle valve to dampen pulsation. The valve and be used with all types of instruments and pressure gauges, is suitable for mounting in any position, and is available in a range of materials for body and seals.

The document below provides more product detail, as well as installation and setup instructions. Providing a useful measure of protection for pressure gauges and transmitters is a simple operation. Reach out to product application specialists for help in formulating effective solutions.

Pressure limiting valves for transmitter and gauge protection from Miller Energy, Inc.

Industrial Process Gauges - New Product Guide

One of the many pressure gauge versions
employed throughout industry
Courtesy Ametek - U.S. Gauge

Even with the large growth in the use of electronic measurement instruments throughout the process control sphere, mechanical gauges and indicators remain an important part of process measurement and control operations.

A broad line of industrial gauges and diaphragm seals is available from U.S. Gauge. The company has consolidated its offering into a product guide that provides simple and quick reference to the various product series.

For pressure:

• Process Gauges
• Liquid Filled Gauges
• Test Gauges
• General Equipment Gauges
• Special Application Gauges

For temperature:

• Adjustable Bimetallic Thermometers
• Thermowells
• Industrial Bimetallic Thermometers
• Multi-Angle Industrial Thermometers
• Digital Thermometers
• Glass Tube Thermometers

The product guide also includes diaphragm seals and a range of electronic indicators, as well.

The guide illustrates gauges for every industrial application. Share your process measurement and control challenges with product application specialists, combining your process knowledge with their product application expertise to develop effective solutions.

Product guide for industrial gauges from Ametek U.S. Gauge from Miller Energy, Inc.

Basic Guide to Understanding Pressure

One style of absolute pressure transmitter
Courtesy Yokogawa

The impact of pressure on industrial processes would be difficult to understate. Pressure is an element of process control that can affect performance and safety. Understanding pressure concepts and how to effectively measure pressure within a process are key to any operator's success.

Yokogawa, a globally recognized leader in process measurement and control, has made available a handbook on pressure that covers a range of useful topics. The content starts with the very basic concepts and moves quickly to practical subjects related to process measurement and control.

The handbook will prove useful to readers at all levels of expertise. Share your process measurement challenges with application specialists, combining your process knowledge with their product application expertise to develop effective solutions.

Pressure Handbook for Industrial Process Measurement and Control from Miller Energy, Inc.