Monday, July 15, 2019

Reducing Material Waste in Flexible Pet (Polyethylene Terephthalate) Production

Reducing Material Waste in Flexible Pet

Polyester is very popular because it is a light, soft, flexible, low-maintenance material that keeps you warm. Making it this way poses diverse challenges to PET producers.


A chemical plant specializing in producing PET was looking for a solution to reduce the waste resulting from product variance. The factory produces 25,000 tons of polyester annually, which is then provided to other manufacturers to produce a vast range of end products.

SITRANS FC430
The SITRANS FC430
monitors the glycol flow.
This vast range requires different PET grades, which are achieved by slight variations in the synthesis procedures. In order to investigate possible options to upgrade their primary processing, understanding the complete process is vital. In the case of PET production, this process starts with mixing three key ingredients – PTA and IPA powder along with glycol liquid – in specific ratios to make a paste.

These source materials are stored in stainless steel bins with a volume of 2649 ft3. Rotary feeders move the mate- rial from these bins to a batching vessel along with glycol to make the polyester paste. The batching vessel is agitated to ensure that the mixture is always consistent. Monitoring tank levels, precisely controlling the dosing, the efficient use of raw materials and ensuring a consistent mix are the key parameters
SIWAREX WP251
SIWAREX WP251
when it comes to improving the primary processing. When Siemens designed a new system for the chemical plant from the bottom up, the Siemens S7-1200 PLC controller was the first product that was installed to set up a compact and flexible automation solution, which keeps track of the key parameters and the process efficiency.

Don’t get mixed up during mixing

Each raw material bin is mounted on Siwarex WL280 ring torsion load cells to achieve optimum weighing accuracy. These load cells are connected to two Siwarex WP251 weighing modules, which are specifically designed for batching applications. The advantages of this solution are that the WL280 load cells feature a C3 class rating for accuracy as well as an IP68 rating for protection against dust and direct high-pressure cleaning – ideal for handling powder materials such as PTA. In connection with the Siwarex WP251, a customer-specific application was engineered with a resolution of up to +/- 4 million parts.

SITRANS TS500
SITRANS TS500
The glycol as the liquid component in this process is monitored by a Sitrans FC430 coriolis mass flowmeter providing a 4-20 mA output, which varies based on the flow rate of the material. This signal is fed into an analog S7-1200 input module. A Sipart PS2 positioner controls the valves to regulate the flow rate. In such flexible processes as this one, the operator individually sets the setpoint for total production. At the field level, this flexibility is achieved using Sinamics variable frequency drives, which independently adjust the flow rate of each material. To close the loop, the discharge rates from the raw material bins are monitored by the WP251. The output is then processed by the S7-1200 controller, sent through an analog module to control the Sipart PS2 positioner – which in turn allows more or less glycol to flow into the batching vessel. The downstream Sitrans FC430 flow meter additionally verifies the flow rate to ensure a high-quality mix.

How powder and liquid become PET

Pointek CLS200
Pointek CLS200
The temperature of the paste is another crucial factor when it comes to producing high-quality PET. If the agitation causes too much heat, the whole mixture could be lost, causing unwanted waste. In this configuration, a TS500 controls the temperature to the optimum level. To further cut down on product loss, a Pointek CLS200 capacitance- based switch acts as a backup device to ensure that the material discharges completely, and does not build up or overflow. Its high frequency oscillation makes it insensitive to product buildup, therefore guaranteeing reliable level monitoring in the PET paste vessel. For integrated control and alarm management, the level switch is connected to the S7-1200 controller. With 13 sensors, 2 VFDs, 3 geared motors, 4 modules and 1 HMI installed and connected to the control system, the plant managers reap the benefits of a comprehensive portfolio from one supplier. The new equipment is reliable and efficient and – together with the DCS solution – offers excellent process and data control.

Less material waste and reduced downtimes

SIPART PS2
SIPART PS2
Where did this leave the chemical company? After the equipment had been running for 3 months, the first estimates were made as to whether the initial goals of reduced waste and increased efficiency had been met. The result: plant efficiency had increased by 27 % due to the reduced material waste and product loss. Further, the more reliable process measurements and diagnostics help the company to service their equipment on a preventive basis instead of a reactive one, resulting in reduced downtimes and in- creased reliability.

Simplified diagram
Simplified diagram showing the customer’s process.
So the next time, you put on your running gear, take a sip out of a plastic bottle or attach your safety belt, maybe you will remember the effort that goes into producing the PET that is needed to manufacture these types of products. By the way – they have another important characteristic in common as they can be completely recycled.






Ives Equipment
877-768-1600
https://ivesequipment.com

Sunday, June 30, 2019

Oil & Gas and Power Grids Have New "Cause for Concern" from Hackers

A report released in June, from the security firm Dragos, describes a worrisome development by a hacker group named, “Xenotime” and at least two dangerous oil and gas intrusions and ongoing reconnaissance on United States power grids.

Multiple ICS (Industrial Control Sectors) sectors now face the XENOTIME threat; this means individual verticals – such as oil and gas, manufacturing, or electric – cannot ignore threats to other ICS entities because they are not specifically targeted.


The Dragos researchers have termed this threat proliferation as the world’s most dangerous cyberthreat since an event in 2017 where Xenotime had caused a serious operational outage at a crucial site in the Middle East.

The fact that concerns cybersecurity experts the most is that this hacking attack was a malware that chose to target the facility safety processes (SIS – safety instrumentation system).

For example, when temperatures in a reactor increase to an unsafe level, an SIS will automatically start a cooling process or immediately close a valve to prevent a safety accident. The SIS safety stems are both hardware and software that combine to protect facilities from life threatening accidents.

At this point, no one is sure who is behind Xenotime. Russia has been connected to one of the critical infrastructure attacks in the Ukraine.  That attack was viewed to be the first hacker related power grid outage.

This is a “Cause for Concern” post that was published by Dragos on June 14, 2019.

“While none of the electric utility targeting events has resulted in a known, successful intrusion into victim organizations to date, the persistent attempts, and expansion in scope is cause for definite concern. XENOTIME has successfully compromised several oil and gas environments which demonstrates its ability to do so in other verticals. Specifically, XENOTIME remains one of only four threats (along with ELECTRUM, Sandworm, and the entities responsible for Stuxnet) to execute a deliberate disruptive or destructive attack.

XENOTIME is the only known entity to specifically target safety instrumented systems (SIS) for disruptive or destructive purposes. Electric utility environments are significantly different from oil and gas operations in several aspects, but electric operations still have safety and protection equipment that could be targeted with similar tradecraft. XENOTIME expressing consistent, direct interest in electric utility operations is a cause for deep concern given this adversary’s willingness to compromise process safety – and thus integrity – to fulfill its mission.

XENOTIME’s expansion to another industry vertical is emblematic of an increasingly hostile industrial threat landscape. Most observed XENOTIME activity focuses on initial information gathering and access operations necessary for follow-on ICS intrusion operations. As seen in long-running state-sponsored intrusions into US, UK, and other electric infrastructure, entities are increasingly interested in the fundamentals of ICS operations and displaying all the hallmarks associated with information and access acquisition necessary to conduct future attacks. While Dragos sees no evidence at this time indicating that XENOTIME (or any other activity group, such as ELECTRUM or ALLANITE) is capable of executing a prolonged disruptive or destructive event on electric utility operations, observed activity strongly signals adversary interest in meeting the prerequisites for doing so.”

Thursday, June 27, 2019

NH3 Slip Measurement in the Fluidized-Bed Catalytic Cracking Process


AN APPLICATION NOTE FROM SIEMENS PROCESS ANALYTICS

Fluidized-Bed Catalytic Cracking (FCC) is the most important and widely used refinery process for converting low value heavy oils into more valuable gasoline and lighter products.

The typical FCC process will convert 75% or more of the heavy oils to gasoline and lighter products. Originally, chemical cracking was accomplished by heating the oil to super high temperatures but the catalytic process has almost completely replaced thermal cracking.

The cracking process produces carbon (coke) which remains on the catalyst particle and rapidly lowers its activity. To maintain the catalyst activity at a usable level, it is necessary to regenerate the catalyst by burning off the coke with air. As a result, the catalyst is continuously moved from reactor to regenerator and back to reactor.


Contact Ives Equipment for more information. Call (877) 768-1600 or visit https://ivesequipment.com.

Saturday, June 15, 2019

Calibration Services for Process Instrumentation


Measuring, positioning, recording, and controlling are important parameters in all industries processes. That’s why process instruments need to deliver the highest levels of precision and reliability.

Today calibration measuring devices is an important production and competitive activity due to steadily increasing demands on reliability, availability and performance.

Off-site Calibration Services

Siemens offers factory calibration services for Pressure, Temperature and Flowmeters from both our own and other manufacturers.

On-site Calibration Services

Siemens offers on-site calibrations for Pressure, Temperature and Belt scale of our own products as well as those of other manufacturers.

This video presents the viewer with explanations and concepts for the following:

  • The Siemens Process Instrument Services overview.
  • A description of field instrument technologies.
  • What calibration means.
  • Reasons for calibrating field devices.
  • The importance of calibration and verification.
  • What traceability means.
  • Why accreditation is needed.
  • The Siemens Factory Calibration process.
  • The Siemens On-site Calibration process.
  • What verification means.
  • Reasons for verification.
  • The Siemens On-site Verification process.

For more information, contact Ives Equipment:
(877) 768-1600
https://ivesequipment.com

Wednesday, May 29, 2019

What Are Pneumatic Actuators?

rack and pinion actuator
Internal view of rack and pinion actuator
(Flowserve Worcester)
Pneumatic valve actuators are used in extreme conditions in many industries such as oil and gas, chemical, water and wastewater, bulk storage, pulp & paper, and power generation. These devices are used in a multitude of valve control processes for regulation (or cessation) of flow, controlling pressure and adjusting level.  Due to their reliability and simplicity, pneumatic actuators are one of the most popular types of actuators used in industry today.

Pneumatic valve actuators work by conversion of air pressure into motion. The device applies a force of air to a diaphragm, rotary vane, or piston that is attached to the actuator shaft, which is then mechanically connected to the stem of the valve or damper. Depending on the type, pneumatic actuators produce either linear or rotary motion. 

ACTUATOR ACTION - SPRING RETURN OR DOUBLE ACTING

Spring Return — Pneumatic actuators with spring return design have air supplied from one side. The spring on the opposite side is responsible for the motion. With this design, air compression moves the opens or shuts the valves while the spring is responsible for the opposite motion. 

Double Acting  — Double acting actuators have air fed on both sides of a piston. The pressure on one side is higher as compared to the other that results in the required in movement. Air is used to open and close the valves.  

Diaphragm actuator
Diaphragm actuator
(Samson)
PNEUMATIC ACTUATOR DESIGNS

Diaphragm Actuators — Diaphragm actuators work by applying pressure to a thin membrane or diaphragm. 

Piston Actuators — Piston actuators apply compress air to a piston that is within a cylinder. Air is fed into a chamber that moves the piston in one direction. The piston moves in the opposite direction when air pressure is removed (spring assisted) or directed to the other side (double acting). 

Rack and Pinion — Rack and pinion actuators produce rotation by applying pressure to pistons with gears that turn a pinion gear. Rack and pinion actuators can be spring return or double acting. They are valued because of their compact size and versatility.

Scotch Yoke — A scotch-yoke actuator contains a piston, yoke, connecting shaft, and rotary pin.
Scotch yoke actuator
Scotch yoke actuator
(Samson)
They can be direct acting or spring return. They are capable of providing very high torque outputs and are generally used on larger valves. Scotch yoke actuators can be powered by air or process gas.

Rotary Vane —Vane actuators use a mechanical vane, connected to a shaft, that separates a circular shaped body in two "clamshell" halves. The vane moves in response to the differential pressure inside the actuator body, turning the shaft clockwise or counter-clockwise in response to the pressure differential. External springs units are available for spring return models.

BENEFITS OF PNEUMATIC ACTUATORS

The use of compressed air (typically found in all industrial facilities) as the power source is the prime advantage for the use of pneumatic actuators. Additionally, pneumatic actuators have an advantage in suitability for different environments and can be used in extremes temperatures. They are preferred over electrical actuators in explosive, flammable and other hazardous areas because they do not require electricity (a possible ignition source) to operate. They do not create electrical fields or electrical noise since there is no electrical motor. Pneumatic valve actuators are faster opening and closing compared to their electric counterparts. Finally, they are low cost, lightweight, durable, require little maintenance (depending on quality) and there are a myriad of positioning controls, speed controls, and communications devices available for tailoring the actuator to the application.

DRAWBACKS OF PNEUMATIC ACTUATORS

While compressed air is the main reason for using pneumatic actuators, it can also be considered a drawback. For instance, pneumatic actuators can perform poorly when the air supply source is located at a distance, resulting in lag and slow response. Another drawback of pneumatic actuators is the additional cost for the compressed air system due to the requirement of dust filters and moisture removing dryers. These are required to ensure clean air is fed into the system.

APPLYING PNEUMATIC ACTUATORS

There are many aspects to the proper, safe, and efficient application of pneumatic actuators to valves and dampers. Sizing the power output (torque) being paramount. All valves and dampers have unique torque requirements. You must consider a threshold force for opening (breakaway), as the valve continues to move to its open or closed position, and then for seating. Matching the actuators to the valve type, and operating conditions is critical. Published torque curves must be reviewed and understood. Too little torque and the vale will not respond. Too much torque increases cost and can damage the valve. Spring return adds to this complexity. Considering all this, it is strongly suggested you always discuss any valve actuation requirement with an experienced applications expert. They will ensure the proper, safe, and cost effective mating of pneumatic actuator to valve or damper.