As I prepare to head over to Houston today for the Offshore Technology Conference, I see that oil prices have managed to sustain the gains they have made over the month of April. That should help lift everyone’s spirits this week.
Our Emerson oil and gas experts with be there all week in the NRG Center in booth 5817. If you are in the oil and gas business and in the Houston area this week, come by and visit with us. We have complementary OTC Day passes for which you can register.
If you’ll not be able to join us, I’ll be sharing posts over the next few days and capturing some video of our experts for future posts. There are also very active hashtags, #OTC2016, #OTCHouston and the event Twitter account, @OTCHouston where you can follow some of the happenings. Continue Reading ▶
For many applications in the process manufacturing and production industries, solenoid valves are used to “shut off, release, dose, distribute or mix fluids.” Wikipedia defines a solenoid valve as:
…an electromechanically operated valve. The valve is controlled by an electric current through a solenoid: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports. Multiple solenoid valves can be placed together on a manifold.
In a Valve magazine article, Solenoid Pilot Valves for Valve Actuation
, Emerson’s Bill Reeson
defined a “pilot valve” as:
…a three- or four-way solenoid valve that pilots or controls the flow of media, such as air or water, into an actuator, which in turn controls the movement of a valve connected to the actuator. In other words, the pilot valve drives or controls the main process or control valve in a process control system.
This article is a great primer on the terminologies and descriptions used for solenoids. Here’s an example: Continue Reading ▶
Author: Michalle Adkins
In April 2016, the FDA issued Data Integrity and Compliance With CGMP Guidance for Industry. This is on the heels of a lot of related 483s, warning letters, and more severe actions with respect to this issue. There are some interesting things to note from this document.
The FDA has provided this document based on their duty to protect the public health. Generally speaking, data must be reliable and accurate. Pharmaceutical and biotech manufacturers can use risk-based strategies based on process understanding, knowledge management technologies, and business models to prevent and detect integrity issues. Compliant records must keep data from being lost, obliterated, or obscured during the record retention period for that data.
Data Integrity is defined as complete, consistent and accurate data that is attributable, legible, contemporaneously recorded, original or true copy, and accurate, using the acronym ALCOA for easy recall of these components of the definition. All data including metadata, contextual data associated with the data that gives meaning or value to the data, should be maintained according to the record retention policy associated with that data.
This is inclusive of the relationship between data and metadata in a secure and traceable method. An audit trail is a piece of this security aspect, as the audit trail provides the information on “who, what, when and why ” of a record as well as all actions associated with the data including system access as well as creation, modification, renaming, and deleting of files or data in the records. A Quality Unit review of the audit trail on a periodic basis is also recommended. Continue Reading ▶
A question on PID control in the Emerson Exchange 365 community reminded me how good some of the free, online learning tools are available for engineers new to our instrumentation and process automation ranks. The question:
i have a question about PID, about setpoint for one pid from other pid ,,,is possible that these two pid are in deference type? for example :HIC x makes setpoint for FIC x
Community member Youssef.El-Bahtimy responded:
Take a look at this www.controlloopfoundation.com/cascade-control-exercise.aspx
And in books on line the article on PID function block application information
www3.emersonprocess.com/…/c_pid_function_block_application_information.html [Foundation Support login required]
Emerson’s Terry Blevins
and Mark Nixon
developed the Control Loop Foundation learning website in conjunction with the book with the same Control Loop Foundation name
What are great about the site are the workshops, or interactive simulations that you can run to learn the concepts.
Each of these workshops have sections that explain the exercise to be done in the workshop, the process, the workspace where you can simulate the process and control loop responses, a trend chart with the key variables and a video of Terry narrating how to work through the exercise. So specifically for the PID question above about cascade control, here are the links to the tabs:
Continue Reading ▶
In current times where oil supply exceeds demand, storage tanks are filling. A recent Reuters article, Oil glut up close: How Cushing copes with full crude tanks notes:
There may be no better place to witness what a world awash in crude looks like, and the 9 square-mile (23.3 square km)complex seems to bear out oil traders’ fears that the industry is running out of space to contain a historic supply glut that has hammered prices.
Safely storing this inventory is a top priority for tank farms across the supply chain from production to final distribution. In a recent whitepaper, Benefits of Wireless Monitoring of Tank Storage Pressure Safety Valves
, Emerson’s Steve Attri
describes the importance of pressure management in these tanks and in providing feedback to the tank terminal operating staff to help avoid abnormal situations.
The pressure inside these tanks can change based on changes in ambient temperature and tank levels due to filling and removal operations. Pressure is maintained within safe levels by special valves, which sense and react to small pressure changes.
Steve describes the actions of these valves [hyperlinks added]:
The large valve at the center is generally referred to as a pressure vacuum relief valve or PVRV, for short. This device contains weighted pallets which will open and close based on pressure. If the pressure inside the tank rises above the set point, the pressure pallet will open, releasing vapors in order to return the pressure to a safe level. Conversely, if the pressure inside the tank drops below a preset level, the vacuum pallet will move open, bringing air into the tank to return the pressure to a safe level.
The device shown on the left… is called an emergency valve or vent. If an abnormal pressure situation occurs, this vent will quickly relieve tank pressure. Under normal conditions, it should be closed. Note that the small device shown near the front of the tank is a gauge hatch, which is for inspection and gauging purposes.
While these safety devices automatically perform this pressure management function, historically they have been isolated and not connected to feedback any problems back to the operations staff. In fact, a study conducted by Emerson found that: Continue Reading ▶