On the selection of pneumatic and electric instruments in petrochemical industries
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I work in the field of automated maintenance for oil pipelines; the actuators used on our company’s pipelines are either electric or pilot-operated. Are there any electric actuators used in the new projects in the chemical industry? Pneumatic still?
It is said that electric versions are used by some small factories that do not have a air purification system. Most of our factory’s equipment is pneumatic.
Generally, chemical companies choose pneumatic actuators, not only because of the need for clean air but mainly due to explosion-proof requirements. In flammable and explosive environments, electric actuators are not suitable; in power plants or other situations where no explosion-proof requirements apply, electric actuators are more commonly used
Large-scale projects generally also use electric actuators, but in small numbers; pneumatic actuators are still the predominant choice, as they offer safety and explosion protection, are relatively inexpensive, and have a simple structure that makes them easy to maintain.
I work in automatic control design. In large petrochemical plants, pneumatic actuators are widely used. However, it can be difficult to obtain the necessary instrument air; therefore, electric actuators are used in areas such as tank farms. In a power plant project I worked on previously, there wasn’t enough instrument air for the entire plant, so electric actuators were used instead
We use wind-powered systems here more often, as they are convenient for maintenance and safe as well as easy to use
From a safety perspective, electric power has a major advantage: in the event of a power outage, a backup diesel generator is available to provide power and keep things running. Pneumatic systems can’t do that; once the air supply stops, it becomes difficult to move. Here, in our fire protection system, there are over 100 electric valves in total.
From an explosion-proof perspective, the explosion-proof ratings of many electric actuators available today are also sufficient to meet the requirements of explosive hazard areas.