A smooth process

By Jari Kirmanen, Product Manager at Metso Automation

Metso Automation’s Jari Kirmanen lifts the lid on new developments and technologies in process control values.

O&G. What are the key trends in technology development that you see in process control valves for the oil and gas industry?
Jari Kirmanen. The biggest revolution in control valve technology occurred when intelligent, digital positioners entered the market during the 1990s. Since then, valves equipped with intelligent positioners, like the Neles ND9000, have become the de facto solution for process control. In addition to easier commissioning and high performance, the best of these intelligent positioners provide on-line diagnostic features.

Most installed intelligent positioners use HART-technology, but recently fieldbuses have established a firm foothold in the oil and gas industry. Intelligent control valves provide more solid integration of valves into the DCS, but they do require more training than conventional technology. While this clearly presents a challenge, it also offers an opportunity to gain major benefits. Hence major oil and gas companies have added intelligent technology to their existing valve strategies.

The ever-increasing emphasis on environmental issues has meant that oil and gas companies are paying increased attention to emissions coming from control valves. This is one of the trends that make rotary valves more attractive, because rotary valves typically have lower gland emissions than globe valves. Valve vendors are required to develop products that can handle demanding fluids, because more heavy oil is now being converted to valuable products and the sand content of crude is higher. New innovations, which combine conventional globe and rotary valve technologies, have been launched. Average line sizes have increased, and this factor together with extreme temperatures have made metal-seated butterfly valves more attractive, for example in the LNG industry in Middle East.

O&G. What about safety valves?
JK. Safety standards IEC 60508/61511 and ISA 84 are nowadays widely used in the oil and gas industry. Third party certifications of well-known authorities, such as TUV or Lloyds, are used to verify the reliability level of safety devices and valves. Due to some catastrophic accidents in the process industry, the importance of safety systems and SIL-rated devices including valve controllers has even increased. The main driver for the development is simply to verify the safety function availability whenever it is needed. The standards require safety valve operation to be verified at certain time intervals; and to do this, valve vendors have developed automatic partial stroking devices, which make it possible to carry out valve testing during run-time and provide the opportunity to improve probability on demand value. Neles ValvGuard was the first intelligent safety valve controller designed for ESD services. Intelligent safety controllers, like positioners, can be integrated into safety and automation systems, which simplifies the control and diagnosis of safety devices. Metal-seated ball valves with piston-type actuators equipped with an intelligent safety valve controller have proven to be the most reliable solution for safety applications.

O&G. You mentioned on-line advanced diagnostic. What do you mean by that?
JK. Off-line diagnostics mean that the diagnoses are only carried out during process off-time, which is not the most efficient method. It may create unnecessary maintenance activities or lack of spare parts because analysis is only done during a shutdown period. By contrast, with the help of on-line diagnostics, valve performance can be detected during process on-time. This provides opportunities to decide on maintenance activities prior to the shutdown period. One of the biggest advantages of predictive maintenance using on-line diagnostics is that you can optimise maintenance activities and sometimes avoid unnecessary maintenance.

The best technology available to gain the benefits of on-line diagnostics is FDT/DTM. This technology is supported by various types of company – from valve and instrument vendors to DCS companies and end users. FDT/DTM provides an open technology, which enables users to take advantage of all the benefits of demanding diagnostic features for complex devices like process control, safety and automated on/off valves, and all this can be integrated in the vendor’s independent asset management systems.

Jari Kirmanen is Product Manager of Neles Product Line at Metso Automation. Kirmanen, who holds a MSc in Applied Physics, has 14 years of experience in the valve business. During his career, he has developed expertise in valve sizing, noise and control technologies together with applications. He is Finnish national representative on the International Standardisation Committee for control valves (IEC SC 65B/WG9), and member of the ISA.