During the past few years, end users in the Middle East power generation industry have considered specifying pumps according to American Petroleum Institute (API) standards. The standards, according to the API website, "are designed to assist industry professionals improve the efficiency and cost-effectiveness of their operations, comply with legislative and regulatory requirements, safeguard health, and protect the environment." Typically, the standards require a more robust equipment design.
Two such standards commonly apply to pumps: API Standard 676 for rotary positive displacement pumps and API Standard 610 for centrifugal pumps. As safety standards become more stringent, API standards, or their variations, could more frequently be implemented in industries such as power generation. Understanding what these standards mean and how to apply them can be beneficial for end users.
Refinery Safety Compliance
New refineries in the Middle East have spurred the regional specification of API standards for pumps in the power generation market. The national or private oil companies that build the refineries often construct power plants for the facilities. The oil and gas industry requires API compliance for processing equipment to ensure safety throughout the refinery. This compliance must be based on API industry standards as understood by the equipment manufacturer and the end user—in this case, the oil company.
These oil companies may naturally extend the same API compliance requirements for their hydrocarbon processing equipment in the adjoining power plant. Beyond the pump, API compliance is now being considered or required for the full range of process and auxiliary equipment. API standards are often required for electric motors, valves, tanks and instrumentation. This applies to both new facilities and retrofit operations, particularly if facility ownership has changed and the new owner is committed to API certification.
API compliance may go beyond the power plant. If under the oil company's ownership, other areas of the refinery, including the water treatment facility, may have to meet the standard. As safety standards become more stringent, the application of API standards or their variations could have more international appeal among professionals in the power generation industry.
Defining API Standard 676
This standard is a purchase specification used to facilitate the procurement and manufacturing of specific rotary positive displacement pumps. Like all API standards, 676 was developed to establish a minimum standard for process pumps in mission-critical applications. In oil and gas, these applications could be defined as injection, gathering, transfer and pipeline pumps.
Complete fuel injection skids, such as the one pictured for combustion turbine service in power generation applications, incorporate a high-pressure rotary screw pump. These pumps can be built to meet API specifications should safety standards become more stringent. In power generation, applications include fuel injection, fuel transfer or booster services. The standard helps ensure the integrity of the pump's envelope in the event of an emergency. The most recent version of API Standard 676 (Third Edition, November 2009) specifically states that "... in auxiliary services (e.g., lube oil systems), manufacturer's standard with demonstrated experience is acceptable." In most cases, the API 676 specification would be invoked only when handling fuel.
Safer Pumps
The 676 standard focuses primarily on the pump's external envelope, where safety is a key concern. The customized pump may be of a higher-quality construction than a standard pump. For example, a pump adhering to the standard may employ a steel case and cover instead of cast iron. In case of fire, the cold water used to extinguish the flames could crack a cast-iron case and lead to dangerous leakage. A steel case, on the other hand, could prevent cracks and leaks with the help of hard (silicon and/or tungsten carbide) mechanical seal faces as an additional safeguard.
The standard can require more stringent and detailed documentation. The API specification requires certified material test reports, performance curves and a certificate of compliance. For example, a hydro test for pressure-retaining components would be required for 30 minutes as opposed to the standard five minutes.
Investing in Safety
Customizing the pumps to a standard may include additional costs, but these costs depend on decisions made by the end user. As selections are made within the standard, costs must necessarily increase because of the requirements for more robust materials and increased testing. For example, the steel casing is more expensive than cast-iron.
The best method for managing the cost is that the purchaser ensures the comments and answers to the bulleted paragraphs within the standard are necessary to the service.