Last updateThu, 20 Sep 2018 3pm



Preparing for a Plant Outage

Preparing for a Plant OutageIt is well known that effective planning can save time and curtail expenses when production and utility plant areas prepare for upcoming maintenance turnarounds, outages, and shut-downs. Such planning is also a key component to effective management of both the internal maintenance employees and externally contracted technicians that perform the work. Since manpower resources make up a large portion of the total expenses associated with any outage, organizing those resources is as critical as organizing the process itself.

In many cases the outage is part of an existing plant preventive maintenance (PM) program: critical valves within the plant’s valve population have already been identified or repairs have already been scheduled. That PM program may depend on use of an existing computerized maintenance management system (CMMS), which can help when scheduling work to be performed and when reconciling a list of poorly performing valves already identified.

Oxygen Cleaning: A Validated Process is Critical for Safety

Oxygen Cleaning A Validated Process is Critical for SafetyIndustrial oxygen is used for many purposes: in a basic oxygen furnace for making steel, water pollution countermeasures, including sewage treatment, habitability and superfund site rehabilitation, and chemical processes such as production of vinyl chloride, nitric acid, epoxyethane and hydrogen peroxide. It is also used for medical treatment, life support in harsh environments and industrial gasses for welding and other processes.

The production of oxygen has risen from approximatey 470 billion cubic feet in 1991 to over 1.5 trillion cubic feet in the U.S. and more than 4 trillion cubic feet globally in 2014.

PWHT of Thick Ferrous Valve Castings

PWHT of Thick Ferrous Valve CastingsCastings made from many different ferrous alloys are produced for many industries, including valves. This article provides a quick review of phase transformations and the basics of heat treatment. Carbon, alloy and martensitic steels are typically used in valves and four important factors are addressed:

  1. Ensuring the casting and/or weld is at temperature
  2. The importance of time at temperature during different cycles
  3. Lag time between oven temperature casting surface vs. centerline of thick section temperature
  4. The need to avoid temper embrittlement

Valves in a Cement Slurry Line

Valves in a Cement Slurry LineBasically everywhere you look in modern society, you see something made of concrete. Often we see trucks traveling down the road, drums spinning to keep the cargo mixing on their way to a job site in a subdivision or business park. It’s so common, in fact, that most people barely give it a second thought, but the process that turns limestone into towers of concrete and steel is one that creates its own challenges for valves in a cement plant, especially those in the slurry line.

One of the largest cement companies in the world is Lafarge, which produces cement for residential and commercial construction and for oil wells. Ed Kunkel worked for Lafarge at its plant in southwestern Ontario for more than 30 years, and he provided much of the process line and valve specification information for this article. We also spoke Ed Holtgraver of QTRCO, Inc., Tomball, TX, who provided us with additional information about valves and actuation.

Inexpensive Safe Water Tapped by Correcting Control Valve Output

Inexpensive Safe Water Tapped by Correcting Control Valve OutputThe error output from a control valve can come from a variety of sources: uncontrolled input pressure, uncontrolled input flow rate, inaccurate orifice size or turbulent flow through the system which causes irregularity of flow rates through the system. Inaccurate orifice size can result from dirt or scale in the system or from the operator having insufficient ability to set the orifice size. A common bathroom faucet, for example, is very difficult to set to an exact size due to imprecise setting mechanisms and also varying amounts of washer compression.

While progress has been made in creating valves with accurate orifice sizes, many control valves still require electronic control loops to ensure outputs are within desired limits. However, use of these electronic controls is not always practical. They can be expensive. They need regulated electricity which is not always available and which is often inconvenient to connect with. Electronic controls can also be vulnerable to damage, which not only reduces their lifespan, it reduces their reliability. They can require training to use as well. Particularly in foreign, underdeveloped markets or for some home markets, these issues can prohibit use of electronic controls for some applications.

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