Operator opening

Bolted joints are friendlier than quick-release couplings. The former are usually dismantled by a fitter after issue of a permit to work. One person prepares the equipment and another person opens it up the issue of the permit provides an opportunity to check that the correct precautions have been taken. In addition, if the joints are unbolted correctly, any trapped pressure is immediately apparent and the joint can be remade or the pressure allowed to blow off. In contrast, many accidents have occurred because operators opened up equipment which was under pressure, without independent consideration of the hazards, using quick-release couphngs. There are, however, designs of quick-release couphngs which give the operator a second chance. 

Runaway reaction Interlock manway with vessel pressure with manway, Design system for closed manual operation open—foam out (can be acid based), operator contacted by process materials. CCPS G-22 CCPS G-23 CCPS G-29 Fisher 1990 ISAS84.01... 

The expander is now ready to be put into operation. Open the compressor inlet valve and expander discharge valve simultaneously. Then open the compressor discharge valve. Make sure the variable nozzles are in the closed position. Push the start button on the control panel to open the inlet shutdown valve. 

When a pump has a motor drive, the process engineer must verify that the motor will not overload from extreme process changes. The horsepower for a centrifugal pump increases with flow. If the control valve in the discharge line fully opens or an operator opens the control valve bypass, the pump will tend to run out on its curve, giving more flow and requiring more... 

Whenever possible, external relief valves should be furnished. On the larger systems, this is mandatory. Internal relief valves will lead to pre mature pump failure if allowed to operate open for more than a few minutes, since the hot oil is returned directly to the suction. An upset period, the time when a pump may open the relief, is probably not the time when an operator would detect the open valve and shut the pump down to r< t the valve. 

Blocked Discharge. It is assumed that all outlets from the vessel are shut in and the total inlet flow stream (gas and liquids) must flow out through the relief valve. This condition could occur, for example, if the equipment has been shut in and isolated and the operator opens the inlet before opening the outlet valves. 

A similar incident to that at Feyzin occurred at this refinery in Brazil in 1972. According to press reports, the relief valve failed to open when the pressure in an LPG sphere rose. To try to reduce the pressure, the operators opened the drain valve. Little water came out, and the LPG that followed it caused the valve to freeze, and the flow could not be stopped. There was only one drain valve. The LPG ignited, the vessel BLEVEd, and 37 people were killed. 

One day the inevitable happened. Having defeated the interlock, an operator opened a drain valve in error instead of a transfer valve. 

In canned pumps the rotor (the moving part of the electric motor) is immersed in the process liquid the stator (the fixed part of the electric motor) is separated from the rotor by a stainless steel can. If there is a hole in the can, process liquid can get into the stator compartment. A pressure relief plug is therefore fitted to the compartment and should be used before the compartment is opened for work on the stator. One day, an operator opened the pump without using the pressure relief plug. There was a hole in the can which had caused a pressure build-up in the stator compartment. When the cover was unbolted, it was blown off and hit a scaffold 6 feet above. On the way up it hit a man on the knee and the escaping vapor caused eye irritation. The worker was not familiar with canned pumps and did not realize that the pressure relief plug should be used before opening the compartment. 

In most air and gas drilling operations, open-hole well completions are common. This type of completion is consistent with low pore pressure and the desire to avoid formation damage. It is often used for gas wells where nitrogen foam fracturing stimulation is necessary to provide production. In oil wells drilled with natural gas as the drilling fluid, the well is often an open hole completed with a screen set on a liner hanger to control sand influx to the well. 

Figure 5.8. Effect of catalyst-electrode potential UWR on the work function O of the gas exposed catalyst-electrode surface (a) Pt/YSZ, T = 300°C (squares), Pt/p"-Al203, T = 240°C (circles), filled symbols closed-circuit operation, open symbols open-circuit operation, 02, C2H4/02 and NH3/02 mixtures.2-26 (b) Ag/YSZ, T - 547°C,24 (c) Pt/p"-Al203, T = 200°C,25 (d) Ir02/YSZ, T = 330°C, air,27 (e) Ir02/YSZ, T = 380°C, po2 = 15 kPa, pC2H4 = 5 10 2 kPa,27 (f) Ir02/ p"-Al203, T = 330°C, air.27...

It is easy to improperly design a steam trap. The design must work for two circumstances and often a designer will check only one of these. The circumstance often overlooked is as follows On startup or upset, the steam control valve can open wide so that the steam chest pressure (assume for this discussion that we are speaking of a reboiler) rises to full steam line pressure. At a time like this, the steam trap downstream pressure can be atmospheric due to process variations or the operators opening the trap discharge to atmosphere in an attempt to get it working. 

On the surface, the move seemed quite innocent. Having gone into the government, Krauch moved to where the government was. His new office was called Vermittlungstelle Wehrmacht, which meant "Army Liaison." Had the office operated openly, few suspicions would have been aroused, for part of Farben s business had always come from supplying armies with munitions components. 

Closed ends normally applies to reactor operation. Open ends may be used with tracer studies when tracer is injected and sampled some distances from the ends of the vessel. The figures show these two cases. 

Open during recharging operation, closed during booster operation Open during booster operation, closed during recharging operation... 

An example of a causal factor chart for a relatively simple incident is shown in Figure 9-8. In this example, there are two redundant pumps, one of which is required to supply feed to a reactor downstream. The operator is requested to change-over operation from Pump A, which is running, to Pump B, which was previously shutdown. Instead of opening Pump B suction valve, the operator opens the wrong valve, causing the Reactor to trip on low flow detection. 

In another example, in 2004 a judge ordered the USDA to identify the Hawaiian locations of four companies operating open air test sites for bio-pharmaceutical crops. The order had been earlier denied as it was considered to contain confidential business information protected from disclosure under federal law. Public disclosure could result in the destruction of the fields by anti-GM extremists. Vandalism such as this does little to protect the health of the public or the environment. Rather, it causes the dispersal of transgenic crops into the environment, thus creating the very harm feared by these adversaries (Jaffe, 2004a). 

Use closed-loop systems, which might be installed down-mine , or within settlement basins at a minewater treatment plant. Here the collector fluid circulates in a closed-loop and never comes into contact with the mine water. Likewise, mine water never enters the heat pump or heat exchanger elements. The problem is thus wholly averted, although there are limitations in capacity to closed-loop systems. For larger capacity operations, open systems will be preferred. Furthermore, the exterior of such closed-loop systems may become heavily fouled, necessitating periodic removal for cleaning. 

Unlike cold-cleaners, vapor degreasers lose relatively small amounts of solvent as solid waste or liquid drag-out. Most emissions are due to vapor loss and the loss level is highly dependent on operator and operating conditions. Solvent losses for a poorly operated open-top vapor degreaser may be eight or more times greater than for a well-operated unit (Branson Ultrasonics Corporation, 1988). 

To avoid pump cavitation on start-up, the experienced operator opens the pump discharge valve slowly. Slowly opening the discharge valve results in reduced acceleration of the liquid in the suction line and a slower rate of the conversion of suction pressure to velocity. 

This results in a temporary loss of pressure at the suction of the pump. This temporary loss of pressure is called the starting NPSH requirement. The more quickly the operator opens the discharge valve of a pump, the more rapidly the liquid accelerates in the suction line. This increases the starting NPSH required. 

Existing operational open systems often contain biomass and air-blown foulants. Both open and closed-loop systems may contain process contaminants, corrosion products, and various types of deposits. The deposits typically consist of mineral scales and other materials resulting from inadequate water treatment practices. 

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