Standby plant

Where the switching of plant is purely manual, the plant instructions should specify the limits of control, and not leave these to the shift operator, who may not be sufficiently skilled to take the correct decisions. Standby plant is often fitted, and it is part of the operation discipline to change over machines to ensure that they get even wear and keep all sets in running order. All operation staff should be aware of the method of bringing standby plant into use in an emergency. Where refrigerant valves need to be opened or... 

Standby plant needs to he run frequently, hoth to ensure that it is in working order, and also to keep items such as shaft seals oiled and run-in, and thus gas-tight. The location and function of any changeover valves which must he operated in conjunction with standby plant should be clearly marked. 

Once the first sulfur plant has been required, a second standby plant is usually required to provide absolute capability for handling all sulfur-containing streams in the event of the first plant shutdown. If sulfur oxide emissions are limited by law, then the refiner is faced with shutting down the refinery if the first sulfur plant is down and a second plant is not available. Hydrogen sulfide can no longer be disposed of by burning where the sulfur oxides are discharged to the atmosphere. 

The literature ([5-27], [5-28], [5-29]) provides failure rates for diesel standby plants which differ by several magnitudes. However, since the question posed can only be answered with the help of quantitative analysis, a statistical analysis of the operational behavior of diesel plants is indispensable for the determination of reliable failure rates. Figure 5.26 shows how many influence factors may lead to the failure of a diesel plant. This, in turn, requires that the failure rates for standby diesel power plants be determined as to type and mode of application. For this purpose, voluminous data on the operational behavior of standby diesel plants is required. This data can never be collected from the behavior of standby diesel plants under blackout conditions alone, since these blackouts, as mentioned above, are very rare. However, there is another avenue which leads to the acquisition of failure data, namely via monthly trial runs while the public power supply is in full and normal operation. 

The Ube plant consists of four complete trains of Texaco quench-type gasifiers. During normal operation, three gasifiers are on line and one is on standby. Each gasifier consumes 500 t/day of coal to generate syngas for 350 t/day of ammonia. Up to the middle of 1990 the Ube plant gasified 2.2 million t of coal and petroleum coke. 

Most sulfonation plants monitor and control operations by computer. Sulfur-buming catalytic SO -generating equipment may require a 1—2 h stabilization period on startup. The unit can be kept in a standby position by maintaining heat to the unit when it is off-line. Liquid SO -based sulfonation plants do not require such a stabilization period and hence are more flexible to operate than sulfur-buming sulfonation plants. 

Includes capacity at operating plants as well as plants on standby basis. ""Ref. 21. 

Brazil has two small producers of chlorobenzenes. One producer has a capacity of 4.8 thousand metric tons. The other producer s faciUty has a rated capacity of 28 thousand metric tons, which produces mono and ortho for local consumption, and the para may be used in Brazil and possibly exported. A third plant with a 400 metric ton capacity is beheved to be on standby. 

Pipe-hne and marine installations are frequently arranged so that the engine drives all its auxiharies from the crankshaft by means of chains and V belts. But process-plant practice is to have all the auxiliaries independently driven, using standby pumps to minimize engine downtime. 

Power plants in both peaking and standby modes aehieved 30,000 hours between major overhauls. It was during these operations that the deposit problem on the turbine nozzles beeame apparent. Also, deposits developed on the fuel nozzles, a situation that eould eause deviation in the fuel spray angle and related eombustion problems. Therefore, both turbine and fuel nozzles needed frequent eleaning. 

Driver. If steam is available, a common choice is a steam turbine driver for the main pump and an electric motor for standby. Some plants prefer two electric motor-driven pumps. Give the minimum steam condition. Give the expected voltage drop on the electric system if more than 10% is expected, especially on large systems. 

Can start-up and shutdown of plant, or placing of plant on hot standby, be expedited easily and safely ... 

Backup systems which depend upon the action of automatic cut-in devices (e.g., a turbine-driven standby spare for a motor-driven cooling water pump, with PLCI control) would not be considered an acceptable means of preventing a utility failure for normal pressure relief design purposes, even though their installation is fully justified by improved continuity and reliability of plant operations. 

Hoechst Celanese officials said it was too early to decide whether to rebuild the butane reactor, install a newer methanol-to-acetic acid process, or start up a standby acetic acid facility at Hay City, TX, to replace the idled 350-million-lb per year acetic acid plant. 

The separation plant had been running smoothly for several weeks and the planned shutdown was some time away. On the day of the incident a number of unusual events occurred which contributed to its development. Shortly after the start of his day shift, the control room operator received a high vibration alarm from booster pump A in the crude fluid separation building. Following normal procedure, he switched over to the standby pump (pump B), switched off pump A, and told his supervisor of the alarm. The supervisor subsequently organized a work permit for work to be carried out on pump A by the day shift maintenance team. The permit was issued and repair work... 

At shift handover at 18 00, the incoming operations supervisor was briefed by the day supervisor. The conversation centered on the vibration fault and subsequent repair work carried out. However, no mention was made of the work on the PRV, so consequently none of the incoming shift were aware of it. The night shift supervisor, wanting to return pump A to standby as soon as possible, asked the plant operator to check the status of the pump, and together with the shift electrician, to reset it and put it back on stand-by. The operator, unaware of the work being done on the PRV, did not check this part of the system and, following inspection of the pump, returned it to stand-by. 

Supervisor had requested pump A to be prepared for standby. Did this by asking plant operator to prepare pump and electrician to reset pump. This request was made at about 19 00. 

All process plants require both steam and electric power in their operations. Power is cither purchased from local utility companies or generated at the plant site. Even if power is generated by the process plant, arrangements for standby power from the local utility must be made for emergency purposes. Steam is rarely purchased but is generated at the plant for use in the process and as a driving medium for pumps and compressors. 

Diesels are used in many industrial applications (for example, for base-load generation in mines, cement plants and in remote regions of the world). In addition, they are often utilized to provide standby power for hospitals, telecommunications, banks, computer centers and office complexes that must have full independent power capability. The diesel can be started rapidly, making it ideal for peak lopping duties to meet maximum load demands, or for emergency use in cases of power supply interruptions. 

The supply system for the power plant auxiliaries, including the provision of supplies to any important drives and the provision of standby supply systems. The protection and synchronizing schemes applicable to the generator circuit. 

This chapter introduces the basic items of design and specification for the principal systems and components of an electrical industrial installation. Electrical supply systems are discussed with regard to interface with the supply authorities and the characteristics. Salient features of switchgear, transformers, protection systems, power factor correction, motor control equipment and standby supplies are identified and discussed together with reference to the relevant codes of practice and standards. The equipment and systems described are appropriate to industrial plant installations operating at typically 11 kV with supply capacities of around 20MVA. 

Energy can be conserved by operation of plant in such a way as to minimize part loading. Various practices can be adopted that can be described as good housekeeping . In addition to maintenance, this will include such factors as the avoidance of plant operating in the standby mode for long periods, operation at correct temperature, ensuring doors are closed where applicable, etc. 

On medium-sized boiler plant where gas is to be the main fuel, it may have oil as a secondary standby fuel. In this case, the chimney height must be based on the grade of fuel oil capable of being burned. 

The second area will be feedwater pumps. It is normal to have a duplicate standby feedwater pump. Sometimes this may be two for each boiler or one duplicate pump to serve any selected boiler. These will usually require manual changeover in the even of failure of the duty pump. It is practical to automate this changeover by using pressure sensors and motorized valves. The same can apply to oil-circulating pumps, gas boosters, water-treatment plant and any other valves and motors. It is possible to do most things, but in the end there is the cost to be considered. An... 

The function of these is to prevent the room becoming cold and humid in the event of the main plant being off for any reason other than power failure. For a small input they can protect the conditioned space to a large degree and greatly reduce reconditioning time upon restoration of the main plant. They would require a comparatively small input from a standby generator. 

Plant and equipment that provides a service or is required to operate for 24 hours a day, 7 days a week presents a different proposition to the maintenance programming requirements. For example, a heating pump with a standby, which is required for a heating installation in an office with a set number of working hours from Monday to Friday. Alternative methods of maintenance programming may require the planner to allow for total replacement on plant failure or have available replacement units, so that when an item of plant or equipment fails, it is removed and a replacement installed. 

The ideal method would be that all plant or equipment units have a duplicate or redundant standby that on failure would automatically be brought into service. This is satisfactory when considering small, less expensive units, which are installed to ensure that the services they are providing are not disrupted (this could also include auxiliary items on major plant and equipment). However, due to the capital costs of the major unit itself, it would be... 

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