Spare Capacity Available

If the demand for capacity exceeds the spare capacity available, actual available capacity is to be distributed according to a formula determined by the operator.20 However, the owners enjoy certain preferential rights when capacity is scarce. An owner has relative priority for its needs up to twice its equity interest in the network.21... 

Tray spacing. For the bottom section, 24 in is appropriate (1). For the top section, there may be some spare capacity available, so that a smaller tray spacing (18 in) is preferred. Assume... 

Spare capacity available in the installed equipments (which are fixed on position) for taking up outside jobs,... 

The terms able to promise or available to promise (ATP) indicate whether a given customer, product, volume, date, or time request can be met for a potential order. ATP requests might be filled from inventory, unallocated planned production, or spare capacity (assuming additional production). When the production scheduler is content with the current plan, made up of firm orders and forecast orders, the forecast orders are removed but the planned production is left intact. This produces inventory profiles in the model that represent ATP from inventory and from unallocated planned production (Baker, 1993 Smith, 1998). 

It follows from section 61 of the PR that the owner of the upstream network shall make spare capacity (...) in the primary market available to the operator, who shall make it available collectively and that agreements are are to be entered into with the operator on behalf of the owner . 

System performance requirements (e.g., timing, memory storage, availability, and spare capacity)... 

The production of triple superpho.sphate with a P2O5-content greater than 40% and biologically more available phosphorus reached a peak in 1984 and has declined 30% since then. The worldwide capacity for triple superphosphate is considerably underutilized. Part of the spare capacity can be utilized for the manufacture of ammonium phosphate. The world production by region in 1990 is given in Table 2.5-5. 

Consideration must be given to the thermal state of the feed this state should either be kept constant or be adjusted in the manner anticipated under low-rate operation conditions. Often, spare capacity is available in a preheater or a precooler when the column operates at low rates, and this can be utilized. 

Subject to availability of an external recycle stream, as well as spare capacity in the column section below the side draw, configuration 19.6c can also be used. However, this scheme is energy-wasteful and will usually accomplish little more than the IVC. 

Moulded case circuit breakers are also available for incoming and busbar section purposes, with ratings up to 6000 A and service voltages between 220 V and 660 V. (At 415 V a 4000 A circuit breaker would satisfy the duty of a 2500 kVA feeder transformer with about 15% spare capacity.) These are also available as 4-pole units. Circuit breakers having ratings of 800 A and above are often provided with several adjustments that widely modify the shape of the complete protection curve, as described in Chapter 12. This enables the curve to coordinate with almost any other protective device or equipment that is immediately upstream or downstream of the circuit breaker. Some circuit breakers with the higher rated currents are also provided with integral earth fault protection facilities. 

These items are required regularly, and some of the existing machineries/reactors can be used to produce them since spare capacity is available in-house. 

Example. The salt equivalent to 800 tpd NaOH is 1,169 tpd. To calculate the need for raw salt, we allow 0.37% for impurities, 4.5% for water, and 1% for in-process loss. This gives us 1,241 tpd. We must also allow for in-process use of NaOH if we are to have 800 tpd available for sale. A 3% allowance raises our salt requirement to 1,280 tpd. We round this up, to allow for extra mechanical downtime and to provide some spare capacity, to 1,500 tpd. 

In view of the attractive features of carbon dioxide, it seems certain that any further hop extraction plants will employ CO2 as have all the recently built plants. Because of the flexibility available in the choice of operating conditions for a supercritical plant and the possibility of using any spare capacity for other purposes such as decaffeination of tea or coffee, it is also probable that any future hop extractors will be basically supercritical, but capable of operating under liquid or near-liquid conditions. 

When installing new facilities in an existing refinery, determine whether or not there is any excess capacity in the existing utility systems and how much is available for the design in question. Utilize this spare capacity wherever possible. 

The committee reviewed the process control systems at the TOCDF and ANCDF in detail to assess their capability and capacity to handle current and forecast workloads. In addition, maintenance procedures, spares supportability, reliability, and availability were evaluated. The control systems at these sites are typical of those at the other two incineration sites. 

In de Smidt-Destombes et al. (2004) the tradeoff between repair capacity and spare part inventory control is investigated for a single k out of N system under condition based maintenance i.e. when the number of defect components exceeds some previously defined limit, maintenance is initiated. They propose exact and approximate methods to analyze the system availability. Continuing along these lines, de Smidt-Destombes et al. (2007) considerM identical k out of N systems under block replacement. For each system all defect components are replaced every fixed time interval. Two methods are proposed to analyze the system availability as a function of the number of spare parts stocked and the block replacement interval. The main difference between these studies and our contribution is that in our contribution we focus on applying a cost structure, while their focus is on estimating up-time. Furthermore, we consider multiple different systems, while de Smidt-Destombes et al. (2004, 2007) focus on either just one system, or on multiple identical systems. Finally, in our model maintenance is immediately initiated when equipment fails. 

Markov processes have been widely used to analyse and assess the performances (reliability, availability, maintainability, production capacity, etc. ..) of many complex dynamical systems with inter-component and functional dependencies (cold spare, shared load, shared resources,...). This section e q)lores the development of the differential importance measure in the context of Markov models at steady state. 

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