Batteries limitations

The battery limit is a geographic boundary which deflnes the manufacturing area of the process. This includes process equipment and buildings or structures to house it but excludes boilerhouse facilities, pollution control, site infrastructure, etc. 

The battery limits investment may be estimated by applying installation factors to the cost of individual items of equipment ... 

In addition to battery limits investment, off-site investment is required. This includes all structures, equipment, and services that do not enter directly into the chemical process. Within this broad category there are two major classifications, namely, utilities and service facilities. 

Batteries, storage Battery chargers Battery grids Battery limit Battery oxide Battery packs Battery plates... 

Insect toxins Inside battery limit m situ Diagnostics... 

Fig. 1. Snamprogretti thermal stripping urea process. BL = battery limits.

Eor this example the cost of the battery limits plant is about four times the purchase cost of the equipment. This number is about two for module I-type plants designed and iastalled by the fine chemicals company itself, and about six for expanded module IV-type plants designed and built by contractors. 

Multielevation piperacks are usually needed to handle all the required services for piping, electrical, utilities, and instmmentation. The two-level rack is one of the most common but three-level ones are also used. The utility lines are usually mn in the upper level and the process lines in the lower levels. The larger-diameter lines are located to the outside of the rack to be closest to the column supports. Access platforms are required at the battery limit to provide operators access to the block valves and blinds. If long mns of hot pipe are required, a portion of the pipe rack needs to be dedicated to an expansion loop. A horizontal space in the piperack is provided for a set of lines to be flat-turned into a set of expansion loops with the large pipes located on the outside. AH of the pipe turns are in the same horizontal plane, which is an exception to normal piping practice. A flat turn takes up and blocks space for other pipes. Flat turns are generally only made from the outside of the rack to minimize this blockage. 

Fig. 14. Outside battery limit (OSBL) equipment spacing. Minimum spacing for off-site equipment is in meters. Classifications of tankage are Class 1 high ha2ard, flash point below 38°C Class 2 low ha2ard, flash point above 38°C. NFPA = National Fine Protection Association. Safety standards are calculated...

The fixed capital estimate depends on the definition of the plant. A grass-roots plant is a complete faciUty at a new location, including all utihties, services, storage faciUties, land, and improvements. If a process plant is located at an existing processing complex, it can usually share some of these auxihary faciUties. A battery-limits plant is defined as the process faciUty itself, so that the auxiUaries, off-site, and land-related items are excluded from the fixed capital estimation. However, a battery-limits plant maybe assigned allocated capital charges for the share of common utihty and service faciUties used by the plant. 

At processing complexes, central utiUties and other faciUties are shared by several battery-limits process plants. The capital cost of a central utiUty is sometimes charged to the capital cost of each battery-limits plant as an allocated capital cost based on the unit capital cost of the utiUty faciUty and the units of capacity of the utiUty required by the plant. In this case, the use charge per unit consumed only covers operating expenses. The alternative is to recover utihty capital costs, as well as operating expense, in the unit usage charge. 

The Viola method is a typical predesign approach based on the number N of principal processing blocks, the production rate P in tons per year, and a complexity factor K The 1981 battery-limits cost C in dollars can be correlated to K and P ... 

As an example, the battery-limits capital cost can be estimated for the production of 10,000 t/yr of ethylene (qv) from ethanol (11). Seven processing blocks, ie, vaporizer, reactor, water quench, compressor, dryer, distillation, and energy recovery, can be identified. The highest temperature is 350°C (reactor), and the highest pressure is about 1.7 MPa (17 atm) (compressor, two towers). If a materials-pressure factor, + of 1.03 is assumed, then for N = 7 0 = 0.87 1/0 = 1 64 and f =0 K = 6.3. This gives the 1981 cost as 4.4 X 10 . The 1991 battery-Hmits investment can be obtained, by updating with the CE Plant Cost Index, as 5.3 x 10 . ... 

An overall Lange factor, E- j can be used to relate the battery-limits fixed capital investment Jg to the deHvered equipment cost Eg, so that... 

For the same production capacity, the oxygen-based process requires fewer reactors, all of which operate in parallel and are exposed to reaction gas of the same composition. However, the use of purge reactors in series for an air-based process in conjunction with the associated energy recovery system increases the overall complexity of the unit. Given the same degree of automation, the operation of an oxygen-based unit is simpler and easier if the air-separation plant is outside the battery limits of the ethylene oxide process (97). 

Total Capital Cost The installed cost of the fixed-capital investment Cpc is obviously an essential item which must be forecast before an investment decision can be made. It forms pai4 of the total capital investment Cfc, defined by Eq. (9-14). The fixed-capital investment is usually regarded as the capital needed to provide all the depreciable facihties. It is sometimes divided into two classes by defining battery limits and auxiliaiy facilities for the project. The boundary for batteiy limits includes all manufacturing equipment but excludes administrative offices, storage areas, utihties, and other essential and nonessential auxihaiy facilities. 

Base equipment includes all equipment within the battery limits whose cost is as significant as the cost of a pump. For example, storage tanks, knockout drums, accumulators, heat exchangers, and pumps are classed as main-plant items (MPl). Early in the development of the process-flow diagram, it is advisable to increase the estimated (MPl) cost by 10 to 20 percent to allow for later additions. When the scope of the process has been well defined, (MPl) costs should be increased by 1 to 10 percent. 

Single-factor methods collect the various items of expenditure into one factor, which is usually used to multiply the total cost of delivered equipment X (Ce( )del lo give the fixed-capital cost for plant within the battery limits ... 

Eng., 72,226-236 (Sept. 13. 1965)] expresses auxiliary costs as factors of the battery-limit (BL) cost. Table 9-52 gives the factors from the breakdown of Miller, which is more detailed than that of Woods. 

Details Grass-roots plants Battery-limit installations ... 

Battery-limit costs (range of factors iu percent of basic equipment) average unit cost of main-plant item (MPI)... 

The above factors apply to those items normally classified as building services. They do not include (1) services located outside the building such as substations, outside sewers, and outside water lines, all of which are considered to be outside the battery limit as well as outside the building and (2) process services. 

Inside boundary bmits field costs 2192 2024 Inside battery limits field cost 2829 2416 2390... 

Total field cost 3170 2992 Outside battery limits field cost 488 481 452... 

This discussion of offsites is subdivided into Utilities and Other Offsites. The utility portion interacts with the process area, while the other offsites have minor interaction w ith the process area, if any. In addition, the process area may have utility generation, such as waste heat boilers. It is convenient to discuss all utility generation as one package pointing out special considerations for the process area units along the way. The goal for this study phase is the same as for battery limits specification complete major material list and process specification sheets. 

Wastewater Treating. Earlier we discussed the importance of bringing environmental experts into the project early. Wastew ater treating can be part of the battery limits process area in the case of phenol extraction from coal gasification gas liquor, but this is an e.xception. 

Early in the life of a project, information has not been developed to allow definitive cost estimates based on material takeoff and vendor quotes for equipment. Therefore, it is necessary to estimate the cost of a facility using shortcut methods. The first step is to develop or check flow-sheets, major equipment sizes, and specification sheets as described in earlier chapters. From the equipment specification sheets, the cost of each piece of equipment is estimated, using techniques discussed later. Once the major equipment cost has been estimated, the total battery limit plant cost can he quickly estimated using factors developed on a similar project. 

Typical Factors as % of Total Cost of Battery Limits... 

Once the battery limits have been summed, the offsite (the difficult part) must be estimated. Since there is so much variation from site to site, and between grassroots plants and construction at existing sites, the use of factors is not recommended. 

Total Offsite Costs. The offsite costs can range from 20% to 50% of the total cost of the project. If a preliminary built-up estimate of the offsites is less than 30% of the total costs, it should be suspect. Unless the offsites are very well defined, it would be better to use a factor of 50% to 75% of battery limits estimate as the offsite figure. 

An alternative to a factored estimate, in some cases, can be a scaled estimate if the battery limits cost of a similar plant is known, but the size is different. The cost of the new plant, C , is equal to the known plant cost, C, times the ratio of the two plants capacity raised to a fractional power. That is ... 

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