Capital cost compressors

In the case of a liquid recycle, the cost of this pressure increase is usually small. Pumps usually have low capital and operating costs relative to other plant items. On the other hand, to increase the pressure of material in the vapor phase for recycle requires a compressor. Compressors tend to have a high capital cost and large power requirements giving higher operating costs. 

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 . ... 

Smaller size and lower capital cost than same capacity range of reciprocating compressors. 

The objective function is comprised of the sum of the annual operating and maintenance costs of the compressors and the sum of the discounted capital costs of the pipeline segments and compressors. The annualized capital cost for each pipe section is assumed to be proportional to its length and its diameter. Similarly the annual operation and maintenance charges of a compressor is assumed to be proportional to the horsepower which is given by... 

Figure El 3.4b shows two different forms for the annualized capital cost of the compressors. Line A indicates the cost is a linear function of horsepower [ 70.00/(hp)(year)] with the line passing through the origin, whereas line B assumes a linear function of horsepower with a fixed initial capital outlay [ 70.00/(hp)(year) + 10,000] to take into account installation costs, foundation, and so on. For fine A, the objective function in dollars per year for the example problem is...

Compressor station Compression ratio Capital cost ( /year)... 

For large quantities of hydrogen, pipeline delivery is cheaper than any other option. Pipelines are characterised by very low operating costs, mainly for compressor power, but high capital costs. The investment for pipelines is in proportion to the delivery distance, while the influence of capacity is lower. 

Fuel cell pressurization is typical of many optimization issues, in that there are many interrelated factors that can complicate the question of whether to pressurize the fuel cell. Pressurization improves process performance at the cost of providing the pressurization. Fundamentally, the question of pressurization is a trade-off between the improved performance (and/or reduced cell area) and the reduced piping volume, insulation, and heat loss compared to the increased parasitic load and capital cost of the compressor and pressure-rated equipment. However, other factors can further complicate the issue. To address this issue in more detail, pressurization for an MCFC system will be examined. 

Oxidant Utilization In addition to the obvious trade-ofFbetween cell performance and compressor or blower auxiliary power, oxidant flow and utilization in the cell often are determined by other design objectives. For example, in the MCFC and SOFC cells, the oxidant flow is determined by the required cooling. This tends to yield oxidant utilizations that are fairly low (-25%). In a water-cooled PAFC, the oxidant utilization based on cell performance and a minimized auxiliary load and capital cost is in the range of 50 to 70%. 

Compressor Intercooling Whether a compressor should be intercooled or not depends on the trade-off between the increased efficiency of the intercooled compressor and its increased capital cost. In general, intercooling is required for large compressors with pressure ratios that exceed approximately 5 1 (44). The designer also should consider whether the heat is advantageous to the process. For example, when near the 5 1 pressure ratio, it may not be appropriate to intercool if the compressed stream will subsequently require preheating as it would with the process air stream of an MCFC or SOFC system. 

The capital cost of air separation machinery is linked to both the size of the beds (which dictates the cost of piping valves), of course to molecular sieve inventory and to the size of the compressor required to run the process. A low product recovery may have little impact on the bed size factor but it has an enormous effect on the amount of gas required and on the cost of compressing that gas. Thus the recovery and bed size factors have direct links to the cost of capital and operations of air separation machines. 

The major costs involved in a home refrigerator are the capital costs of buying the compressor, the heating and cooling coils, the circulation pipes, and the expansion valves, as well as the yearly operating cost of electricity and maintenance. 

Initial capital costs for the Alpheus Model 250 and support equipment used during this experiment are as follows Alpheus Model 250, 107,000 compressor, 81,000 CO2 storage tank, 46,000 air dryer, 21,000. Total capital costs were listed at 255,000 (D15087I, p. 10). 

The capital costs for an ES-300H unit tested by the U.S. Navy at Naval Air Station North Island were estimated to be 50,000. For the test, electric power costs were calculated to be 6.78 per day, which would equal 2475 per year. This estimate includes the cost of operating the unit as well as the cost of running an air compressor required for treatment. Based on demonstration results, monitoring costs for the unit would add an additional 6300 per year (180 worker-hours per year at 35 per worker-hour) (D21558H, pp. 4-1, 4.2). 

We start by studying the steady-state design and economics of a process with a single adiabatic reactor. The design considers the entire plantwide process reactor, heat exchangers, gas recycle compressor, preheat furnace, condenser, and separator. The economic objective function is total annual cost, which includes annual capital cost (reactor, catalyst, compressor, and heat exchangers) and energy cost (compressor work and furnace fuel). 

Capital cost = reactor + catalyst + furnace + heat exchangers + compressor Operating cost = furnace energy cost + compressor work — steam credit... 

The upper curves add the investment for onsite power generation to that for compressor and heat exchanger to show energy supply effects. For any exchanger AT there is a minimum investment. This point is between 1.8 and 2.3 times the / s of the idealized process. There is an optimum At (4°F) for which both investment and energy efficiency are better than for the other two cases. Note that a plant can be designed to operate with a 3°F At and use about 75% of the power required for a 5°fAt at the same capital cost. 

---