Production Of Compressed Air Research Articles

Railway Rolling Stock Compressors Capacity and Main Reservoirs Volume Calculation Methods

Existing railway rolling stock compressors capacity and main reservoirs volume calculations methods were created in 1960−1970 and do not take into account the achievements of modern railway pneumatic technologies and the results of calculations of compressor capacity and main reservoir volume is inaccurate. The new calculation technology begins from total compressed air consumption for braking processes, air leaks and auxiliary needs definition. Knowing all compressed air consumption possibilities, compressor capacity is calculated. Then it is possible to calculate compressed air production system main reservoirs volume. Calculated compressor capacity and main reservoirs volume should be equal to air consumption for train brakes release and charge after service or emergency braking, for this purpose balance equation between produced and charged air is used. If railway rolling stock is operated in high humidity conditions without composed air dehumidification system main reservoirs useful volume decreasing. For that specific climate conditions compressor capacity should be corrected.

Дослідження шляхів підвищення енергетичної ефективності виробництва стисненого повітря в шахтних компресорних установках

Дослідження шляхів підвищення енергетичної ефективності виробництва стисненого повітря в шахтних компресорних установках

A cost-effective compressed air generation for manufacturing using modified microturbines

Compressed air is an irreplaceable energy source for some manufacturing processes, and is also common in applications even when there are alternatives. As a result, compressed air is a key utility in manufacturing industry, but unfortunately the cost of compressed air production is one of the most expensive processes in a manufacturing facility. In order to reduce the compressed air generation cost an unconventional way using a microturbine configuration is proposed. The concept is based on an extraction of a certain amount of compressed air from/after the compressor with the residual air flowing to the turbine to produce sufficient back power to drive the compressor. A thermodynamic and life cycle analysis are presented for several system variations, including a simple cycle without a recuperator and a complex configuration with an intercooler, recuperator and reheating. The study is based on the typical requirements (i.e. quantity, pressure) for a small to medium sized industrial compressed air system. The analysis is focused on the North American market due to the low price of natural gas. The lowest life cycle cost alternative is represented by a microturbine concept with a recuperator, air extraction after partial compression, intercooler and aftercooler. A comparison of an electric motor and conventional microturbine prime movers demonstrates the economic benefit of the proposed compressed air generation method, for the design parameters and utility prices considered.

ANALYSIS AND OPTIMIZATION OF MECHANICAL UTILITY SYSTEM

The present paperhas discussed the analyzing and optimizing methodology of mechanical utility systems.A study was carried out at Melog Speciality ChemicalsLtd with the aim of optimising the company’s utility system efficiency. Energy conservation is a worldwide, concern and an important consideration for any industry. In a chemical plant, amajor portion of the supplied energy is consumed in the production of compressed air. This compressed air is used for various applications. Hence in order to increase the efficiency of the plant the input energy supplied has to be decreased by making use of the most effective methods of compression which indirectly results in asaving of power.The paper revolves around the main objective of reducing the compression cost of air. This aim has been theoretically achieved by replacing the existing reciprocating compressor with a screw compressor. Cost saving due to the use of screw compressor is achieved because it requires low motor power to operate as compared to its reciprocating counterpart. Also, thereciprocating compressor needs frequent maintenance of various components like v- belt, piston rings, piston, etc. whereas screw compressor does not require frequent maintenance which decreases the compression system’s maintenance downtime. As there is no intercooler required in screw compressor the need to pump the cooling water at an intermediate stage of compression is eliminated, which is otherwise necessary for optimum operation reciprocating compressor.

Assessment of a Diagnostic Procedure for the Monitoring and Control of Industrial Processes

The definition of “energy efficiency” entails programming, planning and implementation of operational tools and strategies leading to the reduction of energy demand for the same offered services. Among the typical industrial energy uses, the production of compressed air represents certainly an important segment of potential saving. The present work studies the monitoring of the compressed air used for blow moulding of a packaging solution company. The study addresses the monitoring of compressed air line in term of operational and energy variables. The available measured data are used to evaluate the energy performance evolution during a year time. The work tackles the problem with two different approaches based on univariate and multivariate methods. The first method aims at finding a key performance index and a new univariate control chart related to energy/operational parameters to better monitor the performance of the compressed air plant. Besides, the multivariate analysis of the production process is applied in order to analyse the energy efficiency by also considering the multiple variables influencing the whole process itself. Final purposes are identify a new methodology for the production process analysis and evaluate flaws and strengths of these models.

Model based design of an intercooled dual stage sliding vane rotary compressor system

Energy saving is currently one of the most important driving factors for innovation all over the world. With reference to global electricity consumptions, electrical energy for compressed air production accounts for 4-5%. Among the rotary compressor technologies, Sliding Vane Rotary Compressors (SVRC) are characterized by noteworthy specific energy consumptions and demonstrated an unforeseen energy saving potential thanks to some intrinsic features specifically related to this kind of machines. The paper presents a further reduction strategy to lower energy consumptions in compressed air systems using SVRCs that relies on the combination of the recent use of a pressure swirled oil injection technology and a dual stage intercooling. The synergy between technologies already mature approaches to the lowest energy consumption and candidates SVRCs as superior machines in the energy context. The saving potential compared to the technology at the state of the art was evaluated thanks to a comprehensive mathematical modeling of the two compressor sections and the intercooling heat exchanger and fan. Results showed a reduction of the electrical power required to drive the compressor system up to 9.5%. The overall approach represents a model-based design for a new machine which is under development.

Optimization of a network of compressors in parallel: Operational and maintenance planning – The air separation plant case

A general mathematical framework for the optimization of compressors operations in air separation plants that considers operating constraints for compressors, several types of maintenance policies and managerial aspects is presented. The proposed approach can be used in a rolling horizon scheme. The operating status, the power consumption, the startup and the shutdown costs for compressors, the compressor-to-header assignments as well as the outlet mass flow rates for compressed air and distillation products are optimized under full demand satisfaction. The power consumption in the compressors is expressed by regression functions that have been derived using technical and historical data. Several case studies of an industrial air separation plant are solved. The results demonstrate that the simultaneous optimization of maintenance and operational tasks of the compressors favor the generation of better solutions in terms of total costs.

Theoretical modeling and experimental investigations for the improvement of the mechanical efficiency in sliding vane rotary compressors

Positive displacement compressors lead the market of compressed air production for industrial applications. Among them, sliding vane rotary compressors represent an energetically virtuous alternative to the current compression technologies. In the present work, the effects of compressor design parameters were investigated through a comprehensive approach that aimed at addressing more efficient machines to promote sliding vane compressors as the key enabling technology in compressed air systems. A comprehensive mathematical model was developed to study the main phenomena occurring in this kind of compressors. The model provides the cell volume evolution over a whole rotation during which filling, compression and discharge processes occur. The first and latter phases are described by the quasi-propagatory approach that represents the inertial, capacitive and resistive features of one-dimensional unsteady flows. The dynamics of the compressor blades led to four different arrangements inside the rotor slots while an analysis of the hydrodynamic lubrication established between blade tip and stator wall focused on the oil film thickness evolution to prevent dry contacts. An extensive experimental campaign on a mid-size industrial compressor allowed the model validation at different outlet pressure levels and revolution speeds using a direct measurement of mechanical power and the reconstruction of the indicator diagram from piezoelectric pressure transducers. The friction coefficient at the contact points between blades with stator and rotor was estimated in 0.065 and further improvements of the mechanical efficiency were eventually addressed considering the roles of compressor aspect ratio, revolution speed, and blade tilt. The first two theoretical optimizations might lead to an increase of the compressor efficiency of 2 and 9 percentage points respectively. On the other hand, acting on the blade tilt would not produce relevant improvements.

Simulation and Performance Comparison of a Real-Time Controller for a Fixed-Speed Multipressure Compressor

This paper introduces a new configuration in the compressed air production, which aims for a more efficient energy layout and innovative air network control and feeding. The target is achieved by applying a real-time earliest-deadline-first (EDF) scheduling technique to the management of the air production and delivery, seen as an energy service. The control action in a closed loop is applied to the activation/deactivation of valves, delivering air to networks operating at different pressure levels. The new configuration deals with a single compressor, which has a fixed speed and is electrically driven, and a centralized type of production, which is an alternative and is more efficient to a decentralized one. A set of suitably controlled valves intercepts air at the desired pressure level and feeds the networks while their operation guarantees that each pressure level is kept inside safe ranges. The algorithm integrates with a previous work. Future developments are also anticipated.

Energy audit experiences in foundries

Steel industry presents one of the highest energy demand of all the industrial sector. Foundries have a really relevant role both in economical terms and as regards the energy demand. The cost of energy represents several percentage points of the overall costs of a foundry. The electricity demand is very high, particularly for the induction melting furnaces. A large amount of thermal energy is obtained both from natural gas combustion and from the coal needed for the process of formation of cast iron in cupolas. Moreover, the plant services must be considered: one very energy consumer is compressed air production. Every factory is different from another so that the proposal of actions of energy savings or thermal recovers requires a detailed study of each plant considering the lay out and analysing the single processes with related energy needs and thermal levels. The co-operation of the University of Padua with the Centro Produttività Veneto allowed to plan a series of energy audits in some foundries located in Vicenza province. The experiences of the first facilities surveys and audits recommendations demonstrated both potential advantage of energy savings and the related difficulties, often due to the high investment costs. Anyhow the joint work of auditing between the university experts and the foundry technicians produced a better awareness on the critical points of the plant and a higher rationality level in the evaluation of investments for the renewable of the machinery. Here, the method of performing the energy audits is described together with the very first results in terms of proposals for energy savings evaluated technically and economically.

Sliding vane rotary compressor technology and energy saving

Energy saving, CO2 reduction, and energy generation from renewable sources represent the three cornerstones of the energetic and environmental commitments of all the countries in the world. These three elements may give a quantitative contribution to the sustainability in an industrial environment. Among them, the most important one, that represents a driver in many sectors, is the limitation of the CO2 concentration in the atmosphere: most recent data (2013) from National Oceanic and Atmospheric Administration – Earth System Research Laboratory (NOAA-ERSL) set at 395.55 parts per million (ppm) the CO2 in the atmosphere and the continuous increasing trend will quickly allow to reach the 450 ppm level which is considered as a safeguard limit to avoid irreversible environmental and socioeconomics problems. Looking at the energy consumption side, energy saving is a key factor. Compressed air production does not escape this requirement and, for the compressor manufacturing industry, this can represent an opportunity with great potential benefits. Compressed air is produced by electrical energy and the consumption accounts as much as 10% of industrial consumption of electricity. A lower estimate places at 6% this share but an additional 12% is estimated to be associated with the commercial and residential markets (portable tools, air pumps, pneumatic heating, ventilation, air conditioning, etc.). Hence, the overall compressor needs are estimated equal to 20% of the industrial electricity needs. Considering that industrial consumption of electricity represents a given share of the overall electrical energy consumption (it depends on the geographical context, social development, industrial level, etc.), with good approximation, compressed air can be associated to the overall electricity consumption and to primary energy consumption too. So, it can be compared with the other energy alternatives when the data are reliable and referred to real situations, actions to promote energy efficiency in compressed air systems can be identified with their real importance and compared with all the other measures. From many independent studies the most important energy saving measures are associated to the: (1) reduction of leakages on the distribution lines, (2) a more appropriate compressed air system design, (3) use of adjustable speed drives, (4) waste heat recovery. All these aspects, in a 10-year period of operation, weigh 70–75% of the overall compressed air costs. Therefore, the compressor technology is a key factor to reduce energy consumption including in it load control, variable speed operation, compressor sizing, etc. A great potential saving is associated to leaks, friction pipes, etc. but these actions are downstream of the compressed air production. After having discussed some issues concerning the future overall energy consumption and CO2 emissions, considering the development of the electricity market in the world in the near future, and overall energy characteristics of existing machines widely used in the compressed air market, the article goes deep inside a specific compressor technology which is represented by the sliding vanes rotary type. Principal processes inside these machines are discussed in the light of the recent scientific literature advancement of a theoretical and experimental nature. The general idea was that these machines are not so well known and their use is not so widespread: thanks to a deeper scientific interest over the past few years, these compressors had a notable performance improvement, thus a greater potential in industrial applications. Thanks to some intrinsic aspects, some energy issues are presented and related to specific processes inside the machine and compared with other compressors. The potential further improvements in terms of specific energy are discussed and addressed in main future research directions.

Dynamic modeling of compressors illustrated by an oil-flooded twin helical screw compressor

Compressed air is a basic energy source in several industrial areas. The energy of pressurized air is used during manufacturing processes, commonly as driving force for actuating pneumatic cylinders and in power tools such as pneumatic screwdrivers. The widespread use of this energy source justifies efforts to reduce losses within the compressed air infrastructure. One of the main energy consumers in the network is the production of compressed air. Thus, one problem area is generation with compressors of different kinds and sizes. Another problem affects the transmission through piping networks with non-negligible leakage effects adding to energy losses within the pneumatic infrastructure. This paper focuses on the process of compressing air and describes a dynamic simulation model of an oil-flooded screw compressor. A single compressor block, part of an overall compressor station, is split into four subsystems which are presented as mathematical models. Simulation results are compared to physical measurements and studied with respect to energy losses. The presented model is detailed enough to account for dynamic effects in real machines. But it is also abstract enough to be integrated in further simulations with more components. Future work will be done on optimizing compressor station design with respect to the reduction of energy losses.

A New Efficiency Index for Analysing and Minimizing Energy Consumption in Pneumatic Systems

AbstractIn pneumatic systems the consumption of electrical energy depends almost linearly on the production of compressed air. Hence, the operation of the pneumatic line in any application plant has an enormous effect on the overall energy efficiency. In analysis the compressed air system can be divided into three subsystems: production, after treatment (storage and transmission) and consumption. These systems interact with each other and strongly affect overall system energy requirements. Starting from the dynamical models of the subsystems a new generic energy efficiency index (CA-index) is introduced in the paper. It can be used both in one compressor and multi-compressor systems. The fact that the consumption of compressed air may be either pressure dependent or pressure independent is taken into account in the basic equations and in the energy efficiency index. The maximization of the index is carried out by defining and solving a mathematical optimization problem, which then gives the best possible ...

Experiments on Compressed Air Production from Open Channel Flow with Cross-Flow Water Turbine

Experiments on Compressed Air Production from Open Channel Flow with Cross-Flow Water Turbine

Improving Compressed Air System Efficiency—Know What You Really Need

ABSTRACT Compressed air is often the most expensive utility in an industrial facility, and cost-effective efficiency opportunities in both the production and use of compressed air are often ignored by facility operators. Leaks, inappropriate uses of compressed air, poor choice of compressors and ancillary equipment, pressure problems and poor attempts to solve them, and inefficient controls are among the many contributors to compressed air inefficiency in many industrial facilities. Through utility demand-side management (DSM) programs as well as their own efforts, Wisconsin Power and Light customers have been able to improve compressed air system efficiency over the past few years. One customer reduced compressed air operating costs by one third ($17,000/year saved) by reducing air use without reducing production. Another, by monitoring air production and energy requirements of the system, selected a properly sized 75 hp compressor to replace a worn-out 250 hp compressor and paid for the new compressor in less than three years from the energy savings. Many customers reduced air use by replacing open tube blow-offs with air amplification nozzles. Another customer installed a sophisticated multiple compressor control system, saving the cost of the control system in less than four years of reduced energy costs.

Technical Viewpoint: Energy Waste – Industrial Compressed Air Production

Technical Viewpoint: Energy Waste – Industrial Compressed Air Production

Technical viewpoint. Energy waste - industrial compressed air production

Technical viewpoint. Energy waste - industrial compressed air production

The utilization of stand-alone microprocessor units to control energy intensive systems

Most energy intensive process control systems utilize an oversize dedicated computer system. The utilization of stand-alone microprocessor units to control energy intensive systems, reduces costs, facilitates rapid troubleshooting and provides a means to initially inexpensively monitor the operations of these systems to provide control design data. A manufacturing company inquired as to the possibility of reducing their operational costs utilizing computers. This resulted in the design of a multiple, stand-alone and modular Z8 microcomputer configuration to control their steam and compressed air production.

Technical and economic comparison of the alternative systems of pneumatic power supply of mining machines

With the increase in use of compressed air in the industry and the range of working pressures used simultaneously in mining operations expanding, the authors examine six basic configurations of simultaneous air supply to pneumatic drives of mining machines with working pressures of various levels. In these different schemes, the different combinations of compressed air generators lead to different current and basic costs in the production of compressed air and its transportation. The cost components for each of the schemes are shown. The three basic types of compressed air generators are discussed here: a stationary compressor station located on the earth's surface (CS); mobile compressor stations (MCS), and pressure boosters (PB) installed near the consumption sites.

On the production and use of compressed air in mining operations

On the production and use of compressed air in mining operations