Pm Pelagagge

Analysis of heat recovery in gas-solid moving beds using a simulation approach

This work represents a first contribution to a research programme directed towards the optimization of heat recovery from moving beds running under unsteady-state conditions. A simulation model able to represent the gas-solid bed behaviour for different operating parameters and design choices has been presented. The approach has been detailed with reference to the air-cooled bed of a sintering plant for blast furnace feeding. The sintering cooler of the Taranto Ilva steel plant, in particular, has been examined. The results of the model provide useful indications for the design and management of the heat recovery system.

Comparing heat recovery schemes in solid bed cooling

Interesting perspectives are shown by heat recovery from beds of particulate solids which have to be cooled for process requirements. Sinter making plants for blast furnace feeding represent a typical application area where energy saving policies are very attractive. With reference to a sinter cooling bed of the Ilva steel works located in Taranto, several heat recovery schemes were presented under the hypothesis of unsteady-state operation. Assuming both uniform and non-uniform cooling air flow rates, solutions based on single and double (parallel or series) hoods were characterized in terms of arrangement, control criteria and performance. Finally, a comparison analysis was carried out based on plant complexities and benefits of examined heat recovery schemes.

Optimization criteria of heat recovery from solid beds

Heat recovery from beds of particulate solids that are cooled for process requirements is an attractive practice in many industrial areas. In this paper several heat-recovery arrangements are analyzed under the hypothesis of unsteady-state operation. Assuming a constant and uniform cooling air flow rate, solutions based on single- and double- (parallel or series) hoods have been considered. Results show that significant improvements over a single hood can be achieved with double-hood systems, especially if the second hood is used as a source of preheated air. The improvements are in terms of heat-transfer efficiency and in terms of control flexibility to match the actual running conditions.

Computer integrated manufacturing in small companies: a case study

A methodology for introducing computer integrated manufacturing (CIM) technology in small companies has been developed. With the aim to assess the capabilities in real applications of the proposed approach, a case study is presented in this paper. The case study refers to a small Italian company (Italpneumatica Sud) producing pneumatic components under one of the leading trademarks in the world (SMC). Results of first experimental tests demonstrate ability of the developed methodology in improving overall company performances, maintaining at the same time low implementation costs.

Heat recovery from moving cooling beds: transient modeling by dynamic simulation

Heat recovery from moving beds of solid particulate that have to be cooled for process requirements is usually carried out by one or more hoods collecting the cooling air fed underneath the bed. However, in many process plants the bed operation is characterized by continuous variations of solid inlet temperature and flow rate. As a consequence, the design of the heat recovery plant is usually performed by assuming a hypothetical steady-state operation and resorting to mean values of the process parameters. Sizing optimization of the air capturing hoods becomes difficult to perform under such circumstances, resulting in poor performances of the whole heat recovery plant from the economical standpoint. Furthermore, control system design appears particularly critical especially for more complex heat recovery schemes. With the aim to make a contribution towards the modeling of the real-time behaviour of the cooling bed, in this paper a dynamic simulation approach has been developed based on two-dimensional schematization and on time-dependent convective-conductive heat transfer. The model enables the transient analysis of the cooling bed operation and could be used as a useful tool in control and optimal design studies. In this work reference has been made to the cooling section of an iron-ore sintering bed of the Ilva steelworks in Taranto for operating conditions definition and model verification.

Critical aspects in multi‐robot co‐operation

Outlines current research into multiple co‐operative robots and discusses the practicality of a set of experiments developed to study robot applications better and to verify different solution methodologies. Looks at the design criteria for co‐operating robot systems and describes the laboratory set up to study them.

Integrated Geographical Information System(GIS) For Urban Solid Waste Management

The general architecture of a GIS-based software tool for computer aided design of urban solid waste management systems is presented. In particular, the developed software assists the user during the planning phase of separate waste collection, including waste generation forecasting, logistics, vehicle routing issues and economic analysis. An important feature of the model is its ability to calculate realistic waste generation rates and distribution starting from geographical and population density information. Moreover, it provides rapid interactive analyses of alternative management scenarios for decision makers.

Polyfunctional plants for industrial waste disposal: A case study for small enterprises

Abstract Waste production represents a very critical problem for small enterprises which have to take charge of disposal activities and their related costs but cannot afford autonomous solutions owing to technical and financial constraints. For this kind of enterprise, polyfunctional plants appear to be one of the most promising solutions that show ability in the treatment and disposal of a wide range of wastes, performing collection and storage tasks too. At the same time, such plants allow stricter environmental control, an increased reuse of both waste materials and energy and, finally, lower capital and operating costs. In this paper a case study referring to small and very small enterprises in the Rome industrial area is presented. After characterization of the reference scenario, leading to an annual amount of about 165000 tons of waste to be treated, the technoeconomic feasibility study of the plant has been carried out. Overall economic evaluation indexes and risk analysis of the investment are also presented.

Economic impact of electrostatic precipitators pulse energization on dedusting in iron‐ore sintering plants

Investigates the application of the up‐flow anaerobic sludge bed (UASB) reactor for the anaerobic treatment of sewage sludge containing high concentrations of soluble and insoluble sulphides. Assesses the reactor’s performance in terms of volatile organic matter (VOM) and biogas production rate. The average percentage removal of VOM, total sulphide and biogas for the reactor operation without sulphide was 67 per cent, 65mgS/L and 1 L/day, respectively. The corresponding average percentage removal of VOM, total sulphide and biogas production rate for the experiment with 800mgS/L soluble sulphide was 45 per cent, 450mgS/L and 0.7L/day. Equilibrium concentrations of soluble sulphide up to 200mgS/L exert insignificant toxic effects, but toxicity increases as the concentration of soluble sulphide increases. A concentration of soluble sulphide of 1,200mgS/L produces severe toxic effects and the complete termination of gas production. An inhibitory concentration of sulphides affects gas production first, while significant volatile acid accumulation takes place much slower, and only after gas production has been severely retarded. Insoluble sulphide has an insignificant effect on the UASB up to a concentration of at least 800mgS/L. The addition of iron as ferric chloride prevents the toxicity of soluble sulphides as indicated by the minor effect on gas production. Therefore, the use of iron to precipitate sulphide could be used on a continuous basis to reduce sulphide toxicity.

Polyfunctional plants for industrial waste disposal: Capacity analysis

Abstract A major problem in polyfunctional plant planning concerns the search for the optimal treatment capacity in relation to the input waste mix. The capital intensive nature of polyfunctional plant projects needs, in fact, careful evaluation analyses to help investors to make wise economic decisions. In this paper a polyfunctional plant capacity analysis has been carried out, aimed to highlight the effect on investment profitability and to identify the optimal plant size. In this way a treatment capacity has been recognized which is able to pursue best values for all the considered evaluation indexes. Generally speaking an unequivocal optimal plant size occurs, which corresponds, in the examined scenario, to an incoming waste stream of about 300000 ton/year. As a result, the polyfunctional plant planning problem may be effectively faced by adopting capacity analysis as a methodological approach.