Comparison of Saturated and Superheated Steam Plants for Waste-Heat Recovery of Dual-Fuel Marine Engines

Abstract

From the working data of a dual-fuel marine engine, in this paper, we optimized and compared two waste-heat-recovery single-pressure steam plants—the first characterized by a saturated-steam Rankine cycle, the other by a superheated-steam cycle–using suitably developed simulation models. The objective was to improve the recovered heat from the considered engine, running with both heavy fuel oil and natural gas. The comparison was carried out on the basis of energetic and exergetic considerations, concerning various aspects such as the thermodynamic performance of the heat-recovery steam generator and the efficiency of the Rankine cycle and of the combined dual-fuel-engine–waste-heat-recovery plant. Other important issues were also considered in the comparison, particularly the dimensions and weights of the steam generator as a whole and of its components (economizer, evaporator, superheater) in relation to the exchanged thermal powers. We present the comparison results for different engine working conditions and fuel typology (heavy fuel oil or natural gas).

Optimisation of a Diesel-Electric Ship Propulsion and Power Generation System Using a Genetic Algorithm

“…P el (X) ≥ n p P EPM + P aux (10) where P aux the power required to satisfy the auxiliary services. Note that this should be an equality constraint: the power provided by the generation system in its working conditions should instantly match the power load.…”

“…The latter makes traditional propulsion the most proficient choice for those marine units characterised by relatively narrow operating profiles, i.e., those ships that steam most of the time at their design speed. Combined propulsion plants [7][8][9][10] coupled with controllable pitch propellers can match the operating requirements of ships that require more flexible profiles, for instance, ferries that steam at a different speed in winter or summer season or for navy vessels.…”

Energy Optimization Based on Steam System Analysis and Waste Energy Recovery for Iron and Steel Industry

“…[ 29 ] In I&S enterprise, the amount of medium‐grade (MG) and low‐grade (LG) waste energy is huge as shown in Figure 1 , but the recovery and utilization of it do not achieve effect. [ 30 ] Organic Rankine Cycle (ORC) [ 31–33 ] and saturated steam power generation (SSPG) [ 34 ] could effectively solve the issue of MG and LG waste energy recycling and utilization for power generation. In order to further optimize the recycling effect of energy, researchers developed a series two‐stage Organic Rankine Cycle (STORC) based on ORC, which further strengthened the recycling of waste energy.…”

Energy, Economic and Environmental Effects of the Marine Diesel Engine Trigeneration Energy Systems

“…The waste heat capacity potential of the typical stationery and marine engines is analyzed in [12,13], where it is concluded that this part of the energy also has potential for trigeneration purposes. The improvement of the waste heat recovery from marine diesel engines with the best fulfilment of the vessel needs in terms of mechanical, electric and thermal energies is analyzed in [14,15], where various solutions are proposed, with combined diesel engine, steam and gas turbines recovering part of the thermal energy of the diesel engine exhaust gas. The similar approach of feedwater regeneration to the boiler from the marine engines was presented in [16], which also concluded that waste heat will beneficially contribute to the efficiency of waste heat recovery.…”