Optimal Operations and Resilient Investments in Steam Networks

Abstract

Steam is a key energy vector for industrial sites, most commonly used for process heating and cooling, cogeneration of heat and mechanical power as a motive fluid or for stripping. Steam networks are used to carry steam from producers to consumers and between pressure levels through letdowns and steam turbines. The steam producers (boilers, heat and power cogeneration units, heat exchangers, chemical reactors) should be sized to supply the consumers at nominal operating conditions as well as peak demand. First, this paper proposes an Mixed Integer Linear Programing formulation to optimize the operations of steam networks in normal operating conditions and exceptional demand (when operating reserves fall to zero), through the introduction of load shedding. Optimization of investments based on operational and investment costs are included in the formulation. Though rare, boiler failures can have a heavy impact on steam network operations and costs, leading to undercapacity and unit shutdowns. A method is therefore proposed to simulate steam network operations when facing boiler failures. Key performance indicators are introduced to quantify the network's resilience. The proposed methods are applied and demonstrated in an industrial case study using industrial data. The results indicate the importance of oversizing key steam producing equipments and the value of industrial symbiosis to increase industrial site resilience.

Energy and Environmental Assessment of Steam Management Optimization in an Ethylene Plant

“…Around 40% of industrial emissions can be attributed to the production of energies and media consumed in production processes [3,4]. Electricity and steam production, distribution, and consumption systems are ideal candidates for design and operation optimization [5,6] within the scope of energy management systems implementation [7,8]. The drivers of such activities include several technical and nontechnical aspects, such as sustainable industrial production [9][10][11], labeling of products as 'green' [12], increasing price of carbon emissions [13,14], as well as the persistent need 2 of 17 for an increase in production efficiency [15] to remain innovative and competitive on the market [16,17] and to comply with the legislation [18].…”

“…Considering the refining and petrochemical industry, individual production units are typically assembled in organized production groups, refineries [34], that can be a part of even larger chemical complexes and industrial parks [35,36]. Typically, three to five main steam pressure levels satisfy the needs for delivered steam quality [6]. CHPs are commonly equipped with several steam boilers producing high-pressure steam and several steam turbines to cope with the varying demand for steam at individual pressure levels [37].…”