A REVIEW OF THE COMMON CAUSES OF BOILER FAILURE IN THE SUGAR INDUSTRY
Unscheduled boiler outages in process industries are a major problem resulting not only in expensive emergency repairs, but also loss of production. This paper draws on the experience of the author's company relating to common failures of pressure parts of boilers. The paper identifies the most common types of pressure part failure and the metallurgical mechanism involved. With a knowledge of the underlying failure mechanism a number of basic causes can be identified. The paper suggests solutions that, if implemented, can reduce the incidence of unscheduled outages and thereby improve profitability.
Optimal Operations and Resilient Investments in Steam Networks
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.
A concept of general monotonicity and applications
In this paper we investigate properties of the general monotone sequences and functions, a generalization of monotone sequences and functions as well as of those of bounded variation. Some applications to various problems of analysis are given. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim