Scale-Up Processes

Iterative Methods for the Chemical, Mineral and Biological Industries

Jamal Chaouki, Rahmat Sotudeh-Gharebagh, Jamal Chaouki, Rahmat Sotudeh-Gharebagh

• Editorial: De Gruyter
• Año: 2021
• ISBN:
  9783110714135
• Edición: 1
• Categoría: Tecnología e ingeniería
• Categoría: Ingeniería química y bioquímica

Common scale-up methods are conventional where the blind piloting is essential. This imposes huge investment and leads to failures mostly in solid processing. However, the limitations of resources, current shortcomings, short time-to-market demand are forced companies to minimize piloting. With these situations in mind, current digitalization outlook and computational facilities, we proposed and developed a novel iterative scale up method with case studies which highly expedites the process innovation through the following key sequences:

1 Conventional scale-up method: challenges and opportunities

Rahmat Sotudeh-Gharebagh

School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran

Jamal Chaouki

Department of Chemical Engineering, Polytechnique Montréal, Canada

Abstract

This chapter covers the application of scale-up in chemical process industries, which has been the core of certain industrial successes where the size of the pilot plants was large enough to allow for an appropriate extrapolation of the processes. The design and operation of the pilot plant are therefore central to its success. Nonetheless, the limitation of monetary resources has forced companies to substantially decrease the size of pilots and that has created a knowledge gap between these units and the industrial-scale units leading to process failure. There are, however, some challenges and opportunities surrounding the conventional scale-up. Statistical data reported in this chapter show the importance of taking a fresh look at pilot plants and ways to replace them for future scale-ups. The proper design and use of scaled-down pilot plants, process simulation, and a return to lab experiments would be considered alternative solutions to pilot plants in the path of conventional scale-up. With the information reported in this chapter and the power of information technology, it seems, in some cases, we can avoid piloting before design, and other tools can be employed for the benefit of scale-up to a large extent.

Keywords: scale-up, pilot plant, start-up index, failure, extrapolation, scaled-down pilot, process simulation,

1.1 Introduction

The history of scale-up goes back to canned food consumption in the British Royal Navy in 1845 [1]. Sometime later, an outbreak of food poisoning was reported due to the use of larger cans where the heating was not sufficient in killing the bacteria in the middle of the cans. Using a conventional definition, scale-up in chemical engineering means the migration of a process from the laboratory scale to the pilot or industrial scale through similarities, process design, and scaling rules. Several excellent books and documentation are available in the literature to address the chain of the scale-up process systematically, to present various techniques for obtaining scaling rules, dimensionless groups and relations on fluid flow, heat and mass transfer, and chemical reactors, and to provide typical parameters for design and geometric scale-up [2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. In some literature, scaling rules are classified as proportional similarities, for example, geometric similarity with dimensions, mechanical similarity with material deformations, thermal similarity with temperatures, and chemical similarity with concentrations [12]. Perry’s Chemical Engineering Handbook provides a detailed analysis of dimensionless groups, scaling law, and relationships and could be very instrumental in scale-up [13]. One must be careful about the dependent or independent parameters to be scaled, for example, kinetics can be directly extrapolated to other types of reactors because it depends only on the nature of the support and active phases of the catalyst [10], while hydrodynamics, heat transfer, fluid flow, and so on can be dependent on the scale.

The chemical process design has progressed rapidly since Ernest E. Ludwig first published his famous three-volume series on Applied Chemical Process Design for Chemical and Petrochemical Plants some 60 years ago followed by two further revisions some 20 years later. These provide design procedures on suitable equipment to practicing engineers for selecting an application. With Ludwig’s passing, Coker has continued the work with a significantly expanded and thoroughly updated version of Ludwig’s works and he developed programs and made enormous contributions [14, 15, 16]. Various equations, correlations, and scaling laws are reported in the books and are of great importance for the designer. The conventional scale-up method has therefore been the core of certain industrial successes in building large plants in the chemical process industry (CPI) and various failures during the last decade helped improve the design enormously. However, in successful scale-ups, the sizes of the pilot units were large enough to allow for an appropriate extrapolation; otherwise, they cannot serve confidently to demonstrate the scalability of a process.

The pilot plant experiments should provide more than a single data point. The experiments should also help generate more data on the critical effects of important parameters on scale-up. Today, the conventional scale-up method is facing two major dilemmas: first, the process designs are becoming very tight in order to minimize the expenditures of the industrial project; and second, business owners have been pushing the designer to substantially decrease the size of the pilots or replace it with an e-pilot due to the limitation of monetary resources. These two dilemmas have created a knowledge gap in scale-up and a new approach is needed to fill this gap. With the new scale-up, the use of existing correlations or scaling rules should be revised in order to expand their applicability to process design, and proper scaling rules should be proposed to be consistent with changes in the type of piloting or its replacement with other means. This chapter therefore provides an overview of the conventional scale-up method by providing some details on the basics, start-up issues, challenges, opportunities, and learning points.

1.2 Terminology

As in other engineering fields, specialized terminology is used in scale-up as defined below:

• CAPital EXpenditure (CAPEX): Funds used by a company to acquire, maintain, and upgrade physical assets, such as technology, equipment, plant, property, and buildings. It is an expense a firm incurs to create a benefit in the future.
• Chemical process industries (CPIs): Industries in which the feedstocks are chemically/physically converted into finished products. These broadly include: the traditional chemical industries, both organic and inorganic; the gas, petroleum, and petrochemical industries; fine chemical and pharmaceutical industries; and a series of allied industries in which chemical processing takes place.
• Conventional scale-up method: Migration of a process from the laboratory to the pilot and/or industrial scale. In some literature, the term of “single-train” scale-up is also used and refers to the conventional scale-up method.
• Independent project analysis (IPA): A benchmarking and consulting firm devoted to the empirical research of capital investment projects to maximize business value and project effectiveness. (https://www.ipaglobal.com)
• Industrial disaster: A disaster rooted in the products or processes of an industry as a result of an accident, incompetence, or negligence. This could lead to significant damage, injury, or loss of life.
• Iterative scale-up: Migration of a process from the laboratory to industrial scale, and coming back to either the laboratory scale, pilot scale, cold scale, or process modeling scale is essential to improve the key characteristics of the industrial-scale design.
• OPerating EXpenditure (OPEX): Expenses required for the day-to-day functioning of a business.
• Pilot scale (pilot plant): Small-scale system, which is operated to study the behavior of a process before using it on a large industrial scale. This is an important system and central for risk identification before the production takes place at the full industrial scale.
• Process design: Designing and sequencing of unit operations for desired physical and/or chemical conversions/purifications of feedstocks into products. It is instrumental to the process scale-up and the summit of chemical engineering, bringing together all the relevant knowledge and components.
• Process simulation: A model-based representation ...