From bench scale to commercial unit
A road map for designing and commercialising novel processes
MARUTHI ETHAKOTA and KALPANA GUPTA
Technip Energies, India
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New products and processes in the market do not come straight from the lab. Instead, they cross the entire journey from proof of concept to commercial plant through lab scale, pilot scale, and many more. Every level has its significance and challenges and requires a specific skill set. The tentative range in which each step works is illustrated in Table 1.
The flow chart in Figure 1 shows a complete cycle from product demand to product supply to the market.
Some processes are developed for an environmental solution, such as waste-to-value process units and flue gas cleaning units.
Process improvement like increasing energy efficiency, process reliability, and cost saving is another driver for new process/equipment development. Equipment testing is another reason for pilot-scale units.
Lab scale proves the concept study that a product can be made from specific raw materials. The concept study is verified through laboratory experiments. The lab-scale unit’s basic flow scheme is shown in Figure 2, where materials react to produce a mixture that is further purified into product and by-product.
Typically, the lab scale arrangement provides a technical information package (TIP), including minimum information like feed product quality, yield, operating conditions, sizes of critical equipment, significant control requirement, and so on.
Technology readiness level
Technology readiness levels (TRL) are a type of measurement system used to assess the maturity level of a particular technology. Figure 3 elaborates on the various steps and their significance.
The TRL is designated to a newly developed process upon approval at a different stage. Typically, stages TRL 5 and 6 are ready for scale-up to demonstration scale.
Technology due diligence is the process of analysing and evaluating the technology to see its potential. This aligns the work of a scientist and an engineer. It is crucial to assess a technology developed at the lab scale before taking it to the demonstration scale. The basic process, mass balance, product yield, and critical equipment design developed at the lab scale are reviewed by an engineering consultant to make it consistent and continuous. Heat integration, utility interaction, and effluent identification are developed after technology due diligence.
Lab data support the proof of concept, chemical and catalyst consumption, basic flow scheme, overall mass balance, properties of the material stream, quality of product and by-product, essential unit operation, design of critical equipment, and vendor interaction for special equipment. The basic requirements for performing technology due diligence are shown in Figure 4.
The first thing to keep in mind is the demonstration plant is a scaled-down version of a commercial unit, not a scale-up of laboratory experiments. The demonstration plant step is necessary to witness process variation, process interaction, potential effluents, process control behaviour, chemical consumption, energy requirement, and the like. The information/data developed in the demonstration plant allows a better understanding of the overall process and makes the basis of a commercial plant. Moreover, hidden hurdles come alive in the demonstration unit when the process moves from lab scale to pilot scale. The transition of lab-scale technology to demonstration scale is shown in Figure 5.
Factors such as energy integration, utilities, emissions, effluent and basic critical equipment design that were missing at lab scale are considered in the demonstration scale.
All the data from the lab unit collected from the research are combined with the know-how of basic technology/concepts, which becomes the basis for the engineering activities. The research provides the design criteria for critical equipment to prepare for a scale-up demonstration unit. These data should be analysed deeply, and necessary discussion carried out with the research team before scale-up.
Demonstration scale provides data for evaluating process economics, including capital and operating costs and data for environmental clearance. Decision makers like an investor, regulator, contractor or environment clearance authority require data to approve the project, and the demonstration plant provides the data. The soundness of technology is demonstrated and showcased to the investor.
Although demonstration plants are expensive to build and operate, escaping this step while scaling a process directly to commercialisation can result in lengthy delays in commissioning the commercial plant and even commercial failure. Besides the process, the pilot unit also is used to test equipment prototypes.
The next question is: what should be the size of the demonstration plant? Material handling, investment, equipment size, and land availability are a few factors that decide the demonstration plant’s size. Simultaneously, going too small while scaling up will add risk to the commercial scale and will not serve its purpose.
Real operating environment and ambient conditions
The demonstration scale operates at real working conditions while lab-scale experiments are done in an artificial environment. Site variation and ambient conditions are tested with a wide range of process conditions and checked for environmental influences. The demonstration scale works on actual feeds, while at lab scale the feeds are usually theoretically prepared to prove the concept. For example, in a testing unit for CO2 recovery from flue gas, the gas mixture is artificially fed through gas cylinders in the lab, while at pilot scale an actual stream of flue gas from the process plant is used as feed.
The demonstration plant helps to fine-tune the process across the entire operating range and varying ambient conditions. The actual ambient conditions determine the real utility operating temperature and consumption, heat losses, winterisation requirement, and so on, whereas in the lab ambient conditions are artificially controlled.
Vendor development is one of the activities executed during the demonstration scale. First, the equipment prototype is developed and tested in the demonstration plant. Then suitable vendors are identified to build and supply equipment for the pilot/industrial unit. Scale-up of equipment in stages is better than one-time scale-up from lab level to commercial performance.
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