Pilot upscale

The scheme of commercial methane synthesis includes a multistage reaction system and recycle of product gas. Adiabatic reactors connected with waste heat boilers are used to remove the heat in the form of high pressure steam. In designing the pilot plants, major emphasis was placed on the design of the catalytic reactor system. Thermodynamic parameters (composition of feed gas, temperature, temperature rise, pressure, etc.) as well as hydrodynamic parameters (bed depth, linear velocity, catalyst pellet size, etc.) are identical to those in a commercial methana-tion plant. This permits direct upscaling of test results to commercial size reactors because radial gradients are not present in an adiabatic shift reactor. 

The only safe way of designing a rotary dryer is based on pilot plant tests or by comparison with known performance of similar operations. Example 9.5 utilizes pilot plant data for upscaling a dryer. The design of Example 9.6 also is based on residence time and terminal conditions of solid and air established in a pilot plant. 

A continuous counter-current reactor system has shown great promise as a process reactor in the dilute acid hydrolysis of cellulose. However, the findings on this unique reactor system have been limited to the theoretical aspects and the proof-of-concept laboratory experiments. It has to be developed into an upscale process reactor before it is adopted into the biomass conversion process. To this end, a pilot-scale process study is being conducted at NREL. This is only the first step. To be noted here is that reactors of similar design are being used in industry it took years of developmental work, however, before they were put into commercial service. It would probably take about the same degree of investment in this case. In addition to the reactor issue, there are other important issues that need to be addressed in the dilute acid process. 

Microbially catalyzed processes often have a lag time before a significant effect can be observed (Ehrlich, 1996) obviously a problem in temporal upscaling of short time experiments. Figure 13.1 shows the temporal development of sulfate and ammonium concentrations measured in wells upstream and within the pilot scale Fe reactive barrier at the Rheine site (NRW, Germany). A site description and monitoring results are reported elsewhere (Ebert et al., 1999A, B). A most probably microbially mediated sulfate reduction with subsequent sulfide precipitation accounts for the decrease in sulfate concentration within the reactive barrier over a period of several months. Sim-... 

In this chapter, we discussed the concepts of models and prototypes and presented the criteria for scaling a chemical process from a model to a prototype or from a commercial plant to a pilot plant or a laboratory. We also introduced the concepts of upscaling and downscaling in this chapter. 

An unpublished cradle-to-gate life cycle analysis (LCA) study subcontracted to Vito (Mol, Belgium) tried to identify environmental bottlenecks of rhamnolipid and sophorolipid production and compare them with those of market reference surfactants according to the ISO 1404x series. Experimental data for the pilot plant scale were complemented with LCA data from the Vito database as well as literature data for the upscaled production scenario. In order to compare the environmental profile of these biosurfactants with market reference surfactants data were used from Zah and Hischier [18]. The Eco-Indicator 99 methodology [19] was used to determine environmental impacts. 

System upscaling is the most critical need for MECs (Logan et al., 2008 Zhang and Angelidaki, 2014). Phot-scale MECs have been built to treat domestic wastewater but the energy recovery is only around 50—70% of electricity input, and hydrogen production rate as well as COD removal rate is low (Heidrich et al., 2013 Heidrich et al., 2014). Much has to been done to optimize reactor design and operational parameters in order to make pilot-scale MECs cost-effective and efficient. 

---