BioProcess TEA

BioProcess TEA Calculator

Tutorials

Calculator Overview

A TEA begins with, and is specific to, the details of the process being modeled. For bioprocesses, a plant can be divided into upstream and downstream areas. Upstream areas are related to fermentation, which can be either aerobic or anaerobic. The current version of this calculator is focused on aerobic fermentation. Downstream areas are related to product purification. Product purification methods depend on the physical and chemical properties of the product, and also on other factors, like purity requirements. The series of unit operations required for purification will, however, be similar for any given product chemistry (i.e. polyols, organic acids, amino acids). The cost estimation techniques used in this model have an expected accuracy of +/- 30 to 50%. Missing process steps or equipment is the most common source of error in early-stage cost models.

How to use this App ( Jump to Video Tutorials)

In the menu to the left, the user can modify settings for a number of the process and financial parameters. The default values are based on publicly available data and literature. For key process metrics the user can examine base-, expected-, and worst-case scenarios. As an early-stage development tool, a model like this is intended to give technology developers (1) an indication of current economic performance based on their demonstrated process metrics, (2) target process metrics needed to achieve a desired economic performance, and 3) an understanding of the relative importance of the various process metrics.

Use Cases and Limitations

Use Cases

New Construction : This calculator should be used for projects requiring the construction of new dedicated plants for the production of chemicals using bioprocesses. Estimates of capital costs for new plant construction are based on brownfield assumptions. (See below). With this calculator, the minimum annual production capacity considered for a new facility is 1kta ( 1 kilotonne per annum/year) or alternative 1,000,000 kg of a chemical product per year. Processes resulting in annual production volumes lower than this should not use these estimates. Additionally, for products at the low end of these production volumes, contract manufacturing (leveraging existing facilities, rather than building a new plant) may be commercially viable. The current version of this calculator assumes new construction.

Production Volumes: As mentioned this calculator should be used for processes producing anywhere from 1 to 100kta of a chemical. This equates to 1,000,000 to 100,000,000 kg per year. The use should assess whether the volumes considered by this calculator are meaningful in light of the market size for a given product. For example, if the current worldwide annual production is lower than 1 kta , this calculator is likely not appropriate.

Brownfield Site Development: It is important to note that the current capital cost estimates are for Brownfield site develop. This assumes that the plant is constructed on a site with current access to a larger waste water treatment facility and basic utilties such as natural gas and electric power. The costs to install process level utilities ( those needed for specific process unit operations including steam, air, water) are included as well as initial waste processing.

Product Types: The current version of the Bioprocess TEA calculator enables users to evaluate the biosynthetic production of a wide variety of organic chemicals. Currently products are limited to those containing carbon, hydrogen, oxygen and nitrogen atoms. There is currently no support for chemicals with a wider variety of functional groups such as those containing sulfur or other heteroatoms. This functionality may be added in the future.

Current Limitations

Sugar Sources: The current version of the calculator assumes glucose (dextrose) as the carbon and electron source for the production of any given target chemicals. Future variants may include additional feedstocks. Please feel free to request a new feedstock in the discussion board.

Downstream Purification: Currently, the calculator estimates the costs associated with primary cell removal. These costs are standard in most bioprocesses, whether the product is in the supernatant or the cell pellet. However, as of today, the calculator only enables the user to estimate additional DSP operating and capital costs as a fraction of total costs without any detailed estimates of these unit operations. The vast diversity of potential DSP unit operations may be added at a later date or upon request. Generally we would recommend the following assumptions for estimating DSP costs.

Importantly, the current estimates assume a single byproduct: carbon dioxide. All dextrose not going to produce biomass or product is completely oxidized to carbon dioxide. In most cases this likely overestimates the oxygen requirements of the process and represents a worse case scenario with respect to aeration, this represents a best case scenario with respect to DSP. Real world downstream purification processes must often deal with the removal of several unwanted organic byproducts, which are function of the product and biosynthetic pathway, as well as strain and conditions used.

Capital costs for DSP can range from 20% of the TIC to over 80% depending on the complexity of the DSP and number of unit operations. Simple distillation, such as is used for ethanol, may be on the lower end (~ 20%), whereas DSPs requiring chromatographic separations or electrodialysis would be anticipated to account for 50-70% of the TIC.

Operating costs for DSP are often a smaller fraction of the total percentage of OPEX, and we recommend from 10% at the low end to 40% at the high end.

The default values for DSP of 20% of OPEX and 20% of CAPEX are recommended when the user does not have a specific downstream in mind.

Product Acidity/Basicity: Currently the calculator does not account for product acidity or basicity. Specifically it assumes the product will have a pKa ~ 7.0, and that the pH of the fermentation is held constant at neutral pH. This means that for products which are acids and/or bases the model does not account for the costs of the titrants needed for neutralization, although capital estimates for titrant delivery are included. While future iterations of the calculator may include these estimates based on user input pKas, currently, if necessary, the user can estimate the worst case scenario by assuming one mole of base or acid required per mole of product produced in the facility. Default ammonia prices of $0.12/lb ($0.000264/g) correlates to ~ $/0.0045/mole of base. Currently, I would recommend a sulfuric acid price estimate of $150/tonne ($0.000150/g) correlates to ~ $/0.0074/mole of acid. In the even that the uncharged form is desired after purification, the user can estimate a worse case scenario where an equivalent amount of both acid and base are needed in the process, for example 1 mole of base needed per mole of product in the fermentation to maintain a neutral pH and 1 mole of acid in the DSP to convert the salt form of the product to the neutral form. In the example case of 50 kta facility producing acrylic acid (MW = 72.06g/mole), these calculations would estimate an additional annual titrant cost of $8,257,000 or $0.16/kg or $0.072/lb, which in the case of a commodity is not insignificant. Disposal of the large amount of salt waste in the DSP would also increase the relative DSP operating and capital costs.