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Download White Papers                  Released: Aug 15, 2008               Becoming Green Fuel Biodiesel Production Testing Software VAR or Developer

Needs Assessment
Biodiesel production, whether on limited or commercial scale, entails determination of several real-time values of stream components substances for the purposes of feeds controls. The biodiesel production processes are of two types: Without esterification reaction and with esterification reaction. The documented commercial biodiesel production process based strictly on transesterification reaction - esterification within this process can also be effected with the substitution of the transesterification reactor with the combined esterification-transesterification reactor - serves a good bases for assessing the production testing needs, from which the software specification can be elicited.

Starting off with the straight transesterification biodiesel process, the operation of the process, certain data are deemed constant, being design specifications and such include

• inlet moles of carboxylic acids ( oil in gram-moles),
• inlet gram-moles of alkoxide based on the reaction
• methanol/ethanol purity

In this particular case the carboxylic acids or the oil-types making up the oil - from algae a single source - are not going to vary by much, and consequentially the hydroxide inlet gram-moles also. water in the oil is not tested because the design forces the boiling off of water.

However, depending on the processing of the oil, the oil may contain very slight free fatty acids, FFA, and the oils may no longer be all of the same type, in which case testing is required. Tests therefore will now be made for Free fatty acids. This test is to determine the extra hydroxide loading to react away the FFA.

The next series of test come about after the transesterification reaction; these include determination of the of the concentration of hydroxide in the biodiesel and glycerol and determining from it the quantity of reaction quencher needed to quench the reaction.

Post distillation, the quantity of methanol in the biodiesel and glycerol is next evaluated to enable an informed recycle or not processing, after which a wet washing is performed to remove reaction quench products and soap; and then soap analysis is performed.

Finally the post water-free washing separator effluents - expected to be final product biodiesel - is sampled for compliance with the ASTM standard specifications for biodiesel. Of course, the specification will vary depending on the country of production, in which case the comparison should be made with the specifications of that country .

Program Method
On the basis of the delineated production process needs, clearly the program method for testing the biodiesel must deploy several equipment that will perform the tasks in the sequence listed in Figure 1. While the above set of tasks is a single set operation, a producer may opt to have the set of tasks performed repeatedly for any desired number of times. Such repetition may be to enable statistical analysis of the data for a media evaluation, it may be for the purposes of testing repeatability and reproducibility analysis. Of course in the event that multiple testing is opted for, then the sampling method will change somewhat to extract larger quantities

     Figure 1. Lists of Tests for Biodiesel Production

     Pre-Reaction Tests:

• Acquire oil from stream or Storage Tank
• Inject oil into Gas chromatograph
• Obtain reading from GC in electronic data
• Relay data to computer for computation of required hydroxide concentration: design specified quantity plus FFA-to-soap conversion quantity,
• Computer relays hydroxide feed data to pump control servo-mechanism controller to pump-in just the correct amount of hydroxide into the transesterification reactor

     Post Reaction Tests:

• Measure the pH of the reaction effluent
• Relay the data to the reaction quencher to pump in enough reaction quencher substance

     Post Distillation and Wet Washing:

• Take sample of biodiesel for soap concentration analysis
• Inject sample into Gas Chromatograph
• Obtain reading from GC in electronic data
• Relay data to computer for evaluating adsorption fronts analysis to determine Clean Front within design specified bounds inside the packed bed water-free washing separator

     Final Product:

• Take sample of biodiesel for full components analysis
• Inject sample into Gas Chromatograph
• Obtain reading from GC in electronic data

Specifications Development
The software developed to support the above production testing program must clearly be at the very least a Client/ Server Software supported with a relational data base.

The Client Software actually should be a collection of software pieces, one for each of the instruments that interfaces with the process streams such as:

 Table 1. List of Client Applications

additional instrumentation may be required and should such be the case then more clients may have to be provided.

The Server Application must be multi-threaded with Inter-Process Communications and support virtually pervasive data exchange. At a minimum, a thread should be provided for each of the pairwise Program Method sets given in the Table 1; other data management software pieces as necessary may then be included for completion.

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