Asphalt Plants

Process Viscometer Application Data Sheet

Application

Brookfield's TT-100® in-line viscometers are ideal solutions for monitoring and controlling asphalt production at oil and gas refineries worldwide. Rugged and dependable, the TT-100® viscometer is used to monitor viscosities during the second distillation within the vacuum tower process. Asphalt can be found in a natural state but is typically obtained as asphaltic residue in the distillation of coal tar and petroleum. In the initial refining of these oil and gas products, a heating process results in the distillation of natural gas, gasoline, kerosene, diesel gas oil, and at the bottom of the distilling tower is the remaining asphalt or tar residue. This asphalt residue is then admitted to a second refining process where it is heated under vacuum. There, it is further distilled to produce variable asphalt grades suitable for specific applications like mixtures of asphalt with sand or gravel for paving, roofing, and other products.

Problem Description

Today's modern asphalt production plants require viscosity measurement and control to save both time and money in the development of asphalt and tar products of varying grades and viscosities. Refineries make many different grades of asphalt, including: AC-5 asphalt with a viscosity of 500 cP, AC-20 asphalt at 2000 cP or AC-30 asphalt at 3000 cP. Brookfield's TT-100® inline viscometers ensure that refinery managers can handle the variable quality of delivered crude oil. Refineries typically purchase this crude oil from many diverse spot markets around the globe. These crudes differ in asphaltine concentrations and it is vital to identify crude switches during the distillation process to avoid disruption of the continuous distillation process.

Solution

The Brookfield TT-100® in-line process viscometer is required to determine crude switches and grade cuts at today's modern refineries. It ensures that no fluctuation in the asphalt viscosity grade cuts occurs. The Brookfield TT-100® solution includes the following design considerations:

• control of distillation tower operation by continuous viscosity feedback signal
• output from the viscometer instantly responds to all in-line viscosity changes
• system design will accommodate the large pressure and temperature swings associated with refinery tower operation
• recommend bypass loop for viscometer installation in order to build in redundancy for fail-safe operation

Qualifying Your Application

• Are you an oil refiner that produces asphalt and/or tar products?
• Do you still take laboratory or benchtop grab samples to ensure quality control?
• Do you use a petroleum supply purchased from different spot markets?
• If yes, are your tower operational costs increasing despite stable crude oil prices?
• Do you need to adjust tower operational parameters more often than usual?
• Is your operation a 24-hour/day continuous production?

Benefits

• Overcomes the limitations of variable composition crude deliveries
• Improves tower efficiency
• Significantly reduces quality control/quality assurance (QC/QA) labor costs
• Establishes the cut time for the various grades of asphalt during the production run
• Helps control in-line asphalt viscosity to maintain the grades required
• Users realize increased production through more efficient distillation of asphalt grades and reduced labor costs resulting from reduced need for grab sample testing to verify product
• Eliminates costs associated with the rework of bad product

References

Available upon request

Return on Investment

The use of Brookfield's TT-100® viscometer typically provides a payback of instrument cost and installation in six months to a year.