Process control for recycled asphalt pavement drum plant
First Claim
1. A method for controlling the production rate in a drum plant for producing asphalt from recycled asphalt pavement comprising the steps of:
- sensing the tons per hour (TPHa) being produced by said plant;
comparing said tons per hour (TPHa) with a desired tons per hour (TPHd);
sensing drum inlet gas temperature (TDI) when (TPHd) is less than (TPHa);
comparing said drum inlet gas temperature (TDI) to a maximum drum inlet gas temperature (TDImax);
increasing the drum inlet gas temperature (TDI) when the drum inlet gas temperature (TDI) is less than the drum inlet gas temperature maximum (TDI max), andincreasing the tons per hour (TPHa) when the drum inlet gas temperature (TDI) is increased.
1 Assignment
0 Petitions
Accused Products
Abstract
A process for the production of hot mix asphalt (HMA) by the treatment of virgin material alone or adding reclaimed or recycled asphalt pavement (RAP) (up to 100% of the HMA). The HMA is first heated in either a parallel or a counter flow rotating drum which is supplied with hot combustion gases generated by a remote low NOx burner. The process is controlled by a micro-processor which controls RAP temperature, mixture gradation, emissions and production rate as a function of measured drum conditions such as temperature at the drum inlet, drum speed, drum slope, drum RPM, output hydrocarbons, drum gas outlet temperature, and amount of aggregate added.
-
Citations
14 Claims
-
1. A method for controlling the production rate in a drum plant for producing asphalt from recycled asphalt pavement comprising the steps of:
-
sensing the tons per hour (TPHa) being produced by said plant; comparing said tons per hour (TPHa) with a desired tons per hour (TPHd); sensing drum inlet gas temperature (TDI) when (TPHd) is less than (TPHa); comparing said drum inlet gas temperature (TDI) to a maximum drum inlet gas temperature (TDImax); increasing the drum inlet gas temperature (TDI) when the drum inlet gas temperature (TDI) is less than the drum inlet gas temperature maximum (TDI max), and increasing the tons per hour (TPHa) when the drum inlet gas temperature (TDI) is increased. - View Dependent Claims (2, 3, 4)
-
-
5. A method for controlling the emissions from a drum plant for producing asphalt from recycled asphalt pavement comprising the steps of:
-
sensing hydrocarbons in drum plant exhaust (VOC); comparing VOC to maximum hydrocarbons allowed VOCmx; sensing drum slope (DS) when VOC is greater than VOCmx; comparing the drum slope (DS) to a drum slope minimum (DSmn); and decreasing DS, and increasing tons per hour (TPH) when DS is greater than DSmn. - View Dependent Claims (6, 7)
-
-
8. A method for controlling the gradation in the product of a drum plant for producing asphalt from recycled asphalt pavement (RAP) comprising the steps of:
-
sensing the gradation of the mix (GRAD); comparing the gradation of the mix to a gradiation of the mix desired GRADd; sensing gas volume out of the drum (GASo) when GRAD is greater than GRADd; comparing the gas volume out of the drum (GASo) to a maximum gas volume out of the drum (GASomx); and increasing GASo when GASo is less than GASomx. - View Dependent Claims (9, 10)
-
-
11. A method for controlling the recycled asphalt pavement (RAP) outlet temperature in a drum plant for producing asphalt from recycled asphalt pavement comprising the steps of:
-
sensing the outlet temperature of the RAP (Tr); comparing the outlet temperature of the RAP (Tr) to the temperature of the RAP required (Trd); sensing the drum inlet gas temperature (TDI); comparing the TDI to a maximum drum inlet gas temperature (TDImx) when Tr is less than Trd; increasing the drum inlet gas temperature (TDI) when TDI is less than TDImx; sensing the gas volume out of the drum (GASo); comparing the gas volume out of the drum (GASo) to a maximum gas volume out of the drum (GASomx) when TDI is not less than TDImx; and increasing the gas volume out of the drum (GASo) when the gas volume out of the drum (GASo) is less than GASomx. - View Dependent Claims (12, 13, 14)
-
Specification