Methods and apparatus for treating bitumen mixtures

A method, comprising:

• pre-heating, using a first heat exchanger, a low-viscosity bitumen composition,
• wherein the low-viscosity bitumen composition has a first viscosity and comprises bitumen and a diluent;
• pre-heating, using a second heat exchanger in fluid communication with the first heat exchanger, the low-viscosity bitumen composition;
• separating, using a fractionator in fluid communication with the second heat exchanger, the pre-heated low-viscosity bitumen composition into:
• a first heavy fraction having a first temperature, and
• a first light fraction having a second temperature that is greater than the first temperature and thus the first temperature of the first heavy fraction is less than the second temperature of the first light fraction;
• lowering, using the first heat exchanger, the first temperature of the first heavy fraction;
• lowering, using the second heat exchanger, the second temperature of the first light fraction;
• wherein the low-viscosity bitumen composition is pre-heated using the first heat exchanger, with which the first temperature of the first heavy fraction is lowered, before the low-viscosity bitumen composition is pre-heated using the second heat exchanger, with which the second temperature of the first light fraction is lowered;
• wherein the first heat exchanger uses cross-flow heat exchange to:
• lower the first temperature of the first heavy fraction at the step of lowering the first temperature of the first heavy fraction using the first heat exchanger;
• and
• pre-heat the low-viscosity bitumen composition at the step of pre-heating the low-viscosity bitumen composition using the first heat exchanger;
• wherein the second heat exchanger uses cross-flow heat exchange to:
• lower the second temperature of the first light fraction at the step of lowering the second temperature of the first light fraction using the second heat exchanger;
• and
• pre-heat the low-viscosity bitumen composition at the step of pre-heating the low-viscosity bitumen composition using the second heat exchanger;
• wherein the first heavy fraction is or forms a high-viscosity bitumen composition having a second viscosity that is higher than the first viscosity of the low-viscosity bitumen composition;
• and
• wherein the method further comprises directing the high-viscosity bitumen composition to a railcar for transportation of the high-viscosity bitumen composition over a railway so that, during the transportation of the high-viscosity bitumen composition over the railway, the high-viscosity bitumen composition has:
• a flash point of greater than or equal to 93 degrees Celsius;
• and
• at least two volume percent of components from the diluent of the low-viscosity bitumen composition.