Power generation using independent dual organic rankine cycles from waste heat systems in diesel hydrotreating-hydrocracking and atmospheric distillation-naphtha hydrotreating-aromatics facilities

Patent metadata

Field	Value
Publication number	US-9803511-B2
Application number	US-201615087518-A
Country	US
Kind code	B2
Filing date	Mar 31, 2016
Priority date	Aug 24, 2015
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

Optimizing power generation from waste heat in large industrial facilities such as petroleum refineries by utilizing a subset of all available hot source streams selected based, in part, on considerations for example, capital cost, ease of operation, economics of scale power generation, a number of ORC machines to be operated, operating conditions of each ORC machine, combinations of them, or other considerations are described. Subsets of hot sources that are optimized to provide waste heat to one or more ORC machines for power generation are also described. Further, recognizing that the utilization of waste heat from all available hot sources in a mega-site such as a petroleum refinery and aromatics complex is not necessarily or not always the best option, hot source units in petroleum refineries from which waste heat can be consolidated to power the one or more ORC machines are identified.

First claim

What is claimed is:

1. A power generation system, comprising:
a first heating fluid circuit thermally coupled to a first plurality of heat sources from a first plurality of sub-units of a petrochemical refining system, the first plurality of sub-units comprising a para-xylene separation unit and an atmospheric distillation-Naphtha hydrotreating-aromatics plant;
a second heating fluid circuit thermally coupled to a second plurality of heat sources from a second plurality of sub-units of the petrochemical refining system, the second plurality of sub-units comprising an aromatics refining system;
a third heating fluid circuit thermally coupled to a third plurality of heat sources of a third plurality of sub-units of the petrochemical refining system, the third plurality of sub-units comprising a hydrocracking-diesel hydrotreating system;
a first power generation system that comprises a first organic Rankine cycle (ORC), the first ORC comprising (i) a first working fluid that is thermally coupled to the first and second heating fluid circuits to heat the first working fluid, and (ii) a first expander configured to generate electrical power from the heated first working fluid;
a second power generation system that comprises a second ORC, the second ORC comprising (i) a second working fluid that is thermally coupled to the second heating fluid circuit to heat the second working fluid, and (ii) a second expander configured to generate electrical power from the heated second working fluid; and
a control system configured to actuate a first set of control valves to selectively thermally couple the first heating fluid circuit to at least a portion of the first plurality of heat sources, the control system also configured to actuate a second set of control valves to selectively thermally couple the second heating fluid circuit to at least a portion of the second plurality of heat sources, the control system also configured to actuate a third set of control valves to selectively thermally couple the third heating fluid circuit to at least a portion of the third plurality of heat sources.

2. The power generation system of claim 1 , wherein the first working fluid is thermally coupled to the first heating fluid circuit in a pre-heating heat exchanger of the first ORC, and the first working fluid is thermally coupled to the second heating fluid circuit in an evaporator of the first ORC.

3. The power generation system of claim 1 , wherein the first heating fluid circuit comprises a first heating fluid tank that is fluidly coupled to the first and third heating fluid circuits and the pre-heating heat exchanger of the first ORC, and
the second heating fluid circuit comprises a second heating fluid tank that is fluidly coupled with the evaporator of the first ORC.

4. The power generation system of claim 1 , wherein the second working fluid is thermally coupled to the third heating fluid circuit in an evaporator of the second ORC.

5. The power generation system of claim 1 , wherein at least one of the first or second working fluids comprises isobutane.

6. The power generation system of claim 1 , wherein at least one of the first, second, or third heating fluid circuits comprises water or oil.

7. The power generation system of claim 1 , wherein the first ORC further comprises:
a condenser fluidly coupled to a condenser fluid source to cool the first working fluid and a pump to circulate the first working fluid through the first ORC, and
the second ORC further comprises a condenser fluidly coupled to the condenser fluid source to cool the second working fluid and a pump to circulate the second working fluid through the second ORC.

8. The power generation system of claim 1 , wherein
a first sub-set of the first plurality of heat sources comprises at least three para-xylene separation unit heat sources, comprising:
a first para-xylene separation unit heat source comprising a heat exchanger that is fluidly coupled to a PX purification column overhead stream, and is fluidly coupled to the first heating fluid circuit;
a second para-xylene separation unit heat source comprising a heat exchanger that is fluidly coupled to a PX purification column bottom product stream, and is fluidly coupled to the first heating fluid circuit; and
a third para-xylene separation unit heat source comprising a heat exchanger that is fluidly coupled to a C9+ARO stream circulated through an air cooler to a C9+ARO storage, and is fluidly coupled to the first heating fluid circuit;

a second sub-set of the first plurality of heat sources comprises at least two para-xylene separation-xylene isomerization reaction and separation unit heat sources, comprising:
a first para-xylene separation-xylene isomerization reaction and separation unit heat source comprising a heat exchanger that is fluidly coupled to a Xylene isomerization reactor outlet stream before a separator drum, and is fluidly coupled to the first heating fluid circuit; and
a second para-xylene separation-xylene isomerization reaction and separation unit heat source comprising a heat exchanger that is fluidly coupled to a de-heptanizer column overhead stream, and is fluidly coupled to the first heating fluid circuit;

a third sub-set of the first plurality of heat sources comprises at least one Naphtha hydrotreating plant heat source that comprises a heat exchanger that is fluidly coupled to a hydrotreater/reactor product outlet before a separator stream, and is fluidly coupled to the first heating fluid circuit; and
a fourth sub-set of the first plurality of heat sources comprising at least one atmospheric distillation plant heat source that comprises a heat exchanger that is fluidly coupled to an atmospheric crude tower overhead stream, and is fluidly coupled to the first heating fluid circuit.

9. The power generation system of claim 8 , wherein a first sub-set of the second plurality of heat sources comprises at least three para-xylene separation unit heat sources, comprising:
a first para-xylene separation unit heat source comprising a heat exchanger that is fluidly coupled to an extract column overhead stream, and is fluidly coupled to the second heating fluid circuit;
a second para-xylene separation unit heat source comprising a heat exchanger that is fluidly coupled to a Raffinate column overhead stream, and is fluidly coupled to the second heating fluid circuit; and
a third para-xylene separation unit heat source comprising a heat exchanger that is fluidly coupled to a heavy Raffinate splitter column overhead stream, and is fluidly coupled to the second heating fluid circuit.

10. The power generation system of claim 9 , wherein
a first sub-set of the third plurality of heat sources comprises at least seven hydrocracking plant heat sources, comprising:
a first hydrocracking plant heat source comprising a heat exchanger that is fluidly coupled to a 2nd reaction section 2nd stage cold high pressure separator feed stream, and is fluidly coupled to the third heating fluid circuit;
a second hydrocracking plant heat source comprising a heat exchanger that is fluidly coupled to a 1st reaction section 1st stage cold high pressure separator feed stream, and is fluidly coupled to the third heating fluid circuit;
a third hydrocracking plant heat source comprises a heat exchanger that is fluidly coupled to a product stripper overhead stream, and is fluidly coupled to the third heating fluid circuit;
a fourth hydrocracking plant heat source comprising a heat exchanger that is fluidly coupled to a main fractionator overhead stream, and is fluidly coupled to the third heating fluid circuit;
a fifth hydrocracking plant heat source comprising a heat exchanger that is fluidly coupled to a kerosene

Assignees

• Saudi Arabian Oil Co

Inventors

• Noureldin Mahmoud Bahy Mahmoud
• Al Saed Hani Mohammed
• Bunaiyan Ahmad Saleh

Classifications

• F01K27/00

  Plants for converting heat or fluid energy into mechanical energy, not otherwise provided for · CPC title

• C10G2400/04

  Diesel oil · CPC title

• F01K3/00 Primary

  Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein (regenerating exhaust steam F01K19/00) · CPC title

• C10G69/00

  Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process (C10G67/00 takes precedence) · CPC title

• C10G99/00

  Subject matter not provided for in other groups of this subclass · CPC title