CN110966082A - Fan-free waste heat recovery control method for diesel engine of offshore oil production platform - Google Patents

Fan-free waste heat recovery control method for diesel engine of offshore oil production platform Download PDF

Info

Publication number
CN110966082A
CN110966082A CN201811165683.0A CN201811165683A CN110966082A CN 110966082 A CN110966082 A CN 110966082A CN 201811165683 A CN201811165683 A CN 201811165683A CN 110966082 A CN110966082 A CN 110966082A
Authority
CN
China
Prior art keywords
waste heat
heat recovery
pressure
diesel engine
efficiency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201811165683.0A
Other languages
Chinese (zh)
Inventor
刘向龙
曾丽萍
李小华
陈晓
苏欢
李文宾
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hunan Institute of Engineering
Original Assignee
Hunan Institute of Engineering
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hunan Institute of Engineering filed Critical Hunan Institute of Engineering
Priority to CN201811165683.0A priority Critical patent/CN110966082A/en
Publication of CN110966082A publication Critical patent/CN110966082A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
    • F02G5/00—Profiting from waste heat of combustion engines, not otherwise provided for
    • F02G5/02—Profiting from waste heat of exhaust gases
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)

Abstract

The invention discloses a draught fan-free waste heat recovery control method for a diesel main engine of an offshore oil production platformCEfficiency of diesel engine ηCExpansion efficiency ηDPressure holding coefficient rho of combustion process of diesel engineComWindage resistance αSAnd pressure holding coefficient rho of heat recovery process of diesel engineR(ii) a Determining the combustion temperature, the flue gas specific volume and the pressure of working medium state points at the outlets of turbines of the diesel engine according to the obtained parameters; obtaining fuel
Figure DDA0001819787550000011
E. Output electric power
Figure DDA0001819787550000012
EPEfficiency E of turbocharging for diesel engineTAnd heat output by the system
Figure DDA0001819787550000013
EQAnd finally obtaining a waste heat recovery system
Figure DDA0001819787550000014
An efficiency ε; thereby controlling the efficiency of the waste heat recovery system. Compared with the prior art, the control method provided by the invention obtains the system when the waste heat of the diesel engine is recovered
Figure DDA0001819787550000015
The relation between the efficiency and the pressure ratio parameter and the temperature ratio parameter controls the pressure of each state point parameter by observing the parameters of each state point, thereby leading the system to recover the waste heat of the diesel engine
Figure DDA0001819787550000016
The efficiency is highest.

Description

Fan-free waste heat recovery control method for diesel engine of offshore oil production platform
Technical Field
The invention relates to the field of offshore oil recovery energy recovery, in particular to a draught fan-free waste heat recovery control method for a diesel engine of an offshore oil recovery platform, and specifically relates to a method for monitoring and controlling the residual heat recovery efficiency.
Background
The middle sea oil is provided with a large number of oil production platforms and FPSOs on the offshore continental shelf, 3-5 power generation Diesel main engines with different powers are generally arranged on oil production facilities, and if the efficiency of a Diesel main engine system is improved, the recovery of waste heat of flue gas is an ideal way. Because the load of the diesel main engine changes according to the change of the oil production during waste heat recovery, the waste heat quantity of the diesel main engine is determined by the load of the diesel main engine, and therefore the working efficiency of the waste heat recovery equipment is adjusted according to the change of the load of the diesel main engine during waste heat recovery, and the waste heat utilization rate is maximized. The existing offshore oil production facility does not take the factor into consideration for waste heat recovery.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a draught fan-free waste heat recovery control method for a diesel engine of an offshore oil production platform, which can adjust the working efficiency of waste heat recovery equipment according to the load change of the diesel engine, so that the waste heat utilization rate is maximized.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
the invention provides a draught fan-free waste heat recovery control method for a diesel engine of an offshore oil production platform, which comprises the following steps of:
step S1) determining a pressure ratio parameter theta of the diesel engine according to the inlet and outlet pressure, the inlet and outlet temperature and the flue gas specific heat ratio of the gas compressor of the diesel engineCIn the waste heat recovery process, especially in the process of recovering the offshore waste heat, because of the space limitation of the offshore oil production facility, a fan is not added at the tail part of a diesel main engine generally, and the problem of the wind resistance of the waste heat recovery is solved mainly by the main engine, so the wind resistance coefficient α is also consideredS；
Step S2) determining the efficiency η of the diesel engine according to the actual outlet temperature of the compressor of the diesel engine, the outlet temperature after irreversible loss and the environment temperatureCAnd expansion efficiency ηD；
Step S3) determining pressure holding coefficients rho of the combustion process and the heat recovery process of the diesel engine according to the outlet pressure of the compressor turbine of the diesel engine, the pressure after the combustion process of the combustion chamber and the specific heat ratio of the flue gas after combustionComAnd ρR；
Step S4) according to the parameter theta obtained in the steps S1-S3C、ηC、ηD、ρCom、αSAnd ρRDetermining the combustion temperature, the flue gas specific volume and the pressure of each outlet working medium state point of the diesel engine;
step S5) determining the waste heat recovery system according to the parameters obtained in the steps S1-S4
Figure BDA0001819787530000011
An efficiency ε;
step S6) according to the diesel engine obtained in the step S5Of systems for recovering waste heat under different loads
Figure BDA0001819787530000021
The extreme value of the efficiency epsilon determines the pressure ratio parameter theta of the diesel engineCBy the pressure ratio parameter thetaCThe temperature of the outlet of the compressor turbine of the diesel main engine controls the pressure of the compressor of the diesel main engine, thereby indirectly maintaining the waste heat recovery system
Figure BDA0001819787530000022
The efficiency epsilon is the highest value.
Preferably, the pressure ratio parameter theta of the diesel engine is determined in step S1C：
θC＝T2′/T1＝(P2/P1)(γ-1)/γ(1)
Wherein gamma is the specific heat ratio of the flue gas, P1Pressure, P, for point 1 of diesel engine operating state2Pressure, T, for diesel engine operating state point 21For flue gas temperature, T, at State Point 1 during waste Heat recovery2’The flue gas temperature at the state point 2' during waste heat recovery is shown, and gamma is the specific heat ratio of the flue gas.
More preferably, the compressor efficiency η of the diesel host is determined in step S2CAnd expansion efficiency ηDThe following formula 2 and formula 3 show that:
ηC＝(T2′-T1)/(T2-T1) (2)
ηD＝(T3-T4)/(T3-T4′) (3)
in the formula, T1For the compressor turbine outlet state point 1 temperature, T2For the compressor turbine outlet state point 2 temperature, T2’For the compressor turbine outlet point 2' temperature, T3For compressor turbine outlet state point 3 temperature, T4For compressor turbine outlet state point 4 temperature, T4’The compressor turbine outlet condition point 4' temperature.
Further, the pressure maintenance coefficients ρ of the combustion process and the heat recovery process are determined in step S3ComAnd ρRThis is obtained by equations 4 and 5:
ρCom＝(P3/P2)(γ-1)/γ(4)
ρR＝(P5/P4)(γ-1)/γ(5)
in the formula, ρComFor the pressure holding coefficient of the combustion process, pRPressure holding factor, P, for heat recovery processes2For the compressor turbine outlet state point 2 pressure, P3For compressor turbine outlet state point 3 pressure, P4For the compressor turbine outlet state point 4 pressure, P5The compressor turbine outlet state point 5 pressure.
Further, the parameter θ obtained from steps S1-S3C、ηC、ηD、ρCom、αSAnd ρRDetermining the combustion temperature T, the flue gas specific volume v and the pressure P of working medium state points at the outlets of turbines of the diesel main engine through formulas 1 to 17 to enable the efficiency of the system to reach the highest value;
point 1:
P1
v1
T1
and 2, point:
P2＝(θC)γ/(γ-1)P1(6)
v2＝[1+(θC-1)/ηC](θC)-γ/(γ-1)v1(7)
T2＝[1+(θC-1)/ηC]T1(8)
and 3, point:
P3＝(ρComθC)γ/(γ-1)P1(9)
v3＝α(ρComθC)-γ/(γ-1)v1(10)
T3＝αT1(11)
and 4, point:
P4＝(ρR)γ/(γ-1)P1(12)
v4＝α(ρR)-γ/(γ-1){1-ηD[1-1/(θCρComρR)]}v1(13)
T4＝α{1-ηD[1-1/(θCρComρR)]}T1(14)
and 5, point:
P5＝P1(15)
v5＝αRv1(16)
T5＝αRT1(17)
and 6, point:
P6＝P7+ΔP (18)
Figure BDA0001819787530000031
T6＝αsT7(20)
point 7 (post-turbo state point):
P7
v7
T7
in the formula, P1-P7For pressures, v, at points 1-7 of the diesel engine operating state1-v7Specific volume of flue gas, T, at state points 1-71-T7The flue gas temperature at the state points 1-7 during waste heat recovery. The temperature and the pressure of the state point 7 are both given by a diesel engine manufacturer, generally, the tail smoke is firstly exhausted after the turbine is increased when the diesel engine operates, and if the waste heat is recovered, the waste heat is also recovered afterwards.
Then, in step S5, the fuel is determined according to the parametric expressions 1-20, 21-26 obtained in steps S1-S4
Figure BDA0001819787530000046
E. Output electric power
Figure BDA0001819787530000047
EPHeat output by the system
Figure BDA0001819787530000048
EQAnd efficiency E of turbocharging to increase hostTWherein:
Figure BDA0001819787530000041
wherein E is a fuel
Figure BDA0001819787530000049
，qmIs the mass flow of flue gas, CPη is the constant pressure specific heat capacity of the flue gascomM is the irreversible loss of fuel upon combustionhAs fuel consumption (in kg/h), QnetThe lower calorific value (kJ/kg) of the fuel;
output electric power
Figure BDA00018197875300000410
EP(kW) is calculated as:
EP＝qmCPηG[(T3-T2)-(T4-T1)](22)
in the formula, ηGThe efficiency of the generator is generally given by the manufacturer.
Heat output from the system
Figure BDA00018197875300000411
EQ(kW) is calculated as:
Figure BDA0001819787530000042
efficiency E of turbocharging to increase hostT(kW) is calculated as:
ET＝qmCPηT(T4-αST7) (24)
modification of equation 24 yields:
ET＝qmCPηT(α{1-ηD[1-1/(θCρComρR)]}T1-αST7) (25)
the equation 22 is modified to obtain:
Figure BDA0001819787530000043
system for controlling a power supply
Figure BDA00018197875300000412
The formula for calculating the efficiency epsilon is:
Figure BDA0001819787530000044
substituting the equations 23, 25 and 26 into the equation 27 to obtain the waste heat recovery system
Figure BDA00018197875300000413
Efficiency ε, can:
Figure BDA0001819787530000045
preferably, step S6 is the waste heat recovery system obtained according to S5
Figure BDA00018197875300000414
The conversion relation between the efficiency epsilon and the pressure ratio parameter and the temperature ratio parameter is obtained to obtain a relation graph, and the automatic control system of the diesel engine is used for calculating and maintaining the waste heat recovery system
Figure BDA0001819787530000051
The efficiency epsilon is the pressure of the turbine outlet of the compressor state point 2' required by the diesel engine when the efficiency epsilon is the highest value.
Compared with the prior art, the method for controlling the recovery of the waste heat of the diesel engine without the fan of the offshore oil production platform provided by the invention has the advantages that after the diesel engine expands to work, tail gas enters the turbocharger and air is introduced into the turbochargerThe pressure of (2) is increased; and a fan is added behind the turbocharger to solve the problem of wind resistance during waste heat recovery of the diesel engine. The thermal requirements of an offshore production facility are primarily to heat the crude oil by means of a hot medium boiler to maintain the fluidity of the crude oil. Therefore, the recovery of the waste heat of the engine (the diesel engine of the offshore oil production facility) arranged in the offshore oil production can be carried out in the simplest way, namely, the tail gas after turbocharging is directly heated to the heat medium system, and the crude oil is heated by the heat medium system. When the waste heat recovery process is carried out on the diesel main engine of the offshore oil production platform, the waste heat recovery process passes through a computing system
Figure BDA0001819787530000052
Efficiency, thus obtaining the system for recovering the waste heat of the diesel engine
Figure BDA0001819787530000053
The relation between the efficiency and the pressure ratio parameter and the temperature ratio parameter further controls the pressure of each state point during the waste heat recovery of the diesel engine, and controls the pressure of each state point by observing the parameters of each state point, thereby ensuring that the system during the waste heat recovery of the diesel engine
Figure BDA0001819787530000054
The efficiency is highest.
Drawings
FIG. 1 is a flow chart of a control method provided by the present invention;
fig. 2 is an irreversible simple open Brayton co-production cycle temperature entropy diagram adopted for diesel engine waste heat recovery provided by the invention.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
Thermodynamic system optimization analysis
The Brayton Cycle (Brayton Cycle) is an ideal Cycle for constant pressure heating, also known as the joule Cycle or gas refrigerator Cycle. The refrigeration cycle uses gas as working medium, the working process comprises four processes of isentropic compression, isobaric cooling, isentropic expansion and isobaric heat absorption, which are similar to the four working processes of a vapor compression type refrigerator, and the difference between the four working processes is that the working medium is not subjected to state change in the Brayton cycle. The method analyzes several thermodynamic systems, selects a simple open Brayton Cycle to analyze and optimize the waste heat recovery, and considers a diesel engine for power generation of a diesel engine as a key device in the Brayton system.
Because the whole Cycle considered by the simple open Brayton Cycle is reversible, irreversible factors such as irreversible loss of a gas compressor or combustion loss when incomplete combustion and the like need to be considered when a Brayton system is adopted for analyzing the waste heat recovery of the diesel engine, and actually, a plurality of irreversible factors exist in each oil production operation process of the offshore oil production platform, and the irreversible factors considered by the application are as follows:
(1) the internal irreversibility of the circulating working medium caused by the non-isentropic compression of the gas compressor;
(2) the internal irreversibility of the circulating working medium in the combustion chamber caused by flow loss;
(3) the internal irreversibility caused by the non-isentropic expansion of the circulating working medium;
(4) internal irreversibility of the cycle fluid in the heat recovery unit due to flow losses.
Therefore, when waste heat recovery is considered, an actual Brayton Cycle should be adopted, the dotted line in fig. 1 represents a simple open Brayton co-production Cycle process, and the solid line represents an irreversible simple open Brayton co-production Cycle process. The process of the state point 1-the state point 2 is an isentropic compression process of the working medium in the compressor, the process of the state point 2-the state point 3 is a constant pressure combustion process, the process of the state point 3-the state point 4 is an isentropic expansion process, the process of the state point 4-the state point 5 is a process that the heat of the tail gas of the diesel engine is absorbed by the waste heat recovery device, and the process of the state point 5-the state point 1 is a process that the flue gas is discharged to the atmosphere; and the state point 7 is the state point after the diesel main engine is turbocharged, and the point 6 is the temperature rise of the point 7 caused by the waste heat recovery of the waste heat boiler. Due to the compressor non-isentropic compression, after ambient air is compressed by the compressor, the outlet air state changes to point 2 and is not compressed to point 2'. Because of the flow loss, the working medium is not isobaric combustion in the combustion process of the combustion chamber, and the working medium state at the outlet of the combustion chamber is point 3 instead of point 3'. Also, due to the flow losses of the working medium flowing through the heat recovery device, the cylinder discharge pressure is no longer equal to the ambient pressure but slightly above atmospheric pressure. In addition, the irreversibility exists in the expansion process of the working medium in the turbine. Therefore, the turbine outlet working medium states are point 4 (irreversible loss exists, and the state points 1-6 represent the meaning) instead of point 4 ' (the state points when no waste heat recovery exists and no irreversible loss exists, and the state points 1 ' -7 ' represent the meaning) and point 4 ' (the state points when no waste heat recovery exists, and the state points 1 ' -6 represent the meaning).
Embodiment 1 control of waste heat recovery efficiency of marine platform diesel main engine
Taking waste heat recovery of a diesel engine of an offshore oil production platform as an example, the basic parameters of the diesel engine (i.e. a compressor, in this embodiment, a 111FPSO power generation diesel engine) are shown in table 1, and the operating parameters of the diesel engine of the power generation diesel engine are shown in table 2.
TABLE 1 basic parameter table for power generation diesel engine
Figure BDA0001819787530000061
TABLE 2 Diesel engine operating parameters (No.34024)
Figure BDA0001819787530000062
Before calculation, defining specific heat under pressure CP1.004kJ/(kg.K), constant volume specific heat CvWhen γ is 1.4, it is known that the exhaust gas temperature after turbo charging is 340 ℃.
The control method comprises the following steps:
step 1: defining the efficiency of the compressor
In the irreversible cogeneration cycle, the compression ratio of the cycle and the expansion ratio of the piston are the same, but because of the irreversible loss, the pressure ratio parameter theta of the compressor is definedC：
θC＝T2′/T1＝(P2/P1)(γ-1)/γ(1)
Wherein gamma is the specific heat ratio of the flue gas, T1The temperature of the state point 1 of the turbine outlet of the gas compressor is measured to be 30.7 ℃ in real time in the embodiment; t is2’The temperature of the state point 2' of the outlet of the compressor turbine; p1The pressure at the state point 1 of the turbine outlet of the compressor is measured, and the real-time pressure measured in the embodiment is 1.010 bar; p2The measured real-time pressure is specifically 26.05bar for the compressor turbine outlet state point 2 pressure, which in this example is the actual compressor outlet pressure.
The pressure ratio parameter theta is calculated according to the formula 1CWas 2.53.
Meanwhile, in order to characterize the irreversible loss of the compressor, the expansion sum, the compressor efficiency η is defined by the formulas 2 to 3CExpansion efficiency ηD：
ηC＝(T2′-T1)/(T2-T1) (2)
ηD＝(T3-T4)/(T3-T4′) (3)
In the formula, T1The temperature of a state point 1 is specifically 30.7 ℃; t is2The temperature T is calculated by the following equations 1, 4 and 10 as the temperature at the state point 22Is 832K; t is2’For the temperature at the state point 2', the temperature T is calculated2′768K; t is3For the temperature at State Point 3, the a value calculated according to equation 14 is 6.06, and T is calculated according to equation 1131840K taking the irreversible parameter ηD＝0.89，ηC＝0.88，ηG＝0.97，ρCom＝0.98，ρR＝0.98，T4’For the 4' temperature at the state point, T is calculated4’Was 376K.
Step 2: defining pressure retention factor
To characterize the fluidity loss of the combustion process and the heat recovery process, the pressure retention coefficients ρ are defined for the combustion process and the heat recovery process, respectivelyComAnd ρRAs shown in formulas 4 and 5:
ρCom＝(P3/P2)(γ-1)/γ(4)
ρR＝(P5/P4)(γ-1)/γ(5)
in the formula, ρComFor the pressure holding coefficient of the combustion process, pRPressure holding factor, P, for heat recovery processes3For the compressor turbine outlet state point 3 pressure, P is calculated by equation 9 in this embodiment3Is 3.6 bar; step 1 knows P226.05bar, P4P is calculated for the compressor turbine outlet state point 4 pressure by equation 1141.084bar, P5The pressure at the compressor turbine outlet state point 5 is 1.010 bar.
And step 3: determining the dot state parameters of each state of Brayton Cycle
The exhaust temperature coefficient of the waste heat recovery is assumed to be the ratio of the exhaust temperature to the ambient temperature, i.e., the waste heat recovery coefficient αR＝T5/T1And calculating the combustion temperature T, the specific volume v and the pressure P of the flue gas of each state point of the Brayton Cycle by using the parameters obtained in the steps 1 and 2 through the formulas 9 to 23, wherein the specific volume v and the pressure P are as follows:
point 1:
P1
v1
T1
and 2, point:
P2＝(θC)γ/(γ-1)P1(6)
v2＝[1+(θC-1)/ηC](θC)-γ/(γ-1)v1(7)
T2＝[1+(θC-1)/ηC]T1(8)
and 3, point:
P3＝(ρComθC)γ/(γ-1)P1(9)
v3＝α(ρComθC)-γ/(γ-1)v1(10)
T3＝αT1(11)
and 4, point:
P4＝(ρR)γ/(γ-1)P1(12)
v4＝α(ρR)-γ/(γ-1){1-ηD[1-1/(θCρComρR)]}v1(13)
T4＝α{1-ηD[1-1/(θCρComρR)]}T1(14)
and 5, point:
P5＝P1(15)
v5＝αRv1(16)
T5＝αRT1(17)
and 6, point:
P6＝P7+ΔP (18)
Figure BDA0001819787530000081
T6＝αsT7(20)
point 7 (post-turbo state point):
P7
v7
T7
in the formula, P11.010bar, P226.05bar, P3At 3.6bar, P41.084bar, P51.010bar, P7For the pressure, v, at the turbine outlet point 7 of the turbocharged rear compressor1The specific volume v of the flue gas at the state point 1 of the turbine outlet of the compressor2Specific volume, v, of flue gas at the state point 2 of the turbine outlet of the compressor3Specific volume, v, of flue gas at the outlet state point 3 of the compressor turbine4Specific volume v of flue gas at the state point 4 of the turbine outlet of the compressor5Specific volume, v, of flue gas at the state point 5 of the turbine outlet of the compressor7Specific volume of flue gas T at state point 7 of turbine outlet of compressor after turbocharging1For the compressor turbine outlet state point 1 temperature, T2For gas compressor turbineFlat outlet state point 2 temperature, T3At 3 point temperature, T, at the turbine outlet of the compressor4For the exhaust gas temperature, T, of the diesel engine5The discharge temperature of the waste heat boiler is set (generally, the discharge temperature of the waste heat boiler is set to be 180 ℃), T7The temperature of the compressor turbine outlet state point 7 after turbocharging.
And 4, step 4:
Figure BDA0001819787530000093
efficiency analysis
Because the system efficiency only considers the thermal efficiency of the system, the quality problem of energy is not involved, and the quality problem of the energy needs to be carried out on the system
Figure BDA0001819787530000094
The efficiency analysis is as follows:
fuel
Figure BDA0001819787530000095
The formula for E is:
Figure BDA0001819787530000091
wherein E is a fuel
Figure BDA0001819787530000096
，qmIs the mass flow of the flue gas, specifically 44098kg/h, CPIs the specific heat capacity of the flue gas at constant pressure, specifically CP＝1.004kJ/(kg.K)；
Output electric power
Figure BDA0001819787530000097
EP(kW) is calculated as:
EP＝qmCPηG[(T3-T2)-(T4-T1)](22)
in the formula, ηGη in this embodiment is generally given by the manufacturer for the efficiency of the generatorG＝0.97。
Heat output from the system
Figure BDA0001819787530000098
EQ(kW) is calculated as:
Figure BDA0001819787530000092
when the waste heat recovery of the main machine is increased and the waste heat boiler is not provided with a fan, the resistance of the waste heat recovery system is borne by the main machine, generally speaking, the exhaust gas temperature is increased by 7-10 ℃, the temperature is 10 ℃ at this time, and the wind resistance coefficient is αS＝1.016。
Efficiency E of turbocharging to diesel engineT(kW) is calculated as:
ET＝qmCPηT(T4-αST7) (24)
turbocharging efficiency η of the above formulaTGenerally speaking, 0.5 is removed, and for the convenience of calculation, in terms of the operation condition of a large number of turbocharged diesel engines, the exhaust temperature after turbocharging is basically kept stable, 340 ℃ is taken in the present case, so the formula 24 can be transformed into:
ET＝qmCPηT(α{1-ηD[1-1/(θCρComρR)]}T1-αST7) (25)
the equation 22 is modified to obtain:
Figure BDA0001819787530000101
system for controlling a power supply
Figure BDA0001819787530000105
The formula for calculating the efficiency epsilon is:
Figure BDA0001819787530000102
substituting the equations 23, 25 and 26 into the equation 27 to obtain the waste heat recovery system
Figure BDA0001819787530000106
Efficiency ε:
Figure BDA0001819787530000103
the temperature ratio parameter α is 6.06 calculated by equation 14, which corresponds to αRHas a value of 1.49 and a pressure ratio parameter thetaC2.53. The system can be calculated by substituting the calculated parameters into equation 28
Figure BDA0001819787530000107
The efficiency epsilon is 0.716, and the highest value of the system efficiency lies in the pressure ratio parameter thetaC＝3.1，
Figure BDA0001819787530000108
The efficiency epsilon is 0.726. As can be seen from equation 24, the equation is extremely complex and systematic
Figure BDA0001819787530000109
The efficiency is difficult to calculate directly from the parameters of the system, so the inventors have derived the system from equation 28
Figure BDA00018197875300001010
Efficiency epsilon and pressure ratio parameter thetaCOf a system
Figure BDA00018197875300001011
Efficiency epsilon is controlled by a pressure ratio parameter thetaCThe extreme value and the outlet temperature T of the compressor turbine of the diesel main engine control the compressor pressure P of the diesel main engine, so that the pressure ratio parameter theta in the waste heat recovery systemCTo a maximum, thereby indirectly maintaining the waste heat recovery system
Figure BDA00018197875300001012
The efficiency is the highest value, and the control of the state point during the recovery of the waste heat of the diesel engine is realized.
And 5: waste heat recovery system efficiency analysis
From the above equations, the various parameters of Table 3 can be found:
TABLE 3 Diesel host operating parameters
Figure BDA0001819787530000104
Taking the irreversible parameter ηD＝0.89，ηC＝0.88，ηG＝0.97，ρCom＝0.98，ρR＝0.98ηTWhen the exhaust temperature of the exhaust-heat boiler is 180 ℃, the exhaust-heat recovery system of a certain diesel engine can be calculated according to the formula 24 under the condition that the exhaust temperature is 0.5 DEG C
Figure BDA00018197875300001013
FIG. 2 shows the relationship between the efficiency and the pressure and temperature ratio parameters, where at α is constant, the relationship is shown as θCIs obviously increased to present a system
Figure BDA00018197875300001014
The extreme values of efficiency ε are shown in Table 4. therefore, when the diesel engine is operated under different loads, if necessary, the waste heat recovery can be calculated according to equation 27 in order to make the system
Figure BDA0001819787530000112
The efficiency epsilon is kept at the extreme point, thus ensuring that the operation of the system is at the highest point of efficiency, the pressure ratio parameters can be adjusted by calculation, table 4 is derived from fig. 2
Figure BDA0001819787530000113
The relationship between the efficiency extreme point and the pressure ratio parameter and the temperature ratio parameter.
TABLE 4
Figure BDA0001819787530000114
Relationship between efficiency extreme point and pressure ratio parameter and temperature ratio parameter
Figure BDA0001819787530000111
As can be seen from Table 4, when the load of the diesel engine for diesel power generation changes, the waste heat recovery system
Figure BDA0001819787530000115
The state point of extreme value appears in efficiency is constantly changing, so this application carries out numerical calculation to offshore oil platform's waste heat recovery process through the formula, adjusts pressure through the calculated result that obtains, guarantees that entire system's efficiency is at the highest value.
Step 6: keep highest system
Figure BDA0001819787530000116
Efficiency of
According to the waste heat recovery system obtained in step 5
Figure BDA0001819787530000117
The conversion relation between the efficiency epsilon and the pressure ratio parameter and the temperature ratio parameter is obtained to obtain a relation graph, and the relation graph is calculated by an automatic control system of a diesel engine when a waste heat recovery system is maintained
Figure BDA0001819787530000118
When the efficiency epsilon is the highest value, the pressure of the turbine outlet of the compressor state point 2' required by the diesel engine is obtained, the extreme value of epsilon calculated in the embodiment is 0.72, and the real-time temperature ratio parameter is 6.06 for example, so the pressure ratio parameter needs to be adjusted to 3.0, and then the pressure ratio parameter is adjusted to be the highest value
Figure BDA0001819787530000119
The system is at a maximum.
The system is designed for generating power by the diesel engine without considering the efficiency in waste heat recovery, the temperature of a state point 4 caused by resistance generally rises, if the system is required to be subjected to waste heat recovery, the pressure ratio parameter needs to be adjusted, according to the control method provided by the application, when the pressure ratio parameter of the diesel engine is unchanged, the temperature ratio required to be controlled for waste heat recovery is increased, and when the temperature ratio parameter is controlled to be 3.0, the efficiency of the system is 0.72, and the efficiency is improved by about 1.4%.
The foregoing is considered as illustrative of the preferred embodiments of the invention and is not to be construed as limiting the invention in any way. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims (8)

1. A draught fan-free waste heat recovery control method for a diesel engine of an offshore oil production platform is characterized by comprising the following steps:
step S1) determining a pressure ratio parameter theta of the diesel engine according to the inlet and outlet pressure, the inlet and outlet temperature and the flue gas specific heat ratio of the gas compressor of the diesel engineCAnd a windage coefficient αS；
Step S2) determining the efficiency η of the diesel engine according to the actual outlet temperature of the compressor of the diesel engine, the outlet temperature after irreversible loss and the environment temperatureCAnd expansion efficiency ηD；
Step S3) determining pressure holding coefficients rho of the combustion process and the heat recovery process of the diesel engine according to the outlet pressure of the compressor turbine of the diesel engine, the pressure after the combustion process of the combustion chamber and the specific heat ratio of the flue gas after combustionComAnd ρR；
Step S4) according to the parameter theta obtained in the steps S1-S3C、ηC、ηD、ρCom、αSAnd ρRDetermining working medium state point state parameters of outlets of a diesel engine;
step S5) determining the waste heat recovery system according to the parameters obtained in the steps S1-S4
Figure FDA0001819787520000012
An efficiency ε;
step S6) according to the waste heat recovery system of the diesel engine obtained in the step S5 under different loads
Figure FDA0001819787520000013
The extreme value of the efficiency epsilon determines the pressure ratio parameter theta of the diesel engineCBy the pressure ratio parameter thetaCThe temperature of the outlet of the compressor turbine of the diesel main engine controls the pressure of the compressor of the diesel main engine, thereby indirectly maintaining the waste heat recovery system
Figure FDA0001819787520000014
The efficiency epsilon is the highest value.
2. The offshore production platform diesel host fan-free waste heat recovery control method of claim 1, wherein step S5 is performed by the waste heat recovery system of formula 27
Figure FDA0001819787520000015
Efficiency ε:
Figure FDA0001819787520000011
in the formula, α is assumed to be the temperature ratio parameter of waste heat recovery and passes through T3＝αT1Obtained by ηGFor generator efficiency, ηTFor flue gas turbocharging efficiency, T1For flue gas temperature, T, at State Point 1 during waste Heat recovery3For flue gas temperature, T, at State Point 3 during waste Heat recovery5For flue gas temperature, T, at State Point 5 during waste Heat recovery7Is the flue gas temperature at state point 7 when the residual heat is recovered.
3. The offshore production platform diesel host fan-free waste heat recovery control method of claim 1, wherein the pressure ratio parameter θ of the diesel host is determined in step S1C：
θC＝T2′/T1＝(P2/P1)(γ-1)/γ(1)
Wherein gamma is the specific heat ratio of the flue gas, P1Pressure, P, for point 1 of diesel engine operating state2Pressure, T, for diesel engine operating state point 21For flue gas temperature, T, at State Point 1 during waste Heat recovery2’For state points 2' in the case of waste heat recoveryThe flue gas temperature and gamma are the specific heat ratio of the flue gas.
4. The offshore production platform diesel host fan-free waste heat recovery control method of claim 3, wherein the compressor efficiency η of the diesel host is determined in step S2CExpansion efficiency ηDThe following formula 2 and formula 3 show that:
ηC＝(T2′-T1)/(T2-T1) (2)
ηD＝(T3-T4)/(T3-T4′) (3)
in the formula, T1For the compressor turbine outlet state point 1 temperature, T2For the compressor turbine outlet state point 2 temperature, T2’For the compressor turbine outlet point 2' temperature, T3For compressor turbine outlet state point 3 temperature, T4For compressor turbine outlet state point 4 temperature, T4’The compressor turbine outlet condition point 4' temperature.
5. The offshore production platform diesel host fan-free waste heat recovery control method of claim 4, wherein the pressure holding coefficient p of the combustion process and the heat recovery process is determined in step S3ComAnd ρRThe following results from formulas 4 and 5:
ρCom＝(P3/P2)(γ-1)/γ(4)
ρR＝(P5/P4)(γ-1)/γ(5)
in the formula, ρComFor the pressure holding coefficient of the combustion process, pRPressure holding factor, P, for heat recovery processes2For the compressor turbine outlet state point 2 pressure, P3For compressor turbine outlet state point 3 pressure, P4For the compressor turbine outlet state point 4 pressure, P5The compressor turbine outlet state point 5 pressure.
6. The offshore production platform diesel host wind-free machine of claim 5The waste heat recovery control method is characterized in that the step S4 is a step S1-S3 according to the obtained parameter thetaC、ηC、ηD、ρCom、αSAnd ρRDetermining the combustion temperature T, the flue gas specific volume v and the pressure P of working medium state points at the outlets of turbines of the diesel main engine through the formulas 1 to 20, so that the system efficiency reaches the highest value;
point 1:
P1
v1
T1
and 2, point:
P2＝(θC)γ/(γ-1)P1(6)
v2＝[1+(θC-1)/ηC](θC)-γ/(γ-1)v1(7)
T2＝[1+(θC-1)/ηC]T1(8)
and 3, point:
P3＝(ρComθC)γ/(γ-1)P1(9)
v3＝α(ρComθC)-γ/(γ-1)v1(10)
T3＝αT1(11)
and 4, point:
P4＝(ρR)γ/(γ-1)P1(12)
v4＝α(ρR)-γ/(γ-1){1-ηD[1-1/(θCρComρR)]}v1(13)
T4＝α{1-ηD[1-1/(θCρComρR)]}T1(14)
and 5, point:
P5＝P1(15)
v5＝αRv1(16)
T5＝αRT1(17)
and 6, point:
P6＝P7+ΔP (18)
Figure FDA0001819787520000031
T6＝αsT7(20)
and 7, point:
P7
v7
T7
in the formula, P1-P7For pressures, v, at points 1-7 of the diesel engine operating state1-v7Specific volume of flue gas, T, at state points 1-71-T7The flue gas temperature at the state points 1-7 during waste heat recovery.
7. The offshore production platform diesel host fan-free waste heat recovery control method of claim 6, wherein step S5 is to determine fuel according to the parameter formulas 1-20, 21, 23, 25 and 26 obtained in steps S1-S4
Figure FDA0001819787520000035
E. Output electric power
Figure FDA0001819787520000036
EPHeat output by the system
Figure FDA0001819787520000037
EQAnd increased efficiency E of turbocharging to diesel engineT：
Figure FDA0001819787520000032
Figure FDA0001819787520000033
ET＝qmCPηT(α{1-ηD[1-1/(θCρComρR)]}T1-αST6) (25)
Figure FDA0001819787520000034
Wherein E is a fuel
Figure FDA0001819787520000041
qmIs the mass flow of flue gas, CPη is the constant pressure specific heat capacity of the flue gascomM is the irreversible loss of fuel upon combustionhFor fuel consumption, Qnetη for low calorific value of fuelGIs the efficiency of the generator.
8. The offshore production platform diesel host fan-free waste heat recovery control method of claim 1, wherein step S6 is based on the waste heat recovery system obtained in S5
Figure FDA0001819787520000042
The conversion relation between the efficiency epsilon and the pressure ratio parameter and the temperature ratio parameter is obtained to obtain a relation graph, and the automatic control system of the diesel engine is used for calculating and maintaining the waste heat recovery system
Figure FDA0001819787520000043
The pressure at the outlet of the compressor state point 2 required by the diesel engine when the efficiency epsilon is the highest value.
CN201811165683.0A 2018-09-30 2018-09-30 Fan-free waste heat recovery control method for diesel engine of offshore oil production platform Pending CN110966082A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811165683.0A CN110966082A (en) 2018-09-30 2018-09-30 Fan-free waste heat recovery control method for diesel engine of offshore oil production platform

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811165683.0A CN110966082A (en) 2018-09-30 2018-09-30 Fan-free waste heat recovery control method for diesel engine of offshore oil production platform

Publications (1)

Publication Number Publication Date
CN110966082A true CN110966082A (en) 2020-04-07

Family

ID=70028310

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811165683.0A Pending CN110966082A (en) 2018-09-30 2018-09-30 Fan-free waste heat recovery control method for diesel engine of offshore oil production platform

Country Status (1)

Country Link
CN (1) CN110966082A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3403595A1 (en) * 1984-02-02 1985-08-08 Hermann Dipl.-Ing. Dr.techn. 8061 Röhrmoos Hagen Engine heat loss recovery unit
US4685510A (en) * 1986-04-24 1987-08-11 American Gas Association Pulse combustion engine and heat transfer system
CN105787211A (en) * 2016-03-24 2016-07-20 华南理工大学 Pressure adjustment method for combined cycle heat recovery boiler with deteriorated gas turbine
CN107016187A (en) * 2017-03-31 2017-08-04 天津大学 A kind of optimization method for determining fume afterheat organic rankine cycle system parameter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3403595A1 (en) * 1984-02-02 1985-08-08 Hermann Dipl.-Ing. Dr.techn. 8061 Röhrmoos Hagen Engine heat loss recovery unit
US4685510A (en) * 1986-04-24 1987-08-11 American Gas Association Pulse combustion engine and heat transfer system
CN105787211A (en) * 2016-03-24 2016-07-20 华南理工大学 Pressure adjustment method for combined cycle heat recovery boiler with deteriorated gas turbine
CN107016187A (en) * 2017-03-31 2017-08-04 天津大学 A kind of optimization method for determining fume afterheat organic rankine cycle system parameter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
刘向龙: "海上采油设施主机余热回收过程的热力学研究", 《中国博士学位论文全文数据库工程科技Ⅱ辑》 *

Similar Documents

Publication Publication Date Title
US20140150447A1 (en) Load ramp and start-up system for combined cycle power plant and method of operation
CA1121606A (en) Installation for generating pressure gas or mechanical energy
Ibrahim et al. Effects of isentropic efficiency and enhancing strategies on gas turbine performance
EP3408506A1 (en) Combined cycle power plant
Saddiq et al. Modelling of gas turbine and gas turbine exhaust and its utilisation as combined cycle in utility system
CN110966115A (en) Waste heat recovery control method for diesel engine of offshore oil production platform
Reddy et al. Second law analysis of a natural gas‐fired gas turbine cogeneration system
CN110966082A (en) Fan-free waste heat recovery control method for diesel engine of offshore oil production platform
US20140013750A1 (en) Waste-heat recovery system
RU2369808C2 (en) Trigeneration gas turbine plant
CN110966083A (en) Turbocharging waste heat recovery control method for diesel engine of offshore oil production platform
Elwardany et al. Comparative evaluation for selected gas turbine cycles
RU2747704C1 (en) Cogeneration gas turbine power plant
RU2599082C1 (en) Gas turbine expander power plant of compressor station of main gas line
Zhang et al. Analysis of recuperated combined cycle with small temperature rise under design/off-design conditions
CN110805500A (en) Method for optimizing recovery efficiency of offshore oil production platform turbine main engine fan-free backheating circulation waste heat
CN110905684A (en) Method for optimizing regenerative cycle efficiency of offshore oil production platform turbine main engine
CN110878723A (en) Method for optimizing regenerative cycle and waste heat recovery efficiency of offshore oil production platform turbine main engine
Kaikko et al. Air bottoming cycle for cogeneration of power, heat and cooling
RU2767677C1 (en) Method of reducing the power of a gas turbine plant below its permissible lower limit of the control range
Fellah Effect of ambient temperature on the thermodynamic performance of a combined cycle
JP2000186568A (en) Gas turbine cogeneration device
RU2795147C1 (en) Combined-cycle plant with a semi-closed gas turbine plant
Cerza et al. Implementation of a Waste Heat Recovery Combined Cycle System Employing the Organic Rankine Cycle for a Gas Turbine
RU2743480C1 (en) Oxygen-fuel power plant

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20200407