CN212563454U

CN212563454U - Biomass biogas and organic Rankine cycle combined power generation system

Info

Publication number: CN212563454U
Application number: CN202021548405.6U
Authority: CN
Inventors: 张成军; 曹烜军
Original assignee: Beijing Lhl Holding Group Co ltd
Current assignee: Beijing Lhl Holding Group Co ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2021-02-19
Anticipated expiration: 2030-07-30

Abstract

The utility model discloses biomass marsh gas and organic rankine cycle combined power generation system contains biomass marsh gas power generation system and organic rankine cycle power generation system, and biomass marsh gas power generation system contains biogas fermentation system, and biogas generating set connects the high temperature flue gas pipeline, and biogas fermentation system connects low temperature process water pipeline and high temperature process water pipeline; the organic Rankine cycle power generation system comprises an evaporator, wherein the evaporator is connected with a low-temperature heat conduction oil pipeline and a high-temperature heat conduction oil pipeline; the high-temperature flue gas pipeline is connected with a waste heat boiler, the waste heat boiler comprises a main flue and a bypass flue, the main flue and the bypass flue are connected with the high-temperature flue gas pipeline, a heat conduction oil heater is arranged in the main flue, and the heat conduction oil heater is connected with a low-temperature heat conduction oil pipeline and a high-temperature heat conduction oil pipeline; the bypass flue is connected with a process water heater, and the process water heater is connected with a low-temperature process water pipeline and a high-temperature process water pipeline. The utility model discloses carry out better utilization to conventional living beings biogas power generation system's flue gas waste heat.

Description

Biomass biogas and organic Rankine cycle combined power generation system

Technical Field

The utility model relates to a power generation system, especially a combined power generation system who combines current living beings marsh gas power generation system and organic rankine cycle power generation system.

Background

Biomass biogas power generation systems and Organic Rankine Cycle (ORC) power generation systems are power generation systems that have achieved commercial operation.

The biomass methane power generation technology mainly comprises two parts of methane fermentation and power generation.

The definition of biogas fermentation is: biogas fermentation, also known as anaerobic fermentation or anaerobic digestion, refers to a process of finally producing biogas by the catabolism of various microorganisms with various types, large quantities and different functions under anaerobic conditions with organic substances (such as crop straws, weeds, human and animal excreta, garbage, sludge, municipal sewage, industrial organic wastewater and the like).

The methane combustion power generation is a methane utilization technology which appears along with the continuous development of large-scale methane tank construction and methane comprehensive utilization, and the methane generated by anaerobic fermentation treatment is used on an engine and is provided with a comprehensive power generation device to generate electric energy and heat energy. The biogas power generation has the characteristics of efficiency creation, energy conservation, safety, environmental protection and the like, and is a distributed energy source with wide distribution and low price.

Biogas power generation has been widely regarded and actively promoted in developed countries. Biomass energy power generation grid connection accounts for about 10% of the total energy in some countries in western europe.

The methane power generation technology is a new energy comprehensive utilization technology integrating environmental protection and energy conservation. The method utilizes a large amount of organic wastes (such as vinasse liquid, livestock and poultry manure, municipal refuse, sewage and the like) in industry, agriculture or urban life to generate biogas through anaerobic fermentation treatment, drives a biogas generator set to generate electricity, and can fully use the waste heat of the generator set for biogas production.

The heat efficiency of the biogas power generation cogeneration project is greatly different according to different power generation equipment, if a gas internal combustion engine is used, the heat efficiency is 70-75%, and if a gas turbine and a waste heat boiler are used, the heat efficiency can reach more than 90% under the condition of afterburning.

The biogas power generation technology provides clean energy, not only solves the environmental problem in biogas engineering, consumes a large amount of waste, protects the environment and reduces the emission of greenhouse gases, but also changes waste into valuable, generates a large amount of heat energy and electric energy, accords with the environmental protection idea of energy recycling, and brings great economic benefit.

An organic Rankine cycle system (ORC) adopts organic working media to replace vapor of Rankine cycle as the working media, and is widely applied to the fields of biomass power generation, industrial waste heat utilization, geothermal utilization and the like. The organic Rankine cycle power generation technology has the following advantages: the initial investment cost is low; the operation and maintenance cost is low; the working temperature of the circulating medium is low, and the safety is relatively high; the system is generally of an integral prying block type structure, and construction and installation are facilitated. Compared with biomass biogas power generation, in a system with the unit capacity of 0.1-10 MW, the organic Rankine cycle waste heat power generation technology is adopted, so that the cascade utilization of energy is realized, and the method is safe and has the best economic benefit.

In the conventional biomass biogas power generation project, because the temperature of the flue gas of the biogas after the internal combustion engine does work and generates power is still very high, the direct discharge of the biogas inevitably causes energy waste.

In order to recover the part of heat, a waste heat boiler is generally arranged behind the methane internal combustion engine, and the temperature of the flue gas is reduced by a heat exchanger in the waste heat boiler and then is discharged to the atmosphere. When the waste heat boiler adopts a flue gas heat exchanger for heat exchange, water working medium is usually heated into hot water or steam, and then the hot water or steam is sent to a heat user through a pipeline. Because the heated steam has low parameters and low thermoelectric conversion efficiency, the method can not be generally applied to a Rankine cycle steam turbine power generation system adopting steam and water as working media.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problem that a biomass marsh gas and organic rankine cycle combined power generation system is provided, carry out better utilization to conventional biomass marsh gas power generation system's flue gas waste heat.

The utility model discloses the technical means who adopts is: a biomass methane and organic Rankine cycle combined power generation system comprises a biomass methane power generation system and an organic Rankine cycle power generation system, wherein the biomass methane power generation system comprises a methane fermentation system, the methane fermentation system is connected with a methane generator set, the methane generator set is connected with a high-temperature flue gas pipeline, and the methane fermentation system is connected with a low-temperature process water pipeline and a high-temperature process water pipeline; the organic Rankine cycle power generation system comprises an evaporator, wherein the evaporator is connected with a low-temperature heat conduction oil pipeline and a high-temperature heat conduction oil pipeline; the high-temperature flue gas pipeline is connected with a waste heat boiler, the waste heat boiler comprises a main flue and a bypass flue, the main flue and the bypass flue are connected with the high-temperature flue gas pipeline, a heat conduction oil heater is arranged in the main flue, and the heat conduction oil heater is connected with a low-temperature heat conduction oil pipeline and a high-temperature heat conduction oil pipeline; the bypass flue is connected with a process water heater, and the process water heater is connected with a low-temperature process water pipeline and a high-temperature process water pipeline.

And a bypass baffle gate is arranged at the inlet of the bypass flue.

The top of the waste heat boiler is provided with a low-temperature flue gas pipeline, a main flue of the waste heat boiler is merged into the low-temperature flue gas pipeline after passing through the heat transfer oil heater, and a bypass flue of the waste heat boiler is merged into the low-temperature flue gas pipeline after passing through the process water heater.

The utility model discloses the beneficial effect who reaches as follows: the organic Rankine cycle power generation technology adopts a special organic working medium, and under the same design pressure, the phase change evaporation temperature is lower than that of water working medium, namely the required latent heat of vaporization is lower than that of the water working medium, the required temperature for a heat source is generally between 90 ℃ and 350 ℃, and is far lower than the requirement of a steam-water working medium Rankine cycle power generation system on the temperature of a boiler hearth. The ORC unit generally adopts a modular design, and has short construction and installation periods and convenient maintenance. After the organic Rankine cycle power generation technology and the biomass methane power generation technology are combined, the high-temperature flue gas heat in the biomass methane power generation system is fully utilized and converted into electric energy, so that the principle of energy cascade utilization is met, and more economic benefits are created for enterprises.

Drawings

Fig. 1 is a schematic diagram of the system structure of the present invention.

Detailed Description

As shown in fig. 1, the biomass methane and organic rankine cycle combined power generation system of the present invention includes a biomass methane power generation system 1 and an organic rankine cycle power generation system 13, both of which are existing mature systems.

As shown in the figure, the biomass biogas power generation system 1 includes a biogas fermentation system 20, the biogas fermentation system 20 is connected to a biogas power generation unit 21, a part of biogas generated by the biogas fermentation system 20 in the biogas power generation system 1 and purified is transmitted to a biogas output end 23 through a pressure boosting system 22, for example, the biogas can be transmitted to a gas storage cabinet or a biogas user, the other part is transmitted to the biogas power generation unit 21 to do work to generate power, and the power is transmitted to a power output end 24 through a power grid line. The biogas generator set 21 is connected with the high-temperature flue gas pipeline 2, and the biogas fermentation system 20 is also connected with the low-temperature process water pipeline 9 and the high-temperature process water pipeline 10.

The organic rankine cycle power generation system 13 includes an evaporator 31, and the evaporator 31 is connected to the low-temperature thermal conductive oil pipe 11 and the high-temperature thermal conductive oil pipe 12. The evaporator 31 is further connected to other devices such as a steam turbine and a generator, and the devices and the connecting devices in these figures are all structures of the conventional organic rankine cycle power generation system, and are not described herein again.

The high-temperature flue gas pipeline 2 is connected with a waste heat boiler 30, and the top of the waste heat boiler 30 is provided with a low-temperature flue gas pipeline 8. The waste heat boiler comprises a main flue 3 and a bypass flue 5, the main flue 3 and the bypass flue 5 are connected with a high-temperature flue gas pipeline 2, a heat conduction oil heater 4 is arranged in the main flue 3, and the heat conduction oil heater 4 is connected with a low-temperature heat conduction oil pipeline 11 and a high-temperature heat conduction oil pipeline 12; the inlet of the bypass flue 5 can be provided with a bypass baffle gate 6 and is connected with a process water heater 7, and the process water heater 7 is connected with a low-temperature process water pipeline 9 and a high-temperature process water pipeline 10.

The temperature of the flue gas generated after the methane generates electricity and does work in the internal combustion engine is about 500 ℃, and one part of the flue gas passes through the main flue 3 of the waste heat boiler, is sent to the low-temperature flue gas pipeline 8 after heat is recovered by the heat conduction oil heater 4, and is finally discharged into the atmosphere through a chimney; the other part of the flue gas passes through a bypass flue 5 of the waste heat boiler, is merged into a low-temperature flue gas pipeline 8 after heat is recovered by a process water heater 7, and is finally discharged into the atmosphere by a chimney. Low-temperature heat conduction oil from an evaporator in the organic Rankine cycle power generation system 13 is sent to the heat conduction oil heater 4 through the low-temperature heat conduction oil pipeline 11, changed into high-temperature heat conduction oil after absorbing heat and sent back to the evaporator for heat exchange through the high-temperature heat conduction oil pipeline. The low-temperature process water in the biogas power generation system 1 is sent to the process water heater 7 through the low-temperature process water pipeline 9, changed into high-temperature process water after absorbing heat and sent back to the biogas fermentation system through the high-temperature process water pipeline 10.

And a bypass baffle valve 6 is arranged at the inlet of the bypass flue 5 of the waste heat boiler and can be used for controlling the amount of flue gas entering the bypass flue. Because the methane fermentation process is greatly influenced by the environmental temperature, the reaction temperature of the fermentation system needs to be maintained in order to ensure the stable methane yield, and an external heating source needs to be introduced. Because the environment temperature in summer is higher, the heat required by the biogas fermentation system is less, the opening degree of the bypass baffle 6 is reduced when the working condition is operated, most of the rest flue gas flows through the main flue 3 of the waste heat boiler, and the power generation power of the organic Rankine cycle power generation system 13 is higher; and the environmental temperature is lower in winter, the heat required by the biogas fermentation system is more, the opening degree of the bypass baffle 6 is increased when the working condition is operated, the rest of the flue gas flows through the main flue 3 of the waste heat boiler, and the power generation power of the organic Rankine cycle power generation system 13 is lower at the moment.

Claims

1. A biomass methane and organic Rankine cycle combined power generation system comprises a biomass methane power generation system and an organic Rankine cycle power generation system, and is characterized in that the biomass methane power generation system comprises a methane fermentation system, the methane fermentation system is connected with a methane generator set, the methane generator set is connected with a high-temperature flue gas pipeline, and the methane fermentation system is connected with a low-temperature process water pipeline and a high-temperature process water pipeline;

the organic Rankine cycle power generation system comprises an evaporator, wherein the evaporator is connected with a low-temperature heat conduction oil pipeline and a high-temperature heat conduction oil pipeline;

the high-temperature flue gas pipeline is connected with a waste heat boiler, the waste heat boiler comprises a main flue and a bypass flue, the main flue and the bypass flue are connected with the high-temperature flue gas pipeline, a heat conduction oil heater is arranged in the main flue, and the heat conduction oil heater is connected with a low-temperature heat conduction oil pipeline and a high-temperature heat conduction oil pipeline; the bypass flue is connected with a process water heater, and the process water heater is connected with a low-temperature process water pipeline and a high-temperature process water pipeline.

2. The biomass biogas and orc combined power generation system of claim 1, wherein the bypass flue inlet is provided with a bypass damper gate.

3. The biomass biogas and organic Rankine cycle combined power generation system according to claim 1, wherein a low-temperature flue gas pipeline is arranged at the top of the waste heat boiler, a main flue of the waste heat boiler passes through the heat transfer oil heater and then is merged into the low-temperature flue gas pipeline, and a bypass flue of the waste heat boiler passes through the process water heater and then is merged into the low-temperature flue gas pipeline.