การประยุกต์ใช้งานโมเดลขอบเขตการเคลื่อนที่ในการจำลองแบบไดนามิกของ ระบบฟาร์มปศุสัตว์แบบอินทรีย์ออร์ค (Orc Rkine Cycle - Orc ) ที่ขับเคลื่อนโดยทีมโครงการไอเสีย

Moving Boundary Model Application in the Dynamic Simulation of an Organic Rankine Cycle ( ORC) System Driven by Exhaust Project team   


What is ORC low-temperature waste heat power generation technology;

Low-temperature waste heat power generation technology refers to the technology that converts low-temperature waste heat into electrical or mechanical energy to improve the flexibility of energy utilization. Low temperature waste heat power generation system includes water (steam) cycle power generation system, organic working medium cycle power generation system, external combustion engine hot gas engine cycle power generation system, supercritical carbon dioxide cycle power generation system, etc. At present, the ORC (Organic Rankine Cycle) technology is representative in this field after decades of development.

The organic Rankine cycle power generation system is a Rankine cycle with low boiling point organics as the working medium. It is mainly composed of waste heat boiler (or heat exchanger), turbine (a machine that converts the energy contained in the fluid medium into mechanical work), condenser and working medium pump. The organic working medium absorbs heat from the residual heat flow in the heat exchanger to generate steam with a certain pressure and temperature. The steam enters the turbine machinery to expand and work, thus driving the generator or dragging other power machinery. The steam discharged from the turbine releases heat to the cooling water in the condenser, condenses into liquid, and finally returns to the heat exchanger with the help of the working medium pump, so as to continue to circulate.

The ORC system has three major technical advantages:

1. It is a high-speed turbine expansion turbine direct-driven permanent magnet power generation technology, with the power generation efficiency of 84%, and has the characteristics of high speed, compact structure, and better adaptability to different working conditions and occasions;
2. It is the technology of low temperature heat transfer efficiency and high heat exchanger. By studying the optimal evaporation pressure under different working parameters (including the inlet temperature of the heat source, the mass ratio of the heat source fluid and the working fluid) and the maximum heat recovery efficiency technology, the maximum point of the total efficiency of the heat recovery system under the optimal working fluid flow is determined;
3. It is the integrated design technology of high-speed permanent magnet generator and converter. The PWM rectifier control algorithm is introduced into the motor design to achieve the optimal design of generator parameters. The AC-DC-AC frequency conversion system based on dual PWM converter is adopted, and the grid connection technology of full power converter is applied to improve the power generation efficiency of the system. Through the reasonable control of the converter, the optimal capture power speed is achieved, The low-temperature waste heat direct-driven generator uses full-power converter to isolate the power grid from the generator, which has high reliability and stability.

ORC low temperature waste heat power generation technology application direction;

ORC low temperature waste heat power generation system can be widely used in steel, cement, petrochemical, electric power, metallurgy, glass and other industries, to reduce energy consumption, environmental protection is of great significance. The low-grade energy (energy with low conversion efficiency) available in ORC low-temperature waste heat power generation system is mainly in the following forms:

1. Industrial waste heat. Recycling industrial waste heat can reduce industrial energy consumption and greenhouse gas emissions. Most industrial processes or power plant emissions can be used, the temperature is generally not higher than 400ºC.

2. Geothermal heat. Geothermal power generation uses geothermal steam or hot water as a heat source. All the geothermal fields discovered in our country are hot water heat storage. Most of the geothermal water used is near saturation, and the temperature is generally not more than 200ºC.

3. Solar energy. Solar energy density is low, heat source temperature is not high, need to use the organic Rankine cycle thermoelectric system based on heat collection technology, after the heat collection device, the temperature can reach 300ºC. For example, a plate collector is used to collect solar hot water below 100ºC as a driving heat source, and ORC permeability is used to form a low temperature solar thermal power generation system, which can be used as a distributed energy.

4. Biomass energy. Biomass energy is also one of the important driving sources of organic Rankine cycle. Organic Rankine cycle is adopted for biomass power generation mainly because organic working medium has higher turbine efficiency when unit size is small. In addition, the organic Rankine cycle is also used for cold energy recovery of liquefied natural gas (LNG).