1、 Overview of ORC Low Temperature Waste Heat Power Generation ORC low-temperature waste heat power generation is an efficient and energy-saving technology, which mainly generates electricity by recovering low-grade heat contained in medium and low-temperature waste gas, steam, hot water, etc. emitted from the production processes of industries such as steel, cement, and petrochemicals, turning waste into treasure. One important reason for the low energy utilization rate in China is the underutilization of low-temperature waste heat energy. ORC low-temperature waste heat power generation can help improve energy utilization efficiency. The low-temperature heat source here refers to heat sources with temperatures below 250 ℃ but above 80 ℃, including industrial process waste heat, solar energy, ocean temperature difference, geothermal energy, etc. In the industrial field, low-temperature waste heat generally refers to the residual heat, condensed water, and hot water generated during industrial production processes below 200 ℃; Gas below 150 ℃ and heat generated by exhaust gases from boilers and industrial heating furnaces. 2、 ORC power generation principle and process （1） Principle Organic Rankine Cycle (ORC) is a Rankine cycle that uses low boiling point organic compounds as working fluids. Organic working fluids can vaporize at lower temperatures to generate higher pressure, which drives turbines (turbines) to do work. For example, organic working fluids represented by R245fa (boiling point at 15.3 ℃ under normal pressure) can achieve effective power generation at lower temperatures compared to water (boiling point at 100 ℃ under normal pressure). They can recover low-grade waste heat for power generation below 250 ℃, convert low-grade waste heat resources into high-quality electricity, facilitate long-distance energy transmission and secondary utilization, and reduce traditional energy consumption and greenhouse gas emissions. （2） Process Heat source circuit (red pipeline) The heat source (waste heat resource) flows through the red pipeline and enters the evaporator of the unit, transferring heat to the working fluid inside the unit. The temperature of the heat source water decreases and leaves the evaporator, and is sent to the subsequent process 1. Organic working fluid circuit (green pipeline) Liquid working fluid enters the evaporator, absorbs heat from the heat source, becomes saturated or superheated steam, enters the turbine turbine, converts thermal energy into mechanical energy, and drives the generator to output electricity externally. The superheated steam refrigerant then enters the condenser and is cooled by cooling water to become a liquid, which then enters the refrigerant pump. The working fluid pump drives the working fluid to flow repeatedly. The cooling water is driven by a water pump and enters the condenser of the unit to cool the working fluid. The temperature of the cooling water rises and leaves the condenser, and is sent to the cooling tower to dissipate heat to the atmospheric environment. Power grid (yellow part) The generator generates electrical energy and connects it to the power grid for use. 3、 Equipment configuration of ORC generator set The low-temperature waste heat power generation system mainly includes the following main equipment: ORC generator set, vertical centrifugal turbine generator, centripetal turbine, control system, condensate tank, condensate pump, cooling tower system, etc. 4、 Characteristics of ORC generator set Equipment structure and installation aspects The equipment is designed with a modular structure, making transportation and installation easy. In terms of operational performance Easy to operate, with strong load fluctuation ability, capable of stable operation within the range of 40% -110%. Equipment material and mass transfer aspects Adopting efficient and structurally sound mass transfer equipment and reliable materials. Control and grid connection aspects PLC can be used for automatic control of the device, and key parameters are automatically regulated by PLC; The generator can automatically track grid parameters and connect to the grid automatically. The power generation device intelligently monitors the status of the power grid, providing stable electrical energy without any impact on the grid. In terms of safety performance Safe and reliable, equipped with a pressure relief system, over temperature alarm system, and advanced self-control system. In terms of working fluid and turbine generator design Adopting environmentally friendly working fluid R245fa, the integrated design of turbine and generator ensures no leakage. Cooling system aspect The unit has advanced equipment self cooling system, without the need for external oil separation and cooling system. 5、 Types and characteristics of ultra-low temperature waste heat generators Ultra low temperature waste heat generators are mainly divided into the following types according to the different technical routes of expansion machines: Screw expander It is a relatively mature expansion machine technology in China, with low technical content. The isentropic expansion efficiency of its expansion work is generally around 70%. Using traditional mechanical bearings and traditional generators, the system's power generation efficiency is relatively low. Gear speed increasing high-speed turbine expander By using high-speed turbines, high entropy expansion efficiency is achieved, but with the use of gearbox speed increase and mechanical bearings, mechanical wear is severe and maintenance costs are high in the later stage. At the same time, both of the above technical routes have the problem of dynamic sealing technology between rotating components and shells, making it difficult to achieve zero leakage of organic working fluid. Magnetic levitation high-speed turbine expander 6、 Working fluid pump in ORC low-temperature waste heat power generation system The working fluid pump is a basic component of the ORC low-temperature waste heat power generation system. It is a device that delivers the low-temperature and low-pressure liquid organic working fluid from the condenser to the inlet of the evaporator under high pressure after adiabatic pressurization. There are various types of working fluid pumps suitable for ORC low-temperature waste heat power generation systems on the market, such as hydraulic diaphragm pumps, which have the characteristics of high pressure, suitability for hazardous chemical media, and simple maintenance; The vertical centrifugal pump adopts variable frequency speed regulation and mechanical sealing; Multi stage centrifugal pumps can achieve higher head and set pressure. Multi stage centrifugal pumps are two or more centrifugal pumps with the same function installed in the centrifugal pump stage, which can deliver more flow compared to reciprocating pumps such as piston pumps.