Generation efficiency of gas-fired generating units usually ranges from 30% to 40%, and the more common types can reach 35%. The most prominent advantages of gas internal combustion engine are high power generation efficiency, followed by high integration of equipment, fast installation, low dust appeal in gas, little water demand, and low unit kilowatt cost of equipment. But the internal combustion engine also has some deficiencies. Firstly, when the internal combustion engine extinguishes the low calorific value fuel, the output of the unit obviously drops. When a 500 kW gas-fired internal combustion generator unit extinguishes the low calorific value 8000 kcal/cubic meter natural gas fuel, the output may drop to about 350-400 kW when using the low calorific value 4000 kcal/cubic meter coking gas.
In addition, the internal combustion engine needs to change oil and spark plug frequently, which consumes a lot of materials. It also affects the usability and reliability of the two main equipment application indicators. It has a greater impact on the equipment application rate. Sometimes, it has to adopt the method of increasing the number of generating units to eliminate the impact of low application rate. Internal combustion engine equipment is sensitive to water molecule content and hydrogen sulfide in coking gas, which may cause hydrogen sulfide and water to form sulfuric acid corrosion problem. Some necessary measures should be taken to suppress it.
Gas turbines are more suitable for inferior fuels with high hydrogen content, low calorific value and more impurities in gases. Some gas turbines use crude oil and high sulfur residue fuels. The generation efficiency of gas turbine itself is not very high, usually between 30% and 35%, but the temperature of waste heat flue gas is as high as 450-550 C. It can be recycled by waste heat boiler to convert steam, drive steam turbine to generate electricity again, and form gas turbine-steam turbine separated cycle power generation. The generation efficiency can reach 45%-50%. Some large-scale units can exceed 55%. 。
The advantages of using gas turbines are relatively more, firstly, the availability and reliability of the equipment are relatively high, and the comprehensive application rate can generally be maintained at 90%; secondly, the fuel compliance is relatively strong, and the problems of high sulfur and dust content are not serious; thirdly, the power output of power generation is generally not reduced, so that the fuel intake increases; moreover, the power density of gas turbines is high. The coking gas application of some uncertain coking plant projects is very favorable.
However, there are advantages and disadvantages in the affairs of the world. There are no perfect things. The higher the intake pressure of gas turbine is, the higher the intake pressure of fuel of the unit with high power generation efficiency is. Because there is no pressure in the coking gas itself, it is necessary to use the gas compressor to tighten the gas demand and consume a lot of energy, which affects the theoretical output power of the equipment. Some projects result in the consumption of 15%~20% of the power of the gas turbine. The project of separation cycle arrives at the film. The noise may be 10%~15% of the output power; the separate circulation system has the same water resource conditions as the steam turbine, which makes the system more complex, the investment is larger, and the relocation is more difficult.
There are some precautions for operating natural gas generating units. When we use it, we often neglect the pre-operation inspection because we are familiar with the operation process. It is necessary to check the natural gas generating units before they are actually operated. Especially in early spring. Due to the gradual warming of the weather, the change of outdoor environment makes the demand of natural gas generating units have a process of adaptation. Moreover, due to the relatively large winter monsoon, parts and components are prone to aging, and all aging parts and components should be discontinued and replaced. Detailed inspection items have the following points:
1. Carefully inspect the natural gas generating units to ensure that there is no "three leakage" problem, that is, oil leakage, water leakage, air leakage and other phenomena. Guarantee the solidity of the wire connection.
2. To ensure the lubricating oil level of natural gas generating units, assuming that there is a lack of lubricating oil, the same brand and the same quality of lubricating oil should be used to make up for it.
3. The voltage of natural gas generator set should be between 24-27V.
4. Check the level of coolant to ensure adequate coolant.
5. The emergency stop switch should be turned on in order to automatically pop up at the time of the accident. Guarantee the defect maintenance of natural gas generator set.
This article is written by biogas generating units. For more products and more details, please pay attention to our official website http://www.huannengpower.com.