Mini thermal generator sets
The electrical output of modern small capacity gas turbine and gas engine generator sets is about 20 kWe–20 MWe. These generator sets are widely used in industry, housing and utilities infrastructure, trade and sports complexes, and also to provide oil and gas fields with heat and electric power.
The mini-thermal generator set is an individual power system – a power unit for combined power and heat generation to meet the requirements of each individual consumer. As a rule, the mini- thermal generator set uses gas turbines and gas engines of small capacity (up to 20 MWe). Heat recovery steam generators utilize exhaust heat and produce heat for domestic and industrial purposes (on site heating, hot water supply, steam). Combined power and heat generation is called cogeneration. The operating efficiency of mini-thermal generator sets depends on selecting the right equipment and implementing proper operating modes.
The advantages of using gas-turbine generator sets are as follows: low emissions (9-25 ppm), high efficiency (31-39%), reliability, flexibility. When using the cogeneration cycle, the thermal efficiency of a gas turbine generator set increases up to 85%. The vibration and noise level of gas-turbine generator sets is about 65-85 db. which is tolerable and therefore it can be installed in proximity to the energy consumers. Also, the modular configuration of a gas turbine generating set (making it easy to assemble) means a considerable reduction the start-up time.
The electrical efficiency of gas engine generator sets is quite high and can reach 41-43% when utilizing Russian natural gas. The exhaust-gas temperature of a gas-turbine generator set is ~ 390 ± 10°С which is suitable for the cogeneration cycle. However it should be noted that these sets have quite high operating and service costs.
The choice between a gas turbine generator set and a gas engine generator set revolves around the fact that turbines have a higher unit power than piston engines but are less efficient, especially in case of partial load operation
The main advantages of mini- thermal generator set is that it offers:
- A flexible scheme which supplies the consumer with electric power and heat
- Unbroken power supply to the plant
- Cheaper power and heat
- High quality power delivered to the consumer;
- High efficiency and minimum losses in transmission lines;
- Regular power supply to consumers in remote regions.
There are several advantages to installing a mini thermal generator set (as opposed to a large thermal power station) near to the consumer.
- No need to construct expensive and dangerous high-voltage power lines (PL)
- No power loss in transmission lines
- No need to connect to the commercial power supply, thus making a big cost saving
- Unbroken power supply to the consumer
- Stable supply of high-quality power, which has voltages and frequency values within standard limits
The mini thermal generator set, operating in cogeneration mode, utilizes a significant part of the produced energy as thermal energy. Below are variations of this utilized heat:
- Thermal energy directly available for end users (cogeneration)
- Hot water supply (HWS), heating, process steam
- Partial transformation of heat into cooling energy (trigeneration);
- Cold is generated by an adsorption refrigerator which consumes not electric power but heat; this can supply air conditioning in summer or for other consumption such as deep freezing.
Another variant of the gas turbine generation set is the modular configuration system (cluster). The modular mini power facility consists of several identical gas turbine generator sets controlled by an integrated control system. This allows increasing power output (load) at short notice and at low cost.
The automated control systems in the gas - turbine power plant eliminate the need for human presence. Monitoring of gas-turbine generator sets can be carried out through various long distance telecommunications. Complex protection systems are provided in case of emergencies.
Gas-turbine generator sets are highly reliable. We have factory data monitoring non-stop performance over a period of 5-7 years. Suppliers of modern gas turbines are able to overhaul spare parts without transporting them back to the manufacturer which greatly reduces overall costs. Another advantage of the gas - turbine generator set is its long economic life, in the region of 150,000 hours, and an overhaul period of 30,000-60,000 hours). Some brands of gas-turbine generator sets operate reliably with various kinds of fuel gas, including associated gas with a 5 % hydrogen sulphide content, and with no special treatment.
The following manufacturers and suppliers of gas-turbine generator sets are currently operating in the Russian market:
Capstone, General Electric, Caterpillar, Kawasaki, MAN TURBO AG, Mitsubishi Heavy Industries, OPRA, Rolls-Royce, Siemens, Solar Turbines, Turbomach, Ingersoll Rand, etc.
