Advantages of Gas Engines

1. Fuel Flexibility. The biggest advantage is that gas engines can burn natural gas and a variety of other gases. The limited availability of many of the organic and process gases necessitates the use of natural gas as a standby source. Switching from one source is rather easy in the gas engine. They can burn low calorific value gases, low methane number gases, and gases that have fluctuating fuel composition like landfill gas.

2. Fuel Pressures. Gas pressure requirement of a gas turbine is high often in the range of 17 to 20 bar. If the supply gas pressure is low, this requires the addition of a gas pump that increases investment and operation costs. Supply of gas from biomass or other organic sources are at low pressures. Gas engines operate with low inlet gas pressures in the range of 200 mbar.

3. Speed. As an internal combustion engine, gas engines run at much lower speed, 750 or 1500 rpm against the 14000 RPM for smaller gas turbines. There is no need of a gear box. This is much less stress on the rotating elements, combustion path, and bearings, making gas engines cheaper. This also results in a much higher Mean Time Between Outages.

4. Ambient Effect. Gas turbine output reduces with the increase in ambient temperature. Gas engine output reduces only when the ambient temperature reduces the effectiveness of the cooling system.

5. Startup. Gas turbines require high power to start-up, to bring the rotor to synchronous speed. This requires a backup power or stand by DG set, or compressed air pressure or gas pressure. Gas engines can crank start from battery power.

6. Efficiency. In the lower power range, gas turbine efficiencies are in the range of 28 % in the open cycle mode. Present day large capacity gas engines provide greater than 40 % efficiency.

7. Exhaust Temperature. Gas turbine exhaust temperature is in the order of 450 °C. Unless there are exhaust heat recovery devices, the exhaust stack and ducts design should be for these high temperatures. This will also require a higher stack to avoid heat dissipation problems. Gas engines in the stand-alone mode have much lower gas temperatures in the range of 150 °C.

8. Emissions. The lower combustion temperature and lean air burning produces less NOx.

9. Maintenance. Skills required for maintenance follow the well-developed IC engine lines and is thus available in almost all parts of the world. Gas engines are very reliable and run for almost 100 % availability resulting in low costs. Gas turbines require high technology and more time for maintenance.

10. Cost. All of the above makes gas engine a lot cheaper, with lower capital costs and lower O& M costs.

For low output power generation with environmentally friendly fuel gases, gas engines are a better option than gas turbines.

https: //www.brighthubengineering.com/power-plants/108429-reciprocating-gas-engines-for-biomass-powerplants/

FERC Security Program for Small Hydropower Projects

Energy & Power Plants / By Baby Rani / Mechanical Engineering

Introduction

Hydropower in any country is regulated both during the construction and operational stages. Since the safety of hydropower and dams is a significant part of FERC’s mandate, safety gets a top priority. Prior to construction, the commission staff inspects and sanctions programs and stipulations for the project. Staff engineers are responsible for both examining the project and then for inspecting it on a regular basis.

Prompt approval for any type of energy scheme is uncommon. This is true in the case of small hydropower, too. (Some cases have required more than fifteen years for approval.) This has been a major restraint in the growth of significant private energy substructure in the U.S.

Nevertheless a novel, reassuring movement is arising in the hydropower industry. Recognizing the requirement for clean, inexhaustible energy, FERC is implementing plans to hasten the licensing procedure for small hydropower projects.

⇐ Предыдущая12345678Следующая ⇒

Поделиться: