Chinese Industrial Gas Turbine Engines

The conversion of aeroengines into the industrial and marine gas turbine engines is an important business. The turbomachine which turns the energy of high temperature and high pressure gas flow into mechanical energy is generally called a gas turbine engine. Apart from its use as an aircraft power plant, the gas turbine engine is also widely used in industry and ships. Compared with conventional internal combustion engines and steam engines, the gas turbine has a much higher operating temperature. In its industrial application, the high temperature and high pressure gas expands and produces useful work through the turbine, which in turn drives the generator. The exhaust gas is still about 500 degrees C and it could go to the residual heat boiler, which in turn produces high pressure steam. The steam drives the steam turbine for electricity generation for the second time (the steam and the hot water can also be used directly). The waste gas from the boiler can be absorbed by the heat exchanger for the industry and daily uses. The heat energy of the fuel can be exploited in steps and the combined heat utilization rate will reach more than 80%.

The gas turbine has the following advantages: light weight, small size, quick start, high reliability, no need for cooling water and adaptable to various fuels such as diesel, heavy oil, petroleum, natural gas, tail gas, low heat value gas, etc. It is easy to install or dismount, with a small amount of construction work, and can be remotely auto-controlled. Therefore, the gas turbine engine is a more adaptable, advanced, energy saving power plant. The industrial countries in the world all develop it with great efforts. Thus it plays an important role in the field of power and transportation.

The industrial gas turbine has developed in two directions: one is specially designed and developed for industrial use mainly heavy-duty; another is the design on the basis of aero-technology or to convert the aeroengines; they are normally lighter in structure, and called light-duty gas turbine (LDGT). After the 1960s, the aero gas turbine engines have made rapid progress, and the related technology has reached a mature stage. The reliability and economy are greatly improved, the compression ratio is about 25, and TET reaches 1,400°C .That is one generation ahead of the ground heavy-duty gas turbines. Therefore, most of the industrial and marine light-duty gas turbines are modified and developed from aeroengines. In this way, it can take the advantage of the advanced technology achieved by the aviation industry with a lot of manpower, material, money and time. In the industrial countries, all successful aeroengines have their industrial and marine versions.

In the 1960s China started to modify her aeroengines into industrial gas turbine engines. Starting from the 1970s, the gas turbine units derived from WZ5, WJ5 and WJ6 were used in oil fields for trial successfully. In 1981, under the leadership of the Machinery Commission, a gas turbine applied research team was formed, who carried out investigations, presented proposals and forcefully pushed forward the development. Since then a new era of the LDGT extensive development has begun. In September 1985, the LDGT Development Center was set up in MAI, which conducted the management of the LDGT development. They gave priority to energy development and conservation, and transportation. Up to the end of 1986, they had delivered 51 sets (83 units) of industrial gas turbines, which were installed in oil fields all over the country, including Tibet.

An oil field needs to set up its own power supply as its main supply, or the peak° time or emergency supply. If a new oil field is not connected to the normal power supply, an oil field power station is essential. The LDGT power generator group is movable and thus most suitable for the needs of the oil field where fuel supply is convenient. ZEF worked with the Beijing Heavy Electric Motor Factory and produced the gas turbine generator converted from WJ6 engine the YD-2000 container type movable power station, converted from the WJ6 engine. It could be quickly installed and moved, and its power rating was 1,800 to 2,000 kW. It could use light diesel, natural gas and the oil field gas.

Up to 1979, they had produced 17 sets, which were used in every big oil field. Single sets had already accumulated more than 10,000 running hours. The YD-1250 movable power station converted from the WJ5 engine by HEF was also in operation in Xinjiang and Daqing oil fields.

There are a lot of natural gas, oil field gas and oil refinery gas not fully utilized. The heat and electricity generator group converted from WP6 engine by SEF using natural gas. It first produced power and then provided steam through the residual heat boiler. The combined heat utilization rate reached 62%. In October 1984, it formally operated at Daqing oil field. To the end of 1986, it had accumulated 15,000 running hours with an average annual running time of more than 7,500 hours, and generated 62 million kWh and provided 176,000 tons of steam. As LDGT provided sufficient steam, and its temperature and pressure were stable, the recovery of the hydrocarbon gas was greatly improved and the daily output was doubled.' The investment for the generator was fully recovered in less than one year. The operation and maintenance of the power station were managed by SEF, who bought the natural gas from the oil field and sold the electricity back to the oil field. This business was most welcome by the users. In 1986, SEF signed contracts with Daqing oil field and Zhongyuan oil field for the supply of 3 heat and electricity generator groups, 2 of which had already been put into operation successfully.

The Zhonghua Gas Turbine Company, jointly run by the Engineering Thermal physics Research Institute of CAS and XEF, worked with Beijing "Dong Fang Hong" (The East is Red) Oil Refinery Complex to implement an energy saving program on gas-steam combined cycle. They converted the WS9 into a heat and electricity generator, which burned the residual gas from the refinery and generated electricity (4,500 kW), and then used a residual heat boiler instead of the original oil boiler to produce moderate pressure steam for the work process of the Refinery Complex. Thus saving on energy. The Wuxi Aeroengine Research Institute (WARI) also took part in the program. This program had entered the installation and commission¬ing stage by the end of 1986.

Water filling is an important measure to guarantee the stable and high output of the oil field. It consumes about more than 40% of the total electricity of the oil field. The modified gas turbine can directly drive the water pump and make further use of the surplus heat. WARI converted 10 WZ5 engines in to water filling pump units, which were delivered for operation in Xinjiang oil field successfully from 1978. Up to 1985, the accumulated running hours were about 50,000, with the longest more than 13,410 hours for a single set. The water filling pump units converted from the WZ6 engine by JHEF were released for operation in Zhongyuan oil field in April 1985. To the beginning of 1987 it had run 5,000 hours in total and filled more than 410,000 .cubic meters of water. The combined cycle unit converted from two WP6 engines by SEF was also installed in Daqing oil field for water filling and heat supply. The use of LDGT changed the energy utilization structure for water filling and saved energy.

The LDGT as a natural gas compressor powerplant can extensively be used for the compressing and feeding of natural gas, and in the hydrocarbon gas recovery unit. The hydrocarbon gas is the easiest part of the natural gas to be liquified. The natural gas is compressed by the compressor driven by LDGT and it is then cooled in the turbine expander, which in turn cools and liquifies the hydrocarbon gas for recovery. The remaining gas can still be used as chemical material or fuel. ZARI modified and developed the WZ5 engine as a turbo-compressor unit; it was connected with the cooling turbine developed by the Hubei Aero-Accessory Research Institute (HAARI) and formed a hydrocarbon gas recovery unit.. Four units were installed in Zhongyuan oil field; two of them had run 6,127 hours, compressed 62 million cubic meters of natural gas and recovered 5,800 tons of hydrocarbon by the end of 1986. It was estimated that after normal operation, the investment for the total installations could be recovered in two years.

LDGT is small, light weight, needs no water and can burn the nearby natural gas, oil field gas and petroleum and is easily switched over. It is the best powerplant on the off-shore platform. It is reported that some foreign deep sea platforms had 98% of their needed power supplied by LDGT. China has also started to work in this field.

The work involved in energy saving and making full use of LDGT to enable the LDGT to burn poor quality and low heat value fuel and form heat and electricity combined generator group of gas-steam cycle is of high priority. The aviation industry is currently cooperating with the chemical industry in testing and exploring this technique for small chemical fertilizer plants. One of the note-worthy new energy saving subjects is the direct use of coal (after being gasified, slurried or powdered) as fuel for LDGT. Many countries in the world are studying this subject and China is also active in this field.