DE102006033994A1 - Steam turbine generator for marine use taps energy from surplus steam for on-board general use - Google Patents

Abstract

Claimed is a process to tap surplus low-temperature steam from a marine diesel engine general on-board steam supply, and drive an electricity turbine generator. The turbine generator speed is regulated by the demand for electrical power. The turbine generator is fully encapsulated. The capsule has no apertures for shafts. The generator is steam-cooled.

Description

Of the needed on board for heating Steam is used in sea mode in an exhaust gas boiler from the waste heat of Engine exhaust generated. The interpretation of these exhaust gas boiler is made after a steam balance or after years of experience of the Shipyard and shipping company. Because the ship is not only at the design point operated, resulting in operating points in which the exhaust boiler too much or too little steam is generated. In both, from the design point deviating, states will be additional Energy needed to generate the missing steam or the excess steam to condense.

On Ships the heating steam for the machine operation for the heating of heavy oil in tanks and bunkers and for preheating in separator and final preheaters needed. For the general ship operation is heating steam for heating, air conditioning and for the hot water supply used.

The Heizdampfverbraucher can according to the temperatures of the media to be heated in high-temperature (HT) and low temperature consumer (NT) are distinguished. Consumers in which media to temperatures below 100 degrees C are heated, they are called NT consumers. Just the final preheater, in the heavy oil dependent from the viscosity heated to 120-140 degrees C, is thus as an HT consumer Are defined. The final preheater as well as the important NT consumers are regulated. The required amounts of steam are dependent from the operating mode (sea, port or port operation), of the ship type and the respective trade area. Therefore, to determine the steam demand created a steam balance, wherein the steam consumers accordingly the operating mode with the consumption values are entered.

The Design conditions refer to an engine load point and on extreme outdoor conditions (eg air -20 Degree C water 0 degrees C). The ships are operated worldwide, with higher air and water temperatures at the same main engine power to one higher Produce steam in the flue gas boiler. The steam consumption, however, decreases due to lesser Losses.

Thereby in most cases too much steam generated in the excess capacitor neither liquefied must become. This is additional electrical Energy needed to drive the seawater pump. In case of overproduction not just the cooling water pump more cooling water promote, but The feed pump also feeds the excess condensate back to the steam cycle.

in the 1 the heating steam system of a motor ship is shown schematically. The steam generator cycle consists of the exhaust-gas heated exhaust gas boiler ( 1.1 ), the circulation pumps ( 1.2 ), the combined evaporation drum ( 1.3 ) with the auxiliary boiler and the connecting pipes with various fittings.

The consumer cycle starts with the steaming drum. From here, the steam flows through the main steam line via the control valve 4 to the various steam consumers, the 1 are only indicated. Behind the steam consumers steam traps steam traps ( 1.11 ), which cause a complete release of the heat of vaporization. Consumers use condensate with the condensate pump ( 1.13 ) into the combined feed water filter tank ( 1.12 ).

The feed water tank serves as a buffer and for cleaning the refluxing condensate of dirt. Above the feedwater tank is the excess steam condenser ( 1.10 ), the z. B. is cooled by the Seekühlwasserkreislauf. If more steam is generated than consumed, the excess steam regulator ( 1.6 ) depending on the vapor pressure, an opening of the steam excess valve. In this way, or through control valve 5, the steam flows into the excess condenser and after condensation into the feedwater tank.

The feedwater pumps ( 1.14 ) Feed the feed water from the feedwater tank back into the evaporation drum, closing the consumer cycle. The feedwater pumps are switched on or off by the two-point water level control.

The Regulation of the heating steam system is currently dependent on the vapor pressure. Will be in Exhaust gas boiler generates too little steam, the vapor pressure drops below one lower pressure limit. It is switched on the auxiliary boiler, the with liquid Fuel is heated.

exceeds the amount of steam produced the steam demand, the vapor pressure increases in Steam system and from an upper pressure limit is too much generated Steam in an atmospheric condenser liquefied. This way of regulating the upper vapor pressure is very often used. Known, however, the following regulations are only occasionally applied.

1. Overflow control

• as described

2nd sliding pressure control

The The amount of steam produced is determined by the sliding vapor pressure affected. As the pressure increases, the boiling temperature of the Working fluid, at constant exhaust gas temperature decreases the effective temperature difference and steam production decreases. This Self-regulating behavior is due to the required high vapor pressures and the associated construction costs are not applied.

3. Bypass control

With an exhaust flap and a parallel to the exhaust gas boiler installed Exhaust pipe, a portion of the exhaust gas mass flow past the exhaust gas boiler become. The effect of lower flow rate in this operation a stronger pollution. Therefore, this procedure should only apply to plain tube boilers.

4. Heating surface control

4a. Smoke tube boiler, water level control

at Flue tube boilers leaves the active heating surface influenced by the water level. A water level reduction causes a reduction of the active heating surface and thus a reduction the amount of steam generated in the exhaust gas boiler. Because of the caused thereby Corrosion of the tube bundles on the water side this regulation is not applied.

4b. Water tube boiler, switching off heating coils

at Water tube boilers are heating coils individually or in groups Valves shut off. Dependent from the number of turn-off heating coils results in a Grading of the controlled variable. In the case a fire is no heat dissipation of guaranteed shut off coils.

5. Circulation quantity control (water tube boiler)

With a bypass or a speed adjustable circulating pump let yourself affect the amount of steam generated with the Umwälzmassenstrom. The biggest effect is achieved when the circulation mass flow the amount of steam generated falls below. The in the residual evaporation Deposited salts of the boiler water lead to the reduction of the cross section and thereby tend to blockage.

It is known, the steam generated in the exhaust gas boiler on motor vessels relax in a turbine and then condense at low pressure. Such turbogenerators consist of a turbine, a reduction gear, a generator and are then installed when the generated electrical power is sufficient to reduce the e-consumption in the marine operation cover up. In order to achieve this, it must be possible to produce from the exhaust gases Be large amount of steam and are high efficiencies of the turbine of the gearbox and the generator required.

The Steam system of these plants is divided into a heating steam system and a system for supplying the turbogenerator, the steam of this system is generally overheated in the exhaust gas boiler. Because of the high Investment for a turbogenerator plant to meet the e-needs in the marine operation and in the Usually too little steam generation are so far very few motor ships Equipped with steam turbogenerators.

The invention is based on the object, the previously unused excess steam mass flows in small cheap generator turbines ( 1.7 ) to convert into electrical energy, instead of liquefying this excess steam as previously mainly with additional electrical energy.

According to the invention, it is proposed to switch a generator turbine into the steam system in order to utilize part of the enthalpy of steam and to generate electrical energy. The generator turbine with the NT consumers is parallel to the end preheater ( 1.4 ), so that high steam temperatures are ensured for the final preheater. The viscosity of the heavy oil heated in the final preheater is regulated in the control valve 1 (FIG. 1.9 ), the steam mass flow passing through the final pre-drafter is adjusted depending on the heavy oil viscosity.

The steam mass flow for the NT consumers ( 1.5 ) thus flows through the generator turbine in sea operation and is partially relaxed here. The steam mass flow then flows through the NT steam consumers and releases the remaining heat of vaporization to these consumers. If the steam generation in the exhaust gas boiler is too high, the valve 2 is opened, a part of the steam then flows into the excess condenser for liquefaction. In harbor and turf operation the valve 3 is closed, additional steam is generated in the auxiliary boiler. this steam flows through the now open valve 4 directly into the NT steam consumers.

The generator turbine is schematically in 2 shown and consists of a housing 2.1 and a rotor 2.2 , which is at the same time moving blade carrier and pole wheel. The cooling of the generator is carried out with condensing saturated steam, the generator losses are not lost, but remain in the heating steam system. The speed adjusts depending on the steam mass flow and the generator load. The speed proportional frequency of the generator is converted in a frequency converter to the mains frequency and transferred to the electrical system.

The particular advantages of the invention are that a simple little maintenance-intensive generator turbine electric Energy from excess steam produced, which so far with additional electrical energy consumption must be liquefied.

Claims (5)

Arrangement for using the surplus energy of exhaust gas stoves and to improve the energy balance in diesel engine systems, characterized in that a portion of the steam generated by the exhaust gas is supplied via a generator turbine to the steam consumers with low temperature level, wherein the speed of the generator turbine is set via the electrical power. Generator turbine for converting steam energy into Electrical energy, in particular according to claim 1, characterized that the generator turbine is complete is encapsulated and no shaft passage and shaft seals has and that the blade carrier at the same time magnetic yoke and carrier of the turbine Permanent magnets for the generator excitation is, with the cooling of the generator windings takes place through the outlet steam. Inverter for transfer the electrical power generated in the generator turbine to the Vehicle electrical system according to claim 3, characterized in that in in itself known manner, the generator AC voltage variable frequency in the On-board voltage fixed frequency is converted, wherein the inverter the pressure in the steam system in the specified by a control unit Limits regulates. Arrangement according to claim 3, characterized that the setting of the inverter is done so that the Frequency, voltage and current of the generator calculated maximum possible electrical Power is delivered to the electrical system, with a lower limit by the pressure of the steam leaving the generator turbine is given. Arrangement according to claim 2, characterized that by an electrical device, the frequency of the voltage and / or the current is measured. When exceeding a fixed predetermined Frequency is triggered by the trip, the power supply the electrical device and the associated control organs from the Generator voltage and / or the current takes place.