摘要:
A control system is disclosed for a noninteracting control and protection of a dynamic compressor having rotating vanes.The method consists of a junction of a few control circuits for controlling the performance of a dynamic compressor, for protecting compressor from approaching dangerous zones of operation, and for maintaining a required mass flow rate of a gas through the compressor.An automatic control system based on using the above method is distinguished by its simplicity, great transient and steady state precision and high reliability of surge protection.
摘要:
A method and apparatus for protecting a dynamic compressor from surge. The method includes a first step for providing a simultaneous control of a smaller relief means and a main control member of a dynamic compressor or the driver thereof for changing the performance of the compressor. This combined action provides for the protection from surge and at the same time insures the invariability of the main control parameters of pressure, mass flow rate to the user, or the speed of rotation. The second step provides for controlling a larger relief means and provides for antisurge protection in those cases when the first step is not sufficient to protect the compressor from surge. Apparatus is also provided for automatically implementing the method.
摘要:
A method is disclosed for a cascade control of a dynamic compressor to maintain a constant mass flow rate to a process. The method consists of a successive junction of control loops for controlling the speed of rotation, the pressure in the delivery, and the mass flow rate; the output signal of each outer loop being the input signal for the inner loop and each of the loops containing a compensating element to reduce the effects of large time constants of all previous loops.An automatic control system based on using the above method, distinguished by its great static and dynamic precision in maintaining a controlled parameter, and by the high reliability of protection of the compressor from surge, and protection from a dangerous increase of the speed of rotation and of a dangerous increase of the discharge pressure.
摘要:
A control system is disclosed for a cascade control of a dynamic compressor having a variable speed of rotation to maintain a constant pressure to a process. The method consists of a successive junction of control loops for controlling the speed of rotation, the flow rate of a compressor, the pressure in the delivery or in suction; the output signal of each outer loop being the input signal for the inner loop and each of the loops containing a compensating element to reduce the effects of large time constants of all inner loops.An automatic control system based on using the above method, distinguished by its great transient and steady state precision in maintaining a main controlled parameter, and by the high reliability of protection of the compressor from surge and from a dangerous increase of the speed of rotation.
摘要:
A fuel supply to unit pump-injector systems of diesel engines includes a gasification and saturation of the liquid diesel fuel. A first fuel line delivers the fuel to a low pressure pump driven by an engine shaft which pumps the fuel to a common low pressure fuel manifold. There, the fuel is distributed for injection by the pump-injector units of the engine cylinders. A second fuel line delivers the fuel to a feed pump that feeds through a plurality of nozzles into a gasification vessel. The vessel is pressurized with a gas (e.g., carbon dioxide, air, etc.) a pressure level P2. There, the fuel is saturated with pressurized gas, which is dissolved in the fuel. The solution is then pumped by a second electro motor driven pump that further increases the solution pressure up to a level P3, which is higher than the pressure level P1. At that point, the solution becomes under-saturated and it is fed to the fuel manifold for injection into the engine. A feedback system for the fuel with further pressure and temperature control is provided by the system. The system, and specifically its pumps and the fill level of the gasification vessel, is controlled by a control system.
摘要:
A fuel is aerated in a fuel supply and gasification system for more efficient combustion in a combustion chamber. The gasification system includes a mixing device for mixing a liquid fuel with at least one gas. A gas source feeds the gas to a gas feeding nozzle and through the nozzle further to the mixing device, wherein the gas is mixed with the liquid fuel for forming a liquid fuel/gas bubbles mixture. A low-pressure fuel pump connected with the mixing device by a liquid fuel supply line feeds liquid fuel from a fuel reservoir to the mixing device at pressure P1 higher than the gas pressure P2. A prepared liquid fuel/gas bubbles mixture is fed into a high-pressure fuel pump where the liquid fuel/gas bubble mixture get compressed to the state of homogeneous liquid and further is injected into a combustion chamber for instance of internal combustion engine at a pressure P4 that is higher than a pressure P3 in the combustion chamber at the moment of injecting fuel in it. Finally, there is provided an electronic control system comprises electronic variable frequency pulse generator electrically connected with electrically operated gas feeding nozzle.
摘要:
A method and apparatus are disclosed for protecting gas turbines (two- and three-shaft) from damage or destruction during dangerous transients. In this situation, fuel flow must be reduced, as needed, to keep the exhaust gas temperature below a maximum limit, thereby avoiding damage to blading in the turbine's first-stage. The dynamic action of the temperature downstream of the combustion chamber may be estimated and then used to correct the temperature measured by thermocouples. For this approach, the turbine is instrumented with an inlet pressure transmitter and an outlet temperature transmitter. The method dynamically estimates temperatures downstream of the combustion chamber and reduces the fuel flow rate if the estimated temperature approaches the temperature limit. Existing thermocouple measurements (EGT) are used as well as the pressure of air exiting the compressor (CDP) upstream of the combustion chamber. By employing a first-order lag and a steady-state gain, the measured CDP is used to predict a "correction" EGT signal which is then added to the measured EGT, resulting in a corrected EGT. Once the corrected EGT has been calculated, its first time-derivative is used to adjust the safety margin between a maximum allowable limit temperature and a lower predetermined temperature set point.
摘要:
A method is disclosed for the improved operation of heating stoves for blast furnaces. This method is comprised of a combined use of an independent source of compressed air and potential and thermal energy of air remaining in the heating stoves at the end of a period of cooling. The purpose of this method is to reduce the time of filling of the ready to go on -- wind stoves by compressed air; to stabilize the operating conditions of the blast furnace; to save coke; to save the fuel spent on heating the stoves.
摘要:
A fuel is conditioned in a fuel supply system for more efficient combustion in a combustion chamber. The conditioning system includes a fuel vessel for fuel conditioning, at least one fuel dispersing nozzle mounted for discharge into the fuel vessel, at least one gas inlet port and at least one conditioned fuel outlet. A low level sensor registers a lower level of conditioned fuel in the fuel vessel. A high level sensor registers an upper level of conditioned fuel in the fuel vessel. A gas source feeds a gas to the fuel vessel, wherein the gas is dissolved in the liquid fuel for forming a liquid/gas fuel solution. A low-pressure fuel pump and a liquid fuel supply line supply liquid fuel from a fuel reservoir to the at least one dispersing nozzle of the fuel vessel at a pressure P1 higher than the gas pressure P2. A needle valve positioned downstream the fuel chamber, lowers the pressure, created in the fuel chamber by gas pressure P2, to lower level P3 downstream the needle valve. A resulting over-saturation causes gas to escape from solution. A high-pressure fuel pump feeds the homogeneous liquid into a combustion chamber at a pressure P4 that is higher than a pressure P5 in the combustion chamber at a moment of combustion. Finally, there is provided an electronic control system connected to receive a signal from the low level sensor and from the high level sensor for controlling the fuel level in the fuel chamber.
摘要:
This invention discloses a method for limiting a critical variable (such as, discharge pressure or suction pressure or pressure ratio) of either a compressor station or an individual compressor when these machines are subjected to large, fast disturbances. Each configuration, whether a station or an individual compressor, is equipped with two PID controllers: (1) a main controller for compressor critical variables and (2) a limiting controller that participates in modulating recycle valves. At the onset of sudden, large changes of mass flow at a compressor's or station's discharge, the effectiveness of the two controllers (acting independently) may be insufficient to prevent discharge pressure from reaching the shutdown set point which, in turn, disrupts the process supported by the compressors, and the longevity of the drivers is diminished. For these reasons, this disclosure relates specifically to a technique that combines the functions of the main and limiting controllers. Because of the complementary (synergistic) interaction of the controllers, an earlier and faster opening of the antisurge valves is initiated, and pressure at the discharge header is effectively limited.