Abstract:
This process pertains to a achieving high on-stream time and maintaining the temperature and composition of the raw effluent gas stream from a partial oxidation gas generator being fed simultaneously with a stream of gaseous fuel and separate stream of liquid hydrocarbonaceous fuel. Two parallel oxygen streams equipped with flow transmitters and control valves are used to supply the oxygen associated with two separate and different fuel streams. Each stream of oxygen is controlled by an O.sub.2 /fuel ratio control so that if the flow rate of either stream of fuel or its related oxygen stream changes, the oxygen/carbon atomic ratio of the remaining O.sub.2 and fuel stream in the gasifier is maintained at a desired value. Further, if either fuel flow is stopped, its associated O.sub.2 flow will stop, but the remaining fuel stream and its associated O.sub.2 stream will continue to flow at the same rate with no change in the oxygen/fuel weight ratio. Complete shut down of the unit is thereby avoided. The quick raising of reactor temperatures to unsafe levels due to excess oxygen that occurs when one of the fuel streams is lost is thereby prevented.
Abstract:
A gas accident preventive unit has a memory circuit which is capable of memorizing in advance a continuous service safety time according to a consumed gas volume of gas apparatuses that are installed at a gas user. The unit also includes a control circuit for sending out to an emergency shutoff valve, a close signal for cutting off the gas being supplied to the user in the event that any increase in gas flowrate is recognized in the previously measured value and the value measured this time by taking a measurement of the whole gas flowrate value being supplied to the gas user at a certain interval of time. The unit takes the measurement of continuous service hours on individual gas apparatuses or the gas apparatus having the largest gas consumption volume now under service, or responds to when the service of gas apparatus with the largest gas consumption volume being monitored has elapsed the continuous service safety time.
Abstract:
The fuel constitutes a fixed bed in the reactor, which is provided in its lower portion with a rotating grate, which is adapted to be speed-controlled. The gasifying agents consisting of oxygen, steam and/or carbon dioxide are introduced through the rotating grate into the fixed bed. Under the action of the rotating grate the incombustible mineral constituents are delivered as solid ash to a lock chamber container. The speed of the rotating grate is controlled in dependence on the temperature in the lock chamber container. The speed will be decreased when the temperature in the lock chamber container exceeds a desired value, and increased when the temperature is too low. The desired temperature in the lock chamber container is taken into account as a range, which varies with time. The speed can be controlled by hand or can be automatically controlled with the aid of a computer. The rate at which oxygen as a gasifying agent is supplied to the reactor is also taken into account in the speed control.
Abstract:
A partial oxidation control system for continuously producing synthesis gas, fuel gas or reducing gas in which one process fuel is replaced by a different fuel without shutting down or depressurizing the gas generator. Suitable burners for introducing the feedstreams into the gas generator comprise a central conduit means radially spaced from a concentric coaxial outer conduit having a downstream exit nozzle, and providing a coaxial annular passage means therebetween. The central conduit means may be retracted upstream from the burner face a distance of about 0 to 12 and preferably 3 to 10 times the minimum diameter of the central exit orifice. A premix zone is preferably provided comprising one or more, say 2 to 5 coaxial chambers in series where substantial mixing of the reactant streams and optionally volatilization of the slurry medium takes place. A control system is provided for switching the type of reactant fuel stream flowing through either the central conduit means or the annular passage means of the burner and adjusting the flow rates of the reactant stream of free-oxygen containing gas with or without mixture with a temperature moderator and if necessary to introduce supplemental H.sub.2 O into the reaction zone to maintain the temperature and weight ratio H.sub.2 O/fuel in the reaction zone at design conditions for the partial oxidation reaction without stopping production of the product gas.
Abstract:
Trim control of a partial oxidation gas generator for the production of synthesis gas, reducing gas, or fuel gas is effected by two improved control schemes which are automatically operated separately or in sequence. The control systems include sensors sensing the flow rate of the feedstreams and analyzers which provide signals corresponding to the wt. % carbon in the effluent gas quench cooling and scrubbing water for use in controlling the particulate carbon in the effluent gas stream, and/or signals corresponding to the mole fractions of CO.sub.2, CH.sub.4, CO and H.sub.2 (dry basis) in the cooled and cleaned effluent gas stream for use in controlling the temperature in the reaction zone. The signals from the sensors and analyzers are provided to the system control unit which computes values that represent the relative difference between the actual and desired carbon-make and/or the actual temperature in the reaction zone, and the relative difference between the actual and desired temperature in the reaction zone. The actual temperature is determined as a function of the methane equilibrium constant. These values are automatically compared with set point values and when adjustments are necessary, signals from the system control unit are provided to a flow rate regulating means which adjusts the flow rate of the free-oxygen containing gas by a small determined amount for control of the particulate carbon and/or to a flow rate regulating means which adjusts the flow rate of the temperature moderator by a small determined amount for control of the temperature in the reaction zone.
Abstract:
An ash level control system is provided which incorporates an ash level meter to automatically control the ash bed level of a coal gasifier at a selected level. The ash level signal from the ash level meter is updated during each cycle that a bed stirrer travels up and down through the extent of the ash bed level. The ash level signal is derived from temperature measurements made by thermocouples carried by the stirrer as it passes through the ash bed and into the fire zone immediately above the ash bed. The level signal is compared with selected threshold level signal to determine if the ash level is above or below the selected level once each stirrer cycle. A first counter is either incremented or decremented accordingly. The registered count of the first counter is preset in a down counter once each cycle and the preset count is counted down at a selected clock rate. A grate drive is activated to rotate a grate assembly supporting the ash bed for a period equal to the count down period to maintain the selected ash bed level.In order to avoid grate binding, the controller provides a short base operating duration time each stirrer cycle. If the ash bed level drops below a selected low level or exceeds a selected high level, means are provided to notify the operator.
Abstract:
A method of hydrogenation of unsaturated hydrocarbons for syngas production is presented. A hydrogenation feed reactor stream is introduced into a hydrogenation reactor, thereby producing a reformer feed stream. The reformer feed stream is introduced into a reformer, thereby producing a crude syngas stream. The crude syngas stream is introduced into a water gas shift converter, thereby producing a hydrogen-rich stream. The hydrogen-rich stream is separated in a separation means, thereby producing a carbon dioxide-rich stream and a hydrogen product stream. At least a portion of the hydrogen product stream is combined with a refinery fuel gas stream, and a natural gas stream, to form the hydrogenation reactor feed stream.
Abstract:
In a rotary-grate gas producer operated under a pressure from 10 to 100 bars, the fuel constitutes a fixed bed, which slow descends. The mixture of gasifying agents contains water vapor and oxygen is supplied to the fixed bed through a rotary grate and through an ash layer, which is disposed on the rotary grate. In order to ensure that the ash will have a particle size in a desired range, a first pressure (p1) is measured below the rotary grate and a second pressure (p2) is measured approximately at the top of the ash layer. The pressure difference (p1-p2) is compared with a setpoint, which is associated with the current ratio of water vapor to oxygen in the mixture of gasifying agent. Said ratio is increased when the pressure difference is insufficient and the ratio is decreased if the pressure difference is excessive.
Abstract:
A process for monitoring the conditions in the reaction zone of a gasifier in a process for the gasification of coal to produce synthesis gas is disclosed, the process being characterized by continual or periodic calculation of the rate of steam production by the heat exchange system of the gasifier, and comparison of the calculated rate with a pre-selected value.
Abstract:
This invention relates to a two-fluid nozzle which is adjustable to provide a substantially constant mixing energy. Adjustment of the two-fluid nozzle is made in accordance with the pressure and mass flow values of the liquid and gas fed to the nozzle. A microprocessor calculates the mixing energy from these values and provides an output to the nozzle to adjust it should its mixing energy be in variance with a pre-selected mixing energy.