Steam quality measurement system
A system and method for continually and automatically measuring the quality of steam includes a steam dryness/superheat meter and a non-condensable gases (NCG) meter. The steam dryness meter includes a throttling calorimeter through which a steam sample enters at atmospheric pressure, sensors for sensing the pressure and temperature of the stream before and after it enters the calorimeter, a controllable heat input for supplying any additional energy necessary to superheat the steam sample, and logic for deriving the dryness from the collected data. The NCG meter includes a cooler for condensing the steam sample reservoirs into which the liquid and non-condensable gases are entrapped and measured, and logic for continuously deriving the NCG ratio from the collected data.
1. A system for measuring the quality of steam flowing through a conduit including
a steam dryness meter having a throttling calorimeter, at least one sensor for sensing a thermodynamic condition of the steam upstream of the calorimeter, at least one other sensor for sensing the condition of the steam sample in the calorimeter, and a controllable heat input for applying heat to the steam sample;
a non-condensable gases meter including, a cooler for condensing a superheated steam sample, and a reservoir including an inverted bucket where the condensate and non-condensable gases separate and are entrapped, at least one sensor operably connected to the inverted bucket, at least one other sensor operably connected to the reservoir; and
a computer operably connected to the sensors in the steam dryness meter and the non-condensable gases meter for periodically receiving the data signals corresponding to the sensed steam sample conditions in each of the steam dryness meter and the non-condensable gases meter, the computer including first logic on a computer readable medium, which first logic may be executed by the computer for determining the dryness of the steam sample based upon the sensed steam sample conditions and second logic on a computer readable medium, which second logic may be executed by the computer for determining the ratio of water to non-condensable gases in the condensed steam sample based on the sensed steam sample conditions in the inverted bucket and the reservoir.
2. The system of claim 1 further including a display for displaying the derived dryness and NCG ratio data on a periodic basis.
3. The system of claim 1 wherein the dryness meter includes a pressure sensor for sensing the pressure of the steam upstream of the calorimeter, and a temperature sensor for sensing the temperature of the steam sample in the calorimeter.
4. The system of claim 1 the controllable heater in the dryness meter is an electric resistance heater.
5. The system of claim 1 wherein the sensor operably connected to the inverted bucket is a pressure sensor, and the sensor operably connected to the reservoir is another pressure sensor.
6. The system of claim 1 wherein the computer is a single programmable logic controller.
7. The system of claim 1 wherein the dryness meter includes a calibrated orifice through which the diverted steam sample enters from the conduit without working, the at least one sensor for sensing a thermodynamic condition of the steam upstream of the calorimeter is a pressure sensor, the at least one other sensor for sensing a condition of the steam sample in the calorimeter is a temperature sensor, and the controllable heater is an electric resistance heater.
8. A system for measuring the quality of steam flowing through a conduit includes (1) a diverter for diverting a sample of the steam from the conduit, (2) a steam dryness meter having, a throttling calorimeter including a calibrated orifice through which the diverted steam sample enters from the conduit without working, a pressure sensor for sensing the pressure of the steam upstream of the calorimeter, a first temperature sensor for sensing the temperature of the steam sample in the calorimeter, and a controllable heat input for heating the steam sample, (3) a non-condensable gas meter including a cooler for condensing the superheated steam sample, an injector for injecting the condensed steam into a reservoir including an inverted bucket where the condensed liquid and non-condensable gases are separated and entrapped, a first pressure sensor operably connected to the inverted bucket for measuring the pressure of the entrapped gases, a second pressure sensor operably connected to the reservoir for measuring the pressure of the entrapped condensate, (4) a computer operably connected to the pressure sensor and the temperature sensor in the steam dryness meter and the first pressure sensor and the second pressure sensor in the non-condensable gas meter for periodically receiving the data signals corresponding to the sensed steam sample conditions in the steam dryness meter and the collected condensed water and non-condensable gases in the non-condensable gas meter, the computer including first logic on a computer readable medium, which first logic may be executed by the computer for determining the dryness of the steam sample based upon the sensed steam sample conditions and second logic on a computer readable medium, which second logic may be executed by the computer for determining the ratio of condensate to non-condensable gases in the condensed steam sample, and (5) a display for displaying the derived dryness and NCG ratio data, either on a periodic or continuous basis, as desired.