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US 2021/0010200 A1Published application
Vent stack temperature as a feedforward variable for smelt dissolving tank tta control
AssigneeFPInnovations
InventorsBruce James ALLISON, Wei REN, Brennan DUBORD, Jason JOHNSON
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Abstract
Methods and systems for controlling operation of a smelt dissolving tank receiving a flow of smelt and having a vent stack in fluid communication are provided. A dissolving liquid is injected into the smelt dissolving tank at a predetermined injection rate. A temperature of a flow of vapour in the vent stack is measured with a sensor. The injection rate of the dissolving liquid is controlled based on the temperature of the flow of vapour.
Claims20
1:
- A method for controlling operation of a smelt dissolving tank receiving a flow of smelt and having a vent stack in fluid communication with the smelt dissolving tank, comprising:
- injecting, at a predetermined injection rate, a dissolving liquid into the smelt dissolving tank;
- measuring a temperature of a flow of vapour in the vent stack with a sensor;
- and
- controlling the injection rate of the dissolving liquid based on the temperature of the flow of vapour.
2 more elements
2:
- The method of claim 1, further comprising:
- measuring at least one parameter of an output product of the smelt dissolving tank;
- and
- further adjusting the injection rate of the dissolving liquid based on the at least one parameter.
1 more element
3:
- The method of claim 2, wherein the output product is green liquor.
4:
- The method of claim 3, wherein the at least one parameter comprises a density of the green liquor.
5:
- The method of claim 3, wherein the at least one parameter is a concentration of total titratable alkali in the green liquor.
6:
- The method of claim 1, wherein adjusting the injection rate comprises setting the injection rate between a predetermined minimum injection rate and a predetermined maximum injection rate.
7:
- The method of claim 6, wherein at least one of the minimum injection rate and the maximum injection rate is based on a safety requirement.
8:
- The method of claim 1, wherein the dissolving liquid is recycled water from a milling process.
9:
- The method of claim 1, wherein measuring the temperature with the sensor comprises measuring the temperature with the sensor located within the vent stack.
10:
- The method of claim 1, wherein measuring the temperature with the sensor comprises measuring the temperature with the sensor located at an output of the vent stack.
11:
- A system for controlling operation of a smelt dissolving tank receiving a flow of smelt and having a vent stack in fluid communication with the smelt dissolving tank, comprising:
- a processing unit;
- and
- a non-transitory computer-readable memory having stored thereon program instructions executable by the processing unit for:
- injecting, at a predetermined injection rate, a dissolving liquid into the smelt dissolving tank;
- measuring a temperature of a flow of vapour in the vent stack with a sensor;
- and
- controlling the injection rate of the dissolving liquid based on the temperature of the flow of vapour.
5 more elements
12:
- The system of claim 11, wherein the program instructions are further executable for:
- measuring at least one parameter of an output product of the smelt dissolving tank;
- and
- further adjusting the injection rate of the dissolving liquid based on the at least one parameter.
1 more element
13:
- The system of claim 12, wherein the output product is green liquor.
14:
- The system of claim 13, wherein the at least one parameter comprises a density of the green liquor.
15:
- The system of claim 13, wherein the at least one parameter is a concentration of total titratable alkali in the green liquor.
16:
- The system of claim 11, wherein adjusting the injection rate comprises setting the injection rate between a predetermined minimum injection rate and a predetermined maximum injection rate.
17:
- The system of claim 11, wherein the dissolving liquid is recycled water from a milling process.
18:
- The system of claim 11, wherein the sensor is located within the vent stack.
19:
- The system of claim 11, wherein the sensor is located at an output of the vent stack.
20:
- A control system for a smelt dissolving tank receiving a flow of smelt and having a vent stack in fluid communication with the smelt dissolving tank, comprising:
- a sensor configured to measure a temperature of a flow of vapour in the vent stack;
- and
- an injection rate controller configured to:
- receive a reading indicative of the temperature from the sensor;
- and
- control an injection rate of the dissolving liquid into the smelt dissolving tank based on the reading.
4 more elements