Method and apparatus for achieving higher cooling rates of a gas during bypass cooling in a batch annealing furnace of cold rolling mills

1. A method for achieving a higher cooling rate of hydrogen during bypass cooling in a batch annealing furnace, the method comprising the steps of:

filling a preparation unit with water maintained at ambient condition;

measuring in a first measuring and control device nanoparticles including dispersants at a lot-size determined based on steel coils to be cooled, the first device controlling flow rates, pressure, and temperature of the nanofluid to be supplied to a heat exchanger;

mixing the nanoparticles including the dispersants with the water at a volumetric ratio of 0.01-5% in the preparation unit;

supplying the nanofluids from the preparation unit to a reservoir by using a pump;

delivering hydrogen gas to the heat exchanger at a heated temperature;

delivering the nanofluid at a predetermined flow-rate, temperature, and pressure from the reservoir to the heat exchanger;

supplying cooled hydrogen gas from the heat exchanger to the furnace for cooling heated steel coils;

returning hydrogen to the heat exchanger from the furnace; and

using the nanofluid delivered to the heat exchanger for exchanging heat with the hydrogen;

wherein, the nanofluid exits the heat exchanger via a first outlet, the cooled hydrogen exits the heat exchanger via a second outlet, and the hydrogen is cooled at a higher rate.

2. The method as claimed in claim 1 , wherein the heated gas is caused to pass through the heat exchanger.

3. The method as claimed in claim 2 , wherein the heat exchanger uses the nanofluid as the heat exchange medium.

4. The method as claimed in claim 1 , wherein the nanofluid is water or oil based.

5. The method as claimed in claim 1 , wherein the nanofluid is water or oil based with a stable nanocoolant with higher heat extraction capabilities.

6. The method as claimed in claim 1 , wherein the effectiveness of the heat exchange process using nanofluid is from 5% to 30% improved compared to water at ambient temperatures in the same circuit.

7. The method as claimed in claim 1 , wherein the heated gas is hydrogen at normal or pressurized conditions.

8. The method as claimed in claim 1 , wherein the nanofluid contains nanoparticles in volumetric proportions of 0.1%.

9. The method as claimed in claim 1 , wherein the nanofluid contains titanium dioxide (TiO 2 ) having nanoparticles of sizes varying between 5 to 200 nanometers.

10. The method as claimed in claim 1 , wherein the nanofluid contains a stabilizer agent.

11. The method as claimed in claim 10 , wherein the nanofluid is a stable nanocoolant, the stability being determined by a non-setting period of more than 240 hours.

12. The method as claimed in claim 1 , wherein the flow rate of the nanofluid is from 5 m 3 /hr to 100 m 3 /hr.

13. The method as claimed in claim 1 , wherein the nanofluid is in a pH range of 3 to 12.

14. The method as claimed in claim 1 , wherein the nanofluid is in a temperature range of 10 to 60° C.

15. The method as claimed in claim 1 , wherein the hydrogen is delivered to the heat exchanger at a temperature between 400° to 600° C.

16. The method as claimed in claim 1 , wherein the hydrogen gas is cooled at a rate of 1.0-2.0° C/min.

17. A method for achieving a higher cooling rate of hydrogen during bypass cooling in a batch annealing furnace, the method comprising the steps of:

supplying hydrogen gas from a heat exchanger to a furnace for cooling heated steel coils and returning heated hydrogen to the heat exchanger from the furnace; and

cooling the heated hydrogen gas by exchanging heat between the hydrogen and a nanofluid delivered to the heat exchanger, wherein the nanofluid exits the heat exchanger via a first outlet and the cooled hydrogen exits the heat exchanger via a second outlet,

wherein the nanofluid includes nanoparticles mixed with water.

18. The method as claimed in claim 17 , wherein the nanoparticles are mixed with water at a volumetric ratio of 0.01-5%.