Abating TAN Levels: Minimac's Tailored Solution for Critical Oil Values at India's 9th Largest Coal-Fired Power Plant

Synopsis

In Singrauli, MP, stands a colossal thermal power plant, one of the largest PSUs and the 9th largest coal-fired power station at 4760 MW capacity. Recently, it faced a formidable challenge - high TAN Levels in two 16kl control fluid tanks. To prevent a potential disruption and subsequent shutdown, Minimac provided a customized solution by deploying a specialized machine to lower TAN levels, address moisture, solid contamination and implement effective Nitrogen Blanketing.

Initial Findings

Two of the control fluid tanks had elevated levels of TAN, Moisture & NAS, which had a direct impact on the Servo Valve Operations.

Oil Values	NAS	TAN	Moisture Level
Control Fluid Tank at UNIT 11	Class 8	0.62 mg KOH/g	561 PPM
Control Fluid Tank at UNIT 12	Class 7	0.52 mg KOH/g	500 PPM

Problems

The client encountered increased TAN levels in two of their Control Fluid Tanks which had a detrimental impact on the operation of servo valves leading to reduced responsiveness, erratic behavior, increased wear and tear, and potential valve malfunction.

Client’s Requirements

• To Purify 32kl of FRF Oil
• To remove the TAN, Moisture and Solid Contaminants.
• To Achieve NAS: ≤ Class 5.
• To Achieve TAN: ≤ 0.10 (mg KOH/g).
• To Achieve Moisture: ≤ 500 ppm.
• Customized Solution.

Solutions

Deploying Minimac’s customized machine at the site along with trained and skilled engineers.

1. TAN Reduction Systems(20 LPM) equipped with the ion exchange resin to filter and eliminate acid components of oil.
2. Low Vacuum Dehydrator (100 LPM) to maintain consistent moisture levels in the oil using the vacuum dehydration ensuring smooth turbine operation in its active state.
3. Oil filtration system(150 LPM) to bring the NAS level of oil to the desired range.
4. Nitrogen blanketing system to maintain an inert space above the oil in the tank, serving as a barrier between the moisture-laden external air and the FRF oil inside the tank.
5. Along with the equipment’s installation, our Service Engineer trained the client’s team on the functioning and effective handling of the machine.
6. Job executed within a limited time-span on the running unit without hindering the client’s operations and control fluid tank system.

Value Type	Control Fluid Tank at UNIT 11		Control Fluid Tank at UNIT 12
	Before	After	Before	After
NAS	Class 8	Class 4	Class 7	Class 4
TAN	0.62 mg KOH/g	0.08 mg KOH/g	0.52 mg KOH/g	0.08 mg KOH/g
Moisture Level	561PPM	275 PPM	500 PPM	184 PPM

Benefits

1. Prevented the environment from harm by averting the emission of 3,84,000 kg of CO2e.
2. Saved 32 kl of Oil from being incinerated.
3. Extended Oil Life.
4. Reduced TAN Levels.
5. Elimination of Oil Replacement Costs.

Cost Saving

This Plant managed to save:

Cost of Oil Replacement: ₹7 Cr. Approx.

Cost of Downtime : ₹1 Cr. Approx.

CO2e Savings

Total Savings =3,84,000 kg of CO2e/0.384 gigagrams of CO2e

Graph

Pictorial Representation

Right to left( LVDH:100LPM, FS :150LPM, TAN Reduction Skid Ion Exchange :20LPM)

Resin Skid-TAN REDUCTION M/C (Ion Exchange 20 LPM)

Before and after oil sample

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