Increased Fuel Bills and Excess Steam Consumption in the Distillery?
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A renowned spirit manufacturer’s plant in Western India was facing problems ranging from boiler efficiency to excess steam consumption. This reduced the overall process efficiency and thereby led to monetary losses. Forbes Marshall was approached to help address these problems.

Fact Check

Installing an efficient boiler does not guarantee efficient operations. Surveys reveal that operating efficiency of unmonitored boilers lag behind the rated efficiency by 5%-15%, with fuel bill generally being determined by operating efficiency. Over time, fuel costs amount to more than the cost of the boiler - many times over.

A thorough survey of the plant revealed a drop in boiler efficiency and excess steam consumption at the equipment level. It was also found that flash steam was being vented to atmosphere instead of being reutilised in the process.

The Forbes Marshall Solution
Boiler Efficiency Monitoring

The first step towards improving boiler efficiency is to understand its current operating efficiency. To effectively analyse parameters affecting the boiler efficiency, EffMaxTM, the total online boiler efficiency monitoring system was installed.

The EffimaxTM system measures important parameters like steam flow, fuel flow, etc on the basis of which parameters like boiler efficiency, steam to fuel ratio, etc. are calculated. Parameters like stack emissions, drum level , drum TDS, etc can also be controlled with the help of the EffiMaxTM.

With the installation of the EffiMaxTM, it was found that the boiler was operating at high oxygen levels of 12%, which severely impacted boiler efficiency.

Using actionable insights from EffimaxTM

  - Oxygen levels were brought down and maintained at 9%

  - Feedwater temperature was increased from 54 degree Celsius to 65 degree Celsius.

Boiler specific standard operating procedures were put in place to not only bridge the efficiency gap but also sustain the efficiency level over the entire operating life of the boiler.

Measured Parameters Calculated Parameters Control Parameters
Steam Flow Boiler Efficiency Stack Oxygen
Fuel Flow Steam to fuel ratio Drum TDS
 Steam Pressure Stack Loss   Drum Level
 Steam temperature  Blowdown loss Water tank level 
 Stack temperature  Enthalpy loss  Deaerator level
 Ambient temperature  Radiation loss  Deaerator pressure
 Feedwater temperature Blowdown quantity   
 % of Oxygen in flue gas & Blowdown TDS    
Optimum pressure reduction

The issue of pressure drop was addressed by installation of a robotic pressure reducing valve at the 10KLPD distillation unit to ensure steady pressure.

For the improvement in steam distribution a pressure reducing station was installed, the line size was corrected and also drain traps were installed to ensure proper condensate evacuation through the distribution line.

Appropriate steam trapping

Existing steam traps on the reactors in the distillation unit were replaced with two orifice float traps, thereby eliminating the need to keep the bypasses open.

Condensate and flash steam recovery

Flash steam from the two distillation units of capacity 20 KLPD & 10KLPD, was being vented out. A FlashJetPumpTM was installed to recover the flash steam which was then utilised in the FOC column and used to preheat feedwater as well.

Implementation of the suggestions made by the Forbes Marshall team, and installation of energy efficient products from the Forbes Marshall range resulted in improvement in condensate recovery factor from 45% to 88% and specific steam consumption from 3 to 2.7kg/ltr ETA.