Success

At Pennant, no project is too small and no client too far. We have serviced clients across industries, across the globe. While every project is critical, some have posed challenges that we overcame or some are unique simply because of the scale of operations or some because of the tight deadlines we worked within. Each project teaches us a new lesson and serves as a stepping stone towards bettering our services.

Here are a few of our select projects that are dear to us.

reliance logo

Reliance Silvassa Project

Region: India
Industry: Recron Stretch, Linen Like, Melange, Thick-n-thin and Bi-shrinkage yarns manufacturing
Solution Type: Steam Tarp – PT67
Customer: Reliance Industries Ltd.
Location: Reliance Silvassa Project

Background
Reliance was setting up a major plant at Silvassa. Its Manufacturing Division was located in the Union Territory of Dadra and Nagar Haveli. It was being setup to manufacture a wide range of specialty products such as Recron Stretch, Linen Like, Melange, Thick-n-thin and Bi-shrinkage yarns.
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They appointed Chemtex as their consultant for the project. Chemtex made a comprehensive detailing of the project and divided the complete plant functioning into 3 sub processes namely – start-up process, standard functioning and shut-down process.

The processes were setup in such a way that the start-up and end process would come into picture only when the plant had to be shut down for maintenance and at start-up. Both these processes were very important and crucial for smooth working of the plant and also for smooth shut-off.

At the start-up process, Reliance was going to use DOWTHERM* A as the heat transfer fluid. DOWTHERM* A solution is a eutectic mixture of two very stable organic compounds, biphenyl (C12H10) and diphenyl oxide (C12H10O). These compounds have practically the same vapour pressures, so the mixture can be handled as if it were a single compound.

To handle this solution Chemtex had a requirement of a trap that could work at 0.1bar differential pressure to handle a condensate load of 22,000 kg/hr . They also had an area constraint due to which they needed a single trap with the above specifications. They approached various trap manufacturers with this requirement. Most of the trap manufacturers denied the enquiry as according to their design, they would have to install 3 traps in parallel arrangement to satisfy this requirement.

Scope of Work
During this process Chemtex approached Pennant as well with the requirement. Pennant’s team of experts who handle enquiries for special traps, immediately accepted the challenge to make a sole trap for Reliance that would satisfy the desired condition. A detailed study – calculations, permutation & combinations, and hard work was put in by the team to come up with the new design of PT67 that would satisfy the need. After the trap was designed, the challenge was to actually manufacture the trap. Every minute details had to be taken care off as it would directly affected the production of trap.

Appropriate desired internals, body material and ideal assembly are the most important needs of any trap to function properly. Pennant’s internals and material of construction were appropriate for this trap.

We chemically tested these internals after which multiple tests were performed on material of construction to ensure they were acceptable.

After receiving all the raw material for the products, Pennant started manufacturing this trap. Microscopic specifics during manufacturing and assembly were taken care of by the experts at all stages. Pennant was finally ready with their trap which would satisfy Reliance’s requirements.

Various tests had to be performed on the trap to ensure that the custom made special trap given to Chemtex was faultless. We approached a NABL approved laboratory to perform the most crucial test i.e. discharge capacity measurement test which would articulate if the trap could handle such high load was cold water test. Later a functional test was performed on the trap to ensure there was no leakage in the trap. After both the test were positive the team was sure that the trap was ready to handle 22,000 kg/hr condensate load at 0.1 differential pressure.

Chemtex then sent a third party inspector for inspection. They checked the trap minutely and certified that the trap would function in the desired condition.

Benefits
Pennant’s PT67 is a compact assemble trap that could work at 0.1bar differential pressure to handle a condensate load of 22,000 kg/hr. No other manufacturer could develop a single trap to meet this requirement. Due to this Reliance did not have to take a complex bulky setup to suite their requirement but instead got a solution in one single trap. Pennant’s PT67 was installed at their Silvassa project 2 years and is working perfectly fine in all extreme conditions.

rice mills

Steam Traps in Rice Mill

Steam Traps play a major role in Rice Mills especially for Para Boiling.

Commonly used dryers:-

  1. 24 Ton
    Requirements of Steam at a pressure of 4 to 6 Kg/cm² is 1100 to 1300 Kg/hr at 4 Kg/cm²
    Inlet to Drier should be 3” which can carry said amount of Steam required for efficient drying
  2. 32 Ton
    Requirements of Steam at a pressure of 4 to 6 Kg/Cm2 is 1400 to 1600 Kg/hr at 4 Kg/Cm2
    Inlet to Drier should be 4” which can carry said amount of Steam required for efficient drying.

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Trap Sizing
A 40MM Ball Float Steam Trap is suitable for these dryers, as at a differential pressure (Inlet – Outlet) of 4 Kg, it can drain up to 3526 Kg/hr. At 0.5 Kg differential pressure it can give 2234 Kg/hr meeting our requirements for the condensate flow.

Note: During start-ups and shut downs, all the steam in the system condenses and turns into water. It is very important to drain this condensate out of the system as it will not allow fresh Steam/Condensate to come in the dryer. This massive condensation increases the Draining Load to twice the actual load. Hence we recommend Steam Trap with a higher capacity of 3526 Kg/hr, even though Condensate that has to be drained during normal process is only 1100 to 1600 kg/hr.

Trap Module:
An assembly of 2 Globe Valves, a Strainer, a Steam Trap and a Disc Check Valve is termed as a trap module.

‘Y’ type Strainer should always be used in upstream of Steam Traps and Disc Check Valve at downstream. By using 2 of Globe Valve we can have a bypass line for cleaning/servicing of Steam Traps and Strainers.

Note: WE SUGGEST, DO NOT USE THE BYPASS LINE TO HURRY THE PROCESS AS THIS MAY RESULT IN WASTAGE OF STEAM. USE IT ONLY TO REPAIR OR SERVICE THE TRAP

FLUSHING THE SYSTEM
It is essential to flush the system when we are commissioning a plant, as welding chips and other foreign particles can damage the seat of Globe Valve and Steam Traps. One should always remove the trap modules before flushing the systems.

FIRST- STEAMING- KACCHI

Background:
Rice is naturally sealed with an Air Jacket to keep it fresh. Live steam at maximum temperature/pressure of 98˚C/3 bar has to be given during Kacchi process to puncture the Air Jacket of the Rice thus increasing porosity.

Direct steam injection done to paddy is for 2.5 to 3 minutes.

Common Mistakes Encountered:
People commonly use steam at 7 to 8 Kg/cm² (162-168˚C) which results in giving much higher temperature and pressure than required, in turn damaging grains in following manner:-

  1. It results in blackening/de-coloration of the rice.
  2. High pressure with high temperature make the rice crack in turn increasing breakage
  3. Wastage of energy and money

We recommend:
In order to avoid the above possibilities we strongly recommend a Pressure Reducing Valve, especially for first Steaming Kacchi and Pakki processes, to reduce the steam pressure from 10 to 3Kg/cm². At 3 kg/cm² the temperature of the steam will be Maximum 130˚ C. An effective heat transfer to grains will increase the temperature of grain to 98 degrees. This will result in drastic reduction in blackening/de-coloration, broken grain and in-turn save energy and money.

Soaking
Soaking is a process of keeping the paddy in a water tank for 8 hours at 60˚C to increase the moisture content to 30%- 33%. Soaking will help in gelatinization of the starch available in rice.

Note: Starch gelatinization is a process of breaking down the intermolecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. This permanently dissolves the starch granule in water making the rice healthier

Second Steaming (Pakki)

Background:
Direct steam injection is done to paddy for 2.5 to 3 minutes.

Second Steaming is done to repair cracks present in the grain which eventually reduces the breakage and start of gelatinization process.

Note: STEAM PRESSURE SHOULD NOT BE MORE THEN 3 BAR. IF THE STEAM PRESSURE IS ABOVE 3 BAR IT WILL HAVE OPPOSITE EFFECTS.

PARA BOILING
The process of gradually reducing moisture content from 33% to 12% is called Para Boiling. It is done in 6 stages.

Stage
Temp.in degrees
Duration In hours
Moisture Content at start
Moisture condensate at end
Valve opening
Steam Pressure-bar
1
130
4
33%
20-22%
100%
4
2
100
1
20-22%
21-20%
80%
3.5
3
90
1
20%
19%
60%
3.0
4
80
2
19%
17%
40%
2.5
5
70
2
17%
15%
20%
2.0
6
60
3
15%
12%
10%
0.5 to 1 bar

We achieve the above temperature by closing the inlet valve proportionately and by reducing the Temperature.

VACUUM & STALLING
We recall the basics of steam properties – if we convert 1 kg of water in steam the volume occupied by the steam will be 11 times the volume occupied by the same amount of water. In-Reverse if we condense the steam it will reduce 11 times in volume.

During the last stage when we close the valve (90% close) the low pressure results in massive and rapid condensation in the heat exchanger. This results in sudden drop of volume and can sometimes give rise to vacuum (-0.3). Chances of vacuum are significantly high during Winter/Rainy Season.

  1. EFEFCTS OF VACUUM & STALLING
    Condensate will not get drained irrespective of the trap, as no Trap or “APT” can work under Vacuum conditions.
  2. Water Hammer
    Water starts accumulating in the heat exchangers instead of getting drained and remains as a water column inside the Heat Exchangers. When we open the valve for next cycle, Steam enters (travels @ 25m/s) and makes the water column travel at same speed as steam, which becomes a potent and nuisance force capable of damaging floats – internals of Ball Float Steam Traps, tubes of heat exchangers and what not.

How to Handle Vacuum & Stalling.

  1. We must design our dryer in such a way that vacuum condition does not occur. It can be achieved by simply compartmentalizing your dryers in 2 Parts (2 Inlet & 2 Outlet of 50% capacity) and in last stage of drying by closing 1 inlet and 1 outlet (operating dryer at 50% capacity) valve, we can stop the vacuum creation.
  2. Ideal Air flow required is 1000 CFM/TONNE of paddy – During last stage supply of steam reduce drastically but the air flow remains same which gives rise to rapid and sudden decreases in the volume inside heat exchanger resulting in vacuum. Installation of VFD and reducing the frequency from 50 to 42 will also break the vacuum.
  3. Installing “Vacuum Breaker” and Thermostatic Air Vent – this will help greatly in controlling vacuum formation and improve the efficiency.
  4. Basic principal – Flow occurs from high pressure to low pressure only – without differential pressure(outlet pressure to be lower then inlet pr.) no flow will take place. “PPPU” pump is installed to take the condensate back to Boiler – PPPU pump exerts a back pressure of 0.5 bar on the whole system thereby reducing differential pressure to Zero or Vacuum – Sump Tank and pump will ensure zero outlet pressure.