Generally in Food and Beverage processing and some other industries, water vapor is generated (at just above the atmospheric pressure) and vented to the atmosphere as waste. This ultra-low pressure water vapor can be utilized as a heat source to drive the vapor absorption chiller for catering to the chilling requirement.
Since these processes are mostly exposed to atmosphere, the mixture of water vapor and air (non-condensable gases) are coming inside generator tubes (heating portion of machine) and condense. This non-condensable gas plays crucial role in the system for achieving the capacity. We have a well-developed system for removing the non-condensable gases from the chiller. Condensed water is transferred back to the process for re-circulation.
Cycle diagram
Applications
Food Processing Industries
(Potato / Noodles / Savories Fryer)
Potato contains around 75% moisture so when they are fried the moisture is released in the form of vapor. The frying process being atmospheric, the water vapor leaves the fryer as a mixture with air and also has trace quantities of the entrained frying oil. These vapors are then simply taken to the chimney and vented out to the atmosphere. This leads to loss of not only valuable energy but also water.
These water vapors are now taken to vapor absorption chiller by blower and used as a heat source to cater chilling requirement.
Textile Industries
Continuous polymerization (CP) is a process which is used to produce polyester. The raw material used here is Terephthalic acid & Mono Ethylene Glycol which is continuously fed to the reactor and the polymer is continuously removed. During this process, high temperature water vapors are generated during the heating process of polymers along with some organic solvent. Normally, the vapors which are coming out of Process Column are condensed by an Air/Water cooled condenser. Here, we can provide ultra low pressure vapor absorption chiller to recover these water vapors instead of air or water cooled condenser. Hence, we can produce chilling for air conditioning and also reduce power requirements for condenser and electrical chiller.
Refineries & Petrochemicals Industries
In Refineries and Petrochemicals Industries, CO2 is let out along with high temperature water vapor. Ultra low pressure vapor absorption chiller can fit exactly for this kind of application also to recover the waste heat (water vapor along with CO2 gas).
Advantages
- Reduction in power saving for replacing electrical chillers
•Reduction in CO2 emission for replacing electrical chillers
- Utilization of water vapor to cater chilling requirement
- Condensate recovery water can be re-circulated for process
Case Study
A typical case for supplying absorption chiller for air-conditioning application utilizing the waste heat in the form of potato fryer vapours is as how below:
AUTHORS CREDIT & PHOTOGRAPH
P Babu
Mechanical Engineer
Thermax Limited
