How growth can create headaches for dairy

A case study of how a Spirax Sarco audit led to an optimized condensate collection and return for improved control and energy savings.

02/12/2014


Expansion can be a mixed bag. With the satisfaction of increased production and revenues often come the headaches of rate limiting process stages and capacity ceilings. Such was the case at a North Carolina dairy operation, where growth had served to highlight serious deficiencies in the facility's steam operations. The dairy operation called Spirax Sarco for an audit of its steam and condensate system.

Initial Observations

The dairy operated one 200-hp boiler, which could normally handle the load, yet was approaching capacity. The Spirax Sarco audit showed operational costs to be excessive, especially boiler treatment chemicals, fuel and water. The first task was to reduce makeup water by returning condensate before looking at upsizing the boiler.

Some heat exchangers (HEs) had traps that dumped straight to drain, not returning condensate back to the boiler. Other HEs had small float and thermostat (F&T) traps on the coil outlet, with a 10' head to discharge, making the HE operate inefficiently in a "stall" condition. The only condensate return pumps were small, vented cast iron electric pumps. With the large head, these pumps cavitated frequently, exhibiting short life-spans and causing maintenance burdens.

Pasteurizing Improvements

The pasteurizing room had three HEs for milk and buttermilk. To correct condensate blocking and pump cavitation, Spirax Sarco recommended 1-1/2" Model APT14 Pump-Trap Systems be installed on each HE, positioned to remove condensate by gravity and eliminate the flash steam venting necessary with the old single electric condensate pump. Operating at temperatures above 212°F, the APTs could cycle more heat back to the boiler in the hot condensate, saving considerable energy.

Clean-In-Place (CIP) Heating Improvements

For heating clean-in-place solutions for ice cream, milk, and raw milk processing vessels, the dairy used four shell and tube HEs served by 1" or 1-1/2" solenoid operated (on/off) steam valves. The ice cream CIP HE had a 3/4" thermo-dynamic trap; the others had 1-1/2" F&T traps.

With closure of the steam valves, condensate formed in the HE tubes, and the gaseous phase went to vacuum. There were no vacuum breakers installed in the system. With the opening of the steam valves, significant stresses were forced upon the traps and the electric condensate pumps. Spirax Sarco recommended installation of 1-1/2" Model APT

Pump-Trap Systems for the four units. Two would handle condensate from the paired milk CIP units. The APTs would function as F&T traps, eliminating steam blocking when the steam valves opened.

Draining by gravity, they would remove the hot condensate more efficiently than the small electric condensate pumps they would replace. They would also conserve energy by eliminating both stalling in the HEs and the wasteful flash steam venting required to protect the misapplied electric condensate pumps. The pump traps were configured as skid-mounted package based on the benefits of simple, three connection installation and single-point responsibility by Spirax Sarco.

Based on the success with the processing vessels, attention moved to the case washer, milk production HE, raw milk CIP and orange juice heat set applications experiencing similar stalling and inefficiency problems. These problems were solved by the same pump-trap modules.

The Results

Conservative estimates of losses in pasteurizing and CIP solution heating totaled about $22,000 per year. Adding maintenance and spare parts costs, payback was estimated to occur in about 2 years. Next-phase optimizations included a hot water HE system with pneumatic control valve, pump-trap and controller; a pneumatically actuated KEA Control Valve, SP2 Positioner and a PN663 Controller; and drip leg traps for the main steam header.

- Content provided by Spirax Sarco, originally published in Steam News Magazine.

- Edited by Jessica DuBois-Maahs, Associate Content Manager, CFE Media, Plant Engineering, Control Engineering



No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
The true cost of lubrication: Three keys to consider when evaluating oils; Plant Engineering Lubrication Guide; 11 ways to protect bearing assets; Is lubrication part of your KPIs?
Contract maintenance: 5 ways to keep things humming while keeping an eye on costs; Pneumatic systems; Energy monitoring; The sixth 'S' is safety
Transport your data: Supply chain information critical to operational excellence; High-voltage faults; Portable cooling; Safety automation isn't automatic
Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Plant Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.

Maintaining low data center PUE; Using eco mode in UPS systems; Commissioning electrical and power systems; Exploring dc power distribution alternatives
Synchronizing industrial Ethernet networks; Selecting protocol conversion gateways; Integrating HMIs with PLCs and PACs
Why manufacturers need to see energy in a different light: Current approaches to energy management yield quick savings, but leave plant managers searching for ways of improving on those early gains.

Annual Salary Survey

Participate in the 2013 Salary Survey

In a year when manufacturing continued to lead the economic rebound, it makes sense that plant manager bonuses rebounded. Plant Engineering’s annual Salary Survey shows both wages and bonuses rose in 2012 after a retreat the year before.

Average salary across all job titles for plant floor management rose 3.5% to $95,446, and bonus compensation jumped to $15,162, a 4.2% increase from the 2010 level and double the 2011 total, which showed a sharp drop in bonus.

2012 Salary Survey Analysis

2012 Salary Survey Results

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.