Miura Boilers Steam Things Up
For example, Pacific Nutritional Foods in Tualitin, OR was ready to significantly increase its tofu manufacturing capacity. Pacific takes the process right from the bean through to shelf-ready, consumer-packaged tofu. Since steam is an essential part of soybean processing, to reach its goal Pacific wanted to triple its steam production capacity.
Pacific Nutritional had a 300-hp firetube boiler, but it needed help. The process engineers decided to add 600-hp of boiler capacity, but the boiler room only had enough space for an additional 150-hp firetube boiler.
According to Miura, the expansion project manager had extensive experience with ultra-compact boilers in Japan. They knew they could fit three, 200-hp ultra-compact high-pressure watertube boilers in the space allotted for one 150-hp firetube boiler. Pacific decided to purchase two Miura 200 EX boilers and had room to spare.
SAVING TIMEPacific’s 300-hp firetube boiler required daily blowdowns. The man-hours required to do these blowdowns added up to one third of a workday per week. According to Miura, if Pacific had added two more firetube boilers instead of the Miura boilers, it would have meant that approximately six or seven hours a week — the equivalent of a day of work for one maintenance engineer — would be spent doing blowdowns.
Kerry Nading, Pacific’s maintenance managers, analyzed how many man-hours are consumed by the firetube blowdowns.
“We blowdown the firetube boiler every 24 hours. You have to open a valve for the front part of the firetube and you have to open another dump valve that will take it to the hot separator. Then, once you drain that for ten or fifteen seconds, you close those valves and open another valve to do the back end of the firetube,” said Nading. “It’s not difficult, but it is time consuming and you have to do it every day. You can’t walk away from it. You are opening a valve, waiting twenty seconds, closing that valve, and then starting the process of opening another one up. You have to be there, otherwise the firetube will go dry. You have to go through this process several times draining them out again. It will add up to twenty minutes a day — that adds up to a couple of hours a week.”
Miura Boilers says that Nading has seen that blowdown time with the new 200 EX boilers has consumed far fewer man-hours.
“To do a blowdown, you have to turn off the water, open some valves and drain all the water. Physically, you’re not standing there. What I will do is go back there to make sure it has enough pressure to blow down,” Nading says. “I’ll open the valves, then walk away, and about twenty minutes later I’ll come back there and make sure it is empty and start it back up.”
Since he is not tied to the boiler, Nading is able to work on another project while the Miura is draining. According to the company, the major savings is due to the reduced frequency.
Nading explains, “On the Miuras, we have to do a blowdown every 100 hours (not every 24 hours). That is approximately 20 minutes every 100 hours. With the Miura, it adds up to about half an hour a week.”
SAVING MONEYGenerally, it is necessary to call a boiler service company out for the yearly state inspection of a firetube boiler. According to Miura, these service companies charge from $90 to $100 an hour. The company claims that the Miura boilers do not require these service companies when the state does its inspections.
According to James Biery, maintenance manager for TransOcean Products, Inc., Bellingham, WA, a manufacturer of imitation crab meat, scallops, lobster, and smoked salmon, “When we have our firetube boiler inspected by the state inspector, we have to call in a service company. They are usually here for three to four hours.”
Biery adds, “There is very little maintenance with Miura. It just runs. The Miura’s yearly inspection costs almost nothing. It’s just going through the pop-offs, which are fairly cheap — I think, running somewhere around $30. The inspector takes about five minutes to do the inspection.”
For more information on Miura Boilers, go to www.miuraboiler.com (website).
Publication date: 04/01/2002