Leggett & Platt (Jiaxing) Co. Ltd. – Jiaxing, Zhejiang, China
Branch 0529, Jiaxing, China, is part of Leggett & Platt’s Furniture Hardware Unit and manufactures components for recliners, sleepers, and coils. The facility uses 12 diesel burners to heat the ovens in the facility’s two paint lines. To reduce the high costs of diesel fuel and reduce air emissions, the facility investigated the use of hot blast stoves, which use low-cost pellets for fuel. The Jiaxing facility decided to first look at replacing the four diesel burners in the smaller line-tubing unit. Average fuel costs for the four diesel burners were approximately $13,740/month. The hot blast stove vendor guaranteed an energy cost reduction of 30%.
The fuel pellets are made from straw, sawdust, shell, and weeds. In addition to saving energy, the stove utilizes high-temperature burning technology that reduces emissions to allowable levels. By reducing air emissions, the need for air scrubbers is eliminated, thereby eliminating scrubber wastewater – an added environmental bonus.
Hot blast stove benefits:
- The stove project fell under the government’s Energy Performance Contracting program (details below). The supplier provides the equipment and the customer receives the benefit.
- The biomass energy value of the pellet fuel is very high. The pellets are made from agricultural wastes, such as straw, rice hull, sawdust, branches, etc., through a special process that improves the combustion performance of the agriculture waste.
- The service life of a hot blast stove is usually very short and the furnace tanks in commercial plants are generally guaranteed for only three months to one year. The new-technology furnace tanks are made of thermal-resisted materials and are guaranteed for three years.
- The biomass hot blast stove transmits heat to the required equipment through burning in the furnace tank and thermal conduction out. The exhaust is very clean and there is no concern about the particulate emissions.
In the Energy Performance Contracting program, the vendor is responsible for installing all new equipment and maintaining all equipment in good running condition. The vendor is also responsible for providing sufficient biomass fuel free of charge. Customer and vendor make an agreement on an hourly diesel consumption and cost by measuring the consumption of diesel for a certain period. The customer then pays the vendor what would have been 70% of the diesel fuel expense, resulting in a 30% reduction in fuel expenses. For the Jiaxing facility, hourly fuel consumption was determined to be $35.15/hour for one furnace and $45.34/hour for another. The calculated 30% savings were $10.54/hour and $13.60/hour.
Estimation of annual saving:
- Paint line tubing unit:
- Paint line mechanism unit:
- Annual total savings:
The tubing unit hot blast furnace was successfully installed this past fall. The mechanism unit diesel burners are now being replaced with hot blast furnaces.