Heat recovery from wet wood waste
Overall heat recovery from wet wood waste, particularly sawmill generated hog fuel, is improved by a process for predrying the fuel. A wet oversize fraction of the fuel is combusted in a fluid bed reactor providing heat for drying the remaining smaller sized fraction of the waste pile to about 10-30% moisture by weight. The gaseous products of the fluid bed burning are contacted with the fuel fraction in, preferably, a rotary dryer. The dried fuel is then screened into coarse and fine fractions. The coarse fraction is fed onto a grate of a wood waste boiler. The fines fraction is injected into the boiler combustion in an air suspension. The amount of fuel fed to the fluid bed reactor is 10-25% of the total fuel flow, depending upon the moistu content of the fuel. The gases fed to the rotary dryer are less than about 1,200/sup 0/F., to minimize ''blue haze,'' by combining with minimum outside air.
- Assignee:
- Weyerhaeuser Co
- Patent Number(s):
- US 4235174
- OSTI ID:
- 6794140
- Resource Relation:
- Patent File Date: Filed date 24 Nov 1978
- Country of Publication:
- United States
- Language:
- English
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