Ash Wood
wood drying kilns
A wood drying kilns system to eliminate the discharge of liquid kiln water includes a kiln which is heated to dry a batch of wood, a basin to collect the water driven from the wood, and an evaporator in which the collected water is converted into steam. The steam is provided to the kiln to balance the drying and alleviate the splitting, warping, etc. caused by over drying. The steam is ultimately vented harmlessly into the atmosphere to effectively eliminate any discharge of the kiln water as a liquid.
- A process for drying wood comprising supplying wood to a kiln, heating the kiln to remove water from the wood, removing water from the kiln as a liquid, converting the removed water into steam, supplying the steam to the kiln, and venting the steam from the kiln to the atmosphere so that there is no discharge of liquid water.
2. A process for drying wood in accordance with claim 1 in which heated air is supplied to the kiln for said heating of the kiln, and wherein said heated air is used to convert the water removed from the kiln to steam before the heated air is fed into the kiln.
3. A process in accordance with claim 1 wherein the kiln is heated by a burner which supplies heated air containing ash to the kiln, and wherein the water removed from the kiln includes ash which is then separated from the water.
4. A process for drying wood in accordance with claim 3 in which the water separated from the ash is converted into steam.
5. A process for wood drying kilns in accordance with claim 3 in which the steam is supplied to the heated air outside of the kiln which reduces the amount of ash supplied to the kiln.
6. A process for drying wood comprising supplying wood to a kiln, supplying heated air containing ash to the kiln to dry the wood, and supplying the heated air with steam prior to the heated air entering the kiln and thereby removing a portion of the ash from the heated air.
7. A process in accordance with claim 6 wherein water expelled from the wood is removed from the kiln as a liquid, wherein ash is removed from the kiln with the water, and wherein the ash is separated from the removed water.
8. A process in accordance with claim 7 wherein the steam is generated from the water separated from the ash.
9. A process in accordance with claim 8 in which the steam is fed into the kiln with the heated air and then vented into the atmosphere with no discharge of liquid water.
10. A process for wood drying kilns comprising supplying wood to a kiln, supplying heated air containing ash to the kiln to heat the kiln and remove water from the wood, removing liquid water containing ash from the kiln, separating the ash from the removed water, converting the removed water to steam, supplying the steam to the kiln, and discharging steam from the kiln.
11. A process in accordance with claim 10 in which said water is exposed to said heated air before the heated air is supplied to the kiln to convert the water to steam.
12. A process in accordance with claim 11 in which a portion of the ash in the heated air is removed from the heated air by the steam prior to entering the kiln.
2. In the production of lumber products (e.g., boards, posts, etc.) the wood is dried prior to being planed. Typically, the lumber is stacked on rail cars or other carriages and moved into a kiln for batch drying of the wood. The kiln is heated by a burner to dry the wood over a set period of time. The moisture driven out of the wood is drained from the kiln and discharged into the environment.
3. The effluent produced during the drying process or during cleaning of the kilns creates a potential environmental hazard when discharged into rivers, lakes or other natural surroundings. States have therefore begun to ban or consider banning the discharge of water from the operation of kilns into the environment. As a result, wood drying facilities are faced with the prospect of shutting down for lack of a solution to the problem of disposing of kiln water.
4. Wood drying kilns have also generally suffered from an inability to provide uniformly dried products ready for planing or other processing. In particular, the moisture content in the individual lumber products is not uniform. Consequently, the time needed to dry each individual piece of wood varies from piece to piece. Nevertheless, for production purposes, the entire stack of wood is heated for a single predetermined time. As a result, some of the wood becomes over dry and suffers from cracking, warping, etc.
5. The burners of a direct fired kiln or the like are generally fueled, at least in part, by the shavings or other offal produced by planing or other processing of the wood drying kilns. Using the wood shavings as fuel provides an efficient, cost-effective management of the resources involved in the operation and solves a solid waste disposal problem. However, significant levels of fly ash generated in the burners is blown into the kilns. The ash, in turn, settles on the wood and in the water being driven out of the wood. As can be appreciated, the ash degrades the quality of the lumber, which can require an increase in the planing operation or a reduction in the final value of the product.
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A wood drying kilns system to eliminate the discharge of liquid kiln water includes a kiln which is heated to dry a batch of wood, a basin to collect the water driven from the wood, and an evaporator in which the collected water is converted into steam.