This invention is in the field of systems for delivery of fuels to be supplied to a burner and more specifically fuel systems for the delivery of fine coal or coke.
Coal, particularly in the United States, offers an abundant, relatively inexpensive, and practical answer to fuel needs. In the past, however, there have been numerous technical, economic and environmental constraints that have prevented the utilization of coal. Most coal mined in the United States is burned by the utility market since the utilities can afford the expensive material handling requirements along with the transportation and environmental protection costs. The industrial market having individual lower requirements for energy as compared to the utilities have been unable to utilize coal due to the cost of the material handling system along with the environmental restrictions and the non-existence of a good delivery system. Heretofore, there has not been an existing method of obtaining convenient, easily stored, processed fuel from coal as compared to either oil or gas.
Disclosed herein is a fine fuel delivery system which is unique in that the fuel delivered is fine coal or coke and is conveniently stored in a ready-to-use condition within delivery containers at the user's site. Once the delivery vehicles or tanks are emptied, the truck tractor hauls away the empty tank and replaces same with a new tank filled with the ready-to-use fuel. Thus, the user is spared the necessity for investing in large capital equipment for storage and possibly even processing of the fuel while at the same time allowing the utilization of considerably less expensive fuel. Such a delivery system is especially convenient to small users of energy such as cement plants, lightweight aggregate operations, asphalt plants, small industrial boilers and similar facilities. The savings resulting from the elimination of the normal coal receiving, storing, processing and recovery equipment is therefore absorbed by the energy supplier who then may amortize the cost thereof over many purchasers achieving the same economies obtained by the aforementioned utility market.
The long term cost of coal is relatively known as compared to alternative fuels. Through the use of coal, smaller users may enter into long term fuel contracts allowing for the projection of costs with some assurance for five to ten years. The use of the delivery system disclosed herein also allows the extraction and use of a large supply of otherwise "waste" materials existing as pond coal or filter cake from preparation plants at attractive prices or other sources of heat energy; such as, newly mined coal, coke, biomass, etc. further providing for the attractiveness of the system.
It is known in Germany to pulverize coal to coal dust and then distribute same to remote users. Typically after pulverizing, the dust is stored in silos which include temperature and gas probes, and, explosion relief flaps. The dust stored in the silos is then transported by truck or railroad car while under an inert gas blanket to the site of the user and subsequently stored in smaller silos and then pumped to the burner as needed. Such a delivery system does not, however, utilize the delivery or transport vehicles for on-site storage. Thus, the user must still invest in the normal coal receiving and storage facilities increasing the direct cost to the user to the point where it is economically unfeasible for relatively small users to avail themselves of such a system.