Cleaning carbonaceous materials

Conrad Industries, Inc. (CentraUa, Washington) and Clean Air Products Company (Pordand, Oregon) have jointiy built a tire pyrolysis demonstration machine which allows recovery of combustible gases, oils, and other by-products. The equipment can also handle other carbonaceous material. It is designed to process 0.9 t/h of tires the entire system is estimated to cost about 2.3 x 10 . The feedstock consists of 5-cm tires chips which produce pyrolytic filler, a vapor gas yielding 11.5 kj/m (1000 Btu/ft ), and medium and light oils yielding about 42 MJ/kg (18,000 Btu/lb) (32). 

Steinberg, M., The conversion of carbonaceous materials to clean carbon and co-product gaseous fuel. 5th European Conference on Biomass for Energy and Industry, Lisbon, 1989. 

When electrochemical processes are used to clean up carbonaceous material, the only gas produced is COj here are no noxious products of partial combustion, such as NO and CO, to be injected into the atmosphere. When hydrogen is used in a fuel cell to produce electric power, it is made by splitting water and it produces water right back again as a by-product of the power generation. 

A carbonaeeous material (CA-3) weis supplied by the company RWE-Rheinbraun. It is a coke from German Rhenish lignite and it is well known all over Europe for its interesting applications in the field of waste gas and waste water cleaning. However, no information was given about its carbonization process. The textural parameters of this carbonaceous material are compiled in Table 1. 

The DWSA installation can be divided into two main parts. The first part consists of an air preheater, fluidised bed reactor, solid fuel dosing vessel with on-line mass determination system and a hot gas cleaning section, containing a cyclone and a ceramic candle filter (Schumacher type). In the fluidised bed reactor the solid fuel is gasified with air to produce a low calorific value (LCV) gas that is cleaned of fly ash and unreacted solid carbonaceous material. Air and also additional nitrogen can be preheated and is introduced into the reactor by four nozzles just above the distributor plate. The reactor is electrically heated in order to maintain a constant temperature over bed as well as freeboard section. The solid fuel is fed into the bed section in the bottom part Just above the distributor by a screw feeder from beside. The hot gas cleaning section ensures a good gas-solid separation efficiency, with filter temperatures of about 500 C. 

As a precaution against the gradual accumulation of small amounts of polymer in the reactors, they were cleaned before each run by maintaining a discharge in 02 at about 10 torr for 3 minutes to oxidize any carbonaceous material present. This was repeated twice, with fresh samples of 02. A discharge in H2 (about 10 torr) was then maintained for 3 minutes in the reactor. This was also repeated twice, with fresh samples of H2. Since the reactions studied were to be carried out in a reducing environment, this treatment with H2 was felt to be desirable after the 02 discharge. 

Coal refuse banks are cleaned prior to use in order to remove the carbonaceous material. In addition, modern coal refuse disposal practices mitigate this problem by placing the refuse in thin, well-compacted layers and covering all exposed surfaces with several feet of earth fill in order to reduce or eliminate the presence of oxygen needed to initiate or support combustion... 

Various coals cleaned in the Otisca T-Process contained in most cases below 1% ash, with the carbonaceous material recovery claimed to be almost 100%. Such a low ash content in the product indicates that very fine grinding liberates even micromineral matter (the third level of heterogeneity) it also shows Freon-113 to be an exceptionally selective agglomerant. 

Glass slides were immersed in chromic-sulfuric acid solution at 80°C for 40 min, which supplied active oxygen atoms that oxidize carbonaceous materials on glass surfaces, rinsed extensively with purified water, and then dried overnight in a clean oven at 120°C in air. All other glassware used was also carefully cleaned by the same process. 

It was the general need to clean carbonaceous residues from heat treated metals by spraying/soaking them in hot oil which led to cleaning machines in which the pressure was elevated above ambient. Other soil materials about which there was the same need were asphaltine tars, coke residue, aged grease, oxidized heat treat oils, waxy carriers, etc. 

The majority of easily detected compounds at solid anodes under constant applied potentials are self-stabUized via tt-resonance. Therefore, a desirable characteristic of electrodes in dc amperometry is inert. The electrode serves as a sink to provide and remove electrons with no direct involvement in the reaction mechanism. Since TT-resonance does not exist in polar ahphatic compounds (e.g., carbohydrates), stabilization of reaction intermediates is actively achieved via adsorption at clean noble metal electrodes. Faradaic processes that benefit from electrode surface interactions are described as electrocatalytic. Unfortunately, an undesirable consequence of this apiproach is the accumulation of adsorbed carbonaceous materials, which eventually foul the electrode surface. 

Any heat treatment of stainless steel should be preceded and followed by cleaning. Steel should be cleaned before heat treating to remove any foreign material that may be incorporated into the surface during the high-temperature exposure. Carbonaceous materials on the surface could result in an increase in the carbon content, causing carbide precipitation. Salts could cause excessive intergranular oxidation. Therefore, the stainless steel must be clean before it is heat treated. 

Wax-naphthalene or w y -phenol condensation products and their polymers are said to be effective as pour-point reducers. Viscosity Index may be improved by the addition of butene polymers or polymers of methacrylic acid esters. Detergency additives are usually complex calcium or barium sulfonates or phenates. Such additives tend to keep carbonaceous sludgelike materials from settling out of the oil and will even clean such materials from a dirty engine. When a detergency additive is used, the crankcase oil almost immediately appears dark and dirty because the sludge is carried in suspension. When such an oil is... 

Steinberg, M., Clean Carbon and Hydrogen Fuels from Coal and Other Carbonaceous Raw Materials, BNL-39630 Brookhaven National Laboratory, Upton, New York, 1987. 

Finally, Figure 20.7 shows the constitution of the rotary kiln with its screw device after 1800 h operation with different materials. The screw blades and the screw shaft are free from carbonaceous residues due to permanent cleaning by metal spheres and shredded goods. 

Most of these discussions regarding fluorine contamination of aluminum surfaces have focused on the conversion of aluminum oxide to fluoride or oxyfluoride. Evidence for similar conversions was included, and in extreme cases conversion to aluminum bonding quite similar to that in AIF3 was found. However, the poor adhesion of the samples skipping the O2 plasma treatment is related not to the fluorine contamination as such, but rather to the carbonaceous nature of the adsorbed materials, which is subjected to the plasma polymerization of TMS. Oxygen plasma cleaning removes this carbonaceous component, while the surface fluorine concentration is enhanced. 

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