ES2214970A1 - Modification of high hydrocarbon paste waste by e.g. dolomite comprises inertizing to yield granulate controlling acidity - Google Patents

Abstract

The modification of high-hydrocarbon paste waste by e.g. dolomite comprises inertization by 40-70% of dolomite relative to the wet weight of the mixture. The recommended minimum contact time is twelve hours, yielding granulate and facilitating recycling. The product controls the acidity of e.g. thermal power station dumps.

Description

Procedure for inertization and conditioning of pasty residues rich in hydrocarbons by mixed with conventional whitewashers.

The technical sector corresponds to treatment, inertization and promotion of waste recycling pasty consistency with the presence of significant amounts of hydrocarbons

Pasty residues rich in hydrocarbons, such as those derived from beach cleaning and coasts affected by spills of fuel, oil and products similar, present different problems. It may happen that such wastes are not suitable for use as fuels in thermal plants, because of the presence of significant amounts of solid impurities (for example, arenas) or limitations related to their starting characteristics (for example, too high sulfur contents, which can make unacceptable or inappropriate combustion for use energy in certain circumstances). In such case, it is It is necessary to have the logistics to ensure the evacuation of waste from sensitive areas from which they are removed (beaches and costs) and subsequent storage and treatment. When the quantities to be stored are very high, as usually happens in cases of massive spills linked to accidents of high ships transport capacity, pasty waste management not undergoing inertization and conditioning treatments Additional problems can become a serious problem, which aggravates the caused by the discharge itself into the sea.

Currently, this type of pasty waste They are usually stored temporarily in large rafts -principally of waste management companies- with capacity for thousands of tons and, if not finally burned in plants of energy use, we must try to find some appropriate means of conditioning and subsequent inertization, which it will be variable according to the particular characteristics of the residue, and for which there is no clear definition and protocol standardized standard applicable with probabilities of success.

The problem affects pasty waste, consisting of hydrocarbons, derived from ship discharges, that reach beaches and coasts, and are subsequently removed, with often emulsified with water and mixed with sands, algae...

These pasty residues cannot always be used to generate energy by combustion, because of the high content of solid impurities that accompany them, or due to other limitations or impediments of a physical or chemical nature. When this case occurs, temporary storage of waste can become an additional serious problem. In fact, if the origin of the waste corresponds to a massive spillage, derived for example from an accident that has affected a ship with high transport capacity, the availability of enclaves or facilities suitable for the deposit of problematic substances can be complicated and insufficient. On the other hand, in the absence of an exit through the use of energy, it will be necessary to consider some alternative treatment and conditioning, after having undertaken temporary storage, since it could not be considered appropriate to stop promoting its inertization and recycling if they are
feasible

In this invention we propose solutions making the mixture of pasty residues, rich in hydrocarbons, with conventional whitewashers, in particular with lime viva (consisting essentially of calcium oxide, regardless of higher or lower impurity content), calcined dolomite (consisting essentially of calcium and magnesium carbonate) and limestone (consisting mainly of calcium carbonate).

Making the mixtures in the proportions adequate, in a certain order, with a certain contact time and using fine particle sizes for the whitewashers manages to transform pasty hydrocarbon waste -Characterized by its adhesion, certain fluidity and sometimes for unpleasant odors, especially for the presence of sulfur compounds - in solid consistency materials, powdery or granulated, depending on the whitener used and the mixing ratio), which are easy to handle and store as solids, without the need for containment rafts, with remarkable resistance to water, with reduced odor and with physicochemical characteristics that reduce its potential toxicity and that allow to consider its use and recycled as a complement to agronomic management in dumps or combustion tanks of thermal power plants, or even on certain substrates or soils in non-sensitive areas, mainly with low risk transmission environments of pollution. The potential use as agronomic complement of resulting mixtures - mainly linked to the pH clearly alkaline, which generally exceeds the value of 12-, and the content in calcium, and also in magnesium if dolomite has been used, it allows focus them as correctors of the acidity characteristic of sterile of the thermal, and favors recovery strategies of the substrate.

The procedure to implement the mixtures between pasty residues rich in hydrocarbons and conventional whitewashers will depend on the degree of automation that You want to enter the process. Essentially you need a container container for mixing, a hopper suitable dimensions, preferably with turning capacity and flip to facilitate contact between components; and an area for temporary storage of mixtures. They can be used conveyor belts to move products to the hopper mixing, paying attention to adhesion characteristic of hydrocarbon waste. These means mechanics are common in the application of procedures conventional sludge stabilization from the wastewater treatment (Spanish patent P200200443). It is also appropriate to have a zone or silo of storage for the whitewashers, so that there are remnants Available for mixing. In the same way, it is convenient reserve a space for the reception and temporary storage of hydrocarbon waste, for example in a raft waterproofed by its base and sides, and preferably at shelter from rainfall.

Embodiment

Starting from the materials separately, the hydrocarbon waste and one or the other of the whitewashers conventional with relatively fine particle size (such as they are supplied commercially) the mixing of the two products (using hopper, turner and tapes conveyors if necessary and according to the degree of desired automation for the process, not forgetting the power waste adherent, which can be partially solved systematically disposing thin layers of whitener over the conveyor of pasty hydrocarbons), in proportions usually between 40% and 70% of whitener with regarding the wet weight of the mixture, and the rest of the pasty residues of hydrocarbons up to 100%, although these proportions are could modify - without limitation of departure - depending on the characteristics that are desired for the final product, such as the consistency or pH.

Frequently, the best result in terms of inertization corresponds to mixtures containing 60% of whitewasher and 40% of hydrocarbon residues (in wet weight of the mixture). Mixing will preferably be done by first adding a dose of the whitener to the hopper, followed by the corresponding dose of the residue, then proceeding to mechanical mixing, then adding a new dose of whitener and then the corresponding proportion of the residue, then proceeding to a new mechanical mixing of the set, and so on until reaching the volume of mixing programmed by the directors of the process in situ . The mixtures obtained may be stored temporarily in available places, preferably protected from the impact of precipitation.

When the whitewash used is quicklime, if leave a few hours after mixing with the waste of hydrocarbons (preferably 24 h), turning or removing from Again the mixture is favored that the final product acquires a powdery appearance, with reduced particle size and even whitish coloration on occasion and for percentages of lime in around 60% in the wet mixture. However, when it is used calcined dolomite or limestone as a whitener, the resulting mixture It has a more grainy appearance. The mix response with the different whitewashers on contact with water also presents individual differences, but in no case a behavior that can be considered more worrisome than present pasty hydrocarbon residues not treated by medium of the indicated mixing alternatives.

After a minimum contact time, about 12 hours, or preferably 24 hours if possible, mixtures acquire characteristics that will allow them to be used as agronomic management supplements, preferably for recovery of sterile or debris from thermal power plants, providing alkalinity, calcium and magnesium (the latter if dolomite is used) to different substrates that can be favored upon receiving the product.

Claims (3)

1. Procedure for the inertization and conditioning of pasty residues rich in hydrocarbons by mixing with conventional whitewashers, characterized by mixing two components: one component is conventional whitewashers, such as quicklime, calcined dolomite or limestone; and the other component pasty residues rich in hydrocarbons; establishing a contact time between 12 and 24 hours; and the percentages between the components vary depending on their starting characteristics and the characteristics of the mixture that is intended to be achieved, which will preferably be comprised: a) Between 40% and 70% of the whitener Conventional to be used, referred to wet weight of the mixture; b) Between 60% and 30% of pasty waste rich in hydrocarbons, referred to the wet weight of the mixture. 2. Mixture or mixtures according to claim 1, for the inertization and conditioning of waste from hydrocarbons that are part of these mixtures. 3. Mixture or mixtures according to the claims above, for use as an agronomic complement in the recovery of waste dumps or combustion tanks of thermal power plants or other substrates that can be seen their physical-chemical conditions improved.