The density of activated carbon
Activated carbon density is one of the important physical indicators, which is affected by many factors and has important significance in practical applications. When selecting and using activated carbon products, users should consider various factors comprehensively according to their needs and actual conditions and choose suitable activated carbon products.
Activated carbon density refers to the mass of activated carbon per unit volume. Activated carbon, also known as activated charcoal, is a porous form of carbon with a large surface area. Its density can vary depending on factors such as the type of raw material used, the activation process, and the specific application.
The density of activated carbon is typically expressed in units such as grams per cubic centimeter (g/cm³) or kilograms per cubic meter (kg/m³). The density can influence the performance of activated carbon in various applications, including adsorption processes in water treatment, air purification, and other industrial processes.
The activated carbon density or what some would say the activated charcoal density is all about filling a filter or filling a container. This means that the density of a product is important to understand, and this is not different with activated carbon compared to any other material.
The density of activated carbon in an important characteristic of both powder (PAC), extruded (EAC) and granular activated carbon (GAC). For powder activated carbon it is important to know the density for example for volumetric dosing in water purification and for extruded and granular activated carbon it is important to know the density when filling a filter with carbon for example for containerxane removal from biogas ( gas purification ). To understand the “density of carbon” a bit better we will briefly discuss the following density’s;
Apparent density of activated carbon (bulk density)
Apparent density backwashed and drained of activated carbon
Reactor density of activated carbon
Apparent density or activated carbon bulk density
The apparent density, sometimes called the bulk density of activated carbon, or volumetric density is defined as the mass of many particles of the activated carbon divided by the total volume they occupy. The total volume includes particle volume, inter-particle void volume, and internal pore volume.
If not tested in the same way then this density can vary greatly, so it is important that when the density is compared to other activated carbons this is done according to a standard like ASTM D 2854 -09(2019). With powders often it is also mentioned if it is "freely settled" (or "poured" density) and "tapped" density(where the tapped density refers to the bulk density of the powder after a specified compaction process, usually involving vibration of the container.
Apparent density backwashed and drained of activated carbon
The backwashed and drained density of activated carbon (GAC or EAC) is the parameter which is often used for sizing of adsorption equipment and to determine the weight of carbon required for liquid phase application like potable water purification. The backwashed and drained density will be lower than the apparent density because the space between the activated carbon particles will increase during the backwashing process.
As a reference point we can say that typically the apparent density of activated carbon will be in the range of 300 to 500 kg/m3, however this can also be outside of this spectrum because of for example raw materials used or activation level of the product.
Reactor density of activated carbon
This is the density of the activated carbon in the reactor (adsorber, filter or container). This density is often slightly lower than the apparent density because there are no specific conditions that let the carbon bed settle and this results in slightly more space between the particles compared to the way the apparent density is measured.
We expect that this additional understanding of density can support you in your product selection, compare carbon with carbon in terms of density, and to know the right amount of weight that you need for filling your container or filter.
Here let’s take a look at the packing densities of several commonly used activated carbons:
Coconut shell activated carbon is in the form of black amorphous granules and has the advantages of developed pores, good adsorption performance, high strength, easy regeneration, economy and durability. The standard bulk density of coconut shell activated carbon is between 0.5-0.55g/cm3. When purchasing a cubic meter of coconut shell activated carbon, its weight should be between 500-550kg.
Nutshell activated carbon is also black amorphous granular. It has the advantages of good wear resistance, developed voids, high adsorption performance, high strength, easy regeneration, economy and durability. The standard bulk density of nutshell activated carbon is 0.45-0.65g/cm3. If you buy a cubic nutshell activated carbon, its weight should be 450-650kg.
Powder activated carbon is black powder , which has the characteristics of good adsorption performance, high mechanical strength, easy to be regenerated repeatedly, and low cost. The standard bulk density of powder activated carbon is 0.38-0.45g/cm3, and the weight of one cubic meter of powder activated carbon should be 380-450kg.
Coal-based activated carbon is black cylindrical activated carbon, amorphous coal-based granular activated carbon, coal-based granular activated carbon has the advantages of high strength, developed pores, large specific surface area, especially large micropore volume. Coal-based activated carbon has a higher specific gravity, generally 0.6-0.7g/cm3, and one cubic meter is 600-700kg.
Honeycomb activated carbon has the characteristics of large specific surface area, small through-hole resistance, many and developed micropores, high adsorption capacity, and long service life. The shape specifications of honeycomb activated carbon are uncertain, so there is no specific value. Generally, the density of honeycomb activated carbon is between 0.45-0.65g/cm3, and one cubic meter is 450-650kg.
