Economic analysis of tire pyrolysis has several different aspects. First, the pyrolysis plant produces several outputs with commercial value. As in any other business establishment, these products are sold for profit. Secondly, it recycles auto tires, one of the most abundant waste products in the world. Globally 2.3 billion tires are produced in [1], and scrap tires constitute two percent of the whole solid waste [59]. The third aspect is related to energy efficiency. Most pyrolysis plants are self-sufficient in energy use. Byproducts of the pyrolysis process are feedback to fire furnace, and frequently byproducts are also used to generate electricity to supply power to the plant [60].
Click here to get more.
The gas component of the pyrolysis is primarily composed of hydrocarbons, which account for 80% of the content by volume. The remaining 20% includes CO, CO 2 , and SH 2 [ 47 ]. The energy content of the pyrolytic gas is 38&#;41 MJ/kg, which is close to that of natural gas [ 64 ].
There are several issues involved in using TDO as fuel. First, it has a lower flashpoint (temperature at which flammable gases are produced) than refined petroleum products, and the ignition of these gases will create a fire hazard. Unlike petroleum products, TDO is an unrefined product that includes more than 100 identified compounds [ 61 ]. Some of those compounds include volatile hydrocarbons that may ignite at lower temperatures. Although TDO has a viscosity comparable to that of diesel fuel, its high sulfur content makes it less appealing as an alternative fuel [ 50 ].
The yield of liquid products obtained from the pyrolysis of scrap tires is sensitive to operational parameters like reactor type, particle size, heating rate, pyrolysis temperature, and holding time. Among these, the pyrolysis temperature has a significant impact on the yield. Previous work in this area emphasizes that the liquid output is maximized at about 450&#;550 °C, with an approximate yield of 50 wt. % [ 30 , 50 , 64 ].
The liquid product of pyrolysis is commonly named tire-derived oil (TDO) and has a dark-brown color and sulfuric odor like petroleum extractions. TDO is a complex mixture of high carbons with aromatic and aliphatic compounds [ 47 ] . Depending on the tire type and materials used in manufacturing, the energy content of TDO can reach up to 44 M.J./kg, which is equal to the energy consumed to manufacture a tire [ 62 , 63 ].
As a commercial product, the char has limited potential compared to liquid and gas components. It cannot be reused as raw material because of impurities in its content. Sulfur, ash and dirt make it less appealing to be recycled back into tire manufacturing. However, char has the potential as a reinforcement agent. It can be used as reinforcement material in the rubber industry, particularly in the production of shoes, conveyor belts, and dock fenders [ 22 , 60 , 60 ]. Char material can be upgraded to higher quality carbon to be used as fuel [ 60 ]. The other apparent solid output is steel which is directly sold as scrap material.
The pyrolytic char content of an ELT ranges between 22% to 49% by weight, as reported in the review of previous studies [ 61 ] . Although the range seems wide, most studies report a percentage figure between the high 30s to low 40s. The char is mostly a high carbon that composes 90% of the char material, followed by sulfur with a ratio between 1.9% to 2.7% by weight. The remaining part is dirt, which reportedly ranges between 8.3% and 15.3% [ 61 ] and comes from additive materials used in manufacturing and dirt found in waste tires.
Each output category&#;solid, liquid, and gas&#;has a different economic value, and the commercial potential of each category is discussed separately. Since the gas product is the most difficult to transport, it is used in the plant to power the reactor and the remaining gas may be used to power a small turbine-generator combination to produce electricity for the plant.
Pyrolysis outputs can be categorized into three groups&#;solid, liquid, and gas&#;based on the form of the final product ( ). Depending on the reactor type, scrap tires are fed either as whole tires or pre-shredded pieces. The solid output that comes from the reactor is called char. Vapor output is fed into the condenser for distillation. The liquid output from the condenser is called tire-derived oil (TDO). The third component is a hydrocarbon-rich gas like natural gas, in terms of energy content.
In the economic analysis of the pyrolysis system, there are three components that require discussion: investment costs, revenue streams, and general costs. The first, the initial investment cost, is the lump-sum money committed at the beginning of the investment and is generally proportional to the size of the investment (i.e., output capacity). Although there is a positive relationship between capacity and investment cost, the relationship is not linear. As capacity increases, the marginal cost of investment declines. Building bigger plants is more economical because the investment cost per unit capacity declines with the size of the investment. Of course, this is not the only factor in deciding the capacity of a plant. Other significant factors include potential market demand or availability of capital for investment.
Building a pyrolysis plant is a long-term investment. In feasibility studies of such plants, an investment life of 15&#;20 years is typical [65, 66, 67]. With such a long investment horizon, the initial investment cost becomes less relevant, and a constant factor based on per unit production is sometimes used in feasibility studies to account for initial investment cost. Islam and co-workers calculate the unit production costs for three different scenarios with daily ELT processing capacities of 3.6, 36, and 144 tons per day, respectively [64]. These calculations are based on investment and fixed and variable costs, and then converted to unit production cost (i.e., US dollars per ton).
The second and third factors of the economic analysis are revenue and general costs. In terms of direct cost, personnel and energy are two major items. For all other costs, a fraction of personnel or personnel plus energy is added to the cost list.
When building a pyrolysis plant, there are four potential revenue streams: the carbon coming out of the reactor; the steel used in rubber tires, which is extracted at pre-processors; TDO, which is similar to heavy fuel oil; and a gas output that is rich in hydrocarbons and has an energy value equal to that of natural gas.
For the economic analysis, an additional factor that must be considered is the tipping fee, which is a cost associated with dumping tires into a landfill. Some EU countries have already banned the use of landfills; in others, the current fee is approximately &#;100 per ton. As rules regarding opening and maintaining landfills become more stringent throughout the world, this cost is expected to increase. From a broader perspective, the tipping fee can be considered a disposal fee for the user; however, in our modeling, the fee was considered to be a revenue item.
shows unit prices for the products that are extracted through the pyrolysis process and includes both prices reported in the literature and the current market prices for steel and TDO. The percentage of each component by weight is also included in the table.
shows the schema for a tire pyrolysis plant. It is common practice in the industry to use the gas output as fuel for the reactor. The gas can also be used to generate electricity through a gas turbine generator combination. Mini- and micro-power generation has spread recently, and prices have decreased to affordable levels. There are even gas turbine-generator combinations priced at $10,000 that are promoted for household use [70]. Considering that gas produced through pyrolysis and natural gas have almost identical characteristics [64], a turbine-generator combination that can burn both gases can be built to power auxiliary systems throughout a facility.
Goto Sihai Energy to know more.
As reported in the literature, the weight percentage of solid, liquid, and gas contents vary depending on the incoming scrap tire mixture. A similar variation is also observed in the energy content of output products. There is a spread in the reported caloric output of pyrolytic liquids and gases [62]. lists price and weight ratio of each pyrolysis component used in the analysis. Assumptions regarding price and weight ratio are based on the analysis reported in previous studies [62, 64, 65, 68]. An obvious advantage of adding an electricity generation capability to a system is to take advantage of variations in inputs and outputs. When scrap quality is high, there will be excess gas, which will be used in electricity generation. In case of a deficit, a plant can use urban natural gas to fire turbines or electricity from the grid.
For cost analysis, the initial capital cost is the first to consider. Islam and his co-workers cites several previously built plants and gives the cost and capacity for each [64]. A plant in Shanghai, with a capacity of 25 tons/day of scrap tire, had an initial investment cost of $2.5 million. A similar plant in Taiwan was built for $3.5 million. Another factory in Taiwan has a capacity of 30 tons/day and was constructed for $3 million. A larger plant in the US with a capacity of 100 tons/day had a cost of $4.863 million.
Islam and co-workers standardized various cost items and expressed them as unit production costs at various production capacities [64]. gives unit production costs for three different production capacities.
A mid-sized pyrolysis plant with a capacity of recycling 30&#;40 tons of scrap tires per day generates $222 per ton. Processing one ton of scrap tires costs around $200 per ton, with the assumption that gas generated through the pyrolysis process can power the reactor and the gas turbine. The difference between revenue and cost is $22 per ton, which may be regarded as an unappealing profit margin. Considering the price volatility of outputs, the plant may not be profitable, at least during the periods when the demand for pyrolysis products is depressed. Even with the small profit margin of $22 per ton, there is a potential profit of $6.6 million if all 0.3 million tons of ELT is sent to pyrolysis plants. This potential is expected to reach $4.4 million in , with increasing ELT output.
In the last decade, the economy and technology of China have been developing rapidly. The waste tyre pyrolysis technology is no exception. With the development of the international trade, more and more customers choose to purchase waste tyre pyrolysis plant from China. What advantages are there?
1. Mature waste tyre pyrolysis technology and rich installation experience
Firstly, the waste tyre pyrolysis technology researched by Chinese suppliers not only suits waste tyres, but also can be used to process waste plastic, waste rubber, oil sludge, coal tar, etc. Like our company -- Henan Doing Company, we have installed many pyrolysis plant projects in different countries and regions, like 72TPD waste tyre pyrolysis plant project in Australia, 4 sets 10TPD waste tyre pyrolysis plant project in South Africa, 12TPD waste tyre pyrolysis plant project in Serbia, 12TPD waste plastic pyrolysis plant project in Indonesia,etc. So we have accumulated rich installation experience of waste tyre pyrolysis plants.
DOING waste tyre pyrolysis plant projects in many countries
2. Mature engineers team and best after-sale service
Secondly, Chinese manufacturers generally have mature engineers team for designing the waste tyre pyrolysis plants. Like us, we not only have professional engineering team for designing proposal for clients according to the specific requirements, but also have our own factory to manufacture quality machines with favorable price. Besides, we have responsible after-sales team who can ensure machine installation, commissioning and successful running.
DOING factory
3. Building office and warehouse in different countries
About this point, Henan Doing Company is the leader in this regard. Other Chinese suppliers have not do it yet. At present, we have successfully set up our first branch in Lagos, Nigeria, which provides more convenient for our African customers. Besides, we are planning to open more and more office and warehouse in more countries, so that clients can get better after-sales services and spare parts easily.
Our warehouse in Nigeria
Do you also want to purchase waste tyre pyrolysis plant from China? Don't hesitate, leave your special requirements to us, then we will arrange sales manager to contact with you immediately and give you personalized services accordingly.
The company is the world’s best Waste Tyre Pyrolysis Plant Supplier supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.