Continuous pyrolysis plants

In addition to the batch process, Curti have finalised the design for a continuous pyrolysis plant to produce secondary raw materials and energy from waste tyres, which will be constructed according to a patented system. The capacity of the plant will enable it to process 10,000 tonnes of whole waste tyres per annum and will produce a number of products, for example ... 

Up to now, ATR077 has been produced only in a batch process, starting with char shipped from remote pyrolysis sites. American Tire Reclamation is currently planning to build a continuous classifier plant at a downtown Detroit location. This... 

Laboratory experiments were first conducted using a continuous pyrolysis reactor to establish optimal conditions for lube base oil production from polyethylene (PE). A pilot plant study was then carried out in a 1-gallon-per-day unit. The main findings included ... 

For large-scale continuously operating pyrolysis plants, a flnidized-bed reactor has numer-ons advantages such as improved heat transfer to the plastic, continuous dosing of catalyst and continnous coke removal. Fluidized-bed processes are however not efficient when applied on a relatively small scale. 

Except during startup, wood pyrolysis is reported to have been carried out commercially in the 1920s and 1930s without an external heat source. For example, the Ford Motor Company s continuous wood pyrolysis plant was... 

In order to simulate the condensing system of an industrial vacuum pyrolysis plant which consists of two condensing packed towers continuously operating, the liquids collected in each trap were mixed and then evaporated at 45 "C during half an hour in a rota-vapour (Biichi, RE 111). The heavy fraction which remained in the flask corresponds to the oil from the first condensing tower and is called bio-oil , while the evaporated fraction which consists of water and light organic compounds corresponds to the aqueous phase of the second tower and is called "aqueous phase . 

To examine the pyrolysis reaction of the scrap tires, pulverized scrap tires were heated in a quartz tube by an electric furnace (h). Then the continuous pyrolysis test plants in Table I were constructed to get the engineering data required for the design of an actual plant,... 

Industrial Engineering Chemistry Research 37, No.6, June 1998, p.2316-22 DEVELOPMENT OF A CONTINUOUS ROTATING CONE REACTOR PILOT PLANT FOR THE PYROLYSIS OF POLYETHENE AND POLYPROPENE... 

A pilot plant for the high temperature pyrolysis of polymers to recycle plastic waste to valuable products based on rotating cone reactor (RCR) technology. The RCR used in this pilot plant, the continuous RCR was an improved version of the bench-scale RCR previously used for the pyrolysis of biomass, PE and PP. 9 refs. 

Studies of 0/ 0 isotope variations in several vascular plant species, mosses and environmental surface bog water from temperate peat bogs (Switzerland) used as climatic archives for paleoclimatic reconstruction were reported by Menot-Combes et 8 0-values in organic material were determined by the online continuous flow method after sample pyrolysis at 1080 °C in the presence of glassy carbon in a Carlo-Erba elemental analyzer. The gases obtained (CO, N2 and H2O) were separated by passing them through a water trap and a GC column in a helium carrier gas. The isotope composition of CO was measured with a VG Prism II isotope ratio mass spectrometer relative to the VSMOW isotope standard. The overall analytical uncertainty is 0.08%o for water 8 0-values." ... 

The pyrolysis of mixed waste thermoplastics in a pilot plant of 360 ton/year at the Korea Institute of Energy Research (KIER), as shown in Figure 5.6, has an oil yield of about 82% for continuous process control over two days. The distribution of oil product is 27% gasoline product and 73% heavy oil product. Also the yield, of gas product is 10-15% and consists of about 18.1% Ci, 15.2% C2, 30.3% C3, 21.9% C4 and 14.3% C5 components. Similar results were obtained by other researchers, as shown in Table 5.1. 

An oil of low flash point in the range 14-18°C, and of 41-43 MJ Kg gross calorific value has been obtained in batch pyrolysis [36] of automobile tyre waste. In a pilot plant with semi-continuous feeding [37] the liquid yield of tyre waste decreased seriously with increasing temperature, and it was always lower in an atmosphere containing oxygen that in nitrogen. 

A 20 t/day plant (6000 t/yr) is equipped with two pyrolysis vessels (with dimensions of 2800 mm ID and 2000 m height). The vessels are fed with molten plastics by four extruders each with a capacity of 250 kg/h. The plant runs continuously and can feed waste plastics and discharge the solid residue while the plant is running. The liquid fuels are fractionated in a fractionation tower. The plant produces a liquid fuel yield of up to 80% (by weight), depending on the nature of the feedstock. 

The plant is controlled by a process computer (ABB-Hartmann and Braun) and equipped with numerous data-collecting instruments. Surveillance is carried out by continuous analysis of the room air as well as by explosion-limit controls. The pyrolysis gas is analyzed automatically by a gas chromatograph. All data obtained are registered to enable calculation of energy and mass balances. Some basic components are continuously monitored by infrared spectroscopy, i.e. ethylene in the pyrolysis gas, sulphur dioxide and oxygen in the exhaust gas. 

All modem olefins plants now under design and construction use indirectly fired tubular pyrolysis reactors. Although this type of reactor is presently undergoing several challenges (1,2), it should continue to hold a dominant position for many years to come. A tubular reactor may be simulated by a set of ordinary differential equations (3). Reaction... 

The PDU vacuum pyrolysis reactor is a semi-continuous horizontal pilot plant reactor 3 m long with a diameter of 0.6 m and a throughput capacity of about 50 - 200 kg/h, depending on the feedstock treated. The configuration of the PDU reactor is almost the same as that of the industrial reactor, except t t the PDU has smaller agitation blades. Two types of tests have been conducted with this reactor, the cold and the hot runs. In the cold tests, the particle flow behaviour is studied by a stimulus-response technique, under different agitation speeds and feed rates. The hot tests enable the conversion to be determined as a function of the feed rate and the agitation speed. 

The authors had already conducted the laboratory scale study and the preliminary pilot plant study, and proposed that "drying-pyrolysis process" (pyrolysis followed by indirect steam drying of dewatered sludge cake) (Fig,-i) could be one of the most economical and feasible alternatives for conventional incineration process. The authors have further conducted the feasibility study on a continuous system of "drying-pyrolysis process to evaluate the performance of the process in pilot scale, and to demonstrate its effectiveness as a thermal processing of sewage sludge. This paper presents the results of this pilot plant study. 

A Preliminary Economic Feasibility of the System. An economic feasibility for a proto-plant of 300 T/D in capacity can be estimated as follows By pretreating municipal refuse of 300 T/D, the input of the pyrolysis system is estimated to be about 83 T/D, assuming the total system is similar to that of the demonstration plant (100 T/D). The working period of the system is assumed to be 3 months continuously on three shift operation by 21 men, shift detail of which will be as follows ... 

Besides catalytic cracking, the only other major source of propylene in the near future will continue to be as a pyrolysis by-product. Even an all-chemical coal refiner will make little propylene. OCR estimates (13) that a 100,000 bbl plant will only produce 28MM lbs/years of propylene. The areas of significance that must be considered for now are the pyrolysis by-product processes. 

Table III shows the effect of shifting furnace operation from propane fresh feed to ethane. Data are from Schutt and Zdonik (54). The reduction of propylene yield from ethane to negligible levels in favor of increased ethylene production cannot be done if a plant has propylene commitments. Because propylene requirements cannot be satisfied with ethane feed, Ericsson (14) has concluded that propane will continue to be the preferred feedstock to make ethylene. Actually, 85% of the U.S. ethylene plants are located in the Gulf Coast area so that they can obtain and operate on economical ethane and propane feeds. The need for propane pyrolysis has resulted in a renewal of experimental interest in this area, and in-depth studies have been made by Crynes and Albright (17) and by Buekens and Froment (7).

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