An Evaluation of a Pilot-Scale Plate-and-Frame Filter Press for Dewatering Fine Coal Refuse and Silica-Sand
Open Access
- Author:
- Verma, Shubham
- Graduate Program:
- Petroleum and Mineral Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 05, 2009
- Committee Members:
- Mark Stephen Klima, Thesis Advisor/Co-Advisor
Mark Stephen Klima, Thesis Advisor/Co-Advisor - Keywords:
- plate and frame filter press
Fine coal dewatering - Abstract:
- Laboratory testing was conducted to evaluate the performance of a pilot-scale plate-and-frame filter press for dewatering coal refuse slurries and silica-sand slurries. The fully automated filter press was manufactured by TH Minerals, Spain and is equipped with a hydraulic system, which operates the plate and diaphragm pumps. The filter press is capable of achieving an operating pressure of up to 150 psi. The unit contains a single set of plates having a filtration area 0.45 m x 0.45 m. Each plate is covered by a poly-propylene cloth with a pore size 0.051 mm. The first slurry sample was obtained from an anthracite cleaning plant located in Pennsylvania. This sample was collected from the plant’s refuse thickener underflow stream, which was feeding a belt-filter press at approximately 24% solids by weight. The sample was a nominal -0.2 mm and had an ash value of 50%. It contained approximately 50% of -0.025 mm material with an ash value of 68%. The second sample was collected from the thickener underflow stream of a bituminous coal cleaning facility located in Pennsylvania. This sample, which was approximately 35% solids by weight, was nominal -0.8 mm and had an ash value of 42%. It contained approximately 25% of -0.025 mm material with an ash value of 64%. The third sample was collected from the thickener underflow stream of another bituminous coal cleaning facility located in Pennsylvania. This sample, which was approximately 22% solids by weight, was nominal -0.14 mm and had an ash value of 15.0%. It contained approximately 65.3% of -0.025 mm material with an ash value of 20.9%. The fourth sample was collected from the thickener underflow stream of a silica-sand processing plant located in Pennsylvania. This sample, which was approximately 10% solids by weight, was nominal -0.14 mm. It contained approximately 37% of -0.025 mm material. A statistical design was developed for each sample using Minitab 15. The tests were carried out to evaluate the effects of feed solids concentration, filter time, probe level, air-drying time, and air-blow pressure on filtrate flow, filtrate solids content, final cake moisture, and filter press unit capacity. Overall it was found that the filter time and drying time had the most significant effects on product moisture and the unit capacity. For Plant 1, product moistures ranged from 22% to 28% with filtrate solids content of approximately 0.2% solids by weight. The unit capacities ranged from 0.8 kg/hr/m2 to 3.6 kg/hr/m2 corresponding to filter cake moistures of 17.2% to 26% respectively. For Plant 2, product moistures ranged from 23.5% to 25.5% with filtrate solids content of approximately 1% solids by weight. The unit capacities ranged from 0.81 kg/hr/m2 to 1.1 kg/hr/m2 corresponding to filter cake moistures of 23.8% versus 25.6% respectively. For Plant 3, product moistures ranged from 16% to 21% with filtrate solids content of approximately 0.07% solids by weight. The unit capacities ranged from 2.2 kg/hr/m2 to 4.2 kg/hr/m2 corresponding to filter cake moistures of 16.9% versus 26.1% respectively. For Plant 4, product moistures ranged from 11.9% to 17.5% with filtrate solids content of approximately 0.09% solids by weight. The unit capacities ranged from 1.9 kg/hr/m2 to 3.4 kg/hr/m2 corresponding to filter cake moistures of 28.4% versus 11.9% respectively. The results indicate that the filter press is capable of producing handleable filter cakes without the use of additional flocculants.