Rotary plough for gasifiers

Abstract

A solids handling equipment rotary plough (200) includes an elongate metal body (201) with a leading face (210) and a trailing face (212). The body (201) is configured to be mounted to a rotary component for rotation about an axis of rotation at least in one direction which is an operative forward direction such that the leading face (210) leads the trailing face (212). At least the leading face (210) has at least two major operatively upwardly and outwardly extending surfaces (202.1, 204.1) which are not coplanar. A first major surface (202.1) is angled operatively rearwardly and upwardly relative to the forward direction of rotation at an angle of at least 1° to the vertical. A second major surface (204.1) is angled operatively forwardly and outwardly at an angle of at least 1° relative to a radius of a circle described in use by the rotary plough (200) when rotating in the operative forward direction.

Description

FIELD OF THE INVENTION[0001]THIS INVENTION relates to gasifiers. In particular, the invention relates to a solids handling equipment rotary plough, to a rotatable grate assembly for a gasifier for gasifying carbonaceous material producing ash and to a gasifier for gasifying carbonaceous material.BACKGROUND OF INVENTION[0002]For some gasifiers, such as the Sasol® FBDB™ gasifier, it is necessary intermittently or continuously to load and unload particulate material, such as particulate carbonaceous material (e.g. coal) and ash. Thus, for example, in the case of a pressurized gasifier (e.g. a fixed bed dry bottom gasifier), particulate carbonaceous feedstock, e.g. coal, is loaded into a pressurised gasification chamber of the gasifier to form a bed (in the case of a fixed bed gasifier), and gasified at elevated temperatures and pressures, and after gasification any remaining ungasified material is removed from the gasifier as ash via a rotatable grate assembly and an ash lock.[0003]The...

AI Technical Summary

Benefits of technology

[0059]The rotatable grate component typically has a vertical dimension and a radial direction and is rotatable about a vertical axis of an ash discharge outlet of the gasification chamber, with a lower periphery of the rotatable grate component being below an apex or upper end of the rotatable grate component.

Problems solved by technology

In the operation of the short straight plough, severe erosion on the ploughs and other components of the rotatable grate assembly has been observed.

This causes an accumulation and compression of ash particles between the two ploughs, which leads to outward forces on the gasifier walls.

Ash particles wedged between the ploughs and the gasifier wall cause erosion patterns on the gasifier walls and on the components of the grate assembly.

This action however induces high torque loads on the drive systems which may eventually lead to mechanical equipment failure.

Erosion leads to increased maintenance costs, equipment downtime and production loss.

These are major operational inefficiencies caused by the inability of the ploughs of the prior art to remove ash in both the forward and the reverse operational modes of a rotatable grate assembly.

WO 2006 / 061738 also does not disclose any operational problems associated with the Sasol® Banana Plough™ or methods to solve them.

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